Science club

New cause of cell aging discovered

scienceclub — Fri, 26 Jul 2019 05:32:19 GMT

New cause of cell aging discovered

New research from the USC Viterbi School of Engineering could be key to our understanding of how the aging process works. The findings potentially pave the way for better cancer treatments and revolutionary new drugs that could vastly improve human health in the twilight years.

The work, from Assistant Professor of Chemical Engineering and Materials Science Nick Graham and his team in collaboration with Scott Fraser, Provost Professor of Biological Sciences and Biomedical Engineering, and Pin Wang, Zohrab A. Kaprielian Fellow in Engineering, was recently published in the Journal of Biological Chemistry.

"To drink from the fountain of youth, you have to figure out where the fountain of youth is, and understand what the fountain of youth is doing," Graham said. "We're doing the opposite; we're trying to study the reasons cells age, so that we might be able to design treatments for better aging."

What causes cells to age?

To achieve this, lead author Alireza Delfarah, a graduate student in the Graham lab, focused on senescence, a natural process in which cells permanently stop creating new cells. This process is one of the key causes of age-related decline, manifesting in diseases such as arthritis, osteoporosis and heart disease.

"Senescent cells are effectively the opposite of stem cells, which have an unlimited potential for self-renewal or division," Delfarah said. "Senescent cells can never divide again. It's an irreversible state of cell cycle arrest."

The research team discovered that the aging, senescent cells stopped producing a class of chemicals called nucleotides, which are the building blocks of DNA. When they took young cells and forced them to stop producing nucleotides, they became senescent, or aged.

"This means that the production of nucleotides is essential to keep cells young," Delfarah said. "It also means that if we could prevent cells from losing nucleotide synthesis, the cells might age more slowly."

Graham's team examined young cells that were proliferating robustly and fed them molecules labeled with stable isotopes of carbon, in order to trace how the nutrients consumed by a cell were processed into different biochemical pathways.

Scott Fraser and his lab worked with the research team to develop 3D imagery of the results. The images unexpectedly revealed that senescent cells often have two nuclei, and that they do not synthesize DNA.

Before now, senescence has primarily been studied in cells known as fibroblasts, the most common cells that comprised the connective tissue in animals. Graham's team is instead focusing on how senescence occurs in epithelial cells, the cells that line the surfaces of the organs and structures in the body and the type of cells in which most cancers arise.

Graham said that senescence is most widely known as the body's protective barrier against cancer: When cells sustain damage that could be at risk of developing into cancer, they enter into senescence and stop proliferating so that the cancer does not develop and spread.

"Sometimes people talk about senescence as a double-edged sword, that it protects against cancer, and that's a good thing," Graham said. "But then it also promotes aging and diseases like diabetes, cardiac dysfunction or atherosclerosis and general tissue dysfunction," he said.

Graham said the goal was not to completely prevent senescence, because that might unleash cancer cells.

"But then on the other hand, we would like to find a way to remove senescent cells to promote healthy aging and better function," he said.

Graham said that the team's research has applications in the emerging field of senolytics, the development of drugs that may be able to eliminate aging cells. He said that human clinical trials are still in early stages, but studies with mice have shown that by eliminating senescent cells, mice age better, with a more productive life span.

"They can take a mouse that's aging and diminishing in function, treat it with senolytic drugs to eliminate the senescent cells, and the mouse is rejuvenated. If anything, it's these senolytic drugs that are the fountain of youth," Graham said.

He added that in order for successful senolytic drugs to be designed, it was important to identify what is unique about senescent cells, so that drugs won't affect the normal, non-senescent cells.

"That's where we're coming in -- studying senescent cell metabolism and trying to figure out how the senescent cells are unique, so that you could design targeted therapeutics around these metabolic pathways," Graham said.

Meet India’s starry dwarf frog — a species with no close relatives

scienceclub — Tue, 19 Mar 2019 06:00:35 GMT

Meet India’s starry dwarf frog — a species with no close relatives

The new frog represents a new species, genus and potentially even a new family

A tiny new frog species discovered in tropical forests of southwest India has been one of a kind for millions of years.

Palaniswamy Vijayakumar and his colleagues first spotted the new species one night in 2010 while surveying frogs and reptiles roughly 1,300 meters up in India’s Western Ghats mountain range. The frog hardly stood out — its brown back, orange belly and starlike spots acted as camouflage against the dark hues and water droplets on the forest floor. And at only 2 to 2.9 centimeters long, “it can sit on your thumb,” says Vijayakumar, a biogeographer at George Washington University in Washington, D.C.

Dubbed the starry dwarf frog by the team, the frog didn’t seem special among the dozens of other possibly new species discovered on the trip. But analysis of its DNA, anatomy and geographic distribution told a different story. The frog represents the sole known species of a lineage dating back 57 million to 76 million years ago, the researchers report March 12 in PeerJ. That’s around when the Indian subcontinent was merging with Asia after breaking away from Madagascar.

“I had no clue I was holding onto a 50-million-year-old lineage,” Vijayakumar says. The researchers say the frog represents not just a new species and genus, but possibly even a new family, which they are working to confirm through genetic analysis and anatomical comparisons. “It’s a unique, old lineage without any close relatives” known to science, he says.

