Comment

Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 11:15am

Plastic in foraminifera and possible consequences for the environment

Single-celled organisms with calcareous shells, called foraminifera, contribute significantly to the formation of sand deposited on beaches, islands and coastal areas. Researchers  have now found for the first time that foraminifera can take up tiny plastic particles and incorporate them into their calcareous shells. The results were published in Scientific Reports and Limnology and Oceanography Letters.

Gleaming white tropical beaches are coveted destinations for many recreation-seekers. But how do we perceive such beaches if we have to fear that they consist to a not inconsiderable extent of micro- and nanoplastics—invisible to our eyes?

Tropical beaches are mainly formed by calcifying marine animals such as corals, mussels and snails. The fact that corals incorporate microplastics into their calcareous skeleton has already been proven in studies. In some regions of the world, however, such as Indonesia, the Philippines and Australia, many beaches consist largely of the calcareous shells of foraminifera. These are single-celled organisms, a few millimeters in size and with a protective calcareous shell, that can be found in warm, shallow coastal areas worldwide.

Foraminifera feed on, among other things, microalgae or organic material particles they find on the seafloor. Micro- and nanoplastic particles have similar sizes and could easily be mistaken for potential food.

In a series of experiments, the team exposed several hundred foraminifera to seawater tanks for several weeks. They fed them partly with tiny micro- or nanoplastic particles, partly with natural food particles or a mixture of both. They observed that while the foraminifera preferred the natural food, when both were available at the same time, they frequently ate plastic pieces.

Using a fluorescence microscope, the researchers were able to observe a large number of yellow glowing nanoplastic particles in the foraminifera. Although some of the unicellular organisms rejected the plastic after the feeding experiments, about half of the foraminifera retained the plastic load inside the cell.

After eight weeks, a scanning electron microscope with 80,000x magnification revealed that many of the single-celled organisms had already encrusted the plastic particles with a layer of calcium carbonate and were apparently in the process of incorporating them into their shell.

So if the plastic particles are small enough, the foraminifera will take them in as food. For the environment, this could have advantages and disadvantages. For example, the trillions of foraminifera on the seafloor could be a sink for nanoplastics, a system that removes plastic from the ocean.

One problem the researcher sees, however, is potential impacts on the health of the foraminifera. On beaches and in shallow marine areas, the shells of foraminifera are often deposited at high densities of more than 1 kg per m2. However, if the protozoa interchange plastic particles with their natural food and incorporate them into their calcareous shells, their fitness, shell formation and stability could be disrupted—with consequences for their population as a whole.
Part 1

Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 10:33am

This is why the cell will identify ERV sequences and recruit dedicated repressive machinery to their sites and keep them silent. Additionally, the chromosome is getting compacted at these sites.

But what happens if you turn off these protective mechanisms? Chaos!

Vahid Asimi et al, Hijacking of transcriptional condensates by endogenous retroviruses, Nature Genetics (2022). DOI: 10.1038/s41588-022-01132-w

Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 10:32am

Zombie viruses on a hijacking trip: Retroviral gene fragments affect embryonic cells

Ancient, dormant sequences in the genome impact embryonic development in unexpected ways. The mammalian genome contains retroviral sequences that are in an undead but mostly "harmless" state. An international research team recently discovered how some of these retroviral gene fragments affect embryonic cells if they are unleashed. Unexpectedly, not the viral proteins, but rather copies of the genetic material itself generate an imbalance in the cell.

Over thousands of years of evolution, countless viruses have embedded themselves in our genome. A staggering ten percent of mammalian genomes consist of ancient retroviral sequences. These no longer seem to pose any danger, because most of them have mutated beyond recognition. Additionally, these genes have been epigenetically silenced by the cell. But as the silencing of the viral remains fails, they will rise from their graves, causing chaos in the cell.

Researchers found that the messenger copies of some of the viral genes, the RNA, have an important impact on embryonic cells. The viral sequences seem to remember their original mission of hijacking the molecular machinery that ensures the flow of information from DNA to RNA to protein. Interestingly, the messenger RNA itself seems to be responsible.

