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Comment by Dr. Krishna Kumari Challa on April 25, 2014 at 7:27am

Animal Kingdom Communication
UM researcher discovers the most effective animal signal strategies.
There are all sorts of signaling strategies in nature. Peacocks puff out their feathers and spread their colorful tails; satin bowbirds build specialized stick structures, called bowers, and decorate them with blue and shiny objects; and European bitterling males show off bright nuptial coloration during spawning season. Each species has evolved a unique method to communicate with others.
“Signaling can have profound fitness implications for individuals that are either signaling or receiving the signal,” says Gavin M. Leighton, author of a new study on the effectiveness of signaling systems.

“For instance, individuals may signal to attract mates, or they may signal to rivals in order to defend a territory. Additionally, many biological models of cooperative behavior require individuals to signal how cooperative they were in past interactions.”
Effective communication is not just about the signaler, according to the study, the receiver also needs to assess the signaler efficiently. For instance, one of the most effective strategies from the perspective of female birds is assessing groups of males called leks, where females can assess multiple males in a short period of time.
“When receivers had to assess individual signalers one at a time, the accuracy of their ranking of signalers decreased compared to when all the signalers could be observed simultaneously.”
The study also shows that individuals that used non-food items, like a twig, in their signaling display had the least effective strategy. Surprisingly, individuals that invest in ecological structures, such as building a nest, improved the ability of the females to rank signalers, but the effect was fairly weak.
“The most unexpected finding was that investing in some sort of temporally stable structure only weakly improved the ability for receivers to assess signalers,” Leighton, said. “I originally suspected that investing in a structure would allow individuals to quickly convey their signaling effort over time in a single, observable feature. While I did find that structures helped, the effect was not as strong as other the other variables.”
In order to investigate specific characteristics of systems and provide the ranking of signalers by receivers, Leighton designed a computer model that represents salient features of many signaling systems, across a variety of scenarios. The model is called an agent-based model. It allows the researcher to program individual entities with specified behaviors. Then, the software provides the ranking information to the researcher. Included in the analyses were different species of birds, fishes and insects.

“The study systematically models a series of behavioral and ecological conditions. To the best of my knowledge no one has performed a general analysis of these different types of signaling systems.”
The study assumes that in every scenario individuals had perfect memory. In other words, when a receiver saw a signaling individual, they were able to unambiguously assign this effort to a specific individual. In nature, individuals probably make errors in assigning signaling effort or forget the effort of individuals over time.
“By itself, this seems like an unwarranted assumption, however, it is not easy to compare across signaling systems where memory also varies with the species in question,” Leighton says.
In the future, the researcher would like to include variation in the memory of individual receivers in these models. “There may be effects of imperfect memory that influence signaling effectiveness and I think this would be a good next step.”
http://www.miami.edu/index.php/news/releases/animal_kingdom_communi...

Comment by Dr. Krishna Kumari Challa on April 25, 2014 at 6:16am

Risk factors for food allergy.

The dual-allergen exposure hypothesis is the theory that exposure to food allergens through the skin can lead to allergy, while consumption of these foods at an early age may actually result in tolerance. Depending on the balance of these exposures, either tolerance or allergy will “win.” Children with eczema, for example, have a disrupted skin barrier that could allow exposure to food proteins in the environment – such as peanut oil in creams or peanut residue on tables. Under the hypothesis, if these children avoid peanuts but are still exposed to them in the environment, they might be more likely to develop peanut allergy.

http://blogs.scientificamerican.com/food-matters/2014/04/23/prevent...

Despite efforts to prevent food allergy (FA) in children, IgE-mediated FAs are increasing in westernized countries. Previous preventive strategies, such as prolonged exclusive breast-feeding and delayed weaning onto solid foods, have recently been called into question. The present review considers possible risk factors and theories for the development of FA. An alternative hypothesis is proposed, suggesting that early cutaneous exposure to food protein through a disrupted skin barrier leads to allergic sensitization and that early oral exposure to food allergen induces tolerance. Novel interventional strategies to prevent the development of FA are also discussed.
http://www.ncbi.nlm.nih.gov/pubmed/22464642

Comment by Dr. Krishna Kumari Challa on April 25, 2014 at 5:29am

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 9:04am

Agenetic disease has been cured in living, adult animals for the first time using a revolutionary genome-editing technique that can make the smallest changes to the vast database of the DNA molecule with pinpoint accuracy.

