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Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 9:42am

When the human brain goes diving

7,108 views • 23 Jun 2021 • Visualisation showing the physiological responses of a freediver making a breath-hold dive to 107m - including heart rate, arterial blood oxygen saturation and cerebral blood oxygen saturation. Physiological responses were measured using non-invasive, wearable near-infrared spectroscopy. Here's a link to the published work - McKnight et al 2021, When the human brain goes diving: using near-infrared spectroscopy to measure cerebral and systemic cardiovascular responses to deep, breath-hold diving in elite freedivers: https://doi.org/10.1098/rstb.2020.0349

Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 9:23am

Gene editing 'blocks virus transmission' in human cells

Scientists have used CRISPR gene-editing technology to successfully block the transmission of the SARS-CoV-2 virus in infected human cells, according to research released recently that could pave the way for COVID-19 treatments.

Writing in the journal Nature Communications, researchers in Australia said the tool was effective against viral transmissions in lab tests, adding that they hoped to begin animal trials soon.

CRISPR, which allows scientists to alter DNA sequences and modify gene function, has already shown promise in eliminating the genetic coding that drives the development of children's cancer.

The team in Tuesday's study used an enzyme, CRISPR-Cas13b, that binds to relevant RNA sequences on the novel coronavirus and degrades the genome it needs to replicate inside human cells.

 The team had designed the CRISPR tool to recognize SARS-CoV-2, the virus responsibly for COVID-19.

Once the virus is recognized, the CRISPR enzyme is activated and chops up the virus.

Mohamed Fareh et al, Reprogrammed CRISPR-Cas13b suppresses SARS-CoV-2 replication and circumvents its mutational escape through mismatch tolerance, Nature Communications (2021). DOI: 10.1038/s41467-021-24577-9

https://phys.org/news/2021-07-gene-blocks-virus-transmission-human....

Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 9:17am

Tree rings show record of newly identified extreme solar activity event

The sun constantly emits a stream of energetic particles, some of which reach Earth. The density and energy of this stream form the basis of space weather, which can interfere with the operation of satellites and other spacecraft. A key unresolved question in the field is the frequency with which the sun emits bursts of energetic particles strong enough to disable or destroy space-based electronics.

One promising avenue for determining the rate of such events is the dendrochronological record. This approach relies on the process by which a solar energetic particle (SEP) strikes the atmosphere, causing a chain reaction that results in the production of an atom of carbon-14. This atom subsequently can be incorporated into the structure of a tree; thus, the concentration of carbon-14 atoms in a tree ring can indicate the impact rate of SEPs in a given year.

To date, three events of extreme SEP production are well described in literature, occurring approximately in the years 660 BCE, 774–775 CE, and 992–993 CE. Each event was roughly an order of magnitude stronger than any measured in the space exploration era. Miyake et al. describe such an event, which occurred between 5411 BCE and 5410 BCE. Because of this burst, atmospheric carbon-14 increased 0.6 percent year over year in the Northern Hemisphere and was sustained for several years before dropping to typical levels.

Using statistical methods, the researchers identified a pattern of small carbon-14 fluctuations consistent with the sun's 11-year solar cycle; the event recorded in the tree ring occurred during a time of solar maximum. Notably, other evidence suggests that the sun was also undergoing a decades-long period of increasing activity.

If an extreme SEP burst is indeed the cause of the additional carbon-14, then these observations could aid in forecasting future events. However, tree ring  measurements cannot rule out other extraterrestrial causes, such as a nearby supernova explosion. Confirmation will require isotopic measurements of beryllium and chlorine taken from ice cores, according to the authors.

F. Miyake et al, A Single‐Year Cosmic Ray Event at 5410 BCE Registered in 14 C of Tree Rings, Geophysical Research Letters (2021). DOI: 10.1029/2021GL093419

https://phys.org/news/2021-07-tree-newly-extreme-solar-event.html?u...

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Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 9:12am

Are silver nanoparticles a silver bullet against microbes?

Antimicrobials are used to kill or slow the growth of bacteria, viruses and other microorganisms. They can be in the form of antibiotics, used to treat bodily infections, or as an additive or coating on commercial products used to keep germs at bay. These life-saving tools are essential to preventing and treating infections in humans, animals and plants, but they also pose a global threat to public health when microorganisms develop resistance to them, a concept known as antimicrobial resistance.

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Tree rings show record of newly identified extreme solar activity e...

The sun constantly emits a stream of energetic particles, some of which reach Earth. The density and energy of this stream form the basis of space weather, which can interfere with the operation of satellites and other spacecraft. A key unresolved question in the field is the frequency with which the sun emits bursts of energetic particles strong enough to disable or destroy space-based electronics.

Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 9:08am

Electric signals between individual cardiac cells regulate heartbeat

The rhythm in a working heart is regulated by electrical impulses. Disturbances of this bioelectrical process can result in cardiac arrhythmias, or irregularities in heartbeat—a common ailment that can lead to illness and death.