Scientists  described that the RNA of the resurrected viruses exerts attractive forces on the enzymes that read the information from the DNA. The tasks of the embryonic cell—such as reading important embryonic genes—are neglected and a fatal imbalance develops. This unleashed state occurs, for example, in some types of cancer and neurological diseases.

Viruses are cleverly constructed snippets of genetic information. Some of them incorporate themselves into the genome of their hosts and persist there. Thousands of copies of Endogenous Retroviruses (ERVs) have spread throughout mammalian genomes, often in droves of hundreds of repetitive copies.

As retroviruses jump from one section of DNA to the next during their life cycle, they can alter genes and even recombine them. This makes them an important tool for evolution to create new genes. For an individual organism however, uncontrolled gene modification does not bode well, especially during embryonic development. 

Part 1

Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 9:43am

Of these two species, the first is avoided by cattle and is used in traditional medicine as a pain reliever, sedative, and immune booster. The second is toxic for humans and cattle if eaten in great quantities. They also have nutritional value: fatty acids abound in corn poppy seeds, while the seeds of purple viper's bugloss are rich in edible oils.

The authors isolated water- and fat-soluble compounds from both species and determined their chemical identity with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (HPLC-MS). They focused on lipids, volatile essential oils, and alkaloids, produced by many plants as defense against herbivores. For example, they found that corn poppies are rich in bioactive alkaloids like rhoeadine, rhoeagenine, epiberberine, and canadine.

The authors then tested the activity of the isolated molecular fractions against three common parasites of birds: the protozoon Trichomonas gallinae, the nematode (parasitic worm) Meloidogyne javanica, and the fungus Aspergillus niger.

The results show that extracts from both plants are highly effective at inhibiting or killing protozoa and nematodes in vitro, while purple viper's bugloss is also moderately active against fungi.

The authors conclude that great bustards are prime candidates for birds that seek out specific plants to self-medicate. But more research is needed, they caution.The ultimate proof of self-medication requires experimental protocols developed in the biomedical, veterinary, and pharmacological sciences.

Luis M. Bautista-Sopelana et al, Bioactivity of plants eaten by wild birds against laboratory models of parasites and pathogens, Frontiers in Ecology and Evolution (2022). DOI: 10.3389/fevo.2022.1027201

Part 2

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Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 9:42am

World's heaviest flying bird may be self-medicating on plants used in traditional medicine

Do you think only humans can use plant based medicines based on experience? Then think again. Even animals can do this. Humans aren't the only species that self-medicates.

If you see a great bustard (Otis tarda) in the wild, you're unlikely to forget it. Massive, colorful, and impossible to mistake, they are the heaviest birds living today capable of flight, with the greatest size difference between the sexes. They are also "lek breeders," where males gather at chosen sites to put on an audiovisual show for the visiting females, who choose a mate based on his appearance and the quality of his showbirdship.

But now, a study in Frontiers in Ecology and Evolution suggests that great bustards have another claim to our interest: they actively seek out two plants with compounds that can kill pathogens. They may thus be a rare example of a bird that uses plants against disease—that is, self-medication.

Self-medication in animals is suspected to occur, with a lesser or greater degree of confidence, in animals as diverse as primates, bears, deer, elk, macaws, honeybees, and fruit flies. But it's tricky to prove beyond doubt in wild animals.

We can't compare between control and experimental treatments. And double-blind trials or dose-effect studies, obligatory steps in human or veterinary medicine, are obviously impossible in wild animals.

Great bustards breed on grasslands from western Europe and northwest Africa to central and eastern Asia. Approximately 70% of the world's population live in the Iberian peninsula. Females typically remain faithful to the home range where they hatched for life—10 to 15 years—while after dispersal, males revisit the same lake site year after year. By staying (and importantly, pooping) in the same area for prolonged periods, they risk re-infecting themselves. And males need exceptional stamina during the mating season, which is expected to cause their immune defenses to nose-dive.

In theory, both sexes of great bustards might benefit from seeking out medicinal plants in the mating season when sexually transmitted diseases are common—while males that use plants with compounds active against diseases might appear more healthy, vigorous, and attractive to females.

