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Comment by Dr. Krishna Kumari Challa on November 24, 2020 at 9:47am

When food is scarce, members of a species of forest-dwelling bacteria come together to build structures called fruiting bodies to survive until food becomes more available. Princeton researchers have identified how these bacteria harness the same physical laws that lead to the whorls of a fingerprint to build the structures, which consist of the bacterial cells themselves and secretions that glue the edifice together. The structures are about a tenth of a millimeter high, or tens to hundreds of times taller than a single bacterial cell. On the human scale, this size compares to the height of a skyscraper. Credit: Cassidy Yang, Princeton University

Topological defects promote layer formation in Myxococcus xanthus colonies, Nature Physics (2020). DOI: 10.1038/s41567-020-01056-4 , www.nature.com/articles/s41567-020-01056-4

https://phys.org/news/2020-11-social-bacteria-physics-fingerprints....

Comment by Dr. Krishna Kumari Challa on November 24, 2020 at 9:46am

Social bacteria build shelters using the physics of fingerprints

Forest-dwelling bacteria known for forming slimy swarms that prey on other microbes can also cooperate to construct mushroom-like survival shelters known as fruiting bodies when food is scarce. Now a team at Princeton University has discovered the physics behind how these rod-shaped bacteria, which align in patterns like those on fingerprint whorls and liquid crystal displays, build the layers of these fruiting bodies.

( See pic above )

In some ways, these bacteria  are teaching us new kinds of physics. These questions exist at the intersection of physics and biology. And you need to understand both to understand these organisms.

Myxococcus xanthus, or Myxo for short, is a bacterial species capable of surprisingly cooperative behaviors. For example, large numbers of Myxo cells  come together to hunt other bacteria by swarming toward their prey in a single undulating mass.

When food is scarce, however, the rod-like cells stack atop one another to form squishy growths called fruiting bodies, which are hideaways in which some of the Myxo cells transform into spores capable of rebooting the population when fresh nutrients arrive. But until now, scientists haven't understood how the rods acquire the ability to begin climbing on top of each other to build the droplet-like structures.

To find out more about how these bacteria behave, the researchers set up a microscope capable of tracking Myxo's actions in three dimensions. The scientists recorded videos of the rod-shaped microbes, which pack closely together like stampeding wildebeest, rushing across the microscope dish in swaths that swirl around each other, forming fingerprint-like patterns.

When two swaths meet, the researchers observed, the point of intersection was exactly where the new layer of cells started to form. The bacteria started to pile up and created a situation where the only direction to go was up. these bacteria are exploiting particular points of the cell alignment where stresses build that enable the colony to construct new cell layers, one on top of the other. And that's ultimately how this colony responds to starvation. Researchers call the points where the massing cells collide "topological defects," a term that refers to the mathematics that describe these singular points. Topology is the branch of mathematics that finds similarities between objects such as teacups and donuts, because one can be stretched or deformed into the other.

Myxo bacterial cells behave much like liquid crystals, the fluids found in smartphone screens, which are made of rod-shaped molecules. Unlike passive liquid crystals, however, Myxo rods are alive and can crawl. The bacteria most likely have evolved to take advantage of both passive and active factors to build the fruiting bodies.

The combination of physics and biology training among the researchers enabled them to recognize new theoretical insights into how the vertical layers form.

Comment by Dr. Krishna Kumari Challa on November 24, 2020 at 9:43am

Previewed Reality: A system that allows users to predict future changes in their environment

When robots and humans interact in a shared environment, it is important for them to move in ways that prevent collisions or accidents. To reduce the risk of collisions, roboticists have developed numerous of techniques that monitor an environment, predict the future actions of humans moving in it, identify safe trajectories for a robot and control its movements accordingly.

Researchers at Kyushu University in Japan recently created a system that allows human users to forecast future changes in their environment, which could then inform their decisions and guide their actions. 

To collect information about the position of different objects, robots and humans in a shared environment, the researchers used a number of strategically placed sensors, including optical trackers and an RGB-D camera. The optical trackers monitored the movements of objects or robots, while the RGB-D camera mainly tracked human actions.

The data gathered by the sensors was then fed to a motion planner and a dynamics simulator. Combined, these two system components allowed the researchers to forecast changes in a given environment and synthesize images of events that are likely to occur in the near future, from the viewpoint of a specific human.

Human users could then view these synthesized images simply by wearing a VR headset or an AR display. On the headset or display, the images were layed over those of a user's actual surroundings, in order to clearly illustrate the changes that could take place in the future.

Asuka Egashira et al. Near-future perception system: Previewed Reality, Advanced Robotics (2020). DOI: 10.1080/01691864.2020.1829041

https://techxplore.com/news/2020-11-previewed-reality-users-future-...

