Gibbsiella greigii sp. nov., a novel species associated with oak decline in the USA

In 2010, cream-coloured, Gram-negative staining, facultatively anaerobic enterobacteria were isolated from a single black oak tree (Quercus kelloggii) exhibiting decline symptoms in southern California, USA. These 12 isolates were tentatively identified as Gibbsiella quercinecans based on partial gyrB sequencing. Closer examination of the strains using multilocus sequence analysis, based on partial sequences of gyrB, rpoB, infB and atpD genes, and almost complete 16S rRNA gene sequencing suggested that the isolates belong to a novel taxon within the genus Gibbsiella with G. quercinecans as their closest phylogenetic relative. DNA–DNA relatedness studies confirmed that the strains belong to a single taxon in Gibbsiella, which can be differentiated from other members of the genus by several phenotypic traits. Therefore, the name Gibbsiella greigii sp. nov. is proposed for this novel species isolated from symptomatic Q. kelloggii in the USA with FRB 224^T (=LMG 27716^T = NCPPB 4583^T) as the type strain.     

Rahnella victoriana sp. nov., Rahnella bruchi sp. nov., Rahnella woolbedingensis sp. nov., classification of Rahnella genomospecies 2 and 3 as Rahnella variigena sp. nov. and Rahnella inusitata sp. nov., respectively and emended description of the genus Rahnella

Isolations from oak symptomatic of Acute Oak Decline, alder and walnut log tissue, and buprestid beetles in 2009–2012 yielded 32 Gram-negative bacterial strains showing highest gyrB sequence similarity to Rahnella aquatilis and Ewingella americana. Multilocus sequence analysis (using partial gyrB, rpoB, infB and atpD gene sequences) delineated the strains into six MLSA groups. Two MLSA groups contained reference strains of Rahnella genomospecies 2 and 3, three groups clustered within the Rahnella clade with no known type or reference strains and the last group contained the type strain of E. americana. DNA–DNA relatedness assays using both the microplate and fluorometric methods, confirmed that each of the five Rahnella MLSA groups formed separate taxa. Rahnella genomospecies 2 and 3 were previously not formally described due to a lack of distinguishing phenotypic characteristics. In the present study, all five Rahnella MLSA groups were phenotypically differentiated from each other and from R. aquatilis. Therefore we propose to classify the strains from symptomatic oak, alder and walnut and buprestid beetles as: Rahnella victoriana sp. nov. (type strain FRB 225^T = LMG 27717^T = DSM 27397^T), Rahnella variigena sp. nov. (previously Rahnella genomosp. 2, type strain CIP 105588^T = LMG 27711^T), Rahnella inusitata sp. nov. (previously Rahnella genomosp. 3, type strain DSM 30078^T = LMG 2640^T), Rahnella bruchi sp. nov. (type strain FRB 226^T = LMG 27718^T = DSM 27398^T) and Rahnella woolbedingensis sp. nov. (type strain FRB 227^T = LMG 27719^T = DSM 27399^T).     

Description of Brenneria roseae sp. nov. and two subspecies, Brenneria roseae subspecies roseae ssp. nov and Brenneria roseae subspecies americana ssp. nov. isolated from symptomatic oak

Gram-negative, facultatively anaerobic bacteria were isolated from symptomatic oak tissue in the UK and USA. Partial gyrB sequencing placed ten strains in the genus Brenneria, with B. goodwinii as the closest phylogenetic relative. The strains were investigated further using a polyphasic approach including MLSA (based on partial gyrB, rpoB, infB and atpD gene sequences), 16S rRNA gene sequencing, DNA–DNA relatedness studies and both phenotypic and chemotaxonomic assays. The MLSA and 16S rRNA gene analyses separated the strains into two groups based on origin, suggesting that they belong to Brenneria as two novel species. However, the DNA–DNA relatedness values revealed a closer relationship between the groups and indicated that they should belong to the same species. As the two groups of strains from the UK and USA can be differentiated from each other phenotypically and by ERIC PCR fingerprints, it is proposed to classify them as novel subspecies of a novel Brenneria species. The name Brenneria roseae sp. nov. (FRB 222^T = LMG 27714^T = NCPPB 4581^T) is proposed, with Brenneria roseae subsp. roseae ssp. nov. (FRB 222^T = LMG 27714^T = NCPPB 4581^T) for the strains from the UK and Brenneria roseae subsp. americana ssp. nov. (FRB 223^T = LMG 27715^T = NCPPB 4582^T) for the strains from the USA.     

