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Comment by Dr. Krishna Kumari Challa on May 13, 2022 at 12:00pm

Later researchers sequenced the RNA transcriptome of the optic gland at different stages of their maternal decline. RNA carries instructions from DNA about how to produce proteins, so sequencing it is a good way to understand the activity of genes and what's going on inside cells at a given time. As the animals began to fast and decline, there were higher levels of activity in genes that metabolize cholesterol and produce steroids, the first time the optic gland had been linked to something other than reproduction.

In the new paper, published this week in Current Biology, scientists took their studies a step further and analyzed the chemicals produced by the maternal octopus optic gland, specifically cholesterol. 

The new research shows that the maternal optic gland undergoes dramatic changes to produce more pregnenolone and progesterone, maternal cholestanoids, and 7-DHC during the stages of decline. While the pregnancy hormones are to be expected, this is the first time anything like the components for bile acids or cholesterol have been linked to the maternal octopus death spiral.

Some of these same pathways are used for producing cholesterol in mice and other mammals as well. 

Elevated levels of 7-DHC are toxic in humans; It's the hallmark of a genetic disorder called Smith-Lemli-Opitz syndrome (SLOS), which is caused by a mutation in the enzyme that converts 7-DHC to cholesterol. Children with the disorder suffer from severe developmental and behavioral consequences, including repetitive self-injury reminiscent of octopus end-of-life behaviors.

Z. Yan Wang, Steroid hormones of the octopus self-destruct system, Current Biology (2022). DOI: 10.1016/j.cub.2022.04.043. www.cell.com/current-biology/f … 0960-9822(22)00661-3

Part 2

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Comment by Dr. Krishna Kumari Challa on May 13, 2022 at 11:55am

How cholesterol plays a part in the life cycle process and death

For all their uncanny intelligence and seemingly supernatural abilities to change color and regenerate limbs, octopuses often suffer a tragic death. After a mother octopus lays a clutch of eggs, she quits eating and wastes away; by the time the eggs hatch, she is dead. Some females in captivity even seem to speed up this process intentionally, mutilating themselves and twisting their arms into a tangled mess.

The source of this bizarre maternal behavior seems to be the optic gland, an organ similar to the pituitary  in mammals. For years, just how this gland triggered the gruesome death spiral was unclear, but a new study by researchers 

shows that the optic gland in maternal octopuses undergoes a massive shift in cholesterol metabolism, resulting in dramatic changes in the steroid hormones produced. Alterations in cholesterol metabolism in other animals, including humans, can have serious consequences on longevity and behavior, and the study's authors believe this reveals important similarities in the functions of these steroids across the animal kingdom, in soft-bodied cephalopods and vertebrates alike.

Cholesterol is important from a dietary perspective, and within different signaling systems in the body too. It's involved in everything from the flexibility of cell membranes to production of stress hormones, but it was a big surprise to see it play a part in this life cycle process as well.

In 1977, Brandeis University psychologist Jerome Wodinsky showed that if he removed the optic gland from Caribbean two-spot octopus (Octopus hummelincki) mothers, they abandoned their clutch of eggs, resumed feeding, and lived for months longer. At the time, cephalopod biologists concluded that the optic gland must secrete some kind of "self-destruct" hormone, but just what it was and how it worked was unclear.

Part 1

Comment by Dr. Krishna Kumari Challa on May 13, 2022 at 11:03am

What it Takes to Image a Black Hole

Comment by Dr. Krishna Kumari Challa on May 12, 2022 at 1:32pm

Exoskeleton device helps stroke victims regain hand function

Simulation Suggests Some Volcanoes Might Warm Climate, Destroy Ozone Layer

Comment by Dr. Krishna Kumari Challa on May 12, 2022 at 1:28pm

Scientists transform beating heart stem cells into brain cells

By turning off a single gene,  researchers  caused stem cells already becoming heart cells to change course and become future brain cells. And that could help scientists understand how specific genes affect the development of your body and the role they play in developmental diseases, potentially leading to new therapies.

Previously, it’s been thought that the paths that cells take towards becoming a heart cell or a nerve cell are very rigid. This study is showing that this process is actually much more fluid.

Stem cells are kind of a blank slate. They’re “pluripotent,” meaning that they can transform into any type of cell in the body. There are a series of steps involved in this transformation process, called canalization. Until now, it was thought that once stem cells start undergoing canalization, they can’t change course to become other, different cell types.

Scientists now used CRISPR genome-editing approaches to turn off the Brm gene in mouse stem cells undergoing canalization into heart cells. This resulted in the mouse cells lacking a protein called Brahma.

Turning off Brm prevented stem cells from becoming beating heart cells. Additionally, they had switched from being heart precursors to become precursors for brain cells.

