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Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 10:35am

Resistance to last-resort antibiotic may be passing between pet dogs and their owners

The dangerous mcr-1 gene, which provides resistance to the last-resort antibiotic colistin, has been found in four healthy humans and two pet dogs. In two cases, both dog and owner were harbouring the gene, according to new research being presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) held online this year.

Since first being reported in China in 2015, the mcr-1 gene has been found in various people and animals around the world. It confers resistance to colistin, an antibiotic of last resort used to treat infections from some bacteria resistant to all other antibiotics. The nightmare scenario that could emerge is mcr-1 combining with already drug-resistant bacteria to create a truly untreatable infection.

The study showed that eight dogs out of the 102 pets (7.8%) and four humans out of 126 (3.2%) harboured bacteria with the mcr-1 gene. Three of the dogs were healthy, four had SSTIs and one had a UTI. None of the cats were carrying the gene.

Further analysis showed that the bacteria isolated from all 12 samples that were mcr-1 positive were resistant to multiple antibiotics.

In two households with dogs with SSTIs, the mcr-1 gene was found in both dog and owner. Genetic analysis of the samples suggested that in one of these two cases, the gene had been transmitted between pet and owner.While transmission in both directions is possible, it is thought that in this case the gene passed from dog to human, say the researchers.

The owners did not have infections and so did not need treatment. The sick dogs were successfully treated.

The researchers say their results show that the mcr-1 gene can be transmitted between dogs and their owners. This raises concerns that pets can act as reservoirs of the gene and so aid the spread of resistance to precious last-line antibiotics.

The study was presented at the ongoing European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) taking place online between July 9 and 12.

Source: EUROPEAN SOCIETY OF CLINICAL MICROBIOLOGY AND INFECTIOUS DISEASES

https://medicalxpress.com/news/2021-07-resistance-last-resort-antib...

Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 9:23am

Heritable Epigenetics: The right combination of parents can turn a gene off indefinitely

Evidence suggests that what happens in one generation—diet, toxin exposure, trauma, fear—can have lasting effects on future generations. Scientists think these effects result from epigenetic changes that occur in response to the environment and turn genes on or off without altering the genome or DNA sequence.

But how these changes are passed down through generations has not been understood, in part, because scientists have not had a simple way to study the phenomenon. A new study by researchers at the University of Maryland provides a potential tool for unraveling the mystery of how experiences can cause inheritable changes to an animal's biology. By mating nematode worms, they produced permanent epigenetic changes that lasted for more than 300 generations. The research was published on July 9, 2021, in the journal Nature Communications.

With their new findings, the researchers now think  some genes could be more vulnerable to permanent epigenetic change while other genes recover within a few generations. Although studies in worms are not the same as in humans, the research provides a window into biological processes that are likely shared, at least in part, by all animals.

"Mating can initiate stable RNA silencing that overcomes epigenetic recovery," Nature Communications (2021). DOI: 10.1038/s41467-021-24053-4

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The research team found while breeding nematode worms that some matings led to epigenetic changes in offspring that continued to be passed down through as many generations as the scientists continued to breed them. This discovery will enable scientists to explore how epigenetic changes are passed to future generations and what characteristics make genes susceptible to permanent epigenetic changes.

They found that there are these RNA-based signals controlling gene expression. Some of these signals silence the gene and some of them are protective signals that prevent silencing. These signals are duking it out as the offspring develop. When the gene comes from the mother, the protective signal always wins, but when the gene comes from the father, the silencing signal almost always wins.

When the silencing signal wins, the gene is silenced for good, or for at least 300 generations, which is how long these researchers followed their laboratory-bred worms. Previous examples of epigenetic changes were more complex or they did not last more than a couple of generations. The researchers don't yet know why the silencing signal only wins some of the time, but this new finding puts them in a much better position to explore the details of epigenetic inheritance than ever before.

