RESULTS:
1 - 20 of 32 for ""anaerobe""
Properties of the major non-specific endonuclease from the strict anaerobe Fibrobacter succinogenes and evidence for disulfide bond formation in vivo
DNase A is a non-specific endonuclease of Fibrobacter succinogenes. The enzyme was purified to homogeneity and its properties studied both in vitro and in vivo. Magnesium but not calcium was essential for nucleolytic activity. Manganese ions substituted for magnesium but were less stimulatory. DNase A activity was markedly inhibited by either NaCl or KCl at concentrations greater than 75 mM. The enzyme had a temperature optimum of 25 °C and a pH optimum of about 7·0. Values for K m and K cat were determined to be 61 μM and 330 s−1 respectively with a catalytic efficiency approximately threefold greater than bovine pancreatic DNase I but 10-fold less than the Serratia marcescens NucA. DNase A was localized to the periplasm and probably exists as a monomeric species. The enzyme possessed one or more disulfide bonds. In the reduced form it had an apparent mass of 33 kDa while in the oxidized form it was 29 kDa as estimated by SDS-PAGE. Reduction of the disulfide bonds by dithiothreitol with or without subsequent alkylation by iodoacetamide strongly inactivated the enzyme. DNase A accumulated in vivo had an apparent mass of 29 kDa indicating that it was in an oxidized form. This is the first indication in a strict anaerobe of a functional periplasmic disulfide bond forming system phenotypically similar to Dsb systems in facultative and aerobic bacteria.
Thermodesulfobium acidiphilum sp. nov., a thermoacidophilic, sulfate-reducing, chemoautotrophic bacterium from a thermal site
An obligately anaerobic sulfate-reducing micro-organism strain 3127-1T was isolated from geothermally heated soil (Oil Site Uzon Caldera Kamchatka Russia). The new isolate was a moderately thermoacidophilic anaerobe able to grow with H2 or formate by respiration of sulfate or thiosulfate. The pH range for growth was 3.7–6.5 with an optimum at 4.8–5.0. The temperature range for growth was 37–65 °C with an optimum at 55 °C. The G+C content of the genomic DNA was 33.7 mol%. The genome of strain 3127-1T contained two almost identical 16S rRNA genes differing by a single nucleotide substitution. The closest 16S rRNA gene sequence of a validly published species belonged to Thermodesulfobium narugense Na82T (99.5 % similarity). However the average nucleotide identity of the genomes of strain 3127-1T and T. narugense Na82T and the predicted DNA–DNA hybridization value (GGDC 2.1 blast+ formula 2) were as low as 86 and 32.5±2.5 % respectively. This together with phenotypic data showed the new isolate to belong to a novel species for which the name Thermodesulfobium acidiphilum sp. nov. is proposed. The type strain is 3127-1T (=DSM 102892T=VKM B-3043T).
Desulfothermobacter acidiphilus gen. nov., sp. nov., a thermoacidophilic sulfate-reducing bacterium isolated from a terrestrial hot spring
An anaerobic sulfate-reducing micro-organism strain 3408-1T was isolated from a terrestrial hot spring in Kamchatka peninsula (Russia). The cells were spore-forming rods with a Gram-positive type of cell wall. The new isolate was a moderately thermoacidophilic anaerobe able to grow either by sulfate or thiosulfate respiration with H2 or formate as substrates or by fermenting yeast extract maltose sucrose glucose and pyruvate. The fermentation products were acetate CO2 and H2. The pH range for growth was 2.9–6.5 with an optimum at 4.5. The temperature range for growth was 42–70 °C with an optimum at 55 °C. The G+C content of DNA was 58 mol%. Phylogenetic analysis of the 16S rRNA gene showed that strain 3408-1T belongs to the family Thermoanaerobacteraceae order Thermoanaerobacterales and was distantly related to the species of the genus Ammonifex (93–94 % sequence similarity). On the basis of physiological properties and results of phylogenetic analysis strain 3408-1T is considered to represent a novel species of a new genus for which the name Desulfothermobacter acidiphilus gen. nov. sp. nov. is proposed. The type strain is 3408-1T (=DSM 105356T=VKM B-3183T).
