Rhodospirillum salinarum sp. nov., a halophilic photosynthetic bacterium isolated from a Portuguese saltern

A new species of halophilic photosynthetic bacteria, Rhodospirillum salinarum, has been isolated and described. Its natural habitat are the terminal crystallization ponds of solar salt production plants. R. salinarum grows optimally at 42°C in the presence of 6–18% NaCl (w/v). Growth requirements are complex, yeast extract and peptone being required both for aerobic heterotrophic and for anaerobic phototrophic growth. Increasing concentrations of NaCl in the growth media did not give rise to any corresponding increase in intracellular concentrations of K⁺, Na⁺, polyalcohols or amino acids. Malate dehydrogenase from R. salinarum is not halophilic, being inhibited even at low concentrations of Na⁺ or K⁺. The GC mol % of DNA from R. salinarum is markedly higher than that for DNA from R. salexigens, the only previously described halophilic species of the genus Rhodospirillum.     

Rhodospirillum sodomense,sp. nov., a Dead Sea rhodospirillum species

A new species of halophilic anoxygenic purple bacteria of the genus Rhodospirillum is described. The new organism, isolated from water/sediment of the Dead Sea, was vibrio-shaped and an obligate halophile. Growth was best at 12% NaCl, with only weak growth occurring at 6% or 21% NaCl. Growth occurred at Mg²⁺ concentrations up to 1 M but optimal growth was obtained at 0.05–0.1 M Mg²⁺. Bromide was well tolerated as an alternative anion to chloride. The new organism is an obligate phototroph, growing photoheterotrophically in media containing yeast extract and acetate or a few other organic compounds. Growth of the Dead Sea Rhodospirillum species under optimal culture conditions was slow (minimum t_d 20 h). Cells contained bacteriochlorophyll a and carotenoids of the spirilloxanthin series and mass cultures were pink in color. Absorption spectra revealed the presence of a B875 (light-harvesting I) but no B800/B850 (light-harvesting II) photopigment complex. The new organism shares a number of properties with the previously described halophilic phototrophic bacterium Rhodospirillum salinarum and was shown to be related to this phototroph by 16S rRNA sequencing. However, because of its salinity requirements, photosynthetic properties, and isolation from the Dead Sea, the new phototroph is proposed as a new species of the genus Rhodospirillum, R. sodomense.     

Desulfomonile tiedjei gen. nov. and sp. nov., a novel anaerobic,dehalogenating, sulfate-reducing bacterium

An anaerobic, dehalogenating, sulfate-reducing bacterium, strain DCB-1, is described and nutritionally characterized. The bacterium is a Gram-negative, nonmotile, non-sporeforming large rod with an unusual morphological feature which resembles a collar. The microorganism reductively dehalogenates meta substituted halobenzoates and also reduces sulfate, sulfite and thiosulfate as electron acceptors. The bacterium requires nicotinamide, 1,4-naphthoquinone and thiamine for optimal growth in a defined medium. The microorganism can grow autotrophically on H₂:CO₂ with sulfate or thiosulfate as terminal electron acceptors. It can also grow heterotrophically with pyruvate, several methoxybenzoates, formate plus sulfate or benzoate plus sulfate. It ferments pyruvate to acetate and lactate in the absence of other electron acceptors. The bacterium is inhibited by MoO _inf4 ^sup2- or SeO _inf4 ^sup2- as well as tetracycline, chloramphenicol, kanamycin or streptomycin. Cytochrome c₃ and desulfoviridin have been purified from cells grown in defined medium. 16S rRNA sequence analysis indicates the organism is a new genus of sulfate-reducing bacteria in the delta subdivision of the class Proteobacteria. We propose that the strain be named Desulfomonile tiedjei.Non-standard abbreviations PIPES piperazine-N,N-bis[2-ethanesulfonic acid] - MES 2-[N-morpholino]ethanesulfonic acid - TES N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid - HQNO 2-N-heptyl-4-hydroxy-quinoline-N-oxide - CCCP carbonyl-cyanide-m-chlorophenylhydrazine - CM carboxymethyl     

