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Comment by Dr. Krishna Kumari Challa on October 21, 2021 at 10:56am

A breakdown in communication -- mitochondria of diabetic patients can’t keep time

Almost all cells regulate their biological processes over a 24-hour period, otherwise called a cell’s circadian rhythm. To do so, cells use a biological clock that cycles different genes on and off throughout the day and night. Scientists already know that our metabolic health can suffer when our biological clock breaks down, due to shift work or sleep disorders, for example. However, it’s unclear how exactly the biological clock of people with type 2 diabetes differs from healthy people.

Now a team of international scientists has shown that the skeletal muscle in people with type 2 diabetes has a different circadian rhythm. They argue that this might arise because of a communication breakdown between a cell’s time keeping molecules and mitochondria, which produce chemical energy for cells.

In the study, which was published in Science Advances, the scientists first obtained skeletal muscle cells from people with type 2 diabetes and measured which genes showed cycling behavior over two days and compared them with cells from similar healthy people. They discovered that cells from people with type 2 diabetes had fewer, and some different, cycling genes.

They carried out further experiments using data generated from clinical tests in people with type 2 diabetes and mice, as well as cell-based experiments. These experiments demonstrated that mitochondria communicate with the molecules that keep time in our cells, and that this communication is disrupted in people with type 2 diabetes.

Diabetes treatments may be more effective if timed to the body clock

Some of the most widely used pharmacological treatments for type 2 diabetes affect mitochondria, meaning that they may work differently depending on the time of day they are taken. As a result, these findings highlight the importance of considering cellular rhythms when prescribing treatments for type 2 diabetes.

“Exercise and diet are regularly used treatment interventions for people with type 2 diabetes, and both of these treatments can affect the time-keeping molecules and mitochondria.

Given that disrupted sleeping patterns are known to be associated with an increased risk of developing type 2 diabetes, these findings provide evidence of how these disruptions may link to the molecular biology within cells.

https://www.science.org/doi/10.1126/sciadv.abi9654

https://www.eurekalert.org/news-releases/932152

Comment by Dr. Krishna Kumari Challa on October 21, 2021 at 10:29am

Researchers have known how small molecules penetrate cell membranes, typically by binding to the membrane and then diffusing through it. But they knew that proteins do not have that ability because they are too big. Until now, the most popular hypothesis was that proteins pass through small holes, known as pores, in the membrane. But previous work did not support that hypothesis.

While working on other projects, researchers noticed that some fragments of proteins, known as peptides, cross membranes by pushing against them. The peptides deformed the membrane into small circular buds. The buds then detach as small bubbles, known as vesicles, which eventually "pop," allowing the peptides to be released inside the cell. The team subsequently observed that two structurally different bacterial toxins also employed this same mechanism. This discovery led them to conclude that this budding-and-collapse mechanism is a common mechanism employed by many large biomolecules.

The team witnessed the budding-and-collapse in live cells through confocal microscopy, an imaging technique that allowed them to focus in on what was happening inside the cells, and on the cell membranes, with these specific proteins.

Researchers say the discovery could potentially open the door for new drug therapies that use this finding to manipulate the ways drugs enter a cell.

Ashweta Sahni et al, Bacterial Toxins Escape the Endosome by Inducing Vesicle Budding and Collapse, ACS Chemical Biology (2021). DOI: 10.1021/acschembio.1c00540

https://phys.org/news/2021-10-magic-proteins-cell-walls.html?utm_so...

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Comment by Dr. Krishna Kumari Challa on October 21, 2021 at 10:26am

How certain proteins pass through cell walls

All these days scientists have wondered how large molecules such as proteins pass through cell walls, also known as plasma membranes, without leaving a trace. That ability is part of what makes certain drugs—including some cancer treatments and the COVID-19 vaccine—work. And it is also how bacterial toxins enter human cells and wreak havoc.

One such example is diphtheria toxin, which is produced by Corynebacterium diphtheriae and causes diphtheria, a serious and potentially fatal bacterial infection of the nose and throat. But the mechanics of how these proteins enter human cells were a scientific mystery till now.

A recent study, published in the journal ACS Chemical Biology, answers that mystery. The study identified the ways in which proteins cross a cell membrane, a finding that could create a scientific foundation for better ways of delivering drugs into cells in the future, or for treating illnesses caused by bacterial toxins.

It is almost like a magic trick, the way the membrane encapsulates these toxins.

Part 1

Comment by Dr. Krishna Kumari Challa on October 21, 2021 at 9:53am

Researchers make hardened wooden knives that slice through steak

The sharpest knives available are made of either steel or ceramic, both of which are man-made materials that must be forged in furnaces under extreme temperatures. Now, researchers have developed a potentially more sustainable way to make sharp knives: using hardened wood. The method, presented October 20th in the journal Matter, makes wood 23 times harder, and a knife made from the material is nearly three times sharper than a stainless-steel dinner table knife. The knife cuts through a medium-well done steak easily, with similar performance to a dinner table knife.  This hardened wood  knife can be washed and reused, making it a promising alternative to steel, ceramic, and disposable plastic knives.

