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Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:25am

Researchers reprogram yeast cells to become microscopic drug factories

Since antiquity, cultures on nearly every continent have discovered that certain plant leaves, when chewed or brewed or rubbed on the body, could relieve diverse ailments, inspire hallucinations or, in higher dosages, even cause death. Today, pharmaceutical companies import these once-rare plants from specialized farms and extract their active chemical compounds to make drugs like scopolamine for relieving motion sickness and postoperative nausea, and atropine, to curb the drooling associated with Parkinson's disease or help maintain cardiac function when intubating COVID-19 patients and placing them on ventilators.

Now, Stanford engineers are recreating these ancient remedies in a thoroughly modern way by genetically reprogramming the cellular machinery of a special strain of yeast, effectively transforming them into microscopic factories that convert sugars and amino acids into these folkloric drugs, in much the same way that brewers' yeast can naturally convert sugars into alcohol.

Biosynthesis of medicinal tropane alkaloids in yeast, Nature (2020). DOI: 10.1038/s41586-020-2650-9 , www.nature.com/articles/s41586-020-2650-9

https://phys.org/news/2020-09-reprogram-yeast-cells-microscopic-dru...

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Has Earth's oxygen rusted the Moon for billions of years?

https://phys.org/news/2020-09-earth-oxygen-rusted-moon-billions.htm...

https://www.quora.com/q/sciencecommunication/Has-Earths-oxygen-rust...;   --check %%

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:17am

Study details how general anesthetics and 'benzos' act on receptors in the brain

As you drift into unconsciousness before a surgery, general anesthetic drugs flowing through your blood are putting you to sleep by binding mainly to a protein in the brain called the γ-aminobutyric acid type A (GABA_A) receptor. Now UT Southwestern scientists have shown exactly how anesthetics attach to the GABA_A receptor and alter its three-dimensional structure, and how the brain can tell the difference between anesthetics and the psychoactive drugs known as benzodiazepines—which also bind to the GABA_A receptor. The findings were published online today in the journal Nature.

The GABA_A receptor is an ion channel; when it's in an open conformation, it allows chloride ions to flow through. This movement of ions decreases the signaling of brain cells, calming brain activity. So stimulating the GABA_A receptor—as anesthetics, benzodiazepines, alcohol, anti-seizure, and some sleep medications all do—quiets the brain in a variety of ways.

The team discovered that both general anesthetics and diazepam could bind to multiple places on the GABA_A molecule. One site—dubbed the "benzo site" in earlier research—was unique to the diazepam. But another site overlapped between the two drug types. When diazepam was present at high enough doses, it bound to this site that was more often used by the anesthetics. This observation could explain why high doses of benzodiazepines like diazepam can have anesthetic-like effects. The researchers also found differences among the general anesthetics; phenobarbital, for instance, bound to a place on GABA_A that neither etomidate nor propofol attached, and seemed to be less choosy about where it bound.

Shared structural mechanisms of general anaesthetics and benzodiazepines, Nature (2020). DOI: 10.1038/s41586-020-2654-5 , www.nature.com/articles/s41586-020-2654-5

https://phys.org/news/2020-09-anesthetics-benzos-receptors-brain.ht...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:06am

Heaviest black hole merger is among three recent gravitational wave discoveries

Scientists observed what appears to be a bulked-up black hole tangling with a more ordinary one. They detected two black holes merging, but one of the black holes was 1 1/2 times more massive than any ever observed in a black hole collision. The researchers believe the heavier black hole in the pair may be the result of a previous merger between two black holes.This type of hierarchical combining of black holes has been hypothesized in the past but the observed event, labeled GW190521, would be the first evidence for such activity. 

The scientists identified the merging black holes by detecting the gravitational waves—ripples in the fabric of space-time—produced in the final moments of the merger.

The larger black hole in the merging pair has a mass 85 times greater than the sun. One possible scenario suggested by the new papers is that the larger object may have been the result of a previous black hole merger rather than a single collapsing star. According to current understanding, stars that could give birth to black holes with masses between 65 and 135 times greater than the sun don't collapse when they die. Therefore, we don't expect them to form black holes.

