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Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:18am

When nose acts like brain...

Hormone ‘Erases’ Male Smell for Female Mice

In a new study, scientists at The Scripps Research Institute (TSRI) have found that state-specific odor “blindness” exists in female mice. Their research shows that female mice cannot sense the odor of male mice when they are in diestrus, the period of sexual inactivity during the reproductive cycle.

The researchers discovered that during this period, receptors in the female mouse’s nose actually block the signals from male odor molecules from ever reaching the brain. This lack of sensation directly affects mouse behavior.

“The nose was making decisions and acting like an extension of the brain.”

These findings, which point to new avenues for studying senses and behavior, were published June 4, 2015, in the journal Cell.

The new study started with an observation well-known in the field: While female mice are attracted to male mice during estrus—when they are receptive to breeding—female mice are indifferent to, and even aggressive toward, male mice during diestrus.

Researchers have long suspected that this change in behavior is related to hormonal changes in the brain during the reproductive cycle. Hormones produced in the ovaries during estrus and diestrus are known to activate specific neurons in the female brain. Stowers and her team aimed to study those neurons further. Before they investigated the brain, however, the researchers first wanted to rule out any activity in the nose that might be affecting the odor cues.

The researchers investigated a subset of neurons in a special organ in the nose called the vomeronasal organ (VNO), which detects male odors.

Using a technique called calcium imaging, the researchers discovered that these neurons don’t always detect male odors. The neurons have a “gating” mechanism and fail to activate in the presence of a hormone called progesterone, which is produced in the ovaries during diestrus. They found that progesterone acts through receptors on the surface of these sensory neurons, stopping them from transmitting the male odor smell to the brain.

Without these neurons activating, the female mouse can’t perceive male odors that promote behavior. This means ­the choice to perform behavior is being regulated in the nose itself, without thought from the brain.

What made the findings even stranger was the fact that no progesterone receptors had ever been detected in VNO neurons before. This prompted the researchers to dig further to figure out what was going on.

First, the researchers wanted to see if progesterone was disabling VNO function altogether.

To test this, the researchers checked the VNO response to predator cues—in this case, the scent of cat urine, which mice instinctually avoid. The researchers found that the subset of VNO neurons that usually respond to cat urine continued to respond normally, even in the presence of progesterone.

This showed that the ability female mice to smell in general was indeed still active during periods of diestrus.

Next, the researchers took a closer look at the signaling process. They discovered that when progesterone is detected by VNO neurons, it changes a signaling molecule that would normally relay the odor to the brain. Because only male odor-specific VNO neurons are susceptible to this change, they are the only ones that switch off in the presence of progesterone.

The reason for this male odor “blindness” is still unclear. Stowers said there is no evidence for the notion that male odors distract females from finding food or shelter. After all, female mice can smell male mice during estrus, and they still survive.

http://www.cell.com/cell/abstract/S0092-8674%2815%2900555-3

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 6:37am

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 6:13am

Comment by Dr. Krishna Kumari Challa on June 4, 2015 at 7:30am

What is Sleep? Flame Challenge 2015 Entry by Eric Galicia from Eric Galicia on Vimeo.

Comment by Dr. Krishna Kumari Challa on June 3, 2015 at 9:48am

Why Asian Students Excel At Maths And Science What explains the stellar performance of Asian students, even when they study in the US?
Students from five nations and territories in Asia have topped the latest global school rankings in science and math conducted by the OECD (Organization of Economic Co-operation and Development). The top five are Singapore, Hong Kong, South Korea, Japan and Taiwan (the last two tied in fourth place). The surprise is Vietnam, which follows in 12th place .
Only two other Asian countries are included in the rankings this year—Thailand (47th) and Indonesia (69th).
The rankings are based on the Program for International Student Assessment (PISA) taken by 15-year-olds around the world every three years. OECD suggests a correlation between quality basic education and economic development—the better educated a country’s people are, the faster the country develops economically.

http://www.asianscientist.com/2015/06/features/asian-students-excel...

Comment by Dr. Krishna Kumari Challa on June 3, 2015 at 9:13am

Bacteria may cause type 2 diabetes

Bacteria and viruses have an obvious role in causing infectious diseases, but microbes have also been identified as the surprising cause of other illnesses, including cervical cancer (Human papilloma virus) and stomach ulcers (H. pylori bacteria). A new study by University of Iowa microbiologists now suggests that bacteria may even be a cause of one of the most prevalent diseases of our time - Type 2 diabetes.

The research team led by Patrick Schlievert, PhD, professor and DEO of microbiology at the UI Carver College of Medicine, found that prolonged exposure to a toxin produced by Staphylococcus aureus (staph) bacteria causes rabbits to develop the hallmark symptoms of Type 2 diabetes, including insulin resistance, glucose intolerance, and systemic inflammation.

"We basically reproduced Type 2 diabetes in rabbits simply through chronic exposure to the staph superantigen," Schlievert says.

