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Category: chemistry

More than 25 years ago, biologists in Arkansas began to report dozens of bald eagles paralyzed, convulsing, or dead. Their brains were pocked with lesions never seen before in eagles. The disease was soon found in other birds across the southeastern United States. Eventually, researchers linked the deaths to a new species of cyanobacteria growing on an invasive aquatic weed that is spreading across the country. The problem persists, with the disease detected regularly in a few birds, yet the culprit’s chemical weapon has remained unknown.

Today in Science, a team identifies a novel neurotoxin produced by the cyanobacteria and shows that it harms not just birds, but fish and invertebrates, too. “This research is a very, very impressive piece of scientific detective work,” says microbiologist Susanna Wood of the Cawthron Institute. An unusual feature of the toxic molecule is the presence of bromine, which is scarce in lakes and rarely found in cyanobacteria. One possible explanation: the cyanobacteria produce the toxin from a bromide-containing herbicide that lake managers use to control the weed.

The discovery highlights the threat of toxic cyanobacteria that grow in sediment and on plants, Wood says, where routine water quality monitoring might miss them. The finding also equips researchers to survey lakes, wildlife, and other cyanobacteria for the new toxin. “It will be very useful,” says Judy Westrick, a chemist who studies cyanobacterial toxins at Wayne State University and was not involved in the new research. “I started jumping because I got so excited.”

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Stanford University neurobiologist Sergiu Pașca has been making brain organoids for about 10 years, and his team has learned that some of these tissue blobs can thrive in a dish for years. In the new study, they teamed up with neurogeneticist Daniel Geschwind and colleagues at the University of California, Los Angeles (UCLA), to analyze how the blobs changed over their life spans…

…They noticed that when an organoid reached 250 to 300 days old—roughly 9 months—its gene expression shifted to more closely resemble that of cells from human brains soon after birth. The cells’ patterns of methylation—chemical tags that can affix to DNA and influence gene activity—also corresponded to increasingly mature human brain cells as the organoids aged, the team reports today in Nature Neuroscience.

Organoids develop genetic signatures of postnatal brains, possibly broadening their use as disease models.

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Doctors take a microscopic craft loaded with cancer-killing chemicals, inject it into the human body, and drive it to a malignant tumor to deliver its payload before making a quick exit. The plan is to move to clinical trials by 2023.

Chemotherapy and radiation can cause too much collateral damage to treat some brain tumors. Crumb-sized robots could be the solution.

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Bacteria have been found exploiting quantum physics to survive.

Oxygen is life to animals like us. But for many species of microbe, the smallest whiff of the highly reactive element puts their delicate chemical machinery at risk of rusting up.

The photosynthesizing bacterium Chlorobium tepidum has evolved a clever way to shield its light-harvesting processes from oxygen’s poisonous effects, using a quantum effect to shift its energy production line into low gear.

A study conducted by scientists from the University of Chicago and Washington University in St. Louis has shown how the bacterium throws a spanner into its quantum resonance to ‘tune’ its system so that it loses energy in the presence of oxygen, preventing it from wrecking its photosynthetic apparatus.

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Using an improved version of the gene editing tool CRISPR/Cas9, researchers knocked out up to twelve genes in plants in a single blow. Until now, this had only been possible for single or small groups of genes. The approach was developed by researchers at Martin Luther University Halle-Wittenberg (MLU) and the Leibniz Institute of Plant Biochemistry (IPB). The method makes it easier to investigate the interaction of various genes. The study appeared in The Plant Journal.

The inheritance of traits in is rarely as simple and straightforward as Gregor Mendel described. The monk, whose experiments in the 19th century on trait inheritance in peas laid the foundation of genetics, in fact got lucky. “In the traits that Mendel studied, the rule that only one gene determines a specific trait, for example the color of the peas, happened to apply,” says plant geneticist Dr. Johannes Stuttmann from the Institute of Biology at MLU. According to the researcher, things are often much more complicated. Frequently there are different that, through their interaction with one another, result in certain traits or they are partly redundant, in other words they result in the same trait. In this case, when only one of these genes is switched off, the effects are not visible in the plants.

