Predatory bacteria (Introduction)

by David Turell @, Monday, February 22, 2016, 15:46 (3196 days ago)

One example is shown in this study of how E. coli protects itself. It may be possible to genetically modify predators to attack pathogens now resistant to antibiotics:-https://www.sciencedaily.com/releases/2016/02/160221142245.htm-"Meet Bdellovibrio bacteriovorus, a bacterial predator that is an efficient killer of Gram-negative bacteria, such as the prevalent E. coli bacterium. It is present in soil and, just like E. coli, it can also be found in the human gut, where a complex ecosystem of bacterial inhabitants exists.-"This ferocious bacterial predator enters its prey and devours it from the inside while dividing into four or six progenies. It then bursts open its prey and starts its hunt for the next. B. bacteriovorus is a formidable opponent: It is not only an efficient killer, but it is also extremely fast. Although the bacterium itself is hardly one micrometer long, it can reach speeds of 160 micrometers per second, making it the "world champion" in speed swimming and ten times faster than the E. coli.-"'Knowledge of defense and attack mechanisms in bacteria is crucial for future development of potential alternatives to antibiotics," explains Dr. Daniel Koster, from the department of Ecology, Evolution and Behavior at the Hebrew University in Jerusalem.-"B. bacteriovorus kills bacteria by a whole different mechanism of action than classical antibiotics, and as such, predatory bacteria might in the future constitute a viable alternative to these antibiotics," Koster says.-***-"Koster explained how E. coli was able to survive in the fragmented environment: "It seems that groups of E. coli 'hide' in the many corners of the fragmented environment, where they readily stick as bio-films that probably protect them against B. bacteriovorus. Our findings provide important information because in natural environments, such as our gut, the bacterium also lives in fragmented spaces."-"It is not yet known precisely how E. coli is able to defend itself against predatory bacteria, but the research contributes to the understanding of the behavior of the predatory bacteria, which could become a possible alternative to antibiotics in the future."-Comment: E. coli don't 'plan' to hide. They simply multiply everywhere and end up in 'hiding places'. Also they divide every 20 minutes which means they reproduce exponentially. If predator bacteria are modified for medical purposes they will have to used in enormous numbers and divide more quickly to kill all the bad bugs.

Clever bacteria: E. coli drug protection system

by David Turell @, Monday, February 22, 2016, 18:05 (3196 days ago) @ David Turell

E. Coli, like all gram negative bacteria have protective biochemical complexes in their walls to stop harmful drugs or other chemicals to enter:-http://phys.org/news/2016-02-scientists-pave-superbug-drugs.html-"Gram-negative bacteria is particularly resistant to antibiotics because of its cells' impermeable lipid-based outer membrane. (my bold)-"This outer membrane acts as a defensive barrier against attacks from the human immune system and antibiotic drugs. It allows the pathogenic bacteria to survive, but removing this barrier causes the bacteria to become more vulnerable and die.-***-"'All Gram-negative bacteria have a defensive cell wall. Beta-barrel proteins form the gates of the cell wall for importing nutrition and secreting important biological molecules.-"The beta-barrel assembly machinery (BAM) is responsible for building the gates (beta-barrel proteins) in the cell wall.-"'Stopping the beta-barrel assembly machine from building the gates in the cell wall cause the bacteria to die."
Scientists studied the gram-negative bacteria E.coli, in which the beta-barrel assembly machinery contains five subunits - known as BamA, BamB, BamC, BamD and BamE. They wanted to know exactly how these subunits work together to insert the outer membrane proteins into the outer membrane or cell wall.-"Prof Dong said: "Our research shows the whole beta-barrel assembly machinery structures in two states - the starting and finishing states. We found that the five subunits form a ring structure and work together to perform outer membrane protein insertion using a novel rotation and insertion mechanism.-"'Our work is the first to show the entire BAM complex. It paves the way for developing new-generation drugs.-"'The beta-barrel assembly machinery is absolutely essential for Gram-negative bacteria to survive. The subunit BamA is located in the outer membrane and exposed to the outer side of the bacteria, which provides a great target for new drugs.-"'In Human mitochondria, a similar complex called sorting and assembly machinery complex (SAM) is responsible for building the outer membrane proteins in the outer membrane of mitochondria."-Comment: Again these are automatic protein complex defense mechanisms, not cell thinking. All membranes have a lipid layer. The real issue is the BAM complex. Most E. coli are not dangerous to us.

