Why Some People Are Naturally Immune To HIV

Why Some People Are Naturally Immune To HIV:

With any virus, even devastating ones like Ebola and HIV, there are people who are exposed, often repeatedly, but somehow they never become infected or develop symptoms of disease. Though doctors have long wondered why, especially in the case of HIV, only today has a team of researchers found an explanation. Scientists at the University of Minnesota studying HIV-1 discovered some people have a specific variation of a gene, APOBEC3H, which produces an antiretroviral protein that inhibits the replication of HIV.

“We have seven APOBEC3 genes within the variants of human population,” Dr. Reuben S. Harris, a professor in the department of Biochemistry, Molecular Biology and Biophysics, explained to Medical Daily. Of these seven genes, “only APOBEC3H varies within the human population,” Harris added. APOBEC3H itself has seven variations, and if you broadly group these into those that make stable and those that make unstable proteins, Harris told Medical Daily, “What we found is those that are stable confer resistance to some forms of HIV.”

This important finding may pave the way to new treatments and drugs.

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Genetically Modified Bacteria Conduct Electricity, Ushering in New Era of Green Electronics

Genetically Modified Bacteria Conduct Electricity, Ushering in New Era of Green Electronics:

Researchers at the University of Massachusetts at Amherst have genetically modified common soil bacteria to produce nanowires capable of conducting electricity at a level that surprised even the scientists themselves. After years of skepticism that this was even theoretically possible, the practical demonstration could lead to a new generation of “green” electronics in which nanowires could be produced in plant waste, without the need for toxic chemicals.

The research, which was supported by the Office of Naval Research (ONR), goes back to a series of papers that Derek Lovley, a professor at UM Amherst, published back in 2011. Lovely overcame skeptics who claimed it was impossible for soil bacteria to conduct electricity. Brushing aside computer models indicating that it was impossible to make the bacteria into electrically conductive nanowires, Lovley demonstrated through experiments that it was indeed possible.

“Research like Dr. Lovley’s could lead to the development of new electronic materials to meet the increasing demand for smaller, more powerful computing devices,” said Linda Chrisey, a program officer in ONR’s Warfighter Performance Department, in a press release. “Being able to produce extremely thin wires with sustainable materials has enormous potential application as components of electronic devices such as sensors, transistors and capacitors.”

The bacteria that Lovley has used in his experiments are called Geobacters; they possess nanoscale protein filaments extending outward from their bodies. These protein filaments are the key to the bacteria’s growth, as they allow it to make electrical connections to the iron oxide contained in the soil where it lives. While these connections allow the Geobacter to survive, it was believed that they could never be made to conduct electricity to the extent that it would ever be useful for human interests, namely electronics.

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DNA revelations from Ötzi the Iceman’s leather and furs

5,300-year-old mummy found in the Italian Alps wore clothes made from many different animals. sci tech news

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How Sunflowers Follow the Sun, Day After Day

How Sunflowers Follow the Sun, Day After Day:

At dawn, whole fields of sunflowers stand at attention, all facing east, and begin their romance with the rising sun. As that special star appears to move across the sky, young flowers follow its light, looking up, then over and westward, catching one final glance as the sun disappears over the horizon.

At night, in its absence, the sunflowers face east again, anticipating the sun’s return.

They do this until they get old, when they stop moving. Then, always facing east, the old flowers await visits from insects that will spread their pollen and make new sunflowers. Those flowers too, will follow the sun.

It’s not love. It’s heliotropism, and sunflowers are not the only plants that track the sun. But until now, how sunflowers do it has been a mystery.

In a study published Friday in Science, researchers revealed that the sunflower’s internal clock and ability to detect light work together, turning on genes related to growth at just the right time to allow the stems to bend with the arc of the sun. The research team also showed that when fully grown, as tall as people in some cases, plants that always face east get a head start, warming up early to attract pollinators.

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Scientists have just uncovered a major difference between DNA and RNA

Scientists have just uncovered a major difference between DNA and RNA:

A new study has shown for the first time that RNA – the older molecular cousin of DNA – splits apart when it tries to incorporate change, while DNA can contort itself and change its shape to compensate for any chemical damage.

The research could finally explain why the blueprint of life is made from DNA and not RNA – and it could also prompt a rewrite of the textbooks.

“For something as fundamental as the double helix, it is amazing that we are discovering these basic properties so late in the game,” said lead researcher Hashim Al-Hashimi from the Duke University School of Medicine. “We need to continue to zoom in to obtain a deeper understanding regarding these basic molecules of life.”

Back in 1953, Watson and Crick first published their model of the DNA double helix, and predicted how the base pairs – A & T and G & C – fit together.

You’re probably pretty familiar with that formation by now – two strands of DNA are linked up by the bonding of the base pairs, forming ladder rungs that hold together the twisted ladder of DNA.

But researchers struggled to find evidence that the base pairs were bonding in the way that Watson and Crick had predicted – something they called Watson-Crick base pairs. Then in 1959, biochemist Karst Hoogsteen managed to take a picture of an A–T base pair, showing a slightly more skewed geometry, with one base rotated 180 degrees relative to the other.

Since then, researchers have observed both Watson-Crick and Hoogsteen base pairs in images of DNA.

But five years ago, Al-Hashimi and the Duke team found something that had never seen before: DNA base pairs constantly morphing back and forth between Watson-Crick and the Hoogsteen bonding configurations. This adds a whole other dimension and level of flexibility to DNA’s structure.