This study was the first to explore the effect of Brahma on cardiac differentiation

1. Nan Cao, Yu Huang, Jiashun Zheng, C. Ian Spencer, Yu Zhang, Ji-Dong Fu, Baoming Nie, Min Xie, Mingliang Zhang, Haixia Wang, Tianhua Ma, Tao Xu, Guilai Shi, Deepak Srivastava, Sheng Ding. Conversion of human fibroblasts into functional cardiomyocytes by small molecules. Science, 2016 DOI: 10.1126/science.aaf1502
2. Mingliang Zhang , Yuan-Hung Lin , Yujiao Jennifer Sun , Saiyong Zhu10 , Jiashun Zheng , Kai Liu , Nan Cao , Ke Li , Yadong Huang , Sheng Ding. Pharmacological Reprogramming of Fibroblasts into Neural Stem Cells by Signaling-Directed Transcriptional Activation. Cell Stem Cell, 2016 DOI: 10.1016/j.stem.2016.03.020

Comment by Dr. Krishna Kumari Challa on May 12, 2022 at 10:52am

For the first time, researchers have observed an X-ray explosion on...

When stars like our sun use up all their fuel, they shrink to form white dwarfs. Sometimes such dead stars flare back to life in a super-hot explosion and produce a fireball of X-ray radiation. A research team  has now been able to observe such an explosion of X-ray light for the very first time.

--

Scientists solve problem of industrial waste from sugarcane process... Scientists have discovered how to significantly improve the sustainability of the sugarcane industry by turning a major by-product into a valuable chemical used in food, medicines and cosmetics. -- A nontoxic glue for plywood—from glucose, citric acid The go-to materials for building home furniture, décor and floors are composite wood products that come in large sheets. But the glues and resins holding together particleboard, fiberboard and plywood usually contain formaldehyde and could release this probable carcinogen into the air. To develop a nontoxic adhesive, researchers reporting in ACS Applied Materials & Interfaces have combined glucose and citric acid—sugar and an orange juice ingredient—into a strong, water-resistant wood glue for plywood.

Comment by Dr. Krishna Kumari Challa on May 12, 2022 at 10:07am

Magnetism is a collective phenomenon in which the electrons in a material all spin in the same direction. An everyday example is the ferromagnet, which owes its magnetic properties to the alignment of spins. Neighboring electrons can also spin in opposite directions. In this case, the spins still have well-defined directions but there is no magnetization. Frustrated magnets are frustrated because the neighboring electrons try to orient their spins in opposing directions, and when they find themselves in a triangular lattice, they can no longer settle on a common, stable arrangement. The result: a frustrated magnet.

E. M. Smith et al, Case for a U(1)π Quantum Spin Liquid Ground State in the Dipole-Octupole Pyrochlore Ce₂Zr₂O₇, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.021015

Part 2

Comment by Dr. Krishna Kumari Challa on May 12, 2022 at 10:07am

Unusual quantum state of matter observed for the first time

It's not every day that someone comes across a new state of matter in quantum physics. Yet this is exactly what an international team of physicists has done recently. 

In a recent article published in the scientific journal Physical Review X, the researchers document a "quantum spin liquid ground state" in a magnetic material created in  lab: Ce₂Zr₂O₇, a compound composed of cerium, zirconium and oxygen.

In quantum physics, spin is an internal property of electrons linked to their rotation. It is spin that gives the material in a magnet its magnetic properties.

In some materials, spin results in a disorganized structure similar to that of molecules in a liquid, hence the expression "spin liquid."

In general, a material becomes more disorganized as its temperature rises. This is the case, for example, when water turns into steam. But the principal characteristic of spin liquids is that they remain disorganized even when cooled to as low as absolute zero (–273°C).

Spin liquids remain disorganized because the direction of spin continues to fluctuate as the material is cooled instead of stabilizing in a solid state, as it does in a conventional magnet, in which all the spins are aligned.

Imagine an electron as a tiny compass that points either up or down. In conventional magnets, the electron spins are all oriented in the same direction, up or down, creating what is known as a "ferromagnetic phase." This is what keeps photos and notes pinned to your fridge.

But in quantum spin liquids, the electrons are positioned in a triangular lattice and form a "ménage à trois" characterized by intense turbulence that interferes with their order. The result is an entangled wave function and no magnetic order.

When a third electron is added, the electron spins cannot align because the two neighboring electrons must always have opposing spins, creating what we call magnetic frustration.

This generates excitations that maintain the disorder of spins and therefore the liquid state, even at very low temperatures."

So how did they add a third electron and cause such frustration?

Enter the frustrated magnet Ce₂Zr₂O₇ created by physicists in a  lab. 