Lactobacillus metriopterae sp. nov., a novel lactic acid bacterium isolated from the gut of grasshopper Metrioptera engelhardti
A strain (Hime 5-1T) of lactic acid bacterium was isolated from the gut of the grasshopper Metrioptera engelhardti from a mountainous area of Nagano Prefecture Japan. Strain Hime 5-1T had a low 16S rRNA gene sequence similarity to known lactic acid bacteria with the closest recognized relatives being Lactobacillus tucceti (96.7 %) Lactobacillus furfuricola (96.5 %) Lactobacillus versmoldensis (96.3 %) and Lactobacillus nodensis (96.1 %). Comparative analyses of the rpoA and pheS gene sequences indicated that Hime 5-1T is not closely related to other Lactobacillus species. Strain Hime 5-1T is a Gram-stain-positive catalase-negative and homofermentative bacterium with yellowish colonies which contrasts with the whitish colonies of its closest recognized relatives. Based on phenotypic and genotypic properties we conclude that the isolated bacterium represents a novel species of the genus Lactobacillus for which the name Lactobacillus metriopterae sp. nov. is proposed. The type strain is Hime 5-1T (=JCM 31635T=DSM 103730T). 16S rRNA gene based high-throughput sequencing revealed that L. metriopterae is the dominant microbiota in the gut of Metrioptera engelhardti.
Evidence of persistence of Prevotella spp. in the cystic fibrosis lung
Purpose. Prevotella spp. represent a diverse genus of bacteria frequently identified by both culture and molecular methods in the lungs of patients with chronic respiratory infection. However their role in the pathogenesis of chronic lung infection is unclear; therefore a more complete understanding of their molecular epidemiology is required.
Methodology. Pulsed Field Gel Electrophoresis (PFGE) and Random Amplified Polymorphic DNA (RAPD) assays were developed and used to determine the degree of similarity between sequential isolates (n=42) from cystic fibrosis (CF) patients during periods of clinical stability and exacerbation.
Results. A wide diversity of PFGE and RAPD banding patterns were observed demonstrating considerable within-genus heterogeneity. In 8/12 (66.7 %) cases where the same species was identified at sequential time points pre- and post-antibiotic treatment of an exacerbation PFGE/RAPD profiles were highly similar or identical. Congruence was observed between PFGE and RAPD (adjusted Rand coefficient 0.200; adjusted Wallace RAPD->PFGE 0.459 PFGE->RAPD 0.128). Furthermore some isolates could not be adequately assigned a species name on the basis of 16S rRNA analysis: these isolates had identical PFGE/RAPD profiles to Prevotella histicola.
Conclusion. The similarity in PFGE and RAPD banding patterns observed in sequential CF Prevotella isolates may be indicative of the persistence of this genus in the CF lung. Further work is required to determine the clinical significance of this finding and to more accurately distinguish differences in pathogenicity between species.
Prevotella colorans sp. nov., isolated from a human wound
A strain of obligately anaerobic Gram-stain-negative and non-spore-forming rod-shaped bacterium was isolated from a human wound and characterized both phenotypically and genotypically. The strain was moderately saccharolytic and proteolytic. Phylogenetic analysis was based on full-length 16S rRNA gene sequence analysis and revealed the strain to represent a member of the genus Prevotella but to be different from the described species with the closest relationship to Prevotella bergensis and Prevotella multisaccharivorax. The genomic DNA G+C content was 43.2 mol%. The most abundant cellular long-chain fatty acids were 3-OH iso-C17 : 0 anteiso-C15 : 0 and iso-C15 : 0. In view of phenotypical and biochemical characteristics as well as gene sequencing strain A1336T is considered to represent a novel species within the genus Prevotella for which the name Prevotella colorans sp. nov. is proposed. The type strain is A1336T (=DSM 100333T =CCUG 67421T =CCOS 902T).
