Comment

Comment by Dr. Krishna Kumari Challa on August 29, 2021 at 12:36pm

So insect ecologists Jessica Kansman and Sara Hermann are looking into ways of tweaking the use of pest species' natural enemies to make it more practical. They presented results of their progress at this week's meeting of the American Chemical Society.

In a series of trials the researchers let collard-snacking aphids (Myzus persicae) choose between the scent of leaves with predatory ladybugs (Harmonia axyridis) on them or the smell of leaves with no ladybug.

They found exposure to the ladybug scent impacted the aphids' plant choices and even reduced their reproductive rate.

"Our early work has shown that these fear-based responses can change insect behaviors in ways that reduce their damage on these crop plants.

Preliminary field tests using three methoxypyrazine compounds (which we humans would recognize as the smell of ladybugs) isolated from ladybug stink have produced promising results - with aphids avoiding the sprayed collard crops as if ladybugs were present.

"The beauty of these compounds being specific to these insects is that it's an honest cue. The use of natural enemy odor cues is a promising future direction for applied chemical ecology in sustainable pest management

https://scitechdaily.com/using-the-smell-of-fear-to-protect-gardens...

https://www.sciencealert.com/researchers-propose-harnessing-the-ste...

part2

Comment by Dr. Krishna Kumari Challa on August 29, 2021 at 12:33pm

We Can Make Powerful Nature-Inspired 'Pesticides' Without Poison, Scientists Say

While no one enjoys seeing carefully nurtured crops destroyed by hordes of hungry insects, the most common way to prevent it – the use of insecticides – is causing massive ecological problems.

Some are wreaking havoc on bee populations globally, killing birds and piling onto the challenges already faced by endangered species. Thankfully, insecticides are generally only in our food at low levels, but they do harm humans who are highly exposed to them too, like the workers growing our crops. 

They also destroy predatory insect populations, which just makes the problem of crop pests worse in the long term - with fewer pest enemies around to keep their numbers in check.

One alternative that researchers and farmers have been putting to the test is the use of predatory insects to control the problematic plant eaters. However, this approach, known as biological control, has its own challenges.

While insecticides can target multiple pest species, this is a lot harder to achieve when relying on natural predators. Releasing multiple predators could just lead to them preying on each other, or competing with each other for the same pest, as predators may not always target their intended species.

The predators are also very reliant on environmental conditions – temperature and day length can alter their behavior so they may only be effective during certain seasons. This, along with the fact that some pests are invasive and have no native predators means some pesticides may still need to be used, which can then also impact the predators.

part 1

Comment by Dr. Krishna Kumari Challa on August 29, 2021 at 11:20am

If You See Square Waves, Get Out of the Water!

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 9:33am

One IC element assesses with moderate confidence that the first human infection with SARS-CoV-2 most likely was the result of a laboratory-associated incident, probably involving experimentation, animal handling, or sampling by the Wuhan Institute of Virology. These analysts give weight to the inherently risky nature of work on coronaviruses, it said.

Analysts at three IC elements remain unable to coalesce around either explanation without additional information, with some analysts favouring natural origin, others a laboratory origin, and some seeing the hypotheses as equally likely. Variations in analytic views largely stem from differences in how agencies weigh intelligence reporting and scientific publications, and intelligence and scientific gaps, the report said.

Press Trust of India

https://www.business-standard.com/article/current-affairs/covid-19-...

https://www.dni.gov/index.php/newsroom/reports-publications/reports...

https://www.nature.com/articles/d41586-021-02366-0

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 9:31am

Covid-19 not developed as biological weapon: US intelligence community

SARS-CoV-2, the virus that causes Covid-19, was 'not developed' as a biological weapon, the US intelligence community has concluded in a report

SARS-CoV-2, the virus that causes COVID-19, was "not developed" as a biological weapon, the US intelligence community has concluded in a report.

