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Volume 52,
Issue 2,
2002
Volume 52, Issue 2, 2002
- Articles
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The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa.
More LessEukaryotes and archaebacteria form the clade neomura and are sisters, as shown decisively by genes fragmented only in archaebacteria and by many sequence trees. This sisterhood refutes all theories that eukaryotes originated by merging an archaebacterium and an alpha-proteobacterium, which also fail to account for numerous features shared specifically by eukaryotes and actinobacteria. I revise the phagotrophy theory of eukaryote origins by arguing that the essentially autogenous origins of most eukaryotic cell properties (phagotrophy, endomembrane system including peroxisomes, cytoskeleton, nucleus, mitosis and sex) partially overlapped and were synergistic with the symbiogenetic origin of mitochondria from an alpha-proteobacterium. These radical innovations occurred in a derivative of the neomuran common ancestor, which itself had evolved immediately prior to the divergence of eukaryotes and archaebacteria by drastic alterations to its eubacterial ancestor, an actinobacterial posibacterium able to make sterols, by replacing murein peptidoglycan by N-linked glycoproteins and a multitude of other shared neomuran novelties. The conversion of the rigid neomuran wall into a flexible surface coat and the associated origin of phagotrophy were instrumental in the evolution of the endomembrane system, cytoskeleton, nuclear organization and division and sexual life-cycles. Cilia evolved not by symbiogenesis but by autogenous specialization of the cytoskeleton. I argue that the ancestral eukaryote was uniciliate with a single centriole (unikont) and a simple centrosomal cone of microtubules, as in the aerobic amoebozoan zooflagellate Phalansterium. I infer the root of the eukaryote tree at the divergence between opisthokonts (animals, Choanozoa, fungi) with a single posterior cilium and all other eukaryotes, designated 'anterokonts' because of the ancestral presence of an anterior cilium. Anterokonts comprise the Amoebozoa, which may be ancestrally unikont, and a vast ancestrally biciliate clade, named 'bikonts'. The apparently conflicting rRNA and protein trees can be reconciled with each other and this ultrastructural interpretation if long-branch distortions, some mechanistically explicable, are allowed for. Bikonts comprise two groups: corticoflagellates, with a younger anterior cilium, no centrosomal cone and ancestrally a semi-rigid cell cortex with a microtubular band on either side of the posterior mature centriole; and Rhizaria [a new infrakingdom comprising Cercozoa (now including Ascetosporea classis nov.), Retaria phylum nov., Heliozoa and Apusozoa phylum nov.], having a centrosomal cone or radiating microtubules and two microtubular roots and a soft surface, frequently with reticulopodia. Corticoflagellates comprise photokaryotes (Plantae and chromalveolates, both ancestrally with cortical alveoli) and Excavata (a new protozoan infrakingdom comprising Loukozoa, Discicristata and Archezoa, ancestrally with three microtubular roots). All basal eukaryotic radiations were of mitochondrial aerobes; hydrogenosomes evolved polyphyletically from mitochondria long afterwards, the persistence of their double envelope long after their genomes disappeared being a striking instance of membrane heredity. I discuss the relationship between the 13 protozoan phyla recognized here and revise higher protozoan classification by updating as subkingdoms Lankester's 1878 division of Protozoa into Corticata (Excavata, Alveolata; with prominent cortical microtubules and ancestrally localized cytostome--the Parabasalia probably secondarily internalized the cytoskeleton) and Gymnomyxa [infrakingdoms Sarcomastigota (Choanozoa, Amoebozoa) and Rhizaria; both ancestrally with a non-cortical cytoskeleton of radiating singlet microtubules and a relatively soft cell surface with diffused feeding]. As the eukaryote root almost certainly lies within Gymnomyxa, probably among the Sarcomastigota, Corticata are derived. Following the single symbiogenetic origin of chloroplasts in a corticoflagellate host with cortical alveoli, this ancestral plant radiated rapidly into glaucophytes, green plants and red algae. Secondary symbiogeneses subsequently transferred plastids laterally into different hosts, making yet more complex cell chimaeras--probably only thrice: from a red alga to the corticoflagellate ancestor of chromalveolates (Chromista plus Alveolata), from green algae to a secondarily uniciliate cercozoan to form chlorarachneans and independently to a biciliate excavate to yield photosynthetic euglenoids. Tertiary symbiogenesis involving eukaryotic algal symbionts replaced peridinin-containing plastids in two or three dinoflagellate lineages, but yielded no major novel groups. The origin and well-resolved primary bifurcation of eukaryotes probably occurred in the Cryogenian Period, about 850 million years ago, much more recently than suggested by unwarranted backward extrapolations of molecular 'clocks' or dubious interpretations as 'eukaryotic' of earlier large microbial fossils or still more ancient steranes. The origin of chloroplasts and the symbiogenetic incorporation of a red alga into a corticoflagellate to create chromalveolates may both have occurred in a big bang after the Varangerian snowball Earth melted about 580 million years ago, thereby stimulating the ensuing Cambrian explosion of animals and protists in the form of simultaneous, poorly resolved opisthokont and anterokont radiations.
