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Comment by Dr. Krishna Kumari Challa on August 26, 2024 at 10:39am

Hara, T. et al. Unveiling the Nature of Chemical Bonds in Real Space, Journal of the American Chemical Society (2024). DOI: 10.1021/jacs.4c05673

Part 2

Comment by Dr. Krishna Kumari Challa on August 26, 2024 at 10:38am

First visualization of valence electrons reveals fundamental nature of chemical bonding

The distribution of outermost shell electrons, known as valence electrons, of organic molecules was experimentally observed for the first time by a team led by Nagoya University in Japan. As the interactions between atoms are governed by the valence electrons, their findings shine light on the fundamental nature of chemical bonds, with implications for pharmacy and chemical engineering. The results were published in the Journal of the American Chemical Society.

The behavior of the electrons in atoms is complex, forming electron orbitals that have different functions depending on their closeness to the nucleus. The inner shell electrons, called core electrons, are used for self-stabilization and do not interact with other atoms. On the other hand, the outer electrons, or valence electrons, define most of the material's properties, especially during bonding with other atoms.

Understanding a material's properties requires extracting information about its valence electrons. However, it has been difficult to experimentally isolate only the valence electron information, leading to researchers having to rely on theoretical models and spectroscopy to estimate it. By conducting world-class synchrotron X-ray diffraction experiments at SPring-8, the research group discovered that it is possible to selectively extract only the valence electron density of atoms in a crystal.

They named this method the CDFS method. Using this method, they observed the electron state of the glycine molecule, a type of amino acid.

Although the method was relatively simple to perform, the result was impressive. The observed electron cloud did not exhibit the smooth, enveloping shape that many predicted, but rather a fragmented, discrete state.

To understand the nature of the results, the group made a colour map of their observations. In chemistry, a color map uses colors to display variations in datasets across a specific range. Such maps are often used in conjunction with spectroscopic techniques, imaging, and chemical analysis to provide an intuitive way to interpret complex datasets. The map of the cross-sectional view in the enlarged diagram clearly showed interruptions in the electron distribution surrounding the carbon atoms.

"When carbon forms bonds with surrounding atoms, it reconstructs its electron cloud to create hybridized orbitals. In this case, the outermost L-shell electrons have nodes based on their wave nature known as wave functions.
This means that due to the wave nature of electrons, there are parts of the hybrid orbitals where electrons are absent, much different to the image that many people have of a continuous 'cloud' of electrons.
The fragmented electron cloud distribution observed in the experiment demonstrates the quantum mechanical wave nature of electrons, as predicted by physics. To confirm whether the observed electron cloud accurately captures the true state, they conducted advanced quantum chemical calculations in collaboration with Hokkaido University that confirmed that the experimental and theoretical results matched perfectly.

Comment by Dr. Krishna Kumari Challa on August 26, 2024 at 10:21am

Sustainable solution to vitamin B12 deficiency

In new research published in the journal Discover Food, researchers report the use of state-of-the-art biotechnology to cultivate photosynthetically-controlled Spirulina, and produce carbon–neutral and nutritious biomass containing unopposed, biologically active vitamin B₁₂, in levels comparable to beef meat. This is the first time biologically active vitamin B₁₂ has been reported in Spirulina.

Their new study reveals a potential solution to one of the most widespread micronutrient deficiencies: vitamin B₁₂. With more than a billion individuals worldwide suffering from low levels of this essential vitamin, the reliance on meat and dairy products for adequate B₁₂ intake (2.4 µg/day) presents significant environmental challenges.

While Spirulina blue-green algae (Arthrospira platensis) has been proposed as a healthier and more sustainable substitute for meat and dairy, the so-called traditional Spirulina has fallen short as a viable alternative due to its content of pseudo-vitamin B₁₂, a form not bioavailable to humans. This limitation has hindered its potential to address vitamin B₁₂ deficiencies, and fully replace beef meat in human diets.

