Comment

Comment by Dr. Krishna Kumari Challa on September 27, 2022 at 8:20am

New study shows transmission of epigenetic memory across multiple generations

Without altering the genetic code in the DNA, epigenetic modifications can change how genes are expressed, affecting an organism's health and development. The once radical idea that such changes in gene expression can be inherited now has a growing body of evidence behind it, but the mechanisms involved remain poorly understood.

A new study by researchers  shows how a common type of epigenetic modification can be transmitted via sperm not only from parents to offspring, but to the next generation ("grandoffspring") as well. This is called "transgenerational epigenetic inheritance," and it may explain how a person's health and development could be influenced by the experiences of his or her parents and grandparents.

The study, published the week of September 26 in the Proceedings of the National Academy of Sciences (PNAS), focused on a particular modification of a histone protein that changes the way DNA is packaged in the chromosomes. This widely studied epigenetic mark (called H3K27me3) is known to turn off or "repress" the affected genes and is found in all multicellular animals—from humans to the nematode worm C. elegans used in this study.

These results establish a cause-and-effect relationship between sperm-transmitted histone marks and gene expression and development in offspring and grandoffspring.

Sperm-inherited H3K27me3 epialleles are transmitted transgenerationally in cis, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2209471119

Comment by Dr. Krishna Kumari Challa on September 27, 2022 at 8:15am

Disarming the immune system's lethal lung response

Neutrophils, the most abundant type of white blood cell, are the body's first line of defense against infection. Foreign pathogens can stress the body and activate neutrophils. When activated, neutrophils employ various weapons to protect the body. But if overactivated, these weapons can damage the body's own tissues. Lung tissue is saturated with blood vessels, making them very susceptible to neutrophil attacks. If severe enough, acute lung injuries can lead to acute respiratory distress syndrome (ARDS), the leading cause of death due to COVID-19.

Researchers have found a drug candidate that can prevent lethal lung inflammation in mice by inhibiting a protein called PTP1B. Their discovery may help develop better treatments for severe inflammatory conditions like sepsis and COVID-19.

They investigated whether using a PTP1B inhibitor drug candidate could dampen the lethal consequences of overactive neutrophils in mice. They found that pretreating mice with the PTP1B inhibitor reduced lung tissue damage. When untreated, less than half of the mice survived acute lung injuries and ARDS. But when pretreated, they all survived.

The researchers exploited a natural process, called neutrophil aging, that the body uses to control the immune cell's lifespan. As they age, neutrophils become less dangerous. They discovered PTP1B inhibition speeds up neutrophil aging. An aged neutrophil is like a soldier without a weapon. So regardless of how many neutrophils flood an area, they won't be able to do serious damage.

Dongyan Song et al, PTP1B inhibitors protect against acute lung injury and regulate CXCR4 signaling in neutrophils, JCI Insight (2022). DOI: 10.1172/jci.insight.158199

Comment by Dr. Krishna Kumari Challa on September 24, 2022 at 11:07am

Scientists use modified silk proteins to create new nonstick surfaces

Researchers at Tufts University have developed a method to make silk-based materials that refuse to stick to water, or almost anything else containing water for that matter. In fact, the modified silk, which can be molded into forms like plastic, or coated onto surfaces as a film, has non-stick properties that surpass those of nonstick surfaces typically used on cookware, and it could see applications that extend into a wide range of consumer products, as well as medicine.

Comment by Dr. Krishna Kumari Challa on September 24, 2022 at 10:23am

Graphic on NASA's DART mission to crash a small spacecraft into a mini-asteroid to change its trajectory as a test for any potentially dangerous asteroids in the future.

Comment by Dr. Krishna Kumari Challa on September 24, 2022 at 10:22am

NASA gears up to deflect asteroid, in key test of planetary defense

NASA on Monday will attempt a feat humanity has never before accomplished: deliberately smacking a spacecraft into an asteroid to slightly deflect its orbit, in a key test of our ability to stop cosmic objects from devastating life on Earth.