All three events now observed, are novel with masses or mass ratios that we've never seen before

The research paper, "GW190521: A Binary Black Hole Coalescence with a Total Mass of 150 Solar Masses," was published in Physical Review Letters on September 2, 2020: DOI: 10.1103/PhysRevLett.125.101102

The research paper, "Properties and Astrophysical Implications of the 150 Solar Mass Binary Black Hole Merger GW190521," was published in Astrophysical Journal Letters on September 2, 2020: DOI: 10.3847/2041-8213/aba493

The research paper, "GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object," was published in Astrophysical Journal Letters on June 23, 2020.

The research paper, "GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses," has been accepted for publication in Physical Review D, and was published on Arxiv on April 17, 2020: arxiv.org/abs/2004.08342

https://phys.org/news/2020-09-heaviest-black-hole-merger-gravitatio...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 7:13am

Blood pressure-lowering is even more beneficial than previously thought

Blood pressure medication can prevent heart attacks and strokes -- even in people with normal blood pressure. That's the finding of a meta analysis

https://www.sciencedaily.com/releases/2020/09/200901094058.htm

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Origin of a complex life form revealed

https://phys.org/news/2020-09-complex-life-revealed.html?utm_source...

https://www.quora.com/q/sciencecommunication/Origin-of-a-complex-li...

Check %%

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 7:03am

Blood Replacement Rescues Mice from Stroke Damage

When mice that had suffered a stroke were given blood from a healthy donor, they experienced less tissue and neurological damage.

Researchers have partially mitigated the effects of an ischemic stroke in mice simply by replacing a small amount of their blood with that of a healthy donor. Days after receiving the transplant, mice had less tissue damage surrounding the clot and suffered fewer neurological side effects compared to mice that had not received a blood infusion. 

The results, published August 25 in Nature Communications, highlight the link between strokes in the brain and the immune system. At least some of the damage caused by strokes, the authors say, is the result of an overreactive immune response during which cells sent to an injury to fight infection and facilitate repair instead harm sensitive brain tissue. 

In the moments following a stroke, the body activates a complex immunological response, funneling messenger molecules past the blood-brain barrier and into the blood to recruit immune cells to the damaged area. Neutrophils—white blood cells that are often the first to arrive—increase the levels of an enzyme called MMP-9 that degrades the blood-brain barrier further, the better to allow more immune cells and signaling molecules to pass through. In some instances, the body can release too many of these molecules, such as cytokines, into the blood at once, and the resulting cytokine storm can damage brain tissue surrounding a clot, causing inflammation and degeneration of brain tissue.

To better understand the immunological link between brain and blood, the researchers used a mouse model to mimic an ischemic stroke that was subsequently cleared by the scientists after 90 minutes. Between six and seven hours after the stroke, the mice received a blood transfusion of either 250 or 500 microliters of blood from a healthy donor, roughly 10 percent to 20 percent of a mouse’s total blood volume, after the same volume had been removed from the animal. One hour later, the scientists tested the permeability of the blood-brain barrier, followed by a measure of the amount of damaged brain tissue 24 hours after treatment.

Mice that received blood replacements suffered fewer ill effects than control mice, with the benefits being strongest in the group receiving a larger volume of new blood. The extent of tissue damage surrounding the clot decreased by as much as 70 percent to 80 percent, and cognitive defects brought on by the stroke improved in treated mice. Both the decrease in tissue damage and the rescuing of neurological deficits persisted for at least three days after the initial stroke.

The broader effect of replacing blood seems to be a dampening of the immune response.

https://www.nature.com/articles/s41467-020-17930-x

https://www.the-scientist.com/news-opinion/blood-replacement-rescue...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 6:15am

The Electromagnetic Spectrum

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 6:12am

The coronavirus is most deadly if you are older and male — new data reveal the risks

https://www.nature.com/articles/d41586-020-02483-2?utm_source=Natur...

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https://theconversation.com/are-women-leaders-really-doing-better-o...

Are women leaders really doing better on coronavirus? The data backs it up

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 Is a Bradykinin Storm Brewing in COVID-19?