Comment by Dr. Krishna Kumari Challa on November 23, 2020 at 11:25am

**Virus evolution could undermine a COVID-19 vaccine – but this can be stopped

https://theconversation.com/virus-evolution-could-undermine-a-covid...

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Ultrasound Reveals Parasitic Worms Squirming Around Inside Man's Stomach in Delhi

Nightmare Ultrasound Reveals Parasitic Worms Squirming Around Inside Man's Stomach

An ultrasound of a man's stomach captured some unwelcome inhabitants - a tangle of parasitic roundworms squirming around, according to a new report.

https://www.sciencealert.com/nightmare-ultrasound-reveals-parasitic...

Comment by Dr. Krishna Kumari Challa on November 23, 2020 at 10:04am

Fake news and misinformation kill: How can you trust what you are told about Covid-19?

EXPERT ADVISORY: Fake news and misinformation kill: How can you trust what you are told about Covid-19?

In the past 10 months, as Covid-19 has swept the globe, the internet and media have also been ablaze with stories, reports and ever-changing guidelines on how to stay safe in a world that appears to be out of control. But what should we believe and what can we trust? As importantly, how do we spot ‘fake news’ and misinformation? In this special advisory, a collective of over 20 of SA’s leading doctors and scientists offer their advice.

https://www.dailymaverick.co.za/article/2020-11-22-fake-news-and-mi...

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MIT biologists solve vitamin puzzle

Vitamin B12 is produced by soil microbes that live in symbiotic relationships with plant roots

https://news.mit.edu/2007/b12

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Natural Fires can kindle biodiversity, sparking new approaches to conservation

Comment by Dr. Krishna Kumari Challa on November 23, 2020 at 9:55am

Astronomers discover new 'fossil galaxy' buried deep within the Milky Way

Scientists working with data from the Sloan Digital Sky Surveys' Apache Point Observatory Galactic Evolution Experiment (APOGEE) have discovered a "fossil galaxy" hidden in the depths of our own Milky Way.

The proposed fossil galaxy may have collided with the Milky Way ten billion years ago, when our galaxy was still in its infancy. Astronomers named it Heracles, after the ancient Greek hero who received the gift of immortality when the Milky Way was created.

The remnants of Heracles account for about one third of the Milky Way's spherical halo. But if stars and gas from Heracles make up such a large percentage of the galactic halo, why didn't we see it before? The answer lies in its location deep inside the Milky Way.

"To find a fossil galaxy like this one, we had to look at the detailed chemical makeup and motions of tens of thousands of stars. That is especially hard to do for stars in the center of the Milky Way, because they are hidden from view by clouds of interstellar dust. APOGEE lets us pierce through that dust and see deeper into the heart of the Milky Way than ever before.

APOGEE does this by taking spectra of stars in near-infrared light, instead of visible light, which gets obscured by dust. Over its ten-year observational life, APOGEE has measured spectra for more than half a million stars all across the Milky Way, including its previously dust-obscured core and finally discovered this fossil galaxy .

"Evidence from APOGEE for the Presence of a Major Building Block of the Halo Buried in the Inner Galaxy," Danny Horta et al., 2020 Nov. 20, Monthly Notices of the Royal Astronomical Society: arxiv.org/abs/2007.10374].

https://phys.org/news/2020-11-astronomers-fossil-galaxy-deep-milky....

Comment by Dr. Krishna Kumari Challa on November 22, 2020 at 10:12am

3D-printed, lifelike heart models could help train tomorrow’s surgeons

Comment by Dr. Krishna Kumari Challa on November 21, 2020 at 10:55am

** Asymptomatic Children Can Spread Malaria to Mosquitoes

Children infected with malaria can become 'superspreaders' and pass the parasite to droves of local mosquitoes, even if the kids never develop symptoms of the disease, a new study suggests. 

Since this disease is passed from humans to mosquitoes and then back again, rather than from person to person, this finding is worrisome. If malaria goes untreated in these asymptomatic children, the parasites will continue to circulate among mosquitoes, even in places that employ intensive malaria controls like insecticides, bednets, and free diagnostic tests and treatments. According to new research, presented Wednesday (Nov. 18) at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH), even a small number of infected children can transmit malaria parasites to a mob of mosquitoes, which can then go on to infect more humans. From their new research in Uganda, the researchers concluded that asymptomatic children between ages 5 and 15 are the main source of infection for local mosquitoes in the region they studied. Some of these children were so-called superspreaders, meaning they infected a much larger number of mosquitoes than others; in experiments where mosquitoes were fed blood samples from infected people, more than 60 percent of the resulting mosquito infections could be traced back to just four asymptomatic children, two of whom were school-age. The other two superspreaders were ages 3 and 4.

