Scientists help identify possible botulism blocker

Oct. 11, 2013 — U.S. and German scientists have decoded a key molecular gateway for the toxin that causes botulism, pointing the way to treatments that can keep the food-borne poison out of the bloodstream.Study leaders Rongsheng Jin, associate professor of physiology & biophysics at UC Irvine, and Andreas Rummel of the Institute for Toxicology at Germany’s Hannover Medical School created a three-dimensional crystal model of a complex protein compound in the botulinum neurotoxin. This compound binds to the inner lining of the small intestine and allows passage of the toxin into the bloodstream.The 3-D structure — shaped much like the Apollo lunar landing module — let the researchers identify places on the surface of the complex protein that enable it to dock with carbohydrates located on the small intestine’s interior wall. In tests on mice, they found that certain inhibitor molecules blocked the botulism compound from connecting to these sites, which prevented the toxin from entering the bloodstream.Botulinum neurotoxins are produced by Clostridium botulinum and cause the possibly fatal disease botulism, which impedes nerve cells’ ability to communicate with muscles and can lead to paralysis and respiratory failure. The botulinum toxin has also been identified as a potential biological weapon against a civilian population.”Currently, there is no efficient countermeasure for this toxin in case of a large outbreak of botulism,” Jin said. “Our discovery provides a vital first step toward a pharmaceutical intervention at an early point that can limit the toxin’s fatal attack on the human body.”Study results appear online in the open-access journal PLOS Pathogens.Jin added that his work opens the door to further development of preventive treatments for botulism. At the same time, the molecular gateway for the lethal toxin could be exploited for alternative applications, such as the oral delivery of protein-based therapeutics.

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Woman awarded £5,000 for poor dental treatment

Home » No Win No Fee » Latest Personal Injury News » 2013 » 10 » Woman awarded £5,000 for poor dental treatmentWoman awarded £5,000 for poor dental treatmentA woman from Knebworth has been awarded compensation of almost £5,000 after suffering poor dental work.Carole Gavin sued Dr Alykhan Dinani over treatment that was carried out to such a low standard it resulted in her losing a tooth. Ms Gavin had visited the dentist for routine root canal treatment and a crown, but the action taken by the medical expert left one tooth so badly broken and infected that it later had to be removed.The 46-year-old villager told the Hertfordshire Mercury she is not the sort of person who would take legal action on a whim, but she felt the incident was of such severity that she opted to.”I wanted to make people aware of what happened and that there is a recourse. You can’t see inside your own mouth. You don’t know what should be done and you can’t tell if it’s been done correctly,” Ms Gavin said.She had originally visited the practice to see Dr Dinani in May 2008 and described how the crown was fitted poorly. Indeed, she soon found food became lodged under her tooth and this led to an infection and a painful abscess.At this point, she returned to the practice and told how the dentist did not remove the food residue that had gathered beneath the crown. Several weeks later she tried to get another appointment but was soon rushed into A&E.”The left side of my face became extremely swollen and I was in so much pain. I was really concerned so I went straight to my nearest hospital,” she explained.Ms Gavin was informed the tooth could not be repaired because the root canal treatment had been carried out incorrectly. As a result, it was removed.She has now been awarded compensation of £4,875. Dr Dinani and Stevenage Dental Practice chose not to comment.Or call us on 0800 884 0321SHARE THIS

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Panda poop microbes could make biofuels of the future

Sep. 10, 2013 — Unlikely as it may sound, giant pandas Ya Ya and Le Le in the Memphis Zoo are making contributions toward shifting production of biofuels away from corn and other food crops and toward corn cobs, stalks and other non-food plant material.Scientists presented an update today on efforts to mine Ya Ya and Le Le’s assets for substances that could do so during the 246th National Meeting & Exposition of the American Chemical Society (ACS). And if things work out, giant pandas Er Shun and Da Mao in the Toronto Zoo will be joining the quest by making their own contributions.”The giant pandas are contributing their feces,” explained Ashli Brown, Ph.D., who heads the research. “We have discovered microbes in panda feces might actually be a solution to the search for sustainable new sources of energy. It’s amazing that here we have an endangered species that’s almost gone from the planet, yet there’s still so much we have yet to learn from it. That underscores the importance of saving endangered and threatened animals.”Brown and her students, based at Mississippi State University, now have identified more than 40 microbes living in the guts of giant pandas at the Memphis Zoo that could make biofuel production from plant waste easier and cheaper. That research, Brown added, also may provide important new information for keeping giant pandas healthy.Ethanol made from corn is the most common alternative fuel in the U.S. However, it has fostered concerns that wide use of corn, soybeans and other food crops for fuel production may raise food prices or lead to shortages of food.Brown pointed out that corn stalks, corn cobs and other plant material not used for food production would be better sources of ethanol. However, that currently requires special processing to break down the tough lignocellulose material in plant waste and other crops, such as switchgrass, grown specifically for ethanol production. Breaking down this material is costly and requires a pretreatment step using heat and high pressure or acids. …

