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Comment by Dr. Krishna Kumari Challa on March 30, 2016 at 7:11am

South Asians share ancestry with a mysterious population...
Many bloodlines around the world, particularly of South Asian descent, may actually be a bit more Denisovan- a mysterious population of hominids.
Denisovans lived around the same time as the Neanderthals - scientists have revealed. The team from Harvard Medical School and University of California-Los Angeles (UCLA) has created a world map and also used comparative genomics to make predictions about where Denisovan and Neanderthal genes may be impacting modern human biology. The analysis also proposes that modern humans interbred with Denisovans about 100 generations after their trysts with the Neanderthals.
Denisovan genes can potentially be linked to a more subtle sense of smell in Papua New Guineans and high-altitude adoptions in Tibetans.
Meanwhile, Neanderthal genes found in people around the world most likely contribute to tougher skin and hair. Most non-Africans possess at least a little bit Neanderthal DNA.
There was also negative selection to systematically remove ancestry that may have been problematic from modern humans. We can document this removal over the 40,000 years since these admixtures occurred.
They found evidence that both Denisovan and Neanderthal ancestry has been lost from the X chromosome as well as genes expressed in the male testes.
The team theorises that this has contributed to reduced fertility in males, which is commonly observed in other hybrids between two highly divergent groups of the same species.
The researchers collected their data by comparing known Neanderthal and Denisovan gene sequences across more than 250 genomes from 120 non-African populations publicly available through the Simons Genome Diversity Project.
The new map of archaic ancestry was published in the journal Current Biology.

Comment by Dr. Krishna Kumari Challa on March 24, 2016 at 10:15am

A Korean research team has engineered gut bacteria to create non-natural polymers in a biorefinery—allowing various plastics to be made in an environmentally-friendly and sustainable manner. The research was published in Nature Biotechnology.
biorefineries which transform non-edible biomass into fuel, heat, power, chemicals and materials have received a great deal of attention as a sustainable alternative to decreasing the reliance on fossil fuels. Renewable non-food biomass could potentially replace petrochemical raw materials to produce energy sources, useful chemicals, or a vast array of petroleum-based end products such as plastics, lubricants, paints, fertilizers and vitamin capsules. In the present study, a team headed by Distinguished Professor Lee Sang Yup of the Korea Advanced Institute of Science and Technology (KAIST) adopted a systems metabolic engineering approach to develop a microorganism that can produce various non-natural polymers which have biomedical applications. According to the researchers, this approach is the first successful example of biological production of poly(lactate-co-glycolate) (PLGA) and several novel copolymers from renewable biomass by one-step direct fermentation of metabolically engineered Escherichia coli (E. coli) bacteria. The researchers drew inspiration from the biosynthesis process for polyhydroxyalkanoates, biologically-derived polyesters produced in nature by the bacterial fermentation of sugar or lipid. From there, they designed a metabolic pathway for the biosynthesis of PLGA through microbial fermentation directly from carbohydrates in E. coli strains. PLGA is a biodegradable, biocompatible and non-toxic polymer. PLGA has been widely used in biomedical and therapeutic applications such as surgical sutures, prosthetic devices, drug delivery, and tissue engineering. In order to produce PLGA by microbial fermentation directly from carbohydrates, the team incorporated external and engineered enzymes as catalysts to co-polymerize PLGA while establishing a few additional metabolic pathways for the biosynthesis to produce a range of different non-natural polymers. This bio-based synthetic process for PLGA and other polymers could substitute for existing complicated chemical production methods. Lee and his team has also managed to produce a variety of PLGA copolymers with different monomer compositions such as the US Food and Drug Administration-approved monomers 3-hydroxyburate, 4-hydroxyburate, and 6-hydroxyhexanoate. Newly applied bioplastics such as 5-hydroxyvalerate and 2-hydroxyisovalerate were also made.http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.3485.html

Comment by Dr. Krishna Kumari Challa on March 24, 2016 at 9:59am

AI to Devise Unthinkable Experiments
Quantum mechanics predicts a number of, at first sight, counterintuitive phenomena. It therefore remains a question whether our intuition is the best way to find new experiments. Here, we report the development of the computer algorithm Melvin which is able to find new experimental implementations for the creation and manipulation of complex quantum states. Indeed, the discovered experiments extensively use unfamiliar and asymmetric techniques which are challenging to understand intuitively. The results range from the first implementation of a high-dimensional Greenberger-Horne-Zeilinger state, to a vast variety of experiments for asymmetrically entangled quantum states—a feature that can only exist when both the number of involved parties and dimensions is larger than 2. Additionally, new types of high-dimensional transformations are found that perform cyclic operations. Melvin autonomously learns from solutions for simpler systems, which significantly speeds up the discovery rate of more complex experiments. The ability to automate the design of a quantum experiment can be applied to many quantum systems and allows the physical realization of quantum states previously thought of only on paper.
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.090405

Comment by Dr. Krishna Kumari Challa on March 24, 2016 at 9:29am

Comment by Dr. Krishna Kumari Challa on March 24, 2016 at 9:22am

Scientists find ancient viral strands hiding in human DNA
"This is a thrilling discovery"
Researchers have discovered 19 unique fragments and stands of viral DNA in the genomes of modern humans.

Scientists analyzed the genomes of some 2,500 people from around the world. The viral fragments were identified by comparing the genomes to a "reference" human genome, an average of sorts. The comparative analysis allowed researchers to hone in on unique segments and locate foreign code.

Human endogenous retroviruses, or HERVs, are ancient viruses that succeeded in depositing DNA-based copies of their RNA genetic material into the genomes of early humans.
"Discovery of unfixed endogenous retrovirus insertions in diverse human populations"
http://www.pnas.org/content/early/2016/03/16/1602336113
The scientists say...this is because...