The team called the frog Astrobatrachus kurichiyana — with a genus name that includes “astro” for the frog’s bluish-white starlike dots, and species name that refers to the indigenous Kurichiyan people in the southern state of Kerala where the frog was found.

Astrophysicists Find New Clue in Search for Universe's Missing Matter

scienceclub — Mon, 18 Feb 2019 03:59:31 GMT

Astrophysicists Find New Clue in Search for Universe's Missing Matter

Astronomers think they've found a new clue in their continuing quest to solve one of the most substantial mysteries of the cosmos: where about a third of the universe's matter is hiding.

That missing matter isn't dark matter (a whole different head-scratcher), it's perfectly normal, run-of-the-mill matter that scientists simply can't find. And that makes it a massive cosmic annoyance for astronomers. But a team of researchers may have figured out a clue that will help them track down this missing matter, thanks to the NASA's Chandra X-ray Observatory.

"If we find this missing mass, we can solve one of the biggest conundrums in astrophysics," lead author Orsolya Kovács, a doctoral student at the Harvard Smithsonian Center for Astrophysics, said in a NASA statement. "Where did the universe stash so much of its matter that makes up stuff like stars and planets and us?" [Our X-Ray Universe: Amazing Photos by NASA's Chandra X-Ray Observatory]

Kovács and her research colleagues wanted to explore one popular theory: that the missing matter is hidden in the stringy filaments of warm gas that fill intergalactic space. Those filaments are typically hard to study, since telescopes tuned to the same light our eyes can see can't register these structures.

So the researchers came up with a work-around. They turned to Chandra's observations of a quasar called H1821+643, which produces a strong X-ray signal, figuring that if all that missing matter really is hiding in the intergalactic filaments, it would tweak the quasar's signal. Then they could work backward, comparing what they expected to what they saw.

They also tailored their search, homing in on specific wavelengths of X-ray light that they had determined would best show the effects of the filaments given the particular quasar they observed. That meant they could actually use the quasar's X-rays as a tool rather than simply being overwhelmed by its extremely bright emissions.

"Our technique is similar in principle to how you might conduct an efficient search for animals in the vast plains of Africa," Akos Bogdan, a co-author on the new research and an astrophysicist at the Harvard Smithsonian Center for Astrophysics, said in the same statement. "We know that animals need to drink, so it makes sense to search around watering holes first."

All told, the team identified 17 different filaments using this targeted approach. And the researchers used their observations to calculate how much mass was actually hiding in these filaments. Those calculations suggest that in this patch of the universe, at any rate, the missing mass is indeed hiding within these filament structures.

The research is described in a paper published Feb. 13 in The Astrophysical Journal.

Autopsy

scienceclub — Sat, 16 Feb 2019 08:44:38 GMT

Autopsy

Autopsy, also called necropsy, postmortem, or postmortem examination, dissection and examination of a dead body and its organs and structures. An autopsy may be performed to determine the cause of death, to observe the effects of disease, and to establish the evolution and mechanisms of disease processes. The word autopsy is derived from the Greek autopsia, meaning “the act of seeing for oneself.”

History Of Autopsy

The early Egyptians did not study the dead human body for an explanation of disease and death, though some organs were removed for preservation. The Greeks and the Indians cremated their dead without examination; the Romans, Chinese, and Muslims all had taboos about opening the body; and human dissections were not permitted during the Middle Ages.

The first real dissections for the study of disease were carried out about 300 BCE by the Alexandrian physicians Herophilus and Erasistratus, but it was the Greek physician Galen of Pergamumin the late 2nd century CE who was the first to correlate the patient’s symptoms (complaints) and signs (what can be seen and felt) with what was found upon examining the “affected part of the deceased.” This was a significant advance that eventually led to the autopsy and broke an ancient barrier to progress in medicine.

It was the rebirth of anatomy during the Renaissance, as exemplified by the work of Andreas Vesalius (De humani corporis fabrica, 1543) that made it possible to distinguish the abnormal, as such (e.g., an aneurysm), from the normal anatomy. Leonardo da Vinci dissected 30 corpses and noted “abnormal anatomy”; Michelangelo, too, performed a number of dissections. Earlier, in the 13th century, Frederick II ordered that the bodies of two executed criminals be delivered every two years to the medical schools, one of which was at Salerno, for an “Anatomica Publica,” which every physician was obliged to attend. The first forensic or legal autopsy, wherein the death was investigated to determine presence of “fault,” is said to have been one requested by a magistrate in Bologna in 1302. Antonio Benivieni, a 15th-century Florentine physician, carried out 15 autopsies explicitly to determine the “cause of death” and significantly correlated some of his findings with prior symptoms in the deceased. Théophile Bonet of Geneva (1620–89) collated from the literature the observations made in 3,000 autopsies. Many specific clinical and pathologic entities were then defined by various observers, thus opening the door to modern practice.

The autopsy came of age with Giovanni Morgagni, the father of modern pathology, who in 1761 described what could be seen in the body with the naked eye. In his voluminous work On the Seats and Causes of Diseases as Investigated by Anatomy, he compared the symptoms and observations in some 700 patients with the anatomical findings upon examining their bodies. Thus, in Morgagni’s work the study of the patient replaced the study of books and comparison of commentaries.

