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Comment by Dr. Krishna Kumari Challa on January 16, 2021 at 8:56am

Scientists identify nutrient that helps prevent bacterial infection

Scientists studying the body's natural defenses against bacterial infection have identified a nutrient—taurine—that helps the gut recall prior infections and kill invading bacteria, such as Klebsiella pneumoniae (Kpn). The finding, published in the journal Cell by scientists could aid efforts seeking alternatives to antibiotics.

Scientists know that microbiota—the trillions of beneficial microbes living harmoniously inside our gut—can protect people from bacterial infections, but little is known about how they provide protection. Scientists are studying the microbiota with an eye to finding or enhancing natural treatments to replace antibiotics, which harm microbiota and become less effective as bacteria develop drug resistance. 

The scientists observed that microbiota that had experienced prior infection and transferred to germ-free mice helped prevent infection with Kpn. They identified a class of bacteria—Deltaproteobacteria—involved in fighting these infections, and further analysis led them to identify taurine as the trigger for Deltaproteobacteria activity.

Taurine helps the body digest fats and oils and is found naturally in bile acids in the gut. The poisonous gas hydrogen sulfide is a byproduct of taurine. The scientists believe that low levels of taurine allow pathogens to colonize the gut, but high levels produce enough hydrogen sulfide to prevent colonization. During the study, the researchers realized that a single mild infection is sufficient to prepare the microbiota to resist subsequent infection, and that the liver and gallbladder—which synthesize and store bile acids containing taurine—can develop long-term infection protection.

The study found that taurine given to mice as a supplement in drinking water also prepared the microbiota to prevent infection. However, when mice drank water containing bismuth subsalicylate—a common over-the-counter drug used to treat diarrhea and upset stomach—infection protection waned because bismuth inhibits hydrogen sulfide production.

A Stacy et al. Infection trains the host for microbiota-enhanced resistance to pathogens. Cell, DOI: 10.1016/j.cell.2020.12.011 (2021).

https://phys.org/news/2021-01-scientists-nutrient-bacterial-infecti...

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Comment by Dr. Krishna Kumari Challa on January 16, 2021 at 8:42am

Snakes evolve a magnetic way to be resistant to venom

Certain snakes have evolved a unique genetic trick to avoid being eaten by venomous snakes, according to new research. the technique worked in a manner similar to the way two sides of a magnet repel each other.

The target of snake venom neurotoxins is a strongly negatively charged nerve receptor.

This has caused neurotoxins to evolve with positively charged surfaces, thereby guiding them to the neurological target to produce paralysis.

"But some snakes have evolved to replace a negatively charged amino acid on their receptor with a positively charged one, meaning the neurotoxin is repelled.

It's an inventive genetic mutation and it's been completely missed until now. this trait has evolved at least 10 times in different species of snakes. 

The researchers found that the Burmese python—a slow-moving terrestrial species vulnerable to predation by cobras—is extremely neurotoxin resistant. Similarly, the South African mole snake, another slow-moving snake vulnerable to cobras, is also extremely resistant. 

But Asian pythons which live in trees as babies, and Australian pythons which do not live alongside neurotoxic snake-eating snake, do not have this resistance.

We've long known that some species—like the mongoose—are resistant to snake venom through a mutation that physically blocks neurotoxins by having a branch-like structure sticking out of the receptor, but this is the first time the magnet-like effect has been observed.

It has also evolved in venomous snakes to be resistant to their own neurotoxins on at least two occasions.

 Richard J. Harris et al. Electrostatic resistance to alpha-neurotoxins conferred by charge reversal mutations in nicotinic acetylcholine receptors, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2020.2703

https://phys.org/news/2021-01-snakes-evolve-magnetic-resistant-veno...

Comment by Dr. Krishna Kumari Challa on January 16, 2021 at 8:16am

Future homes could be made of living fungus

Mushroom house: a 'tiny house' out of mushrooms - Mushroom Tiny House, a 64-square-foot home designed by Ecovative Design that uses mycelium -- a type of fungi -- to literally grow the structure from the inside out.

There are two principal advantages to this. First, living fungus might behave as a self-healing material, simply re-growing if it becomes damaged. Second, mycelium networks are capable of information processing. Electrical signals run through them and change over time in a manner almost akin to a brain. Fungal materials respond to tactile stimulation and illumination by changing their patterns of electrical activity.

https://phys.org/news/2021-01-future-homes-fungus.html?utm_source=n...

Comment by Dr. Krishna Kumari Challa on January 15, 2021 at 12:42pm

Cellular autofluorescence is magnetic field sensitive

How cells might sense Earth’s magnetic field

Glowing cells offer clues to the mysterious mechanism that animals such as birds, bats, eels and whales might use to navigate using Earth’s magnetic field. Cryptochrome, a protein found in plants and animals that can absorb light and emit an electromagnetic signal, has been a prime suspect for the source of magnetoreception — the ability to detect magnetic fields. Using a specialized microscope, scientists irradiated human cells, which caused cryptochromes to fluoresce. But when the researchers passed magnets over the cells, the fluorescence dropped. It’s the first time that cryptochromes have been observed responding to magnetic fields in a living cell.

https://www.pnas.org/content/118/3/e2018043118?utm_source=Nature+Br...