Scientists have used the genome-editing technology to cure adult laboratory mice of an inherited liver disease by correcting a single "letter" of the genetic alphabet which had been mutated in a vital gene involved in liver metabolism. A similar mutation in the same gene causes the equivalent inherited liver disease in humans — and the successful repair of the genetic defect in laboratory mice raises hopes that the first clinical trials on patients could begin within a few years, scientists said.

The success is the latest achievement in the field of genome editing. This has been transformed by the discovery of Crispr, a technology that allows scientists to make almost any DNA changes at precisely defined points on the chromosomes of animals or plants.

Crispr — pronounced "crisper" — was initially discovered in 1987 as an immune defence used by bacteria against invading viruses. Its powerful genome-editing potential in higher animals, including humans, was only fully realised in 2012 and 2013 when scientists showed that it can be combined with a DNAsniping enzyme called Cas9 and used to edit the human genome . Since then there has been an explosion of interest in the technology because it is such a simple method of changing the individual letters of the human genome — the 3 billion "base pairs" of the DNA molecule — with an accuracy equivalent to correcting a single misspelt word in a 23-volume encyclopaedia.

In the latest study, scientists at the Massachusetts Institute of Technology (MIT) used Crispr to locate and correct the single mutated DNA base pair in a liver gene known as LAH, which can lead to a fatal build-up of the amino acid tyrosine in humans and has to be treated with drugs and a special diet. The researchers effectively cured mice suffering from the disease by altering the genetic make-up of about a third of their liver cells using the Crispr technique, which was delivered by high-pressure intravenous injections.

"We basically showed you could use the Crispr system in an animal to cure a genetic disease, and the one we picked was a disease in the liver which is very similar to one found in humans," said professor Daniel Anderson of MIT, who led the study.

"The disease is caused by a single point mutation and we showed that the Crispr system can be delivered in an adult animal and result in a cure. We think it's an important proof of principle that this technology can be applied to animals to cure disease," Anderson said. "The fundamental advantage is that you are repairing the defect , you are actually correcting the DNA itself," he said. "What is exciting about this approach is that we can actually correct a defective gene in a living adult animal."

Jennifer Doudna, of the University of California, Berkeley , who was one of the codiscoverers of the Crispr technique , said professor Anderson's study is a "fantastic advance" because it demonstrates that it is possible to cure adult animals living with a genetic disorder.

"Obviously there would be numerous hurdles before such an approach could be used in people, but the simplicity of the approach, and the fact that it worked, really are very exciting," professor Doudna said. "I think there will be a lot of progress made in the coming one to two years in using this approach for therapeutics and other real-world applications," she added.
''Scientists ‘edit’ DNA to correct adult genes and cure diseases ''
http://www.independent.co.uk/news/science/revealed-scientists-edit-...

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 8:57am

Parts of Antarctica, one of the coldest places on Earth, were as warm as today's California coast about 40 million years ago with temperatures as high as 17 degrees Celsius, a new study has found.

Researchers also found that the polar regions of the southern Pacific Ocean once registered 21st-century Florida heat.

The findings underscore the potential for increased warmth at Earth's poles and the associated risk of melting polar ice and rising sea levels, the researchers said.

Led by scientists at Yale University, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate.

Today, Antarctica is year-round one of the coldest places on Earth, and the continent's interior is the coldest place, with annual average land temperatures far below zero degrees Fahrenheit.

The new measurements can help improve climate models used for predicting future climate, according to co-author Hagit Affek, associate professor of geology & geophysics at Yale.
-PTI

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 8:55am

Research at the University of Adelaide has shed new light onto the possible causes of sudden infant death syndrome (SIDS), which could help to prevent future loss of children’s lives.

Researchers in the University’s School of Medical Sciences have found that telltale signs in the brains of babies that have died of SIDS are remarkably similar to those of children who died of accidental asphyxiation.
'β-Amyloid precursor protein staining of the brain in sudden infant and early childhood death'
http://onlinelibrary.wiley.com/doi/10.1111/nan.12109/abstract;jsess...

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 8:53am

Mechanisms of charge transfer and redistribution in LaAlO3/SrTiO3 revealed by high-energy optical conductivity
Researchers from Singapore and Germany have found a new way to study the curious properties observed at the interface of materials.
An international team led by researchers at the National University of Singapore (NUS) has developed a technique to study the interface between materials, shedding light on the curious properties that arise when two materials are put together.

