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Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:03am

Scientists figure out why there are so many colorful birds in the tropics and how these colours spread over time

The color palette of the birds you see out your window depends on where you live. If you're far from the Equator, most birds tend to have drab colors, but the closer you are to the tropics, you'll probably see more and more colorful feathers.

Scientists have long been puzzled about why there are more brilliantly-colored birds in the tropics than in other places, and they've also wondered how those brightly-colored birds got there in the first place: that is, if those colorful feathers evolved in the tropics, or if tropical birds have colorful ancestors that came to the region from somewhere else.

In a study published in the journal Nature Ecology and Evolution, scientists built a database of 9,409 birds to explore the spread of color across the globe.

They found that iridescent, colorful feathers originated 415 times across the bird tree of life, and in most cases, arose outside of the tropics– and that the ancestor of all modern birds likely had iridescent feathers, too.

There are two main ways that color is produced in animals: pigments and structures. Cells produce pigments like melanin, which is responsible for black and brown coloration. Meanwhile, structural color comes from the way light bounces off different arrangements of cell structures. Iridescence, the rainbow shimmer that changes depending how light hits an object, is an example of structural colour.

Tropical birds get their colors from a combination of brilliant pigments and structural color.

Researchers  combed through photographs, videos, and even scientific illustrations of 9,409 species of birds— the vast majority of the 10,000-ish living bird species known to science. The researchers kept track of which species have iridescent feathers, and where those birds are found.

The scientists then combined their data on bird coloration and distribution with a pre-existing family tree, based on DNA, showing how all the known bird species are related to each other. They fed the information to a modeling system to extrapolate the origins and spread of iridescence.

Given how modern species are related to each other and where they're found, and overall patterns of how species form and how traits like colors change over time, the modeling software determined the most likely explanation for the bird colors we see today: colorful birds from outside the tropics often came to the region millions of years ago, and then branched out into more and more different species. The model also revealed a surprise about the ancestor of all modern birds.

Part 1

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:59am

Hungry fungi clean up contamination

A growing number of biotech companies are investing in fungal treatments that break down environmental contaminants — from.... Fungi tend to be better than bacteria at tackling large, complex chemicals like the hydrocarbons in many plastics, although this sometimes requires combining different strains of fungi to perform different steps of the process. They can be applied directly to contaminated soil or water, as well as used to break down plastic-based garbage like carpets or mattresses.

https://www.nature.com/articles/s41587-024-02315-y.epdf?sharing_tok...

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:58am

Stolen bacterial genes defeat fungus

Microscopic freshwater animals, just half a millimetre long, have perfected the trick of stealing genes from bacteria, allowing them to fight off infections and survive for millions of years without sex. These unusual creatures, bdelloid rotifers, are all females and 10% of their genes come from foreign organisms. Asexual reproduction should leave them vulnerable to pathogens but some of the ‘borrowed genes’ code for bacterial enzymes known as synthetases, w... — helping the rotifers to defeat fungal infections.

https://www.nature.com/articles/s41467-024-49919-1?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:56am

Fears over viral infection during pregnancy
The 2015-2016 outbreak of the Zika virus caused thousands of birth defects among Brazilians infected during pregnancy; now the country is facing the same fears with the Oropouche virus. Brazil’s health ministry has reported four cases of microcephaly — a type of reduced brain development — in newborns of infected mothers and one fetal death that might be associated with the virus. Oropouche is transmitted by Culicoides paraensis, a tiny midge found across the Americas. Cases of Oropouche fever have surged in Brazil since late 2022. The cases are worrisome and a sign to be alert.

https://www.science.org/content/article/virus-spreading-in-latin-am...

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:26am

This study is the first to show the potential benefits of this treatment in clinical settings beyond melanoma.

The trial included patients with metastatic solid-tumor cancers who were resistant to the anti-PD-1 drug nivolumab. Four had gastric cancer, five had esophageal cancer, and four had hepatocellular carcinoma.

The six FMT donors, who also had gastric cancer, esophageal cancer, or hepatocellular carcinoma, had had a complete or partial response for at least six months after treatment with nivolumab or pembrolizumab. The FMTs were given via colonoscopy after the recipients had received antibiotics to tamp down their own microbiotas.
One of the most surprising results was from a hepatocellular carcinoma patient who initially showed no response to the first FMT and continued to experience cancer progression. However, after switching the donor for the second FMT, the patient exhibited remarkable tumor shrinkage.
The investigators then took a closer look at which bacteria were most likely to affect whether patients benefited from FMT combined with checkpoint inhibitors. In doing so, they identified a novel bacterial strain that helped to improve FMT efficacy, Prevotella merdae Immunoactis.

They also identified two strains that had a detrimental impact on FMT efficacy, Lactobacillus salivarius and Bacteroides plebeius.

They plan to continue studying these and other strains with the goal of developing better ways to boost immunotherapy effectiveness by altering the gut microbiota.
By examining the complex interactions within the microbiome, the researchers hope to identify optimal microbial communities that can be used to enhance cancer treatment outcomes.
This comprehensive approach will help us understand how the microbial ecosystem as a whole contributes to therapeutic success.
Fecal microbiota transplantation improves anti-PD-1 inhibitor efficacy in refractory unresectable or metastatic solid cancers refractory to anti-PD-1 inhibitor, Cell Host & Microbe (2024). DOI: 10.1016/j.chom.2024.06.010. www.cell.com/cell-host-microbe … 1931-3128(24)00228-2

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:24am

Fecal matter transplant helps half of patients with GI cancers overcome immunotherapy resistance

Findings from a small, proof-of-concept clinical trial have suggested that fecal microbiota transplants (FMTs) can boost the effectiveness of immunotherapy in a range of gastrointestinal cancers.

