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Comment by Dr. Krishna Kumari Challa on December 18, 2023 at 11:14am

Kids with cats have more than double the risk of developing schizophrenia, researchers find

Researchers  have added to the growing body of evidence that cat ownership is a major risk factor for schizophrenia and quantified the risk at more than double.

In a paper, "Cat Ownership and Schizophrenia-Related Disorders and Psychotic-Like Experiences: A Systematic Review and Meta-Analysis," published in Schizophrenia Bulletin, the team details the connections between youth cat ownership and later-in-life schizophrenia-related diagnosis.

The researchers conducted an extensive study search across various databases and gray literature from January 1, 1980, to May 30, 2023, without geographical or language limitations. They included studies reporting original data on cat ownership and schizophrenia-related outcomes. Out of 1,915 identified studies, 17 were used from 11 different countries.

Cat ownership was associated with an increased risk of schizophrenia-related disorders. The unadjusted pooled odds ratio (OR) was 2.35, and the adjusted estimate was 2.24, indicating an over twofold increase in the odds of developing schizophrenia-related disorders among all individuals exposed to cats.

While some studies suggest childhood exposure to cats might be associated with an increased risk of developing schizophrenia-related disorders, the exact age or specific time frame of exposure is not clearly defined across all studies.

One included study from Finland initially reported higher scores on perceptual aberration, schizoid, and social anhedonia scales for those exposed to cats under age seven, though they limited their conclusion to perceptual aberration. Another study from the UK found associations between cat exposure during childhood (at 4 and 10 years) and higher psychotic-like experiences at age 13.

The research suggests that the critical window of exposure needs to be better defined and might be influenced by various factors. More robust investigations are needed to precisely identify the specific period of exposure that might pose the highest risk for schizophrenia-related disorders associated with youth cat exposure.

The overall risk trend focuses on the interaction between the developing brain and feline exposure. But of course, it is not just hanging out with cat personalities that is to blame for the higher risk. There is a causal agent operating unseen in the cat environment that is likely the true culprit—Toxoplasma gondii.

Part1

Comment by Dr. Krishna Kumari Challa on December 18, 2023 at 9:56am

People, not the climate, found to have caused the decline of the giant mammals

For years, scientists have debated whether humans or the climate have caused the population of large mammals to decline dramatically over the past several thousand years. A new study confirms that climate cannot be the explanation.

About 100,000 years ago, the first modern humans migrated out of Africa in large numbers. They were eminent at adapting to new habitats, and they settled in virtually every kind of landscape—from deserts to jungles to the icy taiga in the far north.

Part of the success was human's ability to hunt large animals. With clever hunting techniques and specially built weapons, they perfected the art of killing even the most dangerous mammals.

But unfortunately, the great success of our ancestors came at the expense of the other large mammals.

It is well-known that numerous large species went extinct during the time of worldwide colonization by modern humans. Now, new research reveals that those large mammals that survived also experienced a dramatic decline.

By studying the DNA of 139 living species of large mammals, scientists have been able to show that the abundances of almost all species fell dramatically about 50,000 years ago.

For the past 800,000 years, the globe has fluctuated between ice ages and interglacial periods about every 100,000 years. If the climate was the cause, we should see greater fluctuations when the climate changed prior to 50.000 years ago. But we don't. Humans are, therefore, the most likely explanation.

So far, some of the most important evidence in the debate has been fossils from the past 50,000 years. They show that the strong, selective extinction of large animals in... Therefore, the extinction of animals can hardly be linked to climate.

Juraj Bergman et al, Worldwide Late Pleistocene and Early Holocene population declines in extant megafauna are associated with Homo sapiens expansion rather than climate change, Nature Communications (2023). DOI: 10.1038/s41467-023-43426-5

Comment by Dr. Krishna Kumari Challa on December 18, 2023 at 9:47am

A global biodiversity tipping point as first marine fish extinction declared

A species of ray, so rare it has only ever been recorded once back in the late 1800s, has been declared extinct after an assessment by an international team led by Charles Darwin University (CDU). The loss of the Java Stingaree, a small relative of stingrays, is the first marine fish extinction as a result of human activity.

