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Comment by Dr. Krishna Kumari Challa on September 12, 2021 at 12:38pm

Cannibalistic butterflies chow down on live caterpillars

For the first time, milkweed butterflies have been seen harassing, subduing and then slurping up the juices of caterpillars.

We generally think of butterflies s as beautiful, harmless, nectar-drinking insects. But new research carried out by the University of Sydney may change all that, as milkweed butterflies have been spotted scratching at caterpillars with their sharp claws to suck up their juices.

Milkweed butterflies are a group of butterflies in the Nymphalidae family, with one well-known species being the monarch butterfly.

As caterpillars, milkweed butterflies feed on toxic plants, using the chemicals as self-defence to make them unpalatable to birds and other predators. When the caterpillars turn into butterflies, they retain these toxins and advertise that they are poisonous with their bright colours.

Male butterflies will also use these toxic substances to produce mating pheromones. In order to boost their supplies of these love drugs, they’ll seek out extra sources of the chemicals.

Generally, they get these through plants, but in North Sulawesi, Indonesia, they have developed a taste for caterpillars – and they don’t care whether they are alive or dead.

“This is the first time the behaviour has been reported.

https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.3532

https://www.sciencefocus.com/news/cannibalistic-butterflies-chow-do...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 12:02pm

Animals shape shifting as climate warms

Some animals are "shape-shifting" and have developed bigger tails, beaks and ears to regulate their body temperatures as the planet warms, according to a new study. From Australian parrots to European rabbits, researchers found evidence that a host of warm-blooded animals have evolved bigger body parts, which could allow them to lose body heat more effectively. Climate change is heaping "a whole lot of pressure" on animals. It's high time we recognised that animals also have to adapt to these changes, but this is occurring over a far shorter timescale than would have occurred through most of evolutionary time. The study, published on recently  in the journal Trends in Ecology and Evolution, reviewed previous research "where climatic warming is a potential hidden explanatory variable for the occurrence of shape-shifting" and found trends particularly noticeable in birds.

The Australian parrot, for example, had shown an average 4-10 percent increase in the size of its bill since 1871 and the authors said this positively correlated with the summer temperature each year.

Other birds, like North American dark-eyed juncos, thrushes and Galapagos finches also saw bill size increases.

Meanwhile, the wings of the great roundleaf bat grew, the European rabbit developed bigger ears, while the tails and legs of masked shrews were found to be larger.

Shape-shifting does not mean that animals are coping with climate change and that all is 'fine'. It just means they are evolving to survive it -- but we're not sure what the other ecological consequences of these changes are, or indeed that all species are capable of changing and surviving.

It's well known that animals use their appendages to regulate their internal temperature. African elephants, for example, pump warm blood to their large ears, which they then flap to disperse heat.

The beaks of birds perform a similar function – blood flow can be diverted to the bill when the bird is hot. This heat-dispersing function shows the beak is warmer than the rest of the body. All this means there are advantages to bigger appendages in warmer environments.

warm-blooded animals – also known as endotherms – tended to have smaller appendages while those in warmer climates tend to have larger ones.

This pattern became known as Allen's rule, which has since been supported by studies of birds  and mammals.

Biological patterns such as Allen's rule can also help make predictions about how animals will evolve as the climate warms.

https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(21)00197-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS016953472100197X%3Fshowall%3Dtrue

https://researchnews.cc/news/8818/Animals--shape-shifting--as-clima...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:25am

What happens when two very different respiratory viruses infect the same cell

We know that several viruses infect us. A recent study from the University of Glasgow has discovered what happens when you get infected with some of these viruses at the same time, and it has implications for how they make us sick and how we protect ourselves from them.

For many reasons, respiratory viruses are often found during winter in the temperate regions of the world, or the rainy season of equatorial regions. During these periods, you'll probably be infected with more than one virus at any one time in a situation called a "co-infection."

Research shows that up to 30% of infections may harbor more than one virus. What this means is that, at some point two different viruses are infecting the cells that line your nose or lungs.

We know that co-infection can be important if we look at a process called "antigenic shift" in influenza viruses, which is basically caused by virus "sex." This sometimes occurs when two different influenza strains meet up inside the same cell and exchange genes, allowing a new variant to emerge.

