Salmonella's Achilles' heel: Reliance on single food source to stay potent

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Scientists have identified a potential Achilles’ heel for Salmonella – the bacteria’s reliance on a single food source to remain fit in the inflamed intestine.

When these wily bugs can’t access this nutrient, they become 1,000 times less effective at sustaining disease than when they’re fully nourished.

The research suggests that blocking activation of one of five genes that transport the nutrient to Salmonella cells could be a new strategy to fight infection.

“For some reason, Salmonella really wants this nutrient, and if it can’t get this one, it’s in really bad shape,” said Brian Ahmer, associate professor of microbial infection and immunity at The Ohio State University and lead author of the study. “If you could block Salmonella from getting that nutrient, you’d really stop Salmonella.”

The research is published in the journal PLOS Pathogens.

Generally, most of the 42,000 people from the US who report Salmonella infection annually ride out the gastroenteritis symptoms of diarrhea, fever, stomach cramps and vomiting for four to seven days, according to the Centers for Disease Control and Prevention. Antibiotics aren’t a recommended treatment for most infections because they kill good gut bacteria along with Salmonella.

The nutrient needed by Salmonella is composed of a sugar and amino acid stuck together, and is called fructose-asparagine. Its identification alone is also unusual: “It has never been discovered to be a nutrient for any organism,” Ahmer said.

Ahmer and colleagues found this important food source by first identifying the genes that Salmonella requires to stay alive during the active phase of gastroenteritis, when the inflamed gut produces symptoms of infection.

Using a genetic screening technique, the researchers found a cluster of five genes that had to be expressed to keep Salmonella from losing its fitness during gastroenteritis. They then determined that those vital genes work together to transport a nutrient into the bacterial cell and chop up the nutrient so it can be used as food.

The study refers to the pathogen’s fitness because it’s an all-encompassing word for Salmonella survival, growth and ability to inflict damage.

Identifying the nutrient that the genes acted upon was a bit tricky and involved some guessing, Ahmer said. The team realized that the Salmonella genes they found resembled genes in other bacteria with a similar function – transporting the nutrient fructose-lysine into E. coli. But seeing a difference between the genes, the researchers landed, with some luck, on fructose-asparagine.

The researchers ran numerous experiments in cell cultures and mice to observe what happened to Salmonella in the inflamed gut when these genes were mutated. Under differing conditions, Salmonella’s fitness dropped between 100- and 10,000-fold if it could not access fructose-asparagine, even if all of its other food sources were available.

“That was one of the big surprises: that there is only one nutrient source that is so important to Salmonella. For most bacteria, if we get rid of one nutrient acquisition system, they continue to grow on other nutrients,” Ahmer said. “In the gut, Salmonella can obtain hundreds of different nutrients. But without fructose-asparagine, it’s really unfit.”

Because of that sole source for survival, the genes needed for acquisition of this nutrient could be effective drug targets.

“Nobody’s ever looked at nutrient transporters as drug targets because it’s assumed that there will be hundreds more transporters, so it’s a pointless pursuit,” Ahmer said.

This kind of drug also holds promise because it would affect only Salmonella and leave the trillions of other microbes in the gut unaffected.

Ahmer and colleagues are continuing this work to address remaining questions, including the window of time in which access to the nutrient is most important for Salmonella’s survival as well as identifying human foods that contain high concentrations of fructose-asparagine.

A mini-antibody with broad antiviral activity chews up viral DNA and RNA

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3D8 scFv with broad antiviral activity has a unique stereoscopic protection mechanism such as a DNA digestion activity in nucleus and RNA hydrolysis activity in cytoplasm. 3D8 scFv proteins can chew up viral DNA or viral RNA at two different places and stages.

Antibodies and their derivatives can protect plants and animals -- including humans -- against viruses. Members of this class of drugs are usually highly specific against components of a particular virus, and mutations in the virus that change these components can make them ineffective. An article published on June 26th in PLOS Pathogens now reports that a mini antibody called 3D8 scFv can degrade (or chew up) viral DNA and RNA regardless of specific sequences and protect mammalian cells and genetically manipulated mice against different viruses.

Sukchan Lee, from Sungkyunkwan University, Suwon, Korea, and colleagues had previously discovered that 3D8 has both DNase and RNase activity (that is, it can degrade both), and that it can inhibit viruses under certain circumstances. In this study, they genetically manipulated cells and mice to produce 3D8.

They show that when the right amount of 3D8 is produced, the cells and the animals become resistant to two different and normally deadly viruses, namely herpes simplex virus and pseudorabies virus. To protect the animals, it appears critical that the right dose of 3D8 is present in the tissues initially infected by the viruses; once the virus has started to multiply and spread, it seems that 3D8 can no longer contain it efficiently.

When the researchers examined the mechanisms underlying the protective activity, they found that 3D8 fights viruses at two different places and stages of the viral life cycle. In the cell nucleus, it degrades viral DNA to prevent it from getting copied. In the cytoplasm (the area outside of the nucleus), it destroys RNA destined to be used for the production of virus components.