The UI findings suggest that therapies aimed at eliminating staph bacteria or neutralizing the superantigens might have potential for preventing or treating Type 2 diabetes.

Obesity is a known risk factors for developing Type 2 diabetes, but obesity also alters a person's microbiome - the ecosystem of bacteria that colonize our bodies and affect our health.

"What we are finding is that as people gain weight, they are increasingly likely to be colonized by staph bacteria - to have large numbers of these bacteria living on the surface of their skin," Schlievert says. "People who are colonized by staph bacteria are being chronically exposed to the superantigens the bacteria are producing."

Schlievert's research has previously shown that superantigens - toxins produced by all strains of staph bacteria - disrupt the immune system and are responsible for the deadly effects of various staph infections, such as toxic shock syndrome, sepsis, and endocarditis.

The team's latest study, published recently in the journal mBio, shows that superantigens interact with fat cells and the immune system to cause chronic systemic inflammation, and this inflammation leads to insulin resistance and other symptoms characteristic of Type 2 diabetes. In examining the levels of staph colonization on the skin of four patients with diabetes, Schlievert's team estimate that exposure to the bacterial superantigens for people who are heavily colonized by staph is proportional to the doses of superantigen that caused the rabbits to develop diabetes symptoms in the team's experiments.

"I think we have a way to intercede here and alter the course of diabetes," Schlievert says. "We are working on a vaccine against the superantigens and we believe that this type of vaccine could prevent the development of Type 2 diabetes."

The team also is investigating the use of a topical gel containing glycerol monolaurate, which kills staph bacteria on contact, as an approach to eliminate staph bacteria from human skin. They plan to test whether this approach will improve blood sugar levels in patients with pre diabetes.
http://mbio.asm.org/content/6/2/e02554-14.abstract

Comment by Dr. Krishna Kumari Challa on June 2, 2015 at 9:13am

Global Warming Spawns Hybrid Species

Animals have been interbreeding for millennia. Even modern humans are the product of genetic exchange with Neanderthals some 60,000 years ago.

But the rate at which species interbreed is accelerating because of climate change, researchers say. As habitats and animal ranges change and bleed into one another, species that never before would have encountered one another are now mating.

Warmer temperatures have allowed grizzly bears and polar bears to venture to habitats they don’t usually occupy and mate to form a hybrid: the pizzly or grolar bear.

Similar trends have been observed between golden-winged warblers and blue-winged warblers.

This issue is horrendously complex because of our ability to change the environment.
s rainbow trout meet and interbreed with dwindling cutthroat trout populations, the survival of cutthroat trout is at risk. Instead, a hybrid species is taking its place.

It’s a major cause of species extinction—lots of species are now disappearing because they are being genetically swamped by other, commoner ones. In some cases, hybridization can lead to reduced genetic diversity in animals. Rather than growing a new branch on the [genetic] tree, you have two branches growing together. In the case of cutthroat-rainbow trout hybrids, the hybrids are less genetically fit, with offspring of the hybrids struggling to survive, a study led by researchers from the U.S. Geological Survey found.

The rate at which humans are driving species to extinction is 1,000 times faster than the rate at which animals would go extinct naturally.
"ADAPTATION:
The grolar bear dilemma -- do warming-created hybrids hurt species? "
http://www.eenews.net/stories/1060019399

Comment by Dr. Krishna Kumari Challa on May 31, 2015 at 8:18am

Comment by Dr. Krishna Kumari Challa on May 31, 2015 at 7:30am

How Bacteria Talk and how we can use this knowledge to control diseases

Comment by Dr. Krishna Kumari Challa on May 30, 2015 at 7:30am

Vials of bioterror bacteria have gone missing. Lab mice infected with deadly viruses have escaped, and wild rodents have been found making nests with research waste. Cattle infected in a university's vaccine experiments were repeatedly sent to slaughter and their meat sold for human consumption. Gear meant to protect lab workers from lethal viruses such as Ebola and bird flu has failed, repeatedly.

A USA TODAY Network investigation reveals that hundreds of lab mistakes, safety violations and near-miss incidents have occurred in biological laboratories coast to coast in recent years, putting scientists, their colleagues and sometimes even the public at risk.

Oversight of biological research labs is fragmented, often secretive and largely self-policing, the investigation found. And even when research facilities commit the most egregious safety or security breaches — as more than 100 labs have — federal regulators keep their names secret.

Of particular concern are mishaps occurring at institutions working with the world's most dangerous pathogens in biosafety level 3 and 4 labs — the two highest levels of containment that have proliferated since the 9/11 terror attacks in 2001. Yet there is no publicly available list of these labs, and the scope of their research and safety records are largely unknown to most state health departments charged with responding to disease outbreaks. Even the federal government doesn't know where they all are, the Government Accountability Office has warned for years.
http://www.usatoday.com/longform/news/2015/05/28/biolabs-pathogens-...

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