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Comment by Dr. Krishna Kumari Challa on March 1, 2021 at 10:11am

Caterpillar silences tomato's cry for help, scientists find

"Silencing the alarm."

Scientists found that a caterpillar called the tomato fruit worm not only chomps on tomatoes and their leaves, but also deposits enzyme-laden saliva on the plant, interfering with its ability to cry for help.

 It has been shown time and time again that when under attack, plants can emit chemical distress signals, causing their peers to mount some sort of defense. A classic example is the smell of a freshly mown lawn, which prompts the release of protective compounds in nearby blades of grass that have yet to be cut.

In some cases, plant distress signals can even summon help from other species. That's what happens with the tomato. When caterpillars nibble on the plant's leaves, the leaf pores release volatile chemicals that are detected by a type of parasite: a wasp that lays eggs inside caterpillars. 

So can the caterpillars strike back? In a series of experiments, researchers found that the answer was yes, illustrating a previously unknown strategy in nature's age-old contest between predator and prey.

The key is the enzyme in the caterpillar's saliva, which inhibits the opening of pores in tomato-plant leaves. That means the leaves are less able to release the distress signals, and presumably less able to attract wasps that could come to the rescue.

 Po‐An Lin et al. Silencing the alarm: an insect salivary enzyme closes plant stomata and inhibits volatile release, New Phytologist (2021). DOI: 10.1111/nph.17214

https://phys.org/news/2021-02-horror-movie-caterpillar-silences-tom...

Comment by Dr. Krishna Kumari Challa on March 1, 2021 at 9:56am

Researchers find a single-celled slime mold with no nervous system that remembers food locations

Having a memory of past events enables us to take smarter decisions about the future. Researchers now identified the basis for forming memories in the slime mold Physarum polycephalum—despite its lack of a nervous system.

The ability to store and recover information gives an organism a clear advantage when searching for food or avoiding harmful environments, and has been traditionally linked to organisms that have a nervous system. A new study challenges this view by uncovering the surprising abilities of a highly dynamic,single-celled organism to store and retrieve information about its environment.

The slime mold Physarum polycephalum has been puzzling researchers for many decades. Existing at the crossroads between the kingdoms of animals, plants and fungi, this unique organism provides insight into the early evolutionary history of eukaryotes. Its body is a giant single cell made up of interconnected tubes that form intricate networks. This single amoeba-like cell may stretch several centimeters or even meters, featuring as the largest cell on earth in the Guinness Book of World Records.

The striking abilities of the slime mold to solve complex problems such as finding the shortest path through a maze earned it the attribute "intelligent," intrigued the research community and kindled questions about decision making on the most basic levels of life. The decision-making ability of Physarum is especially fascinating given that its tubular network constantly undergoes fast reorganization—growing and disintegrating its tubes—while completely lacking an organizing center. The researchers discovered that the organism weaves memories of food encounters directly into the architecture of the network-like body and uses the stored information when making future decisions.

Researchers followed the migration and feeding process of the organism and observed a distinct imprint of a food source on the pattern of thicker and thinner tubes of the network long after feeding. Given P. polycephalum's highly dynamic network reorganization, the persistence of this imprint sparked the idea that the network architecture itself could serve as memory of the past.

The researchers combined microscopic observations of the adaption of the tubular network with theoretical modeling. An encounter with food triggers the release of a chemical that travels from the location where food was found throughout the organism and softens the tubes in the network, making the whole organism reorient its migration towards the food.

The gradual softening is where the existing imprints of previous food sources come into play and where information is stored and retrieved. Past feeding events are embedded in the hierarchy of tube diameters, specifically in the arrangement of thick and thin tubes in the network. For the softening chemical that is now transported, the thick tubes in the network act as highways in traffic networks, enabling quick transport across the whole organism. Previous encounters imprinted in the network architecture weigh into the decision about the future direction of migration.

Mirna Kramar et al. Encoding memory in tube diameter hierarchy of living flow network, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2007815118

https://phys.org/news/2021-02-single-celled-slime-mold-nervous-food...

Comment by Dr. Krishna Kumari Challa on February 28, 2021 at 12:24pm

X-factor to help antibiotics regain their spark

Comment by Dr. Krishna Kumari Challa on February 27, 2021 at 10:07am

How an ancient virus spread the ability to remember

A protein in your brain behaves like a virus, infecting your cells with memories

Forming a protective shell, Arc moves from neuron to neuron

Comment by Dr. Krishna Kumari Challa on February 27, 2021 at 9:21am

Study suggests habitat loss is leading to inbreeding of Indian tigers

While Indian tigers have the highest genetic variation compared to other subspecies of the feline across the world, their populations continue to be fragmented by loss of habitat, leading to inbreeding and potential loss of this diversity, says a new study.

