Comment

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 10:19am

A new treatment for multidrug-resistant bacteria

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 10:14am

Near-universal T cell immunity towards a broad range of bacteria discovered

 Typically T cells of the immune system respond to a specific feature (antigen) of a microbe, thereby generating protective immunity. As reported in the journal Immunity, an international team of scientists have discovered an exception to this rule. Namely, a group of divergent bacterial pathogens, including pneumococci, all share a small highly conserved protein sequence, which is both presented and recognized by human T cells in a conserved population-wide manner.

The study set out to understand immune mechanisms that protect against pneumococcus, a bacterial pathobiont that can reside harmlessly in the upper respiratory mucosae but can also cause infectious disease, especially in infants and older adults, which can range from middle ear and sinus infections to pneumococcal pneumonia and invasive bloodstream infections.

The researchers identified a crucial fragment of the pneumococcal toxin pneumolysin that was commonly presented by a particular class of human antigen presenting molecules and recognized by T cells from most people who naturally develop specific immunity to pneumococcal proteins.

The study further found that the uniformly presented and broadly recognized bacterial protein fragment was not unique for the pneumococcal pneumolysin but was shared by a large family of bacterial so-called cholesterol dependent cytolysins (CDCs). These are produced by divergent bacterial pathogens mostly affecting humans and cause a range of respiratory, gastro-intestinal, or vaginal infectious diseases.

Jamie Rossjohn, CD4+ T cell-mediated recognition of a conserved cholesterol-dependent cytolysin epitope generates broad antibacterial immunity, Immunity (2023). DOI: 10.1016/j.immuni.2023.03.020. www.cell.comimmunity/fulltext/ … 1074-7613(23)00140-1

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 9:45am

Newly discovered electrical activity within cells could change the way researchers think about biological chemistry

The human body relies heavily on electrical charges. Lightning-like pulses of energy fly through the brain and nerves and most biological processes depend on electrical ions traveling across the membranes of each cell in our body.

These electrical signals are possible, in part, because of an imbalance in electrical charges that exists on either side of a cellular membrane. Until recently, researchers thought the membrane was an essential component to creating this imbalance. But that thought was turned on its head when researchers discovered that similar imbalanced electrical charges can exist between microdroplets of water and air.

Now, researchers have discovered that these types of electric fields also exist within and around another type of cellular structure called biological condensates. Like oil droplets floating in water, these structures exist because of differences in density. They form compartments inside the cell without needing the physical boundary of a membrane.

Inspired by previous research demonstrating that microdroplets of water interacting with air or solid surfaces create tiny electrical imbalances, the researchers decided to see if the same was true for small biological condensates. They also wanted to see if these imbalances sparked reactive oxygen, "redox," reactions like these other systems.

Appearing on April 28 in the journal Chem, their foundational discovery could change the way researchers think about biological chemistry. It could also provide a clue as to how the first life on Earth harnessed the energy needed to arise.

Yifan Dai et al, Interface of biomolecular condensates modulates redox reactions, Chem (2023). DOI: 10.1016/j.chempr.2023.04.001

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 9:38am

Scientists design new bio-inspired molecules to promote bone regeneration

People's ability to regenerate bones declines with age and is further decreased by diseases such as osteoporosis. To help the aging population, researchers are looking for new therapies that improve bone regeneration.

Now, an interdisciplinary team of researchers  developed novel bio-inspired molecules that enhance bone regeneration in mice. The results were published in the journal Biomaterials.

As people age, their ability to regenerate bones decreases. Fractures take longer to heal and diseases like osteoporosis only add to it. This represents a serious health challenge to the aging population and an increasing socioeconomic burden for the society. To help combat this issue, researchers are looking for new therapeutic approaches that can improve bone regeneration.

A team of scientists  used computer modeling and simulations to design novel bio-inspired molecules to enhance bone regeneration in mice. The new molecules can be incorporated into biomaterials and applied locally to bone defects. These new molecules are based on glycosaminoglycans, which are long-chained sugars such as hyaluronic acid or heparin.

 Gloria Ruiz-Gómez et al, Rational engineering of glycosaminoglycan-based Dickkopf-1 scavengers to improve bone regeneration, Biomaterials (2023). DOI: 10.1016/j.biomaterials.2023.122105

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 9:31am

If you are exceeding the ecological ceiling, then you're not sustainable from an environmental perspective. If you're below the social foundation, then you're not meeting basic human needs, and that can be frustrating from an equity point of view.