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Phylogenetic analysis of Xanthomonas species based upon 16S-23S rDNA intergenic spacer sequences.
More LessPhylogenetic relationships of 17 species of Xanthomonas were assessed based on analysis of 16S-23S rDNA intergenic spacer (ITS) sequences; a higher level of resolution was obtained than that revealed by 16S rDNA analysis. ITS sequences varied in size from 492 to 578 nt within the genus and the similarity among sequences ranged from 63 to 99%. Major differences were found for the hyacinthi group, which included Xanthomonas albilineans, Xanthomonas hyacinthi, Xanthomonas sacchari, Xanthomonas theicola and Xanthomonas translucens. A common ITS structure with tRNA(Ala) and tRNA(Ile) embedded within the sequence was found for all ITS sequences of Xanthomonas species and for Stenotrophomonas maltophilia. These tRNAs were highly conserved and divided the ITS sequence into three regions (ITS1, ITS2 and ITS3). ITS1 and ITS2 sequences of Xanthomonas species showed mean similarities of 87.1 and 86.8%, respectively, and differences consisted of substitution and addition/deletion of 1-5 nt. ITS2 showed remarkable variation in sequence length: most species had an ITS2 of 19-20 nt, whereas a long insertion of 51-56 nt was found in Xanthomonas codiaei, X. hyacinthi, Xanthomonas melonis, X. theicola and X. translucens. For ITS3 the most striking alteration was seen in X. hyacinthi, which showed a large deletion of 44 nt. The ITS phylogenetic tree grouped Xanthomonas species into six major clusters. Cluster I included Xanthomonas arboricola, Xanthomonas axonopodis, Xanthomonas bromi, Xanthomonas campestris, X. campestris pv. gardneri, Xanthomonas cassavae, X. codiaei, Xanthomonas cucurbitae, Xanthomonas fragariae, Xanthomonas hortorum, X. melonis, Xanthomonas oryzae, Xanthomonas pisi, Xanthomonas vasicola and Xanthomonas vesicatoria. The species X. albilineans, X. sacchari, X. hyacinthi, X. theicola and X. translucens represented distinct clusters (II-VI). Topology of the 16S-23S rDNA ITS phylogenetic tree was very similar to that of the 16S rDNA tree reported previously, but more clusters were discriminated because of the higher level of diversity among the ITS sequences (16.2%) compared with the 16S rDNA sequences (1.8%).
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Pseudomonas mosselii sp. nov., a novel species isolated from clinical specimens.