Defluviimonas denitrificans gen. nov., sp. nov., and Pararhodobacter aggregans gen. nov., sp. nov., non-phototrophic Rhodobacteraceae from the biofilter of a marine aquaculture

Three Gram-negative bacterial strains were isolated from the biofilter of a recirculating marine aquaculture. They were non-pigmented rods, mesophiles, moderately halophilic, and showed chemo-organoheterotrophic growth on various sugars, fatty acids, and amino acids, with oxygen as electron acceptor; strains D9-3^T and D11-58 were in addition able to denitrify. Phototrophic or fermentative growth could not be demonstrated. Phylogenetic analysis of the 16S rRNA gene sequences placed D9-3^T and D11-58, and D1-19^T on two distinct branches within the alpha-3 proteobacterial Rhodobacteraceae, affiliated with, but clearly separate from, the genera Rhodobacter, Rhodovulum, and Rhodobaca. Based on morphological, physiological, and 16S rRNA-based phylogenetic characteristics, the isolated strains are proposed as new species of two novel genera, Defluviimonas denitrificans gen. nov., sp. nov. (type strain D9-3^T = DSM 18921^T = ATCC BAA-1447^T; additional strain D11-58 = DSM19039 = ATCC BAA-1448) and Pararhodobacter aggregans gen. nov., sp. nov (type strain D1-19^T = DSM 18938^T = ATCC BAA-1446^T).     

Description of four novel species of Xenorhabdus, family Enterobacteriaceae: Xenorhabdus budapestensis sp. nov., Xenorhabdus ehlersii sp. nov., Xenorhabdus innexi sp. nov., and Xenorhabdus szentirmaii sp. nov

The taxonomic affiliation was determined for four Xenorhabdus strains isolated from four Steinernema hosts from different countries. As compared to the five validly described Xenorhabdus species, i.e., X. nematophila, X. japonica, X. beddingii, X. bovienii and X. poinarii, these isolates represented novel species on the basis of 16S rRNA gene sequences and riboprint patterns, as well as by physiological and metabolic properties. They were named Xenorhabdus budapestensis sp. nov., type strain DSM 16342^T, isolated from Steinernema bicornutum; Xenorhabdus ehlersii sp. nov., type strain DSM 16337^T, isolated from Steinernema serratum; Xenorhabdus innexi sp. nov., type strain DSM 16336^T isolated from Steinernema scapterisci; and Xenorhabdus szentirmaii sp. nov., type strain DSM 16338^T, isolated from Steinernema rarum.     

Chimaereicella alkaliphila gen. nov., sp. nov., a Gram-negative alkaliphilic bacterium isolated from a nonsaline alkaline groundwater

A Gram-negative bacterium designated AC-74(T) was isolated from a highly alkaline groundwater environment (pH 11.4). This organism formed rod-shaped cells, is strictly aerobic, catalase and oxidase positive, tolerates up to 3.0% NaCl, has an optimum growth temperature of 30 degrees C, but no growth occurs at 10 or 40 degrees C, and an optimum pH value of 8.0, but no growth occurs at pH 7.0 or 11.3. The predominant fatty acids are iso-15:0, iso-17:1 omega9c and 16:1 omega7c and or iso-15:2OH. The G+C content of DNA was 43.5mol%. The phylogenetic analyses of the sequences of the 16s RNA genes indicated that strain AC-74(T) belongs to the family "Flexibacteriaceae" and is phylogenetically equidistant ( approximately 94.5%) from the majority of the species of the genus Algoriphagus and from the genus Hongiella. Based on the phylogenetic analyses and distinct phenotypic characteristics, we are of the opinion that strain AC-74(T), represents a new species of the novel genus for which we propose the name Chimaereicella alkaliphila gen. nov., sp. nov.     