The radical pair mechanism is the favored hypothesis for explaining biological effects of weak magnetic fields, such as animal magnetoreception and possible adverse health effects. To date, however, there is no direct experimental evidence for magnetic effects on radical pair reactions in cells, the fundamental building blocks of living systems. In this paper, using a custom-built microscope, we demonstrate that flavin-based autofluorescence in native, untreated HeLa cells is magnetic field sensitive, due to the formation and electron spin–selective recombination of spin-correlated radical pairs. This work thus provides a direct link between magnetic field effects on chemical reactions measured in solution and chemical reactions taking place in living cells.

Comment by Dr. Krishna Kumari Challa on January 15, 2021 at 9:58am

How aerosols are formed

Researchers recently conducted an experiment to investigate the initial steps in the formation of aerosols. Their findings are now aiding efforts to better understand and model that process—for example, the formation of clouds in the atmosphere.

Aerosols are suspensions of fine solid particles or liquid droplets in a gas. Clouds, for example, are aerosols because they consist of water droplets dispersed in the air. Such droplets are produced in a two-step process: first, a condensation nucleus forms, and then volatile molecules condense onto this nucleus, producing a droplet. Nuclei frequently consist of molecules different to those that condense onto them. In the case of clouds, the nuclei often contain sulphuric acids and organic substances. Water vapor from the atmosphere subsequently condenses onto these nuclei.

Scientists l have now gained new insights into the first step of aerosol formation, nucleation. Observations have shown that the volatile components can also influence the nucleation process but what was unclear was how this was happening at the molecular level. Previously it was impossible to observe the volatile components during nucleation in an experimental setting. Even in a famous CERN experiment on cloud formation, certain volatile components could not be directly detected.

The ETH researchers developed an experiment aimed at the first microseconds of the nucleation process. In the experiment, the particles formed remain intact during this time and can be detected using mass spectrometry. The scientists looked at nucleation in various gas mixtures containing CO₂ and for the first time, they were able to detect the volatile components as well—in this case, the CO₂. The researchers could show that the volatile components were essential for the formation of nuclei and also accelerated this process.

An analysis of the experimental data revealed that this acceleration is the result of the volatile components catalyzing the nucleation of other, less volatile components. They do this by forming short-lived, heterogeneous molecular aggregates, known as chaperon complexes. Because temperature determines the volatility of gas components, it also plays a decisive role in these processes.

Chenxi Li et al. How volatile components catalyze vapor nucleation, Science Advances (2021). DOI: 10.1126/sciadv.abd9954

https://phys.org/news/2021-01-aerosols.html?utm_source=nwletter&...

Comment by Dr. Krishna Kumari Challa on January 15, 2021 at 9:49am

Sexual harassment claims considered more credible if made by 'prototypical' women

Women who are young, "conventionally attractive" and appear and act feminine are more likely to be believed when making accusations of sexual harassment, a new University of Washington-led study finds. 

 That leaves women who don't fit the prototype potentially facing greater hurdles when trying to convince a workplace or court that they have been harassed.

The study, involving more than 4,000 participants, reveals perceptions that primarily "prototypical" women are likely to be harassed. The research also showed that women outside of those socially determined norms—or "nonprototypical" women—are more likely perceived as not being harmed by harassment.

The consequences of that are very severe for women who fall outside of the narrow representation of who a victim is .

 Nonprototypical women are neglected in ways that could contribute to them having discriminatory treatment under the law; people think they're less credible—and less harmed—when they make a claim, and think their perpetrators deserve less punishment.

Journal of Personality and Social Psychology (2021). DOI: 10.1037/pspi0000260  

https://medicalxpress.com/news/2021-01-sexual-credible-prototypical...

Comment by Dr. Krishna Kumari Challa on January 15, 2021 at 9:44am

Scientists discover the secret of Galapagos' rich ecosystem

New research has unlocked the mystery of how the Galápagos Islands, a rocky, volcanic outcrop, with only modest rainfall and vegetation, is able to sustain its unique wildlife habitats.

The Galápagos archipelago, rising from the eastern equatorial Pacific Ocean some 900 kilometres off the South American mainland, is an iconic and globally significant biological hotspot. The islands are renowned for their unique wealth of endemic species, which inspired Charles Darwin's theory of evolution and today underpins one of the largest UNESCO World Heritage Sites and Marine Reserves on Earth.

Scientists have known for decades that the regional ecosystem is sustained by upwelling of cool, nutrient-rich deep waters, which fuel the growth of the phytoplankton upon which the entire ecosystem thrives.

Yet despite its critical life-supporting role, the upwelling's controlling factors had remained undetermined prior to this new study. Establishing these controls, and their climate sensitivity, is critical to assessing the resilience of the regional ecosystem against modern climatic change.

In this new research, published in Scientific Reports, scientists  used a realistic, high-resolution computer model to study the regional ocean circulation around the Galápagos Islands.

