Comment

Comment by Dr. Krishna Kumari Challa on September 24, 2014 at 6:33am

Active invasion of bacteria into living fungal cells
The rice seedling blight fungus Rhizopus microsporus and its endosymbiont Burkholderia rhizoxinica form an unusual, highly specific alliance to produce the highly potent antimitotic phytotoxin rhizoxin. Yet, it has remained a riddle how bacteria invade the fungal cells. Genome mining for potential symbiosis factors and functional analyses revealed that a type 2 secretion system (T2SS) of the bacterial endosymbiont is required for the formation of the endosymbiosis. Comparative proteome analyses show that the T2SS releases chitinolytic enzymes (chitinase, chitosanase) and chitin-binding proteins. The genes responsible for chitinolytic proteins and T2SS components are highly expressed during infection. Through targeted gene knock-outs, sporulation assays and microscopic investigations we found that chitinase is essential for bacteria to enter hyphae. Unprecedented snapshots of the traceless bacterial intrusion were obtained using cryo-electron microscopy. Beyond unveiling the pivotal role of chitinolytic enzymes in the active invasion of a fungus by bacteria, these findings grant unprecedented insight into the fungal cell wall penetration and symbiosis formation.
http://elifesciences.org/content/3/e03007

Comment by Dr. Krishna Kumari Challa on September 24, 2014 at 6:26am

T cell-specific inhibition of multiple apoptotic pathways blocks negative selection and causes autoimmunity

T cell self-tolerance is thought to involve peripheral tolerance and negative selection, involving apoptosis of autoreactive thymocytes. However, evidence supporting an essential role for negative selection is limited. Loss of Bim, a Bcl-2 BH3-only protein essential for thymocyte apoptosis, rarely results in autoimmunity on the C57BL/6 background. Mice with T cell-specific over-expression of Bcl-2, that blocks multiple BH3-only proteins, are also largely normal. The nuclear receptor Nur77, also implicated in negative selection, might function redundantly to promote apoptosis by associating with Bcl-2 and exposing its potentially pro-apoptotic BH3 domain. Here, we report that T cell-specific expression of a Bcl2 BH3 mutant transgene results in enhanced rescue of thymocytes from negative selection. Concomitantly, Treg development is increased. However, aged BH3 mutant mice progressively accumulate activated, autoreactive T cells, culminating in development of multi-organ autoimmunity and lethality. These data provide strong evidence that negative selection is crucial for establishing T cell tolerance.
http://elifesciences.org/content/3/e03468#sthash.vBgMe7lK.dpuf

Comment by Dr. Krishna Kumari Challa on September 24, 2014 at 6:19am

Epidemiology: Mapping Ebola in wild animals for better disease control
Identifying the regions where wild animal populations could transmit the Ebola virus should help with efforts to prepare at-risk areas for future outbreaks.
http://elifesciences.org/content/3/e04565

Mapping the zoonotic niche of Ebola virus disease in Africa

Ebola virus disease (EVD) is a complex zoonosis that is highly virulent in humans. The largest recorded outbreak of EVD is ongoing in West Africa, outside of its previously reported and predicted niche. We assembled location data on all recorded zoonotic transmission to humans and Ebola virus infection in bats and primates (1976–2014). Using species distribution models, these occurrence data were paired with environmental covariates to predict a zoonotic transmission niche covering 22 countries across Central and West Africa. Vegetation, elevation, temperature, evapotranspiration, and suspected reservoir bat distributions define this relationship. At-risk areas are inhabited by 22 million people; however, the rarity of human outbreaks emphasises the very low probability of transmission to humans. Increasing population sizes and international connectivity by air since the first detection of EVD in 1976 suggest that the dynamics of human-to-human secondary transmission in contemporary outbreaks will be very different to those of the past.

http://elifesciences.org/content/3/e04395

Comment by Dr. Krishna Kumari Challa on September 23, 2014 at 5:35am

Generation of Macroscopic Singlet States in a Cold Atomic Ensemble
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.113.093601 Quantum Entanglement Creates New State of Matter
Half a million ultracold atoms were linked together in the first-ever “macroscopic spin singlet” state.
Physicists have used a quantum connection Albert Einstein called “spooky action at a distance” to link 500,000 atoms together so that their fates were entwined. The atoms were connected via “entanglement,” which means an action performed on one atom will reverberate on any atom entangled with it, even if the particles are far apart. The huge cloud of entangled atoms is the first “macroscopic spin singlet,” a new state of matter that was predicted but never before realized.

Comment by Dr. Krishna Kumari Challa on September 21, 2014 at 2:47pm

Top 50 science stars of Twitter:
http://news.sciencemag.org/scientific-community/2014/09/top-50-scie...