The team found that the majority of countries emit far more than their national ecosystem can handle in terms of carbon, but tend to operate close to their water supply limits.

Sometimes countries do not have much of a choice. Findings showed that 37% of countries do not have the ability to provide for their citizens in a safe and just way in terms of carbon sequestration, and 10% lack the ability to do that with regard to water.

While the socioeconomic status of countries is often related to how well they can provide for their citizens in a sustainable manner, it doesn't always work that way, the researchers said.

Despite the study's potentially bleak outlook, the researchers think their work offers a glimmer of hope in combating the environmental risks of human development. The team's results imply that many nations could secure the necessary resources they need to thrive at a much lower demand than current levels suggest.

One way to do this would be to adopt more renewable energy resources, introduce more plant-based diets into our food cycles, and change the way we produce certain goods and services to develop a sustainable circular economy instead of a linear one.

 Yazeed M. Aleissa et al, Possible but rare: Safe and just satisfaction of national human needs in terms of ecosystem services, One Earth (2023). DOI: 10.1016/j.oneear.2023.03.008

Part 2

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 9:29am

Study finds only 6% of nations provide for citizens in a just, sustainable manner

Researchers  have developed a framework for quantifying how well countries around the world are doing at providing adequate food, energy and water to their citizens without exceeding nature's capacity to meet those needs.

They found that only 6% of 178 countries provide for all their citizens in an ecologically sustainable way in both carbon sequestration and water consumption.

The study found that while 67% of nations operate safely and sustainably in regard to water use, only 9% do so in regard to carbon sequestration, or reducing their greenhouse gas emissions.

For a country to be self-sufficient, its population needs access to food, water and energy, resources that can often only be provided by the surrounding ecosystem. Yet because human activities tend to cause unintended side effects like global warming or ozone depletion, it's imperative that experts look for ways to develop society in an ecologically sustainable manner. At the same time, in order to be socially just, countries need to secure resources to meet the basic needs of all of its citizens.

Ideally, human activities should exist between the limits of a society's ecological ceiling and its social foundation, a boundary that describes the resources necessary to avoid critical human deprivation of food, water or energy.

Part 1

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 8:34am

MRI imaging method captures brain glucose metabolism without administering radioactive substances

Metabolic disorders play a central role in many common conditions, including Alzheimer's, depression, diabetes and cancer, which call for reliable as well as non-invasive diagnostic procedures. Until now, radioactive substances have been administered as part of the process of mapping glucose metabolism in the brain.

Now, a research team has developed a completely new magnetic resonance imaging (MRI) approach. Using a harmless glucose solution, the procedure generates reliable results and—in principle—can be used with all common MRI scanners. The findings from the study have just been published in the journal Nature Biomedical Engineering.

The study looked at—and has significantly enhanced—current diagnostic procedures for mapping brain glucose metabolism. The results were generated by measuring blood glucose levels and metabolic products in healthy subjects several times during a period of around 90 minutes. In contrast to existing procedures, the subjects did not receive radio-labeled glucose but a quantity of a harmless glucose solution equivalent to a can of a fizzy drink. As this substance does not produce a direct signal for the MR imaging method used, concentrations and metabolism of glucose were measured indirectly based on the drop in signal intensity for the product concerned.

The main advantage of this indirect method is that it can be used on other MR devices without any difficulties, because no additional hardware components are required, as is the case with other, comparable approaches.

 Petr Bednarik et al, 1H magnetic resonance spectroscopic imaging of deuterated glucose and of neurotransmitter metabolism at 7 T in the human brain, Nature Biomedical Engineering (2023). DOI: 10.1038/s41551-023-01035-z

Fabian Niess et al, Noninvasive 3-Dimensional 1H-Magnetic Resonance Spectroscopic Imaging of Human Brain Glucose and Neurotransmitter Metabolism Using Deuterium Labeling at 3T, Investigative Radiology (2023). DOI: 10.1097/RLI.0000000000000953

Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 8:26am

A neural circuit that suppresses male aggression when an opponent is physically advantaged

For decades, neuroscientists have been trying to understand the neural mechanisms underpinning different social behaviors, including aggression. Aggressive, violent, or confrontational behaviors are common among humans and many animal species, yet the neural processes supporting or suppressing these behaviors have not been fully unveiled yet.

Researchers recently unveiled an area in the hypothalamus, brain region influencing the nervous system and the release of hormones, that suppresses aggression in male mice when they are confronting a stronger or physically "superior" opponent. Their findings, published in Nature Neuroscience, shed some new light on the neural pathways modulating aggression in animals and potentially also humans.

