Cell complexity (Introduction)

by David Turell @, Friday, November 09, 2012, 15:26 (4185 days ago)

The Central Dogma is the current basis for Darwinism. With cell systems research it is an inadequate explanation of how life really works. as I have predicted, the complexity is overwhelming, and not the straightline simplicity of the Central Dogma. Shapiro has told us this.-"Because of its simplicity, the central dogma has the tantalizing
allure of deduction: If one accepts the premises (that DNA
encodes mRNA, and mRNA, protein), it seems one cannot
deny the conclusions (that genes are the blueprint for life). As
a result, the central dogma has guided research into causes of
disease and phenotype, as well as constituted the basis for the
tools used in the laboratory to interrogate these causes for the
past half century.
The past decade, however, has witnessed a rapid accumulation
of evidence that challenges the linear logic of the
central dogma. Four previously unassailable beliefs about the
genome—that it is static throughout the life of the organism;
that it is invariant between cell type and individual2...4; that
changes occurring in somatic cells cannot be inherited (also
known as Lamarckian evolution5); and that necessary and
sufficient information for cellular function is contained in the
gene sequence—have all been called into question in the last
few years. Revelations of similar scale have occurred in the
transcriptome, with the discovery of the ubiquity (and variety)
of mRNA splicing.6 So too with the proteome, which has
undergone perhaps the most dramatic shift in understanding
as a result of the aforementioned changes to the transcriptome
and the genome, as well as by the explosion of technology
development that has enabled both quantitative and qualitative
analysis of large groups of proteins and their modifications
in a single experiment. It is now clear that information
flows multidirectionally between different tiers of biological
information, of which genes, transcripts, and proteins constitute
only the most obvious 3.
The ostensible fourth step in the central dogma—how
molecules "encode" cells— clearly lacks the crystalline formulas
that relate DNA to protein. Although molecular details
have been revealed for thousands of cellular events, no model
exists that can explain how, for example, the modest erythrocyte
is formed without error 2 million times per second in
adult Homo sapiens. In contrast to a blueprint that can
perfectly describe how to assemble a motorcycle or to build
a city, we lack the knowledge to explain how a cell forms
with correct processes operational, cellular structures formed,
and signaling mechanisms in place. It is in attempting to
extend the central dogma beyond proteins that one realizes
the logic of biological systems and engineered ones are
fundamentally different.7 Just as the central dogma did for the
investigation of basic and medical biological problems, a new
synthesis for how cells form and function will result in
philosophical shifts in research, as well as technological
breakthroughs to enable it."-http://circgenetics.ahajournals.org/content/suppl/2011/11/08/4.5.576.DC1/HCG200254.pdf-
These folks are still not thinking about Intelligent Design, hanging on to a belief in chance.

Cell complexity

by David Turell @, Friday, November 23, 2012, 15:15 (4171 days ago) @ David Turell

Fatty acids play a major role in membrane formation and gene expression and control. A map:-http://www.the-scientist.com/?articles.view/articleNo/33047/title/PUFAs-At-Work/

Cell complexity

by David Turell @, Tuesday, December 04, 2012, 15:22 (4160 days ago) @ David Turell

A video of cell complexity:--http://youtu.be/4GZXRMG5i_w

Cell complexity:cell entry

by David Turell @, Wednesday, February 27, 2013, 19:30 (4074 days ago) @ David Turell

How to get through a cell membrane requires a complex control molecule, the structure of which is now discovered:-http://phys.org/news/2013-02-d-crystal-important-human-proteins.html

Cell complexity:mitochondria release energy

by David Turell @, Sunday, June 30, 2013, 00:53 (3952 days ago) @ David Turell

Another very complex biochemical mechanism to control energy flow to the cell:-"The energy released from the rupture of chemical bonds in food molecules is stored temporarily in the form of high energy electrons in two types of molecule, N and F, whose proportions vary depending on the nutrient source. By themselves, these molecules cannot provide a freely utilizable source of rapidly mobilized energy for the cell's needs; access to this stored energy requires the mitochondria, which uses five molecular machines, called complexes I, II, III, IV and V, to convert the energy stored in N and F molecules into the universal energy source ATP.
 
"Until very recently these complexes were thought to float freely and independently in the internal membrane of mitochondria, without interacting. Work by Dr. Enriquez's group has now shown this view to be incorrect. "The five complexes do not always move independently in the membrane," explains Dr. Enríquez. "On the contrary, they associate in distinct combinations called respiratory supercomplexes. Our work explains the functional consequences of these interactions."
 
"The study shows that these associations are dynamic and are modified to optimize the extraction of energy from N and F molecules depending on their relative abundance, which in turn reflects the composition of foods consumed in the diet.
 
"The Science study describes these supercomplexes and their functions. The significance of this, in the words of Dr. Enriquez, is that "the system for optimizing the extraction of energy from food molecules is much more versatile than was believed and can be modulated in unexpected ways in order to adjust to the dietary composition of nutrients or to the specialized function of particular cell types.'"-
http://www.sciencedaily.com/releases/2013/06/130627142404.htm

Cell complexity: Golgi apparatus function

by David Turell @, Friday, December 20, 2013, 15:58 (3779 days ago) @ David Turell

Many newly synthesized proteins undergo a sequence of enzymatic modifications that enable them to do their jobs better. This process occurs within a series of membrane-bound structures called 'cisternae' that form the Golgi apparatus—an organelle that packages proteins before they are sent to their destination. Akihiko Nakano, Yasuyuki Suda and colleagues at the RIKEN Center for Advanced Photonics have now gained important insights into how protein movement through the Golgi apparatus is regulated.
 
When new proteins are produced, they are deposited into cisternae on the 'cis' side of the Golgi. These proteins undergo a maturation process as they migrate toward the 'trans' side of the Golgi before being released into the cell as fully processed proteins -
Read more at: http://phys.org/news/2013-12-protein-line.html#jCp

Cell complexity: Golgi apparatus function

by David Turell @, Friday, December 20, 2013, 18:58 (3779 days ago) @ David Turell

Another article on Golgi apparatus showing that the centrosome isn't always in charge under guidance from the nucleus.:-"In neurons, microtubules are essential for generating the axonal and dendritic extensions that carry electrical impulses. In most cells, these cylindrical polymers of tubulin grow from centrosomes, but in neurons, centrosomes lose function as the cells develop, suggesting another point of origin for this essential structural protein."-http://www.the-scientist.com/?articles.view/articleNo/34771/title/Branching-Out/

Cell complexity: Sensing stress

by David Turell @, Friday, December 20, 2013, 19:06 (3779 days ago) @ David Turell

"At the cellular level, physical stress is ever-present and inescapable. Whether externally applied, as when bodies move, bend, and stretch, or internally generated by the cytoskeleton as cells change position, mechanical forces trigger changes in intracellular biochemical signaling and gene expression, influencing processes such as migration, proliferation, differentiation, and apoptosis. For instance, stem cells have been shown to differentiate into different cell types depending on the stiffness of the matrix on which they are grown.
 
"Force is increasingly recognized to play a vital role in regulating cell behavior and function, and researchers are beginning to elucidate the mechanisms by which cells sense and generate mechanical forces and translate them into biochemical signals—a process known as mechanotransduction. In the past few years, a number of techniques have cropped up to examine how such forces regulate biochemical signals and thus, ultimately, cell function, but many of these tools are limited to the investigation of single molecules in vitro and are challenging to use in living cells. Here, The Scientist profiles three techniques that have been developed to measure forces inside of or applied by living cells."-http://www.the-scientist.com/?articles.view/articleNo/37216/title/Sensing-a-Little-Tension/-Note biochemical signalling under gene expression control. Seems automatic to me

Cell complexity: working molecules

by David Turell @, Monday, December 23, 2013, 15:39 (3776 days ago) @ David Turell

Just like factory workers, molecules shepherd products to the finish of the production line:-"They saw salt bridges form and the enzyme grab helices and pull them apart. The growing chain of fatty acids also loops back into a pocket in the carrier molecule. "We call it the marsupial protein," Burkart says. "It protects its young." That is, until it's time for the product to go.
 
"We thought this tiny protein was just a transporter," Tsai said. "But when it ejects its cargo, it works like a piston. We see a helical collapse forcing the fatty acid out.'"-
 Read more at: http://phys.org/news/2013-12-biosynthesis-captured-motion.html#jCp

Cell complexity: working molecules

by David Turell @, Thursday, May 15, 2014, 15:40 (3633 days ago) @ David Turell

How kinesins carry loads across microtubules:-https://www.youtube.com/watch?feature=player_detailpage&v=gbycQf1TbM0-From Discovery Institute, but legitimae science

Cell complexity: phospholipids

by David Turell @, Tuesday, October 07, 2014, 15:29 (3488 days ago) @ David Turell

Carry proteins across cell walls, but do more than that:-http://phys.org/news/2014-10-reveals-messenger-molecules-cell-walls.html-"Researchers focused on messengers called signaling phospholipids that act like bellhops in cell walls, escorting proteins to compartments within a cell and activating their functions. The results could explain why these messengers had been observed linked to proteins in the nucleus of cells; their purpose there had been a mystery.
 
"X-ray crystallography at SLAC's Stanford Synchrotron Radiation Lightsource, a DOE Office of Science User Facility, provided the first detailed look at how this messenger acts as a hormone in binding to a specialized hormone-sensing protein called a nuclear receptor."-In the cell each special molecule has an assigned job. Cells are factories, and they rely on the specialization of these molecules. But each molecule can have any number of 3-D shapes and parts. How did evolution find exactly the right ones to fit together? If evolution had to search for the 'right' form of each functional molecule out of millions of possibilities, how did evolution find the right ones in the time available. And evolution works by chance?

Cell complexity: study of one molecule

by David Turell @, Wednesday, December 10, 2014, 15:20 (3424 days ago) @ David Turell

This paper shows how complex is the activity of one giant protein molecule in the cell membrane, controlling probably three functions:-http://www.the-scientist.com//?articles.view/articleNo/41505/title/Cadherin-Connection/-"When clustered together in tissues, cells sense and respond to their neighbors by way of membrane receptors, which relay signals informing individual cells when and in what directions to multiply. The loss of—or failure to respond to—these cues can spill over to cause cancer or other diseases. Researchers previously knew that one such surface receptor, a conserved cell-adhesion molecule dubbed Fat (Ft) cadherin, functioned in two ways, regulating tissue organization and a tumor-suppressive signaling pathway known as Hippo. Now, a new study suggests this molecule may have a third role: linking cell proliferation to mitochondrial respiration."-This is the 'sentience of cells' that dhw loves to quote. What fascinates me is how the research folks tease the process apart.

Cell complexity: study of another molecule

by David Turell @, Wednesday, December 10, 2014, 18:42 (3424 days ago) @ David Turell

This is a study of the handling of an unfolded protein by the cell. Loss of folding means loss of function:-http://www.sciencedaily.com/releases/2014/12/141210082006.htm-"The unfolded protein's slowdown is not only due to size, however. The researchers did additional experiments to prove that the unfolded protein stuck to other molecules in the cell. A class of molecules in the cell called chaperones have the job of binding to parts of proteins that come unfolded, and the researchers found that the unfolded protein interacted more with chaperones than did the properly folded protein. However, when high numbers of proteins unfold, the cell's systems can get overloaded and the chaperones can't handle them all.-"Looking at something like this can start to give people a handle on why something that seems relatively harmless in vitro sometimes can have such a large effect in the cell," Gelman said. "A change that makes a slightly less effective protein in the test tube can turn into a completely fatal mutation in the cell. First, the protein's role in the cell can no longer be fulfilled. Second, as more and more unfold, they can disrupt the function of the whole cell."-"The researchers think that the unfolded protein is likely to stick to nonchaperone molecules, as well, causing other problems in the cell and disrupting the flow within a cell. They plan to use the specialized microscope to study other proteins and how unfolding affects their diffusion, to see if the properties they observed are universal or if each protein has its own response."-And I keep asking the same question. If Darwin knew this when cellular protoplasm was considered to be just a blob, would he have considered evolution as a totally natural process?

