RHODOSPIRA-TRUEPERI GEN-NOV, SPEC NOV, A NEW PHOTOTROPHIC PROTEOBACTERIUM OF THE ALPHA-GROUP

A new phototrophic purple bacterium was isolated from a flat, laminate d microbial mat in a salt marsh near Woods Hole, Mass., USA. The spira l-shaped bacterium was highly motile and had bipolar tufts of flagella and intracytoplasmic membranes of the vesicular type. The major photo synthetic pigments were identified as the carotenoid tetrahydrospirill oxanthin and bacteriochlorophyll b. The long wavelength in vivo absorp tion maximum of the bacteriochlorophyll was at 986 nm. The marine bact erium showed optimal growth in the presence of 2% NaCl. It utilized a number of organic substrates as carbon and energy sources and required vitamins and sulfide as a reduced sulfur source for growth. In the pr esence of sulfide, elemental sulfur globules were formed outside the c ells. Elemental sulfur was not further oxidized to sulfate. The new is olate had a unique lipid and fatty acid composition, and according to the 16S rRNA gene sequence, it is most similar to Rhodospirillum rubru m. It is described as a new species and assigned to a new genus with t he proposed name Rhodospira trueperi.