Comment

Comment by Dr. Krishna Kumari Challa on August 26, 2023 at 12:03pm

Penguin Breeding Colonies Catastrophically Failing as Ice Vanishes in Antarctica

Sea ice loss in Antarctica during 2022's emperor penguin breeding season resulted in the complete failure of four out of the five breeding colonies in the Bellingshausen Sea.

Satellite imagery shows none of the chicks from those sites survived.

The devastating event is the first recorded widespread breeding failure of emperor penguins (Aptenodytes forsteri); but, if the loss of ice due to climate change continues, scientists warn, it won't be the last.

Researchers have never seen emperor penguins fail to breed, at this scale, in a single season. The loss of sea ice in this region during the Antarctic summer made it very unlikely that displaced chicks would survive.

We know that emperor penguins are highly vulnerable in a warming climate – and current scientific evidence suggests that extreme sea ice loss events like this will become more frequent and widespread.

For most of the year, there is a "skirt" of stable sea ice around Antarctica, attached to the land. This fast ice, as it is known, forms in April, during the Southern Hemisphere's autumn, and persists until January, or high summer. Emperor penguins make their breeding ground on this fast ice, laying their eggs in May and June. The incubation period for emperor penguins is around 65 days, but the chicks are pretty helpless until they fledge – that is, they grow out of their baby fluff into suitable plumage for swimming and diving in the gelid Antarctic waters. This usually happens between December and January. The breeding season of 2022 started off normally; the penguins laid their eggs in the autumn, and incubated and hatched them into the winter. Come spring, disaster struck. The fast ice retreated and broke up early. By the beginning of summer, the extent of the Antarctic sea ice was consistent with the all-time low recorded the previous year, in summer 2021. The region most impacted was the Bellingshausen Sea, towards the west of the Antarctic peninsula, where some regions saw a 100 percent loss in sea ice extent. Every year, emperor penguins return to the same five sites in the Bellingshausen Sea to lay their eggs and raise their chicks. These five colonies range in size from an average of around 650 breeding pairs to 3,500 breeding pairs. By December 2022, four of those five sites disappeared as the ice on which they relied melted into the waves. At only one site, Rothschild Island, with 650 breeding pairs, did chicks manage to fledge successfully. Researchers found no sign of the rest of the babies. Emperor penguin colonies can be found around the entire perimeter of the Antarctic continent, but the breeding failure of these select few in the Bellingshausen Sea represent the first of what is likely to be many.

An early sign of extinction? Maybe!

https://www.nature.com/articles/s43247-023-00927-x

Comment by Dr. Krishna Kumari Challa on August 26, 2023 at 9:21am

Burning Forever Chemicals With Water

Forever Chemicals, also known as PFAS, are extremely useful industrial chemicals, but they can also leak into the environment, your drinking water, and your blood. And they last (practically) forever. But now chemists have a new way to destroy them: burning them with water.

Comment by Dr. Krishna Kumari Challa on August 26, 2023 at 8:42am

Paper drinking straws may be harmful and may not be better for the environment than plastic versions, researchers warn

"Eco-friendly" paper drinking straws contain long-lasting and potentially toxic chemicals, a new study has concluded.

Researchers tested 39 brands of straws for the group of synthetic chemicals known as poly- and perfluoroalkyl substances (PFAS).

PFAS were found in the majority of the straws tested and were most common in those made from paper and bamboo, found the study, published in Food Additives & Contaminants.

PFAS are used to make everyday products, from outdoor clothing to non-stick pans, resistant to water, heat and stains. However, they are potentially harmful to people, wildlife and the environment. They break down very slowly over time and can persist over thousands of years in the environment, a property that has led to them being known as "forever chemicals."

They have been associated with a number of health problems, including lower response to vaccines, lower birth weight, thyroid disease, increased cholesterol levels, liver damage, kidney cancer and testicular cancer.

Straws made from plant-based materials, such as paper and bamboo, are often advertised as being more sustainable and eco-friendly than those made from plastic. However, the presence of PFAS in these straws means that's not necessarily true.

The most commonly found PFAS, perfluorooctanoic acid  (PFOA), has been banned globally since 2020.

Also detected were trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMS), "ultra-short chain" PFAS which are highly water soluble and so might leach out of straws into drinks.

The PFAS concentrations were low, and bearing in mind that most people tend to only use straws occasionally, pose a limited risk to human health. However, PFAS can remain in the body for many years and concentrations can build up over time. Small amounts of PFAS, while not harmful in themselves, can add to the chemical load already present in the body.

