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Comment by Dr. Krishna Kumari Challa on November 24, 2023 at 12:40pm

Study shows plants use air channels to create a directional light signal and regulate phototropism

Plants have no visual organs, so how do they know where light comes from? In an original study combining expertise in biology and engineering, scientists  uncovered that a light-sensitive plant tissue uses the optical properties of the interface between air and water to generate a light gradient that is "visible" to the plant. These results have been published in the journal Science.

The majority of living organisms (micro-organisms, plants and animals) have the ability to determine the origin of a light source, even in the absence of a sight organ comparable to the eye. This information is invaluable for orienting oneself or optimal positioning in the environment.

Perceiving where light is coming from is particularly important for plants, which use this information to position their organs, a phenomenon known as phototropism. This enables them to capture more of the sun's rays, which they then convert into chemical energy through the process of photosynthesis, a vital process that is necessary for the production of nearly all of the food we eat.

Although the photoreceptor that initiates phototropism has long been known, the optical properties of photosensitive plant tissue have until now remained a mystery. A multidisciplinary study uncovered a surprising tissue feature allowing plants to detect directional light cues.

Part 1

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 10:37am

Space Communication: beaming messages via laser

Beaming messages via laser across a distance of almost 16 million kilometers or 10 million miles is no longer fiction.

That's about 40 times farther than the Moon is from Earth, and it's the first time that optical communications have been sent across such a distance. Traditionally, we use radio waves to talk to distant spacecraft – but higher frequencies of light, such as near infrared, offer an increase in bandwidth and therefore a huge boost in data speed. If we're going to be able to send high-definition video messages to and from Mars without a significant delay, then this is the tech we need. The test is part of NASA's Deep Space Optical Communications (DSOC) experiment, and the successful establishment of the comms link is known as 'first light'.

https://www.jpl.nasa.gov/missions/deep-space-optical-communications...

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 8:39am

How to keep polio from coming back

Poliovirus is close to being eliminated: it could be gone within three years. But eradication is not extinction. The next challenge will be keeping it at bay. In rare cases, the oral poliovirus vaccine can itself seed a polio outbreak. But withdrawing that vaccine will leave people unprotected. The inactivated poliovirus vaccine doesn’t have the same flaw, but it doesn’t block transmission, so a broad vaccination programme would have to continue. And we will have to be sure that polio can never escape from a research institute or vaccine-manufacturing facility. Finally, a very tiny — but unknown — number of people have immune-deficiency disorders that mean they can carry and spread polio without knowing it, for years.

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Study uncovers no compelling evidence that air purifiers prevent re...

The COVID pandemic led to many calls for improved indoor air quality with claims that doing so would reduce the risk of the virus spreading. However, the real-world evidence to support these claims has been lacking, and studies undertaken during the pandemic have not yet been reported.

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 8:34am

Wi-Fi for nerve signals
Researchers have charted a long-distance ‘wireless’ nerve network in Caenorhabditis elegans worms for the first time. The nervous system can be thought of as a web of neurons that pass on messages through direct links, called synapses. But neurons can also communicate over longer distances by releasing molecules called neuropeptides, which are intercepted by other neurons some distance away. Incorporating both ‘wired’ synaptic connections and wireless signalling better predicts how signals travel in the worm than does a model using synaptic connections alone.

https://www.nature.com/articles/d41586-023-03619-w?utm_source=Live+...

Randi, F., Sharma, A. K., Dvali, S. & Leifer, A. M. Nature 623, 406–414 (2023).

Ripoll-Sánchez, L. et al. Neuron 111, 3570–3589 (2023).

Wang, H. et al. Science 382, eabq8173 (2023).

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 8:26am

Researchers pinpoint brain area where people who are blind recognize faces identified by sound

Using a specialized device that translates images into sound, neuroscientists  showed that people who are blind recognized basic faces using the part of the brain known as the fusiform face area, a region that is crucial for the processing of faces in sighted people.

It's been known for some time that people who are blind can compensate for their loss of vision, to a certain extent, by using their other senses.

This study tested the extent to which this plasticity, or compensation, between seeing and hearing exists by encoding basic visual patterns into auditory patterns with the aid of a technical device researchers refer to as a sensory substitution device. With the use of functional magnetic resonance imaging (fMRI), they can determine where in the brain this compensatory plasticity is taking place.

Face perception in humans and nonhuman primates is accomplished by a patchwork of specialized cortical regions. How these regions develop has remained controversial. Due to their importance for social behavior, many researchers think that the neural mechanisms for face recognition are innate in primates or depend on early visual experience with faces.

The new results  from people who are blind imply that fusiform face area development does not depend on experience with actual visual faces but on exposure to the geometry of facial configurations, which can be conveyed by other sensory modalities.

Josef Rauschecker et al, Sound-encoded faces activate the left fusiform face area in the early blind, PLoS ONE (2023). journals.plos.org/plosone/arti … journal.pone.0286512

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 8:16am

Careful histological and morphological observations revealed that the stolon formation starts with the maturation of gonads in the posterior end. Then forms a head in the anterior part of the developing stolon. Sense organs such as eyes and antennae, and swimming bristles form soon after. Before the stolon detaches, it develops nerves and a 'brain' to sense and behave independently.

