Rhodovulum algae sp. nov., isolated from an algal mat.

A reddish-brown-pigmented, phototrophic bacterium, designated strain JA877T, was isolated from a brown algae mat sample collected from Jalandhar beach, Gujarat, India. On the basis of the 16S rRNA gene sequence, strain JA877T belongs to the class Alphaproteobacteria and is closely related to the type strains Rhodovulum viride JA756T (99.0 %), Rhodovulum sulfidophilum Hansen W4T (98.9 %), Rhodovulumvisakhapatnamense JA181T (98.8 %),Rhodovulum kholense JA297T (97.5 %) and Rhodovulum salis JA746T (97.0). However, strain JA877T showed only 20-45 % relatedness with its phylogenetic neighbours and had a ∆Tm between 5.8 and 7.0 °C. The major respiratory quinone was ubiquinone-10 (Q10), and the polar lipid profile was composed of the major components phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, two unidentified sulfolipids and five unidentified lipids. The major fatty acids were C18 : 1ω5c, C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C18 : 0. The DNA G+C content was 64.5 mol%. On the basis of 16S rRNA gene sequence analysis, physiological data, and chemotaxonomic and molecular differences, strain JA877T is significantly different from other species of the genus Rhodovulum and represents a novel species, for which the name Rhodovulum algae sp. nov. is proposed. The type strain is JA877T (=LMG 29228T= KCTC 42963T).

Rhodovulum aestuarii sp. nov., isolated from a brackish water body.

A yellowish brown, phototrophic, purple non-sulfur bacterium, strain JA924T, was isolated in pure culture from a brackish water sample collected from an estuary. Single cells were oval to rod-shaped, non-motile and Gram-stain-negative and had a vesicular architecture of intracellular photosynthetic membranes. Bacteriochlorophyll-a and carotenoids of the spheroidene series were present as photosynthetic pigments. Photolithoautotrophy, chemo-organoheterotrophy and photo-organoheterotrophy were the growth modes observed. Strain JA924T had complex growth requirements. Strain JA924T was mesophilic and moderately halophilic. The DNA G+C content was 64 mol% (HPLC). The major cellular fatty acids were C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C18 : 0. The major quinone was ubiquinone-10 (Q-10). Phosphatidylglycerol, phosphatidylethanolamine, sulfolipid and an aminolipid were the main polar lipids of strain JA924T. EzTaxon-e blast searches based on the 16S rRNA gene sequence of JA924T revealed highest similarity with Rhodovulum mangrovi AK41T (98.19 %) and other members of the genus Rhodovulum ( < 95.71 %). Strain JA924T was further identified to be distantly related to Rhodovulum mangrovi AK41T ( < 29 % based on DNA-DNA hybridization and ΔTm (>5 °C). Phenotypic, chemotaxonomic and molecular differences indicate that strain JA924T represents a novel species of the genus Rhodovulum, for which the name Rhodovulum aestuarii sp. nov. is proposed. The type strain is JA924T ( = LMG 29031T = KCTC 15485T).

Rhodovulum mangrovi sp. nov., a phototrophic alphaproteobacterium isolated from a mangrove forest sediment sample.

A novel Gram-staining-negative, purple non-sulfur bacterium, strain AK41(T), was isolated from a sediment sample collected from Coringa mangrove forest, Andhra Pradesh, India. A red-brownish-coloured culture was obtained on modified Pfennig medium after enrichment with 2 % NaCl and 0.3 % pyruvate under 2000 lx illumination. Individual cells were ovoid-rod-shaped and non-motile. Bacteriochlorophyll a and carotenoids of the spheroidene series were present as photosynthetic pigments. Strain AK41(T) was halophilic and grew photoheterotrophically with a number of organic compounds as carbon sources and electron donors. It was unable to grow photoautotrophically. It did not utilize sulfide or thiosulfate as electron donors. The fatty acids were found to be dominated by C16 : 0 and C18 : 1ω7c. Strain AK41(T) contained phosphatidylglycerol, phosphatidylethanolamine, an unknown aminolipid and four unknown lipids as polar lipids. Q-10 was the predominant respiratory quinone. The DNA G+C content of strain AK41(T) was 68.9 mol%. 16S rRNA gene sequence analysis indicated that strain AK41(T) was a member of the genus Rhodovulum and was closely related to Rhodovulum sulfidophilum, with 96.0 % similarity to the type strain; the 16S rRNA gene sequence similarity to the type strains of other species of the genus Rhodovulum was 93.9-95.8 %. Phylogenetic analyses indicated that strain AK41(T) clustered with the type strains of Rhodovulum marinum, Rdv. kholense, Rdv. sulfidophilum and Rdv. visakhapatnamense with sequence similarity of 95.9-96.2 %. Based on data from the current study, strain AK41(T) is proposed to represent a novel species of the genus Rhodovulum, for which the name Rhodovulum mangrovi sp. nov. is proposed. The type strain of Rhodovulum mangrovi is AK41(T) ( = MTCC 11825(T) = JCM 19220(T)).

