Comment

Comment by Dr. Krishna Kumari Challa on December 19, 2023 at 1:17pm

When exposed to PFOS and PFOA, the cells showed increased movement and a higher tendency of spreading. In a different test with CRC cells grown in a flat layer, a line was scratched down the middle to split them. When the chemicals were introduced, the cells grew and moved toward each other again.

To dig deeper, the researchers examined the chemicals' effects on the cell's metabolism. PFAS exposure altered various metabolites crucial for cell function, like amino acids and fatty acids, as well as signaling proteins associated with metastasis.

Substances that are usually anti-inflammatory and protective against cancer were reduced in the CRC cells after exposure, too. Some differences were more noticeable in the mutated cells, which could mean that cancers with this mutation may be more likely to spread with exposure to PFAS.

These results in the lab indicate that exposure to high levels of PFOS and PFOA could potentially increase the risk of CRC spreading in real-life conditions. This is crucial information for those in jobs with potential high exposure, the team says, and monitoring these chemicals is key to safeguarding their health, as are future clinical studies.

"Many in vitro studies can't be translated into humans but  understanding first the mechanisms of how they can actually affect cancer cell growth is important."

https://pubs.acs.org/doi/10.1021/acs.est.3c04844

**

Part 2

Comment by Dr. Krishna Kumari Challa on December 19, 2023 at 1:16pm

Common Forever Chemicals May Trigger Cancer Cells to Spread

When colorectal cancer cells are exposed to two different types of 'forever chemicals' in the lab, the chemicals can potentially accelerate cancer progression, new research suggests.

A new study conducted an analysis of exposure levels comparable to those found in firefighters and other people who come into regular contact with per- and poly-fluoroalkyl substances (PFAS). Firefighters' blood levels of PFAS tend to be higher than the general population's because of their frequent exposure to firefighting foam, which contains PFAS chemicals for its flame retardant properties. Firefighters are more likely than the general population to develop and die from a variety of cancers that include colorectal cancer. Environmental factors are believed to be related to about 80 percent of CRC cases. In the new research, PFAS exposure in the lab induced CRC cells to migrate to new positions, implying a potential role in cancer spreading (metastasis) in living organisms. It doesn't prove it's metastasis, but they have increased motility, which is a feature of metastasis, according to researchers.

PFAS are human-made chemicals based on carbon-fluorine bonds, and as the nickname 'forever chemicals' suggests, these bonds are very strong and resistant to degradation, which makes PFAS popular for use in many kinds of products. Unfortunately, it also allows them to survive in the environment for years in ever-increasing concentrations.

They have been frequently detected in the environment, such as in drinking water, indoor dust, cleaning products, and coatings.

Many of these 'forever chemicals' are still present in everyday items, though the hazards of PFAS are largely unclear – partially because of the many different compounds involved. Research has shown that these long-lasting chemicals spread throughout the environment, and exposure to high levels has been linked to harmful health effects in people and animals. Perfluorooctanoic acid (PFOA), a widely used PFAS, was classified as carcinogenic to humans by the International Agency for Research on Cancer in November 2023, and perfluorooctanesulfonic acid (PFOS), another common PFAS, was classified as possibly carcinogenic to humans.

Part 1

Comment by Dr. Krishna Kumari Challa on December 19, 2023 at 9:57am

A framework to train multi-skilled robots for domestic use

Roboticists have been trying to develop robots that can tackle various everyday house chores, such as washing dishes or tidying up, for several years. However, so far none of the robots created has been commercialized adopted on a large scale.

Researchers  recently introduced Dobb-E, a new framework specifically designed to effectively train mobile robots on domestic tasks, ultimately contributing to their future widespread use. This framework, outlined in a paper pre-published on the server arXiv, could be applied to various robots designed to assist humans in their homes.

We already have specialist 'robots' in our homes, such as a dishwasher or a laundry machines, but a generalist robot that can learn how to complete each home-work and how it can help best in that situation has been a distant goal for all too long now.

So researchers developed an ergonomic demonstration collection tool, enabling us to gather task-specific demonstrations in unfamiliar homes without direct robot operation.

The Dobb-E framework has four key components, namely a data collection tool, a pre-trained model, a diverse data set and a deployment scheme. 

Remarkably, the robot was taught to complete 109 different household tasks. For each of these tasks, the researchers fine-tuned their model with five minutes of new video data on average.

The most exciting result of this paper is the confirmation that with our current level of technology we can build learned robotic agents that can address a wide range of tasks in a similarly large range of homes.