Natronolimnobius baerhuensis gen. nov., sp. nov. and Natronolimnobius innermongolicus sp. nov., novel haloalkaliphilic archaea isolated from soda lakes in Inner Mongolia, China

Three novel isolates of haloalkaliphilic archaea, strains IHC-005^T, IHC-010, and N-1311^T, from soda lakes in Inner Mongolia, China, were characterized to elucidate their taxonomic positions. The three strains were aerobic, Gram-negative chemoorganotrophs growing optimally at 37–45°C, pH 9.0–9.5, and 15–20% NaCl. Cells of strains IHC-005^T/IHC-010 were motile rods, while those of strain N-1311^T were non-motile pleomorphic flats or cocci. The three strains contained diphytanyl and phytanyl-sesterterpanyl diether derivatives of phosphatidylglycerol and phosphatidylglycerophosphate methyl ester. No glycolipids were detected. On phylogenetic analysis of 16S rRNA gene sequences, they formed an independent cluster in the Natro group of the family Halobacteriaceae. Comparison of their morphological, physiological, and biochemical properties, DNA G+C content and 16S rRNA gene sequences, and DNA-DNA hybridization study support the view that strains IHC-005^T/IHC-010 and strain N-1311^T represent separate species. Therefore, we propose Natronolimnobius baerhuensis gen. nov., sp. nov. for strains IHC-005^T (=CGMCC 1.3597^T =JCM 12253^T)/IHC-010 (=CGMCC 1.3598=JCM 12254) and Natronolimnobius innermongolicus sp. nov. for N-1311^T (=CGMCC 1.2124^T =JCM 12255^T).     

Enhygromyxa salina gen. nov., sp. nov., a slightly halophilic myxobacterium isolated from the coastal areas of Japan

Six isolates of novel marine myxobacteria, designated strains SHK-1T, SMK-1-1, SMK-1-3, SMK-10, SKK-2, and SMP-6, were obtained from various coastal samples (mud, sands and algae) collected around Japan. All of the isolates had Gram-negative rod-shaped cells, motile by gliding and grew aerobically. They showed bacteriolytic action, fruiting body formation, and NaCl requirement for growth with an optimum concentration of 1.0-2.0% (w/v). In addition, divalent cationic components of seawater, such as Mg2+ or Ca2+, were also needed for growth. The major respiratory quinone was MK-7. The G+C content of genomic DNA ranged from 65.6 to 67.4 mol% (by HPLC). The isolates shared almost identical 16S rDNA sequences, and clustered with a recently described marine myxobacterium, Plesiocystis pacifica, as their closest relative on a phylogenetic tree (95.9-96.0% similarity). Physiological and chemotaxonomic differences between the new strains and strains of the genus Plesiocystis justify the proposal of a new genus. Therefore, we propose to classify the six isolates into a new taxon of marine myxobacteria with the name, Enhygromyxa salina gen. nov., sp. nov. The type strain is SHK-1(T) (JCM 11769(T) = DSM 15217(T) = AJ 110011(T)).     

Redheadia quercus gen. et sp. nov., the teleomorph of Mycopappus quercus, the frosty mildew fungus in Quercus acutissima

The teleomorph of Mycopappus quercus causing frosty mildew in Quercus acutissima is described as a new genus and species, Redheadia quercus, in the Sclerotiniaceae. Apothecia sprout from sclerotia on the fallen infected leaves kept for 10 months at 5°C and subsequent incubation at 15°C under diffused room light. Typical zonate lesions and multicellular propagules of M. quercus are produced on Q. acutissima, by mycelial inoculation using an isolate from a single ascospore, confirming the teleomorph–anamorphic connection. No significant differences are observed between cultured colonies of isolates from the ascospore and those from the propagule. Sclerotia and microconidia of the fungus are produced on culture media.     

Thermosediminibacter oceani gen. nov., sp. nov. and Thermosediminibacter litoriperuensis sp. nov., new anaerobic thermophilic bacteria isolated from Peru Margin