Rhodovulum salis sp. nov. and Rhodovulum viride sp. nov., phototrophic Alphaproteobacteria isolated from marine habitats.

Two strains (JA746(T) and JA756(T)) having yellowish brown-to-green pigment were isolated from a solar saltern and a pink pond, respectively. While both strains were non-motile and shared the presence of bacteriochlorophyll-a, major cellular fatty acids (C18 : 1ω7c, C16 : 0, C18 : 0), quinone (Q-10), polar lipids and hopanoids, they differed from each other in their carotenoid composition. The G+C content of genomic DNA of strains JA746(T) and 756(T) was 62.4 and 63.3 mol%, respectively. The 16S rRNA gene-based EzTaxon-e blast search analysis of strains JA746(T) and 756(T) indicated highest sequence similarity with members of the genus Rhodovulum in the family Rhodobacteraceae of the class Alphaproteobacteria. Strain JA746(T) has high sequence similarities with Rhodovulum visakhapatnamense JA181(T) (97.3 %), Rhodovulum steppense A-20s(T) (97.3 %), Rhodovulum phaeolacus JA580(T) (97 %), Rhodovulum strictum MB-G2(T) (97 %) and other members of the genus Rhodovulum (<97 %). Strain JA756(T) has high sequence similarities with Rhodovulum visakhapatnamense JA181(T) (99.8 %), Rhodovulum sulfidophilum Hansen W4(T) (99.1 %), Rhodovulum kholense JA297(T) (97.9 %) and other members of the genus Rhodovulum (<97 %). The sequence similarity between strains JA746(T) and JA756(T) was 97.5 %. However, these strains are not closely related to each other or to their phylogenetic neighbours since the DNA-DNA reassociation values were less than 56 %. The genomic information was also supported by phenotypic and chemotaxonomic results, leading us to classify strains JA746(T) ( = NBRC 108898(T) = KCTC 15180(T)) and JA756(T) ( = NBRC 109122(T) = KCTC 15223(T)) as the type strains of two novel species of the genus Rhodovulum, for which the names Rhodovulum salis sp. nov. and Rhodovulum viride sp. nov. are proposed, respectively.

Draft genome sequence of Rhodovulum sp. strain PH10, a phototrophic alphaproteobacterium isolated from a soil sample of mangrove of Namkhana, India.

We report the 4.8-Mb draft genome of Rhodovulum sp. strain PH10, a phototrophic bacterium belonging to class Alphaproteobacteria, isolated from a soil sample collected from the mangrove forest of Namkhana in India. This genome is the first from the genus Rhodovulum and will lead to a better understanding of the genes/pathways involved in activities like phototrophic growth and nitrogen fixation in this group of bacteria.

Rhodovulum tesquicola sp. nov., a haloalkaliphilic purple non-sulfur bacterium from brackish steppe soda lakes.