The Director of National Intelligence in a report, prepared at the direction of the president, on Friday said SARS-CoV-2 probably emerged and infected humans through an initial small-scale exposure that occurred no later than November 2019 with the first known cluster of COVID-19 cases arising in Wuhan, China in December 2019.

However, there was no unanimity among the intelligence community (IC) on the origins of the coronavirus.

The virus was not developed as a biological weapon. Most agencies also assess with low confidence that SARS-CoV-2 probably was not genetically engineered; however, two agencies believe there was not sufficient evidence to make an assessment either way, said the unclassified version of the report.

The IC also assesses that China's officials did not have foreknowledge of the virus before the initial outbreak of COVID-19 emerged, it said.

After examining all available intelligence reporting and other information, though, the IC remains divided on the most likely origin of COVID-19. All agencies assess that two hypotheses are plausible: natural exposure to an infected animal and a laboratory-associated incident, the report said.

Four IC elements and the National Intelligence Council assess with low confidence that the initial SARS-CoV-2 infection was most likely caused by natural exposure to an animal infected with it or a close progenitor virus-a virus that probably would be more than 99 per cent similar to SARS-CoV-2.

These analysts give weight to Chinese officials' lack of foreknowledge, the numerous vectors for natural exposure, and other factors, the report said.

part 1

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 9:13am

Mutation rate of COVID-19 virus is at least 50 percent higher than previously thought

The virus that causes COVID-19 mutates almost once a week—significantly higher than the rate estimated previously—according to a new study by scientists . Their findings indicate that new variants could emerge more quickly than thought previously.

SARS-CoV-2, the virus that causes COVID-19, was previously thought to mutate about once every two weeks. However, new research shows that this estimate overlooked many mutations that happened but were never sequenced.

Viruses regularly mutate, for example when mistakes are made in copying the genomes whilst the virus replicates.

Usually when we consider natural selection, we think about new mutations that have an advantage and so spread, such as the Alpha and Delta variants of COVID-19. This is known as Darwinian selection or positive selection.

However, most mutations are harmful to the virus and reduce its chances of surviving—this is called purifying or negative selection. These negative mutations don't survive in the patient long enough to be sequenced and so are missing from calculations of the mutation rate.

Allowing for these missing mutations, the team estimates that the true mutation rate of the virus is at least 50% higher than previously thought.

The findings, published in Genome Biology and Evolution, reinforce the need to isolate individuals with immune systems that struggle to contain the virus.  These findings mean that if a patient suffers COVID-19 for more than a few weeks, the virus could evolve which could potentially lead to new variants.

The Alpha variant is thought to be the result of evolution of the virus within an individual who was unable to clear the infection.

It's not all bad news because most individuals transmit and clear the virus before it mutates all that much, meaning that the chance of evolution within one patient isn't usually that high. However, this new estimate of the mutation rate indicates that there is more scope for evolution of the virus within such individuals than scientists assumed.

 Atahualpa Castillo Morales et al, Causes and consequences of purifying selection on SARS-CoV-2, Genome Biology and Evolution (2021). DOI: 10.1093/gbe/evab196

https://phys.org/news/2021-08-mutation-covid-virus-percent-higher.h...

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 8:55am

This enormous study, using data on over 29 million vaccinated people, has shown that there is a very small risk of clotting and other blood disorders following first dose COVID-19 vaccination. Though serious, the risk of these same outcomes is much higher following SARS-CoV-2 infection.

Julia Hippisley-Cox et al, Risk of thrombocytopenia and thromboembolism after covid-19 vaccination and SARS-CoV-2 positive testing: self-controlled case series study, BMJ (2021). DOI: 10.1136/bmj.n1931

https://medicalxpress.com/news/2021-08-covid-vaccination-biggest-bl...

part3

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 8:54am

Researchers from the University of Oxford have recently announced the results of a study into thrombocytopenia (a condition with low platelet counts) and thromboembolic events (blood clots) following vaccination for COVID-19, some of the same events which have led to restricted use of the Oxford-AstraZeneca vaccine in a number of countries.