The Double Asteroid Redirection Test (DART) spaceship launched from California last November and is fast approaching its target, which it will strike at roughly 14,000 miles per hour (23,000 kph).

To be sure, neither the asteroid moonlet Dimorphos, nor the big brother it orbits, called Didymos, pose any threat as the pair loop the Sun, passing some seven million miles from Earth at nearest approach.

But the experiment is one NASA has deemed important to carry out before an actual need is discovered.

If all goes to plan, impact between the car-sized spacecraft, and the 530-foot (160 meters, or two Statues of Liberty) asteroid should take place on September 26 

By striking Dimorphos head on, NASA hopes to push it into a smaller orbit, shaving ten minutes off the time it takes to encircle Didymos, which is currently 11 hours and 55 minutes—a change that will be detected by ground telescopes in the days that follow.

The proof-of-concept experiment will make a reality what has before only been attempted in science fiction

Comment by Dr. Krishna Kumari Challa on September 23, 2022 at 11:48am

Discovery explains cancer chemotherapy resistance, offers solution

Researchers have uncovered a novel pathway that explains how cancer cells become resistant to chemotherapies, which in turn offers a potential solution for preventing chemo-resistance.

Experimental DNA fibers with fluorescence were used to reveal the speed of DNA replication forks.

The research describes for the first time how a type of enzyme -- previously known for its roles in DNA repair -- prevents DNA damage in cancer cells, making them tolerant to chemotherapy drugs. It provides scientists tools to manipulate and then break chemo-resistance in cancer cells. 

Many anti-cancer drugs work by creating blocks on the DNA of cancer cells as they replicate. During replication, DNA strands entwined in a double helix separate into two individual strands so each strand can be copied, eventually leading to two new double helixes. The junction where this separation and copying occurs is called a replication fork, which unzips down the double helix.

If these replication forks were cars on a road, chemotherapy drugs can be imagined as obstacles that interfere with the flow of the cars, thus stopping replication and breaking DNA. But cancer cells have a way of slowing down these forks, which allows them to avoid such collisions and protect their DNA, leading to drug tolerance.

This study reports, for the first time, how a kinase (enzyme) called DNA-PKcs acts as a sensor when a fork is stressed due to blocks, and promotes slowing of the fork and chemo-resistance. DNA-PKcs has been known for its role in DNA repair related to immune system antibody generation and resistance to radiation. But this is the first time the kinase has been associated with slowing a replication fork, a process called fork reversal.

The results open the door to new cancer treatments, as DNA-PKcs inhibitors already exist and are being used for clinical trials in tandem with radiation therapies.

Diego Dibitetto, Shannon Marshall, Andrea Sanchi, Martin Liptay, Jumana Badar, Massimo Lopes, Sven Rottenberg, Marcus B. Smolka. DNA-PKcs promotes fork reversal and chemoresistance. Molecular Cell, 2022; DOI: 10.1016/j.molcel.2022.08.028

Comment by Dr. Krishna Kumari Challa on September 23, 2022 at 6:48am

More than one-tenth of the world's terrestrial genetic diversity may already be lost, study says

Climate change and habitat destruction may have already caused the loss of more than one-tenth of the world's terrestrial genetic diversity, according to new research published in Science. This means that it may already be too late to meet the United Nations' proposed target, announced last year, of protecting 90 percent of genetic diversity for every species by 2030, and that we have to act fast to prevent further losses.

Several hundred species of animals and plants have gone extinct in the industrialized age and human activity has impacted or shrunk half of Earth's ecosystems, affecting millions of species. The partial loss of geographic range diminishes population size and can geographically prevent populations of the same species from interacting with each other. This has serious implications for an animal or plant's genetic richness and their ability to meet the coming challenges of climate change.

When you take away or fundamentally alter swaths of a species' habitat, you restrict the genetic richness available to help those plants and animals adapt to shifting conditions. Until recently, this important component has been overlooked when setting goals for preserving biodiversity, but without a diverse pool of natural genetic mutations on which to draw, species will be limited in their ability to survive alterations to their geographic range.

