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Comment by Dr. Krishna Kumari Challa on June 15, 2021 at 11:39am

Microbes in ocean play important role in moderating Earth's temperature

Methane is a strong greenhouse gas that plays a key role in Earth's climate. Anytime we use natural gas, whether we light up our kitchen stove or barbeque, we are using methane.

Only three sources on Earth produce methane naturally: volcanoes, subsurface water-rock interactions, and microbes. Between these three sources, most is generated by microbes, which have deposited hundreds of gigatons of methane into the deep seafloor. At seafloor methane seeps, it percolates upwards toward the open ocean, and microbial communities consume the majority of this methane before it reaches the atmosphere. Over the years, researchers are finding more and more methane beneath the seafloor, yet very little ever leaves the oceans and gets into the atmosphere. Where is the rest going?

A team of researchers now discovered that microbial communities that rapidly consume the methane, preventing its escape into Earth's atmosphere. The study published in Proceedings of the National Academy of Sciences collected and examined methane-eating microbes from seven geologically diverse seafloor seeps and found, most surprisingly, that the carbonate rocks from one site in particular hosts methane-oxidizing microbial communities with the highest rates of methane consumption measured to date.

The microbes in these carbonate rocks are acting like a methane bio filter consuming it all before it leaves the ocean.

Jeffrey J. Marlow el al., "Carbonate-hosted microbial communities are prolific and pervasive methane oxidizers at geologically diverse marine methane seep sites," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2006857118

https://phys.org/news/2021-06-microbes-ocean-important-role-moderat...

Comment by Dr. Krishna Kumari Challa on June 15, 2021 at 11:30am

Dark matter is slowing the spin of the Milky Way's galactic bar

The spin of the Milky Way's galactic bar, which is made up of billions of clustered stars, has slowed by about a quarter since its formation, according to a new study by researchers.

For 30 years, astrophysicists have predicted such a slowdown, but this is the first time it has been measured.

The researchers say it gives a new type of insight into the nature of dark matter, which acts like a counterweight slowing the spin.

Researchers analysed Gaia space telescope observations of a large group of stars, the Hercules stream, which are in resonance with the bar—that is, they revolve around the galaxy at the same rate as the bar's spin.

These stars are gravitationally trapped by the spinning bar. The same phenomenon occurs with Jupiter's Trojan and Greek asteroids, which orbit Jupiter's Lagrange points (ahead and behind Jupiter). If the bar's spin slows down, these stars would be expected to move further out in the galaxy, keeping their orbital period matched to that of the bar's spin.

The researchers found that the stars in the stream carry a chemical fingerprint—they are richer in heavier elements (called metals in astronomy), proving that they have traveled away from the galactic center, where stars and star-forming gas are about 10 times as rich in metals compared to the outer galaxy.

Using this data, the team inferred that the bar—made up of billions of stars and trillions of solar masses—had slowed down its spin by at least 24% since it first formed.

The counterweight slowing this spin must be dark matter. Until now, researchers  have only been able to infer dark matter by mapping the gravitational potential of galaxies and subtracting the contribution from visible matter.

This new research provides a new type of measurement of dark matter—not of its gravitational energy, but of its inertial mass (the dynamical response), which slows the bar's spin.

 Rimpei Chiba et al, Tree-ring structure of Galactic bar resonance, Monthly Notices of the Royal Astronomical Society (2021). DOI: 10.1093/mnras/stab1094

https://phys.org/news/2021-06-dark-milky-galactic-bar.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on June 14, 2021 at 12:28pm

A 36-year-old woman in South Africa with HIV carried Covid for 216 days, during which Covid viruses accumulated 32 mutations - 13 to the spike protein (could help Covid viruses escape immune responses).

If more such cases are found, it raises the prospect that HIV infection could be a source of new variants simply because the patients could carry the virus for longer.

Scientists only spotted this case because she was enrolled in a study of 300 people with HIV looking at their immune response to Covid.

The researchers also found that four other people with HIV had carried the coronavirus for longer than a month.

…there have been reported cases of people with kidney transplants testing positive for almost a year.

The finding could be of particular importance for Africa, which had about 26 million people living with HIV in 2020. The WHO on Friday warned that a sharp rise in COVID-19 cases could turn into a continentwide third wave of Covid.

https://www.krisp.org.za/publications.php?pubid=336

https://www.businessinsider.in/science/news/a-woman-with-hiv-had-th...

Comment by Dr. Krishna Kumari Challa on June 14, 2021 at 7:42am

Russel's Tea pot and the thought experiment

A quick explanation of Russell's Teapot, a thought experiment demonstrating that the burden of proof rests on the claimant.

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Comment by Dr. Krishna Kumari Challa on June 12, 2021 at 9:47am

South African worker honeybees reproduce by making near-perfect clones of themselves

A team of researchers  has found that workers in a species of honeybee found in South Africa reproduce by making near-perfect clones of themselves.

Prior research has found that some creatures reproduce through parthenogenesis, in which individuals reproduce without mating. This form of reproduction has the advantage of not wasting time and energy on mating and the gene pool remains undiluted. The downside, of course, is loss of genetic diversity, which helps species survive in changing conditions. Prior research has also shown that for most species, parthenogenesis is a less-than-perfect way to produce offspring. This is because some tiny bit of genetic material is generally mixed wrong—these mistakes, known as recombinations, can lead to birth defects or non-productive eggs. In this new effort, the researchers have found a kind of honeybee that has developed a way to avoid recombinations.

The researchers found that South African Cape honeybee queens reproduce sexually, but the workers reproduce asexually.