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Recycled sewage water is safe for crop irrigation, study suggests

Sep. 9, 2013 — The first study under realistic field conditions has found reassuringly low levels of pharmaceuticals and personal care products (PPCPs) in crops irrigated with recycled sewage water, scientists reported in Indianapolis today at the 246th National Meeting & Exposition of the American Chemical Society (ACS).”The levels of pharmaceuticals and personal care products that we found in food crops growing under real-world conditions were quite low and most likely do not pose any health concern,” said Jay Gan, Ph.D., who led the study. “I think this is good news. These substances do not tend to accumulate in vegetables, including tomatoes and lettuce that people often eat raw. We can use that information to promote the use of this treated wastewater for irrigation.”Gan and colleagues at the University of California-Riverside launched the study because drought and water shortages in the American southwest and in other arid parts of the world are using water recycled from municipal sewage treatment plants to irrigate food crops as the only option.Water from toilets and sinks enters those facilities from homes and offices, and undergoes processing to kill disease-causing microbes and remove other material. Processing leaves that water, or “effluent,” from most sewage treatment plants clean enough to drink. Traditionally, however, sewage treatment plants simply discharge the water into rivers or streams. The effluent still may contain traces of impurities, including the remains of ingredients in prescription drugs, anti-bacterial soaps, cosmetics, shampoos and other PPCPs that are flushed down toilets and drains.Gan explained that concerns have arisen about the health and environmental effects of those residual PPCPs, especially over whether they might accumulate to dangerous levels in food crops. Previous studies on PPCPs in food crops were small in scale and conducted in laboratories or greenhouses. Gan said his team was the first to focus on 20 PPCPs in multiple crops under realistic field conditions.They chose eight vegetables that people often eat raw — carrots, bell peppers, tomatoes, cucumbers, lettuce, spinach, celery and cabbage. …

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Climate change will upset vital ocean chemical cycles, research shows

Sep. 8, 2013 — New research from the University of East Anglia shows that rising ocean temperatures will upset natural cycles of carbon dioxide, nitrogen and phosphorus.Plankton plays an important role in the ocean’s carbon cycle by removing half of all CO2 from the atmosphere during photosynthesis and storing it deep under the sea — isolated from the atmosphere for centuries.Findings published today in the journal Nature Climate Change reveal that water temperature has a direct impact on maintaining the delicate plankton ecosystem of our oceans.The new research means that ocean warming will impact plankton, and in turn drive a vicious cycle of climate change.Researchers from UEA’s School of Environmental Sciences and the School of Computing Sciences investigated phytoplankton — microscopic plant-like organisms that rely on photosynthesis to reproduce and grow.Lead researcher Dr Thomas Mock, said: “Phytoplankton, including micro-algae, are responsible for half of the carbon dioxide that is naturally removed from the atmosphere. As well as being vital to climate control, it also creates enough oxygen for every other breath we take, and forms the base of the food chain for fisheries so it is incredibly important for food security.”Previous studies have shown that phytoplankton communities respond to global warming by changes in diversity and productivity. But with our study we show that warmer temperatures directly impact the chemical cycles in plankton, which has not been shown before.”Collaborators from the University of Exeter, who are co-authors of this study, developed computer generated models to create a global ecosystem model that took into account world ocean temperatures, 1.5 million plankton DNA sequences taken from samples, and biochemical data.”We found that temperature plays a critical role in driving the cycling of chemicals in marine micro-algae. It affects these reactions as much as nutrients and light, which was not known before,” said Dr Mock.”Under warmer temperatures, marine micro-algae do not seem to produce as many ribosomes as under lower temperatures. Ribosomes join up the building blocks of proteins in cells. They are rich in phosphorus and if they are being reduced, this will produce higher ratios of nitrogen compared to phosphorus, increasing the demand for nitrogen in the oceans.”This will eventually lead to a greater prevalence of blue-green algae called cyanobacteria which fix atmospheric nitrogen,” he added.

