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Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 11:09am

Nanomaterials may enhance plant tolerance to high soil salt levels

Soil salt concentrations above the optimal threshold for plant growth can threaten global food security by compromising agricultural productivity and crop quality. An analysis published in Physiologia Plantarum has examined the potential of nanomaterials—which have emerged over the past decade as a promising tool to mitigate such "salinity stress"—to address this challenge.

Nanomaterials, which are tiny natural or synthetic materials, can modulate a plant's response to salinity stress through various mechanisms, for example by affecting the expression of genes related to salt tolerance or by enhancing physiological processes such as antioxidant activities.
When investigators assessed 495 experiments from 70 publications related to how different nanomaterials interact with plants under salinity stress, they found that nanomaterials enhance plant performance and mitigate salinity stress when applied at lower dosages. At higher doses, however, nanomaterials are toxic to plants and may even worsen salinity stress.

Also, plant responses to nanomaterials vary across plant species, plant families, and nanomaterial types.

Meta-analysis of nanomaterials and plants interaction under salinity stress, Physiologia Plantarum (2024). DOI: 10.1111/ppl.14445

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 11:05am

Processing traumatic memories during sleep leads to changes in the brain associated with improvement in PTSD symptoms

Currently, the first-choice treatment for PTSD is exposure-based psychotherapy, where therapists help rewire the emotions associated with the traumatic memory in the patient's brain, shifting from fear and arousal to a more neutral response.

PTSD is a mental health disorder that can occur after experiencing or witnessing a traumatic event. People with PTSD may experience flashbacks, nightmares, heightened vigilance, hyper-arousal, and mood and sleep problems. Currently available treatments for PTSD include eye movement desensitization and reprocessing (EMDR), where therapists guide patients through their traumatic memories while using a moving light or clicking sounds to distract them.

However, up to 50% of patients fail to respond well to this treatment.

EMDR has shown positive results, but  that success is low and dropping out from the treatment program is common among patients because revisiting traumatic memories is emotionally demanding.

In a study published on August 7 in Current Biology, scientists show for the first time that reactivating therapeutically-altered memories during sleep leads to more brain activity related to memory processing, which is associated with a reduction in PTSD symptoms.

Sleep provides a unique opportunity to enhance the memory of newly formed emotional reactions to traumatic events. During sleep, the brain focuses on consolidating memories and storing information for the long term.

Previous research has shown that if someone forms a new memory in the presence of an experimentally administered sound or scent, exposing them to the sound or scent while they sleep can improve their ability to recall that memory after waking up. This memory-enhancement technique is called targeted memory reactivation (TMR).

TMR has no negative effects on these patients. None of the patients reported more nightmares or worsened sleep after TMR.

Many psychiatric disorders, such as phobias, anxiety disorders, and addiction, are also related to maladaptive memories. This new work can inspire future research to explore the beneficial effects of TMR in treating other conditions.

Targeted memory reactivation to augment treatment in post-traumatic stress disorder, Current Biology (2024). DOI: 10.1016/j.cub.2024.07.019. www.cell.com/current-biology/f … 0960-9822(24)00922-9

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 10:55am

DNA fragments help detect kidney organ rejection

Findings from a study published in Nature Medicine show that donor-derived cell-free DNA (dd-cfDNA), also called liquid biopsy, has the potential for early detection of kidney transplant rejection.

The international study enrolled a diverse population of nearly 3,000 kidney transplant recipients—both adult and pediatric—from 14 transplantation centers in Europe and the U.S. The Department of Pediatrics at Washington University School of Medicine in St. Louis contributed one of the two pediatric datasets involved in the study.
When cells undergo apoptosis or necrosis, they release small fragments of DNA, known as cell-free DNA (cf-DNA), into the bloodstream. In inflammation associated with transplant rejection, dying cells release donor-derived cell-free DNA (dd-cfDNA). Researchers found those dd-cfDNA levels were strongly correlated with different types of transplant rejection, including antibody-mediated rejection, T cell-mediated rejection and mixed rejection. The study found similar accuracy in children and adults.

Often unnecessary and invasive graft biopsies are currently considered the "gold standard" in diagnosing transplant rejection, but dd-cfDNA could provide a non-invasive, accurate biomarker to reduce the need for biopsy.

While biopsies will continue as the method of rejection diagnosis, dd-cfDNA may improve early rejection diagnosis and enhance the care of kidney transplant recipients.

Olivier Aubert et al, Cell-free DNA for the detection of kidney allograft rejection, Nature Medicine (2024). DOI: 10.1038/s41591-024-03087-3

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 10:48am

Bacterial gut diversity improves the athletic performance of racehorses

The composition of gut bacteria of thoroughbred racehorses at one month old can predict their future athletic performance, according to a new study. 

In the study, foals with lower bacterial diversity at 28 days old also had a significantly increased risk of respiratory disease later in life.

This study is published in the journal Scientific Reports.

Researchers from Surrey's School of Veterinary Medicine and School of Bioscience 

investigated the composition of gut bacteria in thoroughbred foals bred for flat racing and its impact on their long-term health and athletic performance.

To investigate this, 438 fecal samples from 52 foals were analyzed, and respiratory, gastrointestinal, orthopedic and soft-tissue health issues were tracked from birth to age three. In addition, the team analyzed information regarding finishing position, official rating, and total prize money earnings as measures of athletic performance.

Minimizing the risk of disease and injury is important for the welfare of racehorses, and maximizing their athletic potential is important for their owners. Researchers have now found that gut health, in particular the health of gut bacterial communities very early in life, exerts a profound and enduring impact on racehorse health and performance.

Researchers found that the athletic performance of the foals was positively associated with higher fecal bacterial diversity at one month old. They identified that a higher abundance of the bacteria Anaeroplasmataceae was associated with a higher official rating (an evaluation of a horse based on its past performances), and increased levels of Bacillaceae at 28 days old were linked to higher race placings.

The team also investigated the long-term impact of foals receiving antibiotics during the first month of life. It was found that these foals had significantly lower fecal bacterial diversity at 28 days old than other foals who did not receive such treatments. Further analysis revealed that these foals won significantly lower prize money (an indicator of athletic performance) in their subsequent racing careers. In addition, foals who received antibiotics during their first 28 days of life had a significantly increased rate of developing a respiratory disease compared to their counterparts.

Interestingly, researchers also identified that low gut bacterial diversity in early life is associated with an increased risk of soft-tissue and orthopedic issues developing later in life. Researchers believe that the health impacts of low gut bacterial diversity in early life are likely to be related to immunological priming.

Work is currently underway to develop novel probiotics that will enhance the gut health of foals in early life and to investigate how antibiotics can be used while preserving gut health.

 Early-life gut bacterial community structure predicts disease risk and athletic performance in horses bred for racing, Scientific Reports (2024). DOI: 10.1038/s41598-024-64657-6

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:32am

Researchers show that pesticide contamination is more than apple-skin deep

Pesticides and herbicides are critical to ensuring food security worldwide, but these substances can present a safety risk to people who unwittingly ingest them. Protecting human health, therefore, demands sensitive analytical methods to identify even trace levels of potentially harmful substances. Now, researchers reporting in Nano Letters have developed a high-tech imaging method to detect pesticide contamination at low levels, and its application on fruits reveals that current food safety practices may be insufficient.

The analytical method called surface-enhanced Raman spectroscopy (SERS) is gaining popularity as a nondestructive method for detecting chemicals from modern farming on produce. With SERS, metal nanoparticles or nanosheets are used to amplify the signals created by molecules when they are exposed to a Raman laser beam. The patterns created by the metal-enhanced scattered light serve as molecular signatures and can be used to identify small amounts of specific compounds.

In tests of the silver-embedded membrane for food safety applications, the researchers sprayed the pesticides thiram and carbendazim, alone or together, onto apples, air-dried the fruits and then washed them to mimic everyday practices. When they laid their membrane over the apples, SERS detected pesticides on the apples, even though the chemicals were present at low concentrations. The team was also able to clearly resolve scattered-light signatures for each pesticide on apples sprayed with both thiram and carbendazim, as well as detect pesticide contamination through the fruit's peel and into the outermost layer of pulp.

But the pigmented skin of apple is very important.  A raw apple with skin contains up to 332% more vitamin K, 142% more vitamin A, 115% more vitamin C, 20% more calcium, and up to 19% more potassium than a peeled apple does.

The peel of 1 apple will contain about 8.4 mg of vitamin C and 98 IU of vitamin A. When eating apples, if you peel them off, the amount of this vitamin will decrease. down to 6.4 mg of Vitamin C and 61 IU of Vitamin A.

You can't remove them without severely effecting the nutrient quality of the fruits.

However, these results suggest that washing alone could be insufficient to prevent pesticide ingestion and that peeling would be required to remove potential contamination in the skin and outer pulp, the researchers say. Beyond apples, they also used the SERS membrane system to detect pesticides on cucumbers, shrimp, chili powder and rice.

But Cellulose Surface Nanoengineering for Visualizing Food Safety, Nano Letters (2024). DOI: 10.1021/acs.nanolett.4c01513 , pubs.acs.org/doi/abs/10.1021/acs.nanolett.4c01513

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:21am

Why your best friends' genes matter

"Choose your friends wisely, no scientifically". Because ....

A study by researchers shows that your best friend's traits can rub off on you—especially ones that are in their genes.

The genetic makeup of adolescent peers may have long-term consequences for individual risk of drug and alcohol use disorders, depression and anxiety, the groundbreaking study has found.

Peers' genetic predispositions for psychiatric and substance-use disorders are associated with an individual's own risk of developing the same disorders in young adulthood.

The data of this study exemplifies the long reach of social genetic effects.

Socio-genomics—the influence of one person's genotype on the observable traits of another—is an emerging field of genomics. Research suggests that peers' genetic makeup may influence health outcomes of their friends.

In the studies conducted, even when controlling for factors such as the target individuals' own genetic predispositions and family socioeconomic factors, the researchers found a clear association between peers' genetic predispositions and target individuals' likelihood of developing a substance use or psychiatric disorder. The effects were stronger among school-based peers than geographically defined peers.

Within school groups, the strongest effects were among upper secondary school classmates, particularly those in the same vocational or college-preparatory track between ages 16 and 19. Social genetic effects for school-based peers were greater for drug and alcohol use disorders than major depression and anxiety disorder.

More research is needed to understand why these connections exist. 

The most obvious explanation for why peers' genetic predispositions might be associated with our own well-being is the idea that our peers' genetic predispositions influence their phenotype, or the likelihood that peers are also affected by the disorder.

This research also underscores the importance of disrupting processes and risks that extend for at least a decade after attendance in school. Peer genetic influences have a very long reach.

Peer Social Genetic Effects and the Etiology of Substance Use Disorders, Major Depression, and Anxiety Disorder in a Swedish National Sample, American Journal of Psychiatry (2024). DOI: 10.1176/appi.ajp.20230358

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:09am

It's common knowledge that flying is not good for the climate. However, most people do not appreciate that contrails and jet fuel carbon emissions cause a double-whammy warming of the climate.
This study throws a spanner in the works for the aviation industry. Newer aircraft are flying higher and higher in the atmosphere to increase fuel efficiency and reduce carbon emissions. The unintended consequence of this is that these aircraft flying over the North Atlantic are now creating more, longer-lived, contrails, trapping additional heat in the atmosphere and increasing the climate impact of aviation.
This finding reflects the challenges the aviation industry faces when reducing its climate impact.
The study did confirm a simple step that can be taken to shorten the lifetime of contrails: Reduce the amount of soot emitted from aircraft engines, produced when fuel burns inefficiently.

Modern aircraft engines are designed to be cleaner and typically emit fewer soot particles, which cuts down the lifetime of contrails.

While other studies using models have predicted this phenomenon, the study published today is the first to confirm it using real-world observations.
Even higher in the sky, the researchers found that private jets create contrails more often than previously thought—adding to concerns about the excessive use of these aircraft by the super-rich.

Despite being smaller and using less fuel, private jets create similar contrails to much larger commercial aircraft, the analysis found.
Private jets fly higher than other planes, more than 40,000 feet above earth where there is less air traffic. However, like modern commercial aircraft creating more contrails compared to lower-flying older commercial aircraft, the high altitudes flown by private jets means they create outsized contrails.

 Operational differences lead to longer lifetimes of satellite detectable contrails from more fuel efficient aircraft, Environmental Research Letters (2024). DOI: 10.1088/1748-9326/ad5b78

Part 2

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:04am

Modern aircraft emit less carbon than older aircraft, but their contrails may do more environmental harm

Modern commercial aircraft flying at high altitudes create longer-lived planet-warming contrails than older aircraft, a new study has found.

The result means that although modern planes emit less carbon than older aircraft, they may be contributing more to climate change through contrails.

The study highlights the immense challenges the aviation industry faces to reduce its impact on the climate. The new study also found that private jets produce more contrails than previously thought, potentially leading to outsized impacts on climate warming.

Contrails, or condensation trails, are thin streaks of cloud created by aircraft exhaust fumes that contribute to global warming by trapping heat in the atmosphere.

While the exact warming effect of contrails is uncertain, scientists think it is greater than warming caused by carbon emissions from jet fuel.
Published in Environmental Research Letters, the study used machine learning to analyze satellite data on more than 64,000 contrails from a range of aircraft flying over the North Atlantic Ocean.

Modern aircraft that fly at above 38,000 feet (about 12km), such as the Airbus A350 and Boeing 787 Airliners, create more contrails than older passenger-carrying commercial aircraft, the study found.

To reduce jet fuel consumption, modern aircraft are designed to fly at higher altitudes where the air is thinner with less aerodynamic drag, compared to older commercial aircraft, which usually fly at slightly lower altitudes (around 35,000ft/11km).

This means these higher-flying aircraft create less carbon emissions per passenger. However, it also means they create contrails that take longer to dissipate—creating a warming effect for longer and a complicated trade-off for the aviation industry.

Part 1

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 8:47am

The raccoon dog's significantly smaller brain size supports this hypothesis, highlighting that factors other than domestication, such as ecological adaptations like hibernation, can also drive reductions in brain size.

The study concludes that while domestication does contribute to brain size reduction in dogs, it should not be overemphasized as a uniquely powerful evolutionary force.

The findings suggest that other ecological and evolutionary pressures can similarly affect brain size and can mediate extreme variations in non-domesticated species as well. A more balanced and less human-focused perspective could refine our understanding of the complex interplay between domestication and brain size evolution in mammals.

 László Zsolt Garamszegi et al, The reduction in relative brain size in the domesticated dog is not an evolutionary singularity among the canids, Biology Letters (2024). DOI: 10.1098/rsbl.2024.0336 , royalsocietypublishing.org/doi … .1098/rsbl.2024.0336

Part 2

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 8:46am

Domestication causes smaller brain size in dogs than in the wolf: Study challenges notion

A recent study, published in Biology Letters, challenges the long-held notion that domestication is the primary driver of reduced brain size in domesticated animals, specifically dogs.

Employing a phylogenetic comparative approach, researchers  show that the domesticated dog does not exhibit an exceptionally small brain relative to its body size compared to other canid species, suggesting that  domestication is not as unique an evolutionary force as previously thought.

The prevailing belief has been that domestication leads to a significant reduction in brain size due to relaxed selection pressures, such as reduced need for foraging, mating competition, and predator avoidance.

This phenomenon is thought to be a result of the decreased necessity for metabolically costly brain tissue in a domesticated environment. While domesticated dogs show a substantial decrease in brain size compared to their wild ancestor, the gray wolf (Canis lupus), this study aimed to determine if this reduction is exceptional when viewed in a broader phylogenetic context.

Researchers analyzed brain and body size data for 25 canid species, including ancient dog breeds that are genetically closer to the ancestral domesticated dog.

Their phylogenetic predictions and allometric regressions showed that the reduction in brain size in domesticated dogs is not an unambiguous evolutionary singularity. The observed brain size in dogs fell within the expected range for most ancient breeds used in the study, suggesting that domestication is not uniquely influential in reducing brain size among canids.

Interestingly, the study found that the common raccoon dog (Nyctereutes procyonoides), which hibernates, is a more pronounced outlier in terms of brain size reduction. Hibernation, associated with prolonged periods of low metabolic activity and food scarcity, is hypothesized to constrain brain size evolution due to the high energy demands of large brains.

Part 1

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