Twenty-two fluorescent pseudomonad strains of clinical origin received as Pseudomonas fluorescens (10 strains), Pseudomonasputida (10 strains) and Pseudomonas sp. (2 strains), and 33 type strains of the genus Pseudomonas were studied by numerical analysis based on 280 phenotypic characters. Twelve of the 22 clinical isolates clustered within a specific group, cluster IV. The other strains clustered within groups containing well-characterized fluorescent Pseudomonas species or did not cluster. Strains belonging to cluster IV were phenotypically different from all other clusters and subclusters of fluorescent pseudomonads. DNA-DNA hybridization showed that cluster IV corresponded to a genomic group sharing 72-100% DNA relatedness. DNA-DNA hybridization values with 67 strains representing 30 species of the genus Pseudomonas sensu stricto, including six recently described species (Pseudomonas veronii, Pseudomonas rhodesiae, Pseudomonas libanensis, 'Pseudomonas orientalis', 'Pseudomonas cedrella' and Pseudomonas monteilii), were below 49%, the value found for P. monteilii. The DNA G+C content of the type strain was 63 mol%. Comparison of the 16S rRNA gene sequence of a representative strain of cluster IV (CFML 90-83T) with sequences of other strains of the genus Pseudomonas revealed that strain CFML 90-83T was part of the P. fluorescens intrageneric cluster. On the basis of phenotypic, DNA-DNA hybridization and phylogenetic analyses, a novel species, Pseudomonas mosselii sp. nov., is proposed for the 12 strains of cluster IV. The type strain is P. mosselii CFML 90-83T (= ATCC BAA-99T = CIP 105259T). The P. mosselii strains are phenotypically homogeneous and can be differentiated from other fluorescent species by several phenotypic features, including pyoverdine typing.
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Comamonas koreensis sp. nov., a non-motile species from wetland in Woopo, Korea.
A bacterial strain, designated YH12T, was isolated from a wetland sample collected from Woopo, Republic of Korea, and characterized using a polyphasic approach. Analysis of 16S rDNA indicated that the isolate formed a monophyletic clade with the members of the genus Comamonas. The closest phylogenetic relative among the valid species was Comamonas testosteroni, with 96.6% 16S rDNA similarity. The chemotaxonomic properties of the wetland isolate supported its membership of the genus Comamonas, as it contained ubiquinone Q-8 as a major respiratory quinone and hexadecanoic, methylene-hexadecanoic and octadecenoic acids as major cellular fatty acids. The G+C content of the DNA was 66 mol%. The isolate is a gram-negative, non-pigmented, rod-shaped, oxidase- and catalase-positive, non-motile, non-endospore-forming and non-fermentative bacterium. The phenotypic properties of the isolate were compared with those of the type strains of Comamonas terrigena, C. testosteroni and Delftia acidovorans. A number of tests, including motility, can differentiate our isolate from related taxa. On the basis of the 16S rDNA phylogenetic, chemotaxonomic and phenotypic evidence given in this study, it is proposed that strain YH12T (= KCTC 12005T = IMSNU 11158T) be assigned as the type strain of a novel species of the genus Comamonas, Comamonas koreensis sp. nov.
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Bartonella bovis Bermond et al. sp. nov. and Bartonella capreoli sp. nov., isolated from European ruminants.
Two novel species of Bartonella isolated from European ruminants are described. Bartonella capreoli sp. nov. was isolated from the blood of roe-deer (Capreolus capreolus) captured in Chizé, France. The type strain is IBS 193T (= CIP 106691T = CCUG 43827T). It is distinct from another European ruminant isolate that originated from a cow from a French herd of 430 dairy cattle. The latter isolate belongs to a novel species named Bartonella bovis Bermond et al. sp. nov. The type strain is strain 91-4T (= CIP 106692T = CCUG 43828T). The two bacteria appeared as small, fastidious, aerobic, oxidase-negative, gram-negative rods. Their biochemical properties were similar to those of members of the genus Bartonella. The sequences of the 16S rRNA and citrate synthase genes obtained from the two type strains were highly related to sequences of the different Bartonella species. Hybridization values when testing type strains of recognized Bartonella species, obtained with the nuclease/trichloroacetic acid method, support the creation of two novel species.
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Desulfotomaculum thermobenzoicum subsp. thermosyntrophicum subsp. nov., a thermophilic, syntrophic, propionate-oxidizing, spore-forming bacterium.