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Human gut microbes alter mouse metabolism, depending on diet

Sep. 5, 2013 — Germ-free mice that received gut bacteria from obese humans put on more weight and accumulated more fat than mice that were given bacteria from the guts of lean humans, according to a new study. This finding, which demonstrates the transmission of physical and metabolic traits via communities of microbes in the gut, depends on the rodents’ diet. And the researchers responsible suggest that it may represent an important step toward developing new personalized probiotic and food-based therapies for the treatment or prevention of obesity.This new research follows on the heels of related studies showing that the variety of microbial genes in one’s gut can influence obesity — and that high-fiber food, such as fruits and vegetables, tends to boost such bacterial diversity. But, this new study shows directly that microbial communities from the gut can transmit lean or obese traits; it also begins to name specific players involved, along with their designated roles and how these roles are tied to the foods we consume. (Bacteroides, for example, which has been observed at increased levels in the microbiota of lean individuals, was found to play a protective role against increased fat accumulation in mice on certain diets.)Vanessa Ridaura, a graduate student at Washington University’s School of Medicine, and colleagues took samples of the microbes that were living in the guts of human fraternal and identical twins. For each pair of twins in the study, one sibling was lean while the other was obese. The researchers then transplanted the discordant twins’ gut microbiota into the guts of germ-free mice that had been raised under sterile conditions, without any microbes of their own.The results of their study are published in the 6 September issue of the journal Science.”The first thing that Vanessa identified in these mice, which were consuming a standard mouse diet, was that the recipients of the obese twins’ microbiota gained more fat than the recipients of the lean twins’ microbiota,” explained Jeffrey Gordon, director for the Center of Genome Sciences and Systems Biology at Washington University School of Medicine and a co-author of the Science report. “This wasn’t attributable to differences in the amount of food they consumed, so there was something in the microbiota that was able to transmit this trait. Our question became: What were the components responsible?”This transplantation of gut microbes from humans to mice led to metabolic changes in the rodents that are associated with obesity in humans. …

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Overgrazing turning parts of Mongolian Steppe into desert

Sep. 5, 2013 — Overgrazing by millions of sheep and goats is the primary cause of degraded land in the Mongolian Steppe, one of the largest remaining grassland ecosystems in the world, Oregon State University researchers say in a new report.Using a new satellite-based vegetation monitoring system, researchers found that about 12 percent of the biomass has disappeared in this country that’s more than twice the size of Texas, and 70 percent of the grassland ecosystem is now considered degraded. The findings were published in Global Change Biology.Overgrazing accounts for about 80 percent of the vegetation loss in recent years, researchers concluded, and reduced precipitation as a result of climatic change accounted for most of the rest. These combined forces have led to desertification as once-productive grasslands are overtaken by the Gobi Desert, expanding rapidly from the south.Since 1990 livestock numbers have almost doubled to 45 million animals, caused in part by the socioeconomic changes linked to the breakup of the former Soviet Union, the report said. High unemployment led many people back to domestic herding.The problem poses serious threats to this ecosystem, researchers say, including soil and water loss, but it may contribute to global climate change as well. Grasslands, depending on their status, can act as either a significant sink or source for atmospheric carbon dioxide.”This is a pretty serious issue,” said Thomas Hilker, an assistant professor in the OSU College of Forestry. “Regionally, this is a huge area in which the land is being degraded and the food supply for local people is being reduced.”Globally, however, all ecosystems have a distinct function in world climate,” he said. “Vegetation cools the landscape and plays an important role for the water and carbon balance, including greenhouse gases.”Even though it was clear that major problems were occurring in Mongolia in the past 20 years, researchers were uncertain whether the underlying cause was overgrazing, climate change or something else. This report indicates that overgrazing is the predominant concern.Mongolia is a semi-arid region with harsh, dry winters and warm, wet summers. About 79 percent of the country is covered by grasslands, and a huge surge in the number of grazing animals occurred during just the past decade — especially sheep and goats that cause more damage than cattle. …

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Canine remote control, using your smart phone? Hands-free dog walking for the digital age

Sep. 3, 2013 — That old “best friend” can get a bit tiresome, all that rolling over, shaking paws, long walks and eating every crumb of food off the floor. But, what if there were a way to command your dog with a remote control, or even via your smart phone…or even without hands?Share This:Jeff Miller and David Bevly of the Department of Mechanical Engineering, at Auburn University, Auburn, Alabama, have devised just such a system and describe details in a forthcoming issue of the International Journal of Modelling, Identification and Control. The device based on a control suite with a microprocessor, wireless radio, GPS receiver, and an attitude and heading reference system provides autonomous guidance of the canine using an embedded command module with vibration and tone generation capabilities. Tests in a structure and non-structured environment show obedience accuracy up to almost 98%. It sounds like a boon for the lazy dog owner.Of course, there is a serious side to the development of such a technology that allows dogs to be given commands remotely and for them to respond consistently. Dogs remain, for instance, the most accurate and sensitive mobile detection system for hidden explosives, people trapped after earthquakes and other disasters and in sniffing out drugs. However, the dog handler in such environments may not be able to safely access the place the dog can reach. Moreover, in a noisy environment or where the dog’s hearing is compromised giving the necessary commands might also be impossible.The team has demonstrated that a search & rescue or other working dog can be trained to respond “virtually flawlessly” to remote control tones and vibrations as if they were immediate commands from a human handler. “The ability to autonomously control a canine has far reaching,” the team says. …

