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Comment by Dr. Krishna Kumari Challa on August 26, 2021 at 10:04am

Why the changing colour of our streetlights could be a danger for insect populations

Life on Earth has evolved alongside predictable cycles of day and night. But this pattern has become increasingly blurred. Between 2012 and 2016, satellite measurements revealed that the global area polluted by artificial light grew by 2% each year, intruding ever deeper into biodiversity hotspots like tropical forests.

In this context, there is an important change taking place in the world: the replacement of older, less energy-efficient sodium street-lighting with white LEDs.

LEDs used in streetlights typically emit white light, while sodium lamps have a characteristic yellow glow – as seen in the picture below. This change in the colour of artificial light is predicted to have major consequences for wildlife. That’s because white LEDs emit light across the entire visible spectrum. The more wavelengths emitted, the greater the diversity of species and biological processes that are likely to be disrupted.

Insects are known to be more sensitive to shorter, bluer wavelengths of light, which are largely absent from sodium lighting. Biological processes that are controlled by daylight and internal circadian rhythms, such as reproduction, are more likely to be disrupted or prevented by white LEDS.

A study results published in Science Advances recently were striking. Lighting reduced the numbers of caterpillars by between one half and one third. Lit areas almost universally had lower numbers than their darker counterparts. Sites with white LEDs also had a steeper reduction in numbers compared to sites with sodium lamps.

We suspect the reason there were fewer caterpillars in lit areas was because the lighting prevented females from laying eggs, a behaviour that has evolved in darkness. In addition, adult moths can be drawn up to streetlights, where they’re easy pickings for bats. Our recent review article revealed many other plausible mechanisms through which lighting could cause population declines throughout the moths’ life cycles.

https://advances.sciencemag.org/content/7/35/eabi8322

https://theconversation.com/why-the-changing-colour-of-our-streetli...

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 1:52pm

In the last 50 years, we've seen increasing levels of new pathogens spreading through humans. SARS-CoV-2 is the most obvious example, but even in the last few decades we've had swine flu, bird flu, Ebola, and many, many more.

"Together with recent estimates of increasing rates of disease emergence from animal reservoirs associated with environmental change," the team writes, "this finding suggests a high probability of observing pandemics similar to COVID-19 (probability of experiencing it in one's lifetime currently about 38 percent), which may double in coming decades.

So, even while we are recovering from a current outbreak, it's important that we don't assume we won't see another life-changing pandemic soon enough.

In fact, if we play our cards right, our response and resources for COVID-19 can prepare us for the next pandemic.

https://www.pnas.org/content/118/35/e2105482118

part 2

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 1:51pm

The Probability of Another COVID-Level Pandemic Emerging is higher than you think

a new statistical study has discovered that large pandemics are much more common than you might expect. In fact, the team found that a pandemic with a similar level of impact to COVID-19 has around a 2 percent probability of occurring each year.

When you add that up across an entire lifetime, this means we each have a 38 percent chance of experiencing a big one at least once, and the odds look set to get worse with time.

The most important takeaway is that large pandemics like COVID-19 and the Spanish flu are relatively likely.

The team looked at the historical record of epidemics from the year 1600 until now. They found 476 documented epidemics, around half of which had a known number of casualties. About 145 caused less than 10,000 deaths, while 114 others we know existed, but not the number of deaths.

Importantly, infectious diseases that are currently active were excluded from the analysis – so that means no COVID-19, HIV, or malaria.

The team used detailed modelling with a generalized Pareto distribution to analyze the data, finding that the yearly number of epidemics is immensely variable, and an extreme epidemic like the Spanish flu of 1918-1920 had a probability of occurring somewhere between 0.3 and 1.9 percent each year over the last 400 years.

"The slow decay of probability with epidemic intensity implies that extreme epidemics are relatively likely, a property previously undetected due to short observational records and stationary analysis methods

part 1

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 1:09pm

Can DNA be washed away?

In forensic casework, DNA of suspects could be found frequently on clothes of drowned bodies after hours, sometimes days of exposure to water. ... All in all, the results demonstrate that DNA could still be recovered from clothes exposed to water for more than 1 week.3

https://pubmed.ncbi.nlm.nih.gov/28963636/

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 1:06pm

What factors can affect DNA evidence?

Several factors can affect the DNA left at a crime scene, such as environmental factors (e.g., heat, sunlight, moisture, bacteria, and mold). Therefore, not all DNA evidence will result in a usable DNA profile. Further, DNA testing cannot identify when the suspect was at the crime scene or for how long.

--

Murderers desperate to get rid of evidence might want to consider using bleach to wash away stains. But not just any bleach will do. When old-school chlorine-based bleach is splashed all over blood-stained clothing, even if the clothes are washed ten times, DNA is still detected.

So for the criminal aspiring for perfection, here’s the secret you’ll need to know: It’s the oxygen-producing detergents that will get rid of any incriminating evidence for good.

Researchers at the University of Valencia tested oxygen bleach on blood-stained clothing for two hours and found that it destroys all DNA evidence. Forensic tests such as luminal tests rely on the ability of blood to uptake oxygen: A protein in the blood called hemoglobin (responsible for transporting oxygen throughout the body) reacts with hydrogen peroxide and gives a positive test result.

Chlorine-based detergents contaminate blood, but leave behind intact hemoglobin. However, detergents such as Reckitt Benckiser’s Vanish produce oxygen bubbles, which cause the blood to degrade and no longer uptake oxygen.

Hopefully, anyone actually contemplating cleaning up bloodstains isn’t reading this.

https://www.discovermagazine.com/the-sciences/want-to-get-away-with...