This news comes as the International Union for Conservation of Nature (IUCN) released its updated Red List of Threatened Species.

The Java Stingaree (Urolophus javanicus) was known only from a single specimen collected in 1862 from a fish market in Jakarta, Indonesia.

The team conducted new modeling encompassing all available information on the species which has revealed the Java Stingaree as extinct.

Intensive and generally unregulated fishing is likely the major threat resulting in the depletion of the Java Stingaree population, with coastal fish catches in the Java Sea already declining by the 1870s.

The northern coast of Java, particularly Jakarta Bay where the species was known to occur, is also heavily industrialized, with extensive, long-term habitat loss and degradation.

These impacts were severe enough to unfortunately cause the extinction of this species.

 www.iucnredlist.org/species/60 … sessment-information

Comment by Dr. Krishna Kumari Challa on December 16, 2023 at 1:33pm

In addition to expanding the possibilities for synthetic biology, the findings also support a hypothesis that dates back to Watson and Crick’s original discovery. This hypothesis, called the tautomer hypothesis, says the standard four nucleotides can form mismatched pairs due to tautomerization, or the tendency of nucleotides to oscillate between several structural variants with the same composition. This phenomenon is thought to be one source of point mutations, or genetic mutations that only impact one base pair in a DNA sequence.

Tautomerization allows nucleotides to come together in pairs when they aren’t usually supposed to. Tautomerization of mispairs has been observed in replication and translation processes, but here we provide the first direct structural evidence that tautomerization also happens during transcription.

Juntaek Oh, Zelin Shan, Shuichi Hoshika, Jun Xu, Jenny Chong, Steven A. Benner, Dmitry Lyumkis, Dong Wang. A unified Watson-Crick geometry drives transcription of six-letter expanded DNA alphabets by E. coli RNA polymerase. Nature Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-43735-9

The researchers are next interested in testing whether the effect they observed here is consistent in other combinations of synthetic base pairs and cellular enzymes.

Part 2

Comment by Dr. Krishna Kumari Challa on December 16, 2023 at 1:32pm

Enzymes can't tell artificial DNA from the real thing

The genetic alphabet contains just four letters, referring to the four nucleotides, the biochemical building blocks that comprise all DNA. Scientists have long wondered whether it’s possible to add more letters to this alphabet by creating brand-new nucleotides in the lab, but the utility of this innovation depends on whether or not cells can actually recognize and use artificial nucleotides to make proteins.

Now, researchers  have come one step closer to unlocking the potential of artificial DNA. They found that RNA polymerase, one of the most important enzymes involved in protein synthesis, was able to recognize and transcribe an artificial base pair in exactly the same manner as it does with natural base pairs.

The findings, published December 12, 2023 in Nature Communications, could help scientists create new medicines by designing custom proteins.
Considering how diverse life on Earth is with just four nucleotides, the possibilities of what could happen if we can add more are enticing. Expanding the genetic code could greatly diversify the range of molecules we can synthesize in the lab and revolutionize how we approach designer proteins as therapeutics.

The four nucleotides that comprise DNA are called adenine (A), thymine (T), guanine (G) and cytosine (C). In a molecule of DNA, nucleotides form base pairs with a unique molecular geometry called Watson and Crick geometry, named for the scientists who discovered the double-helix structure of DNA in 1953. These Watson and Crick pairs always form in the same configurations: A-T and C-G. The double-helix structure of DNA is formed when many Watson and Crick base pairs come together.

This is a remarkably effective system for encoding biological information, which is why serious mistakes in transcription and translation are relatively rare. As scientists have also learned, they may be able to exploit this system by using synthetic base pairs that exhibit the same geometry.

The study uses a new version of the standard genetic alphabet, called the Artificially Expanded Genetic Information System (AEGIS), that incorporates two new base pairs. Originally developed by Benner, AEGIS began as a NASA-supported initiative to try to understand how extraterrestrial life could have developed.

