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Comment by Dr. Krishna Kumari Challa on July 17, 2021 at 9:33am

Just 7% of our DNA is unique to modern humans, study shows

What makes humans unique? Scientists have taken another step toward solving an enduring mystery with a new tool that may allow for more precise comparisons between the DNA of modern humans and that of our extinct ancestors.

Just 7% of our genome is uniquely shared with other humans, and not shared by other early ancestors, according to a study published Friday in the journal Science Advances.

That's a pretty small percentage. This kind of finding is why scientists are turning away from thinking that we humans are so vastly different from Neanderthals.

The research draws upon DNA extracted from fossil remains of now-extinct Neanderthals and Denisovans dating back to around 40,000 or 50,000 years ago, as well as from 279 modern people from around the world.

Scientists already know that modern people share some DNA with Neanderthals, but different people share different parts of the genome. One goal of the new research was to identify the genes that are exclusive to modern humans.

It's a difficult statistical problem, and the researchers developed a valuable tool that takes account of missing data in the ancient genomes.

The researchers also found that an even smaller fraction of our genome—just 1.5%—is both unique to our species and shared among all people alive today. Those slivers of DNA may hold the most significant clues as to what truly distinguishes modern human beings.

Scientists now can tell those regions of the genome are highly enriched for genes that have to do with neural development and brain function.

Nathan K. Schaefer et al, An ancestral recombination graph of human, Neanderthal, and Denisovan genomes, Science Advances (2021). DOI: 10.1126/sciadv.abc0776

https://phys.org/news/2021-07-dna-unique-modern-humans.html?utm_sou...

Comment by Dr. Krishna Kumari Challa on July 17, 2021 at 8:53am

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 10:52am

‘Super-antibodies’ could curb COVID-19 and help avert future pandemics

Companies are designing next-generation antibodies modeled on those taken from unique individuals whose immune systems can neutralize any COVID-19 variant—and related coronaviruses, too.

A new generation of designer antibodies could help to treat a wide range of SARS-CoV-2 variants — and future coronaviruses with pandemic potential. ‘Super-antibodies’ are modelled on antibodies taken from rare individuals whose immune systems can neutralize any SARS-CoV-2 variant and related coronaviruses.

https://www.nature.com/articles/s41587-021-00980-x?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 9:45am

Researchers confirm we may never know how many species have inhabit...

Professors in Syracuse University's College of Arts and Sciences explored whether or not the scientific community will ever be able to settle on a 'total number' of species of living vertebrates, which could help with species preservation. By knowing what's out there, researchers argue that they can prioritize places and groups on which to concentrate conservation efforts.

Bruce H Wilkinson et al, Estimating vertebrate biodiversity using the tempo of taxonomy – a view from Hubbert's peak, Biological Journal of the Linnean Society (2021). DOI: 10.1093/biolinnean/blab080

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 9:40am

Researchers create snake-venom-derived 'super glue' that stops bleeding in seconds 

This super glue is based on a new discovery on a blood clotting enzyme called reptilase or batroxobin found in the venom of lancehead snakes (Bothrops atrox), which are amongst the most poisonous snakes in South America.

Taking advantage of this clotting property, researchers designed a body tissue adhesive that incorporates the special enzyme into a modified gelatin that can be packaged into a small tube for easy, and potentially life-saving, application.

During trauma, injury and emergency bleeding, this 'super glue' can be applied by simply squeezing the tube and shining a visible light, such as a laser pointer, over it for few seconds. Even a smartphone flashlight will do the job.

Compared to clinical fibrin glue, considered the industry gold standard for clinical and field surgeons, the new tissue sealant has 10 times the adhesive strength to resist detachment or washout due to bleeding. The blood clotting time is also much shorter, cutting it in half from 90 seconds for fibrin glue to 45 seconds for the new snake venom "super glue."

This new biotechnology translates to less blood loss and more life-saving. The super-sealant was tested in models for deep skin cuts, ruptured aortae, and severely injured livers—all considered as major bleeding situations.

Yicheng Guo et al, Snake extract–laden hemostatic bioadhesive gel cross-linked by visible light, Science Advances (2021). DOI: 10.1126/sciadv.abf9635

https://phys.org/news/2021-07-snake-venom-derived-super-seconds-vis...

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 9:30am

Part 2: 

The researchers experimented with several variables to see how they impacted Physarum's growth decisions, and noticed something unusual: when they stacked the same three discs on top of each other, the organism seemed to lose its ability to distinguish between the three discs and the single disc. It grew toward both sides of the dish at roughly equal rates, despite the fact that the three stacked discs still had greater mass. Clearly, Physarum was using another factor beyond mass to decide where to grow.

