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Comment by Dr. Krishna Kumari Challa on September 4, 2021 at 12:52pm

Fish eyes grown in a petri dish from embryonic stem cells

A research team has demonstrated that complex retinal tissue can be cultured in a Petri dish from embryonic stem cells of bony fish. Until now, stem cells from mammals, including humans, have been used in organoid research. For the first time, researchers have demonstrated that stem cells from medaka and zebrafish can also form highly organized neural structures under controlled laboratory conditions. Among other things, the researchers expect to gain new insights into the basic mechanisms of retinal development.

Organoids are bits of tissue that are grown from stem cells and resemble actual organs. They are used in basic research to gain new information on cell organization and organ development, to investigate the origin of disease, and to develop and test new medications. The major advantage of fish organoids is that they are highly reproducible, unlike organoids from mammalian stem cells. They develop reliably and very quickly and enable a direct comparison with living embryos that in fish grow outside of the womb.

Researchers are  now able to manipulate the molecular and genetic mechanisms of retina  formation.

  Researchers used pluripotent stem cells  from medaka and zebrafish embryos. Such cells have not yet differentiated and can potentially develop into many different cell types. All the cells taken from a single embryo independently aggregated into one large retina within 24 hours. In a matter of a few days, it then formed layers of different cell types that are also found in the fish eye, including photoreceptor cells, bipolar cells, amacrine cells, and ganglion cells. The growth process proved to be incredibly efficient. Hundreds of small retina organoids could be generated within a day. The high throughput allowed the researchers to precisely isolate the conditions in which structures resembling a head with two eyes, including both brain and retina, are formed.

Lucie Zilova et al, Fish primary embryonic pluripotent cells assemble into retinal tissue mirroring in vivo early eye development, eLife (2021). DOI: 10.7554/eLife.66998

https://phys.org/news/2021-09-fish-eyes-grown-petri-dish.html?utm_s...

Comment by Dr. Krishna Kumari Challa on September 4, 2021 at 12:32pm

Unified theory explains how materials transform from solids to liquids

A new study unveils a unified mathematical expression that defines how soft-yet-rigid materials transition from a solid into a liquid flow when they exceed their specific stress threshold.

This study has shown   that these physical states—solid and liquid—can exist together in the same material, and we can explain it using one mathematical expression.

To develop this model, the team performed numerous studies that subjected a variety of different soft materials to stress while measuring the individual solidlike and liquidlike strain responses using a device called a rheometer.

The researchers were able to observe a material's behavior and see a continuous transition between the solid and liquid states and were able to resolve two distinct behaviors that reflect energy dissipation via solid and fluid mechanisms.

Krutarth Kamani et al, Unification of the Rheological Physics of Yield Stress Fluids, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.126.218002

https://phys.org/news/2021-09-theory-materials-solids-liquids.html?...

Comment by Dr. Krishna Kumari Challa on September 4, 2021 at 11:38am

The first cells might have used temperature to divide

A simple mechanism could underlie the growth and self-replication of protocells—putative ancestors of modern living cells—suggests a study publishing September 3 in Biophysical Journal. Protocells are vesicles bounded by a membrane bilayer and are potentially similar to the first unicellular common ancestor (FUCA). On the basis of relatively simple mathematical principles, the proposed model suggests that the main force driving protocell growth and reproduction is the temperature difference that occurs between the inside and outside of the cylindrical protocell as a result of inner chemical activity.

The purpose of this study was to identify the main forces driving cell division. This is important because cancer is characterized by uncontrolled cell division. This is also important to understand the origin of life.

The splitting of a cell to form two daughter cells requires the synchronization of numerous biochemical and mechanical processes involving cytoskeletal structures inside the cell. But in the history of life, such complex structures are a high-tech luxury and must have appeared much later than the ability to split. Protocells must have used a simple splitting mechanism to ensure their reproduction, before the appearance of genes, RNA, enzymes, and all the complex organelles present today, even in the most rudimentary forms of autonomous life.

In the new study, researchers proposed a model based on the idea that the early forms of life were simple vesicles containing a particular network of chemical reactions—a precursor of modern cellular metabolism. The main hypothesis is that molecules composing the membrane bilayer are synthesized inside the protocell through globally exothermic, or energy-releasing, chemical reactions.