The  research team have studied great bustards since since the early 1980s, mainly in the regions of Madrid and Castille-Leon, Spain. They collected a total of 623 droppings from female and male great bustards, including 178 during the mating season in April. Under a microscope, they counted the abundance of recognizable remains (tissue from stems, leaves, and flowers) of 90 plant species that grow locally and are known to on the bustards' menu.

The results showed that two species are eaten by great bustards more often than expected from their abundance: corn poppies, Papaver rhoeas and purple viper's bugloss, Echium plantagineum.

"Great bustards select corn poppies and purple viper's bugloss mainly in the mating season , in April, when their energy expenditure is greatest. And males, who during these months spend much of their time and energy budgets on sexual display, prefer them more than females.

Part 1

Comment by Dr. Krishna Kumari Challa on November 24, 2022 at 7:36am

Major discovery about mammalian brains

In a new breakthrough to understand more about the mammalian brain, University of Copenhagen researchers have made an incredible discovery. Namely, a vital enzyme that enables brain signals is switching on and off at random, even taking hours-long "breaks from work". These findings may have a major impact on our understanding of the brain and the development of pharmaceuticals.

Millions of neurons are constantly messaging each other to shape thoughts and memories and let us move our bodies at will. When two neurons meet to exchange a message, neurotransmitters are transported from one neuron to another with the aid of a unique enzyme.

This process is crucial for neuronal communication and the survival of all complex organisms. Until now, researchers worldwide thought that these enzymes were active at all times to convey essential signals continuously. But this is far from the case.

Using an innovative method, researchers  have closely studied the enzyme and discovered that its activity is switching on and off at random intervals, which contradicts our previous understanding.

This is the first time anyone has studied these mammalian brain enzymes one molecule at a time, and we are awed by the result. Contrary to popular belief, and unlike many other proteins, these enzymes could stop working for minutes to hours. Still, the brains of humans and other mammals are miraculously able to function.

Dimitrios Stamou, Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching, Nature (2022). DOI: 10.1038/s41586-022-05472-9

Comment by Dr. Krishna Kumari Challa on November 23, 2022 at 9:39am

The interplay between epidemics, prevention information, and mass media

When an epidemic strikes, more than just infections spread. As cases mount, information about the disease, how to spot it, and how to prevent it propagates rapidly among people in affected areas as well. Relatively little is known, however, about the interplay between the course of epidemics and this diffusion of information to the public.

A pair of researchers developed a model that examines epidemics through two lenses—the spread of disease and the spread of information—to understand how reliable information can be better disseminated during these events. 

They report their two-layered model can predict the effects of mass media and infection prevention information on the epidemic threshold.

To tackle their question, the researchers' model compares the interactions between two layers of information. The first is the transmission of the disease itself, propagated through physical contact between people. The second occupies the information space of social networks, where different voices are sharing the do's and don'ts of infection prevention, called positive and negative information respectively. The model provides a set of equations that can be used to calculate the epidemic threshold using a technique called microscopic Markov chains. Central to this calculation is the time delay between becoming infected and recovering. The longer it takes for patients to recover from an infection, they found, the less likely a patient is cured, leading to a lower recovery rate and making it easier for a disease to break out. Disseminating effective prevention practices and using mass media, however, can increase the epidemic threshold, making it more difficult for the infection to spread. They simulate this by reducing the time delays related to recovery, which boosts recovery rates.

 The impact of positive and negative information on SIR-like epidemics in delayed multiplex networks, Chaos An Interdisciplinary Journal of Nonlinear Science (2022). DOI: 10.1063/5.0126799

Comment by Dr. Krishna Kumari Challa on November 23, 2022 at 9:34am

Scientists unlock nature's secret to super-selective binding

 Researchers have discovered that it is not just molecular density, but also pattern and structural rigidity, that control super-selective binding interactions between nanomaterials and protein surfaces. The breakthrough could help optimize existing approaches to virus prevention and cancer detection.

So much of biology comes down to the biophysical process of binding: making a strong connection between one or more groups of atoms—known as ligands—to their corresponding receptor molecule on a surface. A binding event is the first fundamental process that allows a virus to infect a host, or chemotherapy to fight cancer. But binding interactions—at least, our understanding of them—have a "Goldilocks problem": too few ligands on one molecule makes it impossible for it to stably bind with the correct target, while too many can result in undesirable side-effects.

