Thursday, 06 September 2012 13:56

In mBio This Week: a Rogue’s Gallery of Genomes

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It makes me itchy just thinking about it: the genomes of seven skin-infecting fungi have revealed some surprising facts about these common but little-understood pathogens. The results, published in mBio this week, show these 7 dermatophytes all have one surprising feature that could help explain why athlete’s foot and other fungal skin infections are so very difficult to treat. And why they keep coming back after they’ve apparently been wiped out.
It’s a paradoxical lose-lose for food safety: antibiotic residues in uncured pepperoni or salami meat are potent enough to weaken lactic acid bacteria that processors add to acidify the sausage and make it safe for consumption, but not potent enough to kill off foodborne pathogens like Salmonella or E. coli. The latest from mBio raises some important questions about the safety of my favorite pizza topping, but it also highlights the fact that antibiotic use in livestock can impact food safety in unexpected ways.
Cystic fibrosis (CF) is most often thought of as a disease of the lung, and most microbiome studies of CF patients begin and end with the respiratory tract. But CF also causes profound complications in the gut and pancreas, problems that can seriously impact growth and nutrition. A study in mBio this week treats the lungs and guts of infants with CF as co-evolving ecosystems, comparing and contrasting the ways in which the bacterial communities in these niches evolve and interact.
When the folks at the Steinhart Aquarium in San Francisco were confronted with an outbreak of the mysterious condition called Inclusion Body Disease (IBD) among their boa constrictors and pythons, they knew they needed help.
Swine flu is so three years ago. Should we be concerned about seal flu now?
Recent headlines highlight the alarming rate at which species are being forced into extinction, and amphibians are particularly vulnerable. Up to 41% of frog, toad, newt, salamander, caecilian, and other amphibian species are listed as Vulnerable, Endangered, or Critically Endangered, and although habitat loss and other factors play a role in these extinctions and near-extinctions, it is now clear that a pathogenic fungus is responsible for the threatened state of many amphibian species. Batrachochytrium dendrobatidis, often called chytrid fungus or Bd, causes chytridiomycosis, a disease that strikes entire populations, causing widespread declines that can eventually lead to extinction.
A gene Salmonella picked up from a virus apparently enables it to tweak the human gut to get what it needs to outcompete its neighbors, according to the latest study published in mBio this week.
Why is it that only one strain of MRSA has ever managed to pick up resistance to vancomycin? That's the question asked by the authors of a study in mBio this week. Using comparative genomics, they uncovered what makes the MRSA strain CC5 so proficient at picking up resistance genes and how it is suited to succeed in the hospital setting.
Cryptococcus gattii and C. neoformans are very closely related fungi, but when it comes to the infections they cause there are some important differences. In their study in mBio this week, Ngamskulrungroj et al. drilled down into those differences using a mouse model and found that C. gatii may be a bigger problem for the lungs because it suppresses the immune response there.
Thursday, 03 May 2012 13:09

Treating tumors with anthrax toxin?

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Could anthrax toxin be used to treat tumors? Yes, according to the authors of a study in mBio this week. They altered anthrax toxin to deliver it's potent cargo only to cells that carry a type of receptors that are enriched on several types of tumors. The altered anthrax toxin effectively attached, deposited pore-making proteins in the cell, and shuttled toxic enzymes through the newly made pores.
Many manufacturing processes rely on microorganisms to perform tricky chemical transformations or make substances from simple starting materials. A study published in mBio today describes a way to control a heat-loving archaeon with a temperature switch: it makes a product at low temperatures but not at high temperatures. The authors say the innovation could make it easier to use microorganisms as miniature factories for the production of needed materials like biofuels.
Pared down genomes are the norm in symbiotic microbes, but how do non-symbionts get away with cutting out functions it would appear that they need? The authors of an opinion piece this week explain their ideas about the matter. They say microbes that shed necessary functions may well be getting others to do the hard work for them, an adaptation that can encourage microorganisms to live in cooperative communities.
Bacterial meningitis strikes around 1,000 people in the U.S. every year, according to the CDC, and 10-14% of those cases are fatal. Researchers are drilling down into what happens in the spinal fluid to make a bad case of meningitis and deadly one, but they still know little about the role of one protein involved in the process: a component of the immune system called complement C3. This week, mBio features a study that shows the presence of complement C3 in spinal fluid correlates with survival, a fact that indicates it plays a key role in the pathogenesis of bacterial…
Seasonal flu is serious. Every year, flu kills around 40,000 Americans, but only 30 to 40% of the population gets a flu shot. But what if the annual flu shot wasn't a shot at all? If you could be immunized with a scratchy little pad pressed to your skin, would you be more likely to get that vaccine? We are one step closer to that option thanks to the results of a study in mBio this week, which looked at the immunological reaction to immunization with metal microneedle patches coated with influenza antigens.
A strain of MRSA that humans can contract from livestock most likely became drug resistant due to the use of antibiotics on the farm. That's according to the authors of a study in mBio this week, who looked closely at the genetic relationships among strains of the antibiotic resistant bacterium MRSA (methicillin-resistant Staphylococcus aureus). They discovered that ST398, a type of MRSA found in livestock that can also be passed to humans was originally a human strain, and it developed resistance to antibiotics once it was picked up by farm animals. The finding illustrates a very close link between antibiotic…
Cranberry juice, anyone? Most everyone has had to deal with a urinary tract infection at some point, but as common as the condition is, we still know little about how bacteria progress through the urinary tract. Observations have taught that bacteria may move from the urethra, into the bladder, then up the ureters to the kidneys, leading to kidney infection, or, if the bacteria gain access to the bloodstream, to bacteremia.
Hydrothermal chimneys can be found wherever you have a mid-ocean ridge spreading center. Like geysers on the sea floor, chimneys are formed when hot, mineral-laden sea water emerges from beneath the crust and deposits those minerals in a (sometimes towering) column rich in metals and sulfur. (The one pictured at the right is 9 meters tall.) Microbiologists have studied these chimneys for a while now, examining which bacteria and archaea predominate and what they might be doing while the gushers flow, but a group at the University of Southern California and the University of Minnesota, Twin Cities have taken a…
Individuals with severe autism often suffer from another problem as well: gastrointestinal disturbances. The underlying reason for this apparent link is unknown, but a study in mBio this week reveals that the guts of autistic children differ from other children in at least one important way: many children with autism harbor a genus of bacteria in their guts that non-autistic children do not.
Tuesday, 13 December 2011 11:17

New discovery: how the body fights dengue fever

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We don’t hear a whole lot about dengue fever here in the U.S., but it is a really big problem: worldwide, dengue fever strikes roughly 50 million people every year and takes the lives of thousands, but there are currently no specific treatments and no vaccine to prevent infection with the dengue virus. A study published in mBio this week describes a new discovery about how the body fights the dengue virus, a finding that could explain differences in the ability to fight off the virus and help in developing a drug to boost this response.
Wednesday, 07 December 2011 11:16

Needs-Based Assistance for Outer Membrane Proteins

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How do outer membrane proteins (OMPs) make it from the interior of the cell, through the periplasm, and into the outer membrane? In Pseudomonas aeruginosa, Bam and Lol proteins are big helpers that get some, but not all, OMPs where they need to go. The authors of a study in mBio explain this spotty service may be due to individual differences in the membrane proteins. In short, some folks need the help more than others.