As the researchers discuss, the correct 3D8 dose is critical to destroy only viral DNA and RNA (but not their host genetic material), and additional research is needed to understand the basis for this selective activity. Moreover, to protect the host, 3D8 needs to be present at the time of viral infection and in the right tissues. That said, they conclude that "3D8 scFv is a candidate antiviral protein that can potentially confer resistance to a broad spectrum of animal and plant viruses." They also suggest that "this strategy may facilitate control of...viruses uncharacterized at the molecular level, regardless of their genome type or variations in gene products."

Get insects to bug off this summer

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Summer means an increase in bug and insect activity. How do you know which insects are harmful, what diseases they carry and how to safely avoid them?

"Mosquitoes and ticks are the two pests you primarily want to avoid because they potentially carry infectious diseases," says Jennifer Layden, MD, infectious disease specialist at Loyola University Health System. "Ticks can carry Lyme Disease and Rocky Mountain Spotted Fever and mosquitoes can spread West Nile Virus."

Insect repellents are used to avoid exposure to pests that can bite, attach or burrow into the skin. DEET is the most effective ingredient to protect against biting insects. "Common insect repellent products contain up to 30% DEET for maximum protection," says Christina Hantsch, MD, toxicologist at Loyola. "Products with DEET provide longer duration protection as the concentration of DEET increases."

The longest duration is up to 5 hours for 30% DEET concentration. "Use a product appropriate for the duration of the outdoor activity," advises Hantsch. "I recommend avoiding extended chemical product exposure by changing clothes and washing off insect repellent with soap and water when you come inside."

DEET and other insect repellents such as citronella are generally safe for individuals over 2 months of age. To use a specific product correctly, follow the directions on the package. "Check labels to use a product that is approved by the Environmental Protection Agency as an added measure of safety," says Layden. "I usually recommend that product be reapplied every few hours to maintain effectiveness."

Layden recommends that adults administer insect repellent to children. "Kids can have a difficult time manipulating cans and bottles. You want to avoid inhaling repellent or getting it in mouths or eyes," she says.

Clothing that is pre-treated with repellent is available and remains effective through many washings. "Permethrin-treated fabric is a great option for those who are very active outdoors in the warm months," says Layden. "Treated clothing is safe and approved."

Tips from Dr. Layden on how to avoid bugs this summer are:

• Dusk and dawn are the prime hours for insects

• Wear long sleeves and long pants to cover skin

• Wear light colors which tend to not attract bugs

• Wear loose clothing to avoid skin irritation

"Calamine lotion is effective to take away the annoying itch of a mosquito bite," says Hantsch. For tick removal, use a tweezer as close to the entry of the skin as possible to remove the whole tick. "Clean the bite area with an antiseptic and cover with a loose bandage."

Signs that medical attention is needed include fever, vomiting, excessive sleepiness, swelling, redness and infection.

Noroviruses cause around a fifth of all cases of acute gastroenteritis worldwide

 

June 26, 2014

The Lancet

Noroviruses are a leading cause of acute gastroenteritis (diarrhea and vomiting) across all age groups, responsible for almost one-fifth of all cases worldwide. New estimates highlight the importance of developing norovirus vaccines, say the authors. "Our findings show that norovirus infection contributes substantially to the global burden of acute gastroenteritis, causing both severe and mild cases and across all age groups. Diarrhea remains one of the leading causes of death of children in developing regions of the world."

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Noroviruses are a leading cause of acute gastroenteritis (diarrhea and vomiting) across all age groups, responsible for almost a fifth (18%) of all cases worldwide. New estimates, published in The Lancet Infectious Diseases, highlight the importance of developing norovirus vaccines, say the authors.

"Including data from 48 countries and involving more than 187,000 gastroenteritis cases worldwide, these new estimates are the largest analysis of norovirus infection and disease to date. There has been a proliferation of research on norovirus globally in the last five years, and we harnessed that data for this study," says lead author Dr Benjamin Lopman from the Centers for Disease Control and Prevention in the USA.

"Norovirus spreads from person to person and through contaminated food or water and contact with contaminated surfaces. The virus is so contagious that as few as 18 viral particles may be enough to infect a healthy person, while more than a billion viruses can be found in a single gram of an infected person's stool. Currently, there is no vaccine or treatment for norovirus."

Lopman and colleagues analysed 175 published reports to compile data on the prevalence of norovirus in individuals with acute gastroenteritis between 1990 and 2014. They found that norovirus tended to be more common in cases of acute gastroenteritis in the community (24%) and outpatient (20%) settings than in emergency department visits and hospitalisations (17%), supporting the notion that norovirus is a more common cause of mild disease. However, because of its sheer frequency, norovirus causes a substantial amount of severe disease.

Norovirus was also found in a considerable proportion of cases of acute gastroenteritis cases in both developing countries (14-19%) and developed countries (20%). "This highlights that norovirus, unlike bacterial and parasitic pathogens, cannot be controlled just by improved water and sanitation," explains Lopman.