To figure out the missing piece of the puzzle, the scientists used computer modeling to create a simulation of their experiment to explore how changing the mass of the discs would impact the amount of stress (force) and strain (deformation) applied to the semi-flexible gel and the attached growing Physarum. As they expected, larger masses increased the amount of strain, but the simulation revealed that the strain patterns the masses produced changed, depending on the arrangement of the discs.

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But how was it detecting these strain patterns? The scientists suspected it had to do with Physarum's ability to rhythmically contract and tug on its substrate, because the pulsing and sensing of the resultant changes in substrate deformation allows the organism to gain information about its surroundings. 

Advanced Materials (2021). DOI: 10.1002/adma.202008161

https://phys.org/news/2021-07-brain-brainless-slime-molds-reveal.ht...

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 9:29am

Thinking without a brain: Studies in brainless slime molds reveal that they use physical cues to decide where to grow

Scientists  have discovered that a brainless slime mold called Physarum polycephalum uses its body to sense mechanical cues in its surrounding environment, and performs computations similar to what we call "thinking" to decide in which direction to grow based on that information. Unlike previous studies with Physarum, these results were obtained without giving the organism any food or chemical signals to influence its behavior. The study is published in Advanced Materials.

Physarum is interesting because it doesn't have a brain but it can still perform a lot of the behaviours that we associate with thinking, like solving mazes, learning new things, and predicting events. Figuring out how proto-intelligent life manages to do this type of computation gives us more insight into the underpinnings of animal cognition and behavior, including our own.

The team's research demonstrated that this brainless creature was not simply growing toward the heaviest thing it could sense—it was making a calculated decision about where to grow based on the relative patterns of strain it detected in its environment.

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Slime molds are amoeba-like organisms that can grow to be up to several feet long, and help break down decomposing matter in the environment like rotting logs, mulch, and dead leaves. A single Physarum creature consists of a membrane containing many cellular nuclei floating within a shared cytoplasm, creating a structure called a syncytium. Physarum moves by shuttling its watery cytoplasm back and forth throughout the entire length of its body in regular waves, a unique process known as shuttle streaming. With most animals, we can't see what's changing inside the brain as the animal makes decisions. Physarum offers a really exciting scientific opportunity because we can observe its decisions about where to move in real-time by watching how its shuttle streaming behavior changes.

While previous studies have shown that Physarum moves in response to chemicals and light, Murugan and her team wanted to know if it could make decisions about where to move based on physical cues in its environment alone.

The researchers placed Physarum specimens in the center of petri dishes coated with a semi-flexible agar gel and placed either one or three small glass discs next to each other atop the gel on opposite sides of each dish. They then allowed the organisms to grow freely in the dark over the course of 24 hours, and tracked their growth patterns. For the first 12 to 14 hours, the Physarum grew outwards evenly in all directions; after that, however, the specimens extended a long branch that grew directly over the surface of the gel toward the three-disc region 70% of the time. Remarkably, the Physarum chose to grow toward the greater mass without first physically exploring the area to confirm that it did indeed contain the larger object.

Comment by Dr. Krishna Kumari Challa on July 16, 2021 at 9:23am

Human cells harness power of detergents to wipe out bacteria

Cells, like many of us, fend off germs with cleaning products. Researchers have discovered that a molecule made throughout much of the body wipes out invading bacteria like a detergent attacking an oily stain.

This killer cleaner, a protein known as APOL3, thwarts infections by dissolving bacterial membranes. Researchers tested the protein on the food-poisoning bacteria Salmonella and other similar microbes.

The work offers new insight into how human cells defend themselves against infection, a process termed cell-autonomous immunity. While scientists knew that cells could attack bacterial membranes, this study uncovers what appears to be the first example of a protective intracellular protein with detergent-like action.

"A human apolipoprotein L with detergent-like activity kills intracellular pathogens" Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abf8113

https://phys.org/news/2021-07-human-cells-harness-power-detergents....

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Comment by Dr. Krishna Kumari Challa on July 15, 2021 at 10:56am

Glass octopus moving in the deep sea

Marine biologists spotted the elusive glass octopus (Vitreledonella richardi) during a 34-day expedition off the remote Phoenix Islands

Comment by Dr. Krishna Kumari Challa on July 15, 2021 at 10:15am

The Story of Primary Plastid Endosymbiosis: How Algae and Plants became Photosynthetic

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