Cell complexity: cell division control

by David Turell @, Wednesday, December 10, 2014, 19:15 (3423 days ago) @ David Turell

"Professor Iain Hagan, who leads the Cell Division group that carried out the research, said: "In particular, we wanted to find out the role played by three molecules, known as Protein Phosphatase 1, 2A-B55 and 2A-B56."-"Phosphatases are enzymes that remove phosphate groups from molecules, leading to a change in the molecule's activation and its control of cellular activity. They act in opposition to kinases, which add phosphate groups and are known to be over-active in some cancers.-"PP1 and PP2A account for 95% of all of the phosphatase activity of a human cell and had previously been assumed to be unlinked enzymes with a discrete set of functions.-"The group looked at the activity of the three phosphatases and found that PP1 was the master regulator that controlled the timing of the successive activation of each PP2A. This molecular 'tag team' coordinated the yeast cell's progression through the different steps in mitosis.-"Much of this process is conserved throughout all mammalian cells, which means that our studies in yeast will give us greater insight into cell division, and indeed overall cellular communication, in humans," added Professor Hagan."-
 Read more at: http://phys.org/news/2014-12-molecular-tag-team-revealed-cell.html#jCp

Cell complexity: enzyme heat control

by David Turell @, Wednesday, December 10, 2014, 19:22 (3423 days ago) @ David Turell

"Proteins are essential to the human body, doing the bulk of the work within cells. Proteins are large molecules responsible for the structure, function, and regulation of tissues and organs. Enzymes—special proteins that catalyze chemical reactions within cells—are critical to every bodily function from breathing to walking. Some enzymes produce a lot of heat per reaction. Enough heat, in fact, that if that heat were to be injected in another protein, that protein would overheat and unfold. So, how do enzymes expel that heat without overheating and self-destructing?-"Pressé explains, enzymes respond to the energy released during catalytic reactions by expanding and contracting which in turn violently propels the enzyme and generates a pressure wave—the study authors call it a chemoacoustic wave—because it is caused by the heat of a chemical reaction.-"Think of proteins as stepping on landmines. We asked how does a protein avoid damage from the enormous amounts of heat released and not break apart? Now we have shown that they cope with this heat assault by pushing that energy outwards from the reaction site as chemoacoustic waves and propelling themselves away in the meanwhile," said Pressé."-
 Read more at: http://phys.org/news/2014-12-proteins-landmines-survive-immense.html#jCp-How much more complexity do I have to show the reader before one is very impressed that this is not likely to have been the result of chance events.

Cell complexity: ion channels

by David Turell @, Friday, December 12, 2014, 14:28 (3422 days ago) @ David Turell

Cell membranes have pores which control thee in an out flow of ions, atoms without one electron. The body runs on 'wet electricity' different than the dry electricity of a computer. It takes extremely complex systems to do this.-http://darwins-god.blogspot.com/2014/12/potassium-channels-even-more-clever.html-"These positively charged ions enter and exit the cell via huge protein machines called channels which are imbedded in the cell wall and, like a donut, have a hole in the middle through which the ions flow. What is astonishing is how well these channels work. Not only do they open and close as needed, but they have two seemingly impossible design features. On the one hand they are extremely selective, allowing only a particular type of ion to flow through it. But on the other hand, they allow the chosen ions to flow through incredibly fast. It would seem that high selectivity would come at the cost of a slow transmission rate. But no, potassium channels for instance filter out practically everything but potassium ions, and yet their flow rate is practically at the maximum speed that is physically attainable. Now a recent study has added more information about how potassium channels perform their amazing feats."-
"Ion channels are proteins that line holes in the plasma membrane. They can open on demand to let ions in and out of the cell. They allow nerve impulses to travel, cause your heart to beat, and allow your muscles to contract. In many cells, channels and another kind of protein called a pump together maintain a relatively constant negative charge within your cells. This net negative charge, or membrane potential, affects the entry and exit of a variety of materials. page 15 of Bioinformatics, Genomics, and Proteomics: Getting the Big Picture-"10 million to 100 million per second!-
"The importance of these precise structures and hence functioning of protein machines like these channels cannot be understated. Potassium channels, like other channels that pass other ions from one side of the cell membrane to the other, have a particular architecture that allows them to open and close upon command. We now know that intricately designed and mechanically fine-tuned ion channels determine the rhythm and allow an electrical impulse initiated when we stub our toe to be transmitted to the brain.- Ibid page 19-"However even these, in comparison to electrons, huge ions also get lost in the wet environment. So what is needed are pumps along the way to pump ions in and also out. In the case of our nerve cells, ions go in to start the signal and are pumped out to reset that part of the system so it is ready for the next (or continuing) sensation."-http://www.uncommondescent.com/intelligent-design/potassium-channels-even-more-clever-than-thought/-Our entire body runs this way, and these descriptions are only a tiny part of the picture.

Cell complexity: nucular pores

by David Turell @, Friday, December 12, 2014, 18:00 (3422 days ago) @ David Turell

These are for molecules entering and exiting the nucleus. It is a protective feedback mechanism. In biologic processes, there is always a control feedback molecular mechanism.-http://www.the-scientist.com//?articles.view/articleNo/41507/title/Nuclear-Pore-QA/-"The surveillance
 Conducting genetic assays in yeast, Lusk's group identified the ESCRT-III complex as responsible for monitoring nuclear pore assembly and clearing malformed complexes. ESCRTs are known to bend membranes and assist in endocytosis and cytokinesis, so it's not terribly surprising that they also patrol a process that impacts the double membrane of the nuclear envelope, says Lusk. These are also ancient machineries—present since the last common eukaryotic ancestor—and as such “have been repurposed throughout the cell,” he says.-"The dump
 If the surveillance process fails and defective complexes arise, the yeast cell's means of dealing with them is to lump them into a compartment of the nuclear envelope that Lusk's group dubbed the SINC, for storage of improperly assembled nuclear pore complexes. Locking them up ensures that daughter cells don't inherit subpar nuclear pores."-And we are still unravelling the complexity of how a cell works. The answer is to expect the known complexity to get worse, or better, however it is viewed. And, of course, Darwin's mutations did this with careful advanced planning.

Cell complexity: a new book

by David Turell @, Wednesday, December 17, 2014, 15:38 (3417 days ago) @ David Turell

A study of how the eukaryote cell might have evolved:-http://phys.org/news/2014-12-eukaryotic-cell-ii-cytoskeleton.html

Cell complexity: a new book

by David Turell @, Wednesday, December 17, 2014, 15:58 (3417 days ago) @ David Turell

Another website with the same story:-http://www.the-scientist.com//?articles.view/articleNo/41511/title/The-Cellular-Revolution/-"When and precisely how the myriad internal structures that define the eukaryotic cell itself arose from simpler prokaryotic forms is much less obvious. The traditional view is that the nucleus, internal cytoskeleton, and other complex features arose in a stepwise fashion before the engulfment of the bacterium that was to become the mitochondrion. An increasingly popular alternative is that eukaryotic cellular complexity arose contemporaneously with the mitochondrion, powered by its novel metabolic capacities.-"Which of these two scenarios is closer to the truth is not yet clear. What we know is that endosymbiosis has had a profound impact on the course of evolution. Complex cells probably wouldn't have evolved without it; multicellular animals could not have arisen without the oxygen liberated by algal chloroplasts; and we wouldn't be here to ask big questions of the world around us."

Cell complexity: tubulin activity and microtubules

by David Turell @, Thursday, January 01, 2015, 21:40 (3401 days ago) @ David Turell

Learning all of the intricacies of cellular function and the role of microtubules:-"The flexibility of tubulin and the consequent versatility of its self-assembly can hardly be an accident. We propose that the polymorphism of assembly unique to tubulin reflects an exquisite tuning mechanism for the complex interaction of different microtubule intermediates with cellular factors that need to detect or make direct use of the growing or shortening state of microtubules to play functional roles at the right time and place in the cell. The characterization of the molecular interplay between tubulin polymers and cellular factors that affect tubulin assembly and/or are able to select tubulin polymerization states has only just begun, and promises to create new paradigms of microtubule cellular function, where tubulin polymers are not seen as passive platforms but as molecular machines capable of work by switching conformational and polymerization states." (my bold)-http://cryoem.berkeley.edu/microtubules-Of course designed by chance.

Cell complexity: dynein movement explained

by David Turell @, Tuesday, January 13, 2015, 00:49 (3390 days ago) @ David Turell

Kinesin and dynein move cargo in cells along microtubules. Kinesin movment is understood, but dynein is still being fully studied:-"They showed that two specific amino acid residues on the microtubule structure, R403 and E416, are key to turning on the switch that is critical for the activation of the dynein motor—demonstrating that when mutations in these sequences are present, the dynein fails to achieve directional movement on the microtubule, ending up simply moving back and forth in a random fashion. This lends weight to the idea, that has been generally accepted, that the motion of molecular motors is basically driven by random, Brownian motion, and that motors are able to move in one direction thanks to subtle changes in the strength of bonds at the motor-microtubule interface.-"Additionally, the group discovered that turning on the mechanical switch at the motor-microtubule interface leads to ATP hydrolysis. Their results altogether indicate that the subtle structural changes in the bonds at the interface are transmitted through a small change in the structure of the stalk—there are two coils that link the two binding regions, and a small shift in the configuration of the coils gives the cue for ATP hydrolysis at the ATP binding site."-
 Read more at: http://phys.org/news/2015-01-revealing-molecular-motor.html#jCp-These transport molecules literally walk along the tubules to carry cargo from one part of the cell to another. Just like a factory assembly line. God got there first before Henry Ford.

Cell complexity: control of RNA

by David Turell @, Monday, January 19, 2015, 14:30 (3384 days ago) @ David Turell

Cell complexity just developed by chance:-"Each cell is a busy warehouse of activity. To keep things orderly, protein workers are "assigned" to specific areas of the cell where other workers are collaborating on the same project. Most of the project areas, or organelles, in the cell are cordoned off by flexible membranes that let things in and out on an as-needed basis, but some organelles, like RNA granules, do not seem to have clear boundaries.-"RNA granules float throughout the watery space inside the cell and are responsible for transporting, storing and controlling RNA—DNA's chemical cousin—which holds blueprints for proteins. Until now, researchers thought that the granules didn't have concrete edges to separate them from the space outside.-"Before, the thinking was that RNA granules were like oil in water," says Geraldine Seydoux, Ph.D., a Howard Hughes investigator and professor of molecular biology and genetics at the Johns Hopkins University School of Medicine. "Oil molecules create droplets because they are attracted to themselves, and so they are able to separate from surrounding water. Now we know that the separation of RNA granules from their watery surroundings is facilitated by a dynamic envelope that stabilizes them.""-
 Read more at: http://phys.org/news/2015-01-cells_1.html#jCp

Cell complexity: membrane ingestion

by David Turell @, Monday, January 19, 2015, 15:34 (3384 days ago) @ David Turell

How the membrane ingests is only partially known:-"Their new study, published in Nature Communications, shows that the threshold at which proteins succeed at making a vesicle depends on both the quantity of membrane-bending proteins and the tension in the membrane itself. As tension on the membrane decreases, fewer proteins are needed to reach that critical mass.-"Calculating where this threshold is in a given cell would be useful for understanding many biological processes. Many diseases disrupt normal endocytosis, so altering this threshold might prove to be a basis for future treatments. -"This relationship between protein activity and membrane tensions may also help explain the recently discovered "ultrafast endocytosis" pathway, in which cells are sometimes able to form a vesicle in a few milliseconds, thousands of times faster than usual." -
 Read more at: http://phys.org/news/2015-01-relationship-critical-cells-ingest.html#jCp

Cell complexity: enzyme complexity

by David Turell @, Tuesday, May 12, 2015, 00:02 (3271 days ago) @ David Turell

The complexity of enzymes that control cell construction is amazing. How did they develop?-"The new structure provides crucial information for understanding how the protein binds to cellular components. It's also the first structure determined of any ligase in the tubulin tyrosine ligase-like (TTLL) family.-"Scientists have been especially curious about the role of TTLLs because mutations in these proteins have been linked to a range of neurodegenerative diseases, including retinal dystrophy and the rare Joubert syndrome.-"'This protein is highly expressed in the nervous system and has an integral role in neuronal development," said Elizabeth Wilson-Kubalek, senior staff scientist in Professor Ron Milligan's laboratory at TSRI." -
 Read more at: http://phys.org/news/2015-05-enzyme-important-nervous-health.html#jCp