Ce₂Zr₂O₇ is a cerium-based material with magnetic properties. The existence of this compound was known. This new breakthrough was creating it in a uniquely pure form. They used samples melted in an optical furnace to produce a near-perfect triangular arrangement of atoms and then checked the quantum state.

It was this near-perfect triangle that enabled this team  to create magnetic frustration in Ce₂Zr₂O₇.

Their  measurements showed an overlapping particle function—therefore no Bragg peaks—a clear sign of the absence of classical magnetic order. They also observed a distribution of spins with continuously fluctuating directions, which is characteristic of spin liquids and magnetic frustration. This indicates that the material they created behaves like a true spin liquid at low temperatures.

After corroborating these observations with computer simulations, the team concluded that they were indeed witnessing a never-before-seen quantum state.

Part 1

Comment by Dr. Krishna Kumari Challa on May 11, 2022 at 8:46am

Distantly related mushrooms gained the ability to make toxin via horizontal gene transfer
A team of researchers affiliated with several institutions in China and the U.S. has found evidence that suggests three distantly related types of mushrooms gained their ability to produce a dangerous toxin via horizontal gene transfer sometime in their past. In their paper published in Proceedings of the National Academy of Sciences, the group describes their genetic analysis of multiple species of mushrooms to determine which genes in three particular species were responsible for producing the same toxin and what it showed them about its origins.

Scientists have known for some time that the three mushrooms—the deadly dapperling, the destroying angel and the funeral bell—are not only toxic, but also have an identical toxin. Some scientists assumed they must have a common ancestor, but the researchers in this new effort suspected something else was afoot because the three species are so distantly related. To get to the bottom of the matter, they obtained samples of the three mushrooms along with samples from 12 others.

To find out which part of their genome was responsible for making the toxins, the researchers sequenced all of their samples. They found two genes that were responsible for creating the toxins and were identical in all three species. A closer look at the genes showed that they were, indeed, distantly related, but it also showed that the genes responsible for producing the toxins were not passed down from a common ancestor. That left just one other possibility—sometime in their past, all three had received a horizontal gene transfer from another, possibly extinct, mushroom.

A horizontal gene transfer occurs when a third party, such as a bacterium, absorbs some of the genome of a host it is infecting and then passes those cells into another host that it infects. The researchers note that horizontal gene transfer is common with bacteria. In many cases, they steal bits of host DNA, add it to their own, and then pass it on to their offspring. Those offspring can then add the new DNA to cells they infect in another host.

Hong Luo et al, Genes and evolutionary fates of the amanitin biosynthesis pathway in poisonous mushrooms, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2201113119

Comment by Dr. Krishna Kumari Challa on May 11, 2022 at 8:41am

Only 3% of potential bacterial drug sources known
The emergence of antibiotic-resistant pathogens and the increasing difficulty in developing new drugs has contributed to global challenges in combating infectious diseases. An extensive bioinformatics survey of around 170,000 bacterial genomes indicates that only three percent of the genomic potential for microbial natural products—chemically diverse bacterial metabolites that form the basis of antibiotic drugs—have been discovered so far. Co-led by Prof Nadine Ziemert of the German Center for Infection Research (DZIF), the survey identified several bacterial genera as producers of highly diverse natural products that could help to overcome the bottleneck in drug development.

Bacterial producers of natural products as sources of drugs such as antibiotics have been studied for decades. However, the rate of new drug discovery has stagnated in recent years. There is uncertainty on how much chemical diversity exists in nature and how many new compounds can still be discovered. Additionally, assumptions that a large portion of natural product-producers and respective biosynthetic pathways have been discovered already have not been investigated.

To understand the true potential of useful biosynthetic pathways and natural products in the bacterial world, an international team of researchers from Germany, the Netherlands and the United States surveyed a large amount of genomic data—around 170,000 bacterial genomes and several thousands of so-called Metagenome Assembled Genomes representing individual microbial taxa from diverse environments. Using a genome mining strategy, the team identified so-called Biosynthetic Gene Clusters (BGCs)—clusters of genes in bacterial genomes that jointly encode the biosynthesis pathways of natural products. Grouping the BGCs into gene cluster families according to similarity, the researchers developed tools that allow the study of the biosynthetic diversity represented in the bacterial genome database.

This bioinformatics genome mining approach reveals that only three percent or even less of the genomic potential for the production of natural products has been discovered so far.

Based on the mined data, the researchers identified bacterial taxa that showed high biosynthetic potential, among them multiple unexplored taxonomic groups. 

Athina Gavriilidou et al, Compendium of specialized metabolite biosynthetic diversity encoded in bacterial genomes, Nature Microbiology (2022). DOI: 10.1038/s41564-022-01110-2

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