By isolating RNA polymerase enzymes from bacteria and testing their interactions with synthetic base pairs, they found that the synthetic base pairs from AEGIS form a geometric structure that resembles the Watson and Crick geometry of natural base pairs. The result: the enzymes that transcribe DNA can’t tell the difference between these synthetic base pairs and those found in nature.

In biology, structure determines function. By conforming to a similar structure as standard base pairs, our synthetic base pairs can slip in under the radar and be incorporated in the usual transcription process.

Part1

Comment by Dr. Krishna Kumari Challa on December 16, 2023 at 9:20am

Captive Goffin's cockatoos found to dunk hard bread to improve its texture

A pair of veterinary medicine researchers has found that some captive Goffin's cockatoos prefer to dunk their hard bread before eating it, seemingly as a means to improve its texture. In their paper published in the journal Biology Letters, they describe their observations of the birds and their theories on why the birds dunk the bread.

Many animals have been observed dunking food in water before consumption—raccoons are a prime example. Prior research has shown that at least 25 species of birds dunk food in water before consumption, though why they do so has remained unclear. In this new effort, the researchers discovered by happenstance that some of the birds in the lab carried pieces of rusk to a nearby water bowl and dunked it for several seconds before consuming their treat. Rusk is a type of twice-baked, dry and brittle bread that is commonly given to teething babies. In this instance, it is given to captive Goffin's cockatoos as part of their daily rations at the lab.

The researchers report that they happened to note that one of the birds, a male named Pippin, picked up a piece of rusk and headed to a nearby water bowl, normally used for bathing. Once there, he pushed the bread piece underwater and held it there for several seconds. He then pulled the snack from the water and ate it.

Intrigued by their observation, the researchers began to watch more closely as the birds were given their food—the rusk was served along with seeds, bird pellets, dried fruit and cornflakes. As they watched, the researchers noted that several of the birds mimicked the actions of Pippin, though they varied in both dedication and the amount of time they dunked the bread.

After watching the birds eat over a 12-day period, the researchers noted that 7 of the 18 birds in the lab dunked their food—and it was almost always rusk. The birds left the bread in the water for an average of 23 seconds, more than enough time to soften its texture. They also found that some of the birds were willing to go to great lengths to soak their bread before eating it, such as climbing ladders and moving things out of the way.

J. S. Zewald et al, Dunking rusk: innovative food soaking behaviour in Goffin's cockatoos (Cacatua goffiniana), Biology Letters (2023). DOI: 10.1098/rsbl.2023.0411

Comment by Dr. Krishna Kumari Challa on December 16, 2023 at 9:13am

Rubber that doesn't grow cracks when stretched many times

Researchers  have increased the fatigue threshold of particle-reinforced rubber, developing a new, multiscale approach that allows the material to bear high loads and resist crack growth over repeated use. This approach could not only increase the longevity of rubber products such as tires but also reduce the amount of pollution from rubber particles shed during use.

Naturally-occurring rubber latex is soft and stretchy. For a range of applications, including tires, hoses, and dampeners, rubbers are reinforced by rigid particles, such as carbon black and silica. Since their introduction, these particles greatly improve the stiffness of rubbers but not their resistance to crack growth when the material is cyclically stretched, a measurement known as the fatigue threshold.

In fact, the fatigue threshold of particle-reinforced rubbers hasn't improved much since it was first measured in the 1950s. This means that even with the improvements to tires that increase wear resistance and reduce fuel consumption, small cracks can shed large amounts of rubber particles into the environment, which cause air pollution for humans and accumulate into streams and rivers.

Previous research markedly increased the fatigue threshold of rubbers by lengthening polymer chains and densifying entanglements. But how about particle-reinforced rubbers?

The present research team added silica particles to their highly entangled rubber, thinking the particles would increase stiffness but not affect fatigue threshold, as commonly reported in the literature. They were wrong. Adding particles would increase the fatigue threshold and they discovered that it increased by a factor of 10.

This material deconcentrates stress around a crack over two length scales: the scale of polymer chains, and the scale of particles. This combination stops the growth of a crack in the material. The team demonstrated their approach by cutting a crack in a piece of their material and then stretching it tens of thousands of times. In their experiments, the crack never grew.