The slow increase of the inner temperature forces the hottest molecules to move from the inner leaflet to the outer leaflet of the bilayer. This asymmetric movement makes the outer leaflet grow faster than the inner leaflet. This differential growth increases the mean curvature and amplifies any local shrinking of the protocell until it splits in two. The cut occurs near the hottest zone, around the middle.

The scenario described can be viewed as the ancestor of mitosis. Having no biological archives as old as 4 billion years, we don't know exactly what FUCA contained, but it was probably a vesicle bounded by a lipid bilayer encapsulating some exothermic chemical reactions.

Although purely theoretical, the model could be tested experimentally.

Biophysical Journal, Attal and Schwartz: "Thermally driven fission of protocells" www.cell.com/biophysical-journ … 0006-3495(21)00686-X  , DOI: 10.1016/j.bpj.2021.08.020

https://phys.org/news/2021-09-cells-temperature.html?utm_source=nwl...

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Comment by Dr. Krishna Kumari Challa on September 4, 2021 at 11:31am

Drug cocktail reduces aging-associated disc degeneration

Chronic back pain affects  millions of  adults in the world. Degeneration of the discs that cushion and support vertebrae, a common occurrence of aging, is a major contributor to low back pain. Although a widespread condition, few treatments are available.

With age, every tissue in the body accumulates senescent cells. Senescent cells secrete destructive enzymes and inflammatory proteins that affect nearby healthy cells. Senolytic drugs remove these deteriorating cells, leaving room for new cells to replace them. The idea is that removing senescent cells from a tissue will improve the tissue's function.

New research has shown  that treating mice with a drug cocktail that removes aging cells reduces disc degeneration. The findings, reported in Nature Communications on September 3rd, show how a novel approach to preventing age-related disc degeneration may pave the way for treating chronic back pain.

The findings show that senolytic drugs—ones already approved for use in clinical trials—can mitigate disc degeneration that occurs with aging.

Just because the drugs work in one tissue doesn't mean they will also work in another. Every tissue is different and should be treated differently.

Young and middle-aged mice given the senolytic cocktail showed less disc degeneration and fewer senescent cells by the time they reached an advanced age compared to mice given a placebo.

"Long-term treatment with senolytic drugs Dasatinib and Quercetin ameliorates age-dependent intervertebral disc degeneration in mice." Nature Communications (2021) , DOI: 10.1038/s41467-021-25453-2

https://medicalxpress.com/news/2021-09-drug-cocktail-aging-associat...

Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 2:00pm

How Do Ants Tunnel So Well?

Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 12:13pm

CO₂ stays in the atmosphere for a very, very long time. Many thousands of years. So that greenhouse gas accumulates, and the 'blanket' around the earth thickens. The unique thing about methane is that it halves in the atmosphere in just over 8 years. The other half becomes CO₂. So if you emit 100 kilos of methane today, in 8.5 years there will be 50 kilos left, and after another 8.5 years only 25 kilos, and so on," Vellinga explains. "That CO₂ has gone through what is known as the short carbon cycle: it was converted by grass, corn, etc. into plant material, which the cow converts back into CO₂ and CH₄. And that CH₄ becomes CO₂ again pretty quickly. Nothing to worry about, you might say."

"But be careful not to make the problem too small. Before you know it, it seems as if there is nothing wrong with methane. On the contrary. As long as methane is in the atmosphere, it contributes very strongly to warming. Over the lifetime of methane, this is as much as 80 to 100 times more than CO₂.

But the advantage is that it disappears quickly. Reducing methane emissions can cause the concentration of methane in the atmosphere to drop and therefore even reduce the greenhouse effect. When reducing CO₂, the current greenhouse effect remains the same and only does not increase. So reducing methane is more effective than reducing CO₂. But it has to be done both ways."

https://phys.org/news/2021-09-fact-methane.html?utm_source=nwletter...

Part 2

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Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 12:12pm

How harmful is methane?

Methane contributes to global warming; it is therefore a greenhouse gas. Of all the methane produced in some developed countries, 70% comes from livestock farming. A substantial percentage. But how harmful is it? Because, unlike other greenhouse gasses, methane breaks down relatively quickly in the atmosphere. 

Greenhouse gasses are important. They form a blanket around the earth. Without greenhouse gasses, it would be unbearably cold on earth. The problem with the greenhouses gasses is that we too much of them. The blanket becomes so thick, that the earth's temperature rises. This causes periods of drought and in other places too much precipitation, the polar caps melt, and so on.

there are three greenhouse gasses: carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). Roughly speaking, you can say that all three are created during the breakdown or combustion of organic substances. CO₂ (and NO_x) are mainly created through the combustion of diesel, lignite or gasoline. Not only in transport and traffic, but also in production processes. From the concrete in your house to the staples in your furniture, almost everything in our lives produces CO₂ during its production.

