Bacterial relocation II

November 26, 2012
Continuing on the subject of bacteriotherapy, there was a fascinating paper out last month in PLoS Pathogens by Lawley et al. As I said in the last post, C. difficile infection of the gut is bad news, and one of the best cures is fecal transplantation.  Lawley et al. describe experiments in a mouse model that closely approximates the situation in humans.  They showed that the epidemic strain of C. difficile 027/BI is much more of a terror than other strains, as the bug was highly contagious and liked to overstay its welcome longer than the other strains tested.

Variability in pathogenicity between strains of C. difficile is not surprising, as this has also been shown in humans.  But the authors made use of their mouse models to take the work further.  By culturing the feces from healthy mice, and using different mixes of the cultured microbes as treatment, they were able to discover a bacterial mixture that worked as well as a fecal transplantation in its ability to reduce C. difficile and restore the healthy microbial community diversity.  This result provides a potential treatment for those infected with these highly resistant and virulent strains, and also is one of the first potential live bacterial treatments likely to be developed from microbiome studies.

So, which bacteria were in the mix?  They identified the already-known species Staphylococcus warneri, Enterococcus hirae, Lactobacillus reuteri, and also three new species in the genera Anaerostipes, Bacteroidetes, and Enterorhabdus.  No doubt this team and others will be busy studying these species, as well as identifying their human counterparts. 


 

Bacterial relocation

November 4, 2012
Warning: Here comes the icky diarrhea blog.  Because I primarily write about microbiota, this was only a matter of time as the literature is replete with gut microbiota studies.  This abundance is due to lots of money being poured into figuring out the role of the gut microbiota; they are likely to influence a plethora of diseases through their role in immune system development, and fecal samples are easy to obtain!

Fecal samples are also relatively easy to transplant.  This may sound gross be...
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Hurricane highway

October 31, 2012
Monday we made sure all of the objects in our yard were secure, to prevent the winds of Sandy from giving them flight.  We didn't know what to expect and didn't want to see our patio table jump through our window.  Luckily the winds didn't do any damage and we're all okay (and dry).

This got me thinking about bacterial dispersal, and how high winds like those in a hurricane really stir things up. Ocean water columns are mixed, ocean waters come ashore, terrestrial soil becomes airborne, tree l...

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Phages as fighters

October 16, 2012

 
Not all ingested bacteria will be able to colonize the intestines upon arrival.  Some bacteria may not be adapted to living in the GI tract, and are merely passersby waiting to be ejected into the environment to find their favored niche.  Other bacteria are happy to be in the GI tract where nutrients are abundant, but must contend with the other hungry microbes and the vigilant immune system.  When competition is fierce, a particular bacterial species may “win” by producing toxins that k...

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Clothianidin debacle

October 11, 2012

Yesterday I attended a discussion forum for beekeepers in Ontario.  We (the beekeepers) were there to ask questions about bee deaths potentially caused by exposure to the pesticide Clothianidin.  Beekeepers in the US, Europe, and Canada (and probably other places too) have noticed massive bee die-offs that correspond closely to planting of corn.  Corn seeds are coated in pesticide prior to planting, and then shot into the soil using ...


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Microbial seeds

September 11, 2012

People with the genetic disease Cystic Fibrosis suffer from decreased lung and pancreatic functions, the former of which is often attributed to the thickened lung mucous that prevents expulsion of inhaled bacteria.  Many research groups are using DNA sequencing methods to characterize the communities of bacteria that live in CF lungs, and a smaller number of research groups have addressed the issue of intestinal bacterial communities that could be affected ...


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Pretty pollinators

August 29, 2012
When the lettuce bolts, the dill springs fluffy flowers, and the cilantro decides to become coriander, I sit by the plants staring and waiting.  I am sure the passersby think I've lost my mind.  But look at these lovely rewards!

A Braconid wasp (on coriander):


A European paper wasp, Polistes dominulus (on coriander):


Some type of sand wasp (?), on dill:


And our friend Apis mellifera, her collecting baskets loaded with pink pollen (on coriander):



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Hopeful monsters

August 21, 2012

For centuries scientists have been trying to figure out why some bacteria cause disease, while others are relatively harmless or even beneficial. The search has usually focused on identifying the genetic basis for the ability to cause disease, whether it be the mutation of an existing gene or the gain of a gene via horizontal transfer.  The latter process is (mostly) limited to bacteria, where gene sharing can enable niche exploration and adaptation.

Of special interest is ...


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Bt cotton ball

July 23, 2012

Utterance of “GM crops” usually has the effect of inciting anger in the public mind, while scientists shake their heads at public misunderstanding.  Although in principle I strongly favor the development of GM crops if they’re used to make agriculture more sustainable, the multinational companies that give us these technologies have really botched the relationship with farmer and public.  These companies can now only find camaraderie with scientists, business folk, and...


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Acalymma vittatum

July 11, 2012
The striped cucumber beetles have found a lovely new home: my squashes, melons, and cucumbers.  There must be thousands of them making whoopie on my several rows of curcurbits.  My strategy so far has been hand picking, followed by smashing or dropping in water with dish soap.  But I'm losing the battle.  I think a portable hand vacuum should level the playing field.....

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