In the present study, the research team evaluated a biotechnology system developed by VAXA Technologies in Iceland, focusing on its engineering components, inputs (such as energy), and outputs, including biomass composition. The system employs photonic management (modified light conditions) to enhance active vitamin B₁₂ production in Spirulina, along with other bioactive  compounds with antioxidant, anti-inflammatory, and immune-boosting properties.

This innovative approach yielded carbon-neutral, nutritious biomass containing biologically active vitamin B12 at levels comparable to beef (1.64 µg/100g in PCS vs. 0.7–1.5 μg/100g in beef).

The findings demonstrate that photosynthetically controlled Spirulina can produce desirable levels of active vitamin B12, offering a sustainable alternative to traditional animal-source foods.

This breakthrough marks a significant step towards addressing global vitamin B12 deficiency sustainably, reducing reliance on environmentally taxing meat and dairy production.

A. Tzachor et al, Photonic management of Spirulina (Arthrospira platensis) in scalable photobioreactors to achieve biologically active unopposed vitamin B12, Discover Food (2024). DOI: 10.1007/s44187-024-00152-1

Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 12:28pm

Autism spectrum disorders linked to neurotransmitter switching in the brain

Autism spectrum disorders (ASD) involve mild to severe impairment of social, behavioral and communication abilities. These disorders can significantly impact performance at school, in employment and in other areas of life. 

Neurobiologists have now found evidence of altered development of the nervous system in mouse models of autism spectrum disorders. They linked environmentally induced forms of ASD to changes in neurotransmitters, the chemical messengers that allow neurons to communicate with each other. They also discovered that manipulating these neurotransmitters at early stages of development can prevent the appearance of autistic-like behaviours.

The researchers say the new results are consistent with other evidence that altering signaling in the nervous system during the early stages of development can later carry negative consequences as the brain matures.

Swetha K. Godavarthi et al, Embryonic exposure to environmental factors drives transmitter switching in the neonatal mouse cortex causing autistic-like adult behavior, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2406928121. doi.org/10.1073/pnas.2406928121

Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 12:25pm

How insulin, zinc and pH can block harmful protein clumps linked to type 2 diabetes

An estimated 462 million people around the world suffer from type 2 diabetes, a chronic disease in which the body has problems using sugar as a fuel, leading to a buildup of sugar in the blood and chronic health issues.

New research shows how zinc, pH levels and insulin work together to inhibit the buildup of protein clumps that contribute to this disease. The work, which points toward promising avenues for innovative treatments, was published in Communications Biology.

The research focuses on the intricate dance between insulin and the hormone amylin, or human islet amyloid polypeptide (hiAPP). Amylin is a naturally occurring peptide hormone that plays a role in regulating glycemia and energy balance. But human amylin can form amyloid fibers, which can destroy insulin-producing cells in the pancreas.

Amylin is produced in the pancreas alongside insulin and has a tendency to clump into aggregates called amyloid. They're like the plaques that form in the brain with Alzheimer's or Parkinson's disease.

For individuals with type 2 diabetes, amylin tends to cluster into harmful amyloid plaques, devastating the islet cells responsible for hormone production. However, insulin emerges as a potential hero, showing capabilities to hinder amylin's aggregation.

This study unravels the nuances of their interaction, alongside the roles of zinc and pH levels, bringing scientists closer to decoding the cellular intricacies of diabetes.

The results promise not just groundbreaking insights into this biomedical mystery, but also practical solutions. The research will help drug development aimed at neutralizing amylin's toxicity.

This could potentially revolutionize treatment approaches, offering hope to those battling this pervasive illness.

Samuel D. McCalpin et al, Zinc and pH modulate the ability of insulin to inhibit aggregation of islet amyloid polypeptide, Communications Biology (2024). DOI: 10.1038/s42003-024-06388-y

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Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 12:09pm

Mosquitoes sense infrared from body heat to help track humans down, study shows

While a mosquito bite is often no more than a temporary bother, in many parts of the world it can be scary. One mosquito species, Aedes aegypti, spreads the viruses that cause over 100,000,000 cases of dengue, yellow fever, Zika and other diseases every year. Another, Anopheles gambiae, spreads the parasite that causes malaria. The World Health Organization estimates that malaria alone causes more than 400,000 deaths every year. Indeed, their capacity to transmit disease has earned mosquitoes the title of deadliest animal.

Male mosquitoes are harmless, but females need blood for egg development. It's no surprise that there's over 100 years of rigorous research on how they find their hosts. Over that time, scientists have discovered there is no one single cue that these insects rely on. Instead, they integrate information from many different senses across various distances.

A team of researchers  has added another sense to the mosquito's documented repertoire: infrared detection. Infrared radiation from a source roughly the temperature of human skin doubled the insects' overall host-seeking behavior when combined with CO₂ and human odor.

The mosquitoes overwhelmingly navigated toward this infrared source while host seeking. The researchers also discovered where this infrared detector is located and how it works on a morphological and biochemical level. The results are detailed in the journal Nature.

Craig Montell, Thermal infrared directs host-seeking behaviour in Aedes aegypti mosquitoes, Nature (2024). DOI: 10.1038/s41586-024-07848-5. www.nature.com/articles/s41586-024-07848-5

Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 12:04pm

Inherited NUMTs are mostly benign, probably because they arise early in development and the harmful ones are weeded out.
But if a piece of mitochondrial DNA inserts itself within a gene or regulatory region, it could have important consequences on that person's health or lifespan. Neurons may be particularly susceptible to damage caused by NUMTs because when a neuron is damaged, the brain does not usually make a new brain cell to take its place.
The researchers' analysis showed that nuclear mitochondrial DNA insertion happens in the human brain—mostly in the prefrontal cortex—and likely several times over during a person's lifespan.
They also found that people with more NUMTs in their prefrontal cortex died earlier than individuals with fewer NUMTs. "This suggests for the first time that NUMTs may have functional consequences and possibly influence lifespan.
"NUMT accumulation can be added to the list of genome instability mechanisms that may contribute to aging, functional decline, and lifespan.
Stress accelerates NUMTogenesis
What causes NUMTs in the brain, and why do some regions accumulate more than others?

To get some clues, the researchers looked at a population of human skin cells that can be cultured and aged in a dish over several months, enabling exceptional longitudinal "lifespan" studies.

These cultured cells gradually accumulated several NUMTs per month, and when the cells' mitochondria were dysfunctional from stress, the cells accumulated NUMTs four to five times more rapidly.

This shows a new way by which stress can affect the biology of our cells.Stress makes mitochondria more likely to release pieces of their DNA and these pieces can then 'infect' the nuclear genome. It's just one way mitochondria shape our health beyond energy production.
Mitochondria are cellular processors and a mighty signaling platform. Now we know mitochondria can even change the nuclear DNA sequence itself.

Somatic nuclear mitochondrial DNA insertions are prevalent in the human brain and accumulate over time in fibroblasts, PLoS Biology (2024). On bioRxiv: DOI: 10.1101/2023.02.03.527065

Part 2

Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 12:00pm

Mitochondria are flinging their DNA into our brain cells, study shows

As direct descendants of ancient bacteria, mitochondria have always been a little alien. Now a study shows that mitochondria are possibly even stranger than we thought.

The study, titled "Somatic nuclear mitochondrial DNA insertions are prevalent in the human brain and accumulate over time in fibroblasts," appears in PLOS Biology.

Mitochondria in our brain cells frequently fling their DNA into the nucleus, the study found, where the DNA becomes integrated into the cells' chromosomes. And these insertions may be causing harm: Among the study's nearly 1,200 participants, those with more mitochondrial DNA insertions in their brain cells were more likely to die earlier than those with fewer insertions.
We used to think that the transfer of DNA from mitochondria to the human genome was a rare occurrence. It's stunning that it appears to be happening several times during a person's lifetime.

