Abstract
Several strains isolated from Antarctic winter sea water, sea-ice algal assemblages and quartz stone subliths were found to belong to a novel 16S rDNA sequence cluster within the family Flavobacteriaceae (Cytophaga--Flavobacterium--Bacteroides division). The strains were Gram-negative, non-motile, psychrotolerant, strictly aerobic, chemoheterotrophic rod-shaped cells that contained orange or yellow carotenoid pigments and required yeast extract when grown in defined mineral-salts media. The requirement for sodium ions varied between strains. Results of DNA--DNA hybridization analysis were used to divide the strains into four distinct genospecies, which were differentiated by physiological and nutritional characteristics. The DNA G+C content of the strains was 33--39 mol%. The fatty acid profiles of representative strains were very similar, with major constituents including i15:1omega10c, a15:1omega10c, i15:0, a15:0, i16:1omega6c, i17:1omega5c and 3-OH i16:0. The novel genus Aequorivita gen. nov., which has widespread distribution in the Antarctic region, is proposed. The genus comprises four species: the type species Aequorivita antarctica sp. nov. (type strain SW49(T)=ACAM 640(T)=DSM 14231(T)), Aequorivita lipolytica sp. nov. (type strain Y10-2(T)=ACAM 641(T)=DSM 14236(T)), Aequorivita crocea sp. nov. (type strain Y12-2(T)=ACAM 642(T)=DSM 14239(T)) and Aequorivita sublithincola sp. nov. (type strain 9-3(T)=ACAM 643(T)=DSM 14238(T)).