Cell complexity: liquid phase separation

by David Turell @, Tuesday, October 06, 2015, 20:39 (3123 days ago) @ David Turell

Oil and water don't mix, but they do in cells:-http://www.sciencedaily.com/releases/2015/09/150924142855.htm-"Proteins are long strings of amino acids that usually fold into specific 3-D structures. hnRNPA1 belongs to a subset of proteins with an amino acid arrangement that prevents folding of one end of the protein, which allows hnRNPA1 to adopt a variety of conformations.-"In this study, researchers showed that under certain conditions related to temperature, salt and protein concentrations, hnRNPA1's disordered tail prompts the protein to condense into liquid droplets through a process called liquid phase separation. The droplets have properties similar to stress granules, including the ability to fuse and grow.-"Liquid phase separation is at work in a wide range of settings, including when oil and vinegar separate in salad dressing. Until recently, however, the process was not believed to play a role in normal cell function. This study is the first to link liquid phase separation to stress granule assembly.-"'It is amazing to find out that proteins like hnRNPA1 have appeared in nature to mediate liquid phase separation under normal physiological conditions," Mittag said. "The long disordered tails in these proteins enable membrane-less compartmentalization in cells. In addition, liquid phase separation is probably important for a whole range of fundamental biological processes.'"-Comment: More and more complexity

Cell complexity: sensing leucine

by David Turell @, Thursday, October 08, 2015, 18:10 (3122 days ago) @ David Turell

Cells work automatically with molecular actions in sequences. One such sequence is being worked out now:-http://phys.org/news/2015-10-scientists-essential-amino-acid-sensor.html-"Whitehead Institute scientists have at last answered the long-standing question of how the growth-regulating pathway known as mechanistic target of rapamycin complex 1 (mTORC1) detects the presence of the amino acid leucine—itself a key player in modulating muscle growth, appetite, and insulin secretion. Through a series of protein-mediated signals, mTORC1 interprets cues in the cellular environment, including nutrient availability, and instructs the organism to react accordingly. mTORC1 is apt to trigger growth during abundant times and slow metabolism when food is limited. Over the past several years, researchers in the lab of Whitehead Member David Sabatini have been identifying the many key components of the pathway—whose deregulation is associated with diseases ranging from diabetes to cancer to epilepsy—moving ever closer to finding precisely how mTORC1 actually senses the presence of amino acids.-"Earlier this year, Sabatini's group identified the transmembrane protein SLC38A9 as a putative sensor for arginine, but the sensor for leucine had remained elusive. Now, however, the lab has discovered that Sestrin2—one of a three-member protein family Sabatini previously implicated in amino acid detection—is a highly specific leucine sensor. The finding is reported online this week in the journal Science.-"'We finally have the sensor," says Rachel Wolfson, a graduate student in the Sabatini lab and co-first author of the Science paper. "We've always wanted to find it because we've known that leucine is one of the most important amino acids for the (mTORC1) pathway."-"Wolfson and co-first author Lynne Chantranupong, both of whom were involved in the earlier Sestrin research, found that in the absence of amino acids, Sestrin2 interacts with a protein complex known as GATOR2 to inhibit the mTORC1 pathway, thereby reducing cell growth. They then discovered that leucine binds directly to Sestrin2, disrupting the interaction and activating the mTORC1 pathway.-"'This was a big surprise for us, that there's an amino acid interaction with GATOR2 that's specific for leucine," says Chantranupong, also a graduate student in Sabatini's lab. "This is the first instance of a sensor for leucine, and there may be ways we might be able to take advantage of Sestrin2's leucine binding properties.'"-Comment: And all of this is run by information in the genome. See the video I presented today

Cell complexity: speed of reactions

by David Turell @, Friday, October 09, 2015, 22:31 (3120 days ago) @ David Turell

One cell is packed with millions of molecules all reacting in split-second timing:-http://www.sciencedaily.com/releases/2015/10/151009083201.htm-"Inside cells, communication between the nucleus, which harbours our precious genetic material, and the cytoplasm is mediated by the constant exchange of thousands of signaling molecules and proteins. Until now, it was unknown how this protein traffic can be so fast and yet precise enough to prevent the passage of unwanted molecules. Through a combination of computer simulations and various experimental techniques, researchers from Germany, France and the UK have solved this puzzle: A very flexible and disordered protein can bind to its receptor within billionths of a second. -***-"Unexpectedly, they found that flexible, spaghetti-like proteins can be good -- maybe even better than solid protein blocks -- at being recognised by multiple partners. And they can do so very fast, while still retaining the high specificity the cell needs. In fact, this could be why these disordered molecules are more common in evolutionarily higher organisms, the researchers surmise.-"Researchers had assumed that when an IDP 'key' needed to bind to its lock, it rearranged itself to become more rigid, but experiments in the Lemke lab hinted otherwise. "The pioneering single molecule experiments undertaken at EMBL showed for the particular interaction of a receptor with a disordered protein just nothing: the flexible protein stayed as flexible even when bound to its receptor" says Davide Mercadante (HITS). This prompted him to study the very same interaction on the computer. The surprising result was that the high flexibility of the IDP actually helps it bind to its lock -- in this case, a nuclear transport receptor, which shuttles proteins into the nucleus. The simulations even suggested the binding to be ultrafast -- faster than any other association of that kind recorded to date. "The computational data indicated that we might have identified a new ultrafast binding mechanism, but it took us three years to design experiments to prove the kinetics in the lab," Iker Valle Aramburu (EMBL) recalls. "In the end, we had a remarkably perfect match."-***- "'Our findings explain the so-called transport paradox -- that is, how this shuttling can be so very fast while remaining specific so that unwanted molecules cannot pass the barrier that protects our genome." The new study suggests that many binding motifs at the surface of the IDP create a highly reactive surface that together with the very high speed of locking and unlocking ensures efficient proof-reading while the receptors to travel so fast through a pore filled with other IDPs."-Comment: Automatically accurate, or death. That should be obvious. I don't see a thought process here.

Cell complexity: speed of reactions

by dhw, Saturday, October 10, 2015, 12:02 (3120 days ago) @ David Turell

DAVID: One cell is packed with millions of molecules all reacting in split-second timing:-Comment: Automatically accurate, or death. That should be obvious. I don't see a thought process here.-Then try this variation: one organism is packed with millions of cells all reacting in split-second timing. Add McClintock: “Every component of the organism is as much of an organism as every other part.”-The thought is what directs the cells of the organism, and the thought is what directs the molecules of the cell. The source of the thought that directs the cells and the molecules within the cells (each cell being an organism) is the inventive mechanism or “brain”.

Cell complexity: speed of reactions

by David Turell @, Saturday, October 10, 2015, 15:01 (3120 days ago) @ dhw


> David: Comment: Automatically accurate, or death. That should be obvious. I don't see a thought process here.
> 
> dhw: Then try this variation: one organism is packed with millions of cells all reacting in split-second timing. Add McClintock: “Every component of the organism is as much of an organism as every other part.”
> 
> The thought is what directs the cells of the organism, and the thought is what directs the molecules of the cell. The source of the thought that directs the cells and the molecules within the cells (each cell being an organism) is the inventive mechanism or “brain”.-If I could be shown an organelle of 'thought' I might accept your point. None exists.

Cell complexity: speed of reactions

by dhw, Sunday, October 11, 2015, 12:20 (3119 days ago) @ David Turell
edited by dhw, Sunday, October 11, 2015, 12:35

David: Comment: Automatically accurate, or death. That should be obvious. I don't see a thought process here.-dhw: Then try this variation: one organism is packed with millions of cells all reacting in split-second timing. Add McClintock: “Every component of the organism is as much of an organism as every other part.”
The thought is what directs the cells of the organism, and the thought is what directs the molecules of the cell. The source of the thought that directs the cells and the molecules within the cells (each cell being an organism) is the inventive mechanism or “brain”.-DAVID: If I could be shown an organelle of 'thought' I might accept your point. None exists.-I prefer the word ‘intelligence', since it is too tempting to equate ‘thought' with the multiple levels of consciousness involved in our own thinking. Like you and the rest of the world, I don't know how this is generated, though we would probably agree that it is somehow associated with the brain. Buehler thinks the cellular equivalent of the brain is the centrosphere:
 
Guenther Buehler and Cell intelligence - Home :...
www.basic.northwestern.edu/g-buehler/FRAME.HTM-QUOTE Centrosphere: Centrioles and radial array of microtubules. From the point of view of the ‘intelligent cell' the centrosphere is the ‘brain' of the cell. Analogous to our own bodies, it projects the ‘eyes' in the form of a pair of centrioles. Likewise, its ‘nerves' correspond to the radial array of microtubules connecting the centrospheres unbranchingly with the cellular ‘musculature' contained in the cortex. (Introduction: Anatomy of the intelligent cell)-Of course you will reject this, as you reject the findings of all other proponents of cellular intelligence, but since there is apparently a 50/50 chance that they are right, there must also be a chance that after 30-plus years of research he might be onto something. "None exists" seems a bit strong when it's 50/50.

Cell complexity: speed of reactions

by David Turell @, Sunday, October 11, 2015, 14:56 (3119 days ago) @ dhw

dhw: Buehler thinks the cellular equivalent of the brain is the centrosphere:
> 
> Guenther Buehler and Cell intelligence - Home :...
> www.basic.northwestern.edu/g-buehler/FRAME.HTM
> 
> QUOTE Centrosphere: Centrioles and radial array of microtubules. From the point of view of the ‘intelligent cell' the centrosphere is the ‘brain' of the cell. Analogous to our own bodies, it projects the ‘eyes' in the form of a pair of centrioles. Likewise, its ‘nerves' correspond to the radial array of microtubules connecting the centrospheres unbranchingly with the cellular ‘musculature' contained in the cortex. (Introduction: Anatomy of the intelligent cell)-Snipped out what you like in a quote mine. Not a full view of what Buehler admits:-"Yet, the vast majority of today's biologists devote their efforts to prove the opposite, namely that specific molecular interactions create the cellular functions such as cell division, directed locomotion, differentiation, design of the extracellular matrix, adhesion to materials and other cells and so forth." -Note 'vast majority'. He is the outlier in thought, and you wish to lay with him.
> 
> dhw: Of course you will reject this, as you reject the findings of all other proponents of cellular intelligence, but since there is apparently a 50/50 chance that they are right, there must also be a chance that after 30-plus years of research he might be onto something. "None exists" seems a bit strong when it's 50/50.-Note this statement of his:-"As summarized in this web site, it presents novel assays demonstrating that cells coordinate their bodies during movement and respond to physical and topological parameters which are too weak to have caused the observed reaction by force. These responses are then analyzed and used to identify the nature and location of a cellular data-integration system that may be responsible for these actions."-Of course there is a 'data integration system'. All built-in or the cells wouldn't survive. Look at the illustrated videos of cellular components in action. All from intelligent information in the genome. -Note: He is retired honorably, and not quoted widely in all of the material I have surveyed over 30 years of reading about this. And I've read the stuff I've given you to quote against me.

Cell complexity: speed of reactions

by dhw, Monday, October 12, 2015, 12:58 (3118 days ago) @ David Turell
edited by dhw, Monday, October 12, 2015, 13:18

dhw: Buehler thinks the cellular equivalent of the brain is the centrosphere:-QUOTE: Centrosphere: Centrioles and radial array of microtubules etc.-DAVID: Snipped out what you like in a quote mine. Not a full view of what Buehler admits:
"Yet, the vast majority of today's biologists devote their efforts to prove the opposite, namely that specific molecular interactions create the cellular functions such as cell division, directed locomotion, differentiation, design of the extracellular matrix, adhesion to materials and other cells and so forth." 
Note 'vast majority'. He is the outlier in thought, and you wish to lay with him.-I “snipped out” the quote, because you asked to be shown an “organelle” of thought. There are many eminent biologists who support the concept of the intelligent cell, and you have agreed that the chances are 50/50. I do not wish to “lay with him”, but plead for an open mind on the subject. As for the “vast majority”, how many biologists do you think would agree with you that God designed 3.8 billion years' worth of evolution in order to produce or feed humans? I suspect you don't care. Nor in respect of the “intelligent cell” do/did Buehler, McClintock, Margulis, Shapiro & Co.
 