While they've found a set of genes that can be silenced almost permanently, most other genes are not affected the same way.

https://phys.org/news/2021-07-combination-parents-gene-indefinitely...

Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 8:27am

Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 8:25am

Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 8:24am

Sulfhemoglobinemia

Comment by Dr. Krishna Kumari Challa on July 11, 2021 at 10:57am

Scientists Have Created a New Bendy And Flexible Form of Ice

Water ice isn't exactly known for its flexibility. In fact, it's quite the opposite: rigid and brittle, easily fracturing and snapping. It's why avalanches and sea ice fragmentation occur.

It's also why new research is so fascinating. Scientists have just grown microfibers of water ice that can bend in a loop – breaking the previous maximum strain by a significant percentage and opening up new opportunities for the exploration of ice physics.

Ice doesn't always behave the way we expect, and its elasticity – or rather, lack thereof – is a perfect example. Theoretically, it should have a maximum elastic strain of around 15 percent. In the real world, the maximum elastic strain ever measured was less than 0.3 percent. The reason for this discrepancy is that ice crystals have structural imperfections that drive up their brittleness.

So a team of researchers led by nanoscientist Peizhen Xu of Zhejiang University in China sought to create ice with as few structural imperfections as possible.

The experiment consisted of a tungsten needle in an ultracold chamber, sitting at around minus 50 degrees Celsius, much colder than has been previously attempted. Water vapor was released into the chamber, and an electric field was applied. This attracted water molecules to the tip of the needle, where they crystallized, forming a microfiber with a maximum width of around 10 micrometers,  smaller than the width of a human hair.

The next step was to lower the temperature to between minus 70 and minus150 degrees Celsius. Under these low temperatures, the researchers tried bending the ice fibers.

At minus 150 degrees Celsius, they found that a microfiber 4.4 micrometers across was able to bend into a nearly circular shape, with a radius of 20 micrometers. This suggests a maximum elastic strain of 10.9 percent – much closer to the theoretical limit than previous attempts.

Even better, when the researchers released the ice, it sprang back into its previous shape.

https://science.sciencemag.org/content/373/6551/187

https://www.sciencealert.com/scientists-have-created-a-new-bendy-an...

Comment by Dr. Krishna Kumari Challa on July 10, 2021 at 11:24am

Scientists reveal how cauliflowers develop their unique shape

 Have you ever wondered how a cauliflower grows into its strange shape? - The mystery of how this peculiar shaped vegetable forms has now been solved by a team of mathematicians and plant scientists.

Now a new study revealed that cauliflowers, and Romanescos in particular, are in fact buds that are designed to become flowers but which never reach their goal. The findings have been published in Science.

The research combines mathematical modelling and plant biology to show that instead of reaching flowering stage cauliflowers develop into stems, which in turn continue trying to produce flowers. The cauliflower is born from this chain reaction, resulting in a succession of stems upon stems.

This study shows that the brief incursion of buds into a flowering state profoundly affects their functioning and allows them, unlike normal stems, to grow without leaves and to multiply almost infinitely. The atypical shape of the Romanesco is explained by the fact that its stems produce buds more and more rapidly (whereas the production rate is constant in other cauliflowers). This acceleration gives each floret a pyramidal appearance, making the fractal aspect of the structure clear. The study highlights how the selection of mutations in plants during the process of domestication has changed their shape, sometimes drastically, into the fruits and vegetables on our shelves.

https://www.nottingham.ac.uk/news/scientists-reveal-how-cauliflower...

Although most plants present a geometric organisation in spirals along main and secondary axes (called "phyllotaxis"), cauliflowers present an unusual phyllotaxis with a multitude of spirals, nested over a wide range of scales. How such a fractal self-similar organization emerges from developmental mechanisms has, until now, remained elusive.

