Research

Mind-Control Parasite Kills Mice’s Fear of Cats Permanently

An infection with a weakened form of the protozoan caused mice to permanently lose their innate fear of catsA fair amount of research has taken place on Toxoplasma gondii, the bizarre parasite that makes mice unafraid of cats, and the latest chapter is a strange one.

 

A new study shows that even a brief infection with a weakened form of the protozoan caused mice to permanently lose their innate fear of cats.

The protozoan is known to cause this change in mice after a lingering infection and after it produces cysts in the mouse brain, according to the study, published online Sept. 18 in the journal PLOS ONE. But until now scientists didn’t know this apparently long-lasting change could occur after only a short infection, and without development of cysts and brain inflammation. The study also showed the change occurred with weakened forms of all three major variants of the protozoa found in North America.

“It is remarkable that even after the infection has been largely or completely cleared, a profound behavioral change persists,” said Wendy Ingram, a study author and researcher at the University of California, Berkeley, in a statement from PLOS ONE. “Simply having a transient infection resulting in what is potentially a permanent change in host biology may have huge implications for infectious disease medicine.”

Ingram isn’t sure the mechanism involved in the long-term behavior change, though she speculates the parasite may disrupt the smell region of a mouse’s brain, preventing the rodent from detecting cat odor that would trigger the fear. Another possibility is that the parasite directly modifies mouse brain cells that are linked to memory and learning.

Toxoplasma gondii is found throughout the world and infects a large number of mammals, including humans. However, the protozoan can only reproduce within the bodies of cats, and in mice, the mind-controlling parasite has evidently evolved to make mice unafraid of felines and even, according to some research, sexually attracted to the odor of cat urine; this makes it more likely infected mice will be eaten, and the parasite will make it back into a cat to spawn.

The parasite is found in as many as one-third to one-half of humans, and its presence in the brain has been linked with suicide attempts. It may affect other areas of mental health: One study suggested that people with the parasite scored higher on tests of neuroticism, an emotional or mental trait characterized by high levels of anxiety or insecurity.

Resarchers had the volunteers chew gum, drink a bottle of water, cough or read a section of an article. The participants spent about 40 seconds on each activity.

“Our mouth is an opening into our health — our drinking and eating behaviors shed light on our diet,” said researcher Hao-hua Chu, a computer scientist at National Taiwan University in Taipei. “How frequently we cough also tells us about our health, and how frequently we talk is related to social activity that can be related to health.”

Each of these activities moves teeth in a unique way. When it came to recognizing what a study participant was doing based solely on data from the devices, the system researchers developed was up to 93.8 percent accurate

Source: Live Science.com

Ear Wax From Whales Keeps Record Of Ocean Contaminants

How often do whales clean their ears? Well, never. And so, year after year, their ear wax builds up, layer upon layer. According to a study published Monday, these columns of ear wax contain a record of chemical pollution in the oceans.

The study used the ear wax extracted from the carcass of a blue whale that washed ashore on a California beach back in 2007. Scientists at the Santa Barbara Museum of Natural History collected the wax from inside the skull of the dead whale and preserved it. The column of wax was almost a foot long.

“It’s kind of got that icky look to it,” says, an environmental scientist at Baylor University who was involved in the study. “It looks kind of like a candle that’s been roughed up a bit. It looks waxy and has got fibers. But it’s pretty rigid — a lot stronger and a lot more stable than one would think.”

There are light and dark layers within the column, each layer corresponding to six months of the whale’s life, Usenko says. Historically the rings have been used to estimate the age of the whale, he says, “very similar to counting tree rings.”

But age is not what Usenko was after. He studies how chemical pollutants like DDT and flame retardants are affecting whales. These pollutants get deposited in fatty tissues, such as whale blubber. And scientists often analyze blubber to see what whales are eating.

But analyzing blubber has a limitation, Usenko says.

“I would only know that organism — that [particular] animal was exposed to those contaminants,” he says. “I wouldn’t know when.”

And so he thought, why not look at ear wax, which is also a fatty material that accumulates toxic chemicals.

Because each layer of wax corresponds to six months of a whale’s life, by working through a plug of wax, Usenko could figure out when the animal was exposed to a particular chemical.

In this case, Usenko and his colleagues found that the whale had been exposed to worrisome pollutants throughout its lifetime.

He says the high levels of DDT surprised him.

“It’s been 30-plus years since we’ve stopped using this compound,” he says, “but to still see it showing up at such high concentrations — one of the dominant chemicals we see — was surprising.”

Usenko and his team also determined that “a significant percentage of the exposure occurred in the first, early stages of the animal’s life,” when it was still nursing, and perhaps especially vulnerable. At that point, the pollutants came from the mother, through her milk, the scientist says.

Usenko says he can’t tell just from looking at the wax whether these chemicals are hurting the development of young blue whales. He studied only one animal, and the ear wax alone can’t reveal whether the chemicals caused harm.