Two strains of purple non-sulfur bacteria (A-36s(T) and A-51s) were isolated from brackish steppe soda lakes of southern Siberia. Genetically, the isolates were related most closely to the type strains of Rhodovulum steppense and Rhodovulum strictum, from which they differed at the species level (98.5% 16S rRNA gene sequence similarity, 40-53% DNA-DNA relatedness). Cells of the two strains were ovoid to rod-shaped, 0.4-0.8 µm wide and 1.0-2.5 µm long, and motile by means of a polar flagellum. They contained internal photosynthetic membranes of vesicular type and photosynthetic pigments (bacteriochlorophyll a and carotenoids of the spheroidene series). The strains were obligate haloalkaliphiles, growing over wide ranges of salinity (0.3-10.0% NaCl) and pH (7.5-10.0), with growth optima at 1.0-3.0% NaCl and pH 8.5-9.0. Photoheterotrophic and chemoheterotrophic growth occurred with a number of organic compounds and biotin, p-aminobenzoate, thiamine and niacin as growth factors. No anaerobic respiration on nitrite, nitrate or fumarate and no fermentation were demonstrated. The strains grew photolithoautotrophically and chemolithoautotrophically with sulfide, sulfur and thiosulfate, oxidizing them to sulfate. Sulfide was oxidized via deposition of extracellular elemental sulfur. No growth with H(2) as the electron donor was observed. The major fatty acid was C(18:1) (78%). The major quinone was ubiquinone Q-10. The DNA G+C content of strain A-36s(T) was 65.4 mol% (T(m)). According to genotypic and phenotypic characteristics, the investigated strains were assigned to a novel species of the genus Rhodovulum, for which the name Rhodovulum tesquicola sp. nov. is proposed. The type strain is A-36s(T) ( = VKM B-2491(T) = ATCC BAA-1573(T)), which was isolated from steppe soda lake Sul'fatnoe (Zabaikal'skii Krai, southern Siberia, Russia).

Rhodovulum bhavnagarense sp. nov., a phototrophic alphaproteobacterium isolated from a pink pond.

An oval to rod-shaped, Gram-stain-negative, phototrophic bacterium, strain JA738(T), was isolated from a sediment sample collected from a pink pond. Strain JA738(T) was non-motile and had vesicular-type intracellular photosynthetic membranes. Bacteriochlorophyll a and carotenoids of the spheroidene series were present as the major photosynthetic pigments. Strain JA738(T) required thiamine and pantothenate for growth. The major cellular fatty acids were C(18 : 1)ω7c, C(18 : 1)ω5c, C(18 : 0) and C(18 : 1)ω7c11-methyl; minor amounts of C(10 : 0) 3-OH and C(16 : 0) were also present. The major quinone was Q-10 and major polar lipids were phosphatidylglycerol, phosphatidylethanolamine and two unidentified sulfolipids (SL1-2). Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA738(T) clustered with species of the genus Rhodovulum in the class Alphaproteobacteria. Strain JA738(T) was most closely related to Rhodovulum adriaticum DSM 2781(T) (96.4 % 16S rRNA gene sequence similarity) and other members of the genus Rhodovulum (<96.1 %). On the basis of phenotypic and molecular genetic evidence, it is proposed that strain JA738(T) should be classified as a novel species of the genus Rhodovulum for which the name Rhodovulum bhavnagarense sp. nov. is proposed. The type strain is JA738(T) ( = DSM 24766(T) = KCTC 15110(T)).

Rhodovulum phaeolacus sp. nov. a phototrophic alphaproteobacterium isolated from a brown pond.

Two strains of oval-rod shaped, Gram-negative, phototrophic, purple non-sulfur bacteria designated JA580(T) and JA595 were isolated from a sediment sample collected from a brown pond. Strain JA580(T) was designated as the type strain, while strain JA595 as an additional strain has similar characteristics to the type strain. Strain JA580(T) was non-motile and grew photoheterotrophically with a number of organic compounds serving as carbon source/electron donor. Intracellular photosynthetic membranes were of the vesicular type. Bacteriochlorophyll a and carotenoids of the spheroidene series were present as the major photosynthetic pigments. Strain JA580(T) requires yeast extract for growth. Strain JA580(T) has an obligate requirement for sulfide or thiosulfate for growth. C(18:1)ω7c, C(18:0), C(18:1)ω9c were the predominant components of cellular fatty acids. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA580(T) clustered with species of the genus Rhodovulum of the family Rhodobacteraceae and is most closely related to the type strains of Rhodovulum adriaticum, Rhodovulum iodosum (96.5%), Rhodovulum robiginosum (96%), Rhodovulum imhoffii (95.6%) and other members of the genus Rhodovulum (<95%). On the basis of phenotypic and molecular genetic evidence, it is proposed that strain JA580(T) should be classified as a novel species of the genus Rhodovulum of the family Rhodobacteraceae, with the species name Rhodovulum phaeolacus sp. nov. The type strain of the species is JA580(T) (=NBRC 107612(T) =KCTC 5963(T)).

