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Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:21am

Why do some men not produce sperm? Scientists uncover one underlying reason for male infertility

Millions of couples worldwide experience infertility with half of the cases originating in men. For 10% of infertile males, little or no sperm are produced. Now, new research is shedding light on what may be going wrong in the process of sperm formation, leading to potential theories on possible treatments.

In most sexually-reproducing species, including humans, a critical protein structure resembling a lattice-like bridge needs to be built properly to produce sperm and egg cells. The team  discovered that in mice, changing a single and very specific point in this bridge caused it to collapse, leading to infertility and thus providing insight into human infertility in males due to similar problems with meiosis.

Part 1

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:03am

Microbiome facts
There are trillions of microbes living inside and on the surface of your body; together they are called the microbiome and they are vital to your health and fighting disease.
Since the microbiome was first recognized in the late 1990s, scientists have identified more than 2,000 microbial species from the largest microbiome, in the gut.
The skin, bladder and genitals also harbor microbiome populations.
Your gut microbiome composition is unique to you and effects your metabolism, gastrointestinal tract, brain, and immune system.
In a healthy person, the symbiotic and pathogenic microbes work in balance.
Imbalances between symbiotic (benefiting you and the microbes) and pathogenic (disease-causing) microbes, known as dysbiosis, disrupt the microbes, making people more susceptible to conditions such as inflammatory bowel disease (IBD) and Clostridioides difficile infection, which causes severe diarrhea and inflammation of the colon or colitis.
There is hope that we may soon be on the cusp of a new era of health care that nurtures and tweaks the microbiome to optimize human health.

Disease-specific loss of microbial cross-feeding interactions in the human gut, Nature Communications (2023). DOI: 10.1038/s41467-023-42112-w

Part 2

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:02am

Deep dive into the gut unlocks new disease treatments

The more diverse species in your gut, the better it is for your health. Now an international team has found a way to determine which species are important and how they interact to create a healthy microbiome.

Understanding these relationships opens the door to a new world of medical opportunities for conditions from inflammatory bowel disease to infections, autoimmune diseases and cancers.

There are roughly 1,000 different bacterial species in a healthy gut—it's a microscopic multicultural community with over a trillion individual members.

Bacteria in our microbiomes exist as communities that rely on each other to produce and share key nutrients between them.

Researchers have developed a new computational way to understand these dependencies and their role in shaping human microbiome. This new method unlocks our understanding of the gut microbiome and provides a foundation for new treatment options that selectively remodel microbial communities.

For example, in Crohn's Disease, the team confirmed the importance of hydrogen sulfide. They discovered that the most likely cause is loss of bacteria that use hydrogen sulfide, not an increase in species producing it, as was previously thought. 

This is a significant step in the development of complex microbial therapies. This approach allows us to identify and rank the key interactions between bacteria and use this knowledge to predict targeted ways to change the community.

Part 1

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 9:46am

New study shows Hunga-Tonga Hunga-Ha'apai eruption depleted ozone layer

A large team of atmospheric specialists has found that when the Hunga-Tonga Hunga-Ha'apai volcano erupted last year, it took part of the ozone layer with it. Their findings are published in the journal Science.

Prior research has shown that the Hunga-Tonga Hunga-Ha'apai eruption was one of the more powerful explosions ever recorded. It was also unique in that instead of spewing just volcanic material, dirt and rocks, it also sent a very large amount of ocean water into the atmosphere. In this new effort, the research team have found that all that saltwater reacting with other chemicals in the atmosphere, resulted in breaking down O₃ in the ozone layer.

To learn more about the impact of the eruption, the researchers sent balloons with sensors into the atmosphere from nearby Réunion Island just five days after the volcano erupted. In studying the data from the sensors, the researchers found that ozone levels in the plume were approximately 30% below normal levels.

As the balloons continued to monitor the plume as it floated across the Indian and then Pacific Ocean, they found depletion totals of approximately 5%. The depletion, they found was due to ocean water reacting with molecules in the atmosphere that contained chlorine, leading to a breakdown of ozone—in amounts that had never been seen before in such a short time.