But the ear wax also contained a record of fluctuations in stress hormones throughout the animal’s life. And that, in combination with the chemical pollution data, may in the future provide better insight into the potential impacts of these chemicals on whales, Usenko says.

His appear in the latest issue of the Proceedings of the National Academy of Sciences.

But he needs more data, he says, so he has requested that scientists start collecting ear wax from dead beached whales the world over and mail the samples to him.

Source: npr news

New biomarker for diabetes risk identified

Researchers have identified a biomarker, which can help predict diabetes risk up to 10 years before its onset.

Thomas J. Wang, M.D., director of the Division of Cardiology at Vanderbilt, along with colleagues at Massachusetts General Hospital, conducted a study of 188 individuals who developed type 2 diabetes mellitus and 188 individuals without diabetes who were followed for 12 years as participants in the Framingham Heart Study.

Wang said that from the baseline blood samples, that they identified a novel biomarker, 2-aminoadipic acid (2-AAA), that was higher in people who went on to develop diabetes than in those who did not.

Individuals having 2-AAA concentrations in the top quartile had up to a fourfold risk of developing diabetes during the 12-year follow-up period compared with people in the lowest quartile.

Wang asserted that the caveat with these new biomarkers is that they require further evaluation in other populations and further work to determine how this information might be used clinically.

The researchers also conducted laboratory studies to understand why this biomarker is elevated so well in advance of the onset of diabetes.

They found that giving 2-AAA to mice alters the way they metabolize glucose. These molecules seem to influence the function of the pancreas, which is responsible for making insulin, the hormone that tells the body to take up blood sugar.

The findings have been published in The Journal of Clinical Investigation.

 

Nanodiamonds boost treatment of chemo-resistant leukemia

By binding multiple molecules of a common leukemia drug with nanodiamonds, scientists have managed to boost the delivery of the drug to leukemic cells and retain the drug within the cells to combat the cancer.

This novel discovery, reported for the first time, addresses one of the major challenges in the treatment of leukemia where the cancer cells develop ways to pump drugs out of the body before they can do their job, particularly after they are exposed to chemotherapeutics.

Developed by Dr Edward Chow, Principal Investigator at the Cancer Science Institute of Singapore and Assistant Professor at the Department of Pharmacology, Yong Loo Lin School of Medicine at National University of Singapore (NUS), in collaboration with Professor Dean Ho of the UCLA School of Dentistry, this innovation shows promise for greater efficacy in treating leukemia, particularly in non-adherent cells.

Daunorubicin is currently one of the most common drugs used to treat leukemia. The drug works by slowing down or stopping cancer cells from growing, causing many of them to die. It is also common, however, for leukemia to become resistant to this drug after treatment.

One mechanism by which this opposition, commonly known as chemoresistance, happens is through the expression of drug transporter pumps in leukemia cells that actively pump out chemotherapeutics, including Daunorubicin.

Current approaches to neutralising chemo-resistance have centred on developing competitive inhibitors. These efforts have limited success, with challenges like high toxicity levels and less-than-promising results during clinical trials.

The team of scientists from NUS and UCLA turned to nanodiamonds, which are tiny, carbon-based particles that are 2 to 8 nanometers in diameter, as an option to address chemo-resistance.

Dr Chow studied the biological basis of how nanodiamonds can potentially overcome chemo-resistance.

The scientists bound the surfaces of nanodiamonds with Daunorubicin, and the hybrid nanodiamond-drug complexes were introduced to leukemic cells.

The research team found that nanodiamonds could carry the drug to the cancer cells without being pumped out.

Due to their non-invasive sizes and unique surface features, nanodiamonds can be easily released without blocking up blood vessels.

The findings are published online in the medical journal Nanomedicine: Nanotechnology, Biology, and Medicine.

Source: Zee News

The final nail in the Jurassic Park coffin

It is hardly possible to talk about fossil insects in amber without the 1993 movie Jurassic Park entering the debate. The idea of recreating dinosaurs by extracting DNA from insects in amber has held the fascination of the public for two decades. Claims for successful extraction of DNA from ambers up to 130 million-years-old by various scientists in the early 1990s were only seriously questioned when a study at the Natural History Museum, London, was unable to replicate the process. The original claims are now considered by many to be a text-book example of modern contaminant DNA in the samples. Nonetheless, some scientists hold fast to their original claims.

Research just published in the journal The Public Library of Science ONE (PLOS ONE) by a team of researchers from the Faculty of Life Sciences at The University of Manchester can now confirm that the existence of DNA in amber fossils is highly unlikely. The team led by amber expert Dr David Penney and co-ordinated by ancient DNA expert Professor Terry Brown used highly-sensitive ‘next generation’ sequencing techniques – the most advance type of DNA sequencing – on insects in copal, the sub-fossilized resin precursor of amber.

