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Comment by Dr. Krishna Kumari Challa on April 3, 2021 at 7:57am

Don’t go near water bodies that are coloured because study found airborne release of toxin from algal scum

A dangerous toxin has been witnessed—for the first time—releasing into the air from pond scum, research published in the peer-reviewed journal Lake and Reservoir Management recently shows.

Not only is pond scum—otherwise known as algal bloom—an unsightly formation which can occur on still water across the world, it can also prove dangerous to wildlife and humans.

For the first time, scientists have now detected the presence of the algal toxin anatoxin-a (ATX)which is also known as 'Very Fast Death Factor', in the air near ponds with large algal blooms. ATX can cause a range of symptoms at acute doses, including loss of coordination, muscular twitching and respiratory paralysis, and has been linked to the deaths of livestock, waterfowl and dogs from drinking contaminated water.

ATX is produced by single celled organisms known as cyanobacteria, which can form harmful algal blooms—when huge amounts of cyanobacteria grow in lake surface waters. Blooms are exacerbated by fertilizer run-off entering lakes or ponds from nearby fields or improperly treated wastewater, and can stimulate growth and high water temperatures. Cyanobacteria, which also are known as blue-green algae, are actually a type of bacteria that can photosynthesize.

Cyanobacterial blooms can also lead to low oxygen conditions, further degrading water quality. This is because when the algae in these large blooms die, they sink to the lake bottom and decompose, which can use up all the oxygen in the water, killing fish and other animals. The blooms also can release toxins into the water that can prove fatal for these animals.

ATX is one of the more dangerous cyanotoxins produced by harmful algal blooms, which are becoming more predominant in lakes and ponds worldwide due to global warming and climate change.People often recreate around these lakes and ponds with algal blooms without any awareness of the potential problems. Direct contact or inhalation of these cyanotoxins can present health risks for individuals, and researchers have reported a potential human health exposure not previously examined.

The detection of airborne anatoxin-a (ATX) on glass fiber filters during a harmful algal bloom, Lake and Reservoir Management (2021). DOI: 10.1080/10402381.2021.1881191

https://phys.org/news/2021-04-airborne-toxin-algal-scum.html?

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Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 11:49am

Butterflies -2

Martins, a former National Geographic Emerging Explorer, wrote about Charaxes, or emperor butterflies, in Swara magazine, published in East Africa where he is now Director of Kenya’s Mpala Research Centre.

“They are fast and powerful,” he writes. “And their tastes run to stronger stuff than nectar: fermenting sap, fresh dung and rotting carrion are all particular favourites.”

That’s right; don’t get between a butterfly and a freshly dropped pile of dung. It drives them wild. They uncoil their probosces and slurp away, lapping up the salts and amino acids they can’t get from plants.

It’s called mud-puddling, and it’s very common butterfly behavior. It doesn’t have to be dung, although that’s always nice; you may see flocks of butterflies having a nip of a dead animal (as depicted in this diorama of butterflies eating a piranha), drinking sweat or tears, or just enjoying a plain old mud puddle.

Butterflies start life as caterpillars, which are far from harmless if you’re a tasty plant, and can be carnivorous. Some are even parasites: Maculinea rebeli butterflies trick ants into raising their young. The caterpillars make sounds that mimic queen ants, which pick them up and carry them into their colonies like the well-to-do being toted in sedan chairs. Inside, they are literally treated as royalty, with worker ants regurgitating meals to them and nurse ants occasionally sacrificing ant babies to feed them when food is scarce. Butterflies invented the ultimate babysitting con.

So, let’s review. Here are seven not-so-nice things butterflies are into:

• Getting drunk
• Fighting
• Eating meat
• Eating poop
• Drinking tears
• Tricking ants
• Raping pupae

https://www.nationalgeographic.com/science/article/butterflies-beha...

The dark truth about butterflies

All this time, butterflies have been living secret lives that most of us never notice. From getting drunk to eating poop and tricking ants into raising their young, here are a few lesser known facts about these beautiful (sometimes) cannibals.

