November 2013 volume 1, issue 2
Gl bal
education news
A selection of International Articles and Interest Stories in Higher Education
Silver kills bacteria SOURCE: MARK LORCH (Ars Technica)
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http://tinyurl.com/uwcgen-silverkillsbacteria he use of silver in medicine is as old as Western medicine itself. Hippocrates is known to have used it to treat ulcers and wounds, the Romans knew of its healing properties, and its usage continues up until today. In the antibiotic age, interest in silver may have waned, but with urgent need to fight antibiotic-resistant bacteria, there has been a resurgence in its use. A paper published in the journal Science Translation Medicine sheds some light on silver’s success against bacteria as bacteria has been unable to develop a resistance against it. The most important finding is that silver—unlike most antibiotics—works in more than one way. Firstly, silver sticks very strongly to sulphur groups, found in parts of proteins. These groups normally bond to each other, holding the proteins together and keep them folded up in their correct shape. But if silver interacts with sulphur, then the protein cannot fold correctly, and thus it cannot do its job. Secondly, silver interferes with how bacteria use iron which is often held in place within proteins by binding to sulphur. Since silver also interacts with sulphur, it blocks the iron from doing so. And thirdly, silver causes bacteria to produce toxic substances known as reactive oxygen species. These go on to cause damage inside the cell, harming the DNA, proteins, and even the membrane that surround cells. The result of this is that silver causes severe damage to bacteria’s basic biochemistry. In addition, the membranes and walls that surround the bacteria are leakier after the silver treatment, which allows conventional antibiotics inside the cells and causes them to break down. James Collins of Boston University, who led the research, showed that with added silver, less antibiotic drug is needed to kill the bugs. This may be a great result, but it gets better. Silver also reverses antibiotic resistance of E. coli bacteria, making them, once more, susceptible to tetracycline. When silver was added to standard antibiotics such as gentamicin and vancomycin, Collins could treat E. coli infections in the bladder and abdomens of mice. Finally, Collins showed that the mice themselves remain unharmed by silver. If he is able to repeat this work in humans, he may actually have a “silver bullet” for antibiotic resistance.
Stress and dad’s sperm SOURCE: ANOUK VLEUGELS http://tinyurl.com/uwcgen-stessanddadssperm
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or the first time, researchers have found that stress can leave an epigenetic mark on sperm, which altering the offspring’s hypothalamic-pituitary-adrenal (HPA) axis, a part of the brain that deals with responding to stress. The experiment was conducted with preadolescent and adult male mice, in which stress was induced (by confronting the mice with fox urine or foreign objects). Their offspring, both male and female, turned out to have abnormally low reactivity to stress. This can be both an extreme high or very low reactivity which means that an organism cannot respond to changes in its environment. In people, this might cause stress-related mental disorders. “It didn’t matter if dads were going through puberty or in adulthood when stressed before they mated. We’ve shown here for the first time that stress can produce long-term changes to sperm that reprogram the offspring HPA stress axis regulation,” said lead author Tracy Bale, associate professor of neuroscience. “These findings suggest one way in which paternal-stress exposure may be linked to such neuropsychiatric diseases.” The scientists also examined the role of a series of microRNA (miRs) in the sperm – so-called non-coding RNA molecules that contribute to the expression of genes in the offspring, after fertilization. The results showed that in stressed male mice, there was a significant increase in expression of nine miRs. According to the researchers dads may be able to “prepare” their offspring for certain environmental threats. “Next, we are examining the mechanism whereby these sperm miRs act at fertilisation, and then we can think about using them as biomarkers in human diseases,” said Bale. “And then we can begin to predict who has been exposed to what, and to think about prevention or treatment down the road.”
Human eye less mysterious SOURCE: ROSE PASTORE (Popular Science)
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http://tinyurl.com/uwcgen-humaneyelessmysterious
he newest addition to our human anatomy may just be 15 microns thick, but its discovery will make eye surgery safer and simpler. As reported in the journal Ophthalmology, Harminder Dua, a professor at the University of Nottingham, recently found a new layer in the human cornea by injecting air into eyes and then used an electron microscope to scan each separated
layer. This new layer has now been named as “Dua’s layer”. Dua’s team believes that a tear in this layer is the cause of corneal hydrops, a disorder that leads to fluid buildup in the cornea. According to Dua, knowledge of the new layer could dramatically improve outcomes for patients undergoing corneal grafts and transplants. “This is a major discovery that will mean that ophthalmology textbooks will literally need to be re-written,” says Dua. “From a clinical perspective, there are many diseases that affect the back of the cornea which clinicians across the world are already beginning to relate to the presence, absence or tear in this layer.”
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