Posts tagged science
Articles and news from the latest research reports.
The scent of love: Decomposition and male sex pheromones
A team of researchers, led by Christian von Hoermann from Ulm University, Germany, filled olfactometers with different volatile scents and recorded which scents female hide beetles were attracted to. The scents used were pig cadaver, collected at different stages of decay, male pheromone gland extract, synthetic pheromones, and a control, pentane (an organic solvent which was used to extract the other odours).
The females ignored both the control and synthetic pheromone. In fact they pretty much ignored everything apart from the odour of piglet in the dry remains stage, as long as it was enhanced by male pheromones.
Christian von Hoermann explained, “Although cadaver odour alone is not sufficient to attract two to three week-old virgin female hide beetles, it is enough to attract newly emerged males.” Release of pheromones by these males appears to signal the cadaver as an appropriate site for feeding, mating and egg laying. Evolution seems to have ensured that hide beetle females only respond to a mate (or a food source for their larvae) when the other is also present, so that they can optimise the chances of their offspring’s survival.
In a new study, scientists at the Wisconsin Institute for Discovery (WID) at UW-Madison develop a computational approach to determine whether individuals behave predictably. With data from previous fights, the team looked at how much memory individuals in the group would need to make predictions themselves. The analysis proposes a novel estimate of “cognitive burden,” or the minimal amount of information an organism needs to remember to make a prediction.
The research draws from a concept called “sparse coding,” or the brain’s tendency to use fewer visual details and a small number of neurons to stow an image or scene. Previous studies support the idea that neurons in the brain react to a few large details such as the lines, edges and orientations within images rather than many smaller details.
"So what you get is a model where you have to remember fewer things but you still get very high predictive power — that’s what we’re interested in," says Bryan Daniels, a WID researcher who led the study.
The collapse of the Fukushima Dai-ichi Nuclear Power Plant caused a massive release of radioactive materials to the environment. A prompt and reliable system for evaluating the biological impacts of this accident on animals has not been available. Here we show that the accident caused physiological and genetic damage to the pale grass blue Zizeeria maha, a common lycaenid butterfly in Japan. We collected the first-voltine adults in the Fukushima area in May 2011, some of which showed relatively mild abnormalities. The F1 offspring from the first-voltine females showed more severe abnormalities, which were inherited by the F2 generation. Adult butterflies collected in September 2011 showed more severe abnormalities than those collected in May. Similar abnormalities were experimentally reproduced in individuals from a non-contaminated area by external and internal low-dose exposures. We conclude that artificial radionuclides from the Fukushima Nuclear Power Plant caused physiological and genetic damage to this species.
Levels of sleep problems in the developing world are approaching those seen in developed nations, linked to an increase in problems like depression and anxiety.
According to the first ever pan-African and Asian analysis of sleep problems, led by Warwick Medical School at the University of Warwick, an estimated 150 million adults are suffering from sleep-related problems across the developing world.
The results are published in a study in the journal Sleep.
Source: The University of Warwick
The UT Dallas “tag and track” method not only sheds light on how DNA loops form, but also might be adapted to screen drugs for effectiveness against certain viruses that shuffle genetic material, such as HIV.
Until now, scientists primarily had “snapshots” of the initial and final stages of DNA loop formation, with only limited information about what happens during the intermediate steps.
"Scientists have known for more than 30 years that DNA looping is an important part of molecular biology and gene regulation, but until our work, there have been few serious attempts to understand the basic biophysics of the process, … We estimate that using fluorescence-based methods such as this for drug screening could be as much as 10,000 times more efficient than methods that are currently used," -Dr. Stephen Levene, professor of bioengineering, molecular and cell biology, and phyiscs at UT Dallas.
According to new research, meerkats enhance their intelligence through nine different social and asocial mechanisms. What really makes these animals stand out is their intelligent coordinated behaviour, which rivals that of chimps, baboons, dolphins and even humans in its complexity and efficiency.
A team led by William Hoppitt of the University of St. Andrews presented wild meerkats with a novel foraging task to investigate the animal’s learning mechanisms. ‘The model deals with the rate at which individuals interact with the task, solve the task once they are interacting with it, or give up on the task when they are manipulating it,’ said Hoppitt.
They found that the meerkats engaged in a wide variety of social and asocial behaviours to learn to solve the task, and that in general the social factors helped draw the meerkats into the task, while the asocial processes helped them actually solve the task.
The model may also be more broadly applicable and can be used to investigate the relationship between social learning mechanisms and so-called ‘behavioural traditions’ that together can constitute a culture.
Next Generation: In Vivo Drug Factories
By Sabrina Richards | August 13, 2012
Researchers use UV light to stimulate protein production in nano-sized delivery capsules in mice.
Nanoparticles expressing a GFP reporter.
Device: Science is one step closer to producing drugs in the right place at the right time in the body, avoiding the collateral damage of untargeted treatments. Researchers led by Daniel Anderson at the Massachusetts Institute of Technology have designed nanoparticles that can be stimulated via UV light to produce proteins on demand in vivo.