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Antibiotic-resistant strains of Salmonella tracked from farm to fork

Aug. 29, 2013 — Continuing research on Salmonella may enable researchers to identify and track strains of antibiotic resistant bacteria as they evolve and spread, according to researchers in Penn State’s College of Agricultural Sciences.Tracing the transmission of individual strains from agricultural environments to humans through the food system is difficult because of the rapid evolution of resistance patterns in these bacteria. Resistance patterns change so quickly that, until now, it has been impossible to determine where some highly resistant strains are coming from.Michael DiMarzio, a doctoral candidate in food science working under the direction of Edward Dudley, associate professor and Casida Development Professor of Food Science, developed a method for identifying and tracking strains of Salmonella enterica serological variant Typhimurium as they evolve and spread.Every year in the United States, the various strains of Salmonella together are responsible for an estimated 1 million illnesses, 20,000 hospitalizations and 400 deaths at an economic cost exceeding $3 billion. Salmonella Typhimurium accounts for at least 15 percent of clinically reported salmonellosis infections in humans nationally. The number of antibiotic-resistant isolates identified in humans is increasing steadily, suggesting that the spread of antibiotic-resistant strains is a major threat to public health.”Typhimurium infections have exhibited a gradual decline in susceptibility to traditional antibiotics, a trend that is concerning in light of this pathogen’s broad host range and its potential to spread antibiotic resistance determinants to other bacteria,” DiMarzio said. “Now more than ever, it is imperative to effectively monitor the transmission of Salmonella Typhimurium throughout the food system to implement effective control measures.”Building on recent research done in Dudley’s lab, DiMarzio developed the new approach to identify antibiotic resistant strains of Salmonella Typhimurium focusing on virulence genes and novel regions of the bacteria’s DNA known as clustered regularly interspaced short palindromic repeats, or CRISPRs. They report their results in the September issue of Antimicrobial Agents and Chemotherapy.CRISPRs are present in many foodborne pathogens. The researchers demonstrated that CRISPR sequences can be used to identify populations of Salmonella with common antibiotic-resistance patterns in both animals and humans.”Specifically, we were able to use CRISPRs to separate isolates by their propensity for resistance to seven common veterinary and human clinical antibiotics,” DiMarzio said. “Our research demonstrates that CRISPRs are a novel tool for tracing the transmission of antibiotic-resistant Salmonella Typhimurium from farm to fork.”DiMarzio found that several subtypes of Salmonella Typhimurium showed up repeatedly in the frozen collection of Salmonella samples taken from cows, pigs and chickens in Penn State’s Animal Diagnostic Laboratory. In this case, researchers looked at 84 unique Salmonella Typhimurium isolates collected from 2008 to 2011.”We know those strains are widely disbursed, and the thing they have in common is that they have noticeably higher levels of antibiotic resistance,” he said. …

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Parasitic worm genome uncovers potential drug targets

Aug. 28, 2013 — Researchers have identified five enzymes that are essential to the survival of a parasitic worm that infects livestock worldwide and is a great threat to global food security. Two of these proteins are already being studied as potential drug targets against other pathogens.The team sequenced the genome of Haemonchus contortus, or the barber pole worm, a well-studied parasitic worm that resides in the gut of sheep and other livestock globally. This genome could provide a comprehensive understanding of how treatments against parasitic worms work and point to further new treatments and vaccines.The Barber pole worm or H. contortus is part of a family of gastrointestinal worms that are endemic on 100% of farms and are estimated to cost the UK sheep industry alone more than £80 million pounds each year. H. contortus has become resistant to all major treatments against parasitic worms, so its genome is a good model to understand how drug resistance develops in this complex group of closely related parasites and will also reveal further potential drug and vaccine targets.“Our reference genome allows researchers to understand how H. contortus and other worms of this type acquire resistance to a wide range of anthelmintics – the drugs used to treat worm infections,” says Dr James Cotton, senior author from the Wellcome Trust Sanger Institute. “Seeing a common theme of drug resistance in this well-characterised worm is extremely important because both people and animals are reliant on so few treatments against parasitic worms.”The team sequenced the genome of a strain of H contortus that was susceptible to all major classes of drugs against parasitic worms. By comparing this sequence with that of worms that have acquired drug resistance, the researchers expect to reveal a wealth of information about how and why resistance has occurred.“The H. …

