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Comment by Dr. Krishna Kumari Challa on August 22, 2015 at 8:56am

Every year, more strains of bacteria develop resistance to the antibiotics we use to treat deadly infections. At The Scripps Research Institute (TSRI) scientists have been working to develop new forms of these drugs, including an antibiotic called arylomycin—but tests have shown that it is possible for bacteria to become resistant to arylomycin, too.

Now, scientists at TSRI have discovered that the important human pathogen Staphylococcus aureus, develops resistance to this drug by “switching on” a previously uncharacterized set of genes.

“This explains why antibiotic resistance rates in some bacteria are higher than in others,” said TSRI Professor Floyd Romesberg, senior author of the new study. “Resistance depends on this little set of genes that no one knew could contribute to tolerating the arylomycins.”

These findings were published this week by the journal mBio.
"An Alternative Terminal Step of the General Secretory Pathway in Staphylococcus aureus"
http://mbio.asm.org/content/6/4/e01178-15

Comment by Dr. Krishna Kumari Challa on August 22, 2015 at 8:52am

Treatments for the same opportunistic bacteria found in cystic fibrosis patients can work in one area in the lung and be less effective in others. The reason, reported August 20 in Cell Host & Microbe, is that bacteria become isolated from one another and evolve region-specific traits. Researchers saw differences in bacterial nutritional requirements, host defenses, and antibiotic resistance. The findings suggest that other chronic infections may yield similar bacterial diversity.

To understand how chronic bacterial infections persist in the face of antibiotics and immune defenses, researchers from the University of Washington School of Medicine dissected human lungs removed from patients with cystic fibrosis at the time of lung transplantation and collected thousands of one type of bacteria, pseudomonas, from different lung regions. The team found that while all of the pseudomonas in a lung were descendants of a single strain, each region contained a vast array of sibling bacteria that functioned differently.

"What made this so important to us is that the bacterial populations inhabiting different lung regions varied dramatically in terms of their antibiotic resistance and virulence," says lead author Dr. Peter Jorth. "This diversity could affect the patients' health."

When the investigators analyzed the genetic codes of the bacteria, the DNA sequences revealed that diversity arose because bacterial cells had become isolated in different lung regions and then evolved locally, much like Darwin's famed finches in the Galapagos.

The DNA sequences also suggest that traits that evolved over years or even decades may persist in bacteria inhabiting different lung regions and may provide a type of "memory" of past conditions and treatments that strengthen the bacteria.

"Even when a single strain of bacteria causes a chronic infection, evolution with human organs can produce diverse families of related bacteria," says senior author Dr. Pradeep Singh. "This may be part of what makes treatment so difficult, because when bacteria sensitive to one kind of stress are killed, functionally different siblings are there to take their place."

The researchers' next challenge is to use their understanding of how bacteria change during infection to find new ways to attack the diverse mixtures of bacteria that are present and to improve treatment for patients.
http://www.sciencedirect.com/science/article/pii/S193131281500298X
Bacteria Evolve Differences within the Lungs of Patients with Cystic Fibrosis

Comment by Dr. Krishna Kumari Challa on August 22, 2015 at 8:49am

Scientists have exposed a chink in the armour of disease-causing bugs, with a new discovery about a protein that controls bacterial defences. Bacteria react to stressful situations - such as running out of nutrients, coming under attack from antibiotics or encountering a host body’s immune system - with a range of defence mechanisms. These include constructing a resistant outer coat, growing defensive structures on their surface or producing enzymes that break down the DNA of an attacker.

The new research shows that a protein called sigma54 holds a bacterium’s defences back until it encounters stress, at which point the protein rearranges its structure to trigger the defences into action. The range of defences that sigma54 controls is so broad that the scientists are moving quickly to learn how to block its action and disable some of the bacteria's armour with new antibiotics.

The findings of the study are published recently in the journal Science by researchers at Imperial College London with collaborators at Peking University in China, Pennsylvania State University and University of Wisconsin-Madison, in the USA.

Structures of the RNA polymerase-s54 reveal new and conserved regulatory strategies. Yun Yang, Vidya C. Darbari, Nan Zhang, Duo Lu, Robert Glyde, Yiping Wang, Jared Winkelman, Richard L. Gourse, Katsuhiko S. Murakami, Martin Buck, Xiaodong Zhang. Science, 2015
Science news source:
Imperial College London

Comment by Dr. Krishna Kumari Challa on August 21, 2015 at 7:12am

Who do you think is the top predator in the world? It is the human being, according to scientists!

''The unique ecology of human predators''

Humans are a unique “super-predator” that hunts and kills other species many times more efficiently than the other top predators both on land and sea, scientists have found.

A study into the effectiveness of predatory animals has placed people head and shoulders above other top carnivores such as the lion and wolf on land and the shark and killer whale in the sea.

