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Comment by Dr. Krishna Kumari Challa on June 17, 2022 at 12:21pm

Climate change catastrophe: Phytoplankton Productivity Down 65%

Comment by Dr. Krishna Kumari Challa on June 16, 2022 at 11:10am

A Common Epilepsy Drug Causes Birth Defects, And We May Finally Know Why

Valproic acid – a drug commonly used to treat epilepsy and bipolar disorder – can cause birth defects and developmental disorders if taken during pregnancy, but the reason why has long been a mystery.

Now, in a study using mice and human tissue, scientists discovered that the medication locks some embryonic cells into a suspended state where they can't properly grow or divide.

By forcing key stem cellss into this state, called senescence, valproic acid may disrupt brain development in the womb and therefore cause cognitive and developmental disorders down the line, according to the study, published Tuesday (June 14) in the journal PLOS Biology.

An estimated 30 to 40 percent of infants exposed to the drug in the womb develop cognitive impairments or autism spectrum disorder, the study authors noted in their report, and these laboratory studies hint at why that happens. 

In a subset of affected children, valproic acid exposure can also cause birth defects beyond the brain, including heart malformations and spina bifida, where part of the spinal column doesn't form properly and thus leaves the spinal cord exposed.

However, the new study suggests that these physical birth defects, though also linked to valproic acid, are triggered by a different mechanism than the cognitive impairment.

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pb...

Comment by Dr. Krishna Kumari Challa on June 16, 2022 at 9:27am

Gender Inclusive Science Communication-Opportunities & Challenges

Comment by Dr. Krishna Kumari Challa on June 16, 2022 at 8:56am

New work upends understanding of how blood is formed

The origins of our blood may not be quite what we thought. Using cellular "barcoding" in mice, a groundbreaking study finds that blood cells originate not from one type of mother cell, but two, with potential implications for blood cancers, bone marrow transplant, and immunology.

Till now people thought that  most of our blood comes from a very small number of cells that eventually become blood stem cells, also known as hematopoietic stem cells. Scientists are now  surprised to find another group of progenitor cells that do not come from stem cells. They make most of the blood in fetal life until young adulthood, and then gradually start decreasing. 

The researchers are now following up to see if the findings also apply to humans. If so, these cells, known as embryonic multipotent progenitor cells (eMPPs), could potentially inform new treatments for boosting aging people's immune systems. They could also shed new light on blood cancers, especially those in children, and help make bone marrow transplants more effective.

Researchers applied a barcoding technique they developed several years ago and documented in Cell. Using either an enzyme known as transposase or CRISPR gene editing, they inserted unique genetic sequences into embryonic mouse cells in such a way that all the cells descended from them also carried those sequences. This enabled the team to track the emergence of all the different types of blood cells and where they came from, all the way to adulthood.

Through barcoding, the researchers found that eMPPs, as compared with blood stem cells, are a more abundant source of most lymphoid cells important to the immune responses, such as B cells and T cells. They think the decrease in eMPPs that they observed with age may explain why people's immunity weakens as they get older.They are now  trying to understand why these cells peter out in middle age, which could potentially allow us to manipulate them with the goal of rejuvenating the immune system.

In theory, there could be two approaches: extending the life of eMPP cells, perhaps through growth factors or immune signaling molecules, or treating blood stem cells with gene therapy or other approaches to make them more like eMPPs.

Finally, the recognition that there are two types of mother cells in the blood could revolutionize bone marrow transplant. 

 Fernando Camargo, Lifelong multilineage contribution by embryonic-born blood progenitors, Nature (2022). DOI: 10.1038/s41586-022-04804-z. www.nature.com/articles/s41586-022-04804-z

Sarah Bowling et al, An Engineered CRISPR-Cas9 Mouse Line for Simultaneous Readout of Lineage Histories and Gene Expression Profiles in Single Cells, Cell (2020). DOI: 10.1016/j.cell.2020.04.048

Comment by Dr. Krishna Kumari Challa on June 15, 2022 at 10:29am

Shedding light on how bacteria communicate their way to causing infection

Scientists have identified proteins that prevent a bacterial cell from becoming misguided by its own messaging, allowing it to instead wait for collective communication from its group. The research is important because understanding this type of signaling, known as quorum sensing and integral to bacterial pathogens, opens the door to potential new drugs that can disrupt it and thwart infection. Findings were published in the Proceedings of the National Academy of Sciences. 