Methane is released during the breakdown of organic substances. For example, in the gastrointestinal tract of animals. Ruminants (cows, goats, sheep) in particular produce a lot of methane. Methane is also 34 times more powerful than carbon dioxide. So, the earth warms up extra fast when there is more methane in the atmosphere. N₂O is created in processes where nitrogen compounds play a role: in manure storage and manure application."

part 1

Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 12:07pm

Decaying forest wood releases 10.9 billion tons of carbon yearly, which will increase with climate change

If you've wandered through a forest, you've probably dodged dead, rotting branches or stumps scattered on the ground. This is "deadwood," and it plays several vital roles in forest ecosystems.

It provides habitat for small mammals, birds, amphibians and insects. And as deadwood decomposes it contributes to the ecosystem's cycle of nutrients, which is important for plant growth.

But there's another important role we have little understanding of on a global scale: the carbon deadwood releases as it decomposes, with part of it going into the soil and part into the atmosphere. Insects, such as termites and wood borers, can accelerate this process.

The world's deadwood currently stores 73 billion tons of carbon. Our new research in Nature has, for the first time, calculated that 10.9 billion tons of this (around 15%) is released into the atmosphere and soil each year—a little more than the world's emissions from burning fossil fuels.

But this amount can change depending on insect activity, and will likely increase under climate change. It's vital deadwood is considered explicitly in all future climate change projections.

Sebastian Seibold et al, The contribution of insects to global forest deadwood decomposition, Nature (2021). DOI: 10.1038/s41586-021-03740-8

https://phys.org/news/2021-09-forest-wood-billion-tons-carbon.html?...

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Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 11:12am

Nano 'camera' made using molecular glue allows real-time monitoring of chemical reactions

Researchers have made a tiny camera, held together with 'molecular glue' that allows them to observe chemical reactions in real time.

The device, made by a team from the University of Cambridge, combines tiny semiconductor nanocrystals called quantum dots and gold nanoparticles using molecular glue called cucurbituril (CB). When added to water with the molecule to be studied, the components self-assemble in seconds into a stable, powerful tool that allows the real-time monitoring of chemical reactions.

The camera harvests light within the semiconductors, inducing electron transfer processes like those that occur in photosynthesis, which can be monitored using incorporated gold nanoparticle sensors and spectroscopic techniques. They were able to use the camera to observe chemical species which had been previously theorized but not directly observed.

The platform could be used to study a wide range of molecules for a variety of potential applications, such as the improvement of photocatalysis and photovoltaics for renewable energy. The results are reported in the journal Nature Nanotechnology.

Földes, T. et al, Nanoparticle surfactants for kinetically arrested photoactive assemblies to track light-induced electron transfer, Nat. Nanotechnol. (2021). DOI: 10.1038/s41565-021-00949-6 , www.nature.com/articles/s41565-021-00949-6

https://phys.org/news/2021-09-nano-camera-molecular-real-time-chemi...

Comment by Dr. Krishna Kumari Challa on September 3, 2021 at 10:57am

Birds and mammals evolve faster if their home is rising

The rise and fall of Earth's land surface over the last three million years shaped the evolution of birds and mammals, a new study has found, with new species evolving at higher rates where the land has risen most.

Researchers at the University of Cambridge have combined reconstructions of the Earth's changing surface elevations over the past three million years with data on climate change over this timeframe, and with bird and mammal species' locations. Their results reveal how species evolved into new ones as land elevation changed—and disentangle the effects of elevation from the effects of climate.

The study found that the effect of elevation increase is greater 

than that of historical climate change, and of present-day elevation and temperature, in driving the formation of new species – 'or speciation'.

In contrast to areas where land elevation is increasing, elevation loss was not found to be an important predictor of where speciation happens. Instead, present-day temperature is a better indicator of speciation in these areas.

The results are published today in the journal Nature Ecology and Evolution.

 Global topographic uplift has elevated speciation in mammals and birds over the last 3 million years, Nature Ecology and Evolution (2021). DOI: 10.1038/s41559-021-01545-6 , www.nature.com/articles/s41559-021-01545-6

https://phys.org/news/2021-09-birds-mammals-evolve-faster-home.html...

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