Description of two novel members of the family Erysipelotrichaceae: Ileibacterium valens gen. nov., sp. nov. and Dubosiella newyorkensis, gen. nov., sp. nov., from the murine intestine, and emendation to the description of Faecalibacterium rodentium
To better characterize murine intestinal microbiota a large number (187) of Gram-positive-staining rod- and coccoid-shaped and facultatively or strictly anaerobic bacteria were isolated from small and large intestinal contents from mice. Based on 16S rRNA gene sequencing a total 115 isolates formed three phylogenetically distinct clusters located within the family Erysipelotrichaceae . Group 1 as represented by strain NYU-BL-A3T was most closely related to Allobaculum stercoricanis with 16S rRNA gene sequence similarity values of 87.7 %. A second group represented by NYU-BL-A4T was most closely related to Faecalibaculum rodentium with 86.6 % 16S rRNA gene sequence similarity. A third group had a nearly identical 16S rRNA gene sequence (99.9 %) compared with the recently described Faecalibaculum rodentium also recovered from a laboratory mouse; however this strain had a few differences in biochemical characteristics which are detailed in an emended description. The predominant (>10 %) cellular fatty acids of strain NYU-BL-A3T were C16 : 0 and C18 : 0 and those of strain NYU-BL-A4T were C10 : 0 C16 : 0 C18 : 0 and C18 : 1ω9c. The two groups could also be distinguished by multiple biochemical reactions with the group represented by NYU-BL-A4T being considerably more active. Based on phylogenetic biochemical and chemotaxonomic criteria two novel genera are proposed Ileibacterium valens gen. nov. sp. nov. with NYU-BL-A3T (=ATCC TSD-63T=DSM 103668T) as the type strain and Dubosiella newyorkensis gen. nov. sp. nov. with NYU-BL-A4T (=ATCC TSD-64T=DSM 103457T) as the type strain.
Harryflintia acetispora gen. nov., sp. nov., isolated from chicken caecum
More than 100 isolates of a Gram-stain-negative curved rod-shaped so far uncultured bacterium were isolated from chicken caecal content. The strains were obligate anaerobes which formed endospores. They were catalase-positive cytochrome-oxidase-negative and did not hydrolyse aesculin. The detected predominant metabolic end product in reinforced clostridial bedium broth was acetate. The DNA G+C content was 62.2 mol%. The cell fatty acid composition was dominated by C15 : 0 iso C15 : 0 anteiso C16 : 0 C13 : 0 iso C14 : 0 iso and C16 : 0 DMA. Analysis of the 16S rRNA gene sequences of the novel isolates showed 99 % similarity to each other. Phylogenetically they are placed in Clostridium cluster IV. They exhibited 99 % 16S rRNA gene sequence similarity to uncultured bacterial clone SJTU_C_03_83 (GenBank accession no. EF404038.1) and to three other so far uncultured strains. The closest related type strains Hydrogenoanaerobacterium saccharovorans SW51T and Anaerotruncus colihominis WAL 14565T exhibited a 16S rRNA gene sequence divergence of at least 8 % to the newly described isolates. In addition morphological and biochemical characteristics allowed differentiation of the novel isolates from these and other related and validly published species including Clostridium methylpentosum and Acetanaerobacterium elongatum . Therefore a new genus Harryflintia gen. nov. is proposed for the isolated hitherto unknown strains with V20-281aT (=DSM 100433T =CECT 8892T) as the type strain of its type species Harryflintia acetispora gen. nov. sp. nov.
Cloning, sequencing and expression of an α-amylase gene, amyA, from the thermophilic halophile Halothermothrix orenii and purification and biochemical characterization of the recombinant enzyme a aThe GenBank accession number for the sequence reported in this paper is AF442961.
aThe GenBank accession number for the sequence reported in this paper is AF442961.
A recombinant clone expressing an amylase was identified from an Escherichia coli generated genomic library of the thermophilic moderately halophilic anaerobic bacterium Halothermothrix orenii by activity screening and the gene encoding the enzyme was designated AmyA. The amyA gene was 1545 bp long and encoded a 515 residue protein composed of a 25 amino acid putative signal peptide and a 490 amino acid mature protein. It possessed the five consensus regions characteristic of the α-amylase family and showed the greatest homology to the Bacillus megaterium group of α-amylases. The amyA gene was expressed in E. coli as a hexahistidine-tagged enzyme and purified. The purified recombinant enzyme was optimally active at 65 °C in 5% (w/v) NaCl at pH 7·5 with significant activity retained in the presence of up to 25% (w/v) NaCl. It had a specific activity of 22·32 U mg−1 and required NaCl and CaCl2 for optimum activity and thermostability. The relatively high proportion of acidic amino acids typically observed for many enzymes from halophiles was absent in H. orenii AmyA.