Despite some children becoming infected with multiple malaria clones during the study, these kids never fell ill and continued to lead a "normal life … somehow living with all these parasites

https://www.livescience.com/asymptomatic-children-malaria-reservoir...

Comment by Dr. Krishna Kumari Challa on November 21, 2020 at 10:52am

**In a First, Scientists Say They've Partially Reversed a Cellular Aging Process in Humans

Every time a cell inside your body replicates, a slither of your youth crumbles to dust. This occurs via the shortening of telomeres, structures that 'cap' the tips of our chromosomes.

Now, scientists in Israel say they've been able to reverse this process and extend the length of telomeres in a small study involving 26 patients.

The participants sat in a hyperbaric oxygen chamber for five 90 minutes sessions per week over three months, and as a result, some of their cell's telomeres were extended by up to 20 percent.

It's an impressive claim - and something many other researchers have attempted in the past without success. But of course it's worth flagging that this is a small sample size, and the results will need to be replicated before we can get too excited. 

However, the fact that hyperbaric oxygen therapy appears to affect telomere length is a compelling link worth investigating further. 

Telomeres are repeating chunks of code that act as the DNA equivalent of the plastic or metal aglet capping the end of a shoelace.

They copy themselves along with the rest of the chromosomes whenever a cell divides. Yet with every replication, tiny fragments of code from the very tip of the sequence fail to make it into the new copy, leaving the freshly minted chromosome a touch shorter than its predecessor.

As anybody who has lost the cap of their shoelace knows, it doesn't take long for the shoelace to lose its integrity. Similarly, shorter telomeres put sequences further down the chromosome at higher risk of hazardous mutations.

These mutations coincide with changes that predispose us to a bunch of age-related conditions, not least of all diseases such as cancer.

That's not necessarily to say that we age because our telomeres shrink, but there is a connection between telomere length and health that researchers are keen to investigate further.

"Longer telomeres correlates with better cellular performance. There are plenty of ways to accelerate the erosion of our telomeres. Failing to get adequate sleep could do it, as might chowing down on too much processed food, and maybe even having kids.
Slowing down the loss takes a bit more effort, but engaging in regular exercise and eating well are sound bets if you want your chromosomes to remain as long as possible.

A real achievement would be to flip our chromosomal hourglass completely and return lost sections of telomere. The fact that high-turnover tissues lining our gut do this naturally using an enzyme called telomerase has fuelled research over the years.

There have been plenty of milestones in attempts to achieve this task. Gene therapy in mice has shown it could one day be feasible in humans. More recently, stem cells from a supercentenarian woman had their telomeres completely reset outside of her body.

Some studies have found potential for tiny increases of maybe a few percent with provision of nutritional supplements such as vitamin D.

https://www.aging-us.com/article/202188/text

https://www.sciencealert.com/oxygen-therapy-found-to-turn-back-the-...

Comment by Dr. Krishna Kumari Challa on November 21, 2020 at 7:35am

How rotavirus causes severe gastrointestinal disease

Rotavirus is a major cause of diarrhea and vomiting, especially in children, that results in approximately 128,000 deaths annually. The virus triggers the disease by infecting enterocyte cells in the small intestine, but only a fraction of the susceptible cells has the virus. In the mid-90s, scientists proposed that the small portion of infected cells promotes severe disease by sending out signals that disrupt the normal function of neighbouring uninfected cells, but the nature of the signal has remained a mystery.

In the current study published in the journal Science, a team led by researchers at Baylor College of Medicine discovered that rotavirus-infected cells release signaling molecules, identified as adenosine diphosphate (ADP), which binds its cellular receptor P2Y1 on neighboring cells. Activating P2Y1 by ADP results in signals called intercellular calcium waves in these uninfected cells. Disrupting ADP binding to its receptor reduced the severity of diarrhea in a mouse model of the disease, suggesting that targeting the P2Y1 may be an effective strategy to control viral diarrhea in human populations.

Further studies revealed previously unknown roles of ADP on rotavirus infection and replication, shining a spotlight on ADP as an important trigger of the multiple factors involved in severe diarrhea and vomiting caused by rotavirus. For instance, the researchers found evidence that ADP signaling increases rotavirus infection, the expression of inflammatory cytokine IL1-alpha and the secretion of serotonin, an inducer of diarrhea. ADP signaling also increases the expression of enzymes that produce prostaglandin and nitric oxide, potentially causing the increases in those compounds observed in rotavirus infection. Preventing ADP signaling and intercellular calcium waves reduced the production of the compounds mentioned above.

 Alexandra L. Chang-Graham et al, Rotavirus induces intercellular calcium waves through ADP signaling, Science (2020). DOI: 10.1126/science.abc3621

https://medicalxpress.com/news/2020-11-rotavirus-severe-gastrointes...

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