In Biophysics Reviews, researchers from Harvard Medical School provide a state-of-the-art update on how electrical impulses in the heart travel from cell to cell.

A functioning heart contracts to pump blood to the body and the lungs. Within the heart, a pacemaker acts as an electrical clock, sending out a signal that tells the heart when to contract. The whole muscle moves together, because each individual cell inside of it contracts in a coordinated manner and within a short time interval.

In order to do so, the initial electrical impulse, sent by the pacemaker, rapidly spreads through cells across the heart.

If one cell is excited electrically and the other is not, the excited cell becomes positively charged inside, and the resting cell is still negatively charged inside. As a consequence, a voltage gradient builds up between the cells. If you have a voltage gradient and a pathway with a low electrical resistance, a local current will flow.

The connections between cells forming the low resistance pathway and facilitating the current flow are called gap junctions. Each consists of many channels, which are formed when specific proteins from one cell dock and fuse to the proteins from another cell. Kléber said the fusing proteins look like placing the tips of your fingers on one hand to the fingers on the other hand.

The scientists delve into the properties of gap junctions and their constituent proteins, the so-called connexins. Kléber said one reason gap junction channels are interesting is because they are a highly dynamic system in equilibrium. The creation, or synthesis, of the channels equals the destruction.

"The turnover is very short," he said. "On one hand, the system is very stable during your whole life. On the other hand, if you measure it, it is constantly cycling in periods of a few hours."

The proteins found in gap junctions are important for processes not directly related to cell-cell connections, like mitochondrial function which creates energy, and trafficking, which transports molecules from the site of synthesis to their site of action in the cell interior.

You have to refrain from the idea that if you define the role of a protein in the body, that it has only a single function.

"Coupling between cardiac cells - an important determinant of electrical impulse propagation and arrhythmogenesis" Biophysics Reviews, aip.scitation.org/doi/10.1063/5.0050192

https://medicalxpress.com/news/2021-07-electric-individual-cardiac-...

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Comment by Dr. Krishna Kumari Challa on July 14, 2021 at 5:51am

The World's Most Dangerous Blood Type

Comment by Dr. Krishna Kumari Challa on July 13, 2021 at 10:41am

Sex-specific immune response in COVID-19 linked to cellular metabolism

 Researchers studying COVID-19 patients have found a metabolic pathway that is highly correlated with immune responses only in male patients, a group known to be more likely to suffer severe cases and die of the disease, representing a potential target for therapeutic intervention. In a study published in the journal Science Signaling, the authors report that male COVID-19 patients were more likely than female patients or healthy control subjects to have elevated levels of kynurenic acid, a product of amino acid metabolism. High levels of kynurenic acid have been linked to several diseases, such as schizophrenia and HIV-related diseases. Male patients with severe COVID-19 cases were also more likely to have a high ratio of kynurenic acid to kynurenine, a byproduct of the amino acid L-tryptophan which is used to create the nutrient niacin. We know that men are at higher risk than women of contracting severe cases of COVID-19 and that sex differences in the body's immune responses  present a compelling explanation for this phenomenon.

We also know that immune responses are regulated in part by metabolites, and so these new findings offer a key window into the mechanisms underlying how this disease affects female and male patients differently

https://researchnews.cc/news/7739/Sex-specific-immune-response-in-C...

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Comment by Dr. Krishna Kumari Challa on July 13, 2021 at 10:06am

Comment by Dr. Krishna Kumari Challa on July 13, 2021 at 10:01am

Researchers unlock behavior of rare cells that evade antibiotics by 'playing dead'

Researchers have developed a new microfluidic platform to track a very rare type of cell that can survive antibiotic treatments. The results have important implications for microbiologists learning about the cellular control of bacterial physiology and for scientists looking to combat the emerging threat of antibiotic resistance bacteria that can lead to untreatable infections.

"Persister cells" are a very small subpopulation of cells that survive antibiotic treatment by staying dormant and then resume growth after the antibiotic has been removed. These cells are transient and are therefore harder to study and have no genetic changes, meaning that they cannot be identified using sequencing.

Since these "persister cells" are both rare and transient, a platform is needed to image cells over time with sufficiently large throughput. Now researchers from the University of Cambridge, Harvard Medical School and Harvard University have developed a platform designed to track more than 100,000 individual bacterial cells over hundreds of generations as they experience rounds of feast-and-famine cycles. An array of hundreds of thousands of traps are used to keep individual cells immobilized and infused with the contents from a growing culture—E. coli (Escherichia coli), normally found in the intestine, and Bacillus subtilis, commonly found in soil. A high-resolution microscope rapidly scans over each cell and tracks their fate over time. The results are reported in the journal Nature Microbiology.

Somenath Bakshi et al, Tracking bacterial lineages in complex and dynamic environments with applications for growth control and persistence, Nature Microbiology (2021). DOI: 10.1038/s41564-021-00900-4

https://phys.org/news/2021-07-behavior-rare-cells-evade-antibiotics...

Comment by Dr. Krishna Kumari Challa on July 13, 2021 at 9:47am

Carbon Capture

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