The researchers estimate that ocean fishing has resulted in humans exploiting adult fish populations at about 14 times the rate of other marine predators, while humans have hunted and killed adult land animals at around nine times the rate of other animal predators.

Human hunting and fishing has had an extraordinary impact on the natural world and its ruthless efficiency is laid bare in a detailed survey of 2,125 species of terrestrial and marine predators around the world, published in the journal Science.

The study revealed that human hunting and fishing is qualitatively different to the predatory behaviour shown by other species. It has, for instance, concentrated on killing mature adult animals rather than their offspring, which the scientists have likened to eating into the “reproductive capital” rather than the “reproductive interest” of the natural world.

The study found that humans show another remarkable hunting trait by their ability to target other top predators as potential prey, especially in the sea where the decimation of top carnivores such as sharks, tuna fish and marlin has fundamentally changed the balance of some marine ecosystems.

Our impacts are as extreme as our behaviour and the planet bears the burden of our predatory dominance….These are extreme outcomes that non-human predators seldom impose.

Some herbivore populations kept in check by neither predators nor diseases have exploded, robbing food resources from a diversity of life, from insects important to humanity to birds we cherish, according to the scientists.

http://www.sciencemag.org/content/349/6250/858

Comment by Dr. Krishna Kumari Challa on August 21, 2015 at 6:07am

Computers from DNA:
Scientists have found a way to 'switch' the structure of DNA using copper salts and EDTA (Ethylenediaminetetraacetic acid) - an agent commonly found in shampoo and other household products.

It was previously known that the structure of a piece of DNA could be changed using acid, which causes it to fold up into what is known as an 'i-motif'.

But new research published today in the journal Chemical Communications reveals that the structure can be switched a second time into a hair-pin structure using positively-charged copper (copper cations). This change can also be reversed using EDTA.

The applications for this discovery include nanotechnology - where DNA is used to make tiny machines, and in DNA-based computing - where computers are built from DNA rather than silicon.

It could also be used for detecting the presence of copper cations, which are highly toxic to fish and other aquatic organisms, in water.
A potential application of this finding could be to create logic gates for DNA based computing. Logic gates are an elementary building block of digital circuits - used in computers and other electronic equipment. They are traditionally made using diodes or transistors which act as electronic switches.

"This research expands how DNA could be used as a switching mechanism for a logic gate in DNA-based computing or in nano-technology."

'Reversible DNA i-motif to hairpin switching induced by copper (ii) cations' is published in the journal Chemical Communications.

http://phys.org/news/2015-08-uea-dna.html#jCp

Comment by Dr. Krishna Kumari Challa on August 21, 2015 at 6:02am

How to keep surfaces dry underwater is what is bothering the scientific community for a long time. Now we might have found the answers to teh question.
Northwestern Univ. engineers have examined a wide variety of surfaces that can do just that—and, better yet, they know why.

The research team is the first to identify the ideal "roughness" needed in the texture of a surface to keep it dry for a long period of time when submerged in water. The valleys in the surface roughness typically need to be less than one micron in width, the researchers found. That's really small—less than one millionth of a meter—but these nanoscopic valleys have macroscopic impact.

Understanding how the surfaces deflect water so well means the valuable feature could be reproduced in other materials on a mass scale, potentially saving billions of dollars in a variety of industries, from antifouling surfaces for shipping to pipe coatings resulting in lower drag. That's science and engineering, not serendipity, at work for the benefit of the economy.
The trick is to use rough surfaces of the right chemistry and size to promote vapor formation, which we can use to our advantage. When the valleys are less than one micron wide, pockets of water vapor or gas accumulate in them by underwater evaporation or effervescence, just like a drop of water evaporates without having to boil it. These gas pockets deflect water, keeping the surface dry, according to the new finding.
In a study published by Scientific Reports, Patankar and his co-authors explain and demonstrate the nanoscale mechanics behind the phenomenon of staying dry underwater.
The researchers also report that nature uses the same strategy of surface roughness in certain aquatic insects, such as water bugs and water striders. Small hairs on the surfaces of their body have the less-than-one-micron spacing, allowing gas to be retained between the hairs.
The researchers focused on the nanoscopic structure of surfaces, which, at the nanoscale, are somewhat akin to the texture of a carpet, with tiny spike-like elevations separated by valley-shaped pores in between.

When submerged, water tends to cling to the top of the spikes, while air and water vapor accrue in the pores between them. The combination of trapped air and water vapor within these cavities forms a gaseous layer that deters moisture from seeping into the surface below. When the researchers looked at the rough surfaces under the microscope, they could see clearly the vacant gaps—where the protective water vapor is.
They demonstrated that when the valleys are less than one micron in width, they can sustain the trapped air as well as vapor in their gasified states, strengthening the seal that thwarts wetness.

Source: Northwestern Univ.

http://www.rdmag.com/news/2015/08/engineers-identify-how-keep-surfa...