Rhodovulum steppense sp. nov., an obligately haloalkaliphilic purple nonsulfur bacterium widespread in saline soda lakes of Central Asia.

Seven strains of purple nonsulfur bacteria isolated from the shallow-water steppe soda lakes of the cryoarid zone of Central Asia formed a genetically homogeneous group within the genus Rhodovulum. The isolates were most closely related to Rhodovulum strictum, from which they differed at the species level (99.5 % 16S rRNA gene identity and 42-44 % DNA-DNA hybridization level). According to genotypic and phenotypic characteristics, the strains were assigned to a new species of the genus Rhodovulum, for which the name Rhodovulum steppense sp. nov. is proposed. Cells of all strains were ovoid to rod-shaped, 0.3-0.8 microm wide and 1-2.5 microm long, and motile by means of polar flagella. They contained internal photosynthetic membranes of the vesicular type and photosynthetic pigments (bacteriochlorophyll a and carotenoids of the spheroidene series). All strains were obligate haloalkaliphiles, growing within a wide range of salinity (0.3-10 %) and pH (7.5-10), with growth optima at 1-5 % NaCl and pH 8.5. Photo- and chemoheterotrophic growth occurred with a number of organic compounds and biotin, thiamine and niacin as growth factors. No anaerobic respiration on nitrite, nitrate or fumarate and no fermentation was demonstrated. Bacteria grew photo- and chemolithoautotrophically with sulfide, sulfur and thiosulfate, oxidizing them to sulfate. Sulfide was oxidized via deposition of extracellular elemental sulfur. No growth with H(2) as electron donor was demonstrated. The major fatty acid was 18 : 1 (81.0 %). The major quinone was Q-10. The DNA G+C content was 66.1 mol% (T(m)). The type strain, A-20s(T) (=VKM B-2489(T) =DSM 21153(T)), was isolated from soda lake Khilganta (Zabaikal'skii Krai, southern Siberia, Russia).

Rhodovulum kholense sp. nov.

A yellowish brown bacterium was isolated from photoheterotrophic enrichment cultures obtained from a mud sample collected from a mangrove forest located in Khola, India. Enrichment and isolation in medium containing 2 % NaCl (w/v) yielded strain JA297(T), cells of which were ovoid and motile. Cells of strain JA297(T) contained vesicular internal membranes and bacteriochlorophyll a and carotenoids of the spheroidene series. Strain JA297(T) grew optimally at 30 degrees C and at pH 6.0-7.0. Photo-organoheterotrophy was the preferred mode of growth. Strain JA297(T) was also able to grow photolithoautotrophically and chemo-organotrophically but not by chemolithoautotrophy or by fermentation. Strain JA297(T) was able to utilize sulfide, sulfite, sulfate, thiosulfate, thioglycolate and cysteine as sulfur sources. Biotin, niacin and thiamine were required as growth factors. On the basis of 16S rRNA gene sequence analysis, strain JA297(T) was shown to belong to the class Alphaproteobacteria and was closely related to the type strains of Rhodovulum marinum (96.72 % similarity), Rhodovulum visakhapatnamense (96.42 %) and Rhodovulum sulfidophilum (96.32 %). The DNA G+C composition was 63 mol%. Based on 16S rRNA gene sequence analysis and morphological and physiological characteristics, strain JA297(T) could be distinguished from all recognized species of the genus Rhodovulum. This strain is therefore suggested to represent a novel species of the genus Rhodovulum, for which the name Rhodovulum kholense sp. nov. is proposed. The type strain is JA297(T) (=ATCC BAA-1544(T)=JCM 14888(T)=CCUG 55397(T)).

