Comment

Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 12:32pm

For the first two decades after its discovery, most of the research has been centered on the core oscillator. it 's now found that the kinases, previously thought to be just output components, are actually part of the whole clock.

The core oscillator is often thought of as the 'gears' of the circadian clock and the kinases as the 'hands', with both required to tell the right time. What this study shows is how they're both needed – and how closely linked the inputs and outputs of the clock are.

If you don't have both hands they don't set time correctly because one of them is a stabilizer and one a perturber to the resetting signal, and you need both."

To put it another way, in retrieving information from the clock, the kinases also interfere with it. It was also shown that two kinases are needed to properly respond to a 'reset' signal, as might happen when we move through time zones.

Now that this method of real-time monitoring has been established, it can be used to better understand how our own internal circadian rhythms work, and how their timekeeping has an effect on the rest of our bodies.

https://www.pnas.org/doi/10.1073/pnas.2221453120

Part 2

Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 12:29pm

Researchers Studied a Circadian Clock in Real Time in a First For Science

We all have a built-in clock telling us when it's time to eat, time to sleep, and time to get up and do something with the day. Many organisms do, in fact, which is why it's such an important area of research for scientists.

Now the circadian clock and its responses to environmental cues has been studied in a way that has never been done before. Scientists were able to track the clock and its functions in real time, using a tiny aquatic organism called a cyanobacterium (Synechococcus elongatus). Given its clock works in a similar way to ours, it can tell us a thing or two about our own daily rhythms.

The team looked at the cyanobacterium's core oscillator – a nanomachine powered by three proteins that acts as a time regulator – studying the ways its output acts as a signal for timekeeping. The core 'oscillates' in response to different signal molecules binding to it throughout the day, resulting in the rhythmic expression of hundreds of genes within the cyanobacteria.

The new study analyzes how these interactions change when the cyanobacterium's clock 'resets' at the molecular level, something that could be compared to jet lag or daylight saving time adjustments for humans.

The research builds on an in vitro clock some members of the team had previously developed, one that could operate inside a test tube. Through new advancements in the way the clock is monitored and run, the team was able to get real-time readings as the timing settings were adjusted and responded to.

This revealed several new insights, including the fact enzymes known as kinases that mediate genetic expression are more closely related to the clock function than previously thought.

Part 1

Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 10:49am

In recent years, researchers have focused on this complex diplomacy between gut microflora, the immune system, and neurological functioning in an attempt to understand why areas of the brain degenerate and give rise to the symptoms of memory loss and cognitive decline we recognize as Alzheimer's disease.

Observational studies revealed a reduction in the diversity of gut microbes in individuals diagnosed with the condition, while laboratory analyses showed gut bacteria can release chemicals that could induce damaging inflammatory signals in the brain.

Complicating matters is a gene involved in the movement of fats through the blood known as apolipoprotein E (APOE). Of the three versions found in humans, a variant known as E4 appears to be a genetic risk for Alzheimer's. Why this is the case isn't clear, though there's good reason to suspect that having at least one copy of APOE E4 might hold some sway over the composition of our microbial citizens.

This latest exploration of the connections between microbes, APOE E4, and Alzheimer's provides even more compelling evidence of a mechanism at work in the gut.

An initial search of bacterial genes that could be associated with Alzheimer's revealed 20 genera suspected of playing some kind of role in the disease's development. A second hunt through a more constrained sample produced a slightly more certain 10 genera – six of which were fewer among diagnosed patients, and the remaining four being more common.

Of those 10 bacteria genera, four seemed to have a relationship with an APOE allele that is thought to raise the risk of Alzheimer's disease.

One example genus is the Actinobacterium Collinsella, which isn't only associated with Alzheimer's and the APOE variant but rheumatoid arthritis, atherosclerosis, and Type-2 diabetes as well.

The researchers suspect Collinsella's ability to promote the expression of inflammatory messenger hormones, together with its knack for making the gut more permeable, could play a role in exacerbating – if not triggering – neurological damage.

Elevated cholesterol and low-density lipoprotein (LDL) levels found in healthy adults with high numbers of Collinsella further show some link between microbes, fat metabolism, and neurodegeneration.

This is just one avenue for exploration; the research also uncovered 'protective' bacterial groups that could counter inflammation.

https://www.nature.com/articles/s41598-023-31730-5

Part 2

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Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 10:43am

Study Pinpoints Specific Gut Bacteria Linked to Alzheimer's

Tensions between the brain, the gut, and the makeup of its microbial inhabitants appear to play a critical role in the development of neurodegenerative conditions. While evidence favoring a link between the microbiota-gut-brain axis (MGBA) and Alzheimer's disease continues to grow, the exact mechanism behind the relationship is still poorly understood.

