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Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:34am

Lactobacillus manipulates bile acids to create favorable gut environment

New research  reveals that probiotic Lactobacillus bacteria use enzymes situationally to manipulate bile acids and promote their own survival in the gut. These findings further elucidate the complicated relationship between bile acids and gut bacteria and could eventually enable researchers to design lactobacilli with therapeutic properties, thereby engineering a healthier human gut environment.

Bile acids are key players in digestion and overall gut health. Produced in the liver and released after we eat, these acids not only break down cholesterol and help regulate fat absorption, they also have a huge impact on what types of bacteria colonize the gut.

As bile acids move through the gut, they are initially chemically modified through the addition of an amino acid (frequently glycine or taurine), creating a complex "conjugated" bile acid pool. Some gut bacteria have enzymes, called bile salt hydrolases (BSHs), which can cleave or "deconjugate" these amino acids from the bile acids, allowing other bacteria to further transform the bile acids as they continue through the colon. These transformations affect the bile acids' toxicity, which in turn affects the ability of different bacteria to survive in the gut.

The assumed relationship was that probiotic bacteria like Lactobacillus have BSHs that just deconjugate the bile acid, rendering it less toxic and allowing the bacteria to survive.

The interplay between bile and bacteria has a huge impact on their ability to live, thrive or die in a very competitive environment.

 Matthew H. Foley el al., "Lactobacillus bile salt hydrolase substrate specificity governs bacterial fitness and host colonization," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2017709118

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It was found that bile acid toxicity was not merely dependent upon whether the bile acid was conjugated or deconjugated by a BSH; rather, the relationships were dependent upon the type of bile acid, the bacteria being acted upon, and which BSH was present.

https://phys.org/news/2021-02-lactobacillus-bile-acids-favorable-gu...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:29am

Marine organisms use previously undiscovered receptors to detect, respond to light

Just as plants and animals on land are keenly attuned to the hours of sunlight in the day, life in the oceans follows the rhythms of the day, the seasons and even the moon. A new study finds the biological light switches that make this possible.

Single-celled organisms in the open ocean use a diverse array of genetic tools to detect light, even in tiny amounts, and respond.

If you look in the ocean environment, all these different organisms have this day-night cycle. They are very in tune with each other, even as they get moved around. How do they know when it's day? How do they know when it's night?

By analyzing RNA filtered out of seawater samples collected throughout the day and night, the study identifies four main groups of photoreceptors, many of them new. This genetic activity uses light to trigger changes in the metabolism, growth, cell division, movements and death of marine organisms.

The discovery of these new genetic "light switches" could also aid in the field of optogenetics, in which a cell's function can be controlled with light exposure. Today's optogenetic tools are engineered by humans, but versions from nature might be more sensitive or better detect light of particular wavelengths, the researchers think.

Sacha N. Coesel el al., "Diel transcriptional oscillations of light-sensitive regulatory elements in open-ocean eukaryotic plankton communities," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2011038118

https://phys.org/news/2021-02-marine-previously-undiscovered-recept...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:24am

Part 2

investigated whether sidewinders' skin might also play a role in their unique movement style.

They focused on three species of sidewinders, all of them vipers, in residence at zoos: The sidewinder rattlesnake (Crotalus cerastes), found in the deserts of the Southwestern United States and northern Mexico; and the Saharan horned viper (Cerastes cerastes) and the Saharan sand viper (Cerastes vipera), both from the deserts of north Africa.

Skins shed from the sidewinders were collected and scanned with atomic force microscopy, a technique that provides resolution at the atomic level, on the order of fractions of a nanometer. For comparison, they also scanned snake skins shed from non-sidewinders.

As expected, the microscopy revealed tiny, head-to-tail pointing spikes on the skin of the non-sidewinders. Previous research had identified these micro spikes on a variety of other slithering snakes.

The current study, however, found that the skin of sidewinders is different. The two African sidewinders had micro pits on their bellies and no spikes. The skin of the sidewinder rattlesnake was also studded with tiny pits, along with a few, much smaller, spikes—although far fewer spikes than those of the slithering snakes.

The researchers created a mathematical model to test how these different structures affect frictional interactions with a surface. The model showed that head-to-tail pointing spikes enhance the speed and distance of forward undulation but are detrimental to sidewinding.

The model also showed that the uniform, non-directional structure of the round pits enhanced sidewinding, but was not as efficient as spikes for forward undulation.

The research provides snapshots at different points in time of convergent evolution—when different species independently evolve similar traits as a result of having to adapt to similar environments.

Jennifer M. Rieser el al., "Functional consequences of convergently evolved microscopic skin features on snake locomotion," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2018264118

https://phys.org/news/2021-02-physics-snakeskin-sidewinding.html?ut...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:23am

Physics of snakeskin sheds light on sidewinding

Most snakes get from one place  to another by bending their bodies into S-shapes and slithering forward headfirst. A few species, however—found in the deserts of North America, Africa and the Middle East—have an odder way of getting around. Known as "sidewinders," these snakes lead with their mid-sections instead of their heads, slinking sideways across loose sand.

Scientists took a microscopic look at the skin of sidewinders to see if it plays a role in their unique method of movement. They discovered that sidewinders' bellies are studded with tiny pits and have few, if any, of the tiny spikes found on the bellies of other snakes.

The specialized locomotion of sidewinders evolved independently in different species in different parts of the world, suggesting that sidewinding is a good solution to a problem. Understanding how and why this example of convergent evolution works may allow us to adapt it for our own needs, such as building robots that can move in challenging environments.