The presence of the chemicals in almost every brand of paper straw means it is likely that it was, in some cases, being used as a water-repellent coating, say the researchers.

The presence of PFAS in paper and bamboo straws shows they are not necessarily biodegradable. As they did not detect any PFAS in stainless steel straws, the researchers are advising consumers to use this type of straw—or just avoid using straws at all.

Assessment of poly- and perfluoroalkyl substances (PFAS) in commercially available drinking straws using targeted and suspect screening approaches, Food Additives & Contaminants (2023). DOI: 10.1080/19440049.2023.2240908. www.tandfonline.com/doi/full/1 … 9440049.2023.2240908

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 12:38pm

Science and non-English-speaking scientists

Most journals offer minimal support for scientists who don't speak fluent English. An analysis of 736 biological-science journals found that only 2 stated that manuscripts would not be rejected solely on the .... A survey of the editors-in-chief of 262 of these journals found that only 6% instructed reviewers not to base their assessments solely on language proficiency. Less than 10% of journals offered author guidelines in at least one language other than English or allowed authors to publish articles in other languages.

Abstract

Scientific knowledge is produced in multiple languages but is predominantly published in English. This academic publishing practice creates a language barrier to the generation and transfer of scientific knowledge between communities with diverse linguistic backgrounds, hindering the ability of scholars and communities to address global challenges and achieve diversity and equity in science, technology, engineering, and mathematics (STEM). To overcome those barriers, publishers and journals should provide a fair system that supports non-native English speakers and disseminates knowledge across the globe. Researchers surveyed policies of 736 journals in biological sciences to assess their linguistic inclusivity, identify predictors of inclusivity, and propose actions to overcome language barriers in academic publishing. Their assessment revealed a grim landscape where most journals were making minimal efforts to overcome language barriers in academic publishing. The Impact Factor of journals was negatively associated with the adoption of a number of inclusive policies whereas the ownership by a scientific society tended to have a positive association. Counter to their expectations, the linguistic diversity of editorial boards and the Open Access model did not have a major positive association with the adoption of linguistically inclusive policies. The researchers proposed a set of actions to overcome language barriers in academic publishing, including the revision of exclusionary practices, clear communication of linguistic policies in author guidelines, and renegotiation of power dynamics between publishers and editorial boards. Academic publishing requires a change to support scholars and communities with limited English proficiency and scientific societies are well positioned to lead this cultural shift.

Nature 
Reference: EcoEvoRxiv preprint (not peer reviewed)

https://ecoevorxiv.org/repository/view/5475/

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 11:57am

How the 'treadmill conveyor belt' ensures proper cell division

Researchers at the Center for Genomic Regulation (CRG) have discovered how proteins work in tandem to regulate "treadmilling," a mechanism used by the network of microtubules inside cells to ensure proper cell division. The findings are published in the Journal of Cell Biology.

Microtubules are long tubes made of proteins that serve as infrastructure to connect different regions inside of a cell. Microtubules are also critical for cell division, where they are key components of the spindle, the structure which attaches itself to chromosomes and pulls them apart into each new cell.

For the spindle to function properly, cells rely on microtubules to "treadmill." This involves one end of the microtubule (known as the minus end) to lose components while the other (the plus end) adds components. The effect is like that of a treadmill conveyor belt, where the microtubules appear to be moving continuously without changing their overall length.

Treadmilling is crucial for cell division. The most likely theory is that treadmilling helps the cell regulate its attachments to chromosomes by maintaining tension. Because microtubules are often growing from their plus ends, this tension can be provided by constant shrinking from the minus end.

The authors of the study used various isolated proteins known to play a central role in microtubule biology, putting them together in a test tube and visualizing them using a microscope.

Three proteins were found to be critical for regulating treadmilling: KIF2A, a protein belonging to a larger family of proteins that dismantles microtubules, the γ-tubulin ring complex (γ-TuRC), a scaffold for microtubules to grow from, and spastin, an enzyme that acts like a scissor cutting microtubules.

The researchers found that the correct control of treadmilling requires the coordinated action of all three proteins. 

Gil Henkin et al, The minus end depolymerase KIF2A drives flux-like treadmilling of γTuRC-uncapped microtubules, Journal of Cell Biology (2023). DOI: 10.1083/jcb.202304020

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 11:53am

 Unlocking the secrets to brain diseases: When proteins get stuck at the solid phase

Many diseases affecting the brain and nervous system are linked to the formation of protein aggregates, or solid condensates, in cells from their liquid form condensate, but little is known about this process.

