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Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 3:31pm

Cosmic Cycles: Earth, Our Home

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 3:27pm

Human DNA is everywhere. That's a boon for science, and an ethical quagmire

In the water, on the land, in the air. In most cases the quality of DNA is almost equivalent to if you took a sample from a person.

We  cough, spit, shed and flush our DNA into all of these places and countless more. Signs of human life can be found nearly everywhere, short of isolated islands and remote mountaintops, according to a new  study.

That ubiquity is both a scientific boon and an ethical dilemma, say the UF researchers who sequenced this widespread DNA. The DNA was of such high quality that the scientists could identify mutations associated with disease and determine the genetic ancestry of nearby populations. They could even match genetic information to individual participants who had volunteered to have their errant DNA recovered.

Ethically handled environmental DNA samples could benefit fields from medicine and environmental science to archaeology and criminal forensics. For example, researchers could track cancer mutations from wastewater or spot undiscovered archaeological sites by checking for hidden human DNA. Or detectives could identify suspects from the DNA floating in the air of a crime scene.

But this level of personal information must be handled extremely carefully. Now, scientists and regulators must grapple with the ethical dilemmas inherent in accidentally—or intentionally—sweeping up human genetic information, not from blood samples but from a scoop of sand, a vial of water or a person's breath.

Published May 15 in Nature Ecology and Evolution, a paper by researchers outlines the relative ease of collecting human DNA nearly everywhere they looked.

Because of the ability to potentially identify individuals, the researchers say that ethical guardrails are necessary for this kind of research. The study was conducted with approval from the institutional review board of UF, which ensures that ethical guidelines are adhered to during research studies.

1. Liam Whitmore, Mark McCauley, Jessica A. Farrell, Maximilian R. Stammnitz, Samantha A. Koda, Narges Mashkour, Victoria Summers, Todd Osborne, Jenny Whilde, David J. Duffy. Inadvertent human genomic bycatch and intentional capture raise beneficial applications and ethical concerns with environmental DNA. Nature Ecology & Evolution, 2023; DOI: 10.1038/s41559-023-02056-2

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Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 7:15am

WHO warns against artificial sweeteners

Sweeteners don’t help people to lose weight in the long run and could increase the risk of type 2 diabetes and cardiovascular diseases if consumed continuously, the World Health Organization (WHO) advises. The guideline includes both artificial and natural sweeteners, such as aspartame and stevia. But it’s conditional, in keeping with life’s complexities — the WHO isn’t warning against sweetened toothpaste, for example, or recommending a change for people with pre-existing diabetes. The announcement contradicts some findings that sweeteners are harmless, even if they don’t offer any health benefits.

https://www.who.int/publications/i/item/9789240073616?utm_source=Na...

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 7:13am

CRISPR zeroes in on death cap antidote

The CRISPR–Cas9 gene-editing tool might have cracked the mystery of how death cap mushrooms (Amanita phalloides) kill — and it led researchers to a potential antidote. Using the gene-editing technology, researchers created a pool of human cells — each with different genetic mutations — and exposed them to the mushrooms’ toxin. The toxin could not enter cells that lacked a functional version of an enzyme called STT3B, and cell survival increased. The researchers then sifted through thousands of chemical compounds to find one that would block the action of STT3B. They uncovered indocyanine green, a dye developed by the photography company Kodak in the 1950s and used in medical imaging. Indocyanine green has not yet been tested as an antidote in humans, but it reduced deaths when given to mice.

https://www.nature.com/articles/s41467-023-37714-3.epdf?sharing_tok...

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 7:11am

Our Earth is becoming unlivable. Can we still turn the tide?

We have crossed six of the nine boundaries within which human life on Earth will still be possible for future generations. That is not good news. Can the tide still be turned?

The planetary boundaries were discussed on May 9 as part of the Leiden University Green Office's Sustainability Day. They include climate change, biodiversity loss and ocean acidification. Six of the nine boundaries have already been crossed (see figure above). Crossing planetary boundaries increases the risk of large-scale abrupt or irreversible environmental changes.