Combining experimental analyses in Arabidopsis thaliana cauliflower-like mutant with mathematical modelling, researchers found that curd self-similarity arises because growing plant tissues fail to form flowers but keep the “memory” of their transient passage in a floral state. Understanding this genetic mutation could help plant scientists optimise growth of related plants.

https://researchnews.cc/news/7684/Scientists-reveal-how-cauliflower...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 12:04pm

Biological fireworks show 300 million years in the making

Five years ago, researchers  discovered that human eggs, when fertilized by sperm, release billions of zinc ions, dubbed "zinc sparks."

They now found out that these same sparks fly from highly specialized metal-loaded compartments at the egg surface when frog eggs are fertilized. This means that the early chemistry of conception has evolutionary roots going back at least 300 million years, to the last common ancestor between frogs and people.

And the research has implications beyond this shared biology and deep-rooted history. It could also help shape future findings about how metals impact the earliest moments in human development. This work may help inform our understanding of the interplay of dietary zinc status and human fertility.

They also discovered that fertilized frog eggs eject another metal, manganese, in addition to zinc. It appears these ejected manganese ions collide with sperm surrounding the fertilized egg and prevent them from entering.

These breakthroughs support an emerging picture that transition metals are used by cells to regulate some of the earliest decisions in the life of an organism.

John F. Seeler et al, Metal ion fluxes controlling amphibian fertilization, Nature Chemistry (2021). DOI: 10.1038/s41557-021-00705-2

https://phys.org/news/2021-07-biological-fireworks-million-years.ht...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 11:58am

More cell phone data use is negatively affecting Wi-Fi performance, study finds

If service becomes slow when you're trying to send a quick email on your smartphone, you might scroll through your network options and discover how many Wi-Fi networks there are. In fact, this plethora of options is itself the problem. These networks are in competition with one another, limiting the speed at which each can operate.

Hidden-nodes in coexisting LAA & Wi-Fi: a measurement study of real deployments. arxiv.org/abs/2103.15591

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 11:11am

Stem cells can use same method as plants and insects to protect against viruses

Researchers at the Francis Crick Institute have found a vital mechanism, previously thought to have disappeared as mammals evolved, that helps protect mammalian stem cells from RNA viruses such as SARS-CoV-2 and Zika virus. The scientists suggest this could one day be exploited in the development of new antiviral treatments.

On infecting a host, a virus enters cells in order to replicate. For most cells in mammals the first line of protection are proteins, called interferons. Stem cells, however, lack the ability to trigger an interferon response and there has been uncertainty about how they protect themselves.

In their study, published in Science today the scientists analyzed genetic material from mouse stem cells and found it contains instructions to build a protein, named antiviral Dicer (aviD), which cuts up viral RNA and so prevents RNA viruses from replicating. This form of protection is called RNA interference, which is the method also used by cells in plants and invertebrates.

In laboratory experiments which exposed engineered human cells to SARS-CoV-2, the virus infected three times fewer stem cells when aviD was present in the cells compared to when the researchers removed this protein.

An isoform of Dicer protects mammalian stem cells against multiple RNA viruses" Science (2021). science.sciencemag.org/lookup/ … 1126/science.abg2264

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It's fascinating to learn how stem cells protect themselves against RNA viruses. The fact this protection is also what plants and invertebrates use suggests it might be something that goes far back in mammalian history, right up to when the evolutionary tree spilt. For some reason, while all mammalian cells possess the innate ability to trigger this process, it seems to only be relied upon by stem cells.

By learning more about this process, and uncovering the secrets of our immune system we are hoping to open up new possibilities for drug development as we strive to harness our body's natural ability to fight infection

The scientists also grew mini brain organoids from mouse embryonic stem cells and found that, when infected with Zika virus, the organoids with aviD grew more quickly and less viral material was produced than in organoids without this protein. Similarly, when organoids were infected with SARS-CoV-2, there were fewer infected stem cells in the organoids with aviD.

https://phys.org/news/2021-07-stem-cells-method-insects-viruses.htm...

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