He concludes, "Our findings show that norovirus infection contributes substantially to the global burden of acute gastroenteritis, causing both severe and mild cases and across all age groups. Diarrhea remains one of the leading causes of death of children in developing regions of the world. We have much to learn about norovirus in those settings, and how it can best be controlled."

Writing in a linked Comment, Dr Ulrich Desselberger and Professor Ian Goodfellow from the University of Cambridge in the UK say, "Inconsistent age stratification across studies prevented an indepth analysis of the burden in people older than 65 years, typically more susceptible to complications and at a greater risk of norovirus-associated death. Furthermore, many countries have not studied the prevalence of noroviruses in sufficient detail to gain reliable burden estimates. Most notably is the paucity of data from Africa where the effect of gastroenteritis probably has more severe consequences. Estimates suggest that 200,000 deaths per year happen in children younger than 5 years of age in developing countries. Therefore, additional high quality studies in these settings will be crucial to improve disease estimates."

World Cup ball plays better at higher altitudes: study

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Brazuca ball in RMIT wind tunnel.

The Brazuca ball being used in the 2014 FIFA World Cup will play better at Brazil's higher altitude stadiums, according to studies by RMIT University researchers in Melbourne, Australia.

Professor Aleksandar Subic and Associate Professor Firoz Alam tested the Brazuca ball in the lead up to the World Cup in the RMIT Aerodynamics Research Wind Tunnel.

The tests found that high altitude will impact on the ball's aerodynamic drag and speed -- players risk overshooting the ball during a long pass, free kick or long shot to the goal post unless they understand the altitude effect and adapt their game accordingly.

The research compared the aerodynamics of the balls specially designed for the last four FIFA World Cups -- Brazuca (2014), Jabulani (2010), Teamgeist (2006) and Fevernova (2002).

"The Brazuca ball will travel much faster than Jabulani and Teamgeist balls at low speeds and it will have more predictable flight in calm wind conditions than its two predecessors," Associate Professor Alam said.

"We found that the Brazuca ball had more aerodynamic resistance at wind speeds between 50 and 70 km/h, compared with the Jabulani ball.

"At 50 to 70 km/h wind speeds, the Jabulani had the lowest aerodynamic resistance of the four.

"At speeds below 50 km/h, the aerodynamic behaviour of Brazuca ball is similar to that of the Fevernova ball."

Professor Subic said the footballs were designed for each World Cup specifically to take advantage of latest technological innovations and the Brazuka was no exception.

"The Brazuka ball has micro-rectangular pimples in a wavy pattern on its surface along with wide and deep seam between the panels, and the seam is almost 40 per cent larger than the length of a Jabulani ball," he said.

"These wide seams generate turbulent airflow creating less aerodynamic drag -- or resistance -- at low speeds, compared with the Jabulani and Teamgeist balls."

Notorious pathogen forms slimy 'streamers' to clog up medical devices

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A group of researchers from the US has moved a step closer to preventing infections of the common hospital pathogen, Staphylococcus aureus, by revealing the mechanisms that allow the bacteria to rapidly clog up medical devices.

In a study published today, 27 June, in the Institute of Physics and German Physical Society's New Journal of Physics, the researchers have shown that the bacteria colonizes into large groups, called biofilms, using a biological glue, and form thin, slimy, thread-like structures called streamers.

The streamers adhere to a surface and are able to trap passing cells as they flow through medical devices such as stents and catheters, becoming more rigid and eventually clogging up the whole device.

In their study, the researchers, from Princeton University, recreated the physical environments of medical devices with curvy channels, multiple networks and a flowing fluid, and showed that streamers can rapidly expand and create a blockage in a surprisingly short space of time.

Moreover, if the surfaces were coated with human blood plasma, which the bacteria often encounter in infectious sites, the biofilm streamers appeared in the structures even more quickly.

Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious strain of the bacteria that has developed a resistance to antibiotics, making it particularly difficult to treat in humans.

MRSA is the most widespread cause of hospital-associated infections in the US and Europe, and has a high mortality rate. Patients with open wounds, implanted devices and weakened immune systems are at the greatest risk of infection.

Infections that are associated with medical devices are a primary concern, as the biofilms that the bacteria form have an enhanced resistance to antibiotics.

Co-author of the research Professor Howard Stone, from Princeton University, said: "We have shown that Staphylococcus aureus can create slimy, thread-like biofilm streamers in environments that mimic the physical and chemical conditions of medical devices such as stents and catheters.

"By studying the morphologies and growth dynamics of the bacteria, we believe there is potential to develop novel methods that prevent diseases associated with this notorious pathogen."

In their study, Professor Stone and colleagues investigated how surface geometry, surface chemistry, and fluid flow affected the formation of streamers.

They examined four strains of Staphylococcus aureus by staining the cells with fluorescent dyes and taking high-resolution images as a flow was passed through the microfluidic structures, which contained curvy channels and multiple networks.