A new group of anaerobic thermophilic bacteria was isolated from enrichment cultures obtained from deep sea sediments of Peru Margin collected during Leg 201 of the Ocean Drilling Program. A total of ten isolates were obtained from cores of 1–2 m below seafloor (mbsf) incubated at 60°C: three isolates came from the sediment 426 m below sea level with a surface temperature of 9°C (Site 1227), one from 252 m below sea level with a temperature of 12°C (Site 1228), and six isolates under sulfate-reducing condition from the lower slope of the Peru Trench (Site 1230). Strain JW/IW-1228P from the Site 1228 and strain JW/YJL-1230-7/2 from the Site 1230 were chosen as representatives of the two identified clades. Based on the 16S rDNA sequence analysis, these isolates represent a novel group with Thermovenabulum and Caldanaerobacter as their closest relatives. The temperature range for growth was 52–76°C with an optimum at around 68°C for JW/IW-1228P and 43–76°C with an optimum at around 64°C for JW/YJL-1230-7/2. The pH^25C range for growth was from 6.3 to 9.3 with an optimum at 7.5 for JW/IW-1228P and from 5 to 9.5 with an optimum at 7.9–8.4 for JW/YJL-1230-7/2. The salinity range for growth was from 0% to 6% (w/v) for JW/IW-1228P and from 0% to 4.5% (w/v) for JW/YJL-1230-7/2. The G+C content of the DNA was 50 mol% for both JW/IW-1228P and JW/YJL-1230-7/2. DNA–DNA hybridization yielded 52% similarity between the two strains. According to 16S rRNA gene sequence analysis, the isolates are located within the family, Thermoanaerobacteriaceae. Based on their morphological and physiological properties and phylogenetic analysis, it is proposed that strain JW/IW-1228P^T is placed into a novel taxa, Thermosediminibacter oceani, gen. nov., sp. nov. (DSM 16646^T=ATCC BAA-1034^T), and JW/YJL-1230-7/2^T into Thermosediminibacter litoriperuensis sp. nov. (DSM 16647^T =ATCC BAA-1035^T).An erratum to this article can be found at     

Neoscardovia arbecensis gen. nov., sp. nov., isolated from porcine slurries

Three Gram-positive, anaerobic, pleomorphic strains (PG10(T), PG18 and PG22), were selected among five strains isolated from pig slurries while searching for host specific bifidobacteria to track the source of fecal pollution in water. Analysis of the 16S rRNA gene sequence showed a maximum identity of 94% to various species of the family Bifidobacteriaceae. However, phylogenetic analyses of 16S rRNA and HSP60 gene sequences revealed a closer relationship of these strains to members of the recently described Aeriscardovia, Parascardovia and Scardovia genera, than to other Bifidobacterium species. The names Neoscardovia gen. nov. and Neoscardovia arbecensis sp. nov. are proposed for a new genus and for the first species belonging to this genus, respectively, and for which PG10(T) (CECT 8111(T), DSM 25737(T)) was designated as the type strain. This new species should be placed in the Bifidobacteriaceae family within the class Actinobacteria, with Aeriscardovia aeriphila being the closest relative. The prevailing cellular fatty acids were C(16:0) and C(18:1)ω9c, and the major polar lipids consisted of a variety of glycolipids, diphosphatidyl glycerol, two unidentified phospholipids, and phosphatidyl glycerol. The peptidoglycan structure was A1γmeso-Dpm-direct. The GenBank accession numbers for the 16S rRNA gene and HSP60 gene sequences of strains PG10(T), PG18 and PG22 are JF519691, JF519693, JQ767128 and JQ767130, JQ767131, JQ767133, respectively.     

Balneomonas flocculans gen. nov., sp. nov., a new cellulose-producing member of the alpha-2 subclass of Proteobacteria

A new bacterial strain capable of producing cellulose was isolated from a hot spring. The isolate was Gram-negative, aerobic, and rod-shaped. The optimum temperature for growth was 40-45 degrees C. Methanol, glucose and other common carbohydrates were not utilized as sole growth substrates. Thiosulfate was not oxidized. The G+C content of the DNA was determined to be 64.0 mol%. Comparative 16S rDNA analysis indicated that Bosea thiooxidans and some strains of the genus Methylobacterium were the nearest relatives. The isolate can be distinguished from these relatives by its defectiveness in methanol utilization and thiosulfate oxidation. On the basis of its phenotypic properties and phylogeny, it is proposed that the isolate be designated Balneomonas flocculans gen. nov., sp. nov. The type strain is TFBT (= JCM 11936T, = KCTC 12101T, = IAM 15034T, = ATCC BAA-817T).     

