Pseudomonas duriflava sp. nov., isolated from a desert soil

Abstract

A Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium, designated strain HR2 T , was isolated from a soil sample from the Taklimaken Desert in Xinjiang Province, China. Strain HR2T grew optimally at pH 7.0-8.0 and 30-37 6C in the presence of 0-1 % (w/v) NaCl. An analysis of 16S rRNA gene sequences revealed that strain HR2 T fell within the radiation of the genus Pseudomonas, the highest level of similarity being found with respect to Pseudomonas luteola IAM 13000 T (97.5 %); the levels of sequence similarity with respect to other recognized Pseudomonas species were ,96.4 %. DNA-DNA hybridization showed that the genetic relatedness between strain HR2 T and P. luteola IAM 13000 T was 53.2 %. The G+C content of the genomic DNA of strain HR2 T was 55.2 mol%. The major fatty acids were 18 : 1, summed feature 3 and 16 : 0. The hydroxylated fatty acids 10 : 0 3-OH, 12 : 0 3-OH and 12 : 0 2-OH were also present. The data obtained in this polyphasic study indicated that this isolate represents a novel species of the genus Pseudomonas, for which the name Pseudomonas duriflava sp. nov. is proposed. The type strain is HR2 T (5KCTC 22129 T 5CGMCC 1.6858 T ).The genus Pseudomonas sensu stricto originally comprised only species belonging to Pseudomonas RNA homology group I (Palleroni, 1984) in the Gammaproteobacteria (Kersters et al., 1996). However, the genus was subdivided into two main intrageneric clusters (as reviewed by Anzai et al., 2000): the first cluster comprised six groups and the second had only one group. Pseudomonads are abundant in various environments, such as water, air and soil. In our search for organisms capable of growing in desert ecosystems, a bacterial strain, designated HR2 T , was isolated and analysed using polyphasic taxonomy. An analysis of 16S rRNA gene sequence similarities indicated that the isolate was closely related to the Pseudomonas aeruginosa/Pseudomonas stutzeri group within the first cluster and formed a distinct line. On the basis of phenotypic and genotypic evidence, it is proposed that strain HR2T represents a novel species of the genus Pseudomonas. Strain HR2T was isolated from a desert soil sample by using the usual dilution plating technique on Luria-Bertani (LB) agar (l 21: 5 g yeast extract, 10 g tryptone, 10 g NaCl, pH 7.0) incubated for 2 days at 30 u C under aerobic conditions. The isolate was cultivated routinely on LB agar or in LB broth at the same temperature. The strain was maintained in a glycerol suspension (20 %, v/v) at 270 u C.Amplification and sequencing of the 16S rRNA gene were performed according to a method described by Cui et al. (2001), but which was modified slightly by us: the primers used for the PCR amplification were 59-AGAGTTTGATCCTGGCTCAG-39 (forward) and 59-AAGGAGGTGATCCAAGCCGCA-39 (reverse), corresponding to positions 8-27 and 1521-1540, respectively, in the 16S rRNA sequence of Escherichia coli (Brosius et al., 1978). The resultant sequence (1404 bp) of strain HR2 T was compared with sequences available from the GenBank database, us...

Pseudomonas caeni sp. nov., a denitrifying bacterium isolated from the sludge of an anaerobic ammonium-oxidizing bioreactor

“…The DNA G+C contents of the two strains (with five replications) were 50.6±0.5 mol%. This level of G+C was greatly below the range (58-69 mol%) previously described for members of the genus Pseudomonas (Palleroni, 2005), however, Pseudomonas duriflava HR2 T , a recently described species, has also been reported to have a low DNA G+C content (55.2 mol%) (Liu et al, 2008). The DNA G+C contents of P. aeruginosa KCTC 1750 T , P. chlororaphis DSM 50083 T , P. fluorescens KCTC 12453 T , P. mendocina DSM 50017 T , P. pseudoalcaligenes KACC 10304 T , P. stutzeri KCTC 1066 T and P. putida KCTC 1751 T were also determined by the fluorescence monitoring method in this study and the results were consistent with those given in the literature (Palleroni, 2005) (Table 1).…”

Cytotoxicity and inflammatory potential of two Pseudomonas mosselii strains isolated from clinical samples of hospitalized patients

“…The genus Pseudomonas includes more than 100 species, a number that is increasing in time [2]. Nearly each year, a new species is indeed discovered, like P. duriflava, P. batumici or P. litoralis for example, isolated from a desert soil [3], the Caucasus Black sea coast [4] or from Mediterranean seawater [5], respectively. Due to its heterogeneity, the genus Pseudomonas has undergone numerous taxonomic changes depending on the criteria employed for their definition and delineation: phenotypic, physiologic or metabolic characteristics, siderotyping, phylogeny based on 16S rRNA and/or “housekeeping” genes, analysis of 16S-23S rRNA intergenic spacers (ITS) or the use of functional and ecological genetic markers such as oprF , oprD or gacA [2,6-8].…”

Remoção de BTEX por fungos em reator aeróbio de escoamento contínuo

“…Após o tempo de contato de 12 horas, a fração aquosa foi separada da gasolina por decantação simples, adicionando-se, ainda, o antibiótico estreptomicina 0,03 mg.L -1 (LIU et al, 2008), visando minimizar a ação de bactérias. A água poluída foi, então, utilizada na alimentação do reator, sendo que, previamente, o pH do meio foi ajustado para 4,5 -valor esse propício para o desenvolvimento dos fungos e dentro da faixa ótima para a atividade enzimática máxima para a maioria das enzimas (BOM; FERRARA; CORVO, 2008).…”