Their results showed that the flow of fluid through the structures was the major contributor to the shape of the biofilm streamers, as opposed to movements of the cells themselves, and that the biofilm streamers could form in a number of different complex environments, leading the researchers to believe that the streamers are ubiquitous in natural environments.

Compared to another common pathogen, Pseudomonas aeruginosa, which the researchers previously studied, Staphylococcus aureus formed and clogged up the channels much more quickly.

"The different dynamics of biofilm formation may result from different mechanisms, and different flows of the biofilm matrix, which are research directions we are currently pursuing," Professor Stone continued.

New theory on cause of ice age 2.6 million years ago

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Researchers analysed deposits of wind-blown dust in northern China to reconstruct monsoon and temperature patterns.

New research in the journal Nature's Scientific Reports has provided a major new theory on the cause of the ice age that covered large parts of the Northern Hemisphere 2.6 million years ago.

The study, co-authored by Dr Thomas Stevens, from the Department of Geography at Royal Holloway, University of London, found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused major ice sheet growth across the Northern Hemisphere.

The change in salinity encouraged sea ice to form which in turn created a change in wind patterns, leading to intensified monsoons. These provided moisture that caused an increase in snowfall and the growth of major ice sheets, some of which reached 3km thick.

The team of researchers analyzed deposits of wind-blown dust called red clay that accumulated between six million and two and a half million years ago in north central China, adjacent to the Tibetan plateau, and used them to reconstruct changing monsoon precipitation and temperature.

"Until now, the cause of the Quaternary ice age had been a hotly debated topic," said Dr Stevens. "Our findings suggest a significant link between ice sheet growth, the monsoon and the closing of the Panama Seaway, as North and South America drifted closer together. This provides us with a major new theory on the origins of the ice age, and ultimately our current climate system."

Surprisingly, the researchers found there was a strengthening of the monsoon during global cooling, instead of the intense rainfall normally associated with warmer climates.

Dr Stevens added: "This led us to discover a previously unknown interaction between plate tectonic movements in the Americas and dramatic changes in global temperature. The intensified monsoons created a positive feedback cycle, promoting more global cooling, more sea ice and even stronger precipitation, culminating in the spread of huge glaciers across the Northern Hemisphere."

Radioactive kitty litter may have ruined our best hope to store nuclear waste

 

Some of the most dangerous nuclear waste in the US is currently scattered between 77 locations all over the country, awaiting permanent storage. Until February, many experts suggested that the best place to put it was a facility about 40 miles east of Carlsbad, New Mexico, called the Waste Isolation Pilot Plant (WIPP). For 15 years, WIPP has operated as the first and only permanent, deep geologic nuclear waste storage facility in the country, holding "low level" radioactive materials — mostly clothing and tools exposed to radiation from nuclear weapons production — in steel barrels more than 2,150 feet below the Earth’s surface.

But earlier this year two emergencies brought that suggestion — and WIPP’s future — into question. And now it seems kitty litter may be to blame.

 

What happened?

WIPP is in a salt desert, and much of the work there involves burrowing through the salt and using huge elevators to deposit the stuff at surface level. The resulting underground caverns are then filled with radioactive waste and eventually closed shut, sealed forever.

Investigators search for a radiation leak at the Waste Isolation Pilot Plant in Carlsbad, NM. (Department of Energy)

In February, according to a press release from the US Department of Energy — which oversees operations at WIPP — two things happened to stall that relatively simple process.

First, on February 5th, a salt-hauling truck caught fire. That would be an inconvenience on the side of a highway, but in an enclosed salt cavern surrounded by nuclear waste, it’s a potential catastrophe. Workers evacuated the site. Fortunately no one was hurt. But the fire was significant enough to shut down underground operations until investigators could figure out what happened and how to stop it from happening again. Surface-level operations continued.

But not for long. Nine days later, late at night on Valentine’s Day, an alarm sounded, indicating that radioactivity was present in the air underground. No one was below ground at the time, but employees on the surface activated massive fans designed to ventilate the underground air. The next day, another monitor went off — this one on the surface — indicating airborne radiation. Employees who worked outside on the surface were told to take shelter inside buildings completely separated from storage operations. Valves allowing air to flow underground were sealed with high-density expanding foam. Everything came to a standstill, indefinitely.

 

Fallout

There are no indications that anyone has been injured from the radiation leak. (All employees went through examinations for radiation exposure; a DOE press release says most workers were not affected, and those who were "received less exposure than a person receives from a chest X-ray.") But for months, nothing has changed. The standstill remains. WIPP’s 850 or so employees are mainly sitting around, waiting (or "performing surface facilities maintenance or assisting with procedure reviews and revisions") while investigators from the US Department of Energy (DOE), the New Mexico Environment Department and elsewhere attempt to figure out what happened.

Initially, there were two hypotheses. The first was that something had gone wrong with the supports inside the cavern where waste was being stored. If that were the case, it meant a piece of salt rock or a steel support had fallen into one of the sealed barrels, puncturing it and releasing radiation into the air.

