7 posts tagged with microbiology and bacteria. (View popular tags)
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As Paracelsus put it, "the dose makes the poison."

Dr Bruce Ames, a toxicologist and one of the world's most cited scientists, discusses the impact of his Ames test, "toxic chemicals," and scaremongering [more inside]
posted by Blasdelb on Nov 6, 2013 - 22 comments

 

The answer, my friend, is blowing in the wind: E. Coli & Cloud Formation

Scientists Find Bacteria Survive at High Altitudes
Study finds significant microorganism populations in middle and upper troposphere
Microbiome of the upper troposphere: Species composition and prevalence, effects of tropical storms, and atmospheric implications
See also Properties of biological aerosols and their impact on atmospheric processes

posted by y2karl on Jan 29, 2013 - 17 comments

The players in a mutualistic symbiosis: insects, bacteria, viruses, and virulence genes.

One of the many problems farmers of various kinds of legumes need to deal with is the pea aphid. They reproduce incredibly fast and live by sucking the sap out of the plants, an electron micrograph of one in action. However, while they are terrifying parasites of legumes, they have their own yet more horrific parasites, a parasitoid wasp. Here is a really nice close up picture of one doing its thing, a video of the act, and here is a brain meltingly horrific video of a dissection of the mummified aftermath 8 days later. Essentially, these wasps deposit their eggs in a pea aphid and the growing larva feeds on it, developing there for about a week, and then consuming the host from the inside out like a Xenomorph. When it’s done, the wasp larva dries the aphid’s cuticle into a papery brittle shell and an adult wasp emerges from the aphid mummy. Legume farmers love them, and you can even order their mummies online these days. However, farmers noticed that the wasps didn't work as effectively on all of the aphids, and so researchers went to work figuring out why. It turns out that all aphids have a primary bacterial endosymbiont living inside their cells, in addition to and just like a mitochondria, and that many have some combination of five other secondary endosymbionts. Interestingly, two of those other five, Hamiltonella defensa and Serratia symbiotica have been shown to confer varying levels of resistance to the parasitoid wasp, allowing the aphid to survive infection. However, it turns out that there is yet one more layer to this story, [more inside]
posted by Blasdelb on Oct 22, 2012 - 50 comments

Constitutive formation of caveolae in a bacterium.

Constitutive formation of caveolae in a bacterium. [Full Text]
Caveolin plays an essential role in the formation of characteristic surface pits, caveolae, which cover the surface of many animal cells. The fundamental principles of caveola formation are only slowly emerging. Here we show that caveolin expression in a prokaryotic host lacking any intracellular membrane system drives the formation of cytoplasmic vesicles containing polymeric caveolin. Vesicle formation is induced by expression of wild-type caveolins, but not caveolin mutants defective in caveola formation in mammalian systems. In addition, cryoelectron tomography shows that the induced membrane domains are equivalent in size and caveolin density to native caveolae and reveals a possible polyhedral arrangement of caveolin oligomers. The caveolin-induced vesicles or heterologous caveolae (h-caveolae) form by budding in from the cytoplasmic membrane, generating a membrane domain with distinct lipid composition. Periplasmic solutes are encapsulated in the budding h-caveola, and purified h-caveolae can be tailored to be targeted to specific cells of interest.
Elio Schaechter writes in plain English about how fantastically amazing and unexpected the researchers actually pulling this off is, and he also talks about it in more detail in his podcast.
posted by Blasdelb on Oct 18, 2012 - 22 comments

I really dig infectious diseases (much to the dismay of those dining with me).

How did hookworm infections slow the economy of the postbellum South? Do body mites play a role in diseases such as rosacea? Did fermenting seal flippers in Tupperware instead of traditional containers increase Native Alaskan botulism rates? Body Horrors is the blog of microbiologist Rebecca Kreston, who aims to explore the intersection of infectious diseases, the human body, public health and anthropology.
posted by emjaybee on Sep 24, 2011 - 36 comments

The Science of Eggnog

Want to make eggnog weeks ahead of time? You might try this recipe, courtesy of The Rockefeller University's Dr. Rebecca Lancefield (PDF biographic article). In this 2008 video, her colleagues demonstrate how to make it; they suggest starting it now, tasting it at Thanksgiving, and drinking it at Christmas. In their 2009 follow-up video, they intentionally add Salmonella to the recipe as they make it, to see if the added liquor kills off the infection. Videos courtesy of Science Friday. (BONUS LINK: if you missed last year's Puerto Rican Nog celebration, get ready for the 9th annual NYC Coquito Contest!)
posted by Greg Nog on Nov 10, 2010 - 24 comments

Bacteria 'R' Us

Bacteria can communicate with each other, take concerted action, influence human physiology, alter human thinking, and work together to change their environment. The bacteria in your gut are talking to each other, and to you, and you are talking back to them. The mind boggles. [more inside]
posted by exphysicist345 on Oct 19, 2010 - 55 comments

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