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How quickly can a bacterium grow? E. coli can replicate close to thermodynamic limits of efficiency

Aug. 27, 2013 — All living things must obey the laws of physics — including the second law of thermodynamics, which states that the universe’s disorder, or entropy, can only grow. Highly ordered cells and organisms appear to contradict this principle, but they actually do conform because they generate heat that increases the universe’s overall entropy.Still, questions remain: What is the theoretical threshold for how much heat a living cell must generate to fulfill its thermodynamic constraints? And how closely do cells approach that limit?In a recent paper in the Journal of Chemical Physics, MIT physicist Jeremy England mathematically modeled the replication of E. coli bacteria and found that the process is nearly as efficient as possible: E. coli produce at most only about six times more heat than they need to meet the constraints of the second law of thermodynamics.”Given what the bacterium is made of, and given how rapidly it grows, what would be the minimum amount of heat that it would have to exhaust into its surroundings? When you compare that with the amount of heat it’s actually exhausting, they’re roughly on the same scale,” says England, an assistant professor of physics. “It’s relatively close to the maximum efficiency.”England’s approach to modeling biological systems involves statistical mechanics, which calculates the probabilities of different arrangements of atoms or molecules. He focused on the biological process of cell division, through which one cell becomes two. During the 20-minute replication process, a bacterium consumes a great deal of food, rearranges many of its molecules — including DNA and proteins — and then splits into two cells.To calculate the minimum amount of heat a bacterium needs to generate during this process, England decided to investigate the thermodynamics of the reverse process — that is, two cells becoming one. …

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Skin cell defect is surprising allergy trigger: Skin and food allergies can be result of skin cell ‘glue’ deficiency

Aug. 26, 2013 — In a new study published in Nature Genetics, Northwestern Medicine and Tel Aviv University scientists have found that a structural defect in skin cells can contribute to allergy development, including skin and food allergies, traditionally thought primarily to be a dysfunction of the immune system.The finding is related to the team’s identification of a new rare genetic disease, called “severe dermatitis, multiple allergies, and metabolic wasting,” or SAM, caused by mutations in the molecule desmoglein 1.”Desmoglein 1 is best understood as the ‘glue’ that holds the outer layer of human skin together,” said Kathleen Green, Joseph L. Mayberry, Sr., Professor of Pathology and Toxicology at Northwestern University Feinberg School of Medicine. “Historically, the molecule was mainly believed to have a structural role: this adhesion between cells contributes to the physical barrier that regulates water loss and also acts as the body’s major defense against environmental elements. But there are a large number of molecules that form this barrier, distributed in a highly-patterned manner, prompting our team to hypothesize that they do more than just mediate adhesion.”Green’s group at Northwestern worked with an international team that analyzed clinical data from two families, combined with genetic analysis including next-generation DNA sequencing and light and electron microscopy, among other techniques. They found that when desmoglein 1 does not properly function or does not exist, the resulting barrier disruption can affect the immune response, and consequences can be severe.”This work is also significant because it suggests that in addition to impairing the physical barrier, loss of desmoglein 1 may more directly regulate expression of genes that control the immune response and contribute to allergy,” says Green. “Conceptually, it allows us to build on previous studies and make conclusions about the importance of other structural proteins in the skin barrier.”Green notes that the finding, combined with recent published data, could eventually lead investigators to discover further connections between defects in structural molecules and less severe allergies such as atopic dermatitis, eczema and more common food allergies.

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Restricting food and fluids during labor is unwarranted, study suggests

Aug. 22, 2013 — Despite the longstanding, widespread practice of restricting women’s food and fluid intake during labor, a large-scale analysis in The Cochrane Library finds no need for these restrictions and supports women eating and drinking as they please.”There should be no hospital policies which restrict fluids and foods in labor; nor should formal guidelines tell women to take specific foods, such as energy drinks,” states one of the study’s authors, Gillian ML Gyte, M.Phil, of the department of women and children’s health at the University of Liverpool in the U.K.She and her co-authors point out that prior research has shown that many women in labor do not feel like eating, but for others the notion of long hours without any food or drink can be anxiety provoking.In some cultures, women eat and drink as they like during labor both for nourishment and comfort. However, in Western industrialized societies, physicians have often restricted women’s fluid and food intake during labor in case a caesarean section and general anesthesia are necessary later. The restrictions largely grew out of one 1940s study, which showed that during general anesthesia, women run an increased risk of having their stomach contents enter their lungs, which can be dangerous or even life-threatening. But today, caesarean sections are most often performed using regional anesthesia and safer, more modern general anesthesia techniques reduce the risk of aspiration. Women on food and fluid restrictions often do receive ice chips and/or intravenous (IV) fluids but IV fluids themselves come with medical risks.The meta-analysis included five studies with a combined total of 3,130 women; all five involved women considered at low-risk for needing general anesthesia during labor. The analysis was dominated by one large trial involving 2,443 women.For both mothers and newborns, the authors compared the effects of food-and-drink restrictions with no such restrictions. The three primary outcomes reviewed for women were having a caesarean section, having a vaginal birth, and the mother’s satisfaction with the birth. The two primary outcomes reviewed for infants were Apgar scores and blood glucose levels.”Our study found no difference in the outcomes measured, in terms of the babies’ wellbeing or the likelihood of a woman needing a C-section,” said Gyte. “There is no evidence of any benefit to restricting what women eat and drink in labor.” The researchers also emphasize the value of allowing women to make choices regarding these matters.Gargey Patil, M.D., an obstetrician with Florida Hospital in Orlando, said that he would seriously consider applying these new findings in his own care for women in labor, after consulting with anesthesiologist colleagues. …