"That was an unlikely possibility," says Norbert T. Rempe, PhD, a retired geologist who spent decades as a principal engineer at WIPP. The cavern where the radiation monitor went off had been dug only recently, so the chances that supports had eroded or collapsed were probably slim.

Organic kitty litter likely caused a steel barrel's seal to puncture at the Waste Isolation Pilot Plant in Carlsbad, NM. The damage and the resulting radiation leak could close the facility, experts say. (Department of Energy)

More likely, he said, was the second hypothesis: that something had gone awry inside one of the radioactive containers — that the radioactive material had become hot for some reason, expanding and puncturing a steel barrel from the inside.

Last month, DOE investigators went into the cavern. Pictures showed that the latter hypothesis was true; a waste container’s lid was unsealed, and dust around the lid had turned yellow from the unusual heat emanating from inside. Each barrel is labeled to track where it came from. The punctured barrel originated from Los Alamos National Labs.

Jim Conca, PhD, a geologist who worked for years at WIPP who now blogs at Forbes about energy issues, believes he knows what blew the lid off at least one of WIPP’s radioactive barrels. The culprit, he wrote, was kitty litter.

"When someone decides to deviate, that is a bad, bad thing."

As Conca explains it, inorganic cat litter has properties that make it ideal for stabilizing nitrates in radioactive material — for ensuring that it doesn’t dry out and become dangerously hot. So kitty litter is often mixed in barrels with the low-level waste that’s eventually sent to WIPP. What happened at WIPP, he believes, is that one of the radioactive shipments was mixed with organic instead of inorganic material. "‘Green’ cat litter," he writes, is "made with materials like wheat or corn. These organic litters do not have the silicate properties needed to chemically stabilize nitrate the correct way." The result: "solutions can ignite when they dry out."

In other words, the whole problem at WIPP — the radiation leak, the months-long stall in operations, the worries over safety — results from one person’s mess up. (Yesterday, a DOE press release confirmed that kitty litter "may have caused a chemical reaction" that lead to the leak.)

"Everything nuclear is proceduralized," he tells The Verge. "It’s well laid out and everything everyone does is supposed to go up and down the chain of command. When you decide on a procedure for doing something like treating this waste, you don’t deviate from it. Ever. And when someone decides to deviate, that is a bad, bad thing."

He continues: "In this case, it could shut down the most successful nuclear repository in history."

 

Moving forward

Apart from the absurdity in a multibillion-dollar project halted by the decision to use off-brand kitty litter, the real lesson here may lie in the fragility of even the best nuclear storage facility. Corrective action at WIPP could be a massive undertaking. How many other barrels contain the dangerous organic cat litter? Are all of those barrels underground at WIPP? Are they awaiting shipment at surface level in places like Los Alamos? Or are they located at the temporary storage site in Andrews, Texas, where some containers were transferred when problems arose at WIPP?

"Expert assessment will be needed," writes Per Peterson, a professor and researcher at UC Berkeley’s Department of Nuclear Engineering, in an email shared with The Verge, to merely "determine whether the safety benefits of stabilizing or repackaging the material in these drums are justified by the risk to personnel who would attempt to do this work."

And if the DOE decides stabilizing or repackaging the material is unjustified, that would close WIPP for good.

"If that happened, it would be a shame and a disaster — particularly for taxpayers," says the retired WIPP geologist Rempe. The DOE estimates the total cost of the WIPP plant to be $7.2 billion.

Even if WIPP does begin operating again, "we have no idea how long this will take until WIPP is back to normal operations, or what the new normal operations will be," Rempe says. "No one knows right now. And it could be a long time before anyone knows."

'Land grabbing' could help feed at least 300 million people

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Crops grown on "land-grabbed" areas in developing countries could have the potential to feed an extra 100 million people worldwide, a new study has shown.

The improved infrastructure brought about by foreign investment could increase the productivity of subsistence farmlands in countries such as Indonesia and Papua New Guinea and could mean these lands can feed at least 300 million people around the world. This is compared to about 190 million people that could be fed if the land was left tended to by the local population.

The findings have been published today, 27 June, in IOP Publishing's journal Environmental Research Letters.

The large-scale acquisition of land by foreign governments and business -- more commonly known as land grabbing -- is a contentious issue, particularly in Africa where a large number of deals have taken place in regions facing food security problems and malnutrition.

Some argue that investment by foreign governments and business will drastically improve crop yields, generate new jobs and bring new knowledge and infrastructure to often deprived areas. Others highlight the fact that any food grown is often exported to other regions and argue that such deals can strip local communities of their land, water and natural resources, leaving them in a far worse state.

In their study, the researchers, from the Politecnico di Milano, Italy, and University of Virginia, US, quantified the maximum amount of food that could be produced from crops grown on acquired lands and the number of people that this could feed. They also compared the use of traditional farming techniques to industrialised agricultural methods, to come up with the yield gap.

