Knowledge Update

​New York, March 25 (IANS) What has brain to do with glucose metabolism? A lot, say researchers, suggesting that not just your pancreas, a group of neurons in the hypothalamus area also plays a vital role in maintaining blood glucose levels.

The team from Rockefeller University and Rensselaer Polytechnic Institute have used magnetic forces to remotely control the flow of ions into specifically targeted cells in mice.

Jeffrey Friedman, head of the laboratory of molecular genetics, and colleagues successfully employed this system to study the role of the central nervous system in glucose metabolism.

“These results are exciting because they provide a broader view of how blood glucose is regulated -- they emphasize how crucial the brain is in this process," Friedman said.

“Having a new means for controlling neural activity, one that doesn't require an implant and allows you to elicit rapid responses, fills a useful niche between the methods that are already available,” added the scientist in a paper which appeared in the journal Nature.

The new study is the first to turn neurons on and off remotely with radio waves and magnetic fields.

Using this novel method, the researchers investigated the role these glucose sensing neurons play in blood glucose metabolism.

Hormones released by the pancreas, including insulin, maintain stable levels of glucose in the blood.

A region of the brain called the ventromedial hypothalamus was thought to play a role in regulating blood glucose.

Friedman and colleagues found that when they switched these neurons on with magnetic forces, blood glucose increased, insulin levels decreased, and behaviourally, the mice ate more.

When they inhibited the neurons, on the other hand, the opposite occurred, and blood glucose decreased.

“We tend to think about blood glucose being under the control of the pancreas, so it was surprising that the brain can affect blood glucose in either direction to the extent that it can," Friedman noted.

The system has several advantages that make it ideal for studies on other circuits in the brain or elsewhere.

It can be applied to any circuit, including dispersed cells like those involved in the immune system.

In addition to its utility as a research tool, the technique may also have clinical applications.

“Depending on the type of cell we target and the activity we enhance or decrease within that cell, this approach holds potential in development therapies for metabolic and neurologic diseases,” explained Jonathan Dordick from Rensselaer.​

New York, March 25 (IANS) Do you love Swiss chocolates more than those from Indonesia? You may thank diverse yeast population for that particular taste as researchers have found that those differences may play an important role in the characteristics of chocolate and coffee from different parts of the world.

In comparison to the yeasts found in vineyards around the world, those associated with coffee and cacao beans show much greater diversity, the findings showed.

"Our study suggests a complex interplay between human activity and microbes involved in the production of coffee and chocolate," said Aimee Dudley of the Pacific Northwest Diabetes Research Institute in Seattle, US. 

"Humans have transported and cultivated the plants, but at least for one important species, their associated microbes have arisen from transport and mingling in events that are independent of the transport of the plants themselves," Dudley noted.

Coffee and cacao trees originally grew in Ethiopia and the Amazon rain forest. They are now widely cultivated across the "bean belt" that surrounds the equator. 

After they are picked, both cacao and coffee beans are fermented for a period of days to break down the surrounding pulp. 

This microbe-driven process also has an important influence on the character and flavour of the beans.

To explore further, the researchers bought unroasted coffee and cacao beans grown in Central and South America, Africa, Indonesia or the Middle East and isolated the associated yeast in their Seattle laboratory. 

Genetic analysis of those yeast strains revealed that yeasts from coffee and cacao beans were substantially more diverse than the wine yeasts. 

Interestingly, the genetic signatures of the yeast strains strongly clustered according to the geographic origin of the beans, the study said.

In fact, this association was so strong that they were able to accurately determine the origin of the beans solely from the DNA sequences of their associated yeasts, Dudley said.

The findings appeared in the journal Current Biology.

The findings showed that the yeast strains associated with coffee and cacao have multiple, independent origins. 

The researchers believe that the findings could lead to improvements in chocolate and coffee. ​

​London, March 22 (IANS) The time and date of birth determines our horoscope and the characteristics associated with it. However, a new study reveals a specific marker in our genes, which gives us the horoscope by the seasons of birth and shows how it influences so many things in our life.

