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Comment by Dr. Krishna Kumari Challa on March 3, 2016 at 8:27am

Scientists telling politicians in the US why science is important...

Comment by Dr. Krishna Kumari Challa on February 26, 2016 at 7:29am

Bad DNA can flout rules of inheritance :

R2d2 can quickly spread to an entire mouse population despite its evolutionary disadvantage

In living animals, a selfish bit of DNA called R2d2 is an outright lawbreaker. It violates laws of both genetic inheritance and Darwinian evolution. R2d2 can sweep through mouse populations by mimicking helpful mutations while actually damaging fertility, researchers report online February 15 inMolecular Biology and Evolution.

The new findings suggest that even genes that hurt an organism’s evolutionary chances can cheat their way to the top. That could be good news for researchers hoping to use engineered “gene drives” to eliminate mosquito-borne diseases and invasive species. But it’s also a cautionary tale for scientists looking for signs that natural selection has picked certain genes because they offer an evolutionary benefit.

If researchers aren’t careful, they may be hoodwinked into thinking that a selfish gene is one that has some evolutionary advantage. The genetic signatures are the same. But what looks like survival of the fittest may actually be a cheater prospering. The selfish DNA could blaze through populations. The proportion of mice with the selfish gene more than tripled in one laboratory population from 18 percent to 62 percent within 13 generations, the researchers found. In another breeding population, R2d2 shot from being in 50 percent of the lab mice to 85 percent in 10 generations. By 15 generations, the selfish element reached “fixation” — all the mice in the population carried it.

Such wildfire spread of a gene variant that eventually wipes out all other versions is known as a selective sweep. Sweeps are hallmarks of a gene that helps an organism adapt to its environment. But this study suggests that what looks like adaptation may actually be selfish genetics at work.

R2d2 is a “selfish element,” a gene or other piece of DNA that causes itself to be inherited preferentially.

The droid’s namesake is a stretch of DNA on mouse chromosome 2 that contains multiple copies of the Cwc22 gene. When seven or more copies of that gene build up on the chromosome, R2d2 gets selfish. In female mice, it elbows aside the chromosome that doesn’t contain the selfish version of the gene and is preferentially incorporated into eggs. That’s a violation of the laws of inheritance spelled out by Gregor Mendel in which each gene or chromosome is supposed to have a fifty-fifty chance of being passed on to the next generation. But there is a cost to R2d2’s selfishness: Female mice that carry one copy of the selfish element have small litter sizes compared with mice that don’t carry the greedy DNA.

Under evolutionary laws, that loss of fertility should cause natural selection to weed outR2d2. But the selfish element’s greed is greater than the power of natural selection to combat it, the lab experiments show.

 The relatively low proportion of wild mice carrying R2d2 could mean that some mice have developed ways to suppress the gene’s selfishness.

- Sciencenews.org

Comment by Dr. Krishna Kumari Challa on February 24, 2016 at 8:50am

If you are highly goal oriented, your perception of the world changes to suit you! That is what  Dr. Jessica Witt of Colorado State University explained - how well you're performing affects your visual perception of the world around you, at the annual meeting of the American Association for the Advancement of Science .

  According to her the ball actually looks bigger to higher hitters in baseball and the hole looks bigger to good golfers!! To see if athletes performing better really do perceive their environment differently, she went to softball games.

In her experiments with sports persons, she found that people who hit better selected a larger circle fromt eh circle she showed them, meaning the batters who were hitting better saw the ball as bigger. Which means not everyone sees the ball the same way. And it also means that what we see is affected by our ability to act. Performance impacts vision.

In other studies she found that golfers who putted better saw the hole as bigger than did poor putters. Faster swimmers saw targets underwater as being closer than did slower swimmers. And she had athletes who were not placekickers try to make field goals. The ones who did better saw the space between the uprights as wider. Bottom line:

“You don’t see the world the same as each other. You see the world in a way that’s unique to you, and it’s unique to your abilities.”

 ----

when traveling abroad, people often find local residents’ body odor particularly offensive. And mothers tend to believe that other infants smell far less appealing than their own. Now, in a study published this week in Proceedings of the National Academy of Sciences, a group of researchers has shown that the degree of disgust people find in others’ sweat may vary with group identification. In other words, disgust may depend on whether one considers the person they smell to be a member of their “in-group” or “out-group.”