This liquid-to-solid transition can trigger the formation of what are called amyloid fibrils. These can further form plaques in neurons causing neurodegenerative diseases such as Alzheimer's.

Biomedical Engineers have now developed sophisticated optical techniques to monitor at close range the process by which these protein aggregates form.

By testing a protein associated with amyotrophic lateral sclerosis—ALS disease, which affected astrophysicist Professor Stephen Hawking—the Sydney engineers closely monitored the transition of this protein from its liquid to solid phase.

Proteins regularly form condensates during liquid-to-liquid phase separation in a wide range of critical and healthy biological functions, such as the formation of human embryos. This process assists biochemical reactions where protein concentrations are critical and also promotes healthy protein–protein interactions. However, this process also increases the risk of dysfunctional aggregation, where unhealthy aggregates of solid proteins form in human cells.

This can lead to aberrant structures associated with neurodegenerative diseases because the proteins no longer exhibit rapid reversibility back to liquid form.  It is therefore crucial to monitor condensate dynamics, as they directly affect pathological states.

The world-first nanoscale optical observation of this process has allowed the team to determine that the transition from liquid to solid protein starts at the interface of the protein condensates. This window onto the phase transition also revealed that the internal structures of these protein agglomerates are heterogenous, where previously they were thought to be homogeneous.

Yi Shen et al, The liquid-to-solid transition of FUS is promoted by the condensate surface, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2301366120

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 11:41am

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 11:00am

Study shows that astrocytes in the cortex modulate the dominant behavior of male mice

The social behavior of animals has been the key focus of extensive neuroscience and biomedical studies, as it is often aligned with behaviors observed in humans. Better understanding these behaviors and the neural processes underpinning them could ultimately also have implications for the treatment of different psychiatric disorders that affect how humans socialize with others.

Researchers recently conducted a study specifically exploring male dominance behavior among male mice. These behaviours naturally lead to the formation of social hierarchies among groups of mice, with some males accessing more food and water than others. 

A recent paper, published in Nature Neuroscience, highlights the role of astrocytes in the outer layer of the brain (i.e., the cortex), in modulating the dominance behavior of male mice. In addition, it sheds some light on the specific neural processes through which astrocytes modulate these behaviours.

The results gathered by the researchers hint at the involvement of communication between dmPFC astrocytes and neurons in the dominant behaviour of male mice. 

This work implies that astrocytes also play critical role in computing and processing high-order brain functions. It also suggests that such intercellular interplay may decipher the etiology of many psychiatric disorders.

 Kyungchul Noh et al, Cortical astrocytes modulate dominance behavior in male mice by regulating synaptic excitatory and inhibitory balance, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01406-4

Nguyen T. Phi et al, Control of social hierarchy beyond neurons, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01392-7

Comment by Dr. Krishna Kumari Challa on August 25, 2023 at 9:59am

Scientists discover a previously unknown way cells break down proteins

Short-lived proteins control gene expression in cells to carry out a number of vital tasks, from helping the brain form connections to helping the body mount an immune defense. These proteins are made in the nucleus and are quickly destroyed once they've done their job.

Despite their importance, the process by which these proteins get broken down and removed from cells once they are no longer needed has eluded scientists for decades—until now.

It is well established that cells can break down proteins by tagging them with a small molecule called ubiquitin. The tag tells the proteasome that the proteins are no longer needed, and it destroys them. 

However, sometimes the proteasome breaks down proteins without the help of ubiquitin tags, leading researchers to suspect that there was another, ubiquitin-independent mechanism of protein degradation.

Researchers now  identified a protein called midnolin that plays a key role in degrading many short-lived nuclear proteins. The study shows that midnolin does so by directly grabbing the proteins and pulling them into the cellular waste-disposal system, called the proteasome, where they are destroyed.

Because the proteins broken down by this process modulate genes with important functions related to the brain, the immune system, and development, scientists may eventually be able to target the process as a way of controlling protein levels to alter these functions and correct any dysfunction.

Xin Gu et al, The midnolin-proteasome pathway catches proteins for ubiquitination-independent degradation, Science (2023). DOI: 10.1126/science.adh5021.

Comment by Dr. Krishna Kumari Challa on August 24, 2023 at 1:08pm

Spectroscopy, Explained

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