Sometimes  single-celled organisms need to work together with other cells.  Bacteria and other single-celled microbes can coordinate behaviors and act as a group via quorum sensing, in which cells produce and sense a small chemical signal that is shared within the population. As the signal is released from cells and reaches a high enough concentration in their environment, a quorum is achieved—certain genes are simultaneously activated and specific group behaviors are set in motion.

It's a strength-in-numbers approach that allows bacteria to join forces to do things they could not do by themselves, like causing infection in animals and plants, acquiring certain nutrients and competing against other microbes.

Bacterial infection often involves toxins that only harm the host at high levels, when produced by all bacterial cells at once. 

A major unresolved question about quorum sensing, the researchers said, has been why the signal that's produced inside an individual cell is not sensed by that same cell before it is released, spurring the cell into premature, solo action.
What prevents signal 'short-circuiting' from happening? A set of proteins called antiactivators are crucial for short-circuit prevention. The proteins work as a quorum sensing "tuner" by causing cells to be less sensitive to the quorum signal.

This research shows how bacteria put the brakes on quorum sensing to achieve true communication in a group.

In addition to helping the quest for new antibiotics that can inhibit quorum sensing in bacterial pathogens, the findings also provide background knowledge useful for the engineering of cells with new properties in a field called synthetic biology.

Antiactivators prevent self-sensing in quorum sensing, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2201242119.

Comment by Dr. Krishna Kumari Challa on June 15, 2022 at 9:57am

A few proteins form a little barrel, and as the protein is threaded through that little cylinder, it gets degraded. This inactivates and breaks down the protein. Many proteasomes are present in cells at any given time, he added, but what makes this particular proteasome (labeled 20S) special is that it can accept proteins that are already somewhat misfolded and would not fit in the other cellular trash cans.

The limiting cap present on many proteasomes is not there in the BAG2 condensates. These promising results could point to a way to interrupt the development of Alzheimer's disease, which is marked by an accumulation of misfolded tau.

Daniel C. Carrettiero et al, Stress routes clients to the proteasome via a BAG2 ubiquitin-independent degradation condensate, Nature Communications (2022). DOI: 10.1038/s41467-022-30751-4

Comment by Dr. Krishna Kumari Challa on June 15, 2022 at 9:56am

Scientists discover and characterize a novel membraneless organelle that could play a role in Alzheimer's treatment

Researchers  have discovered a novel organelle—a previously unknown cell structure whose function it is to help clean up faulty proteins in times of stress and keep cells functioning in top condition. Optimizing this membraneless organelle, which they call a BAG2 condensate, could lead to treatments for conditions that are the result of misfolded proteins, including Alzheimer's disease, Parkinson's disease and other neurodegenerative conditions. Their results are reported in a paper  and published in the journal Nature Communications.

People have known for quite a while that are a few objects floating around in cells that don't have membranes. And it's never been clear how they're held together, what they are and what they're doing until relatively recently.

Thanks to advanced imaging techniques, scientists have uncovered structures that were once invisible, revealing cells for the truly complex and sophisticated systems that they are.

Of particular interest are biomolecular condensates, which don't have the recognizable cell membrane enclosure, but instead, are separated from the surrounding cytoplasm by a difference in density that can be loosely compared to a drop of oil in water. This liquid-liquid phase separation creates a specialized, relatively concentrated environment for certain functions and reactions. For example, a stress granule is a membraneless organelle that appears when the cell is under stress—maybe there's too much glucose, maybe it's too hot or cold, maybe the cell is experiencing dehydration—and its job is to sweep up RNA floating around in the cytoplasm, storing those genetic instructions and pausing their translation into proteins. If your cell is under stress, you want to shut down making proteins so you can really conserve your energy and get past the stress.

But that's only part of the picture, according to the researchers.

When there's stress, what happens to the proteins that are already in the cell?. If they're under those stress conditions, some of those proteins could get damaged and they could misfold." Misfolds of the tau protein, for example, can become pathological and turn into the neurofibrillary tangles that characterize Alzheimer's disease.