Comment by Dr. Krishna Kumari Challa on September 20, 2014 at 9:18am

Source diversity among journals cited in Science Times
A content analysis of The New York Times’ Science Times section from 1998 to 2012 found evidence of increased source diversity in use of scientific journals as news sources. Science Times increased the frequency at which it cited journals, the number of different journals that it cited, and the number of disciplines represented by cited journals. The results suggest that online availability of a wide array of scientific journals has changed sourcing behaviors.

http://pus.sagepub.com/content/early/2014/07/24/0963662514542908.ab...

Comment by Dr. Krishna Kumari Challa on September 20, 2014 at 9:15am

Six Reasons Not to Worry about the Higgs Boson Destroying the Universe
https://storify.com/AstroKatie/six-reasons-not-to-worry-about-the-h...

Comment by Dr. Krishna Kumari Challa on September 20, 2014 at 9:02am

Comment by Dr. Krishna Kumari Challa on September 20, 2014 at 8:48am

Here is another warning:
Artificial sweeteners can trigger diabetes
Artificial sweeteners may disrupt the body's ability to regulate blood sugar, causing metabolic changes that can be a precursor to diabetes, researchers are reporting. That is "the very same condition that we often aim to prevent" by consuming sweeteners instead of sugar, said Dr Eran Elinav, an immunologist at the Weizmann Institute of Science in Israel, at a news conference to discuss the findings. The scientists performed a multitude of experiments, mostly on mice, to back up their assertion that the sweeteners alter the microbiome, the population of bacteria that is in the digestive system.

The different mix of microbes, the researchers contend, changes the metabolism of glucose, causing levels to rise higher after eating and to decline more slowly than they otherwise would. The findings by Dr Elinav and his collaborators in Israel, including Eran Segal, a professor of computer science and applied mathematics at Weizmann, are being published Wednesday by the journal Nature.

Cathryn R Nagler, a professor of pathology at the University of Chicago who was not involved with the research but did write an accompanying commentary in Nature, called the results "very compelling." She noted that many conditions, including obesity and diabetes, had been linked to changes in the microbiome. "What the study suggests," she said, "is we should step back and reassess our extensive use of artificial sweeteners."
Previous studies on the health effects of artificial sweeteners have come to conflicting and confusing findings. Some found that they were associated with weight loss; others found the exact opposite, that people who drank diet soda actually weighed more. Some found a correlation between artificial sweeteners and diabetes, but those findings were not entirely convincing: Those who switch to the products may already be overweight and prone to the disease.

While acknowledging that it is too early for broad or definitive conclusions, Dr Elinav said he had already changed his own behaviour.

"I've consumed very large amounts of coffee, and extensively used sweeteners, thinking like many other people that they are at least not harmful to me and perhaps even beneficial," he said. "Given the surprising results that we got in our study, I made a personal preference to stop using them."

In the initial set of experiments, the scientists added saccharin (the sweetener in the pink packets of Sweet'N Low), sucralose (the yellow packets of Splenda) or aspartame (the blue packets of Equal) to the drinking water of 10-week-old mice. Other mice drank plain water or water supplemented with glucose or with ordinary table sugar. After a week, there was little change in the mice who drank water or sugar water, but the group getting artificial sweeteners developed marked intolerance to glucose. Glucose intolerance, in which the body is less able to cope with large amounts of sugar, can lead to more serious illnesses like metabolic syndrome and Type 2 diabetes.

Comment by Dr. Krishna Kumari Challa on September 20, 2014 at 8:16am

Computer simulations point to formamide as prebiotic intermediate in ‘Miller’ mixtures

New Steps Shown Toward Creation of Life by Electric Charge
Simulating a famous experiment to produce life's building blocks by jolting molecules with electricity, scientists may have found a strange new intermediate state .

Localized electrical fields on the surface of minerals may have had a bigger part in prebiotic chemistry than has been appreciated.

Short-range, localized electric fields on the surface of minerals may have played a part in directing the chemistry that led to the molecules of life, according to this new study. The work does provide ‘new insights into the idea that electrical discharges, for example lightning, could have played a role in the formation of prebiotic molecules on early Earth’.

However, ‘One criticism is that the authors chose to use a somewhat reduced or hydrogen-rich mixture in their study, whereas the atmosphere on early Earth is thought to have been carbon dioxide rich, which could entail very different chemistry in the presence of an electric field. Similar studies on a more realistic prebiotic mixture could yield interesting predictions for future experiments.
http://www.rsc.org/chemistryworld/2014/09/modelling-points-formamid...

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