Co-infection can create a predicament for viruses when you consider that they need to compete for the same resource: you. Some viruses appear to block other viruses, while some viruses seem to like each other. What is driving these positive and negative interactions during co-infections is unknown, but animal studies suggest that it could be critical in determining how sick you get.

The University of Glasgow study investigated what happens when you infect cells in a dish with two human respiratory viruses. For their experiments, they chose IAV and RSV, which are both common and cause lots of disease and death each year. The researchers looked at what happens to each virus using high-resolution imaging techniques, such as cryo-electron microscopy, that their labs have perfected over the years.

They found that some of the human lung cells in the dish contained both viruses. And, by looking closely at those co-infected cells, they found that the viruses that were emerging from the cell had structural characteristics of both IAV and RSV. The new "chimeric" virus particles had proteins of both viruses on their surface and some even contained genes from the other. This is the first evidence of this occurring from co-infection of distinct respiratory viruses.

Follow-up experiments in the same paper showed that these new chimeric viruses were fully functional and could even infect cells that were rendered resistant to influenza, presumably gaining access using the RSV proteins could even get into a broader range of human cells than either virus alone could. Potentially, this could be happening during natural co-infections during the winter.

https://www.biorxiv.org/content/10.1101/2021.08.16.456460v2

https://theconversation.com/heres-what-happens-when-two-very-differ...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:09am

Heliotropism evolves in response to highly specific environmental conditions, and factors affecting flowers can be different from those impacting leaves.

For example, flowers are all about pollination and seed production. For leaves, it's for maximizing photosynthesis, avoiding over-heating on a hot day or even reducing water loss in harsh and arid conditions.

Some species, such as the Queensland box, arrange their leaves so they're somewhat horizontal in the morning, capturing the full value of the available sunlight. But there are also instances where leaves align vertically to the sun in the middle of the day to minimize the risks of heat damage.

It's easy to think of plants as static organisms. But of course, they are forever changing, responding to their environments and growing. They are dynamic in their own way, and we tend to assume that when they do change, it will be at a very slow and steady pace.

Heliotropism shows us this is not necessarily the case. Plants changing daily can be a little unsettling in that we sense a change but may not be aware of what is causing our unease.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

https://phys.org/news/2021-09-daily-tracking-sun-fascinating.html?u...

Part2

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:08am

Why do some plants track the sun?

Heliotropism,  literally means moving in relation to the sun.

Sunflowers track the course of the sun spectacularly on warm and sunny, spring or summer days. Sometimes they move through an arc of almost 180⁰ from morning to evening.

A number flowering species display heliotropism, including alpine buttercups, arctic poppies, alfalfa, soybean and many of the daisy-type species. So why do they do it?

Flowers are really in the advertising game and will do anything they can to attract a suitable pollinator, as effectively and as efficiently as they can. There are several possible reasons why tracking the sun might have evolved to achieve more successful pollination.

By tracking the sun, flowers absorb more solar radiation and so remain warmer. The warmer temperature suits or even rewards insect pollinators that are more active when they have a higher body temperature.

Optimum flower warmth may also boost pollen development and germination, leading to a higher fertilization rate and more seeds.

So, the flowers are clearly moving. But how?

For many heliotropic flowering species, there's a special layer of cells called the pulvinus just under the flower heads. These cells pump water across their cell membranes in a controlled way, so that cells can be fully pumped up like a balloon or become empty and flaccid. Changes in these cells allow the flower head to move.

When potassium from neighboring plant cells is moved into the cells of the pulvinus, water follows and the cells inflate. When they move potassium out of the cells, they become flaccid.

These potassium pumps are involved in many other aspects of plant movement, too. This includes the opening and closing of stomata (tiny regulated leaf apertures), the rapid movement of mimosa leaves, or the closing of a fly trap.

In 2016, scientists discovered that the pin-up example of heliotropism—the sunflower—had a different way of moving.

They found sunflower movement is due to significantly different growth rates on opposite sides of the flowering stem.