Comment by Dr. Krishna Kumari Challa on February 23, 2016 at 7:54am

Comment by Dr. Krishna Kumari Challa on February 19, 2016 at 6:51am

Sex difference in pathology of the ageing gut mediates the greater response of female lifespan to dietary restriction
Women live on average longer than men, but have greater levels of late-life morbidity. Scientists have uncovered a substantial sex difference in the pathology of the ageing gut in Drosophila. The intestinal epithelium of the ageing female undergoes major deterioration, driven by intestinal stem cell (ISC) division, while lower ISC activity in males associates with delay or absence of pathology, and better barrier function, even at old ages. Males succumb to intestinal challenges to which females are resistant, associated with fewer proliferating ISCs, suggesting a trade-off between highly active repair mechanisms and late-life pathology in females. Dietary restriction reduces gut pathology in ageing females, and extends female lifespan more than male. By genetic sex reversal of a specific gut region, we induced female-like ageing pathologies in males, associated with decreased lifespan, but also with a greater increase in longevity in response to dietary restriction.
http://elifesciences.org/content/5/e10956v1?utm_source=content_aler...

Comment by Dr. Krishna Kumari Challa on February 18, 2016 at 8:52am

The reason for hair loss identified
Hair follicle aging is driven by transepidermal elimination of stem cells...
Japanese researchers have identified that DNA damage to stem cells in the hair follicles turns them into skin cells which subsequently leave the scalp. These findings, published in Science, could potentially lead to new treatments for hair loss and other aging-associated diseases. The hair follicle is an epithelial mini-organ of the skin. As it ages, it naturally shrinks or miniaturizes, and its functions and regenerative ability decline. Hair follicles contain hair follicle stem cells (HFSCs) that activate in cyclical growth phases; the longer the growth phase, the longer the hair. While aging in organisms has been explained by various theories, not much is known about the role of stem cells in the organ aging process. Studying hair follicles as mini-organs, Professor Emi K. Nishimura and colleagues from the Department of Stem Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, set out to investigate the impact of aging on HFSCs, and if there was any link to aging-associated hair loss. In a study of wild-type mice models, they found that HFSCs accumulate DNA damage as they renew during repetitive hair cycles, leading to a breakdown of type XVII collagen (COL17A1) which is crucial for the maintenance of HFSCs. Once these aged HFSCs are activated during the hair cycle, they eventually leave the follicle, turn into epidermal keratinocytes and are then eliminated from the skin surface. Then, to see if this was the same for humans as well, the team analyzed healthy human scalp skin from women at ages ranging from 22 to 70 years old. They found that human female scalps from the aged group (55 to 70 years old) contain significantly more miniaturized hair follicles compared with the younger group (35 to 45 years old). The team’s findings show that hair follicle aging is initially caused by DNA damage that accumulates in renewing HFSCs as they age. This thus leads to hair follicles in mammals miniaturizing and even disappearing from the skin, regardless of gender, in both mice and humans. It is worth noting that hair follicle aging is also linked to intrinsic genomic instability, as in the case of the genetic disorders such as progeria. Indeed, this dynamic hair follicle aging program is a good model of how different organs and tissue miniaturize and become less functional with age, the authors wrote.