The puzzle pieces have so far been frustratingly incoherent, involving seemingly unrelated factors as tangled proteins inside nervous tissue to suspect gut microbes to subtle differences in fat-transporting molecules.

Using the largest ever genome-wide association study of human gut microflora, a team of researchers from the US sought out a more explicit relationship between Alzheimer's disease and the mix of organisms living inside the digestive system.

Their analysis uncovered not only a genetic connection between different genera of gut bacteria and a diagnosis of Alzheimer's but also a link between the microbes and a genetic risk factor for the neurodegenerative disorder.

The study further emphasizes the interplay of genetic factors and inflammatory gut microflora in healthy brain function.

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Early in our development, our bodies are colonized by an assortment of bacteria, fungi, and viruses that strike a tentative truce with the immune system. For the most part, this arrangement is mutually beneficial. The microbes get a place to live, and we get a front-line defense of tiny occupants willing to protect their home.

That's not to say the balance is always a harmonious one. Shifts in our immune system can give some species an advantage over others. Likewise, changes in the makeup of microbes – by way of shifts in our diet, for example – can profoundly affect the body's functioning. For better and worse.

The tug-of-war between our microbial census and general health can ripple throughout the body in less than predictable ways, sowing confusion in how distant tissues identify friend and foe.

Part 1

Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 10:15am

Lithium in Drinking Water Identified as Potential Risk Factor For Autism

Scientists have identified a link between lithium levels in a Denmark's water supply and an increased chance of children later receiving an autism diagnosis.

While the study of 52,706 kids isn't enough to prove that lithium is directly causing autism, the possibility is worthy of further investigation.

A naturally occurring element and a medication commonly used to treat mood disorders, lithium has previously been associated with miscarriages and cardiac malformations in newborns. This is the first time an association has been made with autism spectrum disorder ( ASD).

"In this Danish nationwide population-based case-control study, the study team found that maternal exposure to higher levels of residential lithium in drinking water during pregnancy was associated with a moderate increase in ASD risk in the offspring," write the researchers in their published paper.

"The findings remained robust after adjusting for several maternal neighborhood socioeconomic factors and air pollution exposures."

https://jamanetwork.com/journals/jamapediatrics/article-abstract/28...

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Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 8:55am

Quantum tunnelling reactions play an important role in chemistry when classical pathways are energetically forbidden, be it in gas-phase reactions, surface diffusion or liquid-phase chemistry. In general, such tunnelling reactions are challenging to calculate theoretically, given the high dimensionality of the quantum dynamics, and also very difficult to identify experimentally. Hydrogenic systems, however, allow for accurate first-principles calculations. In this way the rate of the gas-phase proton-transfer tunnelling reaction of hydrogen molecules with deuterium anions, H₂ + D⁻ → H⁻ + HD, has been calculated, but has so far lacked experimental verification. Here we present high-sensitivity measurements of the reaction rate carried out in a cryogenic 22-pole ion trap. We observe an extremely low rate constant of (5.2 ± 1.6) × 10⁻²⁰ cm³ s⁻¹. This measured value agrees with quantum tunnelling calculations, serving as a benchmark for molecular theory and advancing the understanding of fundamental collision processes. A deviation of the reaction rate from linear scaling, which is observed at high H₂ densities, can be traced back to previously unobserved heating dynamics in radiofrequency ion traps.

https://www.nature.com/articles/s41586-023-05727-z

Comment by Dr. Krishna Kumari Challa on April 9, 2023 at 8:49am

Bizarre Quantum Tunneling Observation Throws Out All the Rules

The strange phenomenon of quantum tunneling has been observed in a chemical reaction that defies classical physics

A chemical reaction is a bit like traveling from Vienna to Venice: your destination might be downhill, but to get there, you’ll need to cross the Alps. You can think of the energy changes molecules must go through as a landscape. Between the start and end of a reaction, this terrain can sometimes be so hilly that otherwise favorable reactions don’t happen at all if molecules lack the energy to make it over the bumps. Yet in some of these cases, such reactions do happen, thanks to quantum tunneling, which allows particles to occasionally bore through energy barriers they’d never be able to climb. This bizarre behavior is forbidden in traditional physics but allowed under the wild rules of quantum mechanics.

Now, in a new study published in Nature, scientists have managed to spot quantum tunneling in what classical physics would deem an impossible reaction between hydrogen molecules and deuterium ions—heavy, charged versions of hydrogen. This is the first time that researchers have managed to experimentally confirm a theoretical prediction about the rate of tunneling in a reaction involving ions. “Quantum mechanics in theory should be able to predict this [rate] very well,” says physicist Stephan Schlemmer of the University of Cologne in Germany, who was not involved in the study. “But nobody was sure whether this was really true.”

https://www.scientificamerican.com/article/bizarre-quantum-tunnelin...

https://www.nature.com/articles/s41586-023-05727-z

Comment by Dr. Krishna Kumari Challa on April 8, 2023 at 11:48am

In some cases, COVID-19 in pregnancy could harm the fetal brain

It's highly unlikely, but COVID-19 can be transmitted from mother to baby through the placenta, causing injury to the developing fetus' brain, a new study finds.