DAVID: Note this statement of his:
"As summarized in this web site, it presents novel assays demonstrating that cells coordinate their bodies during movement and respond to physical and topological parameters which are too weak to have caused the observed reaction by force. These responses are then analyzed and used to identify the nature and location of a cellular data-integration system that may be responsible for these actions."
Of course there is a 'data integration system'. All built-in or the cells wouldn't survive. Look at the illustrated videos of cellular components in action. All from intelligent information in the genome.-The whole point of his research and his book (look at the title!) is that the data integration system is an intelligent “brain”, not a machine. In his experiments, he has observed unforced responses, which I take to mean responses that require decisions as opposed to offering only one option. That is how one can tell the difference between automatic and autonomous behaviour. 50/50?
 
DAVID: Note: He is retired honorably, and not quoted widely in all of the material I have surveyed over 30 years of reading about this. And I've read the stuff I've given you to quote against me.-The fact that like yourself he has now retired "honorably", you didn't know his work, and it is not quoted widely proves absolutely nothing. His conclusions tie in with those drawn by biologists who ARE quoted widely. And the fact that you have given me material to quote against you does not invalidate the conclusions of the scientists you took it from.

Cell complexity: speed of reactions

by David Turell @, Monday, October 12, 2015, 14:18 (3118 days ago) @ dhw

dhw: The fact that like yourself he has now retired "honorably", you didn't know his work, and it is not quoted widely proves absolutely nothing. His conclusions tie in with those drawn by biologists who ARE quoted widely. And the fact that you have given me material to quote against you does not invalidate the conclusions of the scientists you took it from.-Again, he recognized he is in a small minority of thought, and you wish to be with him: -" David: Not a full view of what Buehler admits:
 "Yet, the vast majority of today's biologists devote their efforts to prove the opposite, namely that specific molecular interactions create the cellular functions such as cell division, directed locomotion, differentiation, design of the extracellular matrix, adhesion to materials and other cells and so forth." (my bold)

Cell complexity: speed of reactions

by dhw, Tuesday, October 13, 2015, 12:00 (3117 days ago) @ David Turell
edited by dhw, Tuesday, October 13, 2015, 12:09

dhw: The fact that like yourself he [Buehler] has now retired "honorably", you didn't know his work, and it is not quoted widely proves absolutely nothing. His conclusions tie in with those drawn by biologists who ARE quoted widely. And the fact that you have given me material to quote against you does not invalidate the conclusions of the scientists you took it from.-DAVID: Again, he recognized he is in a small minority of thought, and you wish to be with him: 
" David: Not a full view of what Buehler admits:
"Yet, the vast majority of today's biologists devote their efforts to prove the opposite, namely that specific molecular interactions create the cellular functions such as cell division, directed locomotion, differentiation, design of the extracellular matrix, adhesion to materials and other cells and so forth." (my bold)
-I replied to this already:-I do not wish to “lay with him”, but plead for an open mind on the subject. As for the “vast majority”, how many biologists do you think would agree with you that God designed 3.8 billion years' worth of evolution in order to produce or feed humans? I suspect you don't care. Nor in respect of the “intelligent cell” do/did Buehler, McClintock, Margulis, Shapiro & Co.-I would add that the conclusions of these scientists are based on their studies of cellular behaviour, you yourself have agreed that there is a 50/50 chance of their being right, and devoting one's efforts to proving something is not the same as proving it - an argument that cuts both ways, of course. So keep an open mind.

Cell complexity: speed of reactions

by David Turell @, Tuesday, October 13, 2015, 14:11 (3117 days ago) @ dhw


> dhw: I would add that the conclusions of these scientists are based on their studies of cellular behaviour, you yourself have agreed that there is a 50/50 chance of their being right, and devoting one's efforts to proving something is not the same as proving it - an argument that cuts both ways, of course. So keep an open 
mind.-Pulling rank: As a medical physician, trained in understanding how cells work in the human body, and presuming logically that they have the same automatic attributes in single-celled organisms, I won't change.

Cell complexity: speed of reactions

by dhw, Wednesday, October 14, 2015, 12:07 (3116 days ago) @ David Turell

dhw: I would add that the conclusions of these scientists are based on their studies of cellular behaviour, you yourself have agreed that there is a 50/50 chance of their being right, and devoting one's efforts to proving something is not the same as proving it - an argument that cuts both ways, of course. So keep an open mind.-DAVID: Pulling rank: As a medical physician, trained in understanding how cells work in the human body, and presuming logically that they have the same automatic attributes in single-celled organisms, I won't change.-You can pull rank on me with all your presumptions, but not on the professional biologists who disagree with you. One of them won the Nobel Prize for her discovery of genetic transposition, so try pulling rank on her.

Cell complexity: speed of reactions

by David Turell @, Wednesday, October 14, 2015, 15:17 (3116 days ago) @ dhw


> DAVID: Pulling rank: As a medical physician, trained in understanding how cells work in the human body, and presuming logically that they have the same automatic attributes in single-celled organisms, I won't change.
> 
> dhw: You can pull rank on me with all your presumptions, but not on the professional biologists who disagree with you. One of them won the Nobel Prize for her discovery of genetic transposition, so try pulling rank on her.-Like I said previously, you fell for her hyperbole.

Cell complexity: speed of reactions

by dhw, Thursday, October 15, 2015, 11:41 (3115 days ago) @ David Turell

DAVID: Pulling rank: As a medical physician, trained in understanding how cells work in the human body, and presuming logically that they have the same automatic attributes in single-celled organisms, I won't change.-dhw: You can pull rank on me with all your presumptions, but not on the professional biologists who disagree with you. One of them won the Nobel Prize for her discovery of genetic transposition, so try pulling rank on her.-DAVID: Like I said previously, you fell for her hyperbole.-Her conclusion, like that of Margulis, Shapiro, Buehler and others, is perfectly straightforward: cells are sentient, cognitive, intelligent beings in their own right. There is no hyperbole. Either these researchers are right or they are wrong. Like you said previously, 50/50.

Cell complexity: speed of reactions

by David Turell @, Friday, October 16, 2015, 01:19 (3114 days ago) @ dhw


> DAVID: Like I said previously, you fell for her hyperbole.
> 
> dhw: Her conclusion, like that of Margulis, Shapiro, Buehler and others, is perfectly straightforward: cells are sentient, cognitive, intelligent beings in their own right. There is no hyperbole. Either these researchers are right or they are wrong. Like you said previously, 50/50.-So be it.

Cell complexity: liquid phase separation

by David Turell @, Tuesday, November 27, 2018, 00:00 (1976 days ago) @ David Turell

A newer article with new discoveries:

https://www.quantamagazine.org/

"Think of liquids with different properties that don’t really mix but, under specific circumstances, cluster and separate like the shifting blobs in a lava lamp. That phenomenon, also known as liquid-liquid phase separation, was once considered to be an exclusively chemical process. But less than a decade ago, Brangwynne became one of the first to observe it happening inside cells as well, and ever since then, biologists have been trying to learn its significance.

"Now scientists are beginning to understand that evolution has tuned certain proteins to act in aggregate like liquids. Through phase separation, they spontaneously self-assemble into dynamic, membrane-free, dropletlike structures that can perform needed tasks in cells.

***

"One of the latest findings is that phase separation allows certain types of cells to cheat death when they are deprived of nutrients or otherwise put under stress. Phase separation enables the cells to turn a large part of their cytoplasm from a liquid to a solid — essentially putting themselves into a hardy condition of stasis until the nutrients return.

***

"That initial work by Brangwynne, Eckmann and Hyman triggered an avalanche of papers investigating the assembly and dispersal of various cytoplasmic proteins under various conditions. The evidence was getting stronger that cells had evolved a fine-tuned mechanism for organizing some of their internal structure and processes through phase separation — that is, letting proteins self-assemble into structures that could perform distinct functions.

***

"Zaburdaev and several of his colleagues, including Alberti, decided to check what happens to proteins when cells are subjected to stresses such as falling temperatures and the sudden disappearance of nutrients. The surprising result they uncovered was that phase separation can be part of a cell’s survival mechanism.

"The cells’ behavior could be likened to hibernation for bears. The animal lays still in a dormant state for weeks, minimizing its expenditure of energy. At a cellular level, phase separation helps the gelatinous cytoplasm make a protective transition into something more solid. “In this ‘solidified’ state, a cell can survive starvation,” Zaburdaev said.

***

"Simply by varying the acidity of the [yeast] cells’ environment, the scientists could induce them to switch into this survival state, even without taking away the cells’ nutrients. The cells could rest this way for hours or even days. “We found that the cells are so rigid that they keep their shape” instead of being deformable, Alberti said. They “transition into a completely different material state.”

"When their normal pH was later restored, the cells returned to normal, “dividing and living happily,” Zaburdaev said.

***

"The team found that when a protein has a certain identifiable domain or region, the protein will form easily reversible gels. In the absence of this domain, the protein forms an irreversible type of assembly — permanently removing it from further use.

"In effect, this domain modifies the protein’s phase behavior and keeps it reusable. “The domain provides a new possibility, for that protein to assemble into a benign kind of gel and not something from which you cannot come back,” Alberti said.

***

"Such results imply that nature has designed the domain sequences to tune the proteins’ material properties.

***

"Recently, for example, the neuroscientist Pietro De Camilli at Yale University and his colleagues found evidence that phase separation might be involved in the controlled release of neurotransmitters at synapses. It had been observed that vesicles containing neurotransmitters routinely hover in clusters near the presynaptic membrane until they are needed. De Camilli’s team showed that a scaffolding protein called synapsin 1 condenses into a liquid phase, along with other proteins, to bind the vesicles into these clusters. When the synapsin is phosphorylated, the droplet rapidly dissipates and the vesicles are freed to spill the neurotransmitters into the synapse."

Comment: Other than the neurological finding directly above, this is yeast research, and how it applies to multicellular organisms is not known. But what is seen at the single cell stage is usually finally found in complex organisms. Too complex for any mechanism than design of specific proteins with this property .

Cell complexity: liquid phase separation

by David Turell @, Friday, November 30, 2018, 00:19 (1973 days ago) @ David Turell

More on this new study:

https://phys.org/news/2018-11-tools-illuminate-mechanisms-overlooked-cellular.html

"Creating new tools that harness light to probe the mysteries of cellular behavior, Princeton researchers have made discoveries about the formation of cellular components called membraneless organelles and the key role these organelles play in cells.

"The tools developed by the researchers allow scientists to accurately probe intracellular phase separation—the process by which the chaotic liquid matter inside cells transforms into functioning cellular compartments called membraneless organelles.

"Long overlooked, these organelles have been shown to play critical roles in human health. The loss of their fluid-like consistency, for instance, is implicated in diseases including cancer, Alzheimer's, and amyotrophic lateral sclerosis (ALS). Previous work in Brangwynne's lab has shown the membraneless organelles play an important role in cell growth. And one of the two recent Cell papers demonstrates they also influence the genes controlling cellular behavior.

***

"...the researchers examine how the formation of membraneless organelles affects the cell's nucleus. Using a second tool, named CasDrop, the researchers looked at chromatin, the mixture of DNA, RNA and protein inside the nucleus. They found that as membraneless organelles form within the nucleus, they deform the chromatin in unexpected ways. They showed that the droplets push out unwanted genes, but can simultaneous pull together specifically targeted genes. The droplets can thus function like little, mechanically-active machines to restructure the genome. (my bold)

"The CasDrop system builds on the revolutionary gene-editing technology called CRISPR, which utilizes a protein machine called Cas9, to address particular genes in the cell. Brangwynne and colleagues engineered Cas9 to function as a platform, which upon light activation causes other proteins to bind to the gene, and locally phase separate, forming little dew droplets on the field of chromatin."

