Some bacteria degrade explosives, others prefer boiling methanol
The recent list of completely sequenced microbial genomes is relatively short. Still, it includes some remarkable environmental microorganisms, such as the sulfur-reducing crenarchaeon Ignicoccus hospitalis, host of the smallest archaeon Nanoarchaeum equitans, a marine bacterium that degrades nitramine explosives and two enterobacteria that are commonly found in soil and water habitats but can also infect humans, particularly newborns, causing sepsis and neonatal meningitis.
The largest of the recently sequenced genomes comes from the early-diverging amitochondrial eukaryote Giardia lamblia. In accordance with earlier reports, G. lamblia encodes a simplified archaeal-like DNA replication machinery, a yeast-like machinery for transcription synthesis and RNA processing and a limited set of largely bacterial-like metabolic enzymes.
The past few months have brought five new genomes of Rickettsia spp., doubling the total number of complete rickettsial genomes. This genus, named after Howard Taylor Ricketts (1871-1910), who described the first bacterium of this group exactly 100 years ago, consists of arthropod-borne alpha-Proteobacteria, some of which are important pathogens. Human diseases caused by rickettsiae include epidemic typhus (caused primarily by Rickettsia prowazekii and Rickettsia typhi), scrub typhus (Rickettsia tsutsugamushi), the Rocky Mountain spotted fever (Rickettsia rickettsii), Mediterranean spotted fever (Rickettsia conorii), and rickettsialpox (Rickettsia akari). Rickettsiae are obligately intracellular pathogens that are transmitted to their vertebrate hosts by ticks, mites or lice.
Vibrio harveyi is a widespread marine bacterium, often found associated with marine animals, such as octopi and shrimp. For a number of years, it has been a favorite model organism to study regulation of bioluminescence by quorum sensing. It has a very complex regulatory system that should now become much easier to comprehend.
Thermotoga lettingae strain TMO was isolated in 2002 from a sulfate-reducing bioreactor operated at 65°C with methanol as the sole carbon and energy source. The unique ability of T. lettingae to utilize methanol near its boiling point of 64.7°C makes it a very attractive object for biotechnology.
Tags: Bacteria, Biology, Environment, Genetics, Microbiology, Science