In popular culture, mutations convey super powers that defy the laws of physics. But in reality, mutations represent small, random natural variations in the genetic code that could positively or negatively affect an individual organism's ability to survive and reproduce, passing down the positive traits down to future generations.

As a result, the greater the pool of mutations upon which a species is able to draw, the greater the chances of stumbling upon that lucky blend that will help a species thrive despite the pressures created by habitat loss, as well as shifting temperature and precipitation patterns.

Moises Exposito-Alonso, Genetic diversity loss in the Anthropocene, Science (2022). DOI: 10.1126/science.abn5642. www.science.org/doi/10.1126/science.abn5642

Comment by Dr. Krishna Kumari Challa on September 23, 2022 at 6:25am

Charging cars at home at night is not the way to go: study 

The vast majority of electric vehicle owners charge their cars at home in the evening or overnight. We're doing it wrong, according to a new  study.

This  stresses any region's electric grid and this will become a tremendous problem by 2035 from growing EV ownership. In a little over a decade, researchers found, rapid EV growth alone could increase peak electricity demand by up to 25 percent, assuming a continued dominance of residential, nighttime charging.

To limit the high costs of all that new capacity for generating and storing electricity, the researchers say, drivers should move to daytime charging at work or public charging stations, which would also reduce greenhouse gas emissions. This finding has policy and investment implications for the region and its utilities.

 Siobhan Powell, Charging infrastructure access and operation to reduce the grid impacts of deep electric vehicle adoption, Nature Energy (2022). DOI: 10.1038/s41560-022-01105-7. www.nature.com/articles/s41560-022-01105-7

Comment by Dr. Krishna Kumari Challa on September 22, 2022 at 9:55am

A New Treatment Shown to Have a 'Dramatic' Effect on Kids With Eczema

Eczema (or atopic dermatitis) affects millions of people, particularly children under the age of six.

The chronic inflammatory skin disorder causes the skin to go red and dry and to start oozing and itching, making life very uncomfortable.

There's currently no cure for the condition, just ways of managing it – but an existing drug is incredibly effective at reducing the signs and symptoms of eczema in kids under six with moderate to severe cases of the disorder. It's the first time a complex biologic drug like this has been tested on this age group. The drug in question is dupilumab. In a new study, 162 North American and European kids between the ages of 6 months and 6 years with moderate-to-severe eczema were given dupilumab or a placebo across the course of 16 weeks. More than half of the kids given the drug showed a 75 percent reduction in symptom severity. Itchiness was significantly reduced, and the kids could sleep much better.

Dupilumab targets an important immune inflammation pathway in allergies and is already used to treat eczema in older children and adults, as well as asthma, nasal polyps, and other allergy-mediated problems.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(22)01539-2/fulltext

**

Comment by Dr. Krishna Kumari Challa on September 22, 2022 at 9:21am

Chemical cocktail in skin summons disease-spreading mosquitoes

Mosquitoes that spread Zika, dengue and yellow fever are guided toward their victims by a scent from human skin. The exact composition of that scent has not been identified until now.

A research team discovered that the combination of carbon dioxide plus two chemicals, 2-ketoglutaric and lactic acids, elicits a scent that causes a mosquito to locate and land on its victim. This chemical cocktail also encourages probing, the use of piercing mouthparts to find blood. This chemical mixture appears to specifically attract female Aedes aegypti mosquitoes, vectors of Zika as well as chikungunya, dengue, and yellow fever viruses. This mosquito originated in Africa, but has spread to tropical and subtropical regions worldwide, including the U.S. This new research finding, and how the team discovered it, is detailed in the journal Scientific Reports. Though others have identified compounds that attract mosquitoes, many of them don't elicit a strong, rapid effect. This one does.

Mosquitoes use a variety of cues to locate their victims, including carbon dioxide, sight, temperature, and humidity. However, recent research shows skin odors are even more important for pinpointing a biting site.

Scientific Reports (2022). DOI: 10.1038/s41598-022-19254-w

• ‹ Previous
• 1
• …
• 464
• 465
• 466
• 467
• 468
• …
• 1081
• Next ›
• Page