Raineyella antarctica gen. nov., sp. nov., a psychrotolerant, d-amino-acid-utilizing anaerobe isolated from two geographic locations of the Southern Hemisphere
A Gram-stain-positive bacterium strain LZ-22T was isolated from a rhizosphere of moss Leptobryum sp. collected at the shore of Lake Zub in Antarctica. Cells were motile straight or pleomorphic rods with sizes of 0.6–1.0×3.5–10 µm. The novel isolate was a facultatively anaerobic catalase-positive psychrotolerant mesophile. Growth was observed at 3–41 °C (optimum 24–28 °C) with 0–7 % (w/v) NaCl (optimum 0.25 %) and at pH 4.0–9.0 (optimum pH 7.8). The quinone system of strain LZ-22T possessed predominately menaquinone MK-9(H4). The genomic G+C content was 70.2 mol%. Strain 10J was isolated from a biofilm of sediment microbial fuel cell in Uruguay and had 99 % 16S rRNA gene sequence similarity to strain LZ-22T. DNA–DNA-hybridization values of 84 % confirmed that both strains belonged to the same species. Both strains grew on sugars proteinaceous compounds and some amino- and organic acids. Strain LZ-22T uniquely grew on D-enantiomers of histidine and valine while neglecting growth on L-enantiomers. Both strains were sensitive to most of the tested antibiotics but resistant to tested nitrofurans and sulfanilamides. Phylogenetic analyses of the 16S rRNA gene sequences indicated that the strains were related to members of the family Propionibacteriaceae (~93–94 % 16S rRNA gene sequence similarity) with formation of a separate branch within the radiation of the genera Granulicoccus and Luteococcus . Based on phenotypic and genotypic characteristics we propose the affiliation of both strains into a novel species of a new genus. The name Raineyella antarctica gen. nov. sp. nov. is proposed for the novel taxon with the type strain LZ-22T (=ATCC TSD-18T=DSM 100494T=JCM 30886T).
Caecibacterium sporoformans gen. nov., sp. nov., an anaerobic, butyrate-producing, spore-forming bacterium isolated from chicken caecum
Strains of a Gram-stain-negative rod-shaped and immotile bacterium were isolated from broiler chicken caecal content. The isolates required strict anaerobic conditions for growth formed spores were catalase-positive and oxidase-negative. They produced butyrate as the major metabolic end product in reinforced clostridial medium broth. The genomic DNA G+C content of the isolated strains was 32.5–34.6 mol%. The major cellular fatty acids were C16 : 0 FAME C14 : 0 FAME C19 : 0CYC 910DMA and C16 : 0DMA. The fatty acid composition of the cell wall showed no similarity to any strain in the midi database. 16S rRNA gene sequence analysis showed that the nearest phylogenetic neighbours were Anaerostipes hadrus and Clostridium populeti (92 % sequence similarity) within Clostridium cluster XIVa of the phylum Firmicutes . Therefore a novel genus is proposed with the name Caecibacterium sporoformans gen. nov. sp. nov. The type strain of Caecibacterium sporoformans is LMG 27730T=DSM 26959T.
Dissulfurirhabdus thermomarina gen. nov., sp. nov., a thermophilic, autotrophic, sulfite-reducing and disproportionating deltaproteobacterium isolated from a shallow-sea hydrothermal vent
A thermophilic anaerobic chemolithoautotrophic bacterium strain SH388T was isolated from a shallow submarine hydrothermal vent (Kuril Islands Russia). Cells of strain SH388T were Gram-stain-negative short rods 0.2–0.4 µm in diameter and 1.0–2.5 µm in length and motile with flagella. The temperature range for growth was 25–58 °C (optimum 50 °C) and the pH range for growth was pH 5.0–7.0 (optimum pH 6.0–6.5). Growth of strain SH388T was observed in the presence of NaCl concentrations ranging from 0.5 to 4.0 % (w/v) (optimum 2.0–2.5 %). The strain grew chemolithoautotrophically with molecular hydrogen as electron donor sodium sulfite as electron acceptor and bicarbonate/CO2 as a carbon source. It was also able to grow by disproportionation of sulfite and elemental sulfur but not thiosulfate. Sulfate Fe(III) and nitrate were not used as electron acceptors either with H2 or organic electron donors. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the class Deltaproteobacteria and was most closely related to Dissulfuribacter thermophilus and Dissulfurimicrobium hydrothermale (91.6 % and 90.4 % sequence similarity). On the basis of its physiological properties and results of phylogenetic analyses strain SH388T is considered to represent a novel species of a new genus for which the name Dissulfurirhabdus thermomarina gen. nov. sp. nov. is proposed. The type strain of the species is SH388T (=DSM 100025T=VKM B-2960T). It is the first thermophilic disproportionator of sulfur compounds isolated from a shallow-sea environment.