Cytophaga xylanolytica sp. nov., a xylan-degrading,anaerobic gliding bacterium

Gliding bacteria attached in masses to, and dominated the fermentation of, xylan powder in methanogenic and sulfidogenic enrichments from various freshwater sediments. Isolates of such bacteria were all gram-negative, slender rods (0.4×4-24 m) that formed no endospores, microcysts or fruiting bodies. Representative strain XM3 was a mesophilic, aeroduric anaerobe that grew by fermentation of mono-, di-, and poly-saccharides (but not cellulose) in a mineral medium containing up to 3% NaCl. However, CO₂/HCO _inf3 ^sup- was required in media for consistent initiation of growth. Fermentation products included acetate, propionate, succinate, CO₂, and H₂. Xylan-grown cells had xylanase and various glycosidase activities that were mainly or almost entirely cell-associated, respectively. Strain XM3 was weakly catalase positive, but oxidase negative; it possessed sulphonolipids and carotenoid, but not flexirubin, pigments; and its total cellular fatty acids were dominated by C_15:0 anteiso (75%), n (13%) and iso (2%) isomers. Strain XM3 had 45.5 mol% G+C in its DNA, and partial sequencing of its 16S rRNA placed XM3 within the Bacteroides-Flavobacterium phylogenetic group. Similar strains were isolated from marine sediments. Strain XM3 is herewith proposed as the type strain of the new species, Cytophaga xylanolytica. Results, which are discussed in terms of our current concept of the genus Cytophaga, suggest that the importance of C. xylanolytica in anaerobic biopolymer decomposition has not been fully appreciated.Dedicated to Professor Norbert Pfennig, in whose laboratory this project was initiated and who recently retired after more than four decades of contributions to microbiology     

Salimicrobium salexigens sp. nov., a moderately halophilic bacterium from salted hides

Two Gram-positive, moderately halophilic bacteria, designated strains 29CMI^T and 53CMI, were isolated from salted hides. Both strains were non-motile, strictly aerobic cocci, growing in the presence of 3–25% (w/v) NaCl (optimal growth at 7.5–12.5% [w/v] NaCl), between pH 5.0 and 10.0 (optimal growth at pH 7.5) and at temperatures between 15 and 40 °C (optimal growth at 37 °C). Phylogenetic analysis based on 16S rRNA gene sequence comparison showed that both strains showed a similarity of 98.7% and were closely related to species of the genus Salimicrobium, within the phylum Firmicutes. Strains 29CMI^T and 53CMI exhibited 16S rRNA gene sequence similarity values of 97.9–97.6% with Salimicrobium album DSM 20748^T, Salimicrobium halophilum DSM 4771^T, Salimicrobium flavidum ISL-25^T and Salimicrobium luteum BY-5^T. The DNA G+C content was 50.7 mol% and 51.5 mol% for strains 29CMI^T and 53CMI, respectively. The DNA–DNA hybridization between both strains was 98%, whereas the values between strain 29CMI^T and the species S. album CCM 3517^T, S. luteum BY-5^T, S. flavidum ISL-25^T and S. halophilum CCM 4074^T were 45%, 28%, 15% and 10%, respectively, showing unequivocally that strains 29CMI^T and 53CMI constitute a new genospecies. The major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0, iso-C_15:0 and iso-C_14:0. The main respiratory isoprenoid quinone was MK-7, although small amounts of MK-6 were also found. The polar lipids of the type strain consist of diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and one glycolipid. The peptidoglycan type is A1γ, with meso-diaminopimelic acid as the diagnostic diamino acid. On the basis of the phylogenetic analysis, and phenotypic, genotypic and chemotaxonomic characteristics, we propose strains 29CMI^T and 53CMI as a novel species of the genus Salimicrobium, with the name Salimicrobium salexigens sp. nov. The type strain is 29CMI^T (=CECT 7568^T = JCM 16414^T = LMG 25386^T).     