On the east-facing side, the cells grow and elongate quickly during the day, which slowly pushes the flower to face west as the daylight hours go by—following the sun. At night the west-side cells grow and elongate more rapidly, which pushes the flower back toward the east over night.

Everything is then set for the whole process to begin again at dawn next day, which is repeated daily until the flower stops growing and movement ceases.

While many people are aware of heliotropism in flowers, heliotropic movement of leaves is less commonly noticed or known. Plants with heliotropic flowers don't necessarily have heliotropic leaves, and vice versa.

Part1

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 10:19am

 Study reveals that immune cells cooperate to trap and kill bacteria

Like a spider trapping its prey, our immune system cells cooperate to capture and "eat" bacteria.

The newly identified antibacterial mechanism, reported Sept. 10 in Science Advances, could inspire novel strategies for combating Staphylococcus aureus (staph) and other extracellular bacterial pathogens.

It was known that neutrophils—first responder immune cells that migrate to sites of infection—can self-destruct and release their protein and DNA contents to generate neutrophil extracellular traps (NETs). Now, Vanderbilt researchers led by postdoctoral fellow Andrew Monteith, Ph.D., have discovered that NETs boost the bacterial killing power of another type of immune cell: macrophages.

Neutrophils produce the spider webs that immobilize the bacteria, and macrophages are the spiders that engulf and kill the bacteria. Neutrophils and macrophages are both phagocytic cells known for ingesting bacteria and producing antimicrobial peptides, reactive oxygen species and other enzymes to fight infection. NET generation (NETosis), thought to be a form of programmed cell death, is a more recently discovered neutrophil antibacterial strategy. The released neutrophil DNA creates a sticky trap that is also studded with antimicrobial peptides.

The macrophages end up with not only their own antibacterial arsenal, but also the neutrophils' antibacterial arsenal, all in the same compartment killing the bacteria.

 Neutrophil extracellular traps enhance macrophage killing of bacterial pathogens, Science Advances (2021). DOI: 10.1126/sciadv.abj2101

https://phys.org/news/2021-09-caught-web-reveals-immune-cells.html?...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 9:21am

A new gold standard for detecting cancer mutations

An international research collaboration has identified a new gold standard for detecting cancer mutations using genomic pathology.

This research set out to understand why there has been a history of low reproducibility of genomic testing results between different labs when detecting cancers.

Scientists found factors like sample and library preparation, differing sequencing technology and bioinformatic tools were affecting the reproducibility and performance of the genomic analytical techniques.

The research team have now developed a set recommendations and guidelines on how to improve the reproducibility and precision of the tumor mutation detection in clinical practice.

All stages of mutation detection are interdependent and this dependency is complex.

There is no 'one way' to detect cancerous tumor mutations. For example, the amount of DNA sequencing needed to detect a cancer mutation will vary based on the amount of tumor content.

Every person is different and should be treated differently. And our research provides a new tool to improve precision medicine.

Wenming Xiao et al, Toward best practice in cancer mutation detection with whole-genome and whole-exome sequencing, Nature Biotechnology (2021). DOI: 10.1038/s41587-021-00994-5

https://medicalxpress.com/news/2021-09-gold-standard-cancer-mutatio...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 9:15am

First, the scientists investigated various cell lines to examine their gene expression levels of ACE2. They found that those cells originating in the oral cavity, lungs and liver had the highest ACE2 expression.

These high-ACE2-expression cells were then subjected to various doses of cigarette-smoke extract (CSE) for 24 hours. After this, the rate of expression of the CYP1A1 gene, which is known to be inducible by CSE, was evaluated. The CSE treatment had induced increased expression of CYP1A1 gene in liver and lung cells in a dose-dependent manner—the greater the dose, the greater the effect. However, this effect was not as pronounced in oral cavity cells. In other words, greater activity of the CYP1A1, less production of the ACE2 receptors—the route that the virus is able to enter cells.

In order to explain why this was happening in the presence of cigarette smoke, the researchers then used RNA sequencing analysis to investigate what was happening with gene expression more comprehensively. They found that CSE increased the expressions of genes related to a number of key signaling processes within the cell that are regulated by AHR.