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 11:48am

Butterflies Behaving Badly: What They Don’t Want You to Know

Butterflies have had us fooled for centuries. They bobble around our gardens, all flappy and floppy, looking so pretty with their shimmering colors.

But butterflies have a dark side. For one thing, those gorgeous colors: They’re often a warning. And that’s just the beginning. All this time, butterflies been living secret lives that most of us never notice.

Take this zebra longwing, Heliconius charithonia. It looks innocent enough. 

But it’s also famously poisonous, and its caterpillars are cannibals that eat their siblings. And that’s hardly shocking compared with its propensity for something called pupal rape.

Once you know that a pupa is the butterfly in its chrysalis—in between being a larva and an adult—then pupal rape is pretty much what it sounds like. As a female gets ready to emerge from her chrysalis, a gang of males swarms around her, jostling and flapping wings to push each other aside. The winner of this tussle mates with the female, but he’s often so eager to do so that he uses his sharp claspers to rip into the chrysalis and mate with her before she even emerges. Since the female is trapped in the chrysalis and has no choice in the matter, the term pupal rape came about, though some biologists refer to it more charitably as “forced copulation” or simply pupal mating.

One day in Kenya’s North Nandi forest, Dino Martins, an entomologist, watched a spectacular battle between two white-barred Charaxes. A fallen log was oozing fermenting sap, and while a fluffy pile of butterflies was sipping and slowly getting drunk, the two white-barred butterflies showed up and started a bar fight. Spiraling and slicing at one another with serrated wings, the fight ended with the loser’s shredded wings fluttering gently to the forest floor.

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 11:39am

A Visual Guide to the New Coronavirus Variants

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 9:58am

Hubble Shows Torrential Outflows from Infant Stars May Not Stop Them from Growing

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 8:59am

Physicists observe new phase in Bose-Einstein condensate of light pa...

About 10 years ago, researchers at the University of Bonn produced an extreme aggregate photon state, a single "super-photon" made up of many thousands of individual light particles, and presented a completely new light source. The state is called an optical Bose-Einstein condensate and has captivated many physicists ever since, because this exotic world of light particles is home to its very own physical phenomena. Researchers led by Prof. Dr. Martin Weitz, who discovered the super photon, and theoretical physicist Prof. Dr. Johann Kroha now report a new observation: a so-called overdamped phase, a previously unknown phase transition within the optical Bose-Einstein condensate. The study has been published in the journal Science.

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 8:54am

How brain cells repair their DNA reveals 'hot spots' of aging and disease

Neurons lack the ability to replicate their DNA, so they're constantly working to repair damage to their genome. Now, a new study by Salk scientists finds that these repairs are not random, but instead focus on protecting certain genetic "hot spots" that appear to play a critical role in neural identity and function.

The findings, published in the April 2, 2021, issue of Science, give novel insights into the genetic structures involved in aging and neurodegeneration, and could point to the development of potential new therapies for diseases such Alzheimer's, Parkinson's and other age-related dementia disorders.

"This research shows for the first time that there are sections of genome that neurons prioritize when it comes to repair.

Unlike other cells, neurons generally don't replace themselves over time, making them among the longest-living cells in the human body. Their longevity makes it even more important that they repair lesions in their DNA as they age, in order to maintain their function over the decades of a human life span. As they get older, neurons' ability to make these genetic repairs declines, which could explain why people develop age-related neurodegenerative diseases like Alzheimer's and Parkinson's.

To investigate how neurons maintain genome health, the study authors developed a new technique they term Repair-seq. The team produced neurons from stem cells and fed them synthetic nucleosides—molecules that serve as building blocks for DNA. These artificial nucleosides could be found via DNA sequencing and imaged, showing where the neurons used them to make repairs to DNA that was damaged by normal cellular processes. While the scientists expected to see some prioritization, they were surprised by just how focused the neurons were on protecting certain sections of the genome.

"Incorporation of a nucleoside analog maps genome repair sites in postmitotic human neurons" Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abb9032

https://medicalxpress.com/news/2021-04-brain-cells-dna-reveals-hot....