To arrive at their results, the researchers used a unique dataset of all land deals, greater than 200 hectares, which had occurred after 2000. Each land deal included information regarding the spatial extent of the acquired land, the dominant crop, and whether a deal was concluded with a signed or oral contract, or just intended with an expression of interest.

The researchers calculated the potential maximum crop yield from each of these deals and then used the crop's food calories to determine the amount of people it could feed.

If all of the acquired lands were farmed to their full capacity -- a 100% closure of the yield gap -- there would be a 308 per cent increase in rice production, a 280 per cent increase in maize production, a 148 per cent increase in sugar cane production, and a 130 per cent increase in oil palm production, the researchers calculated.

Taking into account the proportion of crops that can be used for food production, as well as the amount needed for a "balanced diet," the results showed that between 300 and 550 million people could be fed by crops grown in the acquired land, compared with between 190 and 370 million people that could be fed if the local community used the land without making major investments.

The results also revealed that the most targeted countries for land grabs are Indonesia, Malaysia, Papua New Guinea and the former Sudan. Altogether, these nations account for around 82 per cent of the total food calories that can be produced by acquired croplands worldwide.

It has been reported in previous studies that around 32.9 million hectares of land have been acquired by large-scale international investors for different purposes. A total of 22 million hectares were acquired for agriculture.

The authors, Maria Cristina Rulli from Politecnico di Milano and Paolo D'Odorico from University of Virginia, said: "Our study has provided a comprehensive assessment of the amount of food that can potentially be produced in land acquired by foreign investors in countries such as Sudan and Indonesia."

Accordingly, "Policy makers need to be aware that if this food were used to feed the local populations it would be sufficient to abate malnourishment in each of these countries even without investments aiming at the closure of the yield gap. Such investments would lead to substantial improvements in crop yields mainly in African countries.

"At the moment there are still open questions which would help inform the debate over what happens to acquired land such as, what happens to food produced? Is it shipped abroad? Were these lands already used for agriculture prior to the acquisition, and (if so) for the cultivation of what crops? With what yields? Answers to these questions would allow us to quantify the decrease in food available to the local communities, and come up with management strategies to mitigate possible negative impacts on the local communities of large scale land acquisition."

Some dogs and cats prone to sunburn: How to protect your animal from skin damage

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White cats are particularly sensitive to the sun. Skin damage to the nose is often not identified as sunburn.

Excessive sunbathing damages the skin. Humans are not the only ones who need to monitor their exposure to UV rays: animals are at risk too. Dogs and cats with white or thin coats are at particular risk, as are animals with very closely shorn fur or with certain pre-existing conditions. Dermatologist Christa Horvath-Ungerböck from the University of Veterinary Medicine, Vienna explains which animals are particularly sensitive, how to prevent sun damage to the skin, and how to treat a sunburned animal.

Human or animals skin with little or no pigmentation is very sensitive to the sun in general. Hairless pets or pets with very short or thin fur can also be vulnerable. For dogs and cats this applies in particular to those parts of the skin that are regularly exposed to the sun. These include the ears, the bridge of the nose, the skin around the eyes, and the back. “Some animals particularly enjoy lying on their backs to bask in the sun. This exposes the skin on their bellies, which is often hairless, to the rays of the sun, increasing the risk of sunburn,” reports veterinary dermatologist Christa Horvath-Ungerböck.

Particularly vulnerable pets

House pets with white or short fur are at particular risk of sunburn. The Dogo Argentino breed, white bulldogs, Dalmatians, boxers, whippets, beagles and white or multi-coloured cats with white patches have skin that is very sensitive to light, especially on their heads. In summer animals with shorn fur can also have a problem. The short hair allows UV rays penetrate down to the sensitive skin and cause sunburn.

Hairless dogs and cats are naturally more sensitive to the sun, since they lack the natural sun protection fur affords. Here too though, skin pigmentation plays a role, and darker animals are less vulnerable to UV rays. Owners of vulnerable breeds should take particular care to protect their animals from the sun.

Sun protection for animals

“As a rule, animals should have a shady place to lie in. Especially at midday, when the sun is at its strongest and presents the greatest risk, not just for the skin but for the animal overall”, explains dermatologist Horvath-Ungerböck. Particularly sensitive animals require sun protection in the form of a waterproof sunscreen with an SPF of at least 30 or a sunblock containing zinc oxide, for example. 

For longer hikes through the mountains where the sun’s rays are particularly aggressive, sensitive animals should wear a t-shirt, coat or hat for protection.

The skin specialist advises owners not to worry: “Not every white dog or white cat needs sunscreen or clothing to protect it from the sun. If sun damage has already occurred though, or if an animal is highly sensitive, it is up to us to protect it from further damage.”

Treating sunburn in animals

If sunburn is visible as reddened, warm or flaking skin, the animal should be moved to the shade as quickly as possible. Cool compresses and ointments to soothe the skin can help relieve the initial symptoms. If the burn is severe, a veterinarian should be consulted as treatment with a cortisone product may be indicated to prevent inflammation. If the skin changes present as a secondary infection, antibiotics may be indicated. The affected animal will need to be well protected from the sun in future to prevent permanent damage.