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 12:45pm

How the same plant species can program itself to flower at differen...

Researchers led by Professor Caroline Dean have uncovered the genetic basis for variations in the vernalization response shown by plants growing in very different climates, linking epigenetic mechanisms with evolutionary change.

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 12:42pm

Is There Plastic in your Rain? Yes!

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 12:28pm

High cholesterol fuels cancer by fostering resistance to a form of cell death

Chronically high cholesterol levels are known to be associated with increased risks of breast cancer and worse outcomes in most cancers, but the link has not been fully understood.

In a new study  appearing online Aug. 24 in the journal Nature Communications, a research team led by the Duke Cancer Institute has identified the mechanisms at work, describing how breast cancer cells use cholesterol to develop tolerance to stress, making them impervious to death as they migrate from the original tumor site.

Most cancer cells die as they try to metastasize—it's a very stressful process. The few that don't die have this ability to overcome the cell's stress-induced death mechanism. researchers now  found that cholesterol was integral in fueling this ability.

In the current study using cancer cell lines and mouse models, the  researchers found that migrating cancer cells gobble cholesterol in response to stress. Most die.

But in the what-doesn't-kill-you-makes-you-stronger motif, those that live emerge with a super-power that makes them able to withstand ferroptosis, a natural process in which cells succumb to stress. These stress-impervious cancer cells then proliferate and readily metastasize.

The process appears to be used not only by ER-negative breast cancer cells, but other types of tumors, including melanoma. And the mechanisms identified could be targeted by therapies.

https://www.nature.com/articles/s41467-021-25354-4

Dysregulated cholesterol homeostasis results in resistance to 2 ferroptosis and increased cancer cell metastasis, Nature Communications (2021).

https://medicalxpress.com/news/2021-08-high-cholesterol-fuels-cance...

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 10:53am

In addition to the genes that are tightly bundled up into chromosomes, bacteria and certain other microbes have other shorter, circular strands of DNA, called plasmids. Not only can plasmids replicate, they also have much fewer genes than their chromosomal counterparts. These properties make plasmids easier to manipulate with genetic tools. In particular, segments of DNA from other organisms, known as transgenes, can be inserted into bacterial plasmids.

Further, as plasmids replicate, multiple copies of the transgenes are produced. For example, if the human gene for making insulin is inserted into a plasmid, then as the bacteria replicate, more copies of the plasmids and consequently insulin genes are made. And so, when these genes are expressed, more insulin is produced. Alternately, plasmids can be extracted from the bacteria and used as vehicles to insert transgenes into the genome of other cells to alter traits in those cells.

The researchers noted that while these types of genetic manipulations have been routine in mammalian cells and other simple microbes, they have often been difficult to orchestrate in more complex, multicellular organisms. To overcome these hurdles, Sun and her team selected a bacteria-host pair that have a symbiotic relationship. In particular, they chose the soil-dwelling worm, C. elegans, that feeds on E. coli.

First, they inserted a transgene into E. coli's plasmid that can interfere with a genetically engineered strain of C. elegans, which has the ability to glow fluorescently green. Then, using a chemical, they induced the plasmid to express the green fluorescence-suppressing gene. Last, they fed the bacteria to C. elegans and found that only those C. elegans that consumed the E. coli with the transgene stopped glowing green.

In addition, Sun and her team programmed E. Coli to produce gene products with different "AND" and "OR" logic gates. Put simply, gene products could be selectively produced only by the combined action of two or more genes, like the mathematical "AND" operation, or if any one gene was expressed, like the mathematical "OR" operation. Once again, using chemical triggers, the researchers initiated an "AND" or "OR" combination of gene expression in the E. Coli needed to silence twitching behavior in C. elegans after the worms fed on the bacteria.

Sun said that their bacteria-based gene silencing system could be easily extended to other living systems for applications in pest control, plant growth promotion and veterinary disease diagnosis.

"Bacteria have a symbiotic relationship with many species, affecting their hosts' metabolism, immunity and behavior," said Sun. "Here, we have taken advantage of the symbiosis between bacteria and a relatively complex organism to engineer a programmable genetic tool that can influence host physiology in a positive way."

https://phys.org/news/2021-08-genetically-good-bacteria-aid-combati...

part 2

Comment by Dr. Krishna Kumari Challa on August 25, 2021 at 10:52am

Microbiome-based therapies: Genetically engineered good bacteria could aid in combating disease

Our bodies are home to several bacterial species that help us maintain our health and wellbeing. Thus, engineering these good bacteria to alter the activity of genes gone awry, either by turning them down or by activating them, is a promising approach to improve health and combat diseases.

n a study published in the journal Nature Communications, researchers at Texas A&M University have developed a sophisticated, programmable gene silencing system that might have future therapeutic implications.

Using chemical triggers, the researchers showed that lab-engineered bacteria Escherichia coli (E. coli) could be induced to make gene products to suppress certain traits in Caenorhabditis elegans (C. elegans), a roundworm that consumes this strain of bacteria as food. Similarly, the researchers noted that in the future, symbiotic bacteria within the human microbiome could be engineered to sense, record and deliver therapeutics to improve health and wellbeing.

Here, researchers have used bacteria to tweak the gene expression in another organism, which is a proof of concept that bacteria living in symbiosis with humans could be engineered to modulate human physiology and treat disease.

Baizhen Gao et al, Programming gene expression in multicellular organisms for physiology modulation through engineered bacteria, Nature Communications (2021). DOI: 10.1038/s41467-021-22894-7

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