Researchers shared two unusual cases among hundreds of pregnant and delivering mothers they saw who were infected with COVID.

In both cases, the infants tested negative for COVID at birth, but had significantly elevated virus antibodies in their blood. This suggested that the antibodies had crossed the placenta or that the virus had passed to the baby and the immune response was the infant's.

Both infants had seizures, small head sizes and developmental delays. One died at 13 months.

Many women are affected by COVID-19 during pregnancy, but to see these kinds of problems in their infants at birth was clearly unusual.

Researchers are trying to understand what made these two pregnancies different, so they can direct research towards protecting vulnerable babies.

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The authors noted that early in the pandemic they observed transient lung disease and sometimes blood pressure issues among newborns born to mothers with COVID but who themselves had tested negative at birth.

This hinted at infection, the research authors said. It was unclear, however, whether the problems were caused by inflammatory placental cytokines or whether the virus had crossed the placenta and injured the baby. encephalopathy [brain damage caused by decreased blood flow].

But it wasn't lack of blood flow to the placenta that caused this. As best we can tell, it was the viral infection.

Analysis of both placentas clearly demonstrated severe inflammatory changes in each placenta, the authors said. The researchers were also struck by the absence of a critical placental hormone, human chorionic gonadotrophin. This hormone is essential for all fetal development, especially for brain development.

The authors noted that in both cases, the mothers contracted the infection in their second trimesters. Although they later cleared it, one had a repeat infection in her third trimester. This suggested an unusual maternal and/or fetal immune response to the virus.

 The U.S. Centers for Disease Control and Prevention has more on COVID-19 in pregnancy.

Merline Benny et al, Maternal SARS-CoV-2, Placental Changes and Brain Injury in 2 Neonates, Pediatrics (2023). DOI: 10.1542/peds.2022-058271

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Comment by Dr. Krishna Kumari Challa on April 8, 2023 at 11:30am

Scientists discover a way Earth's atmosphere cleans itself

Human activities emit many kinds of pollutants into the air, and without a molecule called hydroxide (OH), many of these pollutants would keep aggregating in the atmosphere.

How OH itself forms in the atmosphere was viewed as a complete story, but in new research published in Proceedings of the National Academy of Sciences, a research team  reports that a strong electric field that exists at the surface between airborne water droplets and the surrounding air can create OH by a previously unknown mechanism.

It's a finding that stands to reshape how scientists understand how the air clears itself of things like human-emitted pollutants and greenhouse gasses which OH can react with and eliminate. You need OH to oxidize hydrocarbons, otherwise they would build up in the atmosphere indefinitely.

OH is a key player in the story of atmospheric chemistry. It initiates the reactions that break down airborne pollutants and helps to remove noxious chemicals such as sulfur dioxide and nitric oxide, which are poisonous gases, from the atmosphere.

Thus, having a full understanding of its sources and sinks is key to understanding and mitigating air pollution.

Kangwei Li et al, Spontaneous dark formation of OH radicals at the interface of aqueous atmospheric droplets, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2220228120

Comment by Dr. Krishna Kumari Challa on April 8, 2023 at 11:21am

Geologists find evidence of dual mass extinctions 260 million years ago

Long before dinosaurs, Earth was dominated by animals that were in many ways even more incredible.

Carnivores such as Titanophoneus, or "titanic murderer," stalked enormous armored reptiles the size of buffalo.

Many of these animals died out in a mass extinction during the Capitanian Age approximately 260 million years ago.

Now an international team of researchers says evidence suggests this mass extinction was not a single event but two, separated by nearly 3 million years. Both were caused by the same culprit: massive volcanic eruptions.

By studying uranium isotope profiles of marine samples collected in the South China Sea, scientists identified two "pulses" in which the oceans became deprived of life-giving oxygen.

In a study published in the journal Earth and Planetary Science Letters, researchers say their analysis provides evidence that the oxygen-deprived oceans precipitated two mass extinctions around 259 million and 262 million years ago during the Middle Permian Period.

By studying these ancient extinctions, researchers can better predict how modern-day global warming could affect the ocean's food chain.

 Huyue Song et al, Global oceanic anoxia linked with the Capitanian (Middle Permian) marine mass extinction, Earth and Planetary Science Letters (2023). DOI: 10.1016/j.epsl.2023.118128

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