It turns out that DNA appears to be using Hoogsteen bonding when there’s a protein bond to a DNA site – or if there’s chemical damage to any of its bases – and once the damage is fixed or the protein is released, the DNA goes back to Watson-Crick bonds.

That discovery was a big deal in itself, but now the team has shown for the first time that RNA doesn’t have this ability, which could explain something that scientists have puzzled over for years: why DNA forms the blueprint for life, not RNA.

So, while DNA will absorb chemical damage and adapt to work around it, RNA becomes too stiff and falls apart, making DNA the better structure to pass genetic information down between the generations.

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‘Red gene’ in birds and turtles suggests dinosaurs had bird-like color vision

‘Red gene’ in birds and turtles suggests dinosaurs had bird-like color vision:

Earlier this year, scientists used zebra finches to pinpoint the gene that enables birds to produce and display the colour red.

Now, a new study shows the same ‘red gene’ is also found in turtles, which share an ancient common ancestor with birds. Both share a common ancestor with dinosaurs.

The gene, called CYP2J19, allows birds and turtles to convert the yellow pigments in their diets into red, which they then use to heighten colour vision in the red spectrum through droplets of red oil in their retinas.

Birds and turtles are the only existing tetrapods, or land vertebrates, to have these red retinal oil droplets. In some birds and a few turtle species, red pigment produced by the gene is also used for external display: red beaks and feathers, or the red neck patches and rims of shells seen in species such as the painted turtle.

The scientists mined the genetic data of various bird and reptile species to reconstruct an evolutionary history of the CYP2J19 gene, and found that it dated back hundreds of millions of years in the ancient archelosaur genetic line – the ancestral lineage of turtles, birds and dinosaurs.

The findings, published today in the journal Proceedings of the Royal Society B, provide evidence that the ‘red gene’ originated around 250 million years ago, predating the split of the turtle lineage from the archosaur line, and runs right the way through turtle and bird evolution.

Scientists say that, as dinosaurs split from this lineage after turtles, and were closely related to birds, this strongly suggests that they would have carried the CYP2J19 gene, and had the enhanced ‘red vision’ from the red retinal oil.

This may have even resulted in some dinosaurs producing bright red pigment for display purposes as well as colour vision, as seen in some birds and turtles today, although researchers say this is more speculative.

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Tolerance of smoke may have given us an edge over Neanderthals

Tolerance of smoke may have given us an edge over Neanderthals:

Where there’s fire there’s often smoke – which might have been bad news for Neanderthals and other ancient hominins. Modern humans carry a genetic mutation that reduces our sensitivity to cancer-causing chemicals found in wood smoke. But Neanderthals and Denisovans apparently lacked the mutation.

Harnessing fire was one of the key events in hominin prehistory. Fire offered light, warmth, better protection from predators and the possibility of easier-to-digest cooked food. But smoke is something to be wary of. “Even today, smoke inhalation increases susceptibility to lung infections,” says Gary Perdew at Pennsylvania State University.

It might have been a significant problem during the Stone Age, given that hominins often lighted fires in caves or other enclosed areas. “If you were in a cave trying to cook, the amount of smoke you’d breathe in would be ridiculous,” says Perdew.

Our species, Homo sapiens, might have been particularly well suited to those conditions, though. Perdew and his colleagues looked at the genomes of three Neanderthals and a Denisovan, and compared them with genomes from living people and one member of our species who lived 45,000 years ago.

The researchers found that this ancient member of our species already carried a mutation not seen in either Neanderthals or Denisovans. It occurs in the AHR gene, which produces a receptor that helps regulate our response to carcinogenic polycyclic aromatic hydrocarbons often found in wood smoke.

The team inserted human and Neanderthal versions of the AHR gene into animal cells in the lab and examined how the cells responded when exposed to these carcinogens. The Neanderthal version proved to be far more likely to cause the production of enzymes that induce a toxic effect.

“We were surprised that the differences between the two were so large,” says Perdew. For some compounds there was a 1000-fold difference in the toxic response.

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English bulldogs are at a genetic dead end, study finds

English bulldogs are at a genetic dead end, study finds:

Researchers have found evidence to suggest that English bulldogs – a breed known for short snouts and tiny, wrinkled bodies – are so genetically similar to one another, it’s impossible for breeders to make them healthier.

This ‘genetic dead end’ means that breeders will likely have to breed bulldogs – the fourth most popular breed in America – with different breeds if they want future generations to continue without major health issues.

“The English bulldog has reached the point where popularity can no longer excuse the health problems that the average bulldog endures in its often brief lifetime,” team leader Niels Pedersen from the University of California, Davis School of Veterinary Medicine, said in a statement.

“More people seemed to be enamoured with its appearance than concerned about its health. Improving health through genetic manipulations presumes that enough diversity still exists to improve the breed from within, and if not, to add diversity by outcrossing to other breeds,” he said. “We found that little genetic ‘wiggle room’ still exists in the breed to make additional genetic changes.”

The team examined 102 English bulldogs – 87 from the US and 15 from elsewhere around the world – and made genetic comparisons to a set of 37 other English bulldogs that were brought to the UC Davis School of Veterinary Medicine because of health issues.

They found that the bulldogs lacked that genetic diversity needed for breeders to selectively breed individuals with healthier phenotypes, which means there’s little hope for breeders to create a healthier bulldog unless they crossbreed them.

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Welcome to the age of ancient DNA sequencing

New tech gives us a sharper view of how people lived 12,000 years ago. sci tech news

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