With Karl von Rokitansky of Vienna (1804–78), the gross (naked eye) autopsy reached its apogee. Rokitansky utilized the microscope very little and was limited by his own humoral theory. The French anatomist and physiologist Marie F.X. Bichat(1771–1802) stressed the role of the different generalized systems and tissues in the study of disease. It was the German pathologist Rudolf Virchow (1821–1902), however, who introduced the cellular doctrine—that changes in the cells are the basis of the understanding of disease—in pathology and in autopsy. He warned against the dominance of pathologic anatomy—the study of the structure of diseased tissue—alone as such and stressed that the future of pathology would be physiologic pathology—study of the functioning of the organism in the investigation of disease.

The modern autopsy has been expanded to include the application of all knowledge and all of the instruments of the specialized modern basic sciences. The examination has been extended to structures too small to be seen except with the electron microscope, and to molecular biology to include all that can be seen as well as what still remains unseen.

Procedure

The autopsy procedure itself has changed very little during the 20th century. The first step is a gross examination of the exterior for any abnormality or trauma and a careful description of the interior of the body and its organs. This is usually followed by further studies, including microscopic examination of cells and tissues.

The main incisions in the body remain the same. For the torso, a Y-shaped incision is made. Each upper limb of the “Y” extends from either the armpit or the outer shoulder and is carried beneath the breast to the bottom of the sternum, or breastbone, in the midline. From this point of juncture at the bottom of the sternum the incision is continued down to the lower abdomen where the groins meet in the genital area.

There are different schools as to procedure beyond this point. In one method, each organ is removed separately for incision and study. In the so-called en masse methods the chest organs are all removed in a single group and all of the abdominal organs in another for examination. The great vessels to the neck, head, and arms are ligated—tied off—and the organs removed as a unit for dissection. The neck organs are explored in situ only or removed from below. Dissection then proceeds usually from the back, except where findings dictate a variation in the procedure. Usually groups of organs are removed together so that disturbances in their functional relationships may be determined. After study of the brain in position, it is freed from its attachments and removed in toto. The spinal cord also can be removed.

The dissector proceeds to examine the external and cut surface of each organ, its vascular structures, including arteries, lymphatics, fascial or fibrous tissue, and nerves. Specimens are taken for culture, chemical analysis, and other studies. Immediately upon completion of the procedure, all of the organs are returned to the body and all incisions carefully sewn. After the body’s proper restoration, no unseemly evidence of the autopsy need remain.

After the gross examination of the body the findings are balanced one against another and a list of pathological findings is compiled; this list comprises the tentative or “provisional anatomical diagnoses.” Such diagnoses are grouped and arranged in the order of importance and of sequence. On occasion a quick microscopic study is done to confirm a diagnosis so as to assure its proper listing.

Autopsies document the disease processes that were in place at the time of the patient’s death, and most autopsies do not list an immediate or proximate cause of death. These factors are important in forensic cases, and they are often required in autopsy analysis even in situations when an autopsy itself is not required by law. After all studies—histological, chemical, toxicological, bacteriological, and viral—are completed, any errors of the provisional anatomical diagnoses are corrected and the final anatomical diagnoses and the final cause of death are listed. A statement of analysis of the autopsy that correlates the findings with the clinical picture, the “clinical pathological correlation,” concludes the record of the autopsy.

Forensic Autopsy

The forensic pathologist goes beyond the mere cause of death; he must establish all the facts, both lethal and nonlethal, with any potential bearing whatsoever on the criminal or civil litigation. The cause of death is not automatically revealed when the body is opened; it is not an isolated tangible and delimited entity; it is a concept—an opinion—as to mechanism or happening and as such is subject occasionally to differences in interpretation. The legal autopsy requires meticulous detailed descriptions, measurements, and documentation.

The goal of forensic autopsies is to determine whether or not death was due to natural causes. Experience in the investigation of the scene of a death in medicolegal cases is important, for the evaluation of circumstances of death may be critical in establishing the mode of death—e.g., suicide. The autopsy may not be able, of itself, to determine intent, whereas the scene and the circumstances may provide unmistakable evidence. Photographic documentation is important in the medicolegal autopsy. The medicolegal postmortem examination must always be complete to rule out any other potential contributory cause of death and therefore must never be limited to a partial study. The identification of the deceased and of all specimens taken from the body is critical; the time of death and the blood grouping must, if possible, be established. In all autopsies, but especially in forensic cases, findings must be dictated to a stenographer or recording instrument during the actual performance of the procedure. The record often becomes legal evidence and therefore must be complete and accurate.

Purposes

The autopsy deals with the particular illness as evidenced in one individual and is more than simply a statistical average. Every autopsy is important to expose mistakes, to delimit new diseases and new patterns of disease, and to guide future studies. Morbidity and mortality statistics acquire accuracy and significance when based on careful autopsies; they also often give the first indication of contagion and epidemics. Nor can the role of the autopsy in medical education be understated. It is the focal point at which the profession learns to assess and to apply medical knowledge. Thus, the autopsy does more than merely determine the cause of death. While the medicolegal autopsy in particular has this important primary objective, most autopsies have a larger purpose.

