Comment

Comment by Dr. Krishna Kumari Challa on March 21, 2024 at 7:19am

What are retroviruses?

A retrovirus is a type of RNA virus. RNA viruses have genes encoded in RNA instead of DNA. Like other viruses, retroviruses need to use the cellular machinery of the organisms they infect to make copies of themselves. Infection by a retrovirus, however, requires an additional step.

Retroviruses are "retro" because they reverse the direction of the normal gene-copying process. Usually, cells convert DNA into RNA so that it can be made into proteins. But with retroviruses, the process has to start by going backward.

A retrovirus replicates itself by first reverse-coding its genes into the DNA of the cells it infects. It does this with an enzyme called reverse transcriptase.

Retroviruses use reverse transcriptase to transform their single-stranded RNA into double-stranded DNA. DNA molecules store the genetic information of human cells and cells from other life forms.

Once transformed from RNA to DNA, the viral DNA is integrated into the genome of the infected cells. When this happens, the cells are tricked into copying these genes as part of the normal replication process.

The cell can also transcribe the DNA back into RNA as the first step in making viral proteins.

Retroviruses are sometimes used as gene delivery methods in gene therapy. This is because these viruses are both easy to modify and easily integrated into the host genome.

This means that, in theory, retroviruses can be used to make cellular machinery to produce proteins in an ongoing way. For example, scientists have used retroviruses to help diabetic rats make their own insulin.

Many retroviruses have been identified that infect non-human animals. Only a few retroviruses are known to cause illness in human beings, however. The most well-known of these are HIV and human T-cell lymphotropic virus.

Part 4

Comment by Dr. Krishna Kumari Challa on March 21, 2024 at 7:10am

Myelin is a coating of fat and protein that encases long nerve fibers known as axons. The coating works a bit like the insulation around an electrical wire: Nerves sheathed in myelin can send electrical signals faster than uninsulated nerves can.

Coated nerve fibers can also be thinner and grow longer than they would without insulation, enabling animals to grow bigger. And thinner fibers can be packed into the nervous system more efficiently.

As a result of myelin, brains became more complex and vertebrates became more diverse. If myelination hadn’t happened in early vertebrate evolution, we wouldn’t have the whole galaxy of vertebrate diversity that we see now.

T. Ghosh et al. A retroviral link to vertebrate myelination through retrotransposon.... Cell. Published online February 15, 2024. doi: 10.1016/j.cell.2024.01.011.

Part 3

Comment by Dr. Krishna Kumari Challa on March 21, 2024 at 7:08am

Ancient viruses helped speedy nerves evolve

The trick happened multiple independent times in jawed animals

One particular retrovirus — embedded in the DNA of jawed vertebrates — helps turn on production of a protein needed to insulate nerve fibers, researchers report February 15 in Cell. Such insulation, called myelin, may have helped make speedy thoughts and complex brains possible.

The retrovirus trick was so handy, in fact, that it showed up many times in the evolution of vertebrates with jaws, the team found.

Retroviruses are RNA viruses that make DNA copies of themselves to embed in a host’s DNA. Rarely, these insertions can become a permanent part of who we are, being passed down from parent to offspring. Scientists once thought remnants of of these ancient viruses — known as jumping genes or retrotransposons — as genetic garbage, but that impression is changing.

 Scientists are finding more and more evidence that these retrotransposons and retroviruses have influenced the evolution of life on the planet.

Remains of retroviruses were already known to have aided the evolution of the placenta, the immune system and other important milestones in human evolution . Now, they’re implicated in helping to produce myelin.

Part 2

Comment by Dr. Krishna Kumari Challa on March 21, 2024 at 7:04am

Virus helped brain evolution
Remnants of an ancient viral infection are essential for producing myelin, a protein that insulates nerve fibres, in most vertebrates. Certain viruses insert DNA into the genetic material of the cells they invade. Sometimes, these insertions become permanent and even aid evolutionary processes. Myelin helps nerves to send electrical signals faster, grow longer and thinner so they can be packed in more efficiently. “As a result of myelin, brains became more complex and vertebrates became more diverse,” says stem-cell biologist and study co-author Robin Franklin.