The scientists at MLU and IPB have now developed a way to study this complex phenomenon in a more targeted way by improving CRISPR/Cas9. These gene editing tools can be used to cut the DNA of organisms at specific sites. The team built on the work of biologist Dr. Sylvestre Marillonnet who developed an optimized building block for the CRISPR/Cas9 system at the IPB. “This building block helps to produce significantly more Cas9 enzyme in the plants, which acts as a scissor for the genetic material,” explains Stuttmann. The researchers added up to 24 different guide RNAs which guide the scissor enzyme to the desired locations in the genetic material. Experiments on thale cress (Arabidopsis thaliana) and the wild tobacco plant Nicotiana benthamiana proved that the approach works. Up to eight genes could be switched off simultaneously in the tobacco plants while, in the thale cress, up to twelve genes could be switched off in some cases.

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The FDA does not use modern updated science to retest chemicals in food. This study showed that a common food preservative can increase food allergies and damage the immune system.

New science suggests the FDA should test all food chemicals for safety.

A food preservative used to prolong the shelf life of Pop-Tarts, Rice Krispies Treats, Cheez-Its and almost 1250 other popular processed foods may harm the immune system, according to a new peer-reviewed study by Environmental Working Group.

For the study, published this week in the International Journal of Environmental Research and Public Health, EWG researchers used data from the Environmental Protection Agency’s Toxicity Forecaster, or ToxCast, to assess the health hazards of the most common chemicals added to food, as well as the “forever chemicals” known as PFAS, which can migrate to food from packaging.

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AuthorResearch paper: https://pubs.acs.org/doi/10.1021/acs.est.0c05984

Scientists Detect 55 Chemicals Never Before Reported in People – 42 “Mystery Chemicals” Whose Sources Are Unknown

https://particleandfibretoxicology.biomedcentral.com/articles/10.1186/s12989-020-00385-9

Hashem Al-Ghaili.

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Furthermore, it implies that defects in the repair process, not the DNA damage itself, can potentially lead to developmental or neurodegenerative diseases.

Researchers at the National Institutes of Health (NIH) have discovered specific regions within the DNA of neurons that accumulate a certain type of damage (called single-strand breaks or SSBs). This accumulation of SSBs appears to be unique to neurons, and it challenges what is generally understood about the cause of DNA damage and its potential implications in neurodegenerative diseases.

Because neurons require considerable amounts of oxygen to function properly, they are exposed to high levels of free radicals—toxic compounds that can damage DNA within cells. Normally, this damage occurs randomly. However, in this study, damage within neurons was often found within specific regions of DNA called “enhancers” that control the activity of nearby genes.

Fully mature cells like neurons do not need all of their genes to be active at any one time. One way that cells can control gene activity involves the presence or absence of a chemical tag called a methyl group on a specific building block of DNA. Closer inspection of the neurons revealed that a significant number of SSBs occurred when methyl groups were removed, which typically makes that gene available to be activated.

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“The results were surprising, but convincing, says Yannick Pauchet, a molecular entomologist also at the Max Planck Institute for Chemical Ecology. ” According to the data they provide, horizontal gene transfer is the most parsimonious explanation,” he says.

But how the whitefly managed to swipe a plant gene is unclear. One possibility, says Turlings, is that a virus served as an intermediate, shuttling genetic material from a plant into the whitefly genome.

As researchers s… See More.

Discovery that a whitefly uses a stolen plant gene to elude its host’s defences may offer a route to new pest-control strategies.

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Plastics are one of the world’s largest polluters, taking hundreds of years to degrade in nature. A research team, led by YSE professor Yuan Yao and Liangbing Hu from the University of Maryland, has created a high-quality bioplastic from wood byproducts that they hope can solve one of the world’s most pressing environmental issues.

Efforts to shift from petrochemical plastics to renewable and biodegradable plastics have proven tricky — the production process can require toxic chemicals and is expensive, and the mechanical strength and water stability is often insufficient. But researchers have made a breakthrough, using wood byproducts, that shows promise for producing more durable and sustainable bioplastics.

A study published in Nature Sustainability, co-authored by Yuan Yao, assistant professor of industrial ecology and sustainable systems at Yale School of the Environment (YSE), outlines the process of deconstructing the porous matrix of natural wood into a slurry. The researchers say the resulting material shows a high mechanical strength, stability when holding liquids, and UV-light resistance. It can also be recycled or safely biodegraded in the natural environment, and has a lower life-cycle environmental impact when compared with petroleum-based plastics and other biodegradable plastics.

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