mBiosphere

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.
Thursday, 01 December 2011 11:16

mBio Study: New compound to control Listeria

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Cantaloupe contaminated with the bacterium Listeria monocytogenes killed 29 people in the U.S. this year in the deadliest foodborne outbreak since 1924, but the pathogen usually strikes in less public ways, quietly sickening an average of 1,600 people per year, according to the CDC. The authors of a study in mBio this week screened 57,000 small molecules to find one compound that can stop Listeria in its tracks. This needle-in-the-haystack approach has turned up a compound that could lead to novel therapeutics for listeriosis and other infections.
Antibiotics: they’re not just for curing the sick. Livestock farms in the U.S. regularly use antibiotic drugs as feed additives to boost animal growth, but a study in mBio this week reveals new evidence that adding antibiotics to pig feed stimulates gene exchange in the guts of these animals, a development that could move antibiotic resistance genes where they’re not wanted.
A parasite of animals (most notably cats) and humans alike, Toxoplasma gondii can boast a global distribution. But it’s not exactly the same organism the world over: one clonal type predominates in Europe and North America and another leads the pack in South America. One thing they do have in common is a chromosome called Chrla, which appears to interact with a major T. gondii virulence factor. Chrla is present in T. gondii isolates from all these regions. So, even though T. gondii from North America and Europe has many marked differences from South American isolates, you can still find…
Antibiotic-resistant enterococci are a serious problem for patients in the hospital, but little is known about how these bacteria are able to escape antibiotics. In mBio this week, Kristich et al. lay out some new discoveries about the ways in which enterococci turn their resistance to cephalosporin antibiotics on and off. The new details could lead to new therapies for preventing and treating enterococcal infections.
Antivirulence drugs disarm pathogens rather than kill them, and although they could be effective in theory, antivirulence drugs have never been tested in humans. A new study to in mBio this week reveals these drugs have the potential to fight infection while avoiding the pitfalls of drug resistance.
It may hardly seem like news, but here’s the latest: raw sewage is loaded with viruses. That’s the part you may have already guessed. The more astounding aspect of a study published in mBio this week is the diversity those viruses represent. Biologists have described only a few thousand different viruses so far, but this latest study reveals that raw sewage is home to the most diverse array of viruses ever found. Apparently, a vast world of unseen viral diversity exists right under our noses.
Neisseria gonorrhoeae, the bacterium behind “the clap”, has several tools in its shed to help it evade antibiotics. One such tool is the multidrug efflux pump MtrC-MtrD-MtrE, which shuttles low concentrations of antimicrobials out of the cell before they can take their toxic toll. In mBio this week, researchers describe a single point mutation that enables N. gonorrhoeae to dramatically increase production of this efflux pump without touching the promoters or repressors that normally control its manufacture.
Why did so many of the people who died from the new strain of H1N1 influenza that broke out in 2009 also have pneumonia? The authors of a study in mBio this week found out how the two infections, pandemic flu and pneumonia, interact to make to make a lethal combination: infection with the pandemic strain of flu caused more extensive damage to the lung epithelium than seasonal flu. The damage requires more extensive tissue repair and opens the body up to attack from bacterial invaders like Streptococcus pneumoniae.
The current vaccines for pneumococcal disease have succeeded in some ways and failed in others, and we still have a lot to learn about vaccine-mediated protection. A study out in mBio this week reveals that some antibodies instigate a Greek tragedy among pneumococci: they get the bacteria to kill their own “brother” cells.

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