This is where the researchers' newly discovered BAG2 condensate comes in. Named for the BAG2 protein that it contains, the organelle, they found, is capable of sweeping up these faulty proteins in the cytoplasm and stuffing them into a proteasome—the cell's version of a trash can—located in the organelle.

Part 1

Comment by Dr. Krishna Kumari Challa on June 14, 2022 at 12:39pm

Nanoparticle sensor can distinguish between viral and bacterial pne...

Many different types of bacteria and viruses can cause pneumonia, but there is no easy way to determine which microbe is causing a particular patient's illness. This uncertainty makes it harder for doctors to choose effective treatments because the antibiotics commonly used to treat bacterial pneumonia won't help patients with viral pneumonia. In addition, limiting the use of antibiotics is an important step toward curbing antibiotic resistance.

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Bacterial intimacy insights could help tackle antimicrobial resistance

One of the primary ways harmful bacteria acquire resistance to antibiotics is by receiving DNA from other bacteria that are already resistant. This DNA exchange is made via a process called conjugation, akin to bacterial sex, whereby two bacteria form an intimate attachment, and one transfers a packet of DNA to the other.

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Shedding light on how bacteria communicate their way to causing inf...

Oregon State University scientists have identified proteins that prevent a bacterial cell from becoming misguided by its own messaging, allowing it to instead wait for collective communication from its group.

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Polluted air cuts global life expectancy by two years

Microscopic air pollution caused mostly by burning fossil fuels shortens lives worldwide by more than two years, researchers reported Tuesday.

Comment by Dr. Krishna Kumari Challa on June 14, 2022 at 12:31pm

Study describes new way of generating insulin-producing cells

Researchers show how a molecule that they have identified stimulates the formation of new insulin-producing cells in zebrafish and mammalian tissue, through a newly described mechanism for regulating protein synthesis. The results are published in Nature Chemical Biology.

These findings indicate a new potential target for treating diabetes, in that researchers demonstrate a possible way of stimulating the formation of new insulin-producingcells.

Insulin injections and glucose-lowering drugs can control the disease, but not cure it.

One alternative could be a treatment that regulates blood glucose by increasing the number of insulin-producing pancreatic β cells.

The researchers has previously identified a small molecule able to stimulate the regeneration of insulin-producing β cells. This they did by analyzing a large quantity of substances in a zebra fish model.

In this present study, they examined the molecular mechanism of this stimulation.

By analyzing a large number of molecular interactions in yeast cells, the researchers show that their molecule binds to a protein called MNK2. Subsequent studies of zebrafish and cell cultures indicate that the molecule operates by regulating the translation of mRNA and boosting the synthesis of proteins, without which the formation of new β cells cannot be increased. Zebrafish given the molecule also showed lower levels of blood glucose than controls.

The study also shows that the molecule can induce the formation of new pancreatic β cells from pigs and stimulate the expression of insulin in human organoids (organ-like cell formations).

Scientists now will be studying the effect of this and similar molecules in human tissue and analyzing the molecule's target protein, MNK2, in tissue from healthy donors and donors with diabetes.

Olov Andersson, MNK2 deficiency potentiates β-cell regeneration via translational regulation, Nature Chemical Biology (2022). DOI: 10.1038/s41589-022-01047-x. www.nature.com/articles/s41589-022-01047-x

Comment by Dr. Krishna Kumari Challa on June 14, 2022 at 9:46am

The  results showed that differences in V1 surface area could predict measurements of people's contrast sensitivity. First, people with a large V1 had better overall contrast sensitivity than did those with a small V1 (the largest surface area being 1,776 square millimeters [mm2] and the smallest being 832 mm2). Second, people whose V1 had more cortical tissue processing visual information from a specific region in their field of view had higher contrast sensitivity at that region relative to those with less cortical tissue dedicated to the same region. Third, across participants, higher contrast sensitivity at a specific location (e.g., left) than at another location equidistant from fixation (e.g., above) corresponded to regions with more or less cortical tissue, respectively.

In sum, the more local V1 surface area dedicated to encoding a specific location, the better the vision at that location.

Linking individual differences in human primary visual cortex to contrast sensitivity around the visual field, Nature Communications (2022). DOI: 10.1038/s41467-022-31041-9

Part 2

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