A series of 10-20 G-proteins is set off:

https://medicalxpress.com/news/2019-05-common-view-retinal-cells-mammals.html

Johns Hopkins vision scientists say that their experiments, described March 12 in Proceedings of the National Academy of Sciences, show that the number of G protein molecules activated in the cascade of reactions is far fewer—involving only 10-20 of them in the rods of mice.

The new finding matters, say the scientists, because G proteins belong to a very large family of biochemical signaling pathways called G protein-coupled-receptors, which are among the most abundant signaling pathways in biology, says King-Wai Yau, Ph.D., professor of neuroscience and ophthalmology at the Johns Hopkins University School of Medicine.

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When a photon of light hits a rod in the retina, it is absorbed by a light-sensing protein, called rhodopsin, which is embedded in membranes within the cell. Rhodopsin then activates G proteins, which, in turn, activate other enzymes. It is the number of G protein molecules activated by one rhodopsin molecule that the new experiments challenge, Yau says. He notes that other scientists had speculated that the number of activated G protein molecules may be much less than the many hundred originally proposed, but the number was difficult to directly measure in intact rods.

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By using mathematical tools to analyze the electrical signal, Yue and Silverman found that the electrical signal triggered by a single G protein molecule was only one-twelfth to one-fourteenth the size of estimates of signals coming from a single rhodopsin molecule. Thus, they estimated that one rhodopsin activates approximately 10-20 G protein molecules.

Yau had previously found that, in a similar signaling cascade that facilitates the sense of smell in mice, one activated receptor molecule has a very low probability of activating one G protein molecule. By comparison, the finding that such signaling systems in vision trigger 10-20 molecules may reflect the visual system's unique need to detect light in very dim light conditions, without having to group together information from multiple rods, which would sacrifice spatial resolution.

Comment: More obvious evidence for the need for design. This process needs to be set up all at once, to function properly.

A study in squirrels:

https://www.quantamagazine.org/mitochondria-double-as-tiny-lenses-in-the-eye-20220405/

"A study published last month in Science Advances found that inside mammalian eyes, mitochondria, the organelles that power cells, may serve a second role as microscopic lenses, helping to focus light on the photoreceptor pigments that convert the light into neural signals for the brain to interpret.

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"The lens at the very front of the eye focuses light from the environment onto a thin layer of tissue called the retina in the back. There, photoreceptor cells — cones that paint our world in color and rods that help us navigate in low light — absorb the light and translate it into nerve signals that propagate into the brain. But light-sensitive pigments sit at the very ends of photoreceptors, right behind a thick bundle of mitochondria. The odd placement of this bundle turns the mitochondria into seemingly unnecessary, light-scattering obstacles.

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"Instead of being obstacles, the mitochondrial bundles seem to play a critical role in helping to funnel as much light as possible to the photoreceptors with minimal loss, Li said.

"With simulations, he and his colleagues confirmed that the lens effect was caused primarily by the mitochondrial bundle itself, not the membrane surrounding it (though the membrane played a role).

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"Li and his colleagues think that what they saw in ground squirrels is also likely to occur in humans and other primates, who have very similar cone structures. They suggested that it could even explain a phenomenon, first reported in 1933 and called the Stiles-Crawford effect, in which light passing through the very center of the pupil is perceived as brighter than light entering at an angle. Because that central light may be more aligned with the mitochondrial bundles, the researchers think that it may get focused better onto a cone’s pigments. They suggest that measuring the Stiles-Crawford effect might help with the early detection of retinal diseases, since many of them cause damage and changes to mitochondria. Li’s team hopes to analyze how diseased mitochondria may focus light differently.

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"At least in cones, these mitochondria may have evolved to serve as microlenses because their membranes are made up of lipids, which have a natural ability to bend light, Li said. “They’re just the best material to achieve this function.'”

Comment: so our crazy backward retina is found to be marvelously designed for sharp vision. The complaints about God doing it improperly can be cast aside.

