Leucobacter

Abstract: A Gram-positive, rod-shaped, aerobic, non-motile, yellow-pigmented bacterial strain, designated MM2LB(T), was isolated from a chironomid egg mass that was sampled in a waste stabilization pond in northern Israel. 16S rRNA gene sequence analysis indicated that the isolate should be placed in the genus Leucobacter (family Microbacteriaceae). Levels of 16S rRNA gene sequence similarity between strain MM2LB(T) and the type strains of recognized Leucobacter species were 97.1 % or lower. The dominant cellular fatty acids of strain MM2LB(T) were anteiso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0), which are typical of members of the genus Leucobacter. Strain MM2LB(T) grew at 17-37 degrees C, in the presence of 0-7.0 % NaCl and at pH 4.0-9.5. Cell-wall amino acids were alanine, glycine, threonine, 2,4-diaminobutyric acid, glutamic acid and gamma-aminobutyric acid in a B-type cross-linked peptidoglycan. The quinone system consisted of menaquinones MK-11, MK-10 and MK-12. The novel isolate was able to grow in medium containing 18 mM Cr(VI). On the basis of phenotypic properties and phylogenetic distinctiveness, strain MM2LB(T) is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacter chironomi sp. nov. is proposed. The type strain is MM2LB(T) (=LMG 24399(T)=DSM 19883(T)).

Abstract: A Gram-positive, irregular rod-shaped, non-motile, yellow-pigmented bacterium, strain JG 31T, was isolated in the course of identifying chromium-resistant soil bacteria. 16S rRNA gene sequence analysis of the isolated bacterium indicated its phylogenetic position within the genus Leucobacter. Binary 16S rRNA gene sequence alignments of the isolated bacterium with the 11 species of the genus recognized at the time of writing revealed sequence similarities of more than 97 % with Leucobacter alluvii (GenBank accession no: AM072820; 99.4 %), Leucobacter iarius (AM040493; 98.2 %), Leucobacter aridicollis (AJ781047; 97.8 %), Leucobacter komagatae (AB007419; 97.4 %), Leucobacter chironomi (EU346911; 97.1 %) and Leucobacter luti (AM072819; 97.1 %). In contrast, DNA–DNA hybridization experiments showed similarity values below 28 % for DNA samples from the most closely related type strains of L. alluvii, L. aridicollis and L. iarius. Protein analysis by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and automated RiboPrinting using the restriction enzyme PvuII differentiated strain JG 31T from all type strains of the genus Leucobacter. The dominant fatty acids of the novel isolate were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0, while the quinone system consisted of menaquinones MK-11, MK-10, MK-9 and MK-8. In a B-type cross-linked peptidoglycan, the cell-wall amino acids were alanine, glycine, threonine, glutamic acid and 2,4-diaminobutyric acid. Strain JG 31T was able to grow in a medium containing up to 300 mM K2CrO4 and showed cellular aggregation in response to chromate stress. From biochemical and genomic analyses, the new strain is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacter chromiiresistens sp. nov. is proposed. The type strain is strain JG 31T ( = DSM 22788T = CCOS 200T).