Comment by Dr. Krishna Kumari Challa on August 19, 2015 at 9:36am

Antibiotic resistance in wild life is mainly because of  Water.  It seems to be the most important medium exposing animals to antibiotic resistance, with water-associated species such as hippos and waterbucks having higher levels of multi-drug resistant microorganisms.

• Bacteria from wildlife and humans have similar resistance

• Resistance could accumulate up the food chain

• Approach may allow early detection of antimicrobial resistance epidemics

In addition, bacteria resistant to multiple drugs were more common in animals, such as baboons, warthogs and mongooses, which live in urbanised areas, and in carnivorous species.
Resistance may accumulate up the food chain making apex predators such as crocodile, leopard and hyena important ecosystem sentinels.

Studying wild animals helps to understand how resistance moves from humans and farming systems across ecosystems and ultimately back to humans.

http://www.scidev.net/global/disease/news/wildlife-warning-antibiot...

Comment by Dr. Krishna Kumari Challa on August 19, 2015 at 8:59am

Delayed Development of Brain Connectivity in Adolescents With Schizophrenia and Their Unaffected Siblings
Some Siblings can overcome Schizophrenia Risk by altering their genetic predisposition to the disease.
Despite their shared genetic predisposition to schizophrenia, siblings of patients with childhood-onset schizophrenia are eventually able to catch up with normally developing peers. The study documenting these findings, published in JAMA Psychiatry, opens up new avenues for treating the hugely debilitating condition. “The greatest risk for schizophrenia is family history, but the majority of siblings of individuals with the disorder are unaffected,” said Dr. Andrew Zalesky from the University of Melbourne, lead author of the study. “So why are these brothers and sisters able to overcome the risk? Looking for these biological factors that protect a person from developing schizophrenia opens up a new direction in the search for treatments.” Zalesky and his team used magnetic resonance imaging (MRI) to map the brains of 109 children with childhood-onset schizophrenia (COS), from ages 12 to 24. They compared the images with scans taken of the participants’ brothers and sisters without COS to see if similar brain changes took place over time. The siblings without COS showed similar delays in brain connectivity while growing up, but these connections tended to normalise or ‘catch up’ to those of normally developing adolescents. Zalesky said the ability of the siblings to catch up and develop important brain circuitry means there is a degree of resilience to their risk for schizophrenia.
http://archpsyc.jamanetwork.com/article.aspx?articleid=2396494

Comment by Dr. Krishna Kumari Challa on August 19, 2015 at 8:55am

Abrupt changes in Indian summer monsoon strength during 33,800 to 5500 years B.P.
Abstract

Speleothem proxy records from northeastern (NE) India reflect seasonal changes in Indian summer monsoon strength as well as moisture source and transport paths. We have analyzed a new speleothem record from Mawmluh Cave, Meghalaya, India, in order to better understand these processes. The data show a strong wet phase 33,500–32,500 years B.P. followed by a weak/dry phase from 26,000 to 23,500 years B.P. and a very weak phase from 17,000 to 15,000 years B.P. The record suggests abrupt increase in strength during the Bølling-Allerød and early Holocene periods and pronounced weakening during the Heinrich and Younger Dryas cold events. We infer that these changes in monsoon strength are driven by changes in temperature gradients which drive changes in winds and moisture transport into northeast India.

http://onlinelibrary.wiley.com/doi/10.1002/2015GL064015/abstract

Comment by Dr. Krishna Kumari Challa on August 19, 2015 at 8:44am

Acoustic stealth - this is what gives owls an edge over their prey...
A new study says ... Owls are equipped with state-of-the-art stealth technology to help them swoop on prey undetected.
The night hunters have feathers that absorb aerodynamic sound and suppress the vibrations that occur when a bird flaps its wings.

During flight, an owl’s feathers extract mechanical energy and convert it into heat. The result is perfect silence as the bird approaches to within inches of a mouse or vole.
Scientists used lasers and high-speed cameras to analyse and compare long-eared owl, eagle, and pigeon feathers during flight.
While differing in size, all three birds have a similar “flapping” style.

Lead researcher Jinkui Chu, from Dalian University of Technology in China, said: “Many owls have a unique and fascinating ability to fly so silently that they are out of their prey’s hearing range, due to their feather structure.

“This behaviour has long been of interest to engineers, as we seek to apply the owl’s noise-reduction mechanisms to other purposes and situations that benefit society.

“Now, however, we know the owls’ silent flight ability is even more superior than we thought.

“You could say of all birds it is the ‘king of acoustic stealth’. It not only manages to suppress aerodynamic noise when gliding, but also mechanical noise caused by vibration during flying.

“This is remarkable, considering the sudden jumping, bending and twisting the wings are subjected to when flapping and the noise that creates for other birds.

“In the scientific world, the process used to eliminate this mechanical noise is called ’damping’ — which means the extraction of mechanical energy from a vibrating system usually by converting it into heat and allowing it to remain steady.”

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