Drastic changes are needed to ensure that the Earth remains habitable. Systemic changes are needed in food, energy and how we live and consume. In fact, all planetary boundaries are interconnected.

For example, once the nitrogen limit is exceeded, it affects biodiversity and climate. Besides planetary boundaries, experts also stress the importance of social boundaries, which include education, social equality and health care. Planetary boundaries and social  boundaries affect each other, and if we are to preserve a livable Earth, they must be addressed in an integrated way—which is possible.

One approach that can help keep the Earth livable is to let communities come up with their own local solutions. You see that communities often achieve more than their original goal. There is hope if we give communities responsibility for themselves.

source: https://www.universiteitleiden.nl/en

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 6:47am

Heat wave in Asia made 30 times more likely because of climate change, scientists say

A searing heat wave in parts of southern Asia in April this year was made at least 30 times more likely by climate change, according to a rapid study by international scientists released recently.

Sizzling temperatures of up to 45 degrees Celsius (113 degrees Fahrenheit) were recorded in monitoring stations in parts of India, Bangladesh, Thailand and Laos last month—which was unusually high for the time of year.

The climate-change-fueled heat caused deaths, widespread hospitalizations, damaged roads, sparked fires and led to school closures in the region.

The World Weather Attribution group uses established models to quickly determine whether climate change played a part in extreme weather events. While the studies themselves are not yet peer-reviewed, which is the gold standard for science, they are often later published in peer-reviewed journals.

The southern Asian region is considered among the most vulnerable to climate change in the world, according to various global climate studies. But India, the largest country in the region and the most populous in the world is also currently the third highest emitter of planet-warming gases.

Scientists say that drastic measures to reduce carbon dioxide emissions immediately is the only solution.

Heat waves will become more common, temperatures will rise even more and the number of hot days will increase and become more frequent if we continue to pump greenhouse gases into the atmosphere, according to them.

www.worldweatherattribution.or … e-event-attribution/

Source: AP

https://phys.org/news/2023-05-asia-climate-scientists.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 6:34am

The team tested various samples of silicone, including some they synthesized themselves as well as commercial-grade medical tubing used for urinary catheters. They then subjected these samples to mechanical forces to create surface damage. Their experiments showed that the microcracks can be formed very easily.

Even  wiping with lab tissue was enough to create surface damage. To the unaided  eye it still looks fine, but under the microscope, scientists could already see microcracks of the size that bacteria could get into. Bacteria are only a few micrometers big, so it doesn't take much. They saw that the bacteria very clearly preferred to attach in these microscopic cracks.

In the bent samples, there were four to five times as many bacteria on the side that was in tension versus the side that was in compression. These cells have full choice about where to grow, but they clearly love the side where all these microcracks are opened up.

Now scientists are researching methods to reduce surface damage, or modifying the silicone surface to reduce the formation of such cracks.

Desmond van den Berg et al, Mechanical deformation of elastomer medical devices can enable microbial surface colonization, Scientific Reports (2023). DOI: 10.1038/s41598-023-34217-5

Part 2

Comment by Dr. Krishna Kumari Challa on May 18, 2023 at 6:30am

How bending implantable medical devices can lead to bacterial growth

A study by researchers  shows that mechanical deformation of medically implantable materials—such as bending or twisting—can have a big impact on the formation of potentially harmful biofilms.

The study, described in a paper published in Scientific Reports, shows that even slight bending of elastomeric materials such as polydimethylsiloxane (PDMS)—also known as silicone—opens up microscopic cracks that are perfect environments for colonizing bacteria.

These kinds of materials are used in all kinds of biomedical applications, from catheters to tracheal tubes and prosthetic breast implants.

The formation of microbial biofilms on these materials is common, but scientists were surprised by the degree to which bending silicone, and other rubber materials, causes these cracks to reversibly open and close—and how big a difference they make in terms of biofilm formation.

Biofilms are complex communities of organisms that grow on surfaces. While individual microbial cells are susceptible both to antibiotics and the body's natural defensive systems, the biofilm environment can shield them from these interventions, which can lead to persistent infections.

Infections associated with medical-device biofilms, which sometimes develop after surgery, can be serious health risks—lengthening hospital stays or causing patients who have been discharged to be readmitted.

They have combined not only   microbiology and materials science, but also mechanical engineering, because they're talking about mechanical stress, strain and deformation. This bending effect is something that had not been noticed before.

Part 1

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 11:36am

Why wavy wounds heal faster than straight wounds

Wavy wounds heal faster than straight wounds because shapes influence cell movements, a team of researchers has found.

Scientists observed the motion of cells and found that those near wavy shaped wounds moved in a swirling manner while cells near straight wounds moved in straight lines, traveling parallel to the edges.

The team concluded that the swirling or vortex-like movement is crucial to gap bridging, in which cells build bridges to heal damaged tissues, and which accelerates the wound healing process in wavy wounds.

This is the first time that the relationship between gap bridging, and the speed of wound healing has been determined. The scientists said their findings open the door to the development of more effective strategies to speed up wound healing, for better wound management, tissue repair, and plastic surgery.

An essential component of wound healing is re-epithelialization, a process in which the epithelial cell—a type of cell found on the skin—moves to form a bridge between the wound and the skin, closing its gap.

While previous studies have found that zig zag wounds healed faster than straight wounds, little is known about how different wound curvatures (shape) and wound sizes influence healing efficiency, nor about the mechanism of re-epithelialization.

To investigate, the NTU scientists prepared synthetic wounds with a range of widths (30 micrometers to 100 micrometers) and curvatures (radius of curvature: 30 micrometers, 75 micrometers, 150 micrometers and straight line) to learn how cells moved to close wound gaps in different circumstances.

Using particle image velocimetry—an optical measurement technique for fluid flow—researchers found that wavy wounds induced more complex collective cell movements, such as a swirly, vortex-like motion. By contrast in a straight wound, cells moved parallel to the wound front, moving in straight lines like a marching band.

Wavy wounds heal nearly five times faster

The  team also observed the healing progress of the synthetic wounds over a period of 64 hours and found that the healing efficiency of wavy gaps—measured by the percentage area covered by the cells over time—is nearly five times faster than straight gaps.

 Hongmei Xu et al, Geometry-mediated bridging drives nonadhesive stripe wound healing, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2221040120

Comment by Dr. Krishna Kumari Challa on May 17, 2023 at 9:50am

How superbug A. baumannii survives metal stress and resists antibiotics

The deadly hospital pathogen Acinetobacter baumannii can live for a year on a hospital wall without food and water. Then, when it infects a vulnerable patient, it resists antibiotics as well as the body's built-in infection-fighting response. The World Health Organization (WHO) recognizes it as one of the three top pathogens in critical need of new antibiotic therapies.

Now a team of international researchers have discovered how the superbug can survive harsh environments and then rebound, causing deadly infections. They have found a single protein that acts as a master regulator. When the protein is damaged, the bug loses its superpowers allowing it to be controlled, in a lab setting. The research is published in Nucleic Acids Research.

During infection our cells fight back by either flooding or starving bacteria of essential metals such as copper and zinc. A. baumannii has strong drug pumps that push antibiotics, metals and other threats out of the cell.

By studying how this bug deals with infection stresses,  researchers have found an important uncharacterized regulatory protein (DksA). When scientists disrupted this protein, it lead to changes in about 20 percent of the bug's genome and breaks its pumping system.

Ram P Maharjan et al, DksA is a conserved master regulator of stress response in Acinetobacter baumannii, Nucleic Acids Research (2023). DOI: 10.1093/nar/gkad341

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