Excess of the inflammatory molecule bradykinin may explain the fluid build-up in the lungs of patients with coronavirus infections. Clinical trials of inhibitors are putting this hypothesis to the test.

https://www.the-scientist.com/news-opinion/is-a-bradykinin-storm-br...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 6:01am

Why different measurements of material properties sometimes give different results

https://phys.org/news/2020-09-material-properties-results.html?utm_...

https://www.quora.com/q/sciencecommunication/Why-different-measurem...   - check %%

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A Strange Form of Life Could Flourish Deep Inside of Stars, Physicists Say

https://www.sciencealert.com/physicists-argue-that-life-based-on-co...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 5:53am

Brain protein linked to seizures, abnormal social behaviors

A research team  has found a new mechanism responsible for the abnormal development of neuronal connections in the mouse brain that leads to seizures and abnormal social behaviors.

The researchers focused on the area of the brain called hippocampus, which plays an important role in learning and social interactions; and synapses, which are specialized contacts between neurons.

Each neuron in the brain receives numerous excitatory and inhibitory synaptic inputs. The balance between excitation and inhibition in neuronal circuits, known as E/I balance and thought to be essential for circuit function and stability and important for information processing in the central nervous system, can play a role in causing many neurological disorders, including epilepsy, autism spectrum disorder, and schizophrenia.

The researchers also focused on a protein called ephrin-B1, which spans the membrane surrounding the cell and plays a role in maintaining the nervous system. The goal of their study was to determine if the deletion or over-production of ephrin-B1 in astrocytes—glial cells in the brain that regulate synaptic connections between neurons—affects synapse formation and maturation in the developing hippocampus and alters the E/I balance, leading to behavioral deficits.

 They found the changes in the E/I balance are regulated by astrocytes in the developing brain through the ephrin protein. Further, astrocytic ephrin-B1 is linked to the development of inhibitory networks in the hippocampus during a critical developmental period, which is a new and unexpected discovery. Specifically, the researchers show the loss of astrocytic ephrin-B1 tilts the E/I balance in favor of excitation by reducing inhibition, which then hyperactivates the neuronal circuits. This hyperactivity manifests as reduced sociability in the mice and suggests they can serve as a new model to study autism spectrum disorder.

Amanda Q Nguyen et al, Astrocytic ephrin-B1 controls excitatory-inhibitory balance in developing hippocampus, The Journal of Neuroscience (2020). DOI: 10.1523/JNEUROSCI.0413-20.2020

https://medicalxpress.com/news/2020-09-brain-protein-linked-seizure...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 5:43am

Researchers shed light on split-second decision making

A little understood region of the cerebellum plays a critical role in making split-second 'go-no go' decisions, according to a new study from researchers.

Employing mice the team used a multiphoton microscope that peered into the brains of the free-moving rodents as they decided whether or not to lick a water solution.

The researchers focused specifically on the molecular layer interneurons (MLIs) in the cerebellum. The mice were given a sugar water reward if they licked a water spout in the presence of a specific, pleasant odour and they avoided a timeout when they refrained from licking in the presence of unscented mineral oil.

At first, the MLI responses did not differ between odors. But with learning, the reward odor prompted a large increase in MLI calcium responses. When the stimuli were reversed, the MLI switched responses to the odors.

When the scientists intervened with chemogenetic agents to inhibit MLI activity, the mice floundered and became less effective in making `go-no go' decisions.

The data indicate that the MLIs have a role in learning valence. That is, it helps determine whether something is good for me or not.

The findings further illuminate the function of the cerebellum, long associated primarily with movement. But it also plays a key role in cognition and emotion and is associated with non-motor conditions such as autism spectrum disorders

A lot of learning goes on inside the cerebellum. The cerebellum may also be the place where quick choice arises. This study shows that it also coordinates both motion and decision making, when to go or not to go. And decision making.

Ming Ma et al, Molecular layer interneurons in the cerebellum encode for valence in associative learning, Nature Communications (2020). DOI: 10.1038/s41467-020-18034-2

https://medicalxpress.com/news/2020-09-split-second-decision.html?u...

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