To understand the development of stolon's head, researchers investigated the developmental gene expression patterns of the sexually maturing worms. A well-known group of head formation genes are known to define the head region of various animals. They found that these genes are expressed more in the head region of the stolon. Typically, the head formation genes are not expressed as much in the middle of the body. But during gonad development in syllids, head formation genes are highly expressed in the middle of the posterior end of the original body.

This shows how normal developmental processes are modified to fit the life history of animals with unique reproductive styles.

Morphological, Histological and Gene-Expression Analyses on Stolonization in the Japanese Green Syllid, Megasyllis nipponica (Annelida, Syllidae), Scientific Reports (2023). DOI: 10.1038/s41598-023-46358-8

Part 2

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 8:14am

This sea worm's posterior swims away, and now scientists know how

Life always finds ways to surprise us. The presence of a unique reproductive mechanism in some annelid worms or segmented worms is one such surprise. In a process called stolonization, the posterior body part with gonads of the syllid worm detaches from its original body. The detached part is called the stolon, and it is full of gametes (eggs or sperm).

The stolon swims around by itself and spawns when it meets the opposite sex. Swimming autonomously would not only protect the original body from environmental dangers but could also help its gametes disperse over larger distances.

To swim autonomously, the stolons develop their own eyes, antennae, and swimming bristles while still attached to their original body. But how does the stolon head form in the middle of the original body?

Part 1

Comment by Dr. Krishna Kumari Challa on November 23, 2023 at 7:58am

Chlorine disinfectant is no more effective than water at killing off hospital superbug, new study shows

One of the primary chlorine disinfectants currently being used to clean hospital scrubs and surfaces does not kill off the most common cause of antibiotic-associated sickness in health care settings globally, according to a new study.

Research has shown that spores of Clostridioides difficile, commonly known as C. diff, are completely unaffected despite being treated with high concentrations of bleach used in many hospitals. In fact, the chlorine chemicals are no more effective at damaging the spores when used as a surface disinfectant—than using water with no additives. Writing in the journal Microbiology, the study's authors say susceptible people working and being treated in clinical settings might be unknowingly placed at risk of contracting the superbug.

As a result, and with incidence of biocide overuse only serving to fuel rises in antimicrobial resistance (AMR) worldwide, they have called for urgent research to find alternative strategies to disinfect C. diff spores in order to break the chain of transmission in clinical environments.

 Clostridioides difficile spores tolerate disinfection with Sodium hypochlorite disinfectant and remain viable within surgical scrubs and gown fabrics, Microbiology (2023). DOI: 10.1099/mic.0.001418

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 12:32pm

During this research work, when the hatchlings emerged, researchers recorded their sex and tested them for 18 heavy metals like cadmium and chromium, plus organic pollutants like polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs).

These contaminants are all known or suspected to function as 'xenoestrogens' or molecules that bind to the receptors for female sex hormones. Female turtles accumulate these contaminants at their foraging sites. As eggs develop within her, they absorb the contaminants that she accumulated and sequester them in the liver of the embryos, where they can stay for years after hatching.

the study found varying sex ratios among the different clutches, but most nests yielded predominantly female hatchlings, the researchers report.

And the degree of female bias in each nest showed an association with xenoestrogen levels in the hatchlings, they discovered: higher pollutant levels in hatchlings' livers correlated with a greater female bias in their nest.

More research is still needed to clarify whether these pollutants are contributing to differences in sex ratio, but the association already warrants concern, researchers say.

https://www.frontiersin.org/articles/10.3389/fmars.2023.1238837/full

Part 2

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 12:29pm

The World Is Running Out of Male Sea Turtles

Green sea turtles are already an endangered species, mainly due to humans hunting them, harvesting their eggs, degrading their habitats, or entangling them in garbage (fishing nets) of some kind.

But they also face another, more insidious threat from people: the loss of male hatchlings from the species.

You probably already know that this is partly caused by rising temperatures due to climate change – but a new study has now unveiled another human-caused problem driving this trend.

Certain pollutants may promote feminization in sea turtles. New research work  shows that the risk of extinction due to a lack of male green sea turtles may be compounded by contaminants that may also influence the sex ratio of developing green sea turtles, increasing the bias towards females.

Green sea turtles (Chelonia mydas) have a vast geographical range, inhabiting tropical, subtropical, and temperate regions of the Atlantic, Pacific, and Indian oceans, as well as the Mediterranean Sea.

Male hatchlings are now heavily outnumbered by females overall, although the degree of imbalance varies in different parts of their range. In some warmer places like the northern Great Barrier Reef, researchers say, hundreds of female turtles are now born for every male.

That's because sea turtles use temperature-dependent sex determination, meaning an embryo's sex is determined by sand temperatures around its egg in the nest, with warmer sand favoring females. As temperatures rise around the world, male hatchlings are growing scarce. But that's not the only factor involved in determining sex, the latest research suggests.

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