Thiocapsa halophila sp. nov., a new halophilic phototrophic purple sulfur bacterium

A new phototrophic sulfur bacterium has been isolated from a red layer in a laminated mat occurring underneath a gypsum crust in the mediterranean salterns of Salin-de-Giraud (Camargue, France). Single cells were coccus-shaped, non motile, without gas vacuoles and contained sulfur globules. Bacteriochlorophyll a and okenone were present as major photosynthetic pigments. These properties and the G+C content of DNA (65.9–66.6 mol% G+C) are typical characteristics of the genus Thiocapsa. However, the new isolate differs from known species in the genus, particularly in NaCl requirement (optimum, 7% NaCl; range, 3–20% NaCl) and some physiological characteristics. Therefore, a new species is proposed, Thiocapsa halophila, sp. nov.Dedicated to Prof. Dr. Norbert Pfennig in occasion of his 65th birthday     

Ectothiorhodospira halochloris sp. nov., a new extremely halophilic phototrophic bacterium containing bacteriochlorophyll b

A new bacteriochlorophyll b containing phototrophic bacterium was isolated from extremely saline and alkaline soda lakes in Egypt. Enrichment and isolation were performed using a synthetic medium with high contents of sodium carbonate, sodium sulfate and sodium chloride. Photoautotrophic growth occurred with hydrogen sulfide as photosynthetic electron donor. During oxidation of sulfide to sulfate extracellular elemental sulfur globules appeared in the medium. Cells were also capable to grow under photoheterotrophic conditions with acetate, propionate, pyruvate, succinate, fumarate or malate as carbon sources and electron donors. Under these conditions sulfate was assimilated. Optimal growth under the applied experimental conditions occurred at a total salinity of 14–27%, a pH-range between 8.1 and 9.1 and a temperature between 47°C and 50°C. The cells were 0.5–0.6 m wide and, depending on cultural conditions, 2.5–8.0 m long; they were spiral shaped, multiplied by binary fission and were motile by means of bipolar flagella. Intercytoplasmic photosynthetic membranes were present as stacks. Bacteriochlorophyll b was the main photosynthetic pigment; small amounts of carotenoids were mainly present as glucosides of rhodopin and its methoxy derivative. The new organism is described as Ectothiorhodospira halochloris.Dedicated to Professor C. B. van Niel on the occasion of his 80th birthday     

Treponema succinifaciens sp. nov., an anaerobic spirochete from the swine intestine

The morphology, the general physiological characteristics, and the energy-yielding metabolism of an obligately anaerobic spirochete isolated from the colon of a swine were studied. Electron microscopy showed that the helical spirochetal cells possessed an outer sheath, a protoplasmic cylinder, and 4 periplasmic fibrils in a 2-4-2 arrangement. The spirochete grew in an atmosphere of N₂ in prereduced media containing a carbohydrate, NaHCO₃, rumen fluid, yeast extract, peptone, l-cysteine, and inorganic salts. The spirochete fermented carbohydrates and required substrate amounts of CO₂ (HCO ₃ ^- ) for growth. Amino acids were not fermented. Major fermentation products of cells growing with glucose as the substrate and in the presence of CO₂ were acetate, formate, succinate, and lactate. Small amounts of 2,3-butanediol, pyruvate, and acetoin were also formed. Determinations of enzymatic activities in cell extracts, and of radioactivity in products formed by growing cells from [1-¹⁴C]glucose, indicated that this sugar was dissimilated to pyruvate via the Embden-Meyerhof pathway. The spirochetes used a coliform-type clastic reaction to metabolize pyruvate. Determinations of radioactivity in products formed from [¹⁴C]NaHCO₃ indicated that CO₂ was assimilated and used in succinate production. The guanine+cytosine content of the DNA was 36 mol%. This study indicates that this intestinal spirochete represents a new species of Treponema. It is proposed that the new species be named Treponema succinifaciens.Abbreviations cpm counts per minute - DTT dithiothreitol - EM Embden-Meyerhof - GC guanine plus cytosine - IgG immunoglobulin G - PC protoplasmic cylinder - PF periplasmic fibrils (axial fibrils) - OS outer sheath     

Ectothiorhodospira vacuolata sp. nov., a new phototrophic bacterium from soda lakes

A new phototrophic bacterium was isolated from Jordanian and Kenyan alkaline salt lakes. Cells are rod shaped, 1.5 m wide and 2–4 m long, and motile by polar flagella. They divide by binary fission, and possess photosynthetic membranes as lamellar stacks similar to those in the other species of the genus Ectothiorhodospira and the brown colored Rhodospirillum species. The presence of bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series is indicated by the absorption spectra of living cells. Under certain growth conditions the cells form gas vacuoles, may become immotile and float to the top of the culture medium. Sulfide and thiosulfate are used as photosynthetic electron donors. During the oxidation of sulfide to sulfate, elemental sulfur is formed, which is accumulated outside the cells. The organisms are strictly anaerobic, do not require vitamins, are moderately halophilic and need alkaline pH-values for growth. The new species Ectothiorhodospira vacuolata is proposed.     

Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov., a novel zeaxanthin-producing marine bacterium of the family Flavobacteriaceae

A novel strictly aerobic, gliding, Gram-negative, rod-shaped, halo- and mesophilic bacterium (TD-ZX30(T)) was isolated from a seawater sample collected on the Pacific coastline of Japan near Kamakura City (Fujisawa, Kanagawa). The temperature range for growth of TD-ZX30(T) was between 16 and 44 degrees C. The DNA G+C content was 32.0mol%. The predominant fatty acids were iso-C(15:1) G, iso-C(15:0), iso-C(16:0) 3-OH, iso-C(15:0) 3-OH, Summed feature (iso-C(15:0) 2-OH and/or C(16:1)omega7c), iso-C(17:0) 3-OH, and C(15:0). MK-6 was the only respiratory quinone. Zeaxanthin was the major carotenoid pigment produced but flexirubin-type pigments were not produced. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that TD-ZX30(T) belonged to a distinct lineage in the family Flavobacteriaceae, sharing 93.9% sequence similarity with the nearest species Olleya marilimosa. TD-ZX30(T) could be distinguished from the other members of the family Flavobacteriaceae by a number of chemotaxonomic and phenotypic characteristics. The results of polyphasic taxonomic analyses suggested that TD-ZX30(T) represents a novel genus and a novel species, for which the name Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov. is proposed. The type strain is TD-ZX30(T) (=NBRC 102119=CCUG 53614=DSM 18436).     

Heliothrix oregonensis,gen. nov., sp. nov., a phototrophic filamentous gliding bacterium containing bacteriochlorophyll a

An unusual filamentous, gliding bacterium was found in a few hot springs in Oregon where it formed a nearly unispecific top layer of microbial mats. It contained a bacteriochlorophyll a-like pigment and an abundance of carotenoids. There were no chlorosomes or additional chlorophylls. The organism was aerotolerant and appeared to be photoheterotrophic. It was successfully co-cultured with an aerobic chemoheterotroph in a medium containing glucose and casamino acids. Although it has many characteristics in common with the genus Chloroflexus, the lack of chlorosomes and bacteriochlorophyll c and the aerobic nature of this organism indicate that it should be placed in a new genus. This conclusion is supported by 5S rRNA nucleotide sequence data.     

Holophaga foetida gen. nov., sp. nov., a new,homoacetogenic bacterium degrading methoxylated aromatic compounds

A polyphasic approach was used in which genotypic and phenotypic properties of a gram-negative, obligately anaerobic, rod-shaped bacterium isolated from a black anoxic freshwater mud sample were determined. Based on these results, the name Holophaga foetida gen. nov., sp. nov. is proposed. This microorganism produced dimethylsulfide and methanethiol during growth on trimethoxybenzoate or syringate. The only other compounds utilized were pyruvate and trihydroxybenzenes such as gallate, phloroglucinol, or pyrogallol. The aromatic compounds were degraded to acetate. Although comparison of the signature nucleotide pattern of the five established subclasses of Proteobacteria with the 16S rDNA sequence of Holophaga foetida revealed a relationship to members of the -subclass, the phylogenetic position within the radiation of this class is so deep and dependent upon the number and selection of reference sequences that its affiliation to the Proteobacteria must be considered tentative. The type strain is H. foetida strain TMBS4 (DSM 6591).F. Bak died on 27 December 1992. A very promising and productive career thus ended much too early     

New types of acetate-oxidizing,sulfate-reducing Desulfobacter species,D. hydrogenophilus sp. nov., D. latus sp. nov., and D. curvatus sp. nov.