This model showed that the intensity of upwelling around the Galápagos is driven by local northward winds, which generate vigorous turbulence at upper-ocean fronts to the west of the islands. These fronts are areas of sharp lateral contrasts in ocean temperature, similar in character to atmospheric fronts in weather maps, but much smaller.

The turbulence drives upwelling of deep waters toward the ocean surface, thus providing the nutrients needed to sustain the Galápagos ecosystem. Galápagos upwelling is controlled by highly localised atmosphere-ocean interactions. There now needs to be a focus on these processes when monitoring how the islands' ecosystem is changing, and in mitigating the ecosystem's vulnerability to 21st -century climate change.

Scientific Reports (2021). DOI: 10.1038/s41598-020-80609-2

https://phys.org/news/2021-01-scientists-secret-galapagos-rich-ecos...

Comment by Dr. Krishna Kumari Challa on January 15, 2021 at 9:08am

Models to analyse 'viral escape'

Model analyzes how viruses escape the immune system

One reason it's so difficult to produce effective vaccines against some viruses, including influenza and HIV, is that these viruses mutate very rapidly. This allows them to evade the antibodies generated by a particular vaccine, through a process known as "viral escape."

Researchers have now devised a new way to computationally model viral escape, based on models that were originally developed to analyze language. The model can predict which sections of viral surface proteins are more likely to mutate in a way that enables viral escape, and it can also identify sections that are less likely to mutate, making them good targets for new vaccines.

Viral escape of the surface protein of influenza and the envelope surface protein of HIV are both highly responsible for the fact that we don't have a universal flu vaccine, nor do we have a vaccine for HIV, both of which cause hundreds of thousands of deaths a year.

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B. Hie el al., "Learning the language of viral evolution and escape," Science (2020). science.sciencemag.org/cgi/doi … 1126/science.abd7331

Y.-A. Kim el al., "The language of a virus," Science (2020). science.sciencemag.org/cgi/doi … 1126/science.abf6894

https://phys.org/news/2021-01-viruses-immune.html?utm_source=nwlett...

Comment by Dr. Krishna Kumari Challa on January 14, 2021 at 11:57am

These tiny oceanic creatures are essential to tackling climate change

The ocean withdraws about one third of the CO₂ in the atmosphere, mitigating climate change and making life possible on Earth. An important share of this CO2 is removed thanks to phytoplankton, tiny marine creatures that use light to do photosynthesis, just as plants or trees on land. These cells fix CO2 to build up biomass and multiply, and take it down to the deep ocean when they die and sink. Phytoplankton are thus the basis of the marine food chain, and their productivity not only affects CO2 levels, but also fish catch and world economy.

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Wormholes may be lurking in the universe—and new studies are propos...

Albert Einstein's theory of general relativity profoundly changed our thinking about fundamental concepts in physics, such as space and time. But it also left us with some deep mysteries. One was black holes, which were only unequivocally detected over the past few years. Another was "wormholes"—bridges connecting different points in spacetime, in theory providing shortcuts for space travelers.

Comment by Dr. Krishna Kumari Challa on January 14, 2021 at 11:56am

Researchers at Brazil's space institute discover why lightning branches and flickers

Researchers have recorded for the first time the formation and branching of luminous structures by lightning strikes.

Analyzing images captured by a super slow motion camera, they discovered why lightning strikes bifurcate and sometimes then form luminous structures interpreted by the human eye as flickers.

The researchers used ultra high speed digital video cameras to record more than 200 upward flashes during summer thunderstorms in São Paulo City (Brazil) and Rapid City, South Dakota (USA) between 2008 and 2019. Upward lightning strikes start from the top of a tall building or other ground-based structure and propagate upward to the overlying cloud.

The upward flashes they recorded were triggered by positively charged cloud-to-ground lightning discharges, which are much more common, as described by the same INPE research group in a previous study.

"Upward lightning originates at the top of a tower or the lightning conductor on a skyscraper, for example, when the storm's electrical field is disturbed by a cloud-to-ground discharge as far away as 60 kilometers.

Although the study conditions were very similar in Brazil and the US, luminous structures were observed in only three upward flashes, recorded in the US. These were formed by a positive leader discharge propagating toward the cloud base.

"The advantage of recording images of upward lightning is that they let us see the entire trajectory of these positive leaders from ground to cloud base. Once inside the cloud, they can no longer be seen.

The researchers found that a low-luminosity discharge with a structure resembling a paintbrush sometimes forms at the tip of the positive leader. It was observed that this discharge, often referred to as a corona brush, may change direction, split in two, and define the path of the lightning flash and how it branches.

When an upward flash branches successfully, it may proceed to the left or right. When branching fails, the corona brush may give rise to very short segments as bright as the leader itself. These segments first appear milliseconds after the corona brush splits, and pulsate as the leader propagates upward toward the cloud base, the videos show.

The flickers are recurring failed attempts to start a branch, the flickers may explain why multiple lightning discharges are frequent, but more studies are needed to verify this theory.

Marcelo M. F. Saba et al, Optical observation of needles in upward lightning flashes, Scientific Reports (2020). DOI: 10.1038/s41598-020-74597-6

https://phys.org/news/2021-01-brazil-space-lightning-flickers.html?...

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