Thermodesulfitimonas autotrophica gen. nov., sp. nov., a thermophilic, obligate sulfite-reducing bacterium isolated from a terrestrial hot spring
A novel thermophilic anaerobic chemolithoautotrophic bacterium strain SF97T was isolated from a terrestrial hot spring (Kuril Islands Russia). Cells of strain SF97T were rod-shaped and motile with a Gram-positive cell-wall type. The novel isolate grew at 45–72 °C (optimum 65 °C) and pH 5.5–8.5 (optimum 6.0–6.5). The strain grew chemolithoautotrophically with molecular hydrogen as an electron donor sodium sulfite or SO2 gas as an electron acceptor and bicarbonate/CO2 as a carbon source. Sulfate thiosulfate elemental sulfur Fe(III) or nitrate were not used as electron acceptors either with H2 or organic electron donors. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the family Thermoanaerobacteraceae order Thermoanaerobacterales and was distantly related to species of the genus Ammonifex (92–93 % sequence similarity). On the basis of its physiological properties and results of phylogenetic analyses strain SF97T is considered to represent a novel species of a new genus for which the name Thermodesulfitimonas autotrophica gen. nov. sp. nov. is proposed. The type strain of Thermodesulfitimonas autotrophica is SF97T (=DSM 102936T=VKM B-2961T). T. autotrophica is the first reported obligate sulfite-reducing micro-organism.
Lentimicrobium saccharophilum gen. nov., sp. nov., a strictly anaerobic bacterium representing a new family in the phylum Bacteroidetes, and proposal of Lentimicrobiaceae fam. nov.
A novel strictly anaerobic short rod-shaped bacterium designated strain TBC1T was isolated from methanogenic granular sludge in a full-scale mesophilic upflow anaerobic sludge blanket reactor treating high-strength starch-based organic wastewater. Cells of this strain were 2–4 µm long and 0.4–0.6 µm wide. They were non-motile and Gram-stain-negative. The optimum growth temperature was 30–37 °C with a range of 20–40 °C. The optimum pH for growth was around pH 7.0 while growth occurred in a range of pH 6.5–9.0. Strain TBC1T grew chemo-organotrophically on a narrow range of carbohydrates under anaerobic conditions. Yeast extract was required for its growth. The major fermentative end products from glucose supplemented with yeast extract were acetate malate propionate formate and hydrogen. Doubling time under optimal growth conditions was estimated to be 1 day. The DNA G+C content of strain TBC1T was 49.2 mol% as determined by HPLC. Major cellular fatty acids were C16 : 0 C18 : 0 C16 : 1 ω9c and C18 : 1 ω9c. Based on its 16S rRNA gene sequence strain TBC1T was shown to represent a distinct lineage at the family level in the phylum Bacteroidetes . Among previously described species of this phylum Mucilaginibacter boryungensis BDR-9T ( Sphingobacteriaceae ) displayed the highest sequence similarity (85.9 %) with strain TBC1T. Phylogenomic analyses using 38–83 single copy marker genes also supported the novelty of strain TBC1T at the family level. Based on its characteristics strain TBC1T (=JCM 30898T=DSM 100618T) is considered to be the type strain of a novel species of a new genus Lentimicrobium saccharophilum gen. nov. sp. nov. A new family Lentimicrobiaceae fam. nov. is also proposed encompassing the strain and related environmental 16S rRNA gene clone sequences.