Now I want to buy one!

Nur Muhammad Mahi Shafiullah et al, On Bringing Robots Home, arXiv (2023). DOI: 10.48550/arxiv.2311.16098

Comment by Dr. Krishna Kumari Challa on December 18, 2023 at 11:17am

The connection to cats has to do with T. gondii's affinity for reproducing only in domestic cats. This affinity may be related to the lack of a single enzyme in feline guts, delta-6-desaturase.

While any mammal can become infected by the parasite, the digestive enzyme delta-6-desaturase prevents the parasite from getting high enough levels of linoleic acid the parasite requires to fuel reproduction.

Unlike all other mammals, cats are full of linoleic acid due to not producing the data-6-desaturase enzyme that would convert linoleic acid to oleic acid. So, the parasite only reproduces in cat intestines.

Cats then shed oocytes (protozoan parasite eggs) by the millions when they defecate, trapping them on fur and paw used to dutifully cover up their deposit, tracking them wherever a cat's paw may wander.

With the parasite completing its lifecycle, it may not affect the rest of cat biology. In humans and other animals, the failure to turn into the larger reproductive form allows the tiny parasite to migrate past the blood-brain barrier, where the disruption occurs.

The missing enzyme and the independent social lives of outdoor cats, mingling in shared sandboxes and loose garden soils around the world, make cat contact the primary vector for the infection. The secondary vector would be anything that has been in contact with a cat, such as a kitchen counter or any surface a cat has walked on or rubbed against.

While social media has clearly made the case that society would crumble without cats, it is important for all cat owners never to allow their cats outdoors to prevent the continued spread of the T. gondii parasite.

It is even more important that parents, with or without cats, understand the danger cat-borne parasites can pose to the long-term mental health of their children.

More information: John J McGrath et al, Cat Ownership and Schizophrenia-Related Disorders and Psychotic-Like Experiences: A Systematic Review and Meta-Analysis, Schizophrenia Bulletin (2023). DOI: 10.1093/schbul/sbad168

E. F. Torrey et al, Toxoplasma gondii and Other Risk Factors for Schizophrenia: An Update, Schizophrenia Bulletin (2012). DOI: 10.1093/schbul/sbs043

Part 3

**

Comment by Dr. Krishna Kumari Challa on December 18, 2023 at 11:16am

Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that causes toxoplasmosis, an infection that around 25% of the world population has gotten at some point.

It is the reason kitty litter bags have a warning label for pregnant women to avoid contact with cat feces, as toxoplasmosis infection is the leading cause of newborn blindness globally, as well as later vision loss, mental disability, and seizures.

Toxoplasmosis can be a significant cause of death among people with severely weakened immune systems. A daily drug is taken by patients with AIDS, undergoing organ transplant, or with intense chemotherapy treatments just to counter the effects of this one parasite.

T. gondii has previously been linked with all sorts of neurological impairments and behavioural changes, from guilt issues to novelty seeking and increased car accidents. Some presentations of schizophrenia can be reversed by antiprotozoal drugs, suggesting that a T. gondii infection may have been the root cause of those case symptoms.

A 2012 meta-analysis of 38 studies, "Toxoplasma gondii and Other Risk Factors for Schizophrenia," also published in Schizophrenia Bulletin, found that patients with schizophrenia were nearly three times more likely to have toxoplasma antibodies in their blood, suggesting past infections were far more prevalent with the pathology.

A striking find in that study, while comparing risk factors for schizophrenia, was the discrepancy between the risk associated with having a first-degree relative with schizophrenia (RR 6.99–9.31) and the risk associated with specific genetic polymorphisms (OR 1.09–1.24). While a family disease pattern can suggest the involvement of shared genes, it can also point to nongenetic factors like environmental exposure to an infectious agent, like a chemical superfund site, or cats.

Toxoplasmosis has also been linked to various wildlife illnesses, as behavioral changes in wild animals often result in poor survival strategies. Rats, for example, become unafraid of cats while infected. It is a common comorbidity for most California sea lions found distressed or dead to have a toxoplasma infection. If anyone is wondering how a sea lion has contact with a cat, try to see a sandy beach from a cat's perspective. That and the human habit of flushing cat litter have created a massive problem for marine mammals.

Part 2

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

• ‹ Previous
• 1
• …
• 303
• 304
• 305
• 306
• 307
• …
• 1085
• Next ›
• Page