In the study, published July 25 in the journal Cell Host & Microbe, six of 13 patients who had previously shown resistance to immune checkpoint inhibitors benefited from receiving FMTs from donors who had previously responded to treatment. The investigators also identified specific strains of bacteria associated with better or worse responses to FMT and immune checkpoint drugs.

This research highlights the complex interplay between beneficial and detrimental bacteria within the gut microbiota in determining treatment outcomes.

Immune checkpoint inhibitors have revolutionized cancer treatment, but many patients never respond or develop resistance after an initial response. The researchers decided to study FMT in patients receiving immune checkpoint inhibitors because emerging evidence suggests that the gut microbiota plays a crucial role in modulating the immune system and can significantly impact the efficacy of these therapies.

Part 1

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:20am

How epigenetics influence memory formation

When we form a new memory, the brain undergoes physical and functional changes known collectively as a "memory trace." A memory trace represents the specific patterns of activity and structural modifications of neurons that occur when a memory is formed and later recalled.

But how does the brain "decide" which neurons will be involved in a memory trace? Studies have suggested that the inherent excitability of neurons plays a role, but the currently accepted view of learning has neglected to look inside the command center of the neuron itself, its nucleus. In the nucleus, there seems to be another dimension altogether that has gone unexplored: epigenetics.

Inside every cell of a given living organism, the genetic material encoded by the DNA is the same, yet the various cell types that make up the body, like skin cells, kidney cells, or nerve cells each express a different set of genes. Epigenetics is the mechanism of how cells control such gene activity without changing the DNA sequence.

Now, scientists  have explored whether epigenetics might affect the likelihood of neurons to be selected for memory formation. Their research on mice, published in Science, shows that the epigenetic state of a neuron is key to its role in memory encoding.

The researchers  wondered if epigenetic factors could influence the "mnemonic" function of a neuron. A neuron can be epigenetically open when the DNA inside its nucleus is unraveled or relaxed; and closed when the DNA is compact and tight.

They found that it is the open ones that are more likely to be recruited into the "memory trace," the sparse set of neurons in the brain that shows electrical activity when learning something new. Indeed, the neurons that were in a more open chromatin state were also the ones demonstrating higher electrical activity.

The 

scientists then used a virus to deliver epigenetic enzymes to artificially induce openness of the neurons. They found that the corresponding mice learned much better. When the scientists used the opposite approach to close the neurons' DNA, the mice's ability to learn was canceled.

The findings open up new ways to understand learning that encompass the neuron's nucleus, and may even lead one day to medication for improving learning.

Giulia Santoni et al, Chromatin plasticity predetermines neuronal eligibility for memory trace formation, Science (2024). DOI: 10.1126/science.adg9982. www.science.org/doi/10.1126/science.adg9982

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:10am

These recent patients fell ill with the same strain identified in the study as circulating in dairy cows, leading the researchers to suspect that the virus likely originated from dairy farms in the same county.

While the virus does have the ability to infect and replicate in people, the efficiency of those infections is low.

The concern is that potential mutations could arise that could lead adaptation to mammals, spillover into humans and potential efficient transmission in humans in the future. 

It is therefore critical to continue to monitor the virus in affected animals and also in any potential infected humans.

 Diego Diel, Spillover of highly pathogenic avian influenza H5N1 virus to dairy cattle, Nature (2024). DOI: 10.1038/s41586-024-07849-4. www.nature.com/articles/s41586-024-07849-4

Part 2

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:08am

New study confirms mammal-to-mammal avian flu spread

A new study provides evidence that a spillover of avian influenza from birds to dairy cattle across several U.S. states has now led to mammal-to-mammal transmission—between cows and from cows to cats and a raccoon.

This is one of the first times that we are seeing evidence of efficient and sustained mammalian-to-mammalian transmission of highly pathogenic avian influenza H5N1.

Whole genome sequencing of the virus did not reveal any mutations in the virus that would lead to enhanced transmissibility of H5N1 in humans, although the data clearly shows mammal-to-mammal transmission, which is concerning as the virus may adapt in mammals.

So far, 11 human cases have been reported in the U.S., with the first dating back to April 2022, each with mild symptoms: four were linked to cattle farms and seven have been linked to poultry farms, including an outbreak of four cases reported in the last few weeks.

Part1

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 10:20am

The notion that moderate drinking leads to a longer, healthier life goes back decades. As an example, the scientists pointed to the "French paradox"—the idea, popularized in the 1990s, that red wine helps explain why the French enjoy relatively low rates of heart disease, despite a rich, fatty diet. That view of alcohol as an elixir still seems to be "ingrained" in the public imagination, Stockwell noted.

In reality, they said, moderate drinking likely does not extend people's lives—and, in fact, carries some potential health hazards, including increased risks of certain cancers. That's why no major health organization has ever established a risk-free level of alcohol consumption.

"There is simply no completely 'safe' level of drinking," the researchers confirm.

Stockwell, T., et al. Why do only some cohort studies find health benefits from low volume alcohol use? A systematic review and meta-analysis of study characteristics that may bias mortality risk estimates. Journal of Studies on Alcohol and Drugs (2024). DOI: 10.15288/jsad.23-00283. www.jsad.com/doi/10.15288/jsad.23-00283

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