Halomonas coralii sp. nov. Isolated from Mussismilia braziliensis.

We report here the novel species Halomonas coralii. The nearly complete genome of strain 362.1T consisted of 4.4 Mbp (3989 CDS; 66.3% GC). Genomic taxonomy analysis demonstrates that the novel strain has < 83% AAI and < 29% GGDH towards its closest neighbors.

Biosynthesis and characterization of polyhydroxyalkanoates produced by an extreme halophilic bacterium, Halomonas nitroreducens, isolated from hypersaline ponds.

AIMS: Morphological, biochemical and genotypic characterization of a halophilic bacterium isolated from hypersaline ponds located at Las Coloradas (Río Lagartos, Yucatán, Mexico). Characterization of polymer produced by this strain was also performed. METHODS AND RESULTS: Twenty strains were isolated from water samples of salt ponds and selected based on both morphological features and their PHA storage capacity, which were determined by SEM and staining methods with Nile red and Nile blue, respectively; strains were also analysed by the fluorescence imaging technique. Among them, JCCOL25.8 strain showed the highest production of PHA's reason why phenotypic and genotypic characterization was performed; this strain was identified as Halomonas nitroreducens. Polymer produced by this strain was characterized by FTIR, DSC, GPC and EDX spectroscopy. Results indicated that the biosynthesized polymer was polyhydroxybutyrate (PHB) which had a melting peak at 170°C and a crystallinity percentage of about 36%. CONCLUSIONS: Based on phenotypic and genotypic aspects, JCCOL25.8 strain was identified as H. nitroreducens and it was capable to accumulate PHB. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, there is only one study published on the biosynthesis of PHA's by H. nitroreducens strains, although the characterization of the obtained polymer was not reported.

Chemotactic responses to gas oil of Halomonas spp. strains isolated from saline environments in Argentina.

In this study, two halophilic bacterial strains isolated from saline habitats in Argentina grew in the presence of gas oil. They were identified as Halomonas spp. and Nesterenkonia sp. by 16S ribosomal RNA sequencing. Chemotaxis towards gas oil was observed in Halomonas spp. by using swimming assays.

Chemotactic responses to gas oil of Halomonas spp. strains isolated from saline environments in Argentina / Respuesta quimiotáctica hacia gas oil de cepas de Halomonas spp. aisladas de ambientes salinos de Argentina

In this study, two halophilic bacterial strains isolated from saline habitats in Argentina grew in the presence of gas oil. They were identified as Halomonas spp. and Nesterenkonia sp. by 16S ribosomal RNA sequencing. Chemotaxis towards gas oil was observed in Halomonas spp. by using swimming assays.

En el presente trabajo se aislaron dos cepas bacterianas halofílicas a partir de muestras obtenidas en ambientes salinos de Argentina, que crecieron en presencia de gasoil como única fuente de carbono. Las cepas aisladas se identificaron como Halomonas spp. y Nesterenkonia sp. mediante secuenciación del gen del ARN ribosomal 16S. En ensayos de swimming, las cepas del genero Halomonas spp. mostraron una respuesta quimiotáctica hacia el gas oil.

Halomonas vilamensis sp. nov., isolated from high-altitude Andean lakes.

A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming bacterium (SV325(T)) was isolated from the sediment of a hypersaline lake located 4600 m above sea level (Laguna Vilama, Argentina). Strain SV325(T) formed cream to pink colonies, was motile and moderately halophilic, and tolerated NaCl concentrations of 1-25 % (w/v) with an optimum of 5-10 % (w/v). Growth occurred at 5-40 °C (optimum around 30 °C) and at pH 5.0-10.0 (optimum 7.0-8.0). The bacterium did not produce exopolysaccharides and stained positively for intracellular polyphosphate granules but not for poly-ß-hydroxyalkanoates. It produced catalase and oxidase, reduced nitrate to nitrite, hydrolysed gelatin, did not produce acids from sugars and utilized a limited range of substrates as carbon and energy sources: acetate, caproate, fumarate, dl-ß-hydroxybutyrate, malate, maleate, malonate and succinate. The predominant ubiquinones were Q-9 (92.5 %) and Q-8 (7.5 %), the major fatty acids were C(19 : 0) cyclo ω8c, C(16 : 0), C(17 : 0) cyclo and C(16 : 1)ω7c/iso-C(15:0) 2-OH, and the DNA G+C content was 55.0 mol%. Phylogenetic analyses based on the 16S rRNA gene indicated that strain SV325(T) belongs to the genus Halomonas in the class Gammaproteobacteria. Physiological and biochemical tests allowed phenotypic differentiation of strain SV325(T) from closely related species with validly published names. We therefore propose a novel species, Halomonas vilamensis sp. nov., with type strain SV325(T) ( = DSM 21020(T)  = LMG 24332(T)).

Halomonas andesensis sp. nov., a moderate halophile isolated from the saline lake Laguna Colorada in Bolivia.