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Toxic nanoparticles might be entering human food supply

Aug. 22, 2013 — Over the last few years, the use of nanomaterials for water treatment, food packaging, pesticides, cosmetics and other industries has increased. For example, farmers have used silver nanoparticles as a pesticide because of their capability to suppress the growth of harmful organisms. However, a growing concern is that these particles could pose a potential health risk to humans and the environment. In a new study, researchers at the University of Missouri have developed a reliable method for detecting silver nanoparticles in fresh produce and other food products.”More than 1,000 products on the market are nanotechnology-based products,” said Mengshi Lin, associate professor of food science in the MU College of Agriculture, Food and Natural Resources. “This is a concern because we do not know the toxicity of the nanoparticles. Our goal is to detect, identify and quantify these nanoparticles in food and food products and study their toxicity as soon as possible.”Lin and his colleagues, including MU scientists Azlin Mustapha and Bongkosh Vardhanabhuti, studied the residue and penetration of silver nanoparticles on pear skin. First, the scientists immersed the pears in a silver nanoparticle solution similar to pesticide application. The pears were then washed and rinsed repeatedly. Results showed that four days after the treatment and rinsing, silver nanoparticles were still attached to the skin, and the smaller particles were able to penetrate the skin and reach the pear pulp.”The penetration of silver nanoparticles is dangerous to consumers because they have the ability to relocate in the human body after digestion,” Lin said. …

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Hunter-gatherers’ taste for spice revealed

Aug. 22, 2013 — Our early ancestors had a taste for spicy food, new research led by the University of York has revealed.Archaeologists at York, working with colleagues in Denmark, Germany and Spain, have found evidence of the use of spices in cuisine at the transition to agriculture. The researchers discovered traces of garlic mustard on the charred remains of pottery dating back nearly 7,000 years.The silicate remains of garlic mustard (Alliaria petiolata) along with animal and fish residues were discovered through microfossil analysis of carbonised food deposits from pots found at sites in Denmark and Germany. The pottery dated from the Mesolithic-Neolithic transition from hunter-gathering to agriculture.Previously scientists have analysed starches which survive well in carbonised and non-carbonised residues to test for the use of spices in prehistoric cooking. But the new research, which is reported in PLOS ONE, suggests that the recovery of phytoliths — silicate deposits from plants — offers the additional possibility to identify leafy or woody seed material used as spices, not detectable using starch analysis. Phytoliths charred by cooking are more resilient to destruction.Lead researcher Dr Hayley Saul, of the BioArCH research centre at at the University of York, said: “The traditional view is that early Neolithic and pre-Neolithic uses of plants, and the reasons for their cultivation, were primarily driven by energy requirements rather than flavour. As garlic mustard has a strong flavour but little nutritional value, and the phytoliths are found in pots with terrestrial and marine animal residues, our findings are the first direct evidence for the spicing of food in European prehistoric cuisine.”Our evidence suggests a much greater antiquity to the spicing of foods in this region than is evident from the macrofossil record, and challenges the view that plants were exploited by hunter-gatherers and early agriculturalists solely for energy requirements, rather than taste.”The research also involved scientists at the Institució Catalana de Recerca i Estudis Avançats, Institución Milá i Fontanals, Spanish National Research Council, Barcelona, Spain; the Danish Agency for Culture, Copenhagen, Denmark; the Institute of Prehistoric and Protohistoric Archaeology, University of Kiel, Kiel, Germany. And Stiftung Schleswig-Holsteinische Landesmuseen, Schloβ Gottorf, Schleswig, Germany.The research was funded by the UK Arts and Humanities Research Council.

