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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.

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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

Part 1

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

A host  enzyme allows viruses to ride roughshod in the liver, paving the way to cancer

Chronic viral infections in the liver can lead to organ dysfunction and ultimately to liver tumors in a progression invariably characterized by viruses that proliferate free of immune system restraints.

Although it has been known for decades that chronic viral infection of the liver can lead to cancer, medical investigators have only now begun to fully appreciate how the disruption of molecular signaling sets the stage for virus-induced liver cancer.

In an elegant series of cellular studies, scientists have found that a transmembrane enzyme (a protein embedded in the cell with active portions above and below the cell surface) plays a powerful role in damaging liver cells.

That enzyme goes by the name of hepsin, and is produced by the host. It increases vulnerability to liver cancer because it's a noteworthy turncoat—a biological traitor—when active in the milieu of a viral infection. Although the research team saw the damaging activity in the lab when two types of viruses, Sendai and herpes, were studied, the major global health crisis involving liver infections and cancer are centered squarely on hepatitis B and C.

Hepsin, as it turns out, doesn't even mess with the viruses themselves to create havoc in the liver; it irrevocably damages a protective protein called STING. Once STING is crippled, viruses are free to run roughshod through the liver.

Fu Hsin et al, The transmembrane serine protease hepsin suppresses type I interferon induction by cleaving STING, Science Signaling (2021). DOI: 10.1126/scisignal.abb4752

https://medicalxpress.com/news/2021-08-turncoat-protein-viruses-rou...

Comment by Dr. Krishna Kumari Challa on August 24, 2021 at 12:15pm

Some Rare Diamonds Form Out of The Remains of Once-Living Creatures

New research has discovered that two different types of rare diamonds share a common origin story – the recycling of once-living organisms over 400 kilometers (250 miles) below the surface.

There are three main types of natural diamonds. The first are lithospheric diamonds, which form in the lithospheric layer around 150 to 250 kilometers (93 - 155 miles) below the surface of Earth. These are by far the most common.

Then there are two rarer types - oceanic and super-deep continental diamonds.

Oceanic diamonds are found in oceanic rocks, while deep continental diamonds are those formed between 300 and 1,000 kilometers (186 and 621 miles) below the surface of Earth.

 oceanic and super-deep continental diamonds seem pretty different. Because variation in a carbon isotope signature called δ¹³C (delta carbon thirteen) can be used to determine whether the carbon has an organic or inorganic origin, past researchers have suggested that oceanic diamonds originally formed from organic carbon that was once within living beings.

Super-deep continental diamonds, on the other hand, have an extremely variable amount of δ¹³C. It's hard to tell whether they're made of organic carbon or not.

But in this new paper, led by Curtin University geologist Luc Doucet, the team found that the cores of super-deep continental diamonds have a similar δ¹³C composition. Surprisingly, this means that, like oceanic diamonds, these gems also contain the remains of once-living creatures.

https://www.nature.com/articles/s41598-021-96286-8

https://www.sciencealert.com/rare-diamonds-are-actually-made-of-onc...

Comment by Dr. Krishna Kumari Challa on August 24, 2021 at 11:04am

Some researchers have proposed that the brain does not measure the time we have spent awake – rather, it tracks how hard the brain works while we’re awake, and adjusts the amount of sleep we need accordingly. Research in support of this theory has found that individual areas of cortex can briefly switch off when overworked, even while the rest of the brain is still awake. This temporary shutdown of individual brain areas is termed “local sleep” and thought to be a mechanism that allows the brain’s cells to recover. While a person might not notice it, such a localised shutdown can profoundly affect someone’s performance – for example while driving a car.

But our brain would be very inefficient if individual parts of the cortex often went into local sleep whenever they felt they needed to. This is why it’s thought that the cortex may not only generate local sleep, but also activate the main sleep centres.

. Suppressing sleep might be dangerous, as sleep serves several essential, but still poorly understood, functions in our body and brain – such as memory processing, and making sure our immune system and metabolism function properly. But for many of us who struggle to feel tired and fall asleep, manipulating the cortex could become a way of triggering sleep when we’re struggling to nod off.

https://theconversation.com/feeling-tired-heres-how-the-brains-inte...

part 2

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