Microbial Ecology

[This question was originally asked on www.reddit.com/r/askscience on Jan 17, 2013] Why do microorganisms only begin breaking down our tissues after death? What stops them from doing so whilst we are still alive? The main reason is that our body maintains a multitude of barriers that largely prevent bacteria and other microorganisms from gaining entry. The first and most obvious of these barriers is the skin, but there are also similar barriers along all of your mucosal surfaces (gut, ear, genital tract etc). These barriers consist of cells that are knit together incredibly tightly (google:…
In the wake of the NASA excitement over the new arsenic study, and my promise to give a detailed review of the paper itself, I have recruited a colleague with strong opinons about the work, a solid chemistry and microbiology background, and "Dr." in front of his name to share his analysis. I will be posting have posted my personal and less-technical take on the whole thing soon, so stay tuned as well. Dr. Alex Bradley uses modern geochemistry and microbiology tools to study the evolution of life and Earth. He has the following to say about the paper. There's been a lot of hype around the…
Arsenic it is... but the point really isn't arsenic. That is what Dr. Felisa Wolfe-Simon stressed at the end of the NASA press conference today - that the research being unveiled is just opening the door to other unexamined possibilities for life. She said "I am interested in exceptions, why aren't things constants in nature?" Her team's new finding is that certain microbes are capable of creating DNA with arsenic rather than phosphorus as the molecular backbone. These are microbes closely related to well known microbes, but their ability to make this substitution is remarkable, and…
Rarely do I read papers whose title really sums up exactly what is so cool about the study in a succinct way, free of jargon. I think that "First Investigation of the Microbiology of the Deepest Layer of Ocean Crust" does just that. It isn't trying to be sexy... it just is! Examining the microbial communities in the so-called "deep subsurface biosphere" is a relatively new field. Until recently people didn't think there was much, or really any, life deep in Earth's crust. As with many scientific assumptions made before scientists had the opportunity to actually study a new environment...…