More LessFrom granular sludge from a laboratory-scale upflow anaerobic sludge bed reactor operated at 55 degrees C with a mixture of volatile fatty acids as feed, a novel anaerobic, moderately thermophilic, syntrophic, spore-forming bacterium, strain TPO, was enriched on propionate in co-culture with Methanobacterium thermoautotrophicum Z245. The axenic culture was obtained by using pyruvate as the sole source of carbon and energy. The cells were straight rods with pointed ends and became lens-shaped when sporulation started. The cells were slightly motile. The optimum growth temperature was 55 degrees C and growth was possible between 45 and 62 degrees C. The pH range for growth of strain TPO was 6-8, with an optimum at pH 7-7.5. Propionate was converted to acetate, CO2 and CH4 by a co-culture of strain TPO with Methanobacterium thermoautotrophicum Z245. In pure culture, strain TPO could grow fermentatively on benzoate, fumarate, H2/CO2, pyruvate and lactate. Sulphate could serve as inorganic electron acceptor when strain TPO was grown on propionate, lactate, pyruvate and H2/CO2. The G+C content was 53.7 mol%. Comparison of 16S rDNA sequences revealed that strain TPO is related to Desulfotomaculum thermobenzoicum (98%) and Desulfotomaculum thermoacetoxidans (98%). DNA-DNA hybridization revealed 88.2% reassociation between strain TPO and D. thermobenzoicum and 83.8% between strain TPO and D. thermoacetoxidans. However, both organisms differ physiologically from strain TPO and are not capable of syntrophic propionate oxidation. It is proposed that strain TPO should be classified as new subspecies of D. thermobenzoicum as D. thermobenzoicum subsp. thermosyntrophicum.
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Gelria glutamica gen. nov., sp. nov., a thermophilic, obligately syntrophic, glutamate-degrading anaerobe.
More LessA novel anaerobic, gram-positive, thermophilic, spore-forming, obligately syntrophic, glutamate-degrading bacterium, strain TGO(T), was isolated from a propionate-oxidizing methanogenic enrichment culture. The axenic culture was obtained by growing the bacterium on pyruvate. Cells were rod-shaped and non-motile. The optimal temperature for growth was 50-55 degrees C and growth occurred between 37 and 60 degrees C. The pH range for growth was 5.5-8 with optimum growth at pH 7. In pure culture, strain TGO(T) could grow on pyruvate, lactate, glycerol and several sugars. In co-culture with the hydrogenotrophic methanogen Methanobacterium thermautotrophicum strain Z-245, strain TGO(T) could grow on glutamate, proline and Casamino acids. Glutamate was converted to H2, CO2, propionate and traces of succinate. Strain TGO(T) was not able to utilize sulphate, sulphite, thiosulphate, nitrate or fumarate as electron acceptors. The G+C content was 33.8 mol%. Sequence analysis of the 16S rDNA revealed that strain TGO(T) belongs to the thermophilic, endospore-forming anaerobes, though no close relations were found. Its closest relations were Moorella glycerini (92%) and Moorella thermoacetica (90%). Strain TGOT had an unusually long 16S rDNA of more than 1700 bp. The additional base pairs were found as long loops in the V1, V7 and V9 regions of the 16S rDNA. However, the loops were not found in the 16S rRNA. The name Gelria glutamica gen. nov., sp. nov. is proposed for strain TGO(T).
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Rhodococcus jostii sp. nov., isolated from a medieval grave.
More LessThe taxonomic position of a bacterial strain isolated from the femur of the remains of Jost Lucemburský, margrave in Moravia, Brno (Czech Republic), was investigated by phenotypic, chemotaxonomic and molecular taxonomic methods. The chemotaxonomic characteristics, including the cell-wall amino acid and sugar compositions, the quinone system and the fatty acid profile, were in good agreement with those of the genus Rhodococcus. The G+C content of the DNA was 67.4 mol%. Comparative 16S rRNA gene sequencing demonstrated that the unknown strain represents a distinct line of descent within the genus Rhodococcus. The nearest relatives of the bacterium were Rhodococcus opacus and Rhodococcus percolatus. The unknown bacterium was readily distinguished from these species by using phenotypic methods. On the basis of phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Rhodococcus jostii sp. nov. The type strain is strain IFO 16295T (= CCM 4760T).