Writing in the British Medical Journal (BMJ), they detail the findings from over 29 million people vaccinated with first doses of either the ChAdOx1 nCov-19 "Oxford-AstraZeneca" vaccine or the BNT162b2 mRNA "Pfizer-BioNTech' vaccine. They conclude that with both of these vaccines, for short time intervals following the first dose, there are increased risks of some hematological and vascular adverse events leading to hospitalization or death.

However, people should be aware of these increased risks after COVID-19 vaccination and seek medical attention promptly if they develop symptoms, but also be aware that the risks are considerably higher and over longer periods of time if they become infected with SARS-CoV-2.

The authors further note that the risk of these adverse events is substantially higher and for a longer period of time, following infection from the SARS-CoV-2 "coronavirus" than after either vaccine.

All of the coronavirus vaccines currently in use have been tested in randomized clinical trials, which are unlikely to be large enough to detect very rare adverse events. When rare events are uncovered, then regulators perform a risk-benefit analysis of the medicine; to compare the risks of the adverse events if vaccinated versus the benefits of avoidance of the disease—in this case, COVID-19.

part 2

Comment by Dr. Krishna Kumari Challa on August 28, 2021 at 8:48am

COVID-19, not vaccination, presents biggest blood clot risks: study

Part 1

Comment by Dr. Krishna Kumari Challa on August 27, 2021 at 1:46pm

Breaking Bad Chemicals With Bacterial Detoxifiers

India’s landfills are home to tiny environmental detoxifiers—bacteria that transform chemical wastes into harmless substances.

While bacteria get a bad rap as disease-causing agents, some of these tiny organisms may just be the rescuers of the environment. An international team found that bacteria from Indian landfills could detoxify chemical wastes called hexabromocyclodecane (HBCD), publishing their study in Chemosphere.

For a long time, industrial production has been a major culprit of environmental pollution, releasing hazardous waste like HBCD. At peak production, HBCD hit scales of 10,000 tons a year as a flame retardant used in textile manufacturing and integrated in plastics for electronic devices.

By the time the chemical was banned worldwide in 2014, the damage had been done. As a long-lived environmental toxin, HBCD had already seeped into sewages, soil and the air—found even in the food chain and consequently, in human blood samples and breast milk.

Given HBCD’s persistence in the surroundings, researchers have been searching for ways to detoxify the chemical pollution from the past to create a cleaner future. Scientists from the University of Delhi and the India Habitat Center, together with collaborators from Sweden, found a solution from nature itself—showing that Sphingobium indicum bacteria inhabiting India’s landfills could digest these chemicals.

The detoxifying abilities of these bacteria come from an enzyme called LinA, which is involved in metabolizing another now-banned insecticide and chemical sibling of HBCD. Known as biological catalysts, enzymes speed up reactions like the breakdown of chemicals.

On the designated binding site, the toxin attaches itself to LinA, similar to a key being inserted into a lock. HBCD rapidly splits up into non-toxic fragments, which are then released to make room for the next chemical to latch onto the enzyme’s binding site.

By genetically modifying the bacteria, the team also altered the structure of the enzymes they produced. While LinA enzymes are highly selective about the molecules they can accept on the binding site, the genetic changes led to a more spacious site for accommodating larger chemicals.

According to the researchers, these experiments highlight the possibility of designing enzymes that can degrade other toxins besides HBCD. Through modifying biological structures, biotransformation may be key to engineering useful bacterial enzymes for remediating heavily polluted environments.

 Heeb et al. (2021) Transformation of ε-HBCD with the Sphingobium indicum Enzymes LinA1, LinA2 and LinATM, a Triple Mutant of LinA2.

https://www.asianscientist.com/2021/08/in-the-lab/bacteria-chemical...

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