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Comment by Dr. Krishna Kumari Challa on November 26, 2022 at 11:04am

Wolves infected with a common parasite may be much more likely to become pack leaders

A team of researchers with the Yellowstone Wolf Project at the Yellowstone Center for Resources, in Yellowstone National Park, in Wyoming, has found that wolves in the park who become infected with Toxoplasma gondii, a common parasite, are much more likely to become leaders of their pack. In their study, reported in the journal Communications Biology, the group analyzed data from studies of the wolves in the park over a 26-year period.

T. gondii is an obligate parasite that infects the protozoa in cells of infected animals. Such infections are known as toxoplasmosis, and they occur in almost all warm-blooded animals, including humans. Prior research has shown that in most cases, symptoms are few, through there is some evidence that suggests that they can lead to an increase in erratic or aggressive behaviour.

In this new effort, the researchers wondered what sort of impact of T. gondii infections might have on wild wolves. To find out, they conducted an extensive study of wolves living in Yellowstone National Park.

The work involved studying data from blood samples taken from over 200 wolves living in the park over the years 1995–2020, while looking for evidence of infection. The researchers also looked at the notes made by research observers to learn more about any behavior changes that might have been evident in the wolves.

The researchers found that young, infected wolves tended to leave their packs earlier than those uninfected. Infected males were 50% more likely to leave their pack as early as six months after birth. Males normally stay for up to 21 months. And infected females were 25% more likely to leave their pack at 30 months, rather than the normal 48.

The researchers also found that infected males were more than 46 times more likely to become pack leaders than uninfected males. The researchers also found that infection rates were higher in wolves that mingled with cougars. The researchers suggest the differences in behavior were likely due to the impact of the parasite on the brains of wolves, making them bolder and less likely to back down when challenged by others.

Connor J. Meyer et al, Parasitic infection increases risk-taking in a social, intermediate host carnivore, Communications Biology (2022). DOI: 10.1038/s42003-022-04122-0

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 11:32am

Honeypot ants

Bees aren’t the only insects to make honey, some ants can make the sweet treat too.

The honeypot ant, Camponotus inflatus, lives in the deserts of Australia where worker bees harvest nectar from the flowers of the mulga tree. The bees carry it underground and feed it to specialised workers known as ‘rotunds’ whose job it is to dangle upside down and eat.

Indeed, the tubby little insects are fed so much nectar that their abdomens swell up to the size of a small grape, and the abdomen wall is stretched so thin that the honey can be seen inside.

The rotunds form roughly 50 per cent of the colony, and live in cool, underground galleries. They are highly prized by Indigenous Australians who have been excavating and eating them for thousands of years. In the 1990 documentary, Trials Of Life, David Attenborough was filmed quaffing one.

The honey is said to be runnier and less sweet than the better-known bee alternative, but remains rich in antioxidants.

These literal honeypots are an insurance policy against hard times. When the regular workers run out of food, they stroke the rotunds’ antennae, causing the ants to regurgitate the stored honey. They also groom and clean the honeypots to keep the living larders in good condition.

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 10:55am

To stop new viruses jumping across to humans, we must protect and restore bat habitat

Bats have lived with coronaviruses for millennia. Details are still hazy about how one of these viruses evolved into SARS-CoV-2, which causes COVID in humans. Did it go directly from bats to humans or via another animal species? When? And why? If we can't answer these questions for this now-infamous virus, we have little hope of preventing the next pandemic.

Some bat species are hosts for other viruses lethal to humans, from rabies to Nipah to Hendra. But their supercharged immune systems allow them to co-exist with these viruses without appearing sick.

So what can we do to prevent these viruses emerging in the first place? Researchers found one surprisingly simple answer in their new research on flying foxes in Australia: protect and restore native bat habitat to boost natural protection.

When we destroy native forests, we force nectar-eating flying foxes into survival mode. They shift from primarily nomadic animals following eucalypt flowering and forming large roosts to less mobile animals living in a large number of small roosts near agricultural land where they may come in contact with horses.

Hendra virus is carried by bats and can spill over to horses. It doesn't often spread from horses to humans, but when it does, it's extremely dangerous.

Now we know how habitat destruction and spillover are linked, we can act. Protecting the eucalyptus species flying foxes rely on will reduce the risk of the virus spreading to horses and then humans. The data scientists gathered also makes it possible to predict times of heightened Hendra virus risk—up to two years in advance.

By restoring and protecting the natural barriers which for so long kept us safe from bat-borne viruses. It is far better to prevent viruses from spilling over in the first place than to scramble to stop a possible pandemic once it's begun.

Planting trees can help stop dangerous new viruses reaching us. It really is as simple as that.

 Peggy Eby et al, Pathogen spillover driven by rapid changes in bat ecology, Nature (2022). DOI: 10.1038/s41586-022-05506-2

https://phys.org/news/2022-11-viruses-humans-habitat.html?utm_sourc...

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 10:51am

To stop new viruses jumping across to humans, we must protect and r...