When binding is triggered by a threshold density of target receptors, scientists call this 'super-selective' binding, which is key to preventing random interactions that could dysregulate biological function. 

Since nature typically doesn't overcomplicate things, researchers wanted to know the minimum number of binding interactions that would still allow for super-selective binding to occur. They were also interested to know whether the pattern the ligand molecules are arranged in makes a difference in selectivity. As it turns out, it does.

They have recently published a study in the Journal of the American Chemical Society that identifies the optimal ligand number for super-selective binding: six. But they also found, to their excitement, that the arrangement of these ligands—in a line, circle, or triangle, for example—also significantly impacted binding efficacy. They have dubbed the phenomenon "multivalent pattern recognition" or MPR.

After engineering a series of ligand-receptor architectures to explore how density, geometry, and nano-spacing influenced binding super-selectivity, the team realized that rigidity was a key factor. The more flexible, the less precise.

Diagnostics and therapeutics such as chemotherapy could also benefit from super-selectivity, which could allow for more reliable binding with cancer cells, for which certain receptor molecules are known to have a higher density. In this case, healthy cells would remain undetected, drastically reducing side effects.

Finally, such selectivity engineering could offer key insights into complex interactions within the immune system.

Hale Bila et al, Multivalent Pattern Recognition through Control of Nano-Spacing in Low-Valency Super-Selective Materials, Journal of the American Chemical Society (2022). DOI: 10.1021/jacs.2c08529

Comment by Dr. Krishna Kumari Challa on November 23, 2022 at 8:41am

Things that make  people feel more awake and alert during mornings and afternoons

A team of researchers affiliated with multiple institutions has isolated factors that they think have an impact on how awake and/or alert people feel during the day.

Prior research has shown that more people than ever are complaining of feeling tired, sleepy and unalert during the daytime. Such complaints have been connected to increases in motor vehicle and work accidents and also sloppy job performance. In this new effort, the researchers noted that little research has been conducted looking into the factors that contribute to daytime alertness. To rectify that problem, they conducted a study of their own.

The researchers recruited 833 volunteers (many of whom were either identical or fraternal twins) to undergo testing for two weeks. Each adhered to a prescribed diet and wore a watch that recorded their sleep and physical activity and also their glucose levels. They also recorded the food they ate using a custom phone app, which they also used to record their level of alertness. After the two-week period, the researchers found some patterns. For example, those people who slept longer reported feeling more alert the next day—no surprise there.

But they also found that it was not duration that led to an increase in alertness, but the time that they woke up—waking up later than normal, they found, made the volunteers feel more alert, at least during the morning, even if they did not go to bed late. They also found that the volunteers were more alert on days when they were physically active the day before. And they found that eating a high-carb breakfast, such as muffins, resulted in higher morning alertness.

Drinking pure glucose had them feeling even more alert. A high-protein breakfast, on the other hand, had the volunteers dragging in the morning. The researchers also found four factors that most contributed to daily variances for the volunteers: age, sleep, mood and frequency of eating—eating less often seemed to reduce next-day fatigue.

Raphael Vallat et al, How people wake up is associated with previous night's sleep together with physical activity and food intake, Nature Communications (2022). DOI: 10.1038/s41467-022-34503-2

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Comment by Dr. Krishna Kumari Challa on November 22, 2022 at 11:10am

A combination of ultrasound and nanobubbles allows cancerous tumors...

A new technology developed at Tel Aviv University makes it possible to destroy cancerous tumors in a targeted manner, via a combination of ultrasound and the injection of nanobubbles into the bloodstream. According to the research team, unlike invasive treatment methods or the injection of microbubbles into the tumor itself, this latest technology enables the destruction of the tumor in a non-invasive manner.

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Researchers develop a new type of light-sensitive nanoparticle to h...

Oregon State University scientists have produced a proof of concept for a new and better way of caring for women facing the life-threatening situation of ectopic pregnancy, which occurs when a fertilized egg implants somewhere other than the lining of the uterus.

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