Certain pre-existing conditions can increase skin sensitivity

Some illnesses and genetic defects that result in a thin coat can make the skin more sensitive to sunburn. Any longer-term stimulus that results in a loss of fur is a possible factor. These can include parasitic infections, chronic skin conditions, or congenital hairlessness.  In some cases, exposure to the sun can worsen an existing condition. Animals with autoimmune skin diseases must be carefully protected from the sun, for example. And areas of the skin that were covered by fur but are suddenly exposed due to hair loss, such as scar tissue after an operation or injury, should be carefully observed and shielded as needed.

Damage caused by sun exposure

In animals, sunburn results in an acute inflammation of the skin that can cause itching or even pain, depending on the individual animal. Frequent sunburns can lead to pre-cancerous conditions or even actual skin tumours. “We sometimes see squamous cell carcinoma on the heads of white, outdoor cats as the result of chronic sun exposure. The affected areas of the skin then need to be surgically removed,” Horvath-Ungerböck explains.

Scientists identify new microbes linked to severe diarrhea

 

June 27, 2014

University of Maryland

Diarrhea is a major cause of childhood mortality in developing countries and ranks as one of the top four causes of death among young children in sub-Saharan Africa and South Asia. In a finding that may one day help control diarrhea, researchers have identified microorganisms that may trigger diarrheal disease and others that may protect against it. These microbes were not widely linked to the condition previously.

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Mihai Pop, an associate professor of computer science at the University of Maryland, recently concluded a major study of diarrheal pathogens in young children from low-income countries.

In a finding that may one day help control a major cause of death among children in developing countries, a team of researchers led by faculty from the University of Maryland, College Park and the University of Maryland School of Medicine has identified microorganisms that may trigger diarrheal disease and others that may protect against it. These microbes were not widely linked to the condition previously.

"We were able to identify interactions between microbiota that were not previously observed, and we think that some of those interactions may actually help prevent the onset of severe diarrhea," says O. Colin Stine, a professor of epidemiology and public health at the University of Maryland School of Medicine.

A much better understanding of these interactions is important, Stine adds, as they could lead to possible dietary interventions. Moderate to severe diarrhea (MSD) is a major cause of childhood mortality in developing countries and ranks as one of the top four causes of death among young children in sub-Saharan Africa and South Asia.

Stine and Mihai Pop, an associate professor of computer science at the University of Maryland, College Park led the six-year project funded by $10.1 million from the Bill & Melinda Gates Foundation. The research results are available in a paper published in the journal Genome Biology.

The researchers used a technique called high-throughput 16S rRNA genomic sequencing to examine both "good" and "bad" microbiota -- the tens of trillions of microbes that inhabit the human intestinal system -- in samples taken from 992 children in Bangladesh, The Gambia, Kenya and Mali under the age of 5 who were suffering from MSD.

The researchers identified statistically significant disease associations with several organisms already implicated in diarrheal disease, such as members of the Escherichia/Shigella genus and Campylobacter jejuni. They also found that organisms not widely believed to cause the disease, including Streptococcus and Granulicatella, correlated with the condition in their study. In addition, the study revealed that the Prevotella genus and Lactobacillus ruminis may play a protective role against diarrhea.

The project is an offshoot of a $20 million study commissioned by the Gates Foundation in 2006. The Global Enterics Multicenter Study (GEMS) was launched in response to unanswered questions surrounding the burden and etiology of childhood diarrhea in developing countries.

GEMS collected troves of useful data on MSD, yet there were still some uncertainties, says Pop, who also has an appointment in the University of Maryland Institute for Advanced Computer Studies.

For example, in almost 50 percent of the children examined with diarrhea, the condition could not be attributed to a specific causal pathogen. The GEMS research also found numerous children carrying Shigella, which is known to cause problems, yet the children showed no signs of MSD.

The Gates Foundation contacted the two University of Maryland scientists in 2007, looking for new analyses of the GEMS data via a combination of computational biology, epidemiology and public health.

"New technologies have opened up new windows of discovery, so they asked us to look at the samples," says Pop, who adds that he and Stine expect to conduct further genomic and epidemiological studies to assess the potential development of diet- or microbiological-based therapeutics.

Adding sugar to high-fat Western diet could be worse than high-fat diet alone

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A high-fructose, high-fat diet can cause harmful effects to the livers of adult rats, according to new research published in Experimental Physiology, providing new insight into the effects of adding fructose to a Western diet high in fat.

The study showed that short-term consumption of a Western diet, rich in saturated fats and fructose, is more damaging for healthy liver development than following a high fat diet alone.

Dr Susanna Iossa, who led the study at the University of Naples, Italy, said:

"This result points to the harmful effect of adding fructose to the usual western, high-fat diet and, together with other related findings, should stimulate the discussion on the use of fructose and fructose-containing sweeteners in beverages and packaged foods.