Arcobacter ellisii sp. nov., isolated from mussels

As part of a study carried out for detecting Arcobacter spp. in shellfish, three mussel isolates that were Gram-negative slightly curved rods, non-spore forming, showed a new 16S rDNA-RFLP pattern with a specific identification method for the species of this genus. Sequences of the 16S rRNA gene and those of the housekeeping genes rpoB, gyrB and hsp60 provided evidence that these mussel strains belonged to an unknown genetic lineage within the genus Arcobacter. The similarity between the 16S rRNA gene sequence of the representative strain (F79-6^T) and type strains of the other Arcobacter species ranged between 94.1% with A. halophilus and 99.1% with the recently proposed species A. defluvii (CECT 7697^T). DDH results between strain F79-6^T and the type strain of the latter species were below 70% (53 ± 3.0%). Phenotypic characteristics together with MALDITOF mass spectra differentiated the new mussel strains from all other Arcobacter species. All the results indicate that these strains represent a new species, for which the name Arcobacter ellisii sp. nov. with the type strain F79-6^T (=CECT 7837^T = LMG 26155^T) is proposed.     

Ponticoccus gilvus gen. nov., sp. nov., a novel member of the family Propionibacteriaceae from seawater

A novel actinobacterium, designated strain MSW-19^T, was isolated from a seawater sample in Republic of Korea. Cells were aerobic, Gram-positive, non-endospore-forming, and non-motile cocci. Colonies were circular, convex, opaque, and vivid yellow in colour. A phylogenetic tree based on 16S rRNA gene sequences exhibited that the organism formed a distinct clade within the radius encompassing representatives of the family Propionibacteriaceae. The phylogenetic neighbors were the type strains of the genera Friedmanniella, Microlunatus, Micropruina, Propionicicella, and Propionicimonas. Levels of 16S rRNA gene sequence similarity between the isolate and members of the family were less than 95.3%. The cell wall peptidoglycan of the organism contained LL-diaminopimelic acid as the diagnostic diamino acid. The isolate contained MK-9(H₄) as the predominant menaquinone, ai-C_15:0 as the major fatty acid and polar lipids including phosphatidylglycerol, phosphatidylethanolamine, and an unknown phospholipid. The G+C content of the DNA was 69.6 mol%. On the basis of the phenotypic and phylogenetic data presented here, the isolate is considered to represent a novel genus and species in the family Propionibacteriaceae, for which the name Ponticoccus gilvus gen. nov., sp. nov. is proposed. The type strain is strain MSW-19^T (= KCTC 19476^T= DSM 21351^T).     

Flavobacterium frigidimaris sp. nov., isolated from Antarctic seawater

We described the polyphasic characterization of the psychrotolerant isolated from Antarctic seawater. The strain was closely related to Flavobacterium hydatis, F. pectinovorum, and F. saccharophilum on the basis of the 16S rDNA sequence analysis. However, DNA–DNA hybridization experiments showed that the DNA-similarities between strain KUC-1^T and the reference strains of Flavobacterium were less than 30%. Therefore, we can definite a new species of Flavobacterium phylogenetically, and strain KUC-1^T can be considered to be a new species of Flavobacterium. i.e. F. frigidimaris (KUC-1^T: JCM 12218^T and DSM 15937^T; mol% G+C of DNA of the type strain is 34.5 mol%). Useful phenotypical features for discrimination of F. frigidimaris from other Flavobacterium species, such as a resistance to NaCl, optimum growth temperature, and cellular fatty acid composition, were also determined.     

Rubrimonas shengliensis sp. nov. and Polymorphum gilvum gen. nov., sp. nov., novel members of Alphaproteobacteria from crude oil contaminated saline soil

Four bacterial strains were isolated from a crude oil contaminated saline soil in Shengli Oilfield, China. Strains SL014B-28A2^T and SL014B-80A1 were most closely related to Rubrimonas cliftonensis OCh 317^T, while strains SL003B-26A1^T and SL003B-26A2 were most closely related to but readily different from the species in the Pannonibacter-Labrenzia-Roseibium-Stappia cluster. The major fatty acids were C_18:1ω7c, C_16:0, C_18:0 and 11-Methyl C_18:1ω7c, and C_18:1ω7c, 11-Methyl C_18:1ω7c and C_18:0, respectively, for these two groups of isolates. Q-10 was the predominant ubiquinone. The G + C contents of genomic DNA of the four isolates were 67.9, 69.7, 65.6 and 65.6 mol%. Based on the polyphasic taxonomic characteristics, strains SL014B-28A2^T and SL014B-80A1 represented a novel species of the genus Rubrimonas, for which the name Rubrimonas shengliensis sp. nov. is proposed, with strain SL014B-28A2^T (=LMG 26072^T = CGMCC 1.9170^T) as the type strain. Isolates SL003B-26A1^T and SL003B-26A2 represented a novel genus and species of the family Rhodobacteraceae, for which the name Polymorphum gilvum gen. nov., sp. nov. is proposed, with strain SL003B-26A1^T (=LMG 25793^T = CGMCC 1.9160^T) as the type strain.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