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Food source for whales, seals and penguins at risk: Warming Antarctic seas likely to impact on krill habitats

Aug. 22, 2013 — Antarctic krill are usually less than 6 cm in length but their size belies the major role they play in sustaining much of the life in the Southern Ocean. They are the primary food source for many species of whales, seals, penguins and fish.Krill are known to be sensitive to sea temperature, especially in the areas where they grow as adults. This has prompted scientists to try to understand how they might respond to the effects of further climate change.Using statistical models, a team of researchers from the British Antarctic Survey and Plymouth Marine Laboratory assessed the likely impact of projected temperature increases on the Weddell Sea, Scotia Sea and Southern Drake Passage, which is known for its abundance of krill. This region has experienced sea surface warming of as much as 1°C over fifty years. Projections suggest this could rise by another 1°C by the end of the 21st century.The models are based on equations which link krill growth, sea surface temperature, and food availability. An analysis of the results, published this week in the online journal PLOS ONE, suggests warming, if continued, could reduce the area of growth habitat by up to 20%.In the early life stages krill require deep water with low acidity and a narrow range of temperatures for their eggs to successfully hatch and develop. The larvae then feed on algae on the underside of sea ice.The adults require suitable temperatures and enough of the right type of food (larger phytoplankton) to successfully grow and reproduce. Many of these critical environmental features (temperature, acidity, sea ice and food availability) could be affected by climate change.The projected effects of warming are not evenly spread. The island of South Georgia is located within the area likely to be worst affected. …

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Dams destabilize river food webs: Lessons from the Grand Canyon

Aug. 20, 2013 — Managing fish in human-altered rivers is a challenge because their food webs are sensitive to environmental disturbance. So reports a new study in the journal Ecological Monographs, based on an exhaustive three-year analysis of the Colorado River in Glen and Grand Canyons.Food webs are used to map feeding relationships. By describing the structure of these webs, scientists can predict how plants and animals living in an ecosystem will respond to change. Coauthor Dr. Emma Rosi-Marshall, an aquatic ecologist at the Cary Institute of Ecosystem Studies, comments, “Given the degraded state of the world’s rivers, insight into food webs is essential to conserving endangered animals, improving water quality, and managing productive fisheries.”The project — which relied on a team of more than 10 researchers from the Cary Institute of Ecosystem Studies, Montana State University, Idaho State University, University of Wyoming, U.S. Geological Survey, and Loyola University of Chicago — assessed six sites on the Colorado River, many so remote they required two-week boat trips through the canyon.Study sites were distributed along a 240-mile stretch downstream of Glen Canyon Dam, which was completed in 1963 for water delivery and hydroelectric power needs. During the three-year study, samples of over 3,600 animal diets and 4,200 invertebrate populations were collected and processed. Among the team’s findings: following an experimental flood, sites near the dam had the most dramatic changes in the structure and function of their food webs.Lead author Dr. Wyatt Cross of Montana State University comments, “Glen Canyon Dam has transformed the ecology of the Colorado River. …

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Ecosystems change long before species are lost

Aug. 13, 2013 — Communities in nature are likely to be a lot more sensitive to change than previously thought, according to a new study at Rice University.The study, which appears this week in Nature Communications, shows that scientists concerned about human influence on the biosphere need to take a deeper look at how altering the dynamics of a population — for example, by removing large members of a species through overfishing — can have measurable consequences, said Rice ecologist Volker Rudolf.”Natural communities are increasingly altered through human impact, and ecologists have long strived to determine how these changes influence communities,” Rudolf said. He noted the disappearance of a species is the most extreme but not the only cause of biodiversity loss.”That’s the last thing that happens after you mess up the entire ecosystem for a long period of time,” he said. By then, changes forced upon the structure of a population — such as the ratio of young to old in a species — have already been felt up and down the food chain.Rudolf suspected species play various roles and their effects on the environment change as they progress through their lifecycles, to the degree that altering these life “stages” within a species could have a significant impact. He and Rice graduate student Nick Rasmussen made a considerable effort to prove it.For the painstaking experiments that started in 2009, Rudolf, Rasmussen and their colleagues chose dragonflies and water-diving beetles to represent species that have major impact on their respective communities — in this case, fishless ponds — and then created dozens of miniature environments to analyze that impact. Manipulating the presence of different developmental stages within a predator species in each pond helped the researchers determine that such changes did alter the dynamics of complex ecosystems in a measurable way.”Other than being the largest and most voracious predators in these communities, they’re totally different,” Rudolf said of the apex predators. “We figured if we saw any generalities across these two species, then there’s something to our theory.”They found that altering which classes of size were present in a population also altered the structure of the entire community and ultimately how the whole ecosystem functioned. Also important, Rudolf said, was that changing the structure of populations sometimes had bigger effects on the ecosystem than changing the predator species.The results, he said, “challenge classical assumptions and studies that say we can make predictions by assuming that all individuals of a species are the same. You don’t expect a toddler to do the same thing as a grownup, and the same is the case for animals.”The study could also explain why such human activities as size-selective harvesting can alter the structure of entire food webs in some ocean systems, even when no species had gone extinct and the total biomass of the targeted fish remained the same, he said.”While these changes would be hard to predict by the classical approach, our results suggests such changes are expected when human activities alter the population structure of keystone species in an ecosystem,” Rudolf said. “Thus, natural ecosystems are likely to be much more fragile then we previously thought.”