To more directly observe this mechanism by which AHR acts on ACE2 expression, the effects of two drugs that can activate AHR were evaluated on the liver cells. The first, 6‑formylindolo(3,2‑b)carbazole (FICZ) is derivative of the amino acid tryptophan, and the second, omeprazole (OMP), is a medication already widely used in the treatment of acid reflux and peptic ulcers.

RNA sequencing data suggested that the CYP1A1 gene was strongly induced in liver cells by these AHR activators, and expression of the ACE2 gene was strongly inhibited, again in a dose-dependent manner.

In other words, the cigarette smoke extract and these two drugs—all of which act as activators of AHR—are able to suppress the expression of ACE2 in mammalian cells, and by doing so, reduce the ability of the SARS-CoV-2 virus to enter the cell.

Keiji Tanimoto et al, Inhibiting SARS-CoV-2 infection in vitro by suppressing its receptor, angiotensin-converting enzyme 2, via aryl-hydrocarbon receptor signal, Scientific Reports (2021). DOI: 10.1038/s41598-021-96109-w

https://medicalxpress.com/news/2021-09-drugs-mimic-effects-cigarett...

Part 2

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 9:14am

Drugs that mimic effects of cigarette smoke reduce SARS-CoV-2's ability to enter cells

Researchers have identified a potential reason why lower numbers of COVID cases have appeared amongst smokers compared to non-smokers, even as other reports suggest smoking increases severity of the disease.

Researchers have identified two drugs that mimic the effect of chemicals in cigarette smoke to bind to a receptor in mammalian cells that inhibits production of ACE2 proteins, a process that appears to reduce the ability of the SARS-CoV-2 virus to enter the cell.

The findings appear in the journal Scientific Reports on 17 August.

Something of a paradox exists with respect to smoking cigarettes and COVID-19. Active smoking is associated with increased severity of disease, but at the same time, many reports have suggested lower numbers of COVID cases amongst smokers than amongst non-smokers.

Something strange was going on here. We must stress the presence of strong evidence showing that smoking increases the severity of COVID-19. But the mechanism now discovered  is worth further investigation as a potential tool to fight SARS-CoV-2 infections.

--

It is known that cigarette smoke contains polycyclic aromatic hydrocarbons (PAHs). These can bind to and activate aryl hydrocarbon receptors (AHRs). A receptor is any structure of the surface or inside of a cell that is shaped to receive and bind to a particular substance. AHRs are a type of receptor inside of mammalian cells that is in turn a transcription factor—something that can induce a wide range of cellular activities through its ability to increase or decrease the expression of certain genes.

Knowing this about the relationship between PAHs and AHRs, the researchers wanted to investigate the effect of drugs that activate AHR on expression of the genes that control production of the ACE2 protein—the infamous receptor protein on the surface of many cells types that works like a lock that the SARS-CoV-2 virus is able to pick. After binding the virus to the ACE2 protein, it can then enter and infect the cell.

Part 1

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 9:07am

Study: AI can make better clinical decisions than humans

There's no harm in getting a second opinion. But what if that second opinion could be generated by a computer, using artificial intelligence? Would it come up with better treatment recommendations than your professional proposes?

Medical and educational professionals frequently disagree on the effectiveness of behavioral interventions, which may cause people to receive inadequate treatment.

To find a better way, researchers compiled simulated data from 1,024 individuals receiving treatment for behavioral issues. The researchers then compared the treatment conclusions drawn in each case by five doctoral-level behavior analysts with those produced by a computer model the two academics developed using machine learning.

The five professionals only came to the same conclusions approximately 75 percent of the time. More importantly, machine learning produced fewer decision-making errors than did all the professionals.

Given these very positive results, the next step would be to "integrate these models in an app that could automatically make decisions or provide feedback about how treatment is progressing". 

The goal, the researchers think, should be to use machine learning to facilitate the work of professionals, not actually replace them, while also making treatment decisions more consistent and predictable.

 Marc J. Lanovaz et al, Machine learning to analyze single‐case graphs: A comparison to visual inspection, Journal of Applied Behavior Analysis (2021). DOI: 10.1002/jaba.863

https://techxplore.com/news/2021-09-ai-clinical-decisions-humans.ht...

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