Clostridium beihaiense sp. nov., an anaerobic bacterium isolated from activated sludge
A Gram-positive strictly anaerobic rod-shaped bacterium designated YB-7T was isolated from activated sludge of an anaerobic baffled reactor pond in Weizhou terminal wastewater treatment plant Beihai Guangxi China. Strain YB-7T grew at pH 5.0–12.0 (optimum pH 7.0) 20–45 °C (37 °C) and NaCl concentration of 0–5 % w/v (optimum 5 %). 16S rRNA gene sequence analysis results showed that strain YB-7T belonged to the genus Clostridium and it was most closely related to Clostridium tetanomorphum DSM 4474T (96.9 % similarity). The DNA–DNA relatedness of strain YB-7T to Clostridium tetanomorphum DSM 4474T was 47.4 %. The DNA G+C content of strain YB-7T was determined to be 32.3 mol% and the predominant cellar fatty acid (>10 %) was C16 : 0. Polar lipids of strain YB-7T included diphosphatidylglycerol phosphatidylethylethanolamine phosphatidylethanolamine phosphatidylglycerol phosphatidylcholine two unidentified aminophospholipids two unidentified phospholipids and unidentified lipids. The results of this study supported the conclusion that strain YB-7T should be assigned to a new member of the genus Clostridium for which the name Clostridium beihaiense sp. nov. is proposed. The type strain is YB-7T (=CICC 24109T=KCTC 15555T).
Calorimonas adulescens gen. nov., sp. nov., an anaerobic thermophilic bacterium utilizing methoxylated benzoates
A novel anaerobic thermophilic bacterium (strain A05 MBT) was isolated from Daginsky thermal springs (Sakhalin Russia) on 2-methoxybenzoate as a substrate. Cells of the strain were motile long rods 3.0–5.0 µm in length and 0.5–0.6 µm in diameter. The temperature range for growth was 47–68 °C with an optimum at 60 °C. The pH range for growth was 4.5–8.0 with an optimum at pH 5.5–6.0. Strain A05 MBT did not require NaCl for growth. The strain utilized methoxylated aromatic compounds (2-methoxybenzoate and 34-dimethoxybenzoate) a number of carbohydrates (glucose fructose mannose trehalose xylose sucrose galactose ribose maltose raffinose lactose cellobiose and dextrin) and proteinaceous substrates (yeast extract beef extract peptone and tryptone). The end products of glucose fermentation were acetate ethanol and CO2. The DNA G+C content of strain A05 MBT was 40.2 mol% (whole-genome analysis). 16S rRNA gene sequence analysis revealed that strain A05MBT belongs to the order Thermoanaerobacterales (phylum Firmicutes ). The closest relative of strain A05 MBT was Caloribacterium cisternae (94.3 % 16S rRNA gene sequence similarity). Based on the phenotypic genotypic and phylogenetic characteristics of the isolate strain A05 MBT is considered to represent a novel species of a new genus for which the name Calorimonas adulescens gen. nov. sp. nov. is proposed. The type strain of Calorimonas adulescens is A05 MBT (=KCTC 15839T=VKM B-3388T).
Mariniplasma anaerobium gen. nov., sp. nov., a novel anaerobic marine mollicute, and proposal of three novel genera to reclassify members of Acholeplasma clusters II–IV
A novel strictly anaerobic chemoorganotrophic bacterium designated Mahy22T was isolated from sulfidic bottom water of a shallow brackish meromictic lake in Japan. Cells of the strain were Gram-stain-negative non-motile and coccoid in shape with diameters of about 600–800 nm. The temperature range for growth was 15–37 °C with optimum growth at 30–32 °C. The pH range for growth was pH 6.2–8.9 with optimum growth at pH 7.2–7.4. The strain grew with NaCl concentrations of 5% or below (optimum 2–3%). Growth of the strain was enhanced by the addition of thiosulfate. The major cellular fatty acids were C16:0 and anteiso-C15:0. Respiratory quinones were not detected. The complete genome sequence of strain Mahy22T possessed a 1 885 846 bp circular chromosome and a 12 782 bp circular genetic element. The G+C content of the genome sequence was 30.1 mol%. Phylogenetic analysis based on the 16S rRNA gene revealed that the novel strain belonged to the family Acholeplasmataceae class Mollicutes . The closest relative of strain Mahy22T with a validly published name was Acholeplasma palmae J233T with a 16S rRNA gene sequence similarity of 90.5%. Based on the results of polyphasic analysis the name Mariniplasma anaerobium gen. nov. sp. nov. is proposed to accommodate strain Mahy22T along with reclassification of some Acholeplasma species into Alteracholeplasma gen. nov. Haploplasma gen. nov. and Paracholeplasma gen. nov.