Previously, scientists found that VMHvl is an essential region for generating aggression.

While conducting their studies, researchers realized that rostral (i.e., frontal) and caudal (i.e., posterior) parts of the MPOA, an area of the hypothalamus, responded differently while mice were socially interacting with each other. They found that the caudal MPOA tended to be more active during interactions between two males than during interactions between male and female mice.

When they manipulated the caudal MPOA, they found that aggression is strongly suppressed. They then considered the potential situation under which male aggression towards another male could be suppressed. This led them to discover that cMPOA cell activity increases when a male encounters a stronger opponent.

To conduct their recent experiments, the researchers used a combination of optogenetic and chemogenetic techniques. They recorded calcium activity in the mice's brain using fiber photometry, an optogenetic technique, and also collected patch clamp recordings in slices of the mouse brain.

Using optogenetic techniques, they also inhibited or activated cells in the cMPOA of living male mice and observed their resulting behaviour during social interactions. Interestingly, the inhibition of these cells appeared to increase the male mice's aggression towards other males, while activating them decreased the mice's aggressive behaviours.

These findings suggest that cMPOA cells naturally suppress aggression.

Overall, the findings gathered in this study suggest that the posterior part of the MPOA can significantly influence aggressive behaviour between male mice. Specifically, this area of the hypothalamus appears to reduce aggression towards a stronger male opponent, by suppressing activity in the VMHvl.

Dongyu Wei et al, A hypothalamic pathway that suppresses aggression toward superior opponents, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01297-5

**

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 12:03pm

Four different plastic models were used to study the role of the plastic particle' corona. The simulations showed that particles with a protein corona couldn't enter the barrier. However, those with a cholesterol corona could cross, even if they couldn't progress deeper into brain tissue.

The results raise the possibility that plastic can be transported across the membrane and into the brain tissue with the help of the right molecular cocktail. Knowing the fundamental mechanisms is an important first step in managing their harmful effects.

https://www.mdpi.com/2079-4991/13/8/1404

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 12:03pm

Plastic Particles Found in The Brains of Mice Just Two Hours After They Ate

Thanks to their flexibility, durability, and affordability, plastics have oozed their way into just about every aspect of our lives. When these items do eventually break down, the resulting micro- and nanoplastics (MNPs) can harm wildlife, the environment, and ourselves. MNPs have been found in blood, lungs, and placenta, and we know that they can get into our bodies through the food and liquids we consume.

A new study by a team of researchers from Austria, the US, Hungary, and the Netherlands has found MNPs can reach the brain a few hours after being eaten, possibly thanks to the way other chemicals stick to their surface.

Not only is the speed alarming, the very possibility of tiny polymers sliding into our nervous system raises some serious alarm bells.

In the brain, plastic particles could increase the risk of inflammation, neurological disorders or even neurodegenerative diseases such as Alzheimer's or Parkinson's.

In the study, tiny fragments of MNPs orally administered to mice were detectable in their brains in as little as two hours. But how do MNPs get through the blood-brain barrier, which is supposed to keep the brain safe?

As a system of blood vessels and tightly packed surface tissue, the blood-brain barrier helps shield our brains from potential threats by blocking the passage of toxins and other undesirables, while permitting more useful substances across. It stands to reason that plastic particles would count as a material to keep well and truly out of the brain's sensitive tissues.

With the help of computer models, scientists discovered that a certain surface structure (biomolecular corona) was crucial in enabling plastic particles to pass into the brain.

To verify that the particles truly can enter the brain, polystyrene (a common plastic used in food packaging) MNPs in three sizes (9.5, 1.14, and 0.293 micrometers) were labeled with fluorescent markers and pretreated in a mixture similar to digestive fluid before being fed to mice.

The researchers  found specific nanometer-sized green fluorescent signals in the brain tissue of MNP-exposed mice after only two hours!

Only 0.293 micrometer sized particles were able to be taken up from the gastrointestinal tract and to penetrate the blood brain barrier.

How these tiny, blanketed plastics cross cell barriers in the body is complicated and depends on factors like particle size, charge, and cell type.

Tinier plastic particles have a higher surface area-to-volume ratio, making them more reactive and potentially more hazardous than larger microplastics. This reactivity is thought to allow the small bits of plastic to gather other molecules around them, hugging them tight with molecular forces to form a durable cloak called a corona.

Part 1

• ‹ Previous
• 1
• …
• 177
• 178
• 179
• 180
• 181
• …
• 869
• Next ›
• Page