The study showed that the season a person is born in influences a wide range of things: From risk of allergic disease, to height and lifespan. 

But, relatively little is known about how a one-time exposure, such as the season of birth, could hold lasting effects.

A specific marker that has been discovered on human deoxyribonucleic acid (DNA) has been instrumental in linking the season of birth to risk of allergy in later life.

“It might sound like a horoscope by the seasons, but now we have scientific evidence for how that horoscope could work. Because season of birth influences so many things, the epigenetic marks discovered in this study could also potentially be the mechanism for other seasonally influenced diseases and traits too, not just allergy,” said lead author Gabrielle Lockett from University of Southampton in Britain.

The findings, published in the journal Allergy, revealed that particular epigenetic marks (specifically, DNA methylation) were associated with season of birth and still present 18 years later. 

Also, this epigenetic marks exposed the link to allergic disease, for example people born in autumn had an increased risk of eczema compared to those born in spring.

“Epigenetic marks are attached onto DNA, and can influence gene expression (the process by which specific genes are activated to produce a required protein) for years, maybe even into the next generation,” explained one of the researchers John Holloway, professor at Southampton University.

While these results have clinical implications in mediating against allergy risk, we are not advising altering pregnancy timing,” Holloway added.

The team conducted epigenetic scanning on DNA samples from a group of people born on the Isle of Wight in Britain and the results were validated in a cohort of Dutch children.​

A new technique developed by a team of chemists at Stanford University has shown promise to be thousands of times more sensitive than current techniques to diagnose diseases -- whether it is a cancer or a virus like HIV.

Found effective in laboratory experiments, the technique, described in the journal ACS Central Science, is now being put to test in real-world clinical trials.

When a disease begins growing in the body, the immune system responds by producing antibodies.

Fishing these antibodies or related biomarkers out of the blood is one way that scientists infer the presence of a disease.

This involves designing a molecule that the biomarker will bind to, and which is adorned with an identifying "flag." Through a series of specialized chemical reactions, known as an immunoassay, researchers can isolate that flag, and the biomarker bound to it, to provide a proxy measurement of the disease.

The new technique, developed in the lab of Carolyn Bertozzi, professor of chemistry at Stanford, augments this standard procedure with powerful DNA screening technology.

In this case, the chemists replaced the standard flag with a short strand of DNA, which can then be teased out of the sample using DNA isolation technologies that are far more sensitive than those possible for traditional antibody detections.

The researchers tested their technique, with its signature DNA flag, against four commercially available tests for a biomarker for thyroid cancer.

It outperformed the sensitivity of all of them, by at least 800 times, and as much as 10,000 times.

By detecting the biomarkers of disease at lower concentrations, physicians could theoretically catch diseases far earlier in their progression.

"The thyroid cancer test has historically been a fairly challenging immunoassay, because it produces a lot of false positives and false negatives, so it wasn't clear if our test would have an advantage," said study co-author Peter Robinson.

"We suspected ours would be more sensitive, but we were pleasantly surprised by the magnitude," Robinson noted.

Based on the success of the thyroid screening, the group has won a few grants to advance the technique into clinical trials for screening other diseases including HIV.​

New York, March 20 (IANS)

​London, March 20 (IANS) A team of German scientists has found out what actually happens if we try to remember things that took place years or decades ago?

The study revealed that the neural networks involved in retrieving very old memories are quite distinct from those used to remember recent events.

"For the very first time we were able to show that the retrieval of old and recent memories are supported by distinct brain networks," said Magdalena Sauvage, professor at Ruhr-University Bochum in Germany.

When we remember events which occurred recently, the hippocampus -- the portion of the brain, thought to be the centre of emotion, memory, and the autonomic nervous system -- is activated, said the paper appeared in the journal eLIFE.

Hippocampus contains the cornu ammonis regions 1 and 3 (CA1 and CA3), which plays a major role in retrieving recent memories.