Bats have lived with coronaviruses for millennia. Details are still hazy about how one of these viruses evolved into SARS-CoV-2, which causes COVID in humans. Did it go directly from bats to humans or via another animal species? When? And why? If we can't answer these questions for this now-infamous virus, we have little hope of preventing the next pandemic.

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Researchers explain how lipids can control immune response

When we consume fats (also called lipids) in our diet, they can be metabolized or stored to provide energy for the body. But they are also involved in regulating the genes expressed within—and the signaling between—cells. Lipids influence how our cells behave and function, which affects many processes in the body including the immune system.

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Artificial sweeteners found to kill off antibiotic-resistant bacteria

Sugar substitutes found in many supermarket foods have been shown to kill off antibiotic-resistant bacteria that cause pneumonia and sepsis. Three artificial sweeteners used in products such as diet drinks, yogurts and desserts dramatically halt the growth of multidrug-resistant priority pathogens.

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 10:10am

Bacteria that break down nicotine found in the guts of mice

A team of researchers, has isolated a type of bacteria in the guts of mice that break down nicotine. In their paper published in the journal Nature, the group describes how they isolated the bacteria and why their finding could reduce incidences of fatty liver disease in humans.

Prior research has shown that smoking cigarettes is the leading cause of preventable deaths around the world. In addition to its association with lung disease, smoking cigarettes has also been linked to fatty liver disease. In this new effort, the researchers have found that a certain kind of bacteria breaks down nicotine in the guts of mice (due to forced smoking), and thereby reduces the likelihood of developing fatty liver disease.

When people (or mice) smoke cigarettes, it has been found, some of the nicotine makes its way into the gut, leading to an increased risk of fatty liver disease, associated with scarring, and in some cases, liver cancer.

In this new work, the researchers measured the amount of nicotine that makes its way to the gut by comparing stool samples of 30 human smokers and 30 nonsmokers. They then did the same with mice and found the results to be similar.

Next, they sterilized the guts of several lab mice and ran the nicotine experiment again. They found that the mice with the sterilized guts had more nicotine in their systems, indicating that at least one type of gut bacteria was breaking down the nicotine. Then, by process of elimination, they were able to track down the bacteria (Bacteroides xylanisolvens) that was responsible for the breakdown—it was producing a type of enzyme that breaks down nicotine.

Prior research has shown that B xylanisolven also live in the human gut. The researchers next plan to study it and the enzymes it produces to find out if the enzyme can be produced commercially and given to smokers to reduce their chances of developing fatty liver disease and by extension, liver cancer.

More information: Bo Chen et al, Gut bacteria alleviate smoking-related NASH by degrading gut nicotine, Nature (2022). DOI: 10.1038/s41586-022-05299-4

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 10:05am

Scientists reveal first close-up look at bats' immune response to live infection

In a world first, scientists  have sequenced the response to viral infection in colony-bred cave nectar bats (Eonycteris spelaea) at single-cell resolution. Published in the journal Immunity, the findings contribute to insights into bat immunity that could be harnessed to protect human health.

Bats harbor many types of viruses. Even when they are infected with viruses deadly to humans, they show no notable signs or symptoms of disease. By understanding how bats' immune responses protect them from infections, we may find clues that will help humans to better combat viral infections.

And knowing how to better fight viral infections can aid in the development of treatments that will help us to be more bat-like—by falling sick less and aging better.

In this study, the scientists investigated bat immune responses to Malacca virus, a double-stranded RNA virus that uses bats as its natural reservoir. This virus also causes mild respiratory disease in humans.

The team used single-cell transcriptome sequencing to study lung immune responses to infections at the cellular level, identifying the different types of immune cells in bats—some of which are different from those in other mammals, including humans—and uncovering what they do in response to such viral infections.

They found that a type of white blood cell, called neutrophils, showed a very high expression of a gene called IDO1, which is known to play a role in mediating immune suppression in humans. The scientists think that IDO1 expression in cave nectar bats could play an important role in limiting inflammation following infection.

Researchers also found marked anti-viral gene signatures in white blood cells known as monocytes and alveolar macrophages, which—in a sense—consume viral particles and then teach T cells how to recognize the virus. This observation is interesting as it shows that bats clearly activate an immune response following infection despite showing few outward symptoms or pathology. The team also identified an unusual diversity and abundance of T cells and natural killer cells—named for their ability to kill tumor cells and cells infected with a virus—in the cave nectar bat, which are broadly activated to respond to the infection.

Akshamal M. Gamage et al, Single-cell transcriptome analysis of the in vivo response to viral infection in the cave nectar bat Eonycteris spelaea, Immunity (2022). DOI: 10.1016/j.immuni.2022.10.008

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 9:29am

New CRISPR-based tool inserts large DNA sequences at desired sites in cells

Building on the CRISPR gene-editing system, researchers have designed a new tool that can snip out faulty genes and replace them with new ones, in a safer and more efficient way.