The new method, which involves packaging the molecular machinery for making proteins into a membraned capsule, allows the researchers to spatially and temporally regulate protein production, said Zhen Gu, who also researches nanoparticle drug delivery at North Carolina State and University of North Carolina, Chapel Hill, but did not participate in the research. “They can control generation of a protein at any time with a trigger of light.”
The scientists created the nano-sized “protein factories” by using lipids to encapsulate polymerase and other machinery necessary for protein production from E. coli, along with a DNA plasmid containing a gene of interest. To block transcription until the right moment, they added a DNA “photo-labile cage” to the plasmid—a small chemical that inhibits transcription but is cleaved by exposure to UV light.
To test the principle in vivo, the researchers used luciferase as the reporter protein and injected mice with the nanovesicles. After zapping them with UV light at the site of injection, they were able to measure a local burst of luminescence.
What’s new: Protein expression in liposomes has been possible for at least 10 years, said Mitchel Doktycz, a synthetic biologist at Oak Ridge National Laboratory in Tennessee. What is new, said Doktycz, who did not participate in the research, is being able to control the timing of protein expression in an animal. “They can do it remotely,” he said.
And that switch is not limited to UV light, added Gu, but will likely work with other wavelengths using different chemical ligands.
Avi Schroeder
Importance: Many life-saving drugs, such as chemotherapy, can have nasty and toxic effects outside the tissues they’re designed to treat. The goal of remotely-controlled factories like Anderson’s is to produce a drug in a specific place (such as a tumor) at a specific time (after enough particles have accumulated to produce a therapeutic effect). Anderson’s group is “trying to deliver a payload, [and] activate [it] in a specific spot, so they’re not dosing everywhere,” Doktycz explained—which has the potential to minimize side effects while maximizing therapeutic benefit.
Needs improvement: “We have a long way to go still before we have a drug factory that will land in a target tissue to produce a drug of interest,” noted Anderson. The study has proved the principle of the first step—getting the protein expressed on signal—but future research will need to ensure that the nanoparticles and the proteins they produce aren’t toxic in the wrong place, and that they get to the right location. Targeting the nanoparticles to the appropriate tissues might be achieved by “decorating” the surface of the vesicles with specific proteins, said Gu.
Furthermore, although most of the materials in the current particles are probably safe, some are microorganism-derived, Anderson pointed out, and most likely need to be switched to human alternatives. Finally, getting the drug expressed is also just one part of the problem, said Doktycz. So far the system has no way to re-cage the DNA to halt protein production when it’s no longer needed. “Turning on is one thing, but turning off is another,” he said.
(Source: the-scientist.com)
A new study from The University of Queensland shows monitoring the brain of stroke patients using Quantitative EEG (QEEG) studies could inform treatments and therefore, minimising brain damage of stroke victims.
“The main goals of this research were to evaluate key findings, identify common trends and determine what the future priorities should be, both for research and for translating this to best inform clinical management of stroke patients,” Dr Finnigan from UQ’s Centre for Clinical Research said.
The review of outcomes from hundreds of patients has highlighted that QEEG indicators are particularly informative in two ways.
“Firstly they can help predict long-term deficits caused by stroke, … In addition, they could provide immediate information on how patients are responding to treatments and guide decisions about follow-on treatments, even before stroke symptoms change,” Dr Finnigan said.
Scientists have found a way of growing new blood vessels inside the body. They used cells derived from skin, that when injected into a damaged leg in massive numbers, moulded into the shape of a small blood vessel. This improved blood supply to withered muscles, giving them a new lease of life.
The technique, developed at King’s College London, could also be used to repair the damage done by heart attacks. Professor Qingbo Xu, who is funded by the British Heart Foundation, started by taking human skin cells. Using a cocktail of genes and chemicals, he turned them into early-stage blood vessel cells, programmed to form blood vessels.
He then injected half a million of these cells into the hind leg of a mouse whose foot muscles had been damaged due to poor circulation. These formed a small blood vessel that ferried blood to the damaged muscle, allowing it to repair itself, enabling the creature to put some weight on its foot, the journal Proceedings of the National Academy of Sciences reports.
The professor hopes that injected into the heart, the same cells could be used to heal damage done by heart attacks.
A condition believed to be a normal part of the ageing process has been found to have a negative effect on the brain function of older adults.
Leukoaraiosis, also known as small vessel ischemia, is a condition in which diseased blood vessels lead to small areas of damage in the white matter of the brain. The lesions are common in the brains of people over the age of 60, although the amount of disease varies among individuals.
"We know that aging is a risk factor for leukoaraiosis, and we suspect that high blood pressure may also play a role, … Different systems of the brain respond differently to disease, … White matter damage affects connections within the brain’s language network, which leads to an overall reduction in network activity." -Kirk M. Welker, M.D., assistant professor of radiology in the College of Medicine at Mayo Clinic in Rochester, Minn.
(Source: medicalxpress.com)