The research was conducted wearing full forensic suits in the dedicated ancient DNA facility at The University of Manchester, which comprises a suite of independent, physically isolated laboratories, each with an ultra-filtered air supply maintaining positive displacement pressure and a managed access system.

According to Professor Brown: “In the original 1990s studies DNA amplification was achieved by a process called the polymerase chain reaction (PCR), which will preferentially amplify any modern, undamaged DNA molecules that contaminate an extract of partially degraded ancient ones to give false positive results that might be mistaken for genuine ancient DNA. Our approach, using ‘next generation’ sequencing methods is ideal for ancient DNA because it provides sequences for all the DNA molecules in an extract, regardless of their length, and is less likely to give preference to contaminating modern molecules.”

The team concluded that their inability to detect ancient DNA in relatively young (60 years to 10,600 years old) sub-fossilized insects in copal, despite using sensitive next generation methods, suggests that the potential for DNA survival in resin inclusions is no better, and perhaps worse, than that in air-dried museum insects (from which DNA has been retrieved using similar techniques). This raises significant doubts about claims of DNA extraction from fossil insects in amber, many millions of years older than copal.

Dr Penney said: “Intuitively, one might imagine that the complete and rapid engulfment in resin, resulting in almost instantaneous demise, might promote the preservation of DNA in a resin entombed insect, but this appears not to be the case. So, unfortunately, the Jurassic Park scenario must remain in the realms of fiction.”

Source: BBC News

Lefty or righty? Genes for handedness found

Genes that play a role in the orientation of internal organs may also affect whether someone is right- or left-handed, new research suggests.

The study, published Friday in the journal PLOS Genetics, suggests those genes may also play a role in the brain, thereby affecting people’s handedness.

Still, the findings can’t yet explain the mystery of why a minority of people are left-handed because each gene plays only a tiny role in people’s handedness.

“Handedness is a complex trait, there are hundreds of genes involved,” said study co-author William Brandler, a genetics doctoral candidate at the University of Oxford in England. “There are also lots of environmental influences.”

Origins of handedness

Throughout the world, between about 5 and 20 percent of the population is left-handed. Favoring one hand for most tasks can allow people to do things more quickly, but exactly why there’s such a strong bias toward right-handedness in humans is a mystery. Humans’ close relatives, such as chimpanzees, are equally likely to be southpaws.

A 2012 study suggested that more cooperative societies that share tools and tasks have more people with the same dominant hand. Other studies propose that being a leftie is handy in a fistfight — but only if most people are expecting a right hook.

Although a few genes have been implicated in handedness, genes are not the entire story, as identical twins often favor different hands. Some have even proposed that brain damage in utero causes brains to rewire to make people lefties.

Genetic links

To get at the genetic roots of handedness, Brandler (who is a southpaw) and his colleagues asked 728 people to move a row of 10 pegs using first their right hand, then their left. People who take much longer on one side versus the other have greater hand dominance.

The researchers then analyzed the genes of these people and identified several genes associated with greater hand dominance. They then confirmed the association in a larger group of 2,666 people.

The strongest association was with a gene called PCSK6 that creates left- and right- parts in utero. The other genes played a role in how the organs in the body are oriented.

People with defects in these genes may be otherwise healthy, but have situs inversus, a condition in which internal organs are mirrored from their normal orientation. Others have more serious defects, such as left-handed isomerism, in which people have essentially two left sides and multiple spleens throughout the body, or heterotaxia, a typically fatal condition where “organs are all over the place,” Brandler told Live Science.

The findings suggest that the same genes that affect the left-hand symmetry of organs in the body also affect the way the brain is wired. That, in turn, affects whether someone’s right or left hand is dominant.

“Handedness is an outward reflection of brain asymmetries for motor coordination,” Brandler said. “If you’re right-handed, it means you’re left hemisphere dominant for motor coordination. That’s because our brains are cross-wired.”

Still, to truly tease out the roots of left-handedness, researchers will need to untangle the role of hundreds of other genes and isolate environmental factors, he said.

Lobsters may be the answer to immortality

Scientists say they may have found the key to eternal life in an unexpected creature – lobsters.

Research shows the crustaceans possess an enzyme called telomerase, which makes them ‘biologically immortal.’ Growing older doesn’t raise their chance of death, The Sun reported.

In other living creatures, strands of DNA get shorter as cells replicate and die, and they eventually become too badly damaged to copy new cells.

But in lobsters, telomerase prevents DNA strands from shortening, allowing perfect cells to replicate again and again, according to biologist Simon Watts, founder of ReadySteadyScience.com.

The average lobster weighs under 2 pounds, but near the coast of Maine in 2009, fishermen caught a lobster that weighed 19 pounds, meaning the creature was approximately 140 years old.