Neanderthals: Facts About Our Extinct Human Relatives

scienceclub — Fri, 07 Sep 2018 05:01:08 GMT

Neanderthals: Facts About Our Extinct Human Relatives

Neanderthals (or Neandertals) are our closest extinct human relatives. There is some debate as to whether they were a distinct species of the Homogenus (Homo neanderthalensis) or a subspecies of Homo sapiens. Our well-known, but often misunderstood, fossil kin lived in Eurasia 200,000 to 30,000 years ago, in the Pleistocene Epoch. They started to evolve 300,000 and 100,000 years ago, according to Encyclopedia Britannica.

Neanderthals' appearance was similar to ours, though they were shorter and stockier with angled cheekbones, prominent brow ridges and wide noses. Though sometimes thought of as dumb brutes, scientists have discovered that they used tools, buried their dead and controlled fire, among other intelligent behaviors. It is theorized that for a time, Neanderthals probably shared the Earth with other Homo species.

Discovery

In 1856, a group of quarrymen discovered remnants of a skeleton in the Neander Valley near Dusseldorf, Germany (hence their name). In a limestone cave, they found 16 pieces of bone, including a skull. Thinking the bones belonged to a bear, the quarrymen gave them to local teacher Johan Karl Fuhlrott. From him, the bones found their way to scientists, and it was eventually determined that they were ancient human relatives. The publication and popularization of Charles Darwin's "On the Origin of the Species" in 1859 helped inform the discovery. Since that day in the Neander Valley, more than 400 Neanderthal bones have been found.

The original cave men

Neanderthals lived during the Ice Age. They often took shelter from the ice, snow and otherwise unpleasant weather in Eurasia's plentiful limestone caves. Many of their fossils have been found in caves, leading to the popular idea of them as "cave men."

Like other humans, Neanderthals originated in Africa but migrated to Eurasia long before other humans did. Neanderthals lived across Eurasia, as far north and west as the Britain, through part of the Middle East, to Uzbekistan. Popular estimates put the peak Neanderthal population around 70,000, though some scientists put the number drastically lower, at around 3,500 females.

While humans may have interbred with Neanderthals long ago, the pairing probably only rarely produced offspring.

Credit: Mauro Cutrona

Their short, stocky stature was an evolutionary adaptation for cold weather, since it consolidated heat. According to the Smithsonian Institution, the wide nose helped humidify and warm cold air, though this assertion is debated. The American Museum of Natural History states that other differences from other humans are a flaring, funnel-shaped chest, a flaring pelvis, and robust fingers and toes. Approximately 1 percent of Neanderthals had red hair, light skin, and maybe even freckles.

Their brains, however, grew at slower rate than the brains of other humans' and became larger, according to research published in the September 2017 issue of the journal Science. "It took a little bit longer for the brain to grow in Neanderthals than in modern humans," said study co-lead author Antonio Rosas, chairman of the paleoanthropology group at Spain's National Museum of Natural Sciences in Madrid. "We thought our slow way of growing was very specific, very particular, very unique to our species," Rosas said. "What we realize now is that this pattern of slow growth that allows us to have this big brain and mature slowly, with all the advantages involved with that, was also shared by different human species."

Social structure

Neanderthals lived in nuclear families. Discoveries of elderly or deformed Neanderthal skeletons suggest that they took care of their sick and those who could not care for themselves. Neanderthals typically lived to be about 30 years old, though some lived longer. It is accepted that Neanderthals buried their dead, though whether or not they left carved bone shards as grave goods is debated.

It is not known if they had language, though the large size and complex nature of their brains make it a likely possibility.

Neanderthals used stone tools similar to the ones used by other early humans, including blades and scrapers made from stone flakes. As time went on, they created tools of greater complexity, utilizing materials like bones and antlers. Evan Hadingham of PBS's NOVA reported that Neanderthals used a type of glue, and later pitch, to attach stone tips to wooden shafts, creating formidable hunting spears.

Neanderthals had some control of fire, and it is even theorized that they built boats and sailed on the Mediterranean.

Neanderthals were primarily carnivorous, and the harsh climate caused them to resort occasionally to cannibalism. Recently, however, scientists have found that Neanderthals actually ate cooked vegetables fairly regularly.

Human-Neanderthal interbreeding

Probably the most debated aspect of Neanderthal life in recent years is whether or not they interbred with other human species. The answer remains ambiguous, with scholarly opinions ranging from belief that they definitely interbred to belief that the two groups didn't exist on Earth at the same time.

Neanderthal expert Erik Trinhaus has long promoted the interbreeding hypothesis, but the theory really caught fire when a 2010 study published in Science magazine determined that Neanderthal DNA is 99.7 percent identical to modern human DNA (a chimp's is 99.8 percent identical). Researchers of the Neanderthal Genome Project found that 2.5 percent of an average non-African human's genome is made up of Neanderthal DNA. The average modern African has no Neanderthal DNA. This information could support the interbreeding hypothesis because it suggests that Neanderthals and other species only bred once the other humans had moved out of Africa, into Eurasia, according to a 2012 paper published in the journal PLOS. They could have interbred as recently as 37,000 years ago.