They then conducted a small experiment—they affixed tape to the reproductive organs of a queen, preventing males from mating with her, and then allowed both her and the worker bees in the same hive to reproduce asexually. They then tested the degree of recombination in both. They found that offspring of the queen had approximately 100 times as much recombination as the worker bees. Even more impressive, the offspring of the worker bees were found to be nearly identical clones of their parent. More testing showed that one line of worker bees in the hive had been cloning themselves for approximately 30 years—a clear sign that workers in the hive were not suffering from birth defects or an inability to produce viable offspring. It also showed that they have evolved a means for preventing recombination when they reproduce. The researchers note that despite their unique abilities, the bees are still in line with evolutionary theory—they are simply doing what works best for their continued existence.

 Benjamin P. Oldroyd et al, Adaptive, caste-specific changes to recombination rates in a thelytokous honeybee population, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.0729

https://phys.org/news/2021-06-south-african-worker-honeybees-near-p...

Comment by Dr. Krishna Kumari Challa on June 12, 2021 at 9:35am

New discovery shows human cells can write RNA sequences into DNA

Cells contain machinery that duplicates DNA into a new set that goes into a newly formed cell. That same class of machines, called polymerases, also build RNA messages, which are like notes copied from the central DNA repository of recipes, so they can be read more efficiently into proteins. But polymerases were thought to only work in one direction DNA into DNA or RNA. This prevents RNA messages from being rewritten back into the master recipe book of genomic DNA. Now, researchers provide the first evidence that RNA segments can be written back into DNA, which potentially challenges the central dogma in biology and could have wide implications affecting many fields of biology.

Polθ reverse transcribes RNA and promotes RNA-templated DNA repair, Science Advances (2021). DOI: 10.1126/sciadv.abf1771

https://phys.org/news/2021-06-discovery-human-cells-rna-sequences.h...

Comment by Dr. Krishna Kumari Challa on June 12, 2021 at 6:41am

Comment by Dr. Krishna Kumari Challa on June 11, 2021 at 11:52am

Bodies May Treat Fast Food Like a Dangerous Infection

The immune system can respond to a fast food diet in much the same way it does to a bacterial infection, according to a 2018 study on mice, raising new questions about just how damaging regular trips to burger and pizza chains could be to our health.

Mice fed the equivalent of a "Western diet" high in saturated fats, sugar, and salt for a month, with nothing in the way of fresh fruit, vegetables, or fibre, were shown to increase the number of immune cells in their blood, just as they would if they'd been hit by a microbial infection.

What's more, this aggressive state of alarm that fast food triggers could stick around for the long term, said the international team of researchers – that's based on recent research into the way our immune systems can remember aspects of past battles they've fought.

Those white blood cells pointed the scientists towards certain genes that were activated by the mouse diets, genes containing progenitor cells – the types of cells responsible for raising up an immune cell army.

That genetic breadcrumb trail matters, because it's these progenitor cells that have previously been found to have a kind of memory in dealing with biological attack.

In other words, once the body has started to react to a fast food diet, returning to a healthy eating regime may not be enough to completely undo the changes, and that's got some implications for our overall health.

Indeed, when the mice went back to their regular cereal diet after a month, the inflammation disappeared – but the genetic reprogramming that kept the mice more sensitive to a future attack stuck around.

https://www.cell.com/cell/fulltext/S0092-8674(17)31493-9

https://www.sciencealert.com/bodies-may-treat-a-western-diet-like-a...

https://www.sciencealert.com/bodies-may-treat-a-western-diet-like-a...

Comment by Dr. Krishna Kumari Challa on June 11, 2021 at 10:51am

The mere sight of illness may kick-start a canary’s immune system

Simply seeing another bird get sick is enough to trigger an immune response in healthy birds

For canaries, just seeing their feathered friends get sick may be enough to preemptively rev up their immune systems.

Healthy birds housed within view of fellow fowl infected with a common pathogen mounted an immune response, despite not being infected themselves, researchers report online June 9 in Biology Letters. 

It’s fascinating that some sort of visual cue could alter immune function.

one experiment in humans found that a mere photo of a sick person increases the activity of inflammation-stimulating chemicals called cytokines. But no one had ever looked to see whether being within eyeshot of an actually sick individual could compel the immune system to preemptive action.

In the experiments researchers conducted,  as healthy birds witnessed neighbors becoming visibly sick, their immune systems stirred. A measure of the birds’ ability to burst foreign cells, called CH50 complement activity, rose in conjunction with how sick the infected birds appeared. White blood cell counts were also significantly different in birds exposed to sick individuals, rather than healthy ones. Cytokine levels did not differ between the two groups.

Blood tests showed that no healthy birds caught MG during the experiment, suggesting that some sort of external cue altered immune function. That cue was likely visual.

A.C. Love et al. Perception of infection: disease-related social cues influence immu.... Biology Letters. Published online June 9, 2021. doi: 10.1098/rsbl.2021.0125.

https://www.sciencenews.org/article/canary-immune-system-sight-illn...

Comment by Dr. Krishna Kumari Challa on June 11, 2021 at 9:29am

Physicists dream big with an idea for a particle collider on the moon

A lunar particle accelerator could reach 1,000 times the energy of Earth’s largest collider

A very high energy hadron collider on the Moon

A particle collider encircling the moon could reach an energy of 14 quadrillion electron volts, physicists report June 6 at arXiv.org. That’s about 1,000 times the energy of the world’s biggest particle accelerator, the Large Hadron Collider, or LHC, at CERN near Geneva.

Such a fantastical machine would probably be buried under the moon’s surface to avoid wild temperature swings, the researchers say, and could be powered by a ring of solar panels around the moon.

https://arxiv.org/abs/2106.02048

https://www.sciencenews.org/article/moon-particle-collider-accelera...

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