Part 1

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 12:58pm

In 2014, a similar kind of genetic modification was achieved in mice, whose milk contained up to 8.1 grams per liter of human proinsulin. Comparable concentrations were not reported in this new study, but that hasn't stopped Wheeler from thinking about scaling up.

A typical unit of insulin is 0.0347 milligrams, so if, as Wheeler proposes, each cow could make one gram of insulin per liter of milk, that's 28,818 units of insulin.

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.10...

Part 2

**

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 12:58pm

Scientists Engineer Cow That Makes Human Insulin Proteins in Its Milk

A genetically modified cow has produced proteins needed for human insulin in its milk, and the scientists behind the experiment have high hopes that a herd of these cattle could solve the world's insulin supply problems.

If such a herd were viable – and, based on this first case, that's still a long way off – the researchers think it could out-compete current insulin production methods, which rely on genetically modified yeast and bacteria.

While turning to cows for human insulin supply isn't new, the new study is the first time 'human' insulin production has been achieved in a genetically modified bovine.

Researchers inserted a particular segment of human DNA that codes for proinsulin (a protein that's converted to insulin) into the cell nuclei of 10 cow embryos, which were then inserted into the wombs of normal cows. Only one of these genetically modified embryos developed into a pregnancy, leading to the natural birth of a living, transgenic calf. When it reached maturity, the team made a variety of attempts to get the genetically modified cow pregnant, by artificial insemination, in vitro fertilization, and even the old-fashioned way. None were successful, but the team notes this may be more to do with how the embryo was created than the fact it was genetically modified. 

Eventually they were able to get the cow to lactate via hormonal induction, using an undisclosed method .

The cow didn't lactate as much as it would during a pregnancy, but what little milk it did produce over a month was examined to look for specific proteins, using western blotting and mass spectrometry.

The blotting revealed two bands with similar molecular masses to human proinsulin and insulin, which were not present in the milk of non-transgenic cows. Mass spectrometry indicated the presence of the C-peptide that's removed from human proinsulin in the process of creating insulin, which suggests that enzymes in the cow's milk may have converted the 'human' proinsulin into insulin.

Part 1

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 12:34pm

Science behind once-in-a-lifetime nova outburst that will light up the sky this year

The total solar eclipse isn't the only reason to keep your eyes to the sky this year. For the first time in 80 years, a star system 3,000 light years away will be visible to the naked eye thanks to a once-in-a-lifetime nova outburst.

NASA announced that the nova, which will create a "new" star in the night sky, will light up the night sky some time between now and September and be as bright as the North Star. One of only five recurring novae in our galaxy, it will be visible for a week before it fades back down.

What is nova?

There's a broad class of these sorts of events, and they typically share the trait of having two objects, or sometimes more than two objects, close to each other, and you're transferring mass from one to the other. Eventually, you build up enough mass on usually the hotter object that it ignites, in this case undergoing fusion, and then suddenly you get a very rapid release of energy so it gets much, much brighter.

The star system in question is T Coronae Borealis, or T CrB, and it contains a white dwarf and red giant, two stars that create the perfect conditions for a nova outburst.

A red giant is what happens when a star, like our sun, runs out of fuel and becomes larger and cooler, turning red instead of the white or yellow of a hot star. A white dwarf is what a red giant turns into when it runs out of even more fuel: a very compact star.

What happens when these two stars co-orbit one another is that the white dwarf steadily strips away the atmosphere of the expanding red giant. The white dwarf is much smaller and much more compact, so you build up a little disk of mostly hydrogen and maybe some helium as well sitting on the white dwarf.

Eventually enough of it builds up and basically ignites. It's not literally burning in the sense of fire; it's thermonuclear burn and you have hydrogen undergoing a fusion reaction.