Recent research published in the October 2017 issue of American Journal of Human Genetics found that genomes of modern human groups originating outside Africa contain between 1.8 and 2.6 percent Neanderthal DNA. "Neandertal DNA is one source of variation for many traits in modern humans," study lead author Michael Dannemann, a computational biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told Live Science. [Your Hair Color and Sleep Habits May Come from Neanderthals]

Another 2017 study by author Kay Prüfer, a paleogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, found that modern-human DNA entered the Neanderthal gene pool between 130,000 and 145,000 years ago. [You May Be More 'Neanderthal' Than You Thought]

If this interbreeding occurred, why don't modern humans carry more Neanderthal DNA? A possible reason involves the male sex chromosome. Scientists have found that the Neanderthal Y chromosome may have kept the two lineages from successfully interbreeding; the chromosome may have created conditions that frequently led to miscarriages if or when a Neanderthal male and modern human female got together, according to the research published in the April 7, 2016, issue of the American Journal of Human Genetics. In the study, Fernando Mendez, a population geneticist at Stanford University, and colleagues discovered three mutations on the Y chromosome of a Neanderthal male that would have produced molecules that can trigger immune responses from women during pregnancy. Those immune responses are linked to miscarriages.

A 2012 study, however, cast doubt on the interbreeding theory. Researchers re-examined bones from southern Spain that were used in earlier studies with new radiocarbon dating techniques. They discovered that the Neanderthal bones were more than 50,000 years old. Humans aren't believed to have settled in the area until 42,000 years ago, meaning that it may be unlikely that they lived together and interbred.

If humans and Neanderthals didn't interbreed, the similar genomes of humans and Neanderthals could be the result of both groups having a common African ancestor.

Extinction

No one knows exactly why Neanderthals went extinct and why Homo sapiens survived. Some scholars theorize that gradual or dramatic climate change led them to their demise, while others blame dietary deficiencies. Some theorize that humans killed the Neanderthals. Until recently the hypothesis that Neanderthals didn't go extinct but simply interbred with humans until they were absorbed into our species was popular.

This Plan to Bring Back an Extinct Ice-Age Horse Species Is an Extreme Long Shot, Scientists Say

scienceclub — Fri, 07 Sep 2018 04:52:17 GMT

This Plan to Bring Back an Extinct Ice-Age Horse Species Is an Extreme Long Shot, Scientists Say

A team of scientists in Siberia is hopeful that a mummified 40,000-year-old baby horse can provide critical genetic material for cloning the extinct ice-age species.

But experts told Live Science that they are skeptical that the scientists will be able to find viable DNA on the body at all, let alone overcome the enormous challenges of cloning a species that's been extinct for millennia.

Revived after millennia?

The preserved foal's body was discovered in August and was excavated from melting permafrost in the Batagaika crater in Yakutia, a region in eastern Russia. Researchers working with the frozen remains recently toldThe Siberian Times that they are investigating whether the remains will yield living cells that could be used to clone the ancient baby horse. [See Photos of the Perfectly Preserved Ice-Age Foal]

According to The Siberian Times, one of the scientists involved in the analysis of the mummified horse is Woo-Suk Hwang, a stem-cell researcher and cloning pioneer from South Korea. Hwang, a former professor at South Korea's Seoul National University, came under fire in 2006 for falsifying data, and was convicted three years later of bioethical violations and embezzlement, Nature reported in 2009. He now helms Sooam Biotech Research Foundation, a South Korean company that researches and performs animal cloning — primarily dogs, Live Science previously reported.

Scientists from Russia and South Korea — including Hwang — are already collaborating in an attempt to clone a woolly mammoth, and they are now exploring the possibility of extracting living cells from the preserved horse, which could potentially be used to create a clone, Hwang told The Siberian Times.

"If we find only one live cell, we can clone this ancient horse," Hwang said. "We can multiply it and get as many embryos as we need."

A mummified foal that lived between 30,000 and 40,000 years ago is superbly preserved, but intact DNA may still be elusive.

Credit: Michil Yakovlev/The Siberian Times

An extinct horse could prove easier to clone than a mammoth because a modern horse could serve as the embryo's surrogate, while a cloned mammoth embryo would need to be implanted in a female elephant, Hwang explained. Elephants are in the same family as extinct mammoths, but they are not close relatives — so a cloned "mammoth" would more likely be a genetically engineered elephant-mammoth hybrid, he said.

Nevertheless, cloning an extinct ice-age horse could be a step toward cloning a mammoth, as "it will help us to work out the technology," Hwang told The Siberian Times.

"Astronomical" odds

However, several scientists who were not involved with the analysis of the foal expressed doubts that it would be possible to successfully clone the mummified horse.

"Many of [the] same challenges will be faced here as with attempts to clone mammoths," Beth Shapiro, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, told Live Science in an email.

Cloning is possible only when the original animal's DNA is intact, and the majority — if not all — of the DNA in ice-age specimens is typically degraded "into tens of millions of pieces," Love Dalén, a professor of evolutionary genetics at the Swedish Museum of Natural History in Stockholm, told Live Science in an email.

If enough DNA from the mummified horse's remains can be recovered, scientists might be able to construct a genome sequence by comparing the DNA of the extinct foal to the genomes of living horses, Shapiro added.