The human endogenous retrovirus (HERV) group HERV-K contains nearly intact and insertionally polymorphic integrations among humans, many of which code for viral proteins. Expression of such HERV-K proviruses occurs in tissues associated with cancers and autoimmune diseases, and in HIV-infected individuals, suggesting possible pathogenic effects. Proper characterization of these elements necessitates the discrimination of individual HERV-K loci; such studies are hampered by our incomplete catalog of HERV-K insertions, motivating the identification of additional HERV-K copies in humans. By examining >2,500 sequenced genomes, they have discovered 19 previously unidentified HERV-K insertions, including an intact provirus without apparent substitutions that would alter viral function, only the second such provirus described. Their results provide a basis for future studies of HERV evolution and implication for disease.

Comment by Dr. Krishna Kumari Challa on March 23, 2016 at 10:13am

Comment by Dr. Krishna Kumari Challa on March 23, 2016 at 9:46am

If you have a very small circle of friends and you are happy about it, then it might be a sign that you are intelligent as a new study has revealed that loners tend to be more intellectual than others.
The research is published in the British Journal of Psychology.

Comment by Dr. Krishna Kumari Challa on March 23, 2016 at 9:27am

Role of bacteria in platinum formation...
Australian scientists have uncovered the important role of specialist bacteria in the formation and movement of platinum and related metals in surface environments. Published in the journal Nature Geoscience, the research has important implications for the future exploration of platinum group metals.
These platinum group elements are strategically important metals, but finding new deposits is becoming increasingly difficult due to our limited understanding of the processes that affect the way they are cycled through surface environments.
This research reveals the key role of bacteria in these processes. This improved bio geochemical understanding is not only important from a scientific perspective but scientists hope will also lead to new and better ways of exploring for these metal.
Traditionally it was thought that these platinum group metals only formed under high pressure and temperature systems deep underground, and that when they were brought to the surface through weathering and uplift, they just sat there and nothing further happened to them.

Now scientists have shown that that is far from the case. They have linked specialised bacterial communities, found in biofilms on the grains of platinum group minerals at three separate locations around the world, with the dispersion and re-concentration of these elements in surface environments.

They've shown that nuggets of platinum and related metals can be reformed at the surface through bacterial processes.
Source: University of Adelaide

Comment by Dr. Krishna Kumari Challa on March 21, 2016 at 9:28am

A parallel realm of carbon-polluting activity - ranging from email exchanges to social network chatter (tweets, posts etc) to streaming movies on smartphones - has slipped largely unnoticed under the climate change radar. In isolation, these discrete units of our virtual existence seem weightless and without cost.
A short email, for example, is estimated to add about four grams of CO2-equivalent (CO2e) into the atmosphere.
By comparison, humanity emits some 40 billion tonnes of CO2 every year.
But as the digital era deepens, the accumulated volume of virtual messages has become a significant part of humanity's carbon footprint.
"Electricity consumption related to the growth of digital technologies is exploding," notes Alain Anglade of the French Environment and Energy Management Agency. In France it already accounts for more than 10% of total electricity use, he said, a percentage that holds for many developed countries. To see the big picture, it helps to break it down.
Sending five dozen of those four-gram emails in a day from your smartphone or laptop, for example, is the equivalent of driving an average-size car a kilometre. AFP

Comment by Dr. Krishna Kumari Challa on March 18, 2016 at 10:58am

Using flashes of blue light, scientists have pulled forgotten memories out of the foggy brains of mice engineered to have signs of early Alzheimer’s disease. This memory rehab feat, described online March 16 in Nature, offers new clues about how the brain handles memories, and how that process can go awry.
To recover a lost memory, scientists first had to mark it. Neuroscientist Susumu Tonegawa of MIT and colleagues devised a system that tagged the specific nerve cells that stored a memory — in this case, an association between a particular cage and a shock. A virus delivered a gene for a protein that allowed researchers to control this collection of memory-holding nerve cells. The genetic tweak caused these cells to fire off signals in response to blue laser light, letting Tonegawa and colleagues call up the memory with light delivered by an optic fiber implanted in the brain.

A day after receiving a shock in a particular cage, mice carrying two genes associated with Alzheimer’s seemed to have forgotten their ordeal; when put back in that cage, these mice didn’t seem as frightened as mice without the Alzheimer’s-related genes. But when the researchers used light to restore this frightening memory, it caused the mice to freeze in place in a different cage. (Freezing in a new venue showed that laser activation of the memory cells, and not environmental cues, caused the fear reaction.)

The fact that this memory could be pulled out with light helps clarify the source of memory trouble for people with Alzheimer’s. People in the early stages of the disease seem able to create new memories, but then rapidly forget them, he says. Memories can sometimes be strengthened with reminders and clues from the environment, suggesting that they are “somewhere in there,” but not retrievable.
Further experiments with the mice showed that the fear memory could be strengthened by forcing it to appear multiple times. This memory boot camp worked because it boosted the number of docking sites on memory-holding nerve cells in the mice with Alzheimer’s-related genes. Usually, these docking sites — knobs called dendritic spines that receive messages from other nerve cells — become scarcer with age. To counter that, Tonegawa and colleagues used light to repeatedly activate nerve cells that in turn activate the memory-holding cells. Compared with mice that didn’t get this strengthening treatment, mice with the Alzheimer’s genes that underwent this process were more fearful of the cage where they had received a shock, even six days later.
The results are only experimental but several insights have been gained on how memory works.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17172...

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