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Monarch butterflies migration path tracked by generations for first time

Aug. 7, 2013 — Everyone knows all about the epic breeding journey taken each year by generations of monarch butterflies between Mexico and Canada, right? Not so fast, say researchers including University of Guelph biologists.Until now, linking adult butterflies and their birthplaces during a complicated annual migration spanning all of eastern North America and involving up to five generations of the iconic insects had eluded scientists.Now for the first time, researchers have mapped that migration pattern across the continent over an entire breeding season. That information might help conserve a creature increasingly threatened by loss of habitat and food sources, says Tyler Flockhart, a PhD student in U of G’s Department of Integrative Biology.”This tells us where individuals go and where they’re coming from,” he said.Flockhart is lead author of a paper published in the Proceedings of the Royal Society B with Prof. Ryan Norris and co-authors based in Saskatchewan, Colorado and Australia.Their new study traced successive generations of adult monarchs to their birthplaces between the southern United States and Ontario over a single breeding season.Before this, scientists had only a rough idea of those annual colonization patterns, said Prof. Ryan Norris, Integrative Biology. “You could have a monarch showing up in Ontario, but we didn’t know exactly where it came from.”Tracking migration patterns is vital to understanding why monarch numbers are declining and predicting the effects on the insects of milkweed plant loss, habitat destruction and other factors, he said.In 2012, the smallest-ever population of monarchs was recorded in their Mexican overwintering grounds. “They’ve been declining steadily,” said Flockhart.Monarchs normally show up in southern Ontario by June or July. This summer, few had been sighted here by the end of July.The researchers used chemical markers in butterfly wings to match “waves” of insect generations with their birthplaces. Monarch larvae eat only milkweed. …

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Sleep deprivation linked to junk food cravings

Aug. 6, 2013 — A sleepless night makes us more likely to reach for doughnuts or pizza than for whole grains and leafy green vegetables, suggests a new study from UC Berkeley that examines the brain regions that control food choices. The findings shed new light on the link between poor sleep and obesity.Using functional magnetic resonance imaging (fMRI), UC Berkeley researchers scanned the brains of 23 healthy young adults, first after a normal night’s sleep and next, after a sleepless night. They found impaired activity in the sleep-deprived brain’s frontal lobe, which governs complex decision-making, but increased activity in deeper brain centers that respond to rewards. Moreover, the participants favored unhealthy snack and junk foods when they were sleep deprived.”What we have discovered is that high-level brain regions required for complex judgments and decisions become blunted by a lack of sleep, while more primal brain structures that control motivation and desire are amplified,” said Matthew Walker, a UC Berkeley professor of psychology and neuroscience and senior author of the study published Aug. 6 in the journal Nature Communications.Moreover, he added, “high-calorie foods also became significantly more desirable when participants were sleep-deprived. This combination of altered brain activity and decision-making may help explain why people who sleep less also tend to be overweight or obese.”Previous studies have linked poor sleep to greater appetites, particularly for sweet and salty foods, but the latest findings provide a specific brain mechanism explaining why food choices change for the worse following a sleepless night, Walker said.”These results shed light on how the brain becomes impaired by sleep deprivation, leading to the selection of more unhealthy foods and, ultimately, higher rates of obesity,” said Stephanie Greer, a doctoral student in Walker’s Sleep and Neuroimaging Laboratory and lead author of the paper. Another co-author of the study is Andrea Goldstein, also a doctoral student in Walker’s lab.In this newest study, researchers measured brain activity as participants viewed a series of 80 food images that ranged from high-to low-calorie and healthy and unhealthy, and rated their desire for each of the items. As an incentive, they were given the food they most craved after the MRI scan.Food choices presented in the experiment ranged from fruits and vegetables, such as strawberries, apples and carrots, to high-calorie burgers, pizza and doughnuts. The latter are examples of the more popular choices following a sleepless night.On a positive note, Walker said, the findings indicate that “getting enough sleep is one factor that can help promote weight control by priming the brain mechanisms governing appropriate food choices.”

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