Sulfate-reducing bacteria with oval to rod-shaped cells (strains AcRS1, AcRS2) and vibrio-shaped cells (strains AcRM3, AcRM4, AcRM5) differing by size were isolated from anaerobic marine sediment with acetate as the only electron donor. A vibrio-shaped type (strain AcKo) was also isolated from freshwater sediment. Two strains (AcRS1, AcRM3) used ethanol and pyruvate in addition to acetate, and one strain (AcRS1) grew autotrophically with H₂, sulfate and CO₂. Higher fatty acids or lactate were never utilized. All isolates were able to grow in ammonia-free medium in the presence of N₂. Nitrogenase activity under such conditions was demonstrated by the acetylene reduction test. The facultatively lithoautotrophic strain (AcRS1), a strain (AcRS2) with unusually large cells (2×5 m), and a vibrio-shaped strain (AcRM3) are described as new Desulfobacter species, D. hydrogenophilus, D. latus, and D. curvatus, respectively.     

Rhodospirillum salexigens,spec. nov., an obligatory halophilic phototrophic bacterium

The name Rhodospirillum salexigens, spec. nov., was proposed for the strain WS 68, isolated by W. R. Sistrom at the Oregon coast from salt water. The spiral-shaped phototrophically or chemotrophically growing, salt demanding bacterium contains intracytoplasmic membranes arranged parallel to the cytoplasmic membrane. Bacteriochlorophyll a and spirilloxanthin are the major pigments. Growth occurs between 20 and 45°C at a neutral pH. The DNA base composition was 64 mol % guanine plus cytosine. The cell wall contains peptidoglycan and proteins but no glycolipids.     

Alkaliflexus imshenetskii gen. nov. sp. nov., a new alkaliphilic gliding carbohydrate-fermenting bacterium with propionate formation from a soda lake

Anaerobic saccharolytic bacteria thriving at high pH values were studied in a cellulose-degrading enrichment culture originating from the alkaline lake, Verkhneye Beloye (Central Asia). In situ hybridization of the enrichment culture with 16S rRNA-targeted probes revealed that abundant, long, thin, rod-shaped cells were related to Cytophaga. Bacteria of this type were isolated with cellobiose and five isolates were characterized. Isolates were thin, flexible, gliding rods. They formed a spherical cyst-like structure at one cell end during the late growth phase. The pH range for growth was 7.5–10.2, with an optimum around pH 8.5. Cultures produced a pinkish pigment tentatively identified as a carotenoid. Isolates did not degrade cellulose, indicating that they utilized soluble products formed by so far uncultured hydrolytic cellulose degraders. Besides cellobiose, the isolates utilized other carbohydrates, including xylose, maltose, xylan, starch, and pectin. The main organic fermentation products were propionate, acetate, and succinate. Oxygen, which was not used as electron acceptor, impaired growth. A representative isolate, strain Z-7010, with Marinilabilia salmonicolor as the closest relative, is described as a new genus and species, Alkaliflexus imshenetskii. This is the first cultivated alkaliphilic anaerobic member of the Cytophaga/Flavobacterium/Bacteroides phylum.Dedicated to Prof. Dr. Hans Günter Schlegel on the occasion of his 80th birthday.     

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.     

Desulfosporomusa polytropa gen. nov., sp. nov., a novel sulfate-reducing bacterium from sediments of an oligotrophic lake

Five strains of sulfate-reducing bacteria were isolated from the highest positive dilutions of a most probable number (MPN) series supplemented with lactate and inoculated with sediments from the oligotrophic Lake Stechlin. The isolates were endospore-forming and were motile by means of laterally inserted flagella. They stained Gram-negative and contained b-type cytochromes. CO difference spectra indicated the presence of P582 as a sulfite reductase. Phylogenetic analyses of the 16S rDNA sequences revealed that the isolates were very closely affiliated with the genus Sporomusa. However, sulfate and amorphous Fe(OH)₃, but not sulfite, elemental sulfur, MnO₂, or nitrate were used as terminal electron acceptors. Homoacetogenic growth was found with H₂/CO₂ gas mixture, formate, methanol, ethanol, and methoxylated aromatic compounds. The strains grew autotrophically with H₂ plus CO₂ in the presence or absence of sulfate. Formate, butyrate, several alcohols, organic acids, carbohydrates, some amino acids, choline, and betaine were also utilized as substrates. The growth yield with lactate and sulfate as substrate was 7.0 g dry mass/mol lactate and thus two times higher than in sulfate-free fermenting cultures. All isolates were able to grow in a temperature range of 4–37°C. Physiologically and by the presence of a Gram-negative cell wall, the new isolates resemble known Desulfosporosinus species. However, phylogenetically they are affiliated with the Gram-negative genus Sporomusa belonging to the Selenomonas subgroup of the Firmicutes. Therefore, the new isolates reveal a new phylogenetic lineage of sulfate-reducing bacteria. A new genus and species, Desulfosporomusa polytropa gen. nov., sp. nov. is proposed.Dedicated to Prof. H. G. Schlegel on the occasion of his 80th birthday.     