Rhodovulum visakhapatnamense sp. nov.

A Gram-negative, rod-shaped, phototrophic bacterium (JA181(T)) was isolated from a tidal water sample. On the basis of 16S rRNA gene sequence similarity, strain JA181(T) was shown to belong to the class Alphaproteobacteria, most closely related to Rhodovulum sulfidophilum (97.8 % similarity to the type strain), Rhodovulum adriaticum (93 %), Rhodovulum robiginosum (93 %), Rhodovulum iodosum (94 %), Rhodovulum imhoffii (94 %), Rhodovulum strictum (95 %), Rhodovulum euryhalinum (94.6 %) and Rhodovulum marinum (94.6 %). DNA-DNA hybridization with Rdv. sulfidophilum DSM 1374(T) (relatedness of 39 % with strain JA181(T)) and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain JA181(T) from the eight Rhodovulum species with validly published names. Strain JA181(T) therefore represents a novel species, for which the name Rhodovulum visakhapatnamense sp. nov. is proposed (type strain JA181(T) =JCM 13531(T) =ATCC BAA-1274(T) =DSM 17937(T)).

Rhodovulum imhoffii sp. nov.

A yellowish-brown bacterium was isolated from photoheterotrophic enrichment cultures obtained from water samples of an aquaculture pond at Bhimunipatnam, India. Enrichment and isolation in a medium containing 2 % NaCl (w/v) yielded strain JA125T, the cells of which were rod-shaped and non-motile. On the basis of the 16S rRNA gene sequence, strain JA125T belongs to the class Alphaproteobacteria and is closely related to the type strains of Rhodovulum iodosum (96 %), Rhodovulum adriaticum (95 %), Rhodovulum robiginosum (95 %), Rhodovulum sulfidophilum (94 %) and Rhodovulum marinum (94 %). The cells of strain JA125T contained vesicular internal membranes and bacteriochlorophyll a and carotenoids of the spheroidene series. Strain JA125T grew optimally at 28 degrees C and at pH 7.0-8.0. The best growth occurred photoheterotrophically with a number of organic compounds serving as carbon sources and electron donors. The strain grew photoautotrophically, but chemoautotrophic growth did not occur. Strain JA125T was able to utilize sulfide, sulfate, thiosulfate and thioglycolate as sulfur sources. Biotin was required as a growth factor. The DNA G+C content was 58 mol%. On the basis of 16S rRNA gene sequence analysis and the morphological and physiological data, strain JA125T is significantly different from other species of the genus Rhodovulum and represents a novel species, for which the name Rhodovulum imhoffii sp. nov. is proposed. The type strain is JA125T (=JCM 13589T=DSM 18064T).

Rhodovulum marinum sp. nov., a novel phototrophic purple non-sulfur alphaproteobacterium from marine tides of Visakhapatnam, India.

A yellowish-brown bacterium was isolated from enrichment cultures inoculated with seawater samples from the eastern coast of India (Visakhapatnam) under photoheterotrophic conditions. Enrichment and isolation in a medium containing 2 % NaCl (w/v) yielded strain JA128(T), which has ovoid to rod-shaped cells, also forms chains and is non-motile. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA128(T) clusters with the Alphaproteobacteria and the sequence similarity with its closest relatives, Rhodovulum iodosum and Rhodovulum sulfidophilum, was 95 %. Strain JA128(T) contained vesicular intracytoplasmic membranes, bacteriochlorophyll a and carotenoids of the spheroidene series. Strain JA128(T) was mesophilic, slightly acidophilic, slightly halophilic and grew photoheterotrophically with a number of organic compounds as carbon source and electron donor. It was unable to grow photoautotrophically, chemoautotrophically or by fermentative modes. It did not utilize sulfide, thiosulfate or hydrogen as electron donors. Thiamine was required as a growth factor. Based on the 16S rRNA gene sequence analysis, morphological and physiological characteristics, strain JA128(T) was significantly different from other species of the genus Rhodovulum and was recognized as a novel species for which the name Rhodovulum marinum sp. nov. is proposed. The type strain is JA128(T) (=ATCC BAA 1215(T)=CCUG 52183(T)=JCM 13300(T)).