Studying material interfaces is part of a research area known as condensed matter physics. When matter is condensed, mutual interactions between particles alters physical behavior, giving rise to exotic properties. A better understanding of how materials interface allows scientists to tweak material properties to possibly develop better solar cells, superconductors and smaller hard drives.

“If you put two materials together, you can create completely new properties. For instance, two non-conducting, non-magnetic insulators can become conducting and in some cases ferromagnetic and superconducting at their interface,” explains NUS Assistant Professor Andrivo Rusydi, who led the research.

The team investigated the electrical conductivity of strontium titanate and lanthanum aluminate, two insulators that become conductors at their interface. They observed that conductivity was ten-fold less than what was predicted theoretically, meaning that 90 percent of the expected electrons were missing.

To find the missing electrons, the team used high-energy reflectivity and spectroscopic ellipsometry experiments which flooded the interface with a wide range of energy. This revealed electrons that were bound within the molecular lattice, which prevented them from moving and explained the observed low conductivity.

The team’s new approach and insights, which culminated in a recent publication with Nature Communications, will be used for further investigations on the basic interface characteristics among materials.

http://www.nature.com/ncomms/2014/140414/ncomms4663/full/ncomms4663...

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 8:51am

Citizen scientists pitch new uses for paper microscope
Ten thousand ‘print-and-fold’ paper microscopes initially designed as low-cost medical diagnostic tools are being given away to researchers and citizen scientists who come up with novel ways to use them to test their ideas.

The goal of the Ten Thousand Microscopes initiative, funded by the Gordon and Betty Moore Foundation, is to create a crowdsourced lab manual for Foldscope, the low-cost microscope launched earlier this year by a US bioengineering team that combines pragmatic, origami design with sophisticated micro-optics.

The idea is to make “microscopy for everyone”, says Manu Prakash, a bioengineering researcher at Stanford University, United States, who led the development of the frugal innovation to address the lack of cheap, easy-to-use diagnostic tools for diseases in remote and impoverished communities.
http://www.scidev.net/global/biotechnology/news/citizen-scientists-...

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 8:32am

Cow poop promotes the spread of antibiotic resistant bacteria

Manure from dairy cows has been defined as an increasing source of bacteria that can become resistant to antibiotics. These findings are the result of the work of Fabienne Wichmann and colleagues at Yale University in New Haven, Connecticut. The research was published in the April 22, 2014, edition of the journal mBio®.

Bacteria that are antibiotic resistant reach the food chain of humans through the use of cow manure as fertilizer. The manure may or may not contain bacteria that are antibiotic resistant. If the manure does contain an antibiotic resistant strain of bacteria then there is a potential for transmission to humans that eat food that was fertilized with cow manure. The food plants can even become a source of antibiotic resistance due to the phenomenon of gene exchange between species.

A more prominent and more likely transfer of new antibiotic bacterial species to humans is through infection of cow farmers by new bacterial strains. The dairy cow farmers can transmit a new disease directly to other humans through physical contact or through airborne distribution during coughing or sneezing. The more humans that come into contact with a potentially antibiotic resistant type of bacteria increases the probability that the bacteria will become resistant to antibiotics due in part to the high level of use of antibiotics by humans.

The researchers found that only five samples of cow manure contained 80 unique and functional antibiotic resistance genes. The scientists created a laboratory cultured strain of Escherichia coli that was resistant to one of the four major types of antibiotics used to treat humans from the 80 genes. The scientists also found a never before known family of antibiotic resistant genes that conferred resistance to the same group of antibiotics.

A primary source of antibiotic resistant bacteria origination is the use of antibiotics to keep cattle healthy. The potential for transfer of antibiotic resistance to humans through food crops depends on whether the cow manure has antibiotic resistant bacteria or genes. It is possible that a new antibiotic resistant disease could be contracted by people simply by using cow manure as fertilizer for their house plants or home garden.
Source: http://www.examiner.com/article/cow-poop-promotes-the-spread-of-ant...

Comment by Dr. Krishna Kumari Challa on April 23, 2014 at 7:10am

Antibiotics: A new spanner in the works of bacterial transcription
A promising molecular target that is unlikely to develop antibiotic resistance has been identified in bacteria.
http://elifesciences.org/content/3/e02840

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