Researchers now found lots of these insertions across different brain regions, but not in blood cells, explaining why dozens of earlier studies analyzing blood DNA missed this phenomenon.

Mitochondria live inside all our cells, but unlike other organelles, mitochondria have their own DNA, a small circular strand with about three dozen genes. Mitochondrial DNA is a remnant from the organelle's forebears: ancient bacteria that settled inside our single-celled ancestors about 1.5 billion years ago.

In the past few decades, researchers discovered that mitochondrial DNA has occasionally "jumped" out of the organelle and into human chromosomes.

The mitochondrial DNA behaves similar to a virus in that it makes use of cuts in the genome and pastes itself in, or like jumping genes known as retrotransposons that move around the human genome.

The insertions are called nuclear-mitochondrial segments—NUMTs ("pronounced new-mites")—and have been accumulating in our chromosomes for millions of years.

As a result, all of us are walking around with hundreds of vestigial, mostly benign mitochondrial DNA segments in our chromosomes that we inherited from our ancestors.

Mitochondrial DNA insertions are common in the human brain Research in just the past few years has shown that "NUMTogenesis" is still happening today. "Jumping mitochondrial DNA is not something that only happened in the distant past

It's rare, but a new NUMT becomes integrated into the human genome about once in every 4,000 births. This is one of many ways, conserved from yeast to humans, by which mitochondria talk to nuclear genes.

Part 1

Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 11:54am

Researchers discover gene scissors that switch off with a built-in timer

CRISPR gene scissors, as new tools of molecular biology, have their origin in an ancient bacterial immune system. But once a virus attack has been successfully overcome, the cell has to recover.

Researchers  have discovered a timer integrated into the gene scissors that enables the gene scissors to switch themselves off. The results of the study have been published in the journal Nucleic Acids Research.

Sophie C Binder et al, The SAVED domain of the type III CRISPR protease CalpL is a ring nuclease, Nucleic Acids Research (2024). DOI: 10.1093/nar/gkae676

Some bacteria have developed CRISPR gene scissors in response to attacks by so-called phages. This bacterial immune system recognizes the phage genetic material, destroys it and thus protects against viral attacks.

When detecting phages, the type III variants of these immune systems produce messenger substances with cyclic oligoadenylates (cOAs), which the bacteria use to switch on a complex emergency plan. This ensures that a virus can be fought optimally and on a broad front.

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Comment by Dr. Krishna Kumari Challa on August 25, 2024 at 11:20am

Thyroid hormone fuels the drive to explore by rewiring brain circuits, new study suggests

Thyroid hormone plays a key role in regulating a range of physiologic functions, including metabolism, temperature, heart rate, and growth. It accomplishes this impressive array of activities by interacting with almost every organ system in the body. Yet despite a long history of research on how thyroid hormone influences different organs, its effects on arguably the most crucial organ—the brain—have remained shrouded in mystery.

Now, scientists have gained new insights into thyroid hormone's effects on the brain. The work, conducted in mice and published Aug. 22 in Cell, shows that thyroid hormone changes the wiring of brain circuits in a manner that drives animals to engage in exploratory behaviour. 

By simultaneously changing brain wiring and altering metabolic rate, the researchers concluded that thyroid hormone coordinates the brain and body to produce exploratory behavior when it is most needed—for example, during seasons when animals need to find mates or stockpile resources.

It's well known that thyroid hormone modulates metabolism, and now scientists have shown that it also modulates exploratory behaviours through direct action on the brain.

The findings also help elucidate how low levels of the hormone could lead to depressive states marked by a low desire to explore, while too much could precipitate manic states characterized by an extreme desire for exploration. Thus, the researchers see their work as an important step toward understanding how aberrant levels of thyroid hormone could contribute to certain psychiatric conditions.

Daniel Hochbaum et al, Thyroid hormone remodels cortex to coordinate body-wide metabolism and exploration, Cell (2024). DOI: 10.1016/j.cell.2024.07.041. www.cell.com/cell/fulltext/S0092-8674(24)00835-3

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