Predatory bacteria: whole new hosts found

by David Turell @, Wednesday, September 07, 2022, 01:09 (807 days ago) @ David Turell

Review article of new findings:

https://www.scientificamerican.com/article/predatory-bacteria-are-fierce-ballistic-and-...


"Bdellovibrio microbes are bacteria-seeking torpedoes sometimes called “the world’s smallest hunters.” Only one fifth the size of a typical bacterium, they punch above their weight. An individual Bdellovibrio darts about until it happens to smash into prey. When it does, the impact is so violent that the victim reels several cell lengths and stops moving within seconds.

"Affixed to its victim ballistically, Bdellovibrio bores inside and cleans out the place like a cross-country team at a post-10K buffet. Its systems for relieving prey of their innards are so evolved (one author termed the process “exquisite molecular dissection”) that when it is finished eating, nothing is left but ghosts and membrane fragments.

"Most bacteria eat detritus or produce their own food. But since Stolp’s discovery of the hunter Bdellovibrio, scientists have come to realize predatory bacteria are diverse, important and potentially useful. They rival killers such as amoebas and viruses as cullers of the vast bacterial herds of the soil, and scientists hope that they could also be put to work in humans and animals as dynamic antibiotics.

***
"Most bacterial predators don’t invade their prey like Bdellovibrio does, but their strategies can be no less inventive. Lysobacter specializes in demolition on contact and can blow up not only other bacteria but also green algae, fungi and even little squirming animals called roundworms.

"Vampirovibrio and Vampirococcus, true to their name, have cytoskeletal protrusions sometimes termed “fangs” that the sink into the bodies of prey before draining the contents. Some of these vampires are actually vegetarian: Vampirovibrio chlorellavorus hunts green algae. It’s so good at its job that it has become a pest in experimental algal bioreactors designed to produce biofuel. Once it finds its way into one of the reactors, almost 100 percent of the crop is dead within a day or two.

"Others hunt in “wolf packs.” Herpetosiphon bacteria are huge gliding filaments that can exceed a millimeter in length and are apparently lapsed algae. Under the microscope, they look like a swarm of snakes and use their collective muscle to punch holes in colonies of their prey like a battering ram or bulldozer. Once inside, they torch the village by bursting prey with disruptive chemicals while other Herpetosiphon cells form a wall to prevent escapes. They all then feast on the entrails.

***

"To begin to grasp the true ecological power of predatory bacteria, a study published in mBio in April 2021 measured predators’ response to radioactively-labeled food added directly to their habitat in 15 wild sites across North America. It found that dedicated (“obligate”) predators such as Bdellovibrio and Vampirovibrio grew, metabolized and fed much faster than nonpredatory bacteria when food was abundant. And the more food there was, the more dominant they became in the ecosystem, a finding that also holds true for predatory animals.

"But bacterial predators’ significance reaches beyond ecology. The biochemical arsenals of these microbes are rich targets for biotechnology: new antibiotics are sorely needed. Scientists have already proposed and tested the idea of using whole predatory bacteria in animals—applied topically, ingested or even injected—as living antibiotics. Remarkably, they so far seem to be both safe and effective in lab animals. Resistance may prove more elusive for pathogens against wily, evolvable predators than against the static biochemical antibiotics we currently employ."

Comment: in God's eat or be eaten world these bacteria can be used just as we are now, and still, using fungus attack/defense products as antibiotics. The theodicy cranks will complain God should have made the world peaceful, but He chose not to for his own reasons. We have to work with it as it is, with our God-given brains.

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