Comment: Another layer of gene control involving a fascinating physical change in cells, liquid-liquid phase separation creating membraneless organelles! Amazing design requires a designing mind.

Cell complexity: DNA supply control enzyme complexity

by David Turell @, Wednesday, February 21, 2018, 01:48 (2255 days ago) @ David Turell

The structure of an enzyme that controls the supply of DNA parts for cell use has been outlined:

https://phys.org/news/2018-02-scientists-high-resolution-glimpse-enzyme.html

"Using a state-of-the-art type of electron microscopy, an MIT-led team has discovered the structure of an enzyme that is crucial for maintaining an adequate supply of DNA building blocks in human cells.

"Their new structure also reveals the likely mechanism for how cells regulate the enzyme, known as ribonucleotide reductase (RNR). Significantly, the mechanism appears to differ from that of the bacterial version of the enzyme,

***

"The RNR enzyme, which is found in all living cells, converts ribonucleotides (the building blocks of RNA) to deoxyribonucleotides (the building blocks of DNA). Cells must keep a sufficient stockpile of these building blocks, but when they accumulate too many, RNR is shut off by a deoxynucleotide molecule known as dATP. When more deoxynucleotides are needed, a related molecule called ATP binds to RNR and turns it back on.

"An unusual feature of RNR is that it can catalyze the production of four different products: the nucleotide bases often abbreviated as A, G, C, and T. In 2016, Drennan discovered that the enzyme achieves this by changing its shape in response to regulatory molecules.

***

"Using cryo-EM, the MIT team found that the human version of the enzyme forms a ring made from six of the alpha subunits. When ATP, which activates RNR, is bound to the enzyme, the ring is unstable and can be easily opened up, allowing the beta subunit to make its way into the ring. This joining of alpha and beta allows the enzyme's active site, located in the beta subunit, to perform the chemical reactions necessary to produce deoxynucleotides.

"However, when the inhibitor dATP is present, the ring becomes much more rigid and does not allow the beta subunit to enter. This prevents the enzyme from catalyzing the production of deoxynucleotides."

To see these complex structures look at the illustrations in this article:

https://elifesciences.org/articles/31502

Comment: The complexity of the structure and of the functions of this giant enzyme demands that a designer of life be strongly considered. Only a planning mind can create such structures with such precise mechanisms of function.

Cell complexity: they 'think' through chemical processes

by David Turell @, Saturday, May 05, 2018, 22:09 (2181 days ago) @ David Turell

The method used to analyze these chemical processes is through mathematics:

https://www.sciencedaily.com/releases/2018/05/180502094636.htm

"'I studied all the possible ways a network can be constructed and found that to be capable of this perfect adaptation in a robust way, a network has to satisfy an extremely rigid set of mathematical principles. There are a surprisingly limited number of ways a network could be constructed to perform perfect adaptation. (my bold)

"'Essentially we are now discovering the needles in the haystack in terms of the network constructions that can actually exist in nature.

"'Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to 'think' -- essentially giving the cell a 'cognitive' ability, or a 'brain'," she said. "It has been a longstanding mystery in science how this cellular 'brain' works.

"'We could never hope to measure the full complexity of cellular networks -- the networks are simply too large and interconnected and their component proteins are too variable.

"'But mathematics provides a tool that allows us to explore how these networks might be constructed in order to perform as they do.

***

"An example of perfect adaptation is our sense of smell," she said. "When exposed to an odour we will smell it initially but after a while it seems to us that the odour has disappeared, even though the chemical, the stimulus, is still present.

"'Our sense of smell has exhibited perfect adaptation. This process allows it to remain sensitive to further changes in our environment so that we can detect both very feint and very strong odours.

"'This kind of adaptation is essentially what takes place inside living cells all the time. Cells are exposed to signals -- hormones, growth factors, and other chemicals -- and their proteins will tend to react and respond initially, but then settle down to pre-stimulus levels of activity even though the stimulus is still there.

"'I studied all the possible ways a network can be constructed and found that to be capable of this perfect adaptation in a robust way, a network has to satisfy an extremely rigid set of mathematical principles. There are a surprisingly limited number of ways a network could be constructed to perform perfect adaptation.

"'Essentially we are now discovering the needles in the haystack in terms of the network constructions that can actually exist in nature.'"

Comment: this study fits exactly my concept of automatic molecular activity. The limited number of a 'rigid set of mathematical principles' describes this to a 'T'. this is like a cellular brain, as the author states, but because of superior design it becomes a brain equivalent. This is an answer to the Shapiro approach, and fits my knowledge of biochemistry.

Cell complexity: they 'think' through chemical processes

by dhw, Sunday, May 06, 2018, 12:31 (2181 days ago) @ David Turell

QUOTE: "'Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to 'think' -- essentially giving the cell a 'cognitive' ability, or a 'brain'," she said. "It has been a longstanding mystery in science how this cellular 'brain' works.”
“'We could never hope to measure the full complexity of cellular networks -- the networks are simply too large and interconnected and their component proteins are too variable”.

Thank you for this highly illuminating study. I'm sure you will have noted that these observations about “thinking through chemical processes” would apply to bacteria as well as to the cell communities which make up our own brain.

DAVID’s comment: this study fits exactly my concept of automatic molecular activity. The limited number of a 'rigid set of mathematical principles' describes this to a 'T'. this is like a cellular brain, as the author states, but because of superior design it becomes a brain equivalent. This is an answer to the Shapiro approach, and fits my knowledge of biochemistry.

I shan’t pretend to understand the science, but the implications are crystal clear. The cell has its equivalent of the brain, and “thought” is produced by complex networks of chemical reactions, i.e. in individual cells (bacteria) and in cell communities (the brain). At a single stroke, this article supports two of my hypotheses: 1) cells are intelligent; 2) intelligence emerges from materials. The third stage I have proposed in my “reconciliation” post is that this intelligence may be in the form of energy which can exist independently of the materials. (NB “may be” – I remain uncommitted.) You have agreed to this. Could it be, then, that we are moving towards consensus?

Cell complexity: they 'think' through chemical processes

by David Turell @, Sunday, May 06, 2018, 15:19 (2181 days ago) @ dhw

dhw: QUOTE: "'Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to 'think' -- essentially giving the cell a 'cognitive' ability, or a 'brain'," she said. "It has been a longstanding mystery in science how this cellular 'brain' works.”
“'We could never hope to measure the full complexity of cellular networks -- the networks are simply too large and interconnected and their component proteins are too variable”.

Thank you for this highly illuminating study. I'm sure you will have noted that these observations about “thinking through chemical processes” would apply to bacteria as well as to the cell communities which make up our own brain.

DAVID’s comment: this study fits exactly my concept of automatic molecular activity. The limited number of a 'rigid set of mathematical principles' describes this to a 'T'. this is like a cellular brain, as the author states, but because of superior design it becomes a brain equivalent. This is an answer to the Shapiro approach, and fits my knowledge of biochemistry.

dhw: I shan’t pretend to understand the science, but the implications are crystal clear. The cell has its equivalent of the brain, and “thought” is produced by complex networks of chemical reactions, i.e. in individual cells (bacteria) and in cell communities (the brain). At a single stroke, this article supports two of my hypotheses: 1) cells are intelligent; 2) intelligence emerges from materials. The third stage I have proposed in my “reconciliation” post is that this intelligence may be in the form of energy which can exist independently of the materials. (NB “may be” – I remain uncommitted.) You have agreed to this. Could it be, then, that we are moving towards consensus?

I see no agreement between us. The activities follow design patterns. As a result it is obvious they are all automatic chemical reactions, as they all mimic each other. All of the interlocking processes, controlling each other is most likely the way life appears and works.It does not require some sort of 'intelligence' at the controls because all the controls are intelligently designed in the processes themselves. Understanding the science tells me this.

Cell complexity: they 'think' through chemical processes

by dhw, Monday, May 07, 2018, 12:29 (2180 days ago) @ David Turell

QUOTE: "'Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to 'think' -- essentially giving the cell a 'cognitive' ability, or a 'brain'," she said. "It has been a longstanding mystery in science how this cellular 'brain' works.”
“'We could never hope to measure the full complexity of cellular networks -- the networks are simply too large and interconnected and their component proteins are too variable”.

dhw: I shan’t pretend to understand the science, but the implications are crystal clear. The cell has its equivalent of the brain, and “thought” is produced by complex networks of chemical reactions, i.e. in individual cells (bacteria) and in cell communities (the brain). At a single stroke, this article supports two of my hypotheses: 1) cells are intelligent; 2) intelligence emerges from materials. The third stage I have proposed in my “reconciliation” post is that this intelligence may be in the form of energy which can exist independently of the materials. (NB “may be” – I remain uncommitted.) You have agreed to this. Could it be, then, that we are moving towards consensus?

DAVID: I see no agreement between us. The activities follow design patterns. As a result it is obvious they are all automatic chemical reactions, as they all mimic each other. All of the interlocking processes, controlling each other is most likely the way life appears and works.It does not require some sort of 'intelligence' at the controls because all the controls are intelligently designed in the processes themselves. Understanding the science tells me this.

And I’m sure that “understanding the science” told/tells McClintock, Margulis, Bühler, Shapiro that communication, cognitive ability, a brain equivalent etc. denote intelligence and not automaticity. Thank you for presenting the evidence, even if we disagree on the conclusion!

Cell complexity: they 'think' through chemical processes

by David Turell @, Monday, May 07, 2018, 14:50 (2180 days ago) @ dhw

QUOTE: "'Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to 'think' -- essentially giving the cell a 'cognitive' ability, or a 'brain'," she said. "It has been a longstanding mystery in science how this cellular 'brain' works.”
“'We could never hope to measure the full complexity of cellular networks -- the networks are simply too large and interconnected and their component proteins are too variable”.

dhw: I shan’t pretend to understand the science, but the implications are crystal clear. The cell has its equivalent of the brain, and “thought” is produced by complex networks of chemical reactions, i.e. in individual cells (bacteria) and in cell communities (the brain). At a single stroke, this article supports two of my hypotheses: 1) cells are intelligent; 2) intelligence emerges from materials. The third stage I have proposed in my “reconciliation” post is that this intelligence may be in the form of energy which can exist independently of the materials. (NB “may be” – I remain uncommitted.) You have agreed to this. Could it be, then, that we are moving towards consensus?

DAVID: I see no agreement between us. The activities follow design patterns. As a result it is obvious they are all automatic chemical reactions, as they all mimic each other. All of the interlocking processes, controlling each other is most likely the way life appears and works.It does not require some sort of 'intelligence' at the controls because all the controls are intelligently designed in the processes themselves. Understanding the science tells me this.

dhw: And I’m sure that “understanding the science” told/tells McClintock, Margulis, Bühler, Shapiro that communication, cognitive ability, a brain equivalent etc. denote intelligence and not automaticity. Thank you for presenting the evidence, even if we disagree on the conclusion!

What we can agree upon is that intelligence is involved. Which makes the case for God stronger.

Cell complexity: talking through microtubules

by David Turell @, Tuesday, May 08, 2018, 00:28 (2179 days ago) @ David Turell

This is another way of communicating:

https://www.scientificamerican.com/article/cells-talk-and-help-one-another-via-tiny-tub...

"Finally, after delving into the literature, Lou realized that the lines matched what Hans-Hermann Gerdes’ group at the University of Heidelberg had described as “nanotubular highways” or “tunneling nanotubes” (TNTs) in a 2004 paper in Science.

***

"In the last few years, the number of researchers working on TNTs and figuring out what they do has risen steeply. Research teams have discovered that TNTs transfer all kinds of cargo beyond microRNAs, including messenger RNAs, proteins, viruses and even whole organelles, such as lysosomes and mitochondria.

"These fragile structures are appearing not only in the context of conditions such as cancer, AIDS and neurodegenerative diseases, but also in normal embryonic development. Healthy adult cells don’t usually make TNTs, but stressed or ailing cells appear to induce them by sending out signals to call for help. It’s unclear, though, how healthy cells sense that their neighbors need help or how they physiologically “know” what specific cargo to send.

