Thermonema rossianum sp. nov., a new thermophilic and slightly halophilic species from saline hot springs in Naples, Italy.

Six slightly halophilic, thermophilic bacterial strains were isolated from saline hot springs along the Bay of Naples, Italy. These strains produce bright yellow colonies and have a filamentous morphology and an optimum growth temperature of about 60 degrees C. Lipid composition and 16S ribosomal DNA sequence analyses showed that these strains belong to the genus Thermonema, a member of the cytophaga-flavobacter-bacteroides phylum. Growth was observed in medium containing 1 to 3% NaCl. The DNA G + C content was 50.9 mol%. DNA-DNA hybridization studies showed that these strains represent a new species of the genus Thermonema. We propose that strain NR-27T (T = type strain) and the other strains represent a new species, Thermonema rossianum. Strain NR-27 (= DSM 10300) is the type strain of this species.