For the study, the team monitored brain activity in mice during the retrieval of memories that are one day to one year old - e.g. up to the mouse-equivalent of 40 human years.

For their study they applied a high-resolution molecular imaging technique, which detects the expression of a particular gene tied to plasticity processes and this way sheds light on cognitive processes.

The CA3 region, believed to be the place of memory storage in the hippocampus, no longer plays a role when we remember very old memories.

Rather, the involvement of the CA1 region persists and the cortical areas -- largest part of the brain -- adjacent to the hippocampus become involved.

The reason for the differential involvement of the hippocampal sub-regions could lie in the mechanisms supported by CA3.

In CA3, memories can be retrieved on the basis of single features of an original memory, which are used as cues. 

"Since the memory for single features degrades over time, we speculate that they might ultimately be of no more use as cues, hence retrieving memory would then essentially rely on CA1 and other processes taking place in the parahippocampal region of the brain," explained Sauvage.​

​Cape Town, March 20 (IANS) South Africans actively took part in the Earth Hour campaign by switching off lights from 8.30-9.30 p.m., saving an average of 515 mw electricity during the hour, authorities said on Sunday.

As part of its support for the Earth Hour campaign, the country's electricity utility Eskom measured the reduction in electricity used during the hour on Saturday, Xinhua reported.

"We would like to encourage people to take action beyond this one hour, and to make energy efficiency and environmental conservation part of their daily lifestyles," Eskom said.

People are encouraged to reduce their energy consumption every day by using electricity efficiently, and switching off all non-essential lights and household appliances, said the utility.

Commercial customers, particularly shopping centres and office blocks, can also make a big difference by switching off non-essential lights and not leaving office equipment such as computers in standby mode after hours, it added.

Earth Hour is an annual global event, initiated in Sydney, in 2007 to encourage people to switch off lights and unused appliances for an hour as a symbolic demonstration of their commitment to action against climate change.​

​London, March 21 (IANS) For mothers-to-be, going for an MRI of the cervix area can give more accurate results than ultrasound to predict if some women will give a preterm birth, say researchers.

Early dilation of the cervix, a neck of tissue connecting the uterus with the vagina, during pregnancy can lead to premature delivery. 

Women in their second trimester of pregnancy with a cervix measuring 15 millimeters or less, as seen on ultrasound, are considered to be at higher risk of preterm birth. 

However, ultrasound has limitations as a predictor of preterm birth, as it does not provide important information on changes in cervical tissue in the antepartum phase just before childbirth.

"A better understanding of the process of antepartum cervical remodeling, loosely divided in two distinct phases called softening and ripening, is critical to improve the diagnosis of cervical malfunction and anticipate the occurrence of birth," explained lead study author Gabriele Masselli from Sapienza University in Rome.

To learn more, researchers used an MRI technique called diffusion-weighted imaging (DWI) to examine pregnant women who had been referred for suspected fetal or placental abnormality. 

DWI has been increasingly used for abdominal and pelvic diseases, but has not been tested for the evaluation of the uterine cervix in pregnant patients.

Each of the 30 pregnant women in the study, published in the Journal of Radiology, had a sonographically short cervix and a positive fetal fibronectin test between 23 and 28 weeks of gestation. 

Fetal fibronectin is a glue-like protein that helps hold the fetal sac to the uterine lining and the presence of it before week 35 of gestation may indicate a higher risk of preterm birth.

Of the 30 women, eight delivered within a week of the MRI examination. The other 22 delivered an average of 55 days later. 

The researchers analysed the difference between an MRI and ultrasound method.

"Our results suggest that MRI has emerged as a powerful imaging biomarker in evaluating patients with impending delivery," the authors stated.​

​Toronto, March 21 (IANS) Astrophysicists from York University have revealed the fastest winds ever seen at ultraviolet wavelengths near a supermassive black hole.