Comment by Dr. Krishna Kumari Challa on April 2, 2021 at 7:37am

DNA can be collected from air, scientists show for first time

Scientists have shown for the first time that DNA can be collected from the air. The finding could provide new techniques for forensics researchers, anthropologists, and even help in the understanding of the transmission of airborne diseases like COVID-19, they say.

The team looked at whether environmental DNA (eDNA) could be collected from air samples and used to identify animal species. Most similar studies to date have focused on the collection of eDNA from water.

But the new proof-of-concept study, published in the journal PeerJ, showed that airDNA sampling could successfully detect naked mole rat DNA and human DNA in the air.

They first took air samples from a room which had housed naked mole-rats, and then used existing techniques to check for DNA sequences within the sampled air.

Using this approach, the research team showed that airDNA sampling could successfully detect mole rat DNA within the animals’ housing and from the room itself. They also found human DNA in the air samples, suggesting a potential use of this sampling technique for forensic applications.

https://peerj.com/articles/11030/

https://www.sciencefocus.com/news/dna-can-be-collected-from-air-sci...

Comment by Dr. Krishna Kumari Challa on April 1, 2021 at 10:08am

Here’s why humans chose particular groups of stars as constellations

Scientists simulate how humans trace patterns in the night sky

Stargazers can easily pick out the shape of a constellation. Now, scientists have shown that three factors can explain why certain groups of stars form such recognizable patterns.

To replicate how humans perceive the celestial sphere, a team of researchers considered how the eye might travel randomly across this night sky. Human eyes tend to move in discrete jumps, called saccades (SN: 10/31/11), from one point of interest to another. Scientists created a simulation that incorporated the distribution of lengths of those saccades, combined that with basic details of the night sky as seen from Earth — namely the apparent distances between neighboring stars and their brightnesses. The technique could reproduce individual constellations.

Ancient people from various cultures connected similar groupings of stars independently of each other. this indicates that there are some fundamental aspects of human learning … that influence the ways in which we organize information.

S. David et al. Free energy model of the human perception of a starry sky. American Physical Society March Meeting. March 18, 2021.

Comment by Dr. Krishna Kumari Challa on April 1, 2021 at 9:29am

Neuroscientists have identified a brain circuit that stops mice from mating with others that appear to be sick

When someone is sick, it's natural to want to stay as far from them as possible. It turns out this is also true for mice, according to an MIT study that also identified the brain circuit responsible for this distancing behaviour.

In a study that explores how otherwise powerful instincts can be overridden in some situations, researchers from MIT's Picower Institute for Learning and Memory found that when male mice encountered a female mouse showing signs of illness, the males interacted very little with the females and made no attempts to mate with them as they normally would. The researchers also showed that this behavior is controlled by a circuit in the amygdala, which detects distinctive odors from sick animals and triggers a warning signal to stay away.

Earlier  studies have shown that mice can distinguish between healthy mice and mice that have been injected with a bacterial component called LPS, which induces mild inflammation when given at a low dose. These studies suggested that mice use odor, processed by their vomeronasal organ, to identify sick individuals.

To explore whether mice would change their innate behavior when exposed to sick animals, the researchers placed male mice in the same cage with either a healthy female or a female that was showing LPS-induced signs of illness. They found that the males engaged much less with the sick females and made no effort to mount them.

The researchers then tried to identify the brain circuit underlying this behavior. The vomeronasal organ, which processes pheromones, feeds into a part of the amygdala called the COApm, and the MIT team found that this region is activated by the presence of LPS-injected animals.

Further experiments revealed that activity in the COApm is necessary to suppress the males' mating behavior in the presence of sick females. When COApm activity was turned off, males would try to mate with sick females. Additionally, artificially stimulating the COApm suppressed mating behavior in males even when they were around healthy females.

 An amygdala circuit that suppresses social engagement, Nature (2021). DOI: 10.1038/s41586-021-03413-6

https://phys.org/news/2021-03-neuroscientists-brain-circuit-mice-si...

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