But the chance of finding an undamaged nucleus with an intact genome, or even a frozen cell that could be recovered, "is astronomical," Vincent Lynch, an assistant professor in the Department of Human Genetics at the University of Chicago, told Live Science in an email.

"Scientists rarely say something is impossible, but it is certainly approaching it," Lynch said.

How Do Fossils Form?

scienceclub — Thu, 06 Sep 2018 10:01:57 GMT

How Do Fossils Form?

When animals, plants and other organisms die, they typically decay completely. But sometimes, when the conditions are just right, they're preserved as fossils.

Several different physical and chemical processes create fossils, according to the New York State Geological Survey.

Freezing, drying and encasement, such as in tar or resin, can create whole-body fossils that preserve bodily tissues. These fossils represent the organisms as they were when living, but these types of fossils are very rare.

Most organisms become fossils when they're changed through various other means.

The heat and pressure from being buried in sediment can sometimes cause the tissues of organisms — including plant leaves and the soft body parts of fish, reptiles and marine invertebrates — to release hydrogen and oxygen, leaving behind a residue of carbon.

This process — which is called carbonization, or distillation — yields a detailed carbon impression of the dead organism in sedimentary rock.

The most common method of fossilization is called permineralization, or petrification. After an organism's soft tissues decay in sediment, the hard parts — particularly the bones — are left behind.

Water seeps into the remains, and minerals dissolved in the water seep into the spaces within the remains, where they form crystals. These crystallized minerals cause the remains to harden along with the encasing sedimentary rock.

In another fossilization process, called replacement, the minerals in groundwater replace the minerals that make up the bodily remains after the water completely dissolves the original hard parts of the organism.

Fossils also form from molds and casts. If an organism completely dissolves in sedimentary rock, it can leave an impression of its exterior in the rock, called an external mold. If that mold gets filled with other minerals, it becomes a cast.

An internal mold forms when sediments or minerals fill the internal cavity, such as a shell or skull, of an organism, and the remains dissolve.

Organic remnants

In recent years, researchers have discovered that some fossils aren't just made of minerals. Fossil analyses have shown, for instance, that some retain organic material dated to the Cretaceous, a period that lasted from 65.5 million to 145.5 million years ago, and the Jurassic period, which lasted from 145.5 million to 199.6 million years ago

Tests suggest that these organic materials belong to dinosaurs because they match certain proteins from birds, which evolved from dinosaurs.

"It used to be that no one thought it was possible for any endogenous material — material that comes from the animal — could be left behind after the fossilization process," said Ken Lacovara, the dean of the School of Earth and Environment at Rowan University in New Jersey. "[But] that's not really the case."

It's unclear how the organic material is preserved, but iron might help the proteins become cross-linked and unrecognizable, or unavailable to the bacteria that would otherwise consume them, Lacovara said. (Formaldehyde works in a similar way, cross-linking the amino acids that make up proteins, making them more resistant to decay, Mary Schweitzer, a molecular paleontologist at North Carolina State University.

Another idea is "microbial masonry," Lacovara said. "It's possible that the bacteria that initially chomped through the tissue are secreting minerals as a waste product that then hermetically [airtight] seal a little bit of what remains behind," almost like a stone mason sealing off a structure, he told Live Science.

Moreover, sandstone — rock made of sand-size grains of minerals, sediments or inorganic material — seems to be the best type of environment for preserving organic material in fossils.

"Sandstone is like a bunch of volleyballs sitting on top of each other with big interstitial [spaced] areas between them," Lacovara said. "So it seems like rapid decay might promote the preservation process. Maybe we need the bacteria to get through fast and to chomp through the sediment so that they can sequester some of [the surviving organic material] in the process."

How Could a Diabetes Drug Cause Severe Genital Infections?

scienceclub — Thu, 06 Sep 2018 09:52:05 GMT

How Could a Diabetes Drug Cause Severe Genital Infections?

People with type 2 diabetes who take a certain class of drugs have a very troubling side effect to worry about: The drugs may increase the risk of the genitals becoming infected with "flesh-eating" bacteria.

On Wednesday (Aug. 29), the U.S. Food and Drug Administration (FDA) issued a warning about sodium-glucose cotransporter-2 (SGLT2) inhibitors, which are commonly prescribed medications for treating type 2 diabetes. Over a five-year period, the drugs have been linked to a dozen rare cases of genital infections that cause the skin to die, a condition called necrotizing fasciitis. All 12 patients who developed the infection were hospitalized, and one died, according to the FDA.

The infection is more common in men than women, and it can spread to other parts of the body, Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, told SELF. "It can rapidly progress and involve the entire genital area and even the abdominal wall," he said. [5 Ways Skin Can Signal Health Problems]

There have been enough instances of these severe infections that the FDA now requires all SGLT2 inhibitors to include a warning about this risk in their prescribing information. Medications in this class include canagliflozin, dapagliflozin, empagliflozin and ertugliflozin. The drugs are available as single-ingredient medications or in combinations, such as with metformin, the FDA said.

How do the infections happen?