 Stephanie Evan et al, Rapid ozone depletion after humidification of the stratosphere by the Hunga Tonga Eruption, Science (2023). DOI: 10.1126/science.adg2551

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 9:33am

10 billion snow crabs starved to death in the Bering Sea because ...

A team of marine biologists has solved the mystery of why approximately 10 billion snow crabs vanished from the Bering Sea back in 2018/2019—the water there was too warm for them!

In their study, reported in the journal Science, the group used data from previous studies on the way snow crabs respond to warmer temperatures to solve the mystery.

Snow crabs are relatively small crabs, that, despite their name, are not white—they are red, like lobsters. They live on the ocean floor in shallow areas and have been consumed as a seafood delicacy for many years.

Alaskan fishermen (and scientists) first noticed a dramatic decline in their numbers back in 2021. Then, due to the pandemic, fishing and studying of the crabs was put on hiatus for a year. The full extent of the crab disappearance was only observed earlier in 2023—over 10 billion were missing. Upon discovering this alarming decline, a research team set to work to figure out what happened.

The team started by scouting nearby areas, hoping that the crabs had simply moved to another location, but no sign of them could be found. Next, noting that the area had experienced a heat wave prior to, and during, the crab disappearance they turned to the results of a prior study that had found that when water temperatures increase, energy requirements for the crabs increase. The researchers found that if water temperatures increased by just 3°C, the caloric needs of the crabs doubled.

Records showed that during the heat wave, water temperatures had risen 3°C, which meant the crabs would have needed twice as much food to sustain themselves. The research team also found that just prior to the heat wave, the crab population had risen dramatically, meaning that there had been a large increase in competition for food. And that, the researchers conclude, led the crabs to starve to death.

Need we give more evidence to  what might happen to the heat sensitive creatures during  global warming?

Cody S. Szuwalski et al, The collapse of eastern Bering Sea snow crab, Science (2023). DOI: 10.1126/science.adf6035

Gordon H. Kruse, Are crabs in hot water?, Science (2023). DOI: 10.1126/science.adk7565

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 9:16am

Evidence of Earth's core leaking found 

A  team of geochemists has found evidence of high levels of helium-3 in rocks on Baffin Island—possible evidence that the Earth's core is leaking. 

Prior researchers found trace elements of helium-3 in lava flows on Baffin Island, hinting at the possibility that the Earth's core might be leaking. This is because it is an ancient isotope—it was prevalent during the time when Earth was forming and became trapped in the core. But because of its nature, helium-3 that makes its way to the surface soon escapes into the atmosphere and disappears into space. Thus, helium-3 is rare. If it is found on the surface, the odds are high that it made its way out of the core.

Intrigued by the possibility that the Earth's core might be leaking, the research team ventured to Baffin Island and began testing multiple lava flows. They found much higher levels of helium-3 than observed in prior research efforts—higher than anywhere else on Earth. They also found high ratios of helium-3 to helium-4 (a common isotope)—the highest that have ever been measured in terrestrial rock. Such high ratios, the researchers suggest, is another factor suggesting that the helium-3 is leaking from the core.

The research team notes that finding such high levels of helium-3 at a terrestrial site is a big deal, because if it can be proved that the material is indeed leaking from the core, it will provide scientists with a way to study core material, which has never been done before. That could reveal more about the core than previously thought possible. They note that if the helium-3 is coming from the core, then the other material around it should be as well, offering further physical examples of core material.

F. Horton et al, Highest terrestrial 3He/4He credibly from the core, Nature (2023). DOI: 10.1038/s41586-023-06590-8

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 11:37am

In particular, just before ovulation, when the hormones 17β-estradiol and luteinizing hormone rise, the brains of the participants showed white matter changes suggesting faster information transfer.

Follicle-stimulating hormone, which rises before ovulation, and helps stimulate the ovary follicles, was associated with thicker gray matter.