Redescription and SSU rRNA gene-based phylogeny of an anaerobic ciliate, Plagiopyla ovata Kahl, 1931 (Ciliophora, Plagiopylea)
The morphology and molecular phylogeny of Plagiopyla ovata Kahl 1931 a poorly known anaerobic ciliate were investigated based on a population isolated from sand samples collected from the Yellow Sea coast at Qingdao PR China. Details of the oral ciliature are documented for the first time to our knowledge and an improved species diagnosis is given. The small subunit ribosomal RNA (SSU rRNA) gene was newly sequenced and phylogenetic analyses revealed that P. ovata clusters within the monophyletic family Plagiopylidae. However evolutionary relationships within both the family Plagiopylidae and the genus Plagiopyla remain obscure owing to undersampling the lack of sequence data from known species and low nodal support or unstable topologies in gene trees. A key to the identification of the species of the genus Plagiopyla with validly published names is also supplied.
Multiple lactate dehydrogenase activities of the rumen bacterium Selenomonas ruminantium
The lactate utilizing strain of Selenomonas ruminantium 5934e was found to contain three lactate dehydrogenase (LDH) activities in sonicated cell extracts. One activity an NAD dependent L-LDH (L-nLDH) was measured at 15-fold greater levels in extracts of cells grown to mid-exponential phase on glucose compared to cells grown to the equivalent growth stage on DL-lactate. A second nLDH activity specific for D-lactate (D-nLDH) was detected at similar levels in both lactate-grown cell extracts and glucose-grown cell extracts. The third activity an NAD independent DLDH (D-iLDH) was very low in cells grown on glucose but was induced more than 10-fold when DL-lactate was used as the carbon source. The three LDH activities could be separated by gel filtration. Recovery of the activities was low due to the apparent instability of the enzymes at 4 °C which was most pronounced in the case of the D-iLDH. A Km for lactate of 0.5 mM was estimated for the D-iLDH and this was considerably lower than the values of 45 mM and 70 mM measured for L-nLDH and D-nLDH respectively. It is proposed that the D-iLDH may be largely responsible for the formation of pyruvate in lactate-grown cells of S. ruminantium strain 5934e. Three other lactate utilizing strains of S. ruminantium HD4 5521C1 and JW13 exhibited a similar profile of LDH activities to strain 5934e when grown on glucose and DL-lactate.
Haloanaerobium kushneri sp. nov., an obligately halophilic, anaerobic bacterium from an oil brine
Three strains designated VS-751T VS-511 and VS-732 of a strictly anaerobic moderately halophilic Gram-negative rod-shaped bacterium were isolated from a highly saline (15-20%) brine from an oil reservoir in central Oklahoma USA. The optimal concentration of NaCI for growth of these three strains was 2 M (12%) and the strains also grew in the presence of an additional 1 M MgCl2. The strains were mesophilic and grew at a pH range of 6–8. Carbohydrates used by all three strains included glucose fructose arabinose galactose maltose mannose cellobiose sucrose and inulin. Glucose fermentation products included ethanol acetate H2 and CO2 with formate produced by two of the three strains. Differences were noted among strains in the optimal temperature and pH for growth the maximum and minimum NaCl concentration that supported growth substrate utilization and cellular fatty acid composition. Despite the phenotypic differences among the three strains analysis of the 16S rRNA gene sequences and DNA-DNA hybridizations showed that these three strains were members of the same genospecies which belonged to the genus Haloanaerobium. The phenotypic and genotypic characteristics of strains VS-751T VS-511 and VS-732 are different from those of previously described species of Haloanaerobium. It is proposed that strain VS-751T (ATCC 7001031T) be established as the type strain of a new species Haloanaerobium kushneri.