A moderately halophilic, motile, Gram-negative, rod-shaped bacterium, strain LC6(T), was isolated from a water sample of lake Laguna Colorada in the Bolivian Andes. The major cellular fatty acids were C(18 : 1)omega7c, iso-C(16 : 1)omega7c 2-OH, C(16 : 0) and C(12 : 0) 3-OH. The respiratory ubiquinones found in strain LC6(T) were Q-9 (97 %) and Q-8 (3 %). Strain LC6(T) was aerobic, heterotrophic, and able to utilize various carbohydrates and other substrates as carbon source. The G+C content of the genomic DNA of strain LC6(T) was 52.5 mol%. The organism was able to grow at pH 6.0-11.0 (optimum, pH 7.0-8.0), at 4-45 degrees C (optimum, 30-35 degrees C) and in the presence of 0.5-20 % (w/v) NaCl (optimum, 1-3 %, w/v). Based on 16S rRNA gene sequence analysis, strain LC6(T) was most closely related to Halomonas hydrothermalis DSM 15725(T) and Halomonas venusta DSM 4743(T) (98.8 % similarity), followed by Halomonas aquamarina DSM 30161(T), Halomonas axialensis DSM 15723(T) and Halomonas meridiana DSM 5425(T) (98.4 %). However, levels of DNA-DNA relatedness between strain LC6(T) and the above type strains were low (<31 %). Strain LC6(T) resembled recognized Halomonas species with respect to various physiological, biochemical and nutritional characteristics. Combined phenotypic data and DNA-DNA hybridization data supported the conclusion that strain LC6(T) represents a novel species of the genus Halomonas, for which the name Halomonas andesensis is proposed. The type strain is LC6(T) (=CCUG 54844(T)=LMG 24243(T)=DSM 19434(T)).

Halomonas avicenniae sp. nov., isolated from the salty leaves of the black mangrove Avicennia germinans in Puerto Rico.

A Gram-negative, short rod to oval-shaped bacterium (strain MW2a(T)) was isolated from the surface of leaves of the black mangrove Avicennia germinans and subjected to a polyphasic taxonomic study. Strain MW2a(T) was moderately halophilic, growing at NaCl concentrations in the range 0-25 % (w/v) with optimum growth at 5 % (w/v) NaCl. Growth occurred at 12-40 degrees C (optimum, 30-35 degrees C) and at pH 5.0-9.0 (optimum, pH 7.0-8.0). Strain MW2a(T) was strictly aerobic. Phylogenetic analysis based on the 16S rRNA gene showed that the strain belongs to the genus Halomonas. The closest relative was Halomonas marisflavi, with 98.6 % 16S rRNA gene sequence similarity. The DNA G+C content of strain MW2a(T) was 61.5 mol%, which is in the range of values for Halomonas species. DNA-DNA hybridization with H. marisflavi showed a relatedness of 42 % and lower values were obtained with respect to other related Halomonas species. The major fatty acids were C(16 : 0), C(19 : 0) cyclo omega8c, C(18 : 1)omega7c and C(12 : 0) 3-OH. Overall, the phenotypic, genotypic and phylogenetic results presented in this study demonstrate that strain MW2a(T) represents a novel species within the genus Halomonas. The name Halomonas avicenniae sp. nov. is proposed, with strain MW2a(T) (=CECT 7193(T)=CCM 7396(T)) as the type strain.

Halomonas boliviensis sp. nov., an alkalitolerant, moderate halophile isolated from soil around a Bolivian hypersaline lake.

Halomonas boliviensis sp. nov. is proposed for two moderately halophilic, psychrophilic, alkalitolerant bacteria, LC1(T) (=DSM 15516(T)=ATCC BAA-759(T)) and LC2 (=DSM 15517=ATCC BAA-760), both of which were isolated from a soil sample around the lake Laguna Colorada, located at 4300 m above sea level in the south-west region of Bolivia. The bacteria are aerobic, motile, Gram-negative rods that produce colonies with a cream pigment. Moreover, they are heterotrophs that are able to utilize various carbohydrates as carbon sources. The organisms reduce nitrate and show tryptophan deaminase activity. The genomic DNA G+C contents were 51.4 mol% for isolate LC1(T) and 52.6 mol% for isolate LC2. Based on 16S rDNA sequence analysis, isolates LC1(T) and LC2 were identified as members of the genus Halomonas and clustered closely with Halomonas variabilis DSM 3051(T) and Halomonas meridiana DSM 5425(T). However, DNA-DNA relatedness between the new isolates and the closest related Halomonas species was low.

Phylogenetic analysis of bacterial populations in waters of the former Texcoco Lake, Mexico.

Molecular techniques were used to compare the compositions of the bacterial communities of the 2 following lagoons from the former soda Texcoco Lake, Mexico: the restored Facultativa lagoon and the Nabor Carrillo lagoon. Ribosomal intergenic spacer analysis (RISA) revealed that bacterial communities of the 2 lagoons were different and presented a relatively low diversity. Clone libraries of 16S rDNA genes were constructed, and significant phylotypes were distinguished by restriction fragment length polymorphism (RFLP). A representative clone from each phylotype was partially sequenced. Molecular identification and phylogenetic analyses based on ribosomal sequences revealed that the Facultativa lagoon harbored mainly gamma- and beta-Proteobacteria, low G+C Gram-positive bacteria, and several members of the Halobacteriaceae family of archaea. The Nabor Carrillo lagoon mainly included typical halophilic and alkaliphilic low G+C Gram-positive bacteria, gamma-Proteobacteria, and beta-Proteobacteria similar to those found in other soda lakes. Several probably noncultured new bacterial species were detected. Three strains were isolated from the Nabor Carrillo lagoon, their partial 16S rDNA sequences were obtained. On this basis, they were identified as Halomonas magadiensis (H1), Halomonas eurihalina (H2), and Staphylococcus sciuri (H3). This is the first study that uses molecular techniques to investigate potential genetic diversity in the Texcoco lakes. In this preliminary evaluation, we infer the presence of alkalophilic, halophilic, or haloalkaliphilic bacteria potentially useful for biotechnology.