Medical experts hope further studies about telomerase will help discover new ways to increase lifespan and prevent cancer.
Source: Fox news

 

Autoimmune diseases may soon become history

An immunologist has said that with some prompting, the protein STING can turn down the immune response or even block its attack on healthy body constituents like collagen, insulin and the protective covering of neurons – targets of the debilitating diseases.

Medical College of Georgia researchers saw STING’s critical role play out after they injected into the bloodstream submicroscopic DNA nanoparticles, engineered carriers for delivering drugs or genes into cells.

They learned that the magic is in STING, which recognizes the molecule that senses the DNA then prompts release of IDO, or indoleomine 2,3-dioxyegenase.

Dr. Andrew L. Mellor, immunologist at the Medical College of Georgia at Georgia Regents University said that the fact that STING is actually part of the DNA-sensing pathway tells us something we did not know before.

DNA nanoparticles apparently look to the body a lot like the debris that results when dying cells release DNA from their nucleus.

Researchers already knew there was a link between STING and immunity: the food-borne bacterium listeria releases cyclic dinucleotides to activate STING in cells it has infected.

When MCG researchers put the STING stimulus into the bloodstream, it results in suppression. Other scientists have generated the exact opposite effect by injecting STING stimulating reagents under the skin.

In the bloodstream, there are a lot of immune cells called phagocytes that ingest the submicroscopic particles that wind up in the fluid portion of the cell, called the cytoplasm, where most cellular activity happens.

There, sensors detect the DNA and trigger signaling that leads to expression of IDO. In this complex interplay, STING appears essential to recognizing the molecule that recognizes the DNA.

The study has been published in the Journal of Immunology.

Copper can destroy highly infectious norovirus

      Copper and copper alloys can rapidly           destroy norovirus – the highly-                       infectious sickness bug, scientists have       discovered.

Worldwide, norovirus is responsible             for more than 267 million cases of                 acute gastroenteritis every year,                     researchers said.

The virus, for which there is no specific treatment or vaccine, can be contracted from contaminated food or water, person-to-person contact, and contact with contaminated surfaces, meaning surfaces made from copper could effectively shut down one avenue of infection.

The study, which was designed to simulate fingertip-touch contamination of surfaces, showed norovirus was rapidly destroyed on copper and its alloys, with those containing more than 60 per cent copper proving particularly effective.

Copper alloys have previously been shown to be effective antimicrobial surfaces against a range of bacteria and fungi.

The research reported rapid inactivation of murine norovirus on alloys, containing over 60 per cent copper, at room temperature but no reduction of infectivity on stainless steel dry surfaces in simulated wet fomite and dry touch contamination.

The rate of inactivation was initially very rapid and proportional to the copper content of alloy tested. Viral inactivation was not as rapid on brass as previously observed for bacteria but copper-nickel alloy was very effective.

One of the targets of copper toxicity was the viral genome and a reduced number of the gene for a viral encoded protein, VPg (viral-protein-genome-linked), which is essential for infectivity, was observed following contact with copper and brass dry surfaces.

“The use of antimicrobial surfaces containing copper in clinical and community environments, such as cruise ships and care facilities, could help to reduce the spread of this highly infectious and costly pathogen,” lead author Sarah Warnes, from the Centre for Biological Sciences at the University of Southampton, said.

“Copper alloys, although they provide a constant killing surface, should always be used in conjunction with regular and efficient cleaning and decontamination regimes using non-chelating reagents that could inhibit the copper ion activity,” said Warnes.

“Although the virus was identified over 40 years ago, the lack of methods to assess infectivity has hampered the study of the human pathogen,” Co-author Professor Bill Keevil, from the University`s Institute for Life Sciences, added.

“The virus can remain infectious on solid surfaces and is also resistant to many cleaning solutions. That means it can spread to people who touch these surfaces, causing further infections and maintaining the cycle of infection. Copper surfaces, like door handles and taps, can disrupt the cycle and lower the risk of outbreaks,” Keevil said.

The study was published in the journal PLOS ONE.

Cell transplants could help treat schizophrenia

Researchers have suggested that the cell transplants could be used to treat schizophrenia.

Senior author Daniel Lodge, Ph.D., assistant professor of pharmacology in the School of Medicine at the University of Texas Health Science Center at San Antonio, said that since these cells are not functioning properly, our idea is to replace them.

Lodge and lead author Stephanie Perez, graduate student in his laboratory, biopsied tissue from rat fetuses, isolated cells from the tissue and injected the cells into a brain center called the hippocampus.

This center regulates the dopamine system and plays a role in learning, memory and executive functions such as decision making. Rats treated with the transplanted cells have restored hippocampal and dopamine function.

Lodge said that they put in a lot of cells and not all survived, but a significant portion did and restored hippocampal and dopamine function back to normal.

The study has been published in Molecular Psychiatry.