 Habitat loss from human activities leads to tigers being "hemmed into their own protected area. Now, they can only mate with the other tigers in their own population. Over time, this will result in inbreeding, they will end up mating with their relatives. This  inbreeding might compromise their fitness and their ability to survive.

While genetic diversity across a population improves their chances of survival in the future, the study said population fragmentation of tigers can decrease this variation, and endanger them further.

https://academic.oup.com/mbe/advance-article/doi/10.1093/molbev/msa...

In the study, the scientists sequenced whole genomes from 65 individual tigers from four subspecies of the feline, and conducted a variety of population genomic analyses that quantify genetic variability. They investigated the partitioning of genetic variation, possible impacts of inbreeding, and demographic history, and possible signatures of local adaptation.

While the total genomic variation in Indian tigers was higher than in other subspecies, the study found that several individual tigers in the country had low variation, suggesting possible inbreeding.

https://www.thehindu.com/sci-tech/energy-and-environment/study-sugg...

Comment by Dr. Krishna Kumari Challa on February 27, 2021 at 8:37am

https://www.youtube.com/watch?v=mwr-wF_IMeU

https://www.youtube.com/watch?v=9nzkF0hmy04

https://www.youtube.com/watch?v=I1Bdp2tMFsY

Comment by Dr. Krishna Kumari Challa on February 27, 2021 at 8:31am

Scientists use Doppler to peer inside cells

Doppler radar improves lives by peeking inside air masses to predict the weather. A Purdue University team is using similar technology to look inside living cells, introducing a method to detect pathogens and treat infections in ways that scientists never have before.

In a new study, the team used Doppler to sneak a peek inside cells and track their metabolic activity in real time, without having to wait for cultures to grow. Using this ability, the researchers can test microbes found in food, water, and other environments to see if they are pathogens, or help them identify the right medicine to treat antibiotic-resistant bacteria.

Researchers worked with immortalized cell lines—cells that will live forever unless you kill them. They exposed the cells to different known pathogens, in this case salmonella and E. coli. They then used the Doppler effect to spy out how the cells reacted. These living cells are called "sentinels," and observing their reactions is called a biodynamic assay.

This strategy is broadly applicable when scientists have isolated an unknown microbe and want to know if it is pathogenic—harmful to living tissues—or not. Such cells may show up in food supply, water sources or even in recently melted glaciers.

Another benefit is the ability to quickly and directly diagnose which bacteria respond to which antibiotics.

 Honggu Choi et al, Doppler imaging detects bacterial infection of living tissue, Communications Biology (2021). DOI: 10.1038/s42003-020-01550-8

https://phys.org/news/2021-02-scientists-doppler-peer-cells.html?ut...

Comment by Dr. Krishna Kumari Challa on February 27, 2021 at 7:25am

Were it not for humans, woolly mammoths would have lived for 4,000 more years, simulation shows

An international team of researchers has used computer simulations to show that it was likely a combination of climate change and human hunting that led to the extinction of the woolly mammoth. They have written a paper describing their findings, available on the bioRxiv preprint server—in it, they suggest that were it not for human hunters, the mammoths would have lasted another 4,000 years.

the researchers created a simulation showing wooly mammoth populations from approximately 21,000 years ago, to 4,000 years ago—the time when the last of the mammoths died out. To recreate conditions the mammoths faced, the researchers added climate data as well as known human hunting data. They ran their simulation over 90,000 times with slight changes to the factors that might have led to their demise. The simulations showed that the most likely scenario involved climate change pushing the mammoths into smaller environments and hunters finishing them off. Interestingly, the researchers also found that if they removed human hunters from the simulations, the majority of the mammoths held on for another 4,000 years.

 Damien A. Fordham et al. Humans hastened the range collapse and extinction of woolly mammoth, bioRxiv (2021). DOI: 10.1101/2021.02.17.431706

https://phys.org/news/2021-02-humans-woolly-mammoths-years-simulati...

Comment by Dr. Krishna Kumari Challa on February 26, 2021 at 12:06pm

Microscopic Wrinkles in Leaves Ward Off Bugs

Crops have advanced a formidable vary of methods to beat back hungry, leaf-chomping bugs. Properly-known defenses embrace foul-tasting toxins, sticky resins and sharp thorns, and now scientists have recognized one more instance: microscopic wrinkles that make leaves more durable to stroll on.

Wrinkles kind in lots of leaves’ cuticles—coatings that restrict water evaporation, mediate gasoline alternate, and shield the plant from pathogens. The brand new analysis, revealed in Royal Society Open Science, finds that together with the cuticle’s inherently slippery floor, its tiny wrinkles additionally assist discourage bugs. The wrinkles most certainly grow to be extra pronounced because the leaf matures and its cuticle builds up, ultimately increasing and buckling.

https://royalsocietypublishing.org/doi/10.1098/rsos.201319

Comment by Dr. Krishna Kumari Challa on February 26, 2021 at 11:51am

Dancing Roots

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