title: Diversity of bacteriorhodopsins in different hypersaline waters from a single Spanish saltern.
abstract: Haloarchaeal rhodopsins are a diverse group of transmembrane proteins that use light energy to drive several different cellular processes. Two rhodopsins, bacteriorhodopsin and halorhodopsins, are H+ and Cl- ion pumps, respectively, and two rhodopsins, sensory rhodopsin I and II, regulate phototaxis. Bacteriorhodopsin is of special interest as it is a non-chlorophyll-based type of phototrophy (i.e. generation of chemical energy from light energy). However, very little is known about the diversity and distribution of rhodopsin genes in hypersaline environments. Here, we have used environmental PCR and cloning techniques to directly retrieve rhodopsin genes from three different salinity ponds located in a sea salt manufacturing facility near Alicante, Spain. Our survey resulted in the discovery of previously concealed variation including what is hypothesized to be bacteriorhodopsin genes from the uncultivated square morphotype that dominates these environments. In some instances, identical genes were discovered in seemingly different habitats suggesting that some haloarchaea are present over widely varying concentrations of salt.
authors.affiliation: Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Building, Halifax, NS B3H 4H7, Canada. rpapke@dal.ca
authors.forename: R Thane
authors.initials: RT
authors.lastname: Papke
authors.forename: Christophe J
authors.initials: CJ
authors.lastname: Douady
authors.forename: W Ford
authors.initials: WF
authors.lastname: Doolittle
authors.forename: Francísco
authors.initials: F
authors.lastname: Rodríguez-Valera
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000235:genetics; D001436:Bacteriorhodopsins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D019641:DNA, Archaeal / Q000737:chemistry / Q000302:isolation & purification; D014644:Genetic Variation / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012623:Seawater / Q000032:analysis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013030:Spain; D014871:Water Microbiology
chemical_list: D019641:DNA, Archaeal; D008565:Membrane Proteins; D001436:Bacteriorhodopsins