***

"With microscopy techniques, the group examined the structures further and determined that they are open channels through which organelles and membrane vesicles move from one cell to another. At that point it became clear that the membrane tubes were “a completely new mechanism of cell-cell communication,” Rustom explained. It was not so easy, however, to convince others—some researchers suspected that these TNTs were experimental artifacts, not naturally occurring structures. It took the group four or five years to publish their paper because of the strong skepticism with which the findings were met, he said.

"Confirming that TNTs are indeed an avenue for intercellular communication has continued to be a major challenge. Cells have other options for exchanging molecules, most notably the structures called gap junctions and exosomes.

"If TNTs are akin to skywalks, the enclosed footbridges that connect separate buildings, then gap junctions—gated pores that pass through the membranes of neighboring cells—are like doorways between adjacent rooms. Exosomes, small vesicles shed by cells, were long thought to be cellular trash bags carrying debris, but scientists now recognize them as vehicles for carrying microRNAs and other signaling molecules between cells, sometimes over long distances. The challenge in identifying the role of TNTs is that it’s tricky to inhibit any one of these communication channels without interfering with the others.

***

"What complicates matters is that TNTs appear in a wide variety of cell types and are morphologically diverse, showing up in a wide range of sizes. In some cases they are large enough to be considered microtubes rather than nanotubes, and some researchers believe that the smaller TNTs are functionally different from microtubes. Efforts are ongoing to characterize the different subtypes of nano- and microtubes.

***

"Before his eyes, the mRNA molecules migrated through TNTs bridging the different cells. “I could actually see the mRNA is found in the membrane nanotubes, and that if I inhibit membrane nanotube formation … I abolish RNA transfer,” he said.

"To understand whether or not the cells actively regulate these transfers, Haimovich challenged them with heat shock and oxidative stress. If changes in the environmental conditions changed the rate of RNA transfer, that “would suggest that this is a biologically regulated mechanism, not just diffusion of RNA by chance,” he explained. He found that oxidative stress did induce an increase in the rate of transfer, while heat shock induced a decrease. Moreover, this effect was seen if stress was inflicted on acceptor cells but not if it was also inflicted on donor cells prior to co-culture, Haimovich clarified by email. “This suggests that acceptor cells send signals to the donor cells ‘requesting’ mRNA from their neighbors,” he said."

Comment: They certainly do communicate, if mRNA can be see travelling down the tubules. This adds to the complexity of intercellular communication. Not by chance.

Cell complexity: stimulus causes protein signalling

by David Turell @, Tuesday, May 08, 2018, 00:51 (2179 days ago) @ David Turell

This study unravels how cells respond to stimuli through a 'tail' on an protein molecule:

https://phys.org/news/2018-05-uncovering-hidden-protein-tail-cell.html

"..researchers have found a previously-unknown mechanism that puts the brakes on an important cell signaling process involving the G proteins found in most living organisms.

"The mechanism, dubbed a "tail," is part of a small protein known mostly for its role in attaching larger structures to the cell membrane. When researchers inactivated the tail, a signaling response that had previously taken 30 minutes to occur happened almost immediately - with an intensity four times greater than normal.

***

"We have discovered the mechanism that regulates how quickly a pathway gets turned on by an external stimulus," said Matthew Torres, an associate professor in the School of Biological Sciences at the Georgia Institute of Technology. "By genetically altering the control mechanism underlying this process, we are able to modulate how much of a signal from outside the cell gets inside the cell and how quickly it gets through. It's all the more astonishing because this mechanism has been hiding in plain sight for decades."

"G proteins, also known as guanine nucleotide-binding proteins, are a family of molecules that operate as molecular switches inside cells. They transmit signals acquired from a variety of extracellular stimuli to the interior of a cell - through the membrane, which otherwise wouldn't allow communication.

"The tail found by Torres and Doctoral Candidate Shilpa Choudhury likely escaped attention because it is flexibly attached to the G protein gamma subunit of a closely-collaborating protein team known as G beta/gamma. Protein structures have generally been identified by X-ray crystallography techniques which cannot resolve structures that are in motion.

"Prior to their work, the G gamma subunit has been known primarily as the protein that connects the larger G beta subunit to the cell membrane. Without the work of SAPH-ire - an informatics program that maps PTM activity using machine learning - the role of the tail structure might not have been identified.

"In yeast, G beta/gamma subunits activate a signaling pathway in response to pheromones, a process which normally takes about 30 minutes after stimulation of a pheromone receptor at the cell membrane. Torres and Choudhury suspected that protein modifications, PTMs, were somehow causing the delay. Their computer program SAPH-ire - developed in the Torres lab and announced in 2015 - pointed the finger straight at the G gamma subunit.

"The program analyzes existing meta-data repositories of protein sequence and PTM activity to reveal "hotspots" of protein alteration. SAPH-ire was designed to accelerate the search for important regulatory targets on protein structures and to provide a better understanding of how proteins communicate with one another inside cells.

***

"Beyond identifying the control mechanism for the pathway, the researchers also learned how it controls the ability of yeast to respond to pheromones in a "switch-like" manner that is either on or off versus an analog manner that is analogous to a volume knob on a stereo.

"While Torres and Choudhury made their discovery in yeast, they believe it will have broad implications because all organisms that have G proteins, including humans, have G gamma tails that are riddled with PTMs. "

Comment: These are biomechanical molecules that control the speed of reactions in an automatic fashion. Note the tail moves. It is the coordinated dance of these molecules working automatically that produces life.

Cell complexity: talking through microtubules

by dhw, Tuesday, May 08, 2018, 11:26 (2179 days ago) @ David Turell

QUOTE: Healthy adult cells don’t usually make TNTs, but stressed or ailing cells appear to induce them by sending out signals to call for help. It’s unclear, though, how healthy cells sense that their neighbors need help or how they physiologically “know” what specific cargo to send.

The evidence for cellular intelligence builds with every article David posts on the subject. Not to be equated with human intelligence of course, but if you saw an animal, bird, insect in trouble and calling for help, and you saw its neighbour providing that help, you wouldn’t hesitate to acknowledge that this was a sign of intelligence. It’s only because these organisms are so tiny and invisible to the naked eye that some folk dismiss the idea.

Under “Stimulus causes protein signalling”:

DAVID’s comment: These are biomechanical molecules that control the speed of reactions in an automatic fashion. Note the tail moves. It is the coordinated dance of these molecules working automatically that produces life.

One should also note that in all forms of life there are automatic activities and non-automatic activities. If we take ourselves as the macrocosm, we depend on a mass of automatic activities that we never even think about until conditions change. Then we use conscious intelligence to make adjustments (though most of the time we have to rely on someone else’s intelligence to do that). I suggest that it is the same in the microcosmic world. Most cellular activity will be automatic. It’s only when things change that intelligence is called on, and the first article tells us that cells can also call on “someone else’s intelligence” to do the job.

Cell complexity: talking through microtubules

by David Turell @, Tuesday, May 08, 2018, 21:57 (2178 days ago) @ dhw

QUOTE: Healthy adult cells don’t usually make TNTs, but stressed or ailing cells appear to induce them by sending out signals to call for help. It’s unclear, though, how healthy cells sense that their neighbors need help or how they physiologically “know” what specific cargo to send.

dhw: The evidence for cellular intelligence builds with every article David posts on the subject. Not to be equated with human intelligence of course, but if you saw an animal, bird, insect in trouble and calling for help, and you saw its neighbour providing that help, you wouldn’t hesitate to acknowledge that this was a sign of intelligence. It’s only because these organisms are so tiny and invisible to the naked eye that some folk dismiss the idea.

Under “Stimulus causes protein signalling”:

DAVID’s comment: These are biomechanical molecules that control the speed of reactions in an automatic fashion. Note the tail moves. It is the coordinated dance of these molecules working automatically that produces life.

dhw: One should also note that in all forms of life there are automatic activities and non-automatic activities. If we take ourselves as the macrocosm, we depend on a mass of automatic activities that we never even think about until conditions change. Then we use conscious intelligence to make adjustments (though most of the time we have to rely on someone else’s intelligence to do that). I suggest that it is the same in the microcosmic world. Most cellular activity will be automatic. It’s only when things change that intelligence is called on, and the first article tells us that cells can also call on “someone else’s intelligence” to do the job.

Obviously intelligence is involved. Cells are so complex they must have a designer. That is where the intelligence comes from.

Cell complexity: talking through microtubules

by dhw, Wednesday, May 09, 2018, 12:47 (2178 days ago) @ David Turell

dhw: The evidence for cellular intelligence builds with every article David posts on the subject. Not to be equated with human intelligence of course, but if you saw an animal, bird, insect in trouble and calling for help, and you saw its neighbour providing that help, you wouldn’t hesitate to acknowledge that this was a sign of intelligence. It’s only because these organisms are so tiny and invisible to the naked eye that some folk dismiss the idea.
dhw: […] Most cellular activity will be automatic. It’s only when things change that intelligence is called on..

DAVID: Obviously intelligence is involved. Cells are so complex they must have a designer. That is where the intelligence comes from.

Two separate issues here: 1) Do cells have their own autonomous intelligence? 2) If they do, where did it come from? Your complexity = design argument is a powerful one. I hope you are now beginning to acknowledge that the case for cellular intelligence is becoming increasingly powerful!

Cell complexity: talking through microtubules

by David Turell @, Wednesday, May 09, 2018, 18:00 (2178 days ago) @ dhw

dhw: The evidence for cellular intelligence builds with every article David posts on the subject. Not to be equated with human intelligence of course, but if you saw an animal, bird, insect in trouble and calling for help, and you saw its neighbour providing that help, you wouldn’t hesitate to acknowledge that this was a sign of intelligence. It’s only because these organisms are so tiny and invisible to the naked eye that some folk dismiss the idea.
dhw: […] Most cellular activity will be automatic. It’s only when things change that intelligence is called on..

DAVID: Obviously intelligence is involved. Cells are so complex they must have a designer. That is where the intelligence comes from.

dhw: Two separate issues here: 1) Do cells have their own autonomous intelligence? 2) If they do, where did it come from? Your complexity = design argument is a powerful one. I hope you are now beginning to acknowledge that the case for cellular intelligence is becoming increasingly powerful!

We agree they certainly act intelligently. That is because of their intelligent design. Your view and my view are possible, but it is obvious the complexity of their responses to stimuli requires a designer.

Cell complexity: talking through microtubules

by dhw, Thursday, May 10, 2018, 14:02 (2177 days ago) @ David Turell

dhw: The evidence for cellular intelligence builds with every article David posts on the subject. Not to be equated with human intelligence of course, but if you saw an animal, bird, insect in trouble and calling for help, and you saw its neighbour providing that help, you wouldn’t hesitate to acknowledge that this was a sign of intelligence. It’s only because these organisms are so tiny and invisible to the naked eye that some folk dismiss the idea.
dhw: […] Most cellular activity will be automatic. It’s only when things change that intelligence is called on..

DAVID: Obviously intelligence is involved. Cells are so complex they must have a designer. That is where the intelligence comes from.

dhw: Two separate issues here: 1) Do cells have their own autonomous intelligence? 2) If they do, where did it come from? Your complexity = design argument is a powerful one. I hope you are now beginning to acknowledge that the case for cellular intelligence is becoming increasingly powerful!

DAVID: We agree they certainly act intelligently. That is because of their intelligent design. Your view and my view are possible, but it is obvious the complexity of their responses to stimuli requires a designer.

This is excellent news. Since you agree that my basic premise of autonomous cellular intelligence is possible, and you have already agreed that you can find no flaw in the logical hypothesis I have built on it, clearly you now agree that your God might possibly have built an autonomous inventive mechanism through which evolution progressed in the higgledy-piggledy manner we can all observe (though we must allow for the occasional dabble).

Cell complexity: talking through microtubules

by David Turell @, Thursday, May 10, 2018, 18:18 (2177 days ago) @ dhw


DAVID: Obviously intelligence is involved. Cells are so complex they must have a designer. That is where the intelligence comes from.

dhw: Two separate issues here: 1) Do cells have their own autonomous intelligence? 2) If they do, where did it come from? Your complexity = design argument is a powerful one. I hope you are now beginning to acknowledge that the case for cellular intelligence is becoming increasingly powerful!