We don't and must use instruments:

https://www.sciencedaily.com/releases/2022/01/220119142819.htm

"Camels have a renowned ability to survive on little water. They are also adept at finding something to drink in the vast desert, using noses that are exquisite moisture detectors. In a new study in ACS Nano, researchers describe a humidity sensor inspired by the structure and properties of camels' noses. In experiments, they found this device could reliably detect variations in humidity in settings that included industrial exhaust and the air surrounding human skin.

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"Narrow, scroll-like passages within a camel's nose create a large surface area, which is lined with water-absorbing mucus. To mimic the high-surface-area structure within the nose, the team created a porous polymer network. On it, they placed moisture-attracting molecules called zwitterions to simulate the property of mucus to change capacitance as humidity varies. In experiments, the device was durable and could monitor fluctuations in humidity in hot industrial exhaust, find the location of a water source and sense moisture emanating from the human body. Not only did the sensor respond to changes in a person's skin perspiration as they exercised, it detected the presence of a human finger and could even follow its path in a V or L shape. This sensitivity suggests that the device could become the basis for a touchless interface through which someone could communicate with a computer, according to the researchers. What's more, the sensor's electrical response to moisture can be tuned or adjusted, much like the signals sent out by human neurons -- potentially allowing it to learn via artificial intelligence, they say."

Comment: Great design, as usual better than the ones we make. Did this come with the original camelids? One can propose starting close to a desert and by slowly venturing out the design develops. But the complexity is precise and effective and I believe far beyond dhw's wishes for cellular intelligence. Cells just ain't that smart, even if given design ability by God as dhw always theorizes. A purposeful God sees established endpoints to development by evolution. Cell designers don't have God's foresight or His direct abilities. That makes dhw's designer cells as secondhand designers n ot llikely to give God the results He definitely wants.

Dandelion seed dispersal:

https://www.sciencedaily.com/releases/2022/06/220601111753.htm

"Known for their fluffiness and uncanny ability to help children tell the time, dandelions provide essential early-Spring food for pollinators like bees, birds, butterflies, and moths.

"Their seeds are some of the best flyers in nature, catching the wind and spreading as far as 100 kilometres. Part of how they do this is by tuning their flight depending on the weather. (my bold)

"Each dandelion seed is tethered by a thin tube to around 100 bristles, which form the parachute-like structure. When seeds break free from the flower head, these bundles of hairs catch the wind and carry their seeds. This hairy parachute closes when the air is humid, which often means the wind is weak. In drier, more windy conditions, dandelions widen their parachutes to better catch the wind so the seeds can fly freely.

"Their work, published in Nature Communications, found the seed-carrying parachutes open and close using something like actuators -- devices that convert signals into movement -- without using energy.

"The centre of the parachutes senses the humidity of their immediate environment by absorbing water molecules from the air. Responding to these humidity signals, they 'decide' to either open their parachutes and fly away, or to close their parachutes and stay put.

"They also found that the actuator has a unique radial, tube-like design to which the parachute hairs are attached to ensure simultaneous movement. The actuator changes its shape to either open or close their parachutes.

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"They found that parachute opening is modulated by the level of humidity in the atmosphere: higher humidity triggered swelling in the actuator and mechanical movement of hairs upwards, which closed the parachutes. Some regions of the actuator swelled noticeably, whereas others, such as the vasculature, barely changed. They observed that the actuator shape change was caused by uptake and release of water droplets, creating a crease in the area the parachute hairs are attached.

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"Plant structures can serve as important inspiration for soft robotics as, like plants, these robots don't use joints or rigid parts to move appendages. Finding out how dandelion parachutes respond to their environment by moving many appendages simultaneously could help engineers create robots that move multiple fingers and arms with very simple yet functional designs. The way the dandelion actuator changes shape in some regions but not others can also teach us about mechanisms of shaping and movement in soft robots and biological tissues."

Comment: this seems to be a physical reaction to water vapor, but it is possible some biochemical reactions may be helping yet to be discovered. Teh plant doesn't know it needs good seed dispersal, but a designer obviously would recognize the need. Another biomimetic design to help our engineers.