Numerical Taxonomy of Moderately Halophilic Gram-negative Bacteria from Hypersaline Soils

Abstract

A total of 132 moderately halophilic bacteria were isolated from hypersaline soils with a C1-content between 2-36 and 12.72% (w/v) located near Alicante (S.E. Spain) and examined for 98 phenotypic characteristics including their response to cytological, physiological, biochemical and nutritional tests. They were submitted to a numerical analysis together with six reference strains using both simple matching (SsM) and Jaccard (S,) coefficients, and cluster analysis was carried out by the unweighted pair group method of association (UPGMA), single linkage and complete linkage. With the S, coefficient and UPGMA clustering, eight phenons were obtained at the 65% similarity level. From each phenon representative strains were chosen for the determination of DNA base composition and for electron microscopy. Bacteria belonging to phenons D, E, and F were assigned to the genus Alcaligenes. Phenon G included 27 strains assigned to Acinetobacter, but the high G + C composition (58.9 mol%) of a representative strain of this phenon suggests that it may represent a new taxon. Phenons A, B, and C were designated Flavobacterium and phenon H was Pseudomonas. The bacteria found in these environments are not related to those from hypersaline waters or normal soils.

A Detailed Phenotypic Characterisation of the Type Strains of Halomonas Species

“…For example, to test acid production from sugars, we used two different culture media: Leifson medium, with a low peptone and high carbohydrate content (LEIFSON, 1963), and MH basal medium (QUESADA et al, 1983), which had more peptones and a lower carbohydrate content. In this way our results indicated that H. elongata was not able to ferment glucose, just as other authors such as VENTOSA et al (1998) have also observed.…”

“…MH medium (QUESADA et al, 1983) with 7.5% (w/v) sea-salt solution (RODRÍGUEZ-VALERA et al, 1981) was used to maintain the strains, to prepare the inocula and as the basal medium for phenotypic tests, unless otherwise stated. The pH was adjusted to 7.2 with 1M NaOH except for the media used for growing H. magadiensis and H. campisalis, which were adjusted to pH 9.…”

Isolation, classification, phylogenetic analysis and scanning electron microscopy of halophilic, halotolerant and alkaliphilic actinomycetes isolated from hypersaline soil

“…All these moderate halophilic species belong to the low G+C group of the gram-positive phylum, only Nesterenkonia (formerly Micrococcus halobius) is within the high G+C group (Mota et al, 1997;Stackebrandt et al, 1995). Saline soils appear to yield mostly halotolerant rather than halophilic microorganisms, presumably reflecting adaptation to periodic edisodes of relatively high dilution (Quesada et al, 1982(Quesada et al, , 1983. Saline soils have been somewhat neglected as compared to hypersaline aquatic environments.…”

Virgibacillus sediminis sp. nov., a moderately halophilic bacterium isolated from a salt lake in China

“…Growth under anaerobic conditions was determined on MA and in MB supplemented with 5 % (w/v) NaCl and with or without 0.5 % (w/v) glucose or 0.1 % (w/v) nitrate, by using the GasPak Anaerobic System (BBL) according to the manufacturer's instructions. Oxidation/fermentation of glucose and respiration on fumarate, nitrate and nitrite were studied according to the procedures described by Mata et al (2002) by using MH medium (Quesada et al, 1983) with 7.5 % sea salts solution (Rodriguez-Valera et al, 1981) as the basal medium. Nutritional tests were performed by using classical methods (Ventosa et al, 1982) in modified Koser medium (Koser, 1923) [containing (l 21 ): 50 g NaCl, 2 g KCl, 0.2 g MgSO 4 .…”