“We’re talking wind speeds of 20 percent the speed of light which is more than 200 million kms per hour. That’s equivalent to a category 77 hurricane,” said Jesse Rogerson who led the research as part of his PhD thesis in the Department of Physics and Astronomy at York. 

"We have reason to believe that there are quasar winds that are even faster," he added.

Astronomers have known about the existence of quasar winds since the late 1960s. At least one in four quasars have them. 

Quasars are the discs of hot gas that form around supermassive black holes at the centre of massive galaxies - they are bigger than Earth’s orbit around the sun and hotter than the surface of the sun, generating enough light to be seen across the observable universe.

“Black holes can have a mass that is billions of times larger than the sun, mostly because they are messy eaters in a way, capturing any material that ventures too close,” added associate professor Patrick Hall.

As matter spirals toward a black hole, some of it is blown away by the heat and light of the quasar. 

"These are the winds that we are detecting," Hall stated.

The team used data from a large survey of the sky known as the "Sloan Digital Sky Survey" to identify new outflows from quasars. 

After spotting about 300 examples, they selected about 100 for further exploration, collecting data with the Gemini Observatory’s twin telescopes in Hawaii and Chile, in which Canada has a major share.

"We not only confirmed this fastest-ever ultraviolet wind, but also discovered a new wind in the same quasar moving more slowly, at only 140 million kilometres an hour," says Hall. 

"We plan to keep watching this quasar to see what happens next, the authors noted in a paper which appeared in the journal Monthly Notices of the Royal Astronomical Society.

​London, March 21 (IANS) Have you ever failed to notice your phone vibrating or have been pick-pocketed while searching for a friend's face in a crowded place? It is because you were so much engrossed in the visual task that you actually lost the ability to notice that your own wallet was being picked.

According to a new study, people's ability to notice the sense of touch is reduced when they are carrying out a demanding visual task.

The study pointed out an example of cars that now come fixed with tactile alerts and signals the driver when it begins to drift across lanes. 

However, the researchers said that the drivers are less likely to notice these alerts when engaging in demanding visual tasks such as searching for directions at a busy junction. 

"Our research is particularly important given the growing use of tactile information in warning systems,” said Sandra Murphy of Royal Holloway, University of London, in a paper detailed in the Journal of Experimental Psychology: Human Perception and Performance.

For the study, the team asked volunteers to perform a letter search task of either low or high difficulty, as well as respond to the presence or absence of a brief vibration delivered simultaneously to either the left or the right hand. 

Their sensitivity to the clearly noticeable tactile stimulus was reduced when they carried out the more taxing visual search task, the authors reported.

​London, March 21 (IANS) A team of British researchers has discovered how the immune system stops bacteria in our gut from leaking into the blood stream that may help in treatment and prevention of life threatening infections.

If the bacteria escape from the gut into the bloodstream, they can cause infections elsewhere in the body that become deadly if left untreated.

"Gut barrier injury can lead to the often deadly disease known as sepsis, which is one of the biggest killers of critically-ill patients”," said Chengcan Yao from the University Of Edinburgh. 

"Our study reveals a new approach that could be exploited as a treatment to help prevent one of the common causes of sepsis," Yao added.

The study, published in the journal Science, also helps explain why we do not suffer more infections, despite the vast number of bacteria that are found naturally in our gut.

Their escape is triggered by an immune system failure that causes a massive inflammatory response. This damages healthy tissues and can lead to multiple organ failure.

They found that a small molecule called "PGE2" plays a crucial role by activating specialised immune cells called innate lymphoid cells. These cells help to maintain the barrier between the gut and the rest of the body.

If "PGE2" is blocked or doesn't function correctly, these cells are not activated and the gut barrier breaks down allowing bacteria to escape.

The findings could lead to new approaches for preventing whole-body infections which can be life threatening if they are not caught early.

"Sepsis is often difficult to diagnose and treat, therefore, better understanding of the immune mechanisms involved will help us to devise strategies to improve patient prognosis," added study co-author Rodger Duffin.​