Type 2 diabetes occurs when the body can't remove sugar from the bloodstream, because cells fail to respond to insulin, the hormone that helps move sugar into the cells. SGLT2 inhibitors work to lower blood sugar by causing the kidneys to remove sugar from the body through urine. This stabilizes blood sugar levels.

So, how can this lead to infections? Anywhere there is higher blood sugar, there's an increased chance of bacterial infection, Jamie Alan, an assistant professor of pharmacology and toxicology at Michigan State University, told SELF. "We have bacteria all over us, and one of the foods that bacteria likes is [sugar]," Alan said. She explained that eliminating more sugar through urine means there is more of bacteria's favorite food in the genital area, so this spot becomes a rather inviting environment for them.

The bacteria become a problem only if there is an entry point to infect, such as a small cut from shaving or a skin ulcer near the genitals. And that's exactly what happens, Adalja told SELF. The infections are serious and often require many surgeries to remove all the infected tissues, Adalja said. (All 12 patients described in the FDA warning required surgery.)

The FDA warning instructs patients taking the drugs to seek medical attention right away if they experience any signs of swelling, itching or irritation in the genitals area or have a fever above 100.4 degrees Fahrenheit (38 degrees Celsius) and generally don't feel well. The bacteria that cause necrotizing fasciitis can spread quickly, so it's important to seek treatment immediately.

But the infections are rare, and it's unwise to stop taking medications without talking it over with a doctor, Alan told SELF. There are other options for treating type 2 diabetes, she said, but practicing good hygiene can help minimize the risk of necrotizing fasciitis.

Nobel prize winners@2017

scienceclub — Tue, 24 Oct 2017 03:52:09 GMT

History of Nobel Prize

The foundation of Nobel Prize was laid by Alfred Nobel, on 27th November 1895.
Alfred Nobel was a Swedish chemist who invented Dynamite.
He signed his last testimony and gave away a large share of his possession and fortunes to a series of prizes in the fields of literature, physics, chemistry, physiology and peace.
A 6th prize, in economics, was established in 1968 by Sveriges Riksbank (the Swedish central bank) and is known as the Sveriges Riksbank Prize in Economic Sciences in memory of Alfred Nobel.
The first Nobel Prizes were awarded in the year 1901, which is five years after Nobel Alfred’s death.

Nomination for Nobel Prize

Nomination forms are sent by the Nobel Committee to about 3,000 individuals. It is basically done in September the year before the prizes are awarded.
The deadline for the return of the nomination forms is 31st January of the year of the award when it is to be presented.
Members of academies, university professors, scientists, ex-Nobel laureates along with members of parliamentary assemblies from various countries are asked to nominate candidates who are eligible to receive the award.
Then the Nobel Committee nominates about 300 potential Laureates from these forms and additional names.
These nominees are not named publicly, nor are they informed that they are being considered for the prize.
All nomination records for a prize are sealed for 50 years from the awarding of the prize.
The names of the candidates are then sent to Norwegian Nobel Committee in Oslo for consideration where winners are chosen through majority votes.

Nobel Prize Ceremonies

All Nobel Prizes are awarded in Stockholm, Sweden, except for the Nobel Peace Prize, which is awarded in Oslo, Norway.
Winners are announced at the beginning of October every year.
Nobel Winners receive their award from Swedish King.
For the ceremony, the gentlemen are required to wear white tie and tails, while ladies should be dressed in an evening gown.
Nobel laureates receive a Nobel diploma, a medal and 10 million Swedish crowns (INR 80846203.04) per prize.
The highlight of the Nobel Prize Award Ceremony in Stockholm is the moment when each Nobel laureate steps forward to receive the prize from the King of Sweden.

50 Year Secrecy Rule

Information in the Nobel Committee’s nominations is not published until after 50 years. Committee members are not allowed to spill out the names of the candidates nominated for the Nobel Prize.

Nobel Banquet

A banquet is held in the Blue Hall at the Stockholm City Hall after the award ceremony in Sweden which is attended by the Swedish Royal Family including 1,300 guests.
The Nobel Peace Prize banquet is held in Norway at the Oslo Grand Hotel right after the award ceremony.
Apart from the Laureate, the guests include the President of the Storting, the Prime Minister, and, since 2006, the King and Queen of Norway.

Nobel Lecture

Each Nobel Laureate is required to give a Public Lecture on a subject related to the topic of their prize according to the statutes of the Nobel Foundation.
The Nobel lecture took decades to reach its current format.
These lectures normally occur during Nobel Week, though this is not mandatory. The Laureate is only obliged to give the lecture within 6 months of receiving the prize. However, some of the lectures have happened even later.
For example, US President Theodore Roosevelt received the Peace Prize in 1906 but gave his lecture in 1910, after his term in office. The lectures are organised by the same association who have selected the Laureates.