As it undergoes that runaway thermonuclear reaction, the white dwarf gets hotter, bigger and brighter, making it easier for us to see it back on Earth. This entire process is part of the natural lifecycle of these stars and why they happen every 80 years. After a white dwarf like this goes nova, it goes back to stripping gas away from the red giant, building up gas at the same rate before eventually another outburst occurs.

https://news.northeastern.edu/2024/03/18/nova-explosion-new-star/

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 12:25pm

Admittedly, holograms were invented for a completely different purpose, to increase the resolution of electronic microscopy.
According to the scientists, the breakthrough of holograms in the fight against counterfeiting came when it was realized that once the original hologram was recorded, it could be copied mechanically by pressing it into another material. This has led to a substantial expansion in the production quantities of holograms.

Fictional films and their holograms of people and even entire cities have led to a rather diverse perception and interpretation of the term itself. The rapid advances in technology have allowed some fictional ideas to become reality, and today, even holograms in full concert arenas can be seen.
When strengthening the protective measures themselves, researchers encourage consumers to keep in mind that holograms can also be counterfeited, so he encourages everyone to inspect the holographic security labels and to remain alert.
Hologram manufacturers usually try to make holograms as bright as possible; the visible features, such as clear objects and different colors, do not glow by chance. Only specific elements of the brand are integrated into the image with different sizes of characters visible. If an observer sees a random glow, it is likely to be either a very unsophisticated hologram or a fake.
The inventors have developed another innovation. It is a digital application for smart devices called "HoloApp", which allows you to see what the hologram looks like on the screen. This enables a better understanding and experience of what a hologram should look like and the ability to identify if it is forged.

Patent filing: worldwide.espacenet.com/patent … 888B2?q=US11846888B2

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 12:22pm

Combating counterfeiting: Advanced hologram protection invented

Counterfeiting of various documents, banknotes, or tickets is a common problem that can be encountered in everyday life, even when shopping. Recognizing the scale and seriousness of the problem, researchers decided to look for ways to further reduce the risk of counterfeiting by inventing a new method to produce holographic security labels.

Holograms have been used as an anti-counterfeiting tool for some time. Now, they can be seen on pharmaceutical packaging, brand labels, and even toys. Holograms are much more difficult for forgers to counterfeit than, for example, the watermarks on banknotes, as they require complex micro and nano technologies that traditional printing houses lack.

Combining two technologies has led to international recognition

To enhance the level of holographic protection against forgery and to address this worldwide problem, Lithuanian researchers from KTU Institute of Materials Science came up with the idea of combining two technologically different methods.

One of them is a dot-matrix hologram made of small dots that refract light. "Each dot, which is barely smaller than a human hair, records a periodic structure made up of lines known as a diffraction grating. It causes the light to play in a way that is visible to the observer's eye, similar to a CD or DVD. This dot-matrix hologram, although relatively faster and cheaper and used to expose large areas of the hologram, does not guarantee a very high level of protection.

This is why electron beam lithography is used to expose smaller areas of the hologram. It is a more advanced technology that allows to form high-resolution structures and is practically inaccessible to potential hologram counterfeiters.

The combination of these two techniques has received international recognition—the invention has been recognized by the US Patent and Trademark Office and the Japanese Patent Office. This protects the intellectual property created by the scientists and allows them to license it to interested companies.
In addition, holographic label technologies developed by researchers now are already widely used for metrological verification on car license plates, on the packaging of various products, and on event tickets and diplomas.
Part 1

Comment by Dr. Krishna Kumari Challa on March 20, 2024 at 11:32am

That's bad news for many materials, but it wreaks particular havoc on plastics when combined with heat. The combined effects of rising temperature and moisture create very challenging conditions for these polymers.

Xin-Feng Wei et al, Plastic pollution amplified by a warming climate, Nature Communications (2024). DOI: 10.1038/s41467-024-46127-9

part 2

• ‹ Previous
• 1
• …
• 231
• 232
• 233
• 234
• 235
• …
• 1053
• Next ›
• Page