 Jason Steck et al, Multiscale stress deconcentration amplifies fatigue resistance of rubber, Nature (2023). DOI: 10.1038/s41586-023-06782-2

Comment by Dr. Krishna Kumari Challa on December 15, 2023 at 11:25am

Bilaterally gynandromorphic Green Honeycreeper near Manizales, Colombia, 20 May 2022. Image courtesy: John Murillo.

John Murillo et al, Report of bilateral gynandromorphy in a Green Honeycreeper ( Chlorophanes spiza ) from Colombia, Journal of Field Ornithology (2023). DOI: 10.5751/JFO-00392-940412

Comment by Dr. Krishna Kumari Challa on December 15, 2023 at 11:22am

Extremely rare half female, half male bird captured on film

 A striking and extremely rare half female, half male bird has been spotted by a  zoologist.

Sesquicentennial Distinguished Professor Hamish Spencer was holidaying in Colombia when an amateur ornithologist John Murillo pointed out a wild Green Honeycreeper with distinct half green, or female, and half blue, male, plumage.
Many birdwatchers could go their whole lives and not see a bilateral gynandromorph in any species of bird. The phenomenon is extremely rare in birds.

Photographs of the bird make the discovery even more significant as they are "arguably the best of a wild bilateral gynandromorphic bird of any species ever."

A report on the find, only the second recorded example of gynandromorphism in the species in more than 100 years, has been published in the Journal of Field Ornithology.

Professor Spencer says gynandromorphs—animals with both male and female characteristics in a species that usually have separate sexes—are important for our understanding of sex determination and sexual behavior in birds.

The main groups in which the phenomenon has been recorded include animal species that feature strong sexual dimorphism; most often insects, especially butterflies, crustaceans, spiders, and even lizards and rodents.

"This particular example of bilateral gynandromorphy—male one side and female the other—shows that, as in several other species, either side of the bird can be male or female.

The phenomenon arises from an error during female cell division to produce an egg, followed by double-fertilization by two sperm.

Part 1

Comment by Dr. Krishna Kumari Challa on December 15, 2023 at 8:38am

Nanoparticles amplify potential cancer vaccine power

Researchers have identified minuscule particles that supercharge therapeutic cancer vaccines, which train the immune system to attack tumors. These new lipid nanoparticles—tiny structures made of fat—not only stimulate a two-pronged immune system response that enhances the body's ability to fight cancer but also make vaccines more effective in targeting tumours.

This research marks a pivotal turning point in our understanding of how lipid nanoparticles can be harnessed to optimize anticancer immunity. These findings  unlock new avenues for enhancing the efficacy of RNA-based treatments for cancer and infectious diseases.

Lipid nanoparticles, made famous for their use in delivering messenger RNA in COVID-19 vaccines, have gained attention as carriers in cancer immunotherapy. Previous research focused on optimizing lipid nanoparticles to trigger a strong response by T helper 1 cells, cells that enable the immune system to identify and attack cancerous cells.

Using a new screening method, researchers fine-tuned the composition of lipid nanoparticles to customize and maximize immune-response activation. They identified lipid nanoparticles that generated responses simultaneously using two parallel pathways to present tumor antigens to both Th1 and Th2 cells, another type of helper cell.

The team also combined lipid nanoparticles with "checkpoint inhibitor treatment," a type of cancer immunotherapy drug that helps the immune system recognize and attack cancer cells. These inhibitors block "checkpoints:" molecules on immune cells that either stimulate or inhibit an immune response. Cancer cells sometimes evade these checkpoints and thus go undetected by the immune system. The team's LNPs enhance the therapeutics' ability to reduce tumor size and extend patient survival time.

The researchers say that their study is unique because it demonstrates that lipid nanoparticles can boost both Th1 and Th2 responses, producing coordinated attacks on cancer by multiple immune cell types.

Yining Zhu et al, Screening for lipid nanoparticles that modulate the immune activity of helper T cells towards enhanced antitumour activity, Nature Biomedical Engineering (2023). DOI: 10.1038/s41551-023-01131-0

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