Using this system, the researchers showed that they could deliver genes as long as 36,000 DNA base pairs to several types of human cells, as well as to liver cells in mice. The new technique, known as PASTE, could hold promise for treating diseases that are caused by defective genes with a large number of mutations, such as cystic fibrosis.

The new tool combines the precise targeting of CRISPR-Cas9, a set of molecules originally derived from bacterial defense systems, with enzymes called integrases, which viruses use to insert their own genetic material into a bacterial genome.

Just like CRISPR, these integrases come from the ongoing battle between bacteria and the viruses that infect them. 

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The CRISPR-Cas9 gene editing system consists of a DNA-cutting enzyme called Cas9 and a short RNA strand that guides the enzyme to a specific area of the genome, directing Cas9 where to make its cut. When Cas9 and the guide RNA targeting a disease gene are delivered into cells, a specific cut is made in the genome, and the cells' DNA repair processes glue the cut back together, often deleting a small portion of the genome.

If a DNA template is also delivered, the cells can incorporate a corrected copy into their genomes during the repair process. However, this process requires cells to make double-stranded breaks in their DNA, which can cause chromosomal deletions or rearrangements that are harmful to cells. Another limitation is that it only works in cells that are dividing, as nondividing cells don't have active DNA repair processes.

This new work deals with a tool that could cut out a defective gene and replace it with a new one without inducing any double-stranded DNA breaks. To achieve this goal, they turned to a family of enzymes called integrases, which viruses called bacteriophages use to insert themselves into bacterial genomes.

For this study, the researchers focused on serine integrases, which can insert huge chunks of DNA, as large as 50,000 base pairs. These enzymes target specific genome sequences known as attachment sites, which function as "landing pads." When they find the correct landing pad in the host genome, they bind to it and integrate their DNA payload. Combining these enzymes with a CRISPR-Cas9 system that inserts the correct landing site would enable easy reprogramming of the powerful insertion system.

The new tool, PASTE (Programmable Addition via Site-specific Targeting Elements), includes a Cas9 enzyme that cuts at a specific genomic site, guided by a strand of RNA that binds to that site. This allows them to target any site in the genome for insertion of the landing site, which contains 46 DNA base pairs. This insertion can be done without introducing any double-stranded breaks by adding one DNA strand first via a fused reverse transcriptase, then its complementary strand.

Once the landing site is incorporated, the integrase can come along and insert its much larger DNA payload into the genome at that site.

Omar Abudayyeh, Drag-and-drop genome insertion of large sequences without double-strand DNA cleavage using CRISPR-directed integrases, Nature Biotechnology (2022). DOI: 10.1038/s41587-022-01527-4. www.nature.com/articles/s41587-022-01527-4

Comment by Dr. Krishna Kumari Challa on November 25, 2022 at 9:21am

Researchers suggest that wormholes may look almost identical to black holes

A group of researchers  has found evidence that suggests the reason that a wormhole has never been observed is that they appear almost identical to black holes.

They describe studying theoretical linear polarization from an accretion disk that would be situated around a class of static traversable wormholes and compared the findings to images of black holes.

For many years, scientists and science fiction writers have considered the theoretical possibility of a wormhole. Such an object, theory suggests, would take the form of a tunnel of sorts that connects two different parts of the universe. Moving through the tunnel would allow for travel to distant destinations in ways not available to spaceships incapable of moving faster than the speed of light—by taking a shortcut.

Unfortunately, no one has ever observed a worm hole or even any physical evidence that they actually exist. Still, because the theory for their existence is so strong, astrophysicists assume they do exist. The problem is that we either lack the technology to see them, or we have not been looking for them in the right way.

In this new effort, the researchers suggest that the latter is the problem. They have found evidence, via theory, that suggests that they might be sitting out there in the night sky in plain sight, and that the reason we are not seeing them is because we are mistaking them for black holes.

The work involved studying wormhole theories and then applying findings to the creation of simulations, with an emphasis on the polarity of the light that would be emitted by such an object—and by also taking account of the characteristics of an assumed disk surrounding its mouth. They then created both direct and indirect images to depict what a wormhole would look like and compared them to black holes; they found them to look remarkably similar.

The researchers noted that it should be possible to tell wormholes and black holes apart by noting subtle differences between them, such as polarization patterns and intensities and also their radii.

Valentin Deliyski et al, Polarized image of equatorial emission in horizonless spacetimes: Traversable wormholes, Physical Review D (2022). DOI: 10.1103/PhysRevD.106.104024

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

This, in turn, could have a long-term impact on coasts and islands, which are already suffering greatly under the weight of sea-level rise and erosion from increasingly frequent and powerful storm surges.

Marlena Joppien et al, Nanoplastic incorporation into an organismal skeleton, Scientific Reports (2022). DOI: 10.1038/s41598-022-18547-4

Marlena Joppien et al, Microplastics alter feeding strategies of a coral reef organism, Limnology and Oceanography Letters (2022). DOI: 10.1002/lol2.10237

Part2

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.
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