We performed the research by using an animal model of adult sedentary humans, consisting of adult rats, that were fed for two weeks with either a low-fat diet, a high-fat diet or a diet rich in fat and fructose. This latter diet is very similar in composition to the diet consumed by the large majority of the Western population. After the diet period, we evaluated liver function and we found that the presence of fructose in the high-fat diet exacerbated the impairment of this important metabolic organ, by increasing the build-up of fat in the liver, and decreasing liver insulin sensitivity.

"Much more research should be undertaken in the future, especially regarding the impact of the high-fat high-fructose diet on other metabolically important organs, in order to establish the real impact of this unhealthy dietary habit on health and well-being."

Climate change and the ecology of fear

 

June 27, 2014

Northeastern University College of Science

Climate change is predicted to have major impacts on the many species that call our rocky shorelines home. Indeed, species living in these intertidal habitats, which spend half their day exposed to air and the other half submerged by water, may be subjected to a double whammy as both air and water temperatures rise. Given the reliance of human society on nearshore coastal ecosystems, it is critical that we better understand how climate change will affect them.

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A state-​​of-​​the-​​art heating and cooling system holds the water and air tem­per­a­ture in Trussell’s exper­i­mental habi­tats at exactly 2.5 degrees Cel­sius above the cur­rent tem­per­a­tures in Nahant bay.

Fear isn't just a human emotion -- it's also a pow­erful eco­log­ical phe­nom­enon. Geoff Trussell, pro­fessor and director of Northeastern's Marine Sci­ence Center in Nahant, Mass­a­chu­setts, has been studying the ecology of fear since he first came to the uni­ver­sity back in 2002.

He's dis­cov­ered some sur­prising things: When prey living in the inter­tidal zone sense a predator nearby, they are much less effi­cient at con­verting energy into growth. They pro­duce so much ner­vous energy in the form of ele­vated metab­o­lism, stress hor­mones, heat-​​shock pro­teins, and antiox­i­dant enzymes that there isn't a lot left over to build new tissues.

Trussell, who is chair of the Depart­ment of Marine and Envi­ron­mental Sci­ences, believes this fact can be a crit­ical driver for deter­mining how an overall ecosystem will fare. Resources and predator abun­dance will always fluc­tuate, but it's how the middle species deal with those fluc­tu­a­tions that deter­mines the way the whole system will respond. As he explained, "It's that species in the middle that have to trade off their need to feed with the risk of being eaten by a predator that's ulti­mately going to shape how the system behaves."

But there's one thing that's been missing from this cal­culus: the role of cli­mate change. Some studies have exam­ined how cli­mate change inter­acts with fear, Trussell said, but most of them haven't been very real­istic. The problem, he explained, is that they all imagine a con­stantly ele­vated tem­per­a­ture based on cli­mate change pro­jec­tions put forth by the Inter­gov­ern­mental Panel on Cli­mate Change. They don't account for nat­ural cli­mate vari­a­tion seen on a local scale.

"If you bake any­thing under a high tem­per­a­ture all the time, you're going to get an impact," Trussell said. So in new research pub­lished in the journal Global Change Biology, Trussell and his team took a dif­ferent approach. The researchers built a state-​​of-​​the-​​art system that allows them to con­stantly adjust the water and air tem­per­a­tures in their exper­i­mental habi­tats, holding them 2.5 degrees Cel­sius above actual tem­per­a­ture that is con­tin­u­ously mea­sured in Nahant.

The con­ser­v­a­tive nature of their approach makes their striking results even more sig­nif­i­cant, Trussell said. They found that when a prey species, in this case a snail called Nucella Lapillus, sensed the chem­ical cues of a predator, the inva­sive green crab, it ate fewer mus­sels and thus as expected expe­ri­enced less growth.

But when the team intro­duced the warming sce­nario, that effect was even more pro­nounced. Despite eating just as many mus­sels as in the non-​​warming sce­nario, the snails actu­ally lost weight under the warming conditions.

"You've got these ani­mals that are already burning a lot of energy because they're wor­ried about get­ting eaten," Trussell explained. "And then you throw on top of that the stress that's imposed by tem­per­a­ture increases and even­tu­ally what you end up seeing is that the ani­mals struggle to make a living."

The com­bined effects of pre­da­tion risk and warming seem to create even bigger chal­lenges for these middle species, which Trussell believes are inte­gral to the overall health of an ecosystem. The results, he said, sug­gest that the impacts of cli­mate change may be most sig­nif­i­cant in areas where the fear of being eaten is par­tic­u­larly impor­tant to com­mu­nity dynamics.

"Very rarely are species out there in iso­la­tion just dealing with tem­per­a­ture and its poten­tial increases. They're inter­acting with other species as well and all the chal­lenges that they present, Trussell said. "So looking at how cli­mate is impacting these inter­acting species is what we really need to do if we're going to under­stand the eco­log­ical con­se­quences of cli­mate change.