Spirosymplokos deltaeiberi nov. gen., nov. sp.: variable-diameter composite spirochete from microbial mats

Large (up to 100 m long), loosely coiled, free-living spirochetes with variable diameters (from 0.4 to 3 m in the same cell) were seen at least 40 times between August 1990 and January 1993. These spirochetes were observed in mud water and enrichment media from highly specific habitats in intertidal evaporite flats at three disjunct localities, one in Spain and two in Mexico. All three are sites of commerical saltworks. Associated with Microcoleus chthonoplastes, the large spirochetes from Spain display phototaxis and a composite organization. Shorter and smaller-diameter spirochetes are seen inside both healthy and spent periplasm of larger ones. Small spirochetes attached to large ones have been observed live. From two to twelve spirochete protoplasmic cylinders were seen inside a single common outer membrane. A distinctive granulated cytoplasm in which the granules are of similar diameter (20–32 nm) to that of the flagella (26 nm) was present. Granule diameters were measured in thin section and in negatively-stained whole-mount preparations. Based on their ultrastructure, large size, variable diameter, number of flagella (3 to 6), and phototactic behavior these unique spirochetes are formally named Spirosymplokos deltaeiberi. Under anoxic (or low oxygen) conditions they formed blooms in mixed culture in media selective for spirochetes. Cellobiose was the major carbon source in 80% seawater, the antibiotic rifampicin was added, mat from the original field site was present and tubes were incubated in the light at from 18–31 °C. Within 1–2 weeks populations of the large spirochete developed at 25 °C but they could not be transferred to fresh medium.     

Ectothiorhodosinus mongolicum gen. nov., sp. nov., a New Purple Bacterium from a Soda Lake in Mongolia

A new nonmotile purple sulfur bacterium (strain M9) was isolated from the steppe soda lake Lake Dzun Uldziin Nur (pH 9.4; mineralization, 3.3%) situated in southeastern Mongolia. Individual cells appear as vibrios 0.3–0.5 × 0.7–1 m in size. The dividing cells often do not separate from each other, forming an almost closed ring. The internal photosynthetic membranes are represented by concentric lamellae lining the cell wall. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The main carotenoid (>96%) is spirilloxanthin. Two typical light-harvesting complexes (LH1 and LH2) are present in the membranes in a 1 : 1 ratio. The bacterium is an anaerobe and facultative photoorganoheterotroph. Photolithoautotrophic growth on sulfide is scarce. Thiosulfate is utilized as an electron donor only in the presence of organic matter. Globules of elemental sulfur are formed as an intermediary product of sulfide and thiosulfate oxidation and are deposited outside the cells. The end product of oxidation is sulfate. In the presence of sulfide and carbonates, acetate, lactate, malate, pyruvate, propionate, succinate, and fumarate are used as additional sources of carbon in anoxygenic photosynthesis. Vitamins are not required. The bacterium is an alkaliphile, the pH optimum is at 8.3–9.1, the pH range is 7.6–10.1. The optimum NaCl concentration in the medium is 1 to 7%; the range is 0.5 to 0.9%. The optimum carbonate content in the medium is 2%; the range is 1 to 10%. The best growth occurs at 30–35°C. The DNA G+C content is 57.5 mol %. According to the results of analysis of the 16S rRNA gene sequences, the new isolate M9 belongs to the phylogenetic cluster containing representatives of the family Ectothiorhodospiraceae within the class Gammaproteobacteria. In this class, the new isolate forms a new branch, which occupies an intermediate position between the representatives of the genera Ectothiorhodospira and Thiorhodospira. Based on the phenotypic and genetic characteristics, the new purple sulfur bacterium was assigned to a new species of a new genus of the family Ectothiorhodospiraceae, Ectothiorhodosinus mongolicum gen. nov., sp. nov.