This research bring together the physics of soft matter—flowable materials like sand—and organismal biology. The study shows how animals' surfaces interact with the flowable materials in their environments to get around. Insights from the research may lead to improvements in human technology.

Most snakes tend to keep their bellies largely in contact with the ground as they slide forward, bending their bodies from their heads to their tails. A sidewinder, however, lifts its midsection off the ground, shifting it in a sideways direction.

Previous studies have hypothesized that sidewinding may allow a snake to move better on sandy slopes.

Part 1

Comment by Dr. Krishna Kumari Challa on February 1, 2021 at 10:55am

Using science to explain the mysterious Dyatlov Pass Incident

Comment by Dr. Krishna Kumari Challa on February 1, 2021 at 10:04am

Mouse study: Gabapentin prevents harmful structural changes in spin...

Research led by The Ohio State University Wexner Medical Center and College of Medicine found that the widely prescribed pain-relief drug gabapentin can prevent harmful structural changes in the injured spinal cords of mice, and also block cardiovascular changes and immune suppression caused by spinal cord injury.

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Study provides insight into how the brain may have evolved

Researchers from The University of Western Australia have uncovered evidence of an important genetic step in the evolution of the brain. The finding highlights how genetic events that took place in our fish-like ancestors play crucial roles in human brain biology today.

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How vitamins, steroids and potential antivirals might affect SARS-C...

Evidence is emerging that vitamin D—and possibly vitamins K and A—might help combat COVID-19. A new study from the University of Bristol published in the journal of the German Chemical Society Angewandte Chemie has shown how they—and other antiviral drugs—might work. The research indicates that these dietary supplements and compounds could bind to the viral spike protein and so might reduce SARS-CoV-2 infectivity. In contrast, cholesterol may increase infectivity, which could explain why having high cholesterol is considered a risk factor for serious disease.

Comment by Dr. Krishna Kumari Challa on February 1, 2021 at 10:02am

Geological phenomenon widening the Atlantic Ocean

An upsurge of matter from deep beneath the Earth's crust could be pushing the continents of North and South America further apart from Europe and Africa, new research has found.

The plates attached to the Americas are moving apart from those attached to Europe and Africa by four centimetres per year. In between these continents lies the Mid-Atlantic Ridge, a site where new plates are formed and a dividing line between plates moving to the west and those moving to the east; beneath this ridge, material rises to replace the space left by the plates as they move apart.

Now a team of  seismologists  have found evidence of an upwelling in the mantle—the material between the Earth's crust and its core—from depths of more than 600 kilometres beneath the Mid Atlantic ridge, which could be pushing the plates from below, causing the continents to move further apart. Upwellings beneath ridges are typically thought to originate from much shallower depths of around 60 km.

The findings, published in the journal Nature provide a greater understanding of plate tectonics which causes many natural disasters around the world, including earthquakes, tsunamis and volcanic eruptions.

A thin mantle transition zone beneath the equatorial Mid-Atlantic Ridge, Nature (2021). DOI: 10.1038/s41586-020-03139-x , www.nature.com/articles/s41586-020-03139-x

https://phys.org/news/2021-01-geological-phenomenon-widening-atlant...

Comment by Dr. Krishna Kumari Challa on January 31, 2021 at 1:11pm

The physics behind tumor growth

Researchers at Duke University have developed a predictive theory for tumor growth that approaches the subject from a new point of view. Rather than focusing on the biological mechanisms of cellular growth, the researchers instead use thermodynamics and the physical space the tumor is expanding into to predict its evolution from a single cell to a complex cancerous mass.

The results appeared Jan. 15 in the journal Biosystems.

The new work is based on the constructal law, which Bejan penned in 1996, that states that for a system to survive, it must evolve to increase its access to flow. For example, the human vascular system has evolved to provide blood flow through a network of a few large arteries and many small capillaries. River systems, tree branches and modern highway and road networks all reflect the same forces at work.

In the paper researchers demonstrate how a tumor’s growth and internal reorganization as it grows are directly tied to its need to create greater access to flowing nutrients as well as conduits for removing refuse. They use these insights to predict the growth of cell clusters as a function of structure, and also to predict the critical cluster sizes that mark the transitions from one distinct configuration to the next.

To validate their theory, the researchers compared their predictions with the measurements of several independent studies of cancerous and non-cancerous tumor growth patterns. The results show that their work provides a unifying perspective on the growth of cell clusters on the smallest scales as well as the large-scale dynamics of proliferating cells as described in phenomenological models.

As the tumor grows, the flow systems get large enough to create visible currents through the vascularization of the tumor. The new theory reveals the physics behind these sorts of dramatic transitions and predict when they should happen.

https://pratt.duke.edu/about/news/physics-tumor-growth

“Cell and Extracellular Matrix Growth Theory and its Implications for Tumorigenesis,” T.J. Sauer, E. Samei, A. Bejan. Biosystems, Jan. 15, 2021. DOI: 10.1016/j.biosystems.2020.104331

Comment by Dr. Krishna Kumari Challa on January 31, 2021 at 1:07pm

Wireless linkage of brains may soon go to human testing

Comment by Dr. Krishna Kumari Challa on January 31, 2021 at 12:26pm

A protein that can melt tumors discovered at Vanderbilt
 For the second time, cancer researchers at Vanderbilt have discovered a protein that when genetically manipulated to impede it from interacting with a gene responsible for cancer genesis effectively melts tumors in days. The article, MYC regulates ribosome biogenesis and mitochondrial gene expression programs through interaction with Host Cell Factor-1, was published in the journal eLIFE on Jan. 8.

https://researchnews.cc/news/4842/A-protein-that-can-melt-tumors-di...

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