Anoxybacillus kamchatkensis sp. nov., a novel thermophilic facultative aerobic bacterium with a broad pH optimum from the Geyser valley, Kamchatka

A facultative aerobic, moderately thermophilic, spore forming bacterium, strain JW/VK-KG4 was isolated from an enrichment culture obtained from the Geyser valley, a geothermally heated environment located in the Kamchatka peninsula (Far East region of Russia). The cells were rod shaped, motile, peritrichous flagellated stained Gram positive and had a Gram positive type cell wall. Aerobically, the strain utilized a range of carbohydrates including glucose, fructose, trehalose, proteinuous substrates, and pectin as well. Anaerobically, only carbohydrates are utilized. When growing on carbohydrates, the strain required yeast extract and vitamin B₁₂. Anaerobically, glucose was fermented to lactate as main product and acetate, formate, ethanol as minor products. Aerobically, even in well-aerated cultures (agitated at 500 rpm), glucose oxidation was incomplete and lactate and acetate were found in culture supernatants as by-products. Optimal growth of the isolate was observed at pH^{25 C} 6.8–8.5 and 60°C. The doubling times on glucose at optimal growth conditions were 34 min (aerobically) and 40 min (anaerobically). The G+C content was 42.3 mol% as determined by T_m assay. Sequence analysis of the 16S rRNA gene indicated an affiliation of strain JW/VK-KG4 with Anoxybacillus species. Based on its morphology, physiology, phylogenetic relationship and its low DNA-DNA homology with validly published species of Anoxybacillus, it is proposed that strain JW/VK-KG4 represents a new species in the genus Anoxybacillus as A. kamchatkensis sp. nov. The type strain for the novel species is JW/VK-KG4^T (=DSM 14988, =ATCC BAA-549). The GenBank accession number for the 16S rDNA sequence is AF510985.     

Caldimonas taiwanensis sp. nov., a amylase producing bacterium isolated from a hot spring

During screening for amylase-producing bacteria, a strain designated OnlT was isolated from a hot spring located in Pingtung area, which is near the very southern part of Taiwan. Cells of this organism were Gram-negative rods motile by means of a single polar flagellum. Optimum conditions for growth were 55 degrees C and pH 7. Strain On1(T) grew well in minimal medium containing starch as the sole carbon source, and its extracellular products expressed amylase activity. The 16S rRNA gene sequence analysis indicates that strain On1(T) is a member of beta-Proteobacteria. On the basis of a phylogenetic analysis of 16S rDNA sequences, DNA-DNA similarity data, physiological and biochemical characteristics, as well as fatty acid compositions, the organism belonged to the genus Caldimonas and represented a novel species within this genus. The predominant cellular fatty acids of strain On1(T) were 16:0 (about 30%), 18:1 omega 7c (about 20%) and summed feature 3 (16:1 omega 7c or 15:0 iso 2OH or both [about 31%]). Its DNA base ratio was 65.9 mol% G + C. We propose to classify strain On1(T) (= BCRC 17405T = LMG 22827T) as Caldimonas taiwanensis sp. nov.     

Periplasmic electron carriers and photo-induced electron transfer in the photosynthetic bacterium Ectothiorhodospira sp.

A detailed analysis of the periplasmic electron carriers of the photosynthetic bacterium Ectothiorhodospira sp. has been performed. Two low mid-point redox potential electron carriers, cytochrome c′ and cytochrome c, are detected. A high potential iron–sulfur protein is the only high mid-point redox potential electron transfer component present in the periplasm. Analysis of light-induced absorption changes shows that this high potential iron–sulfur protein acts in vivo as efficient electron donor to the photo-oxidized high potential heme of the Ectothiorhodospira sp. reaction center. This revised version was published online in June 2006 with corrections to the Cover Date.