ISOLATION AND CHARACTERIZATION OF A HELICALLY TWISTED BACTERIUM RESEMBLING SELIBERIA.

Abstract

A seliberia-like bacterium (SLO), isolated from reverse osmosis membranes was characterized by morphological, physiological and DNA studies. The helically twisted cells of this organism were often observed in star-shaped clusters. Depending on nutritional conditions, cells ranged from 0.5 to 21 um in length and possessed prosthecae. Small motile cells were produced by asymmetric fission or by a budding process. Ovoid "generative" cells were observed in mixed culture conditions or when the pure culture isolate was grown in the presence of humic acid. The SLO oxidatively utilized glucose, maltose, xylose, cellobiose, and several amino acids as sole carbon and energy sources. The organism is a strict aerobe and does not anaerobically respire. The moles percent guanine plus cytosine (mol% G + C) of the SLO DNA was 38% as compared with 63-67% for Seliberia stellata. Although the cellular morphology and physiology of the SLO closely resembles that of S. stellata, the SLO is considered to be a new species of Seliberia based on the presence of prosthecae and the mol% G + C.