Teng Li, Hardened Wood as a Renewable Alternative to Steel and Plastic, Matter (2021). DOI: 10.1016/j.matt.2021.09.020. www.cell.com/matter/fulltext/S2590-2385(21)00465-3

https://phys.org/news/2021-10-hardened-wooden-knives-slice-steak.ht...

Comment by Dr. Krishna Kumari Challa on October 20, 2021 at 10:23am

Bacteriophages: an interesting alternative to antibiotics

Bacteriophages are viruses that kill specific types of bacteria.

Phages' ability to selectively kill bacteria also has medical doctors excited. Natural and engineered phages have been successfully used to treat bacterial infections that do not respond to antibiotics. This process, known as phage therapy, could help fight antibiotic resistance.

Comment by Dr. Krishna Kumari Challa on October 20, 2021 at 9:08am

More than 99.9% of studies agree: Humans caused climate change

More than 99.9% of peer-reviewed scientific papers agree that climate change is mainly caused by humans, according to a new survey of 88,125 climate-related studies.

he research updates a similar 2013 paper revealing that 97% of studies published between 1991 and 2012 supported the idea that human activities are altering Earth's climate. The current survey examines the literature published from 2012 to November 2020 to explore whether the consensus has changed.

We now are virtually certain that the consensus is well over 99% now and that it's pretty much case closed for any meaningful public conversation about the reality of human-caused climate change.

It's critical to acknowledge the principal role of greenhouse gas emissions so that we can rapidly mobilize new solutions, since we are already witnessing in real time the devastating impacts of climate related disasters on businesses, people and the economy.

Greater than 99% Consensus on Human Caused Climate Change in the Peer-Reviewed Scientific Literature, Environmental Research Letters (2021). DOI: 10.1088/1748-9326/ac2966, https://iopscience.iop.org/article/10.1088/1748-9326/ac2966

https://phys.org/news/2021-10-humans-climate.html?utm_source=nwlett...

Comment by Dr. Krishna Kumari Challa on October 20, 2021 at 9:03am

New understanding on how brain cells talk

Researchers have discovered that reversing the modification of molecular messages at synapses in the human brain, may contribute to reversible mental health conditions such as anxiety, and memory diseases such as dementia.

The findings are a major step in our understanding how brain cells  communicate, and could help to identify new treatments for neurological and psychiatric conditions.

Nerve cells in the human brain talk to one another at sites called synapses, where molecules are released to signal to the next cell. When people learn or remember things, this signaling is strengthened. When communication between synapses goes wrong, circuits become broken. As more circuits are lost, this changes how people can think and perform everyday tasks. This is seen in cognitive disorders, such as forms of dementia and some mental health conditions.

The function of nerve cells and synapses depends on proteins that are made using information encoded in genetic material called RNA. It is thought that RNAs are located exactly where and when they are needed for synaptic signaling because some kind of synaptic 'tag' labels the correct active synapse. Scientists have recently learnt that RNA can have a methyl group/molecule added to one of the RNA bases which 'marks' the RNA message. Such adding of methyl groups can influence proteins binding to DNA or RNA and consequently stop proteins being produced.

This new study shows that RNA marking can be reversed at synapses and hence may act as a 'synaptic tag'. The findings suggest, that if disrupted, this could cause synapses and nerve cells to malfunction by influencing the formation of toxic protein clumps.

The researchers used advanced microscopy to examine changes in marked RNAs in time and location at synapses, and a sequencing technique to characterize 'marked' RNAs in brain tissue from the hippocampus, a region of the brain very important for memory formation.

 are able to gain a new understanding of the genomic mechanisms which regulate how nerve cells communicate at synapses. These genomic mechanisms involve methyl groups being put on RNA messages and importantly taken off when a synapse is active. The implications are very important for normal brain function but also for reversible psychiatric mental conditions such as anxiety and addiction disorders and early-stage neurodegenerative diseases such as dementias.

Braulio Martinez De La Cruz et al, Modifying the m6A brain methylome by ALKBH5-mediated demethylation: a new contender for synaptic tagging, Molecular Psychiatry (2021). DOI: 10.1038/s41380-021-01282-z

https://medicalxpress.com/news/2021-10-scientists-gain-brain-cells....

Comment by Dr. Krishna Kumari Challa on October 19, 2021 at 10:46am

Researchers  came up with a plan for settling the debate once and for all.

 The international team of researchers then placed their bet that paleomagnetic data from limestones created in the Cretaceous (between ~145.5 and 65.5 million years ago) located in Italy would provide a definitive test. The magnetism of the younger rocks in the same area was studied nearly 50 years ago, and indirectly led to the discovery of the asteroid impact that killed the dinosaurs. These Italian sedimentary rocks turn out to be special and very reliable because the magnetic minerals are actually fossils of bacteria that formed chains of the mineral magnetite.

To test their hypothesis about true polar wander, paleomagnetic data with lots of redundancy are required to track the wander of the ancient location of Earth's spin axis. Prior studies, especially some claiming that true polar wander does not occur, have failed to explore enough data points according to the team.