http://science.sciencemag.org/content/351/6273/aad4395

Comment by Dr. Krishna Kumari Challa on February 16, 2016 at 7:55am

IRRI scientists' breakthrough may usher 'green revolution'
Rice-growing techniques learned through thousands of years of trial and error are about to be charged with DNA technology in a breakthrough hailed by scientists as a potential second "green revolution".
Over the next few years farmers are expected to have new genome sequencing technology at their disposal, helping to offset a myriad of problems that threaten to curtail production of the grain that feeds half of humanity.
Drawing on a massive bank of varieties stored in the Philippines and state-of-the-art Chinese technology, scientists recently completed the DNA sequencing of more than 3,000 of the world's most significant types of rice.
With the huge pool of data unlocked, rice breeders will soon be able to produce higher-yielding varieties much more quickly and under increasingly stressful conditions, scientists involved with the project said.
Since rice was first domesticated thousands of years ago, farmers have improved yields through various planting techniques.
For the past century breeders have isolated traits, such as high yields and disease resistance, then developed them through cross breeding.
However, they did not know which genes controlled which traits, leaving much of the effort to lengthy guesswork.
The latest breakthroughs in molecular genetics promise to fast-track the process, eliminating much of the mystery, according to scientists involved in the project.
Better rice varieties can now be expected to be developed and passed on to farmers' hands in less than three years, compared with 12 without the guidance of DNA sequencing.
Genome sequencing involves decoding DNA, the hereditary material of all living cells and organisms. The process roughly compares with solving a giant jigsaw puzzle made up of billions of microscopic pieces.
A multinational team undertook the four-year project with the DNA decoding primarily in China by BGI, the world's biggest genome sequencing firm.

Comment by Dr. Krishna Kumari Challa on February 15, 2016 at 6:36am

Meeting humanity’s increasing demand for freshwater and protecting ecosystems at the same time, thus maintaining blue water footprints within maximum sustainable levels per catchment, will be one of the most difficult and important challenges of this century

                                               *************

Air Pollution Kills Over 5.5 Million People Worldwide Annually

More than 5.5 million people worldwide die prematurely every year due to household and outdoor air pollution, and India and China together account for 55 per cent of these deaths, new research has found.

About 1.6 million people died of air pollution in China and 1.4 million died in India in 2013, the researchers said.

The international team of researchers from India, China, Canada and the US estimated that despite efforts to limit future emissions, the number of premature deaths linked to air pollution will climb over the next two decades unless more aggressive targets are set.

The findings were presented on Friday at the 2016 annual meeting of the American Association for the Advancement of Science (AAAS) in Washington, DC.

Power plants, industrial manufacturing, vehicle exhaust and burning coal and wood all release small particles into the air that are dangerous to a person's health.

In India, a major contributor to poor air quality is the practice of burning wood, dung and similar sources of biomass for cooking and heating.

Millions of families, among the poorest in India, are regularly exposed to high levels of particulate matter in their own homes.

India needs a three-pronged mitigation approach to address industrial coal burning, open burning for agriculture, and household air pollution sources.

The study highlights the urgent need for even more aggressive strategies to reduce emissions from coal and from other sectors.

Comment by Dr. Krishna Kumari Challa on February 13, 2016 at 8:25am

Honda Motor India has announced the ninth Young Engineers and Scientists’ (Y-E-S) awards for 2015 in India. The Young Engineers and Scientists’ Award were presented to 14 students from India’s premier institutes for science and technology – the Indian Institute of Technology. The Y-E-S awards were instituted by Honda Foundation in India in 2008 to encourage and support young Indian engineers and scientists.

Comment by Dr. Krishna Kumari Challa on February 13, 2016 at 8:22am

Reducing drug experiments with human beings with the help of Robots...
Researchers, including an Indian-origin scientist, have created a robotically-driven experimentation system to determine the effects of a large number of drugs on many proteins, reducing the number of necessary experiments by as much as 70 percent.

"Biomedical scientists have invested a lot of effort in making it easier to perform numerous experiments quickly and cheaply," said lead author Armaghan Naik from Carnegie Mellon University's computational biology department.

"However, we simply cannot perform an experiment for every possible combination of biological conditions, such as genetic mutation and cell type. Researchers have, therefore, had to choose a few conditions or targets to test exhaustively, or pick experiments themselves. The question is which experiments do you pick," Naik added.

For this, Naik's team previously described the application of a machine learning approach called "active learning".

This involved a computer repeatedly choosing which experiments to do, in order to learn efficiently from the patterns it observed in the data.

While their approach had only been tested using synthetic or previously acquired data, the team's current model builds on this by letting the computer choose which experiments to do.

The experiments were then carried out using liquid-handling robots and an automated microscope. As the system progressively performed the experiments, it identified more phenotypes and more patterns in how sets of proteins were affected by sets of drugs.

The model was recently presented in the journal eLife.
http://elifesciences.org/content/5/e10047v1

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