Progesterone, which rises after ovulation, was associated with increased tissue and decreased cerebrospinal fluid volume.

What this means for the person driving the brain is unknown, but the research lays the groundwork for future studies, and perhaps understanding the causes of unusual but severe period-related mental health problems.

These findings may have implications for hormone-driven alterations in behavior and cognition," the researchers write.

https://www.biorxiv.org/content/10.1101/2023.10.09.561616v1

Part 2

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 11:36am

Scientists Show Structural, Brain-Wide Changes During Menstruation

The constant ebb and flow of hormones that guide the menstrual cycle don't just affect reproductive anatomy. They also reshape the brain, and a new study has given us insight into how this happens.

A team of researchers tracked 30 women who menstruate over their cycles, documenting in detail the structural changes that take place in the brain as hormonal profiles fluctuate.

The results, which are yet to be peer-reviewed but can be found on preprint server bioRxiv, suggest that structural changes in the brain during menstruation may not be limited to those regions associated with the menstrual cycle.

These results are the first to report simultaneous brain-wide changes in human white matter microstructure and cortical thickness coinciding with menstrual cycle-driven hormone rhythms," the researchers write.

Strong brain-hormone interaction effects may not be limited to classically known hypothalamic-pituitary-gonadal-axis (HPG-axis) receptor-dense regions.

Cyclic fluctuations in HPG-axis hormones exert powerful behavioural, structural, and functional effects through actions on the mammalian central nervous system.

The microstructure of white matter – the fatty network of neuronal fibers that transfer information between regions of gray matter – has been found to change with hormonal shifts, including puberty, oral contraception use, gender-affirming hormone therapy, and post-menopausal estrogen therapy.

To address the menstruation gap in our understanding, the team took MRI scans of their subjects during three menstrual phases: menses, ovulation, and mid-luteal. At the time of each of these scans, the researchers also measured the participants' hormone levels.

The results showed that, as hormones fluctuate, gray and white matter volumes change too, as does the volume of cerebrospinal fluid.

Part 1

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:46am

Gray whales make the longest migration of any mammal on Earth, traveling more than 12,000 miles every year from their foraging grounds in the Arctic, where they spend the summers, to their breeding grounds in the warm, shallow lagoons of Mexico's Baja Peninsula, where they spend the winters.

While in the Arctic, the gray whales feed on amphipod crustaceans. Amphipods in turn feed on algae, which grows on the underside of sea ice.

With less ice, you get less algae, which is worse for the gray whale prey. When there are sudden declines in the quality of prey, the population of gray whales is significantly affected.

In other words, the melting sea ice disrupts the entire food chain.

The decrease in available food can cause skinnier or malnourished whales, as well as lower birth rates.

Even highly mobile, long-lived species such as gray whales are sensitive to climate change impacts.

Part 2

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https://www.businessinsider.in/science/news/gray-whales-have-been-m...

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:43am

Mystery of Dead Whales Washing Up on US Coast May Be Solved

Gray whales have been washing up dead on the Pacific coast at an alarming rate since 2019, and scientists think they might finally know why.

The gray whale strandings from Mexico all the way to Alaska have been declared an "unusual mortality event," or a significant die-off of a species that is unexplained and requires a quick response.

Two other mass die-offs of gray whales occurred in the 1980s and 1990s, though those only lasted a couple of years; the latest is still ongoing. The latest die-off has caused the North Pacific gray whale population to plummet from an estimated 27,000 in 2016 to 14,500 in 2023, according to the National Oceanic and Atmospheric Administration. For years, researchers could only guess what was killing the whales. NOAA has previously noted that emaciation had been observed in some of the dead whales, but not in others. But scientists at Oregon State University's Marine Mammal Institute now say there is strong evidence that the whale deaths are linked directly to sea ice melting in the Arctic, according to a study published recently in the journal Science.

The decrease in sea ice was also causing the gray whales' food supply to diminish.

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