Field	Name of Recipient	Work
Physics	Rainer Weiss, Barry C. Barish, Kip S. Thorne	Contributed to *LIGO detector* & the observation of gravitational waves
Chemistry	Jacques Dubochet, Joachim Frank, Richard Henderson	Developed cryo-electron microscopy for the high-resolution structure determination of bio-molecule in solution.
Physiology	Jeffrey C. Hall, Michael Rosbash, Michael W. Young	Discovered molecular mechanisms to control the circadian rhythm.
Literature	Kazuo Ishiguro	In his novels, uncovered the chasm beneath our *illusory* *sense of* *connection* *with the world*
Nobel Peace Prize	International Campaign to Abolish Nuclear Weapons (ICAN)	Made groundbreaking efforts to achieve a treaty-based on prohibition of nuclear weapons
The Sveriges Riksbank Prize in Economic Sciences	Richard H. Thaler	Contributed to *behavioural* economics.

Types of Nobel prizes: Medals, Diploma and Money

Medals

Nobel Prize medals are registered trademarks of the Nobel Foundation.
Each medal features an image of Alfred Nobel in left profile showing along with the years of his birth and death.
All medals made before 1980 were struck in 23-carat gold. But since then, they have been struck in 18-carat green gold plated with 24-carat gold.
The weight of each medal varies according to the value of gold. However, it averages about 175 grams for each medal.

Diplomas

Nobel Laureates receive a diploma from the King of Sweden.
In the case of the peace prize, it is received by the Chairman of the Norwegian Nobel Committee.
Each diploma is uniquely designed by the Prize-Awarding Institutions for the Laureates who receive them.
The diploma contains a picture and text in Swedish which states the name of the Laureate and usually a citation of the reason they received the prize.
None of the Nobel Peace Prize Laureates have ever had a citation on their diplomas.

Award Money

The Laureates are awarded a sum of money when they receive their prizes, in the form of a document confirming the amount awarded.
The amount of the prize money depends on how much money the Nobel Foundation is awardingeach year.

Now that you have gone through Nobel Prize Winners 2017 for Banking & SSC Exams, we hope you were benefited. Now all you have to do is run through the list carefully to easily memorize the names of the recipients and the contribution they have made in their respective fields.

Gut bacteria that 'talk' to human cells may lead to new treatments

scienceclub — Fri, 01 Sep 2017 09:48:29 GMT

Gut bacteria that 'talk' to human cells may lead to new treatments

We have a symbiotic relationship with the trillions of bacteria that live in our bodies -- they help us, we help them. It turns out that they even speak the same language. And new research from The Rockefeller University and the Icahn School of Medicine at Mt. Sinai suggests these newly discovered commonalities may open the door to "engineered" gut flora who can have therapeutically beneficial effects on disease.

"We call it mimicry," says Sean Brady, director of Rockefeller University's Laboratory of Genetically Encoded Small Molecules, where the research was conducted. The breakthrough is described in a paper published this week in the journal Nature.

In a double-barreled discovery, Brady and co-investigator Louis Cohen found that gut bacteria and human cells, though different in many ways, speak what is basically the same chemical language, based on molecules called ligands. Building on that, they developed a method to genetically engineer the bacteria to produce molecules that have the potential to treat certain disorders by altering human metabolism. In a test of their system on mice, the introduction of modified gut bacteria led to reduced blood glucose levels and other metabolic changes in the animals.

Molecular impersonation

The method involves the lock-and-key relationship of ligands, which bind to receptors on the membranes of human cells to produce specific biological effects. In this case, the bacteria-derived molecules are mimicking human ligands that bind to a class of receptors known as GPCRs, for G-protein-coupled receptors.

Many of the GPCRs are implicated in metabolic diseases, Brady says, and are the most common targets of drug therapy. And they're conveniently present in the gastrointestinal tract, where the gut bacteria are also found. "If you're going to talk to bacteria," says Brady, "you're going to talk to them right there." (Gut bacteria are part of the microbiome, the larger community of microbes that exist in and on the human body.)

In their work, Cohen and Brady engineered gut bacteria to produce specific ligands, N-acyl amides, that bind with a specific human receptor, GPR 119, that is known to be involved in the regulation of glucose and appetite, and has previously been a therapeutic target for the treatment of diabetes and obesity. The bacterial ligands they created turned out to be almost identical structurally to the human ligands, says Cohen, an assistant professor of gastroenterology in the Icahn School of Medicine at Mt. Sinai.

Manipulating the system

Among the advantages of working with bacteria, says Cohen, who spent five years in Brady's lab as part of Rockefeller's Clinical Scholars Program, is that their genes are easier to manipulate than human genes and much is already known about them. "All the genes for all the bacteria inside of us have been sequenced at some point," he says.

In past projects, researchers in Brady's lab have mined microbes from soil in search of naturally occurring therapeutic agents. In this instance, Cohen started with human stool samples in his hunt for gut bacteria with DNA he could engineer. When he found them he cloned them and packaged them inside E. coli bacteria, which is easy to grow. He could then see what molecules the engineered E. coli strains were making.

Although they are the product of non-human microorganisms, Brady says it's a mistake to think of the bacterial ligands they create in the lab as foreign. "The biggest change in thought in this field over the last 20 years is that our relationship with these bacteria isn't antagonistic," he says. "They are a part of our physiology. What we're doing is tapping into the native system and manipulating it to our advantage."

"This is a first step in what we hope is a larger-scale, functional interrogation of what the molecules derived from microbes can do," Brady says. His plan is to systematically expand and define the chemistry that is being used by the bacteria in our guts to interact with us. Our bellies, it turns out, are full of promise.