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Paenibacillus chinjuensis sp. nov., a novel exopolysaccharide-producing bacterium.
More LessA novel exopolysaccharide-producing bacterium (WN9T) was isolated from Chinju, Korea, and was identified as a member of the genus Paenibacillus on the basis of phenotypic characteristics and phylogenetic inference based on 16S rDNA sequence. This organism is a facultatively anaerobic, endospore-forming rod. The diamino acid found in the peptidoglycan is meso-diaminopimelic acid. The predominant menaquinone is MK-7. The major cellular fatty acid is anteiso-C15:0. The G+C content is 53 mol%. The phylogenetic tree shows that strain WN9T falls within the radiation of a cluster comprising the Paenibacillus species. The levels of 16S rDNA similarity between strain WN9T and the type strains of validly described Paenibacillus species are 92.1-95.8%. Strain WN9T is clearly distinguishable from some phylogenetically related Paenibacillus species on the basis of DNA-DNA relatedness data and phenotypic characters. Therefore, on the basis of these data, a novel species of the genus Paenibacillus, Paenibacillus chinjuensis sp. nov., is proposed. The type strain is strain WN9T (= KCTC 8951PT = JCM 10939T).
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Reclassification of Eubacterium formicigenerans Holdeman and Moore 1974 as Dorea formicigenerans gen. nov., comb. nov., and description of Dorea longicatena sp. nov., isolated from human faeces.
More LessTwo strains of a gram-positively staining, obligately anaerobic, non-spore-forming, rod-shaped bacterium, designated strains 111-13A and 111-35T, were isolated from human faeces. Analysis of the 16S rRNA gene sequences indicated that these strains were members of the Clostridium coccoides rRNA group of organisms. The nearest relatives of the unknown bacterium were Eubacterium formicigenerans (having a sequence similarity of 94%) and an uncultured bacterium (similarity > 99%). Characterization studies indicated that the unidentified faecal bacterium was biochemically distinct from Eubacterium formicigenerans, members of the Clostridium coccoides group and all other described Eubacterium species. On the basis of the data from these studies, it is proposed that the hitherto unknown rod-shaped bacterium be designated a species of a novel genus, namely Dorea longicatena gen. nov., sp. nov., and that Eubacterium formicigenerans be transferred to this genus as Dorea formicigenerans gen. nov., comb. nov.
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Ilyobacter insuetus sp. nov., a fermentative bacterium specialized in the degradation of hydroaromatic compounds.
More LessThe mesophilic, anaerobic bacterium strain VenChi2T was isolated with quinic acid (1,3,4,5-tetrahydroxy-cyclohexane-1-carboxylic acid) as the sole source of carbon and energy. Of more than 30 substrates tested, only quinic acid and shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid) were utilized, yielding acetate, propionate, butyrate, H2 and CO2 as fermentation products. Sugars, alcohols, (di-)carboxylic acids, amino acids and aromatic compounds were not fermented and no external electron acceptors were used. Strain VenChi2T is a gram-negative, strictly anaerobic, coccoid rod; it does not employ the classical hydroaromatic pathway of aerobic bacteria for the degradation of hydroaromatic compounds (no aromatic intermediates involved). Comparative 16S and 23S rDNA sequence analyses placed strain VenChi2T in the fusobacteria phylum, with the closest relatives among species of the genera Ilyobacter and Propionigenium. The results indicate that, disregarding the taxonomically misplaced Ilyobacter delafieldii, which is a member of the clostridia, the validly described Ilyobacter and Propionigenium species are phylogenetically intermixed. Based on its phenotypic properties, strain VenChi2T (= DSM 6831T = ATCC BAA-291T) is assigned to the genus Ilyobacter as the type strain of a novel species, Ilyobacter insuetus sp. nov.
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Biochemical and genetic evidence for the transfer of Mycobacterium tuberculosis subsp. caprae Aranaz et al. 1999 to the species Mycobacterium bovis Karlson and Lessel 1970 (approved lists 1980) as Mycobacterium bovis subