Comment

Comment by Dr. Krishna Kumari Challa 47 minutes ago

Scientists control bacterial mutations to preserve antibiotic effectiveness

Scientists have discovered a way to control mutation rates in bacteria, paving the way for new strategies to combat antibiotic resistance.

Antibiotics are given to kill bad bacteria; however, with just one mutation a bacteria can evolve to become resistant to that antibiotic, making common infections potentially fatal.

The new research, published recently in the journal PLOS Biology, used high-performance computing to simulate more than 8,000 years of bacterial evolution, allowing scientists to predict mechanisms that control mutation rates.

They then made more than 15,000 cultures of E. coli in lab conditions to test their predictions—that's so many that if you lined up all of the bacteria in this study, they would stretch 860,000 km, or wrap around the Earth more than 20 times.

The tests revealed that bacteria living in a lowly populated community are more prone to developing antibiotic resistance due to a naturally occurring DNA-damaging chemical, peroxide. In crowded environments, where cells are more densely packed, bacteria work collectively to detoxify peroxide, reducing the likelihood of mutations that lead to antibiotic resistance.

The finding could help develop "anti-evolution drugs" to preserve antibiotic effectiveness by limiting the mutation rates in bacteria.

By understanding the environmental conditions that influence mutation rates, we can develop strategies to safeguard antibiotic effectiveness. This new study shows that bacterial mutation rates are not fixed and can be manipulated by altering their surroundings, which is vital on our journey to combat antibiotic resistance.

Peroxide, a chemical found in many environments, is key to this process. When E. coli populations become denser, they work together to lower peroxide levels, protecting their DNA from damage and reducing mutation rates. The study showed that genetically modified E. coli that is unable to break down peroxide had the same mutation rates, no matter the population size. However, when helper cells that could break down peroxide were added, the mutation rate in these genetically modified E. coli decreased.

Rowan Green et al, Collective peroxide detoxification determines microbial mutation rate plasticity in E. coli, PLOS Biology (2024). DOI: 10.1371/journal.pbio.3002711

Comment by Dr. Krishna Kumari Challa 54 minutes ago

New aerospace and building materials could repair themselves thanks to fungi and bacteria

Researchers are using biological matter to create unique new materials that can adapt to their environment and repair themselves.

Researchers are developing what they call "living materials," for use in the aerospace and transportation sectors. These living materials are, precisely as they sound, literally alive. They contain microorganisms such as fungi and bacteria, which give them the capacity to sustain their integrity and self-healing.

The goal is to make engineered structures that can behave like living organisms, able to sense and adapt to mechanical stresses.

The material they are developing is a composite that combines living fungi cells and wood. It consists of a hydrogel and mycelium, a root-like structure of a fungus that normally lives underground.

They chose to work with fungi because fungus is a really robust organism, it is tolerant to harsh conditions and is relatively easy to cultivate. 

Moreover, fungal cells have a great ability to connect. Mycelium can grow a vast sensing network that allows it to send signals throughout the organism. That means the scientists can distribute only a few cells throughout the material, and these cells will reconnect and form a sensing network.

Biological materials could help to improve the performance and durability of critical structures used in areas like aerospace and transportation.

These materials are very lightweight and more sustainable than currently used materials. 

Sources: 

• AM-IMATE
• ARCHISKIN
• EU research and innovation for chemicals and advanced materials

Comment by Dr. Krishna Kumari Challa 1 hour ago

Ice 0: Researchers discover a new mechanism for ice formation

Ice is far more complicated than most of us realize, with over 20 different varieties known to science, forming under various combinations of pressure and temperature. The kind we use to chill our drinks is known as ice I, and it's one of the few forms of ice that exist naturally on Earth.

Researchers have recently discovered another type of ice: ice 0, an unusual form of ice that can seed the formation of ice crystals in supercooled water.

The formation of ice near the surface of liquid water can start from tiny crystal precursors with a structure similar to a rare type of ice, known as ice 0.

In a study published in Nature Communications, researchers showed that these ice 0-like structures can cause a water droplet to freeze near its surface rather than at its core. This discovery resolves a longstanding puzzle and could help redefine our understanding of how ice forms.

Crystallization of ice, known as ice nucleation, usually happens heterogeneously, or in other words, at a solid surface. This is normally expected to happen at the surface of the water's container, where liquid meets solid.

However, this new research shows that ice crystallization can also occur just below the water's surface, where it meets the air. Here, the ice nucleates around small precursors with the same characteristic ring-shaped structure as ice 0.

Simulations have shown that a water droplet is more likely to crystallize near the free surface under isothermal conditions. This resolves a longstanding debate about whether crystallization occurs more readily on the surface or internally.

Ice 0 precursors have a structure very similar to supercooled water, allowing water molecules to crystallize more readily from it, without needing to directly form themselves into the structure of regular ice.

The tiny ice 0 precursors are formed spontaneously, as a result of negative pressure effects caused by the surface tension of water. Once crystallization begins from these precursors, structures similar to ice 0 quickly rearrange themselves into the more familiar ice I.

Surface-induced water crystallization driven by precursors formed in negative pressure regions, Nature Communications (2024). DOI: 10.1038/s41467-024-50188-1

Comment by Dr. Krishna Kumari Challa 1 hour ago

Birds are a specialized group of dinosaurs— the earliest known bird, Archaeopteryx, lived 140 million years ago. A sub-group of birds called Neornithes evolved 80 million years ago, and this group became the only birds (and dinosaurs) to survive the mass extinction 66 million years ago.
All modern birds are members of Neornithes.The model produced by researchers now suggests that the common ancestor of all Neornithes, 80 million years ago, had iridescent feathers that still glitter across the bird family tree.
Researchers found fossil evidence of iridescent birds and other feathered dinosaurs before, by examining fossil feathers and the preserved pigment-producing structures in those feathers. So we know that iridescent feathers existed back in the Cretaceous—those fossils help support the idea from this new model that the ancestor of all modern birds was iridescent too.
The discovery that the first Neornithes was likely iridescent could have important implications for paleontology.

Transitions between colour mechanisms affect speciation dynamics and range distributions of birds, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02487-5

Part 2

Comment by Dr. Krishna Kumari Challa 1 hour ago

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 22 hours ago

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 22 hours ago

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 22 hours ago

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 23 hours ago

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 23 hours ago

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.

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