That is one reason why it is so refreshing to see this study with its abundant and beautiful paleomagnetic data.

As the true polar wander hypothesis predicted, the Italian data indicate an ~12˚ tilt of the planet 84 million years ago. The team also found that Earth appears to have corrected itself—after tipping on its side, Earth reversed course and rotated right back, for a total excursion of nearly 25˚ of arc in about five million years. Certainly, this was a cosmic "yo-yo.

Ross N. Mitchell et al, A Late Cretaceous true polar wander oscillation, Nature Communications (2021). DOI: 10.1038/s41467-021-23803-8

https://phys.org/news/2021-10-earth-side-million-years.html?utm_sou...

Part 2

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Comment by Dr. Krishna Kumari Challa on October 19, 2021 at 10:44am

Did the Earth tip on its side 84 million years ago?

scientists have found more evidence that Earth tips over from time to time. We know that the continents are moving slowly due to plate tectonics, but continental drift only pushes the tectonic plates past each other. It has been debated for the past few decades whether the outer, solid shell of the Earth can wobble about, or even tip over relative to the spin axis. Such a shift of Earth is called "true polar wander," but the evidence for this process has been contentious. New research published in Nature Communications, led by the Earth-Life Science Institute (ELSI) and Institute of Geology and Geophysics in Beijing, provides some of the most convincing evidence to date that such planetary tipping has indeed occurred in Earth's past.

True polar wander bears some dissecting. The Earth is a stratified ball, with a solid metal inner core, a liquid metal outer core, and a solid mantle and overriding crust at the surface which we live on. All of this is spinning like a top, once per day. Because the Earth's outer core is liquid, the solid mantle and crust are able to slide around on top of it. Relatively dense structures, such as subducting oceanic plates and massive volcanoes like Hawaii, prefer to be near the Equator, in the same way that your arms like to be out to your side when you are spinning around in an office chair.

Despite this wandering of the crust, Earth' magnetic field is generated by electrical currents in the convecting liquid Ni-Fe metal of the outer core. On long time scales, the overlying wander of the mantle and crust does not affect the core, because those overlying rock layers are transparent to Earth's magnetic field. In contrast, the convection patterns in this outer core are actually forced to dance around Earth's rotation axis, which means that the overall pattern of Earth's magnetic field is predictable, spreading out in the same fashion as iron filings lining up over a small bar magnet. Hence, these data provide excellent information about the direction of the North and South geographic poles, and the tilt gives the distance from the poles (a vertical field means you are at the pole, horizontal tells us it was on the Equator). Many rocks actually record the direction of the local magnetic field as they form, in much the same way that a magnetic tape records your music. For example, tiny crystals of the mineral magnetite produced by some bacteria actually line up like tiny compass needles, and get trapped in the sediments when the rock solidifies. This "fossil" magnetism can be used to track where the spin axis is wandering relative to the crust.

Imagine looking at Earth from space. True polar wander would look like the Earth tipping on its side, and what's actually happening is that the whole rocky shell of the planet—the solid mantle and crust—is rotating around the liquid outer core. Although scientists can measure true polar wander occurring today very precisely with satellites, geologists still debate whether large rotations of the mantle and crust have occurred in Earth's past.

part 1

Researchers  came up with a plan for settling the debate once and for all.

Comment by Dr. Krishna Kumari Challa on October 19, 2021 at 10:05am

So-called junk DNA plays critical role in mammalian development

Nearly half of our DNA has been written off as junk, the discards of evolution: Sidelined or broken genes, viruses that got stuck in our genome and were dismembered or silenced, none of it relevant to the human organism or human evolution.

But research over the last decade has shown that some of this genetic "dark matter" does have a function, primarily in regulating the expression of host genes—a mere 2% of our total genome—that code for proteins. Biologists continue to find whether these regulatory sequences of DNA play essential or detrimental roles in the body or are merely incidental, an accident that the organism can live without.

A new study explored the function of one component of this junk DNA, transposons, which are selfish DNA sequences able to invade their host genome. The study shows that at least one family of transposons—ancient viruses that have invaded our genome by the millions—plays a critical role in viability in the mouse, and perhaps in all mammals. When the researchers knocked out a specific transposon in mice, half their mouse pups died before birth.

This is the first example of a piece of "junk DNA" being critical to survival in mammals.

In mice, this transposon regulates the proliferation of cells in the early fertilized embryo and the timing of implantation in the mother's uterus. The researchers looked in seven other mammalian species, including humans, and also found virus-derived regulatory elements linked to cell proliferation and timing of embryo implantation, suggesting that ancient viral DNA has been domesticated independently to play a crucial role in early embryonic development in all mammals.

Andrew J. Modzelewski et al, A mouse-specific retrotransposon drives a conserved Cdk2ap1 isoform essential for development, Cell (2021). DOI: 10.1016/j.cell.2021.09.021

https://phys.org/news/2021-10-so-called-junk-dna-critical-role.html...

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