By analyzing genomic sequences from more than 400 strains of the bacterium that causes anthrax, researchers have provided the first evidence that the severity — technically known as virulence — of specific strains may be related to the number of copies of certain plasmids they carry. Plasmids are genetic structures of the cell that can reproduce independently, and are responsible for producing the anthrax toxin and other virulence factors.
In ocean expanses where oxygen has vanished, newly discovered bacteria are diminishing additional life molecules. They help make virtual dead zones even deader. Now, a team led by the Georgia Institute of Technology has discovered members of a highly prolific bacteria group known as SAR11 living in the world’s largest oxygen minimum zone. The team has produced unambiguous evidence that the bacteria play a major role in denitrification.
The human microbiome, a diverse collection of microorganisms living inside us and on our skin, has attracted considerable attention for its role in a broad range of human health issues. Now, researchers are discovering that the built environment also has a microbiome, which includes a community of potentially-pathogenic bacteria living inside water supply pipes. A paper published March 11 in the journal Applied and Environmental Microbiology describes microbial communities found in shower hoses at a major U.S. hospital. The study documented bacteria – and related genes – using cutting-edge metagenomic techniques that allow the characterization of organisms that cannot be detected using traditional culture-based microbiology assays.