DAVID: We agree they certainly act intelligently. That is because of their intelligent design. Your view and my view are possible, but it is obvious the complexity of their responses to stimuli requires a designer.

dhw: This is excellent news. Since you agree that my basic premise of autonomous cellular intelligence is possible, and you have already agreed that you can find no flaw in the logical hypothesis I have built on it, clearly you now agree that your God might possibly have built an autonomous inventive mechanism through which evolution progressed in the higgledy-piggledy manner we can all observe (though we must allow for the occasional dabble).

Nice attempt at peace. We're back to God's IM which is possible with basic guidelines so that He remains in control of evolution to produce humans.

Cell complexity: talking through microtubules

by dhw, Friday, May 11, 2018, 12:01 (2176 days ago) @ David Turell

DAVID: We agree they certainly act intelligently. That is because of their intelligent design. Your view and my view are possible, but it is obvious the complexity of their responses to stimuli requires a designer.

dhw: This is excellent news. Since you agree that my basic premise of autonomous cellular intelligence is possible, and you have already agreed that you can find no flaw in the logical hypothesis I have built on it, clearly you now agree that your God might possibly have built an autonomous inventive mechanism through which evolution progressed in the higgledy-piggledy manner we can all observe (though we must allow for the occasional dabble).

DAVID: Nice attempt at peace. We're back to God's IM which is possible with basic guidelines so that He remains in control of evolution to produce humans.

You wrote that your view and my view were possible. As you very well know, your view is an IM “with basic guidelines” and my view is an autonomous IM, based on cellular intelligence. You have said that my view is possible, or is this yet another case of x on a Wednesday and y on a Thursday? The theistic version of my hypothesis allows for dabbling, which could apply to humans. My major objections to your hypothesis are firstly your insistence that every single innovation, lifestyle and natural wonder had to be individually dabbled or preprogrammed by your God, and secondly that all of them were somehow geared to the production of the sapiens brain.

Cell complexity: talking through microtubules

by David Turell @, Friday, May 11, 2018, 15:04 (2176 days ago) @ dhw

DAVID: We agree they certainly act intelligently. That is because of their intelligent design. Your view and my view are possible, but it is obvious the complexity of their responses to stimuli requires a designer.

dhw: This is excellent news. Since you agree that my basic premise of autonomous cellular intelligence is possible, and you have already agreed that you can find no flaw in the logical hypothesis I have built on it, clearly you now agree that your God might possibly have built an autonomous inventive mechanism through which evolution progressed in the higgledy-piggledy manner we can all observe (though we must allow for the occasional dabble).

DAVID: Nice attempt at peace. We're back to God's IM which is possible with basic guidelines so that He remains in control of evolution to produce humans.

dhw: You wrote that your view and my view were possible. As you very well know, your view is an IM “with basic guidelines” and my view is an autonomous IM, based on cellular intelligence. You have said that my view is possible, or is this yet another case of x on a Wednesday and y on a Thursday? The theistic version of my hypothesis allows for dabbling, which could apply to humans. My major objections to your hypothesis are firstly your insistence that every single innovation, lifestyle and natural wonder had to be individually dabbled or preprogrammed by your God, and secondly that all of them were somehow geared to the production of the sapiens brain.

I'll stick to humans as the supreme goal of God's evolution.

Cell complexity: how mitochondria maintain DNA

by David Turell @, Friday, May 11, 2018, 18:19 (2176 days ago) @ David Turell

The DNA in mitochondria differs from that in the nucleus. It has a circular form:

https://phys.org/news/2018-05-mitochondria-art-dna-maintenance.html

"However, biologists also know that most of our cells have mitochondria that do, in fact, retain the circular DNA, the chromosome 'M,' which they inherited from their prokaryotic ancestors.

"One might then ask: Do mitochondria contain linear DNA? The correct answer to this second, and somewhat sneaky question is, again, affirmative. Nucleoids in mitochondria do need to be circular in order for the machinery that copies their DNA to work. Transcription in mitochondria is directly coupled to replication, and also requires circularized nucleoids. However, linear nucleoids exist in a healthy state of equilibrium with circular nucleoids within the mitochondria network. This provides a way for the cell or tissue to control the abundance of mtDNA directly, and by implication, the state and abundance of mitochondria.

"What is the fate of linear mtDNA? Double-strand breaks (DSBs) are continually generated as a byproduct of replication stalling, or from failed DNA repair of damaged and incorrectly replicated nucleotides. Although nucleoids can normally replicate themselves in about 90 minutes, DNA polymerases are hung out to dry when nucleotide stores are insufficient or become improperly balanced. When that happens, things break down; essential factors begin to leave the replication-transcription complex, and proper proofreading becomes a frequent casualty.

***

"Until recently, it was not understood how linear mtDNA was degraded. Authors of a new paper in Nature have now shown that the same exact machinery responsible for replicating mtDNA also polices it for breaks. The three main proteins involved, the helicase TWNK, the polymerase POLG, and the exonuclease MGME1, were found to bind together into a functional unit. TWNK first acts to unwind the DNA so that the individual strands can be accessed. MGME1, which has a strong bias for operation in the 5' to 3' direction of single-stranded DNA then begins to digest one strand.

***

"Some additional insights (and warnings) into how double-strand breaks might occur and resolve have been provided by researchers Doug Turnbill and Robert Taylor from the Wellcome Center for Mitochondrial Research. In one particular paper, they proposed that mtDNA deletions are most commonly generated during repair of DNA damage as opposed to replication errors. More specifically, they offer that characteristic deletions are initiated by single-stranded segments of mtDNA that were, in turn, generated by exonucleases attacking double-strand breaks. The free single strands would be able to anneal with microhomology or repeat sequences on other single-stranded mtDNA, and undergo repair to an intact but partially deleted state."

Comment: Obviously the cell and its mitochonria must have exacting repair mechanisms, and these must have been present from the beginning of life and carried into multcellularity. Only design explains this.

Cell complexity: an enzymes multiple functions

by David Turell @, Saturday, May 19, 2018, 02:17 (2168 days ago) @ David Turell

Another complex enzyme has had its functions discovered:

https://www.sciencedaily.com/releases/2018/05/180517163337.htm

"A team of Texas A&M and Texas A&M AgriLife Research scientists now have a deeper understanding of a large switch/sucrose non-fermentable (SWI/SNF) protein complex that plays a pivotal role in plant and human gene expression that causes life-threatening diseases such as cancer.

***

"The team has been working for years on how microRNAs are produced in the model plant Arabidopsis. MicroRNAs are tiny regulatory RNA molecules widely present in multicellular organisms. In humans, microRNAs inhibit more than 60 percent of human genes and are actively exploited as potent drugs to cure human diseases, according to the scientists.

"In plants, the molecules can also control many aspects of life such as plant architecture, and responses to hostile environmental conditions. MicroRNAs are also widely engineered in agricultural crops and animals for better yield and quality.

"MicroRNAs are produced in a factory inside cells from long substrates that can be hundreds or thousands of bases and also contain a distinct hairpin-structure. The factory contains a scissor-like enzyme called Dicer, and some assistants that help to fetch the long substrates. One of the assistants is known as Serrate protein, Zhang said.

"'Also, the shape of the substrates is very critical for microRNA production," Zhang said. "If the shapes are changed, then the substrates do not fit the Dicer scissor and can not be cut, and microRNAs are not made."

***

"'Also, the shape of the substrates is very critical for microRNA production," Zhang said. "If the shapes are changed, then the substrates do not fit the Dicer scissor and can not be cut, and microRNAs are not made."

***

"Wang said CHR2 is essential for producing RNA from DNA templates because its ATPase activity breaks down ATP to generate energy.

***

"'That meant, CHR2, when brought into the factory by Serrate, changes the settings inside the factory through its motor activity."

***

"'The results are significant because they provide an additional unknown layer of microRNA level regulation. For the first time an explanation is provided for many earlier reports showing that the level of microRNA substrates in many cases does not reflect the amount of mature microRNA," according to one reviewer for the paper.

"'The study is novel and exciting. It shows that the secondary structure of microRNA substrates contains a new informational code that needs to be interpreted by CHR2 and Serrate proteins (before operation of the factory)," according to the other reviewers for the paper. (my bold)

***

"The groundbreaking work from Zhang's lab reveals the two separate functions for CHR2 in production of microRNAs.

"'The work identifies a unique gene-editing target to control microRNA amount for systematically improving agricultural traits such as plant architecture, yield, quality and response to hostile environments," Zhang said."

Comment: Note my bold. Life runs on information. Enzymes and other proteins carry information to the cells to instruct changes in production. The degree of complexity cannot be developed by chance mutation.

Cell complexity: an enzymes multiple functions

by dhw, Saturday, May 19, 2018, 09:56 (2168 days ago) @ David Turell

DAVID’s comment: Note my bold. Life runs on information. Enzymes and other proteins carry information to the cells to instruct changes in production. The degree of complexity cannot be developed by chance mutation.


Life runs on the ability of organisms to absorb, pass on, process and use information, and I suspect many of us would regard that ability as a sign of intelligence. I agree with you that belief in chance mutation as the developer of such complexity requires a great deal of faith!

Cell complexity: ATPase multiple functions

by David Turell @, Thursday, August 22, 2019, 06:13 (1708 days ago) @ David Turell

Energy machines in cells, driving flagella, etc.:

https://evolutionnews.org/2019/08/design-for-atp-extends-beyond-the-rotary-engine/

"A paper in PNAS by Kwangho Nam and Martin Karplus explores “Insights into the origin of the high energy-conversion efficiency of F1-ATPase.” And do they mean efficiency!

"F1-ATPase is a small motor protein, composed of 3 α- and 3 β-subunits that surround a central γ-subunit. The β-subunits alternate cyclically between 2 major conformational states to produce the rotation of the γ-subunit. Although the rotation on the microsecond timescale is powered by the differential binding of ATP and its hydrolysis products ADP and HPO42−, there is near-100% conversion efficiency of the free energy of ATP hydrolysis, which occurs on the picosecond timescale. The free-energy profile constructed for the 360° rotation cycle shows that F1-ATPase achieves its high energy-conversion efficiency by elegantly separating fast catalytic events, which involve small local conformational changes, from the slow binding/release of ligands involved in the large conformational change.

***

"How can ATP synthase achieve near-100% efficiency, such that the energy from one process is completely converted to another, with almost zero loss? Thermal escape is too rapid to overcome, even at this scale.

"The authors found an “elegant separation” between two catalytic events that operate at timescales differing by six orders of magnitude. This apparently gives the motor time for conformational changes in the protein parts and release of products that drive rotation of the rotor. The elasticity or “stiffness” in the rotor also contributes to efficient energy conversion. So finely tuned is each part of the engine to the others, the free energy “changes linearly along the rotation coordinate.” This means that the motor “functions near the maximum possible efficiency.”

***

"A description in BioArchitecture states, “Bacterial enzymes have been clocked to run at up to 42,000 rpm under low load, though for intact enzymes under physiological conditions the number is closer to 6000 rpm.” A typical car starts redlining at that value. High-performance racing cars peak a little above 10,000 rpm. Isn’t it amazing what chance can do?

"Molecular machines, like the rotary ATPases described here, seem to have much in common with man-made machines. However, the analogies hold only to a certain point and are in large parts not fully understood. What is evident is that several billion years of evolution have resulted in biological motors that are unsurpassed in efficiency, fine-tuning to their environment and sustainability.

***

"The first paper was concerned primarily with the F1 part of ATP synthase, where ATP synthesis or hydrolysis occurs. The F0 part, where protons drive rotation of a carousel-like wheel, also contributes to the efficiency. It drives the γ-subunit that acts like a camshaft. The camshaft extends into the F1 part, in effect “snapping” ADP and phosphate together to form ATP in three stages per revolution: synthesis, ejection, and loading.

***

"They solved high-resolution cryo–electron microscopy structures of the ATP synthase complex, extracting 13 rotational substates. This collection of structures revealed that the rotation of the Fo ring and central stalk is coupled with partial rotations of the F1 head. This flexibility may enable the head to better couple continuous rotation with discrete ATP synthesis events.

"An animation in the paper shows the F1 domain undergoing a rocking motion back and forth as the F0 domain rotates around continuously. The rocking motion is achieved by means of another finely tuned protein called OSCP. The beauty of this solution allows for F1 heads to accommodate differing sizes of F0 rotors through a universal joint.

***

" Some animations of ATP synthesis show the products ejecting from the machine, as if they just fly off into the air. Actually, transport of ADP into and ATP out of the motor are also tightly regulated. The “mitochondrial ADP/ATP carrier” (AAC) is right there, like a UPS truck, to get the products where they are needed.

Inside the mitochondrion, as reported here before, there are inner and outer membranes, with TIM and TOM transporters that control what enters and exits.

***

"Translating this into a more everyday analogy, the AAC truck driver keeps an eye on how many protons are leaking out into the cytoplasm, and calls back to the engine house to have them slow down production. When the truck driver can keep up with production, proton leakage is small (negative regulation). But when more protons leak out, the driver warns that ATP synthase is outpacing demand.

***

"As more details of ATP synthase come to light, more and more fine-tuning appears. The synthesis of ATP, necessary from the very start of metabolic life, is now seen to be phenomenally efficient and masterfully regulated by multiple parts working together. Just give chance billions of years, and miracles like this can happen. Not."

Comment: Better machines than humans can create.

Cell complexity: mechanism of mitochondrial repair

by David Turell @, Friday, April 03, 2020, 00:40 (1483 days ago) @ David Turell

Found but not fully understood:

https://phys.org/news/2020-04-renew-powerhouses-cells-workshop-mode.html

"If the energy supply of a cell is disturbed by damage, it can protect itself from functional losses and repair itself in a kind of workshop mode.

***

"The tasks of mitochondria include very basic processes such as the constant energy supply of the cell. The power machinery in mitochondria consists of five components, the so-called complexes I-V. In them, the food we eat is ultimately converted into energy for the cell. If the cellular energy supply is no longer guaranteed due to disturbances in signalling processes, this has serious consequences for the entire organism,

***

"'In our most recent work, we have discovered a rescue route that enables cells to repair damage of a particularly sensitive part of complex I," said Trifunovic. "Repairing something is a far more energy-efficient self-help mechanism compared to the effort that would be required to completely destroy and rebuild this entire complex." (my bold)

"The specific rescue route Trifunovic identified also acts as a safety valve for the cell. If the rescue route becomes active, the dysfunctional component quickly switches to a shutdown mode and 'goes to the workshop.' This way, the cells prevent harmful reactive oxygen species from being produced and released in the powerhouse engine. Trifunovic remarked: "So far, very little is known about how this machinery is maintained and regulated. Our results shed light on this process and allow us to explore further therapeutic possibilities."

"In addition to the general novelty of the entire mechanism, she was particularly surprised to see that it is often better for the organism to keep some powerhouse machine components running despite damage, and not to put all damaged components into 'workshop mode' at the same time or to dismantle them completely. It is possible that functions of individual components, which go beyond energy supply, also play a role."

Comment: Note my bold. Quick repair by a backup system is obviously needed and reeks of planned design, never a chance natural event.

Cell complexity: molecular binding controls

by David Turell @, Tuesday, January 25, 2022, 20:28 (820 days ago) @ David Turell

Among the myriad of molecules in a cell, how do they know how tov whom they should bind:

https://phys.org/news/2022-01-probing-proteins-pair-cells.html

"Despite its minute size, a single cell contains billions of molecules that bustle around and bind to one another, carrying out vital functions. The human genome encodes about 20,000 proteins, most of which interact with partner proteins to mediate upwards of 400,000 distinct interactions. These partners don't just latch onto one another haphazardly; they only bind to very specific companions that they must recognize inside the crowded cell.

***

"The average human protein is composed of approximately 400 building blocks called amino acids, which are strung together and folded into a complex 3D structure. Within this long string of building blocks, some proteins contain stretches of 4-6 amino acids called short linear motifs (SLiMs), which mediate protein-protein interactions. Despite their simplicity and small size, SLiMs and their binding partners facilitate key cellular processes. However, it's been historically difficult to devise experiments to probe how SLiMs recognize their specific binding partners.

***

"Using the detailed information they gleaned from studying these interactions, the researchers created their own synthetic molecule capable of binding extremely tightly to a protein called ENAH, which is implicated in cancer metastasis. The team shared their findings in a pair of eLife studies, one published on January 25, 2022 and the other on December 2, 2021.

***

"To survey SLiMs with a wide range of binding affinities, Keating, Hwang, and their colleagues developed their own screen called MassTitr.

"The researchers also suspected that the amino acids on either side of the SLiM's core 4-6 amino acid sequence might play an underappreciated role in binding. To test their theory, they used MassTitr to screen the human proteome in longer chunks comprised of 36 amino acids, in order to see which "extended" SLiMs would associate with the protein ENAH.

"ENAH, sometimes referred to as Mena, helps cells to move. This ability to migrate is critical for healthy cells, but cancer cells can coopt it to spread. Scientists have found that reducing the amount of ENAH decreases the cancer cells's ability to invade other tissues—suggesting that formulating drugs to disrupt this protein and its interactions could treat cancer.

"Thanks to MassTitr, the team identified 33 SLiM-containing proteins that bound to ENAH—19 of which are potentially novel binding partners. They also discovered three distinct patterns of amino acids flanking core SLiM sequences that helped the SLiMs bind even tighter to ENAH. Of these extended SLiMs, one found in a protein called PCARE bound to ENAH with the highest known affinity of any SLiM to date.

***

"Hwang's biggest takeaway from the project is that things are not always as they seem: even short, simple protein segments can play complex roles in the cell. As she puts it: "We should really appreciate SLiMs more."

Comment: this study shows how molecules know with whom to combine or react, automatically, no thought involved because of the design. Cell intelligence is in the design, not autonomously
active.

Cell complexity: producing while under constant repair

by David Turell @, Saturday, December 24, 2022, 15:34 (488 days ago) @ David Turell

Repair of microtubules:

https://www.cell.com/current-biology/fulltext/S0960-9822(22)01851-6?dgcid=raven_jbs_aip...

"Microtubule self-repair has been studied both in vitro and in vivo as an underlying mechanism of microtubule stability. The turnover of tubulin dimers along the microtubule has challenged the pre-existing dogma that only growing ends are dynamic. However, although there is clear evidence of tubulin incorporation into the shaft of polymerized microtubules in vitro, the possibility of such events occurring in living cells remains uncertain. In this study, we investigated this possibility by microinjecting purified tubulin dimers labeled with a red fluorophore into the cytoplasm of cells expressing GFP-tubulin. We observed the appearance of red dots along the pre-existing green microtubule within minutes. We found that the fluorescence intensities of these red dots were inversely correlated with the green signal, suggesting that the red dimers were incorporated into the microtubules and replaced the pre-existing green dimers. Lateral distance from the microtubule center was similar to that in incorporation sites and in growing ends. The saturation of the size and spatial frequency of incorporations as a function of injected tubulin concentration and post-injection delay suggested that the injected dimers incorporated into a finite number of damaged sites. By our low estimate, within a few minutes of the injections, free dimers incorporated into major repair sites every 70 μm of microtubules. Finally, we mapped the location of these sites in micropatterned cells and found that they were more concentrated in regions where the actin filament network was less dense and where microtubules exhibited greater lateral fluctuations."

Comment: this abstract of the study is quite clear. Microtubules are vital conduits for transfer of molecules in the active cell in constant production. Only design can produce this degree of complexity. We now study at a level of function at which Darwin just-so stories won't work.

Cell complexity: formation of the centriole

by David Turell @, Thursday, April 11, 2024, 14:55 (14 days ago) @ David Turell

A fully pictorial reproduction with discussion:

https://www.cell.com/cell/fulltext/S0092-8674(24)00316-7?dgcid=raven_jbs_aip_email

Centriole biogenesis, as in most organelle assemblies, involves the sequential recruitment of sub-structural elements that will support its function. To uncover this process, we correlated the spatial location of 24 centriolar proteins with structural features using expansion microscopy. A time-series reconstruction of protein distributions throughout human procentriole assembly unveiled the molecular architecture of the centriole biogenesis steps. We found that the process initiates with the formation of a naked cartwheel devoid of microtubules. Next, the bloom phase progresses with microtubule blade assembly, concomitantly with radial separation and rapid cartwheel growth. In the subsequent elongation phase, the tubulin backbone grows linearly with the recruitment of the A-C linker, followed by proteins of the inner scaffold (IS). By following six structural modules, we modeled 4D assembly of the human centriole. Collectively, this work provides a framework to investigate the spatial and temporal assembly of large macromolecules.

Comment: I cannot reproduce any portion of this study which is filled with picture illustrations of all the steps and parts. If possible open the website and skim through. The complexity of the design will be startling.

Cell complexity:mitochondrial protein supply controls

by David Turell @, Monday, April 16, 2018, 20:47 (2200 days ago) @ David Turell

Mitochondria require a constant supply of proteins from the cell, and this must be controlled for proper energy production:

https://phys.org/news/2018-04-scientists-pathway-protein-import-mitochondria.html

"mitochondria rely on a stream of proteins to sustain this energy production. Nearly all their proteins are manufactured in the surrounding gel-like cytoplasm, and must be imported into the mitochondria to keep the powerhouse running.

***

"This newly-discovered molecular pathway, called mitoCPR, detects import mishaps and preserves mitochondrial function in the midst of such stress.

"'This is the first mechanism identified that surveils mitochondrial protein import, and helps mitochondria when they can't get the proteins they need," says Angelika Amon,...."Responses to mitochondrial stress have been established before, but this one specifically targets the surface of the mitochondria, clearing out the misfolded proteins that are stuck in the pores."

***

"The protein products from these genes are ultimately made in the cytoplasm outside the nucleus, and then guided to the mitochondria. These "precursor" proteins contain a special molecular zip code that guides them through the channels at the surface of the mitochondria to their respective homes.

"The proteins must be unfolded and delicately threaded through the narrow channels in order to enter the mitochondria. This creates a precarious situation; if the demand is too high, or the proteins are folded when they shouldn't be, a bottleneck forms that none shall pass.

***

"'The machinery that we've identified seems to evict proteins that are sitting on the surface of the mitochondria and sends them for degradation," Amon says. "Another possibility is that this mitoCPR pathway might actually unfold these proteins, and in doing so give them a second chance to be pushed through the membrane."

"Two other pathways were recently identified in yeast that also respond to accumulated mitochondrial proteins. However, both simply clear protein refuse from the cytoplasm around the mitochondria, rather than removing the proteins collecting on the mitochondria themselves.

***

"'Twenty years ago, scientists recognized mitoCPR as some kind of mechanism against mitochondrial dysfunction," Weidberg says. "Today we've finally characterized it, given it a name, and identified its precise function: to help mitochondrial protein import."
As the import process slows, Amon and Weidberg determined that the protein that initiates mitoCPR—the transcription factor Pdr3—binds to DNA within the nucleus, inducing the expression of a gene known as CIS1. The resultant Cis1 protein binds to the channel at the surface of the mitochondrion, and recruits yet another protein, the AAA+ adenosine triphosphatase Msp1, to help clear unimported proteins from the mitochondrial surface and mediate their degradation. Although the MDR response pathway differs from that of mitoCPR, both rely on Pdr3 activation. In fact, mitoCPR requires it.

"'Whether the two pathways interact with one another is a very interesting question," Amon says. "The mitochondria make a lot of biosynthetic molecules, and blocking that function by messing with protein import could lead to the accumulation of intermediate metabolites. These can be toxic to the cell, so you could imagine that activating the MDR response might pump out harmful intermediates."

"The question of what activates Pdr3 to initiate mitoCPR is still unclear, but Weidberg has some ideas related to signals stemming from the build-up of toxic metabolite intermediates. It's also yet to be determined whether an analogous pathway exists in more complex organisms, although there is some evidence that the mitochondria do communicate with the nucleus in other eukaryotes besides yeast. "

Comment: What is interesting here is that mitochondria are thought to be engulfed bacteria who then formed the energy mechanism. This protective process had to be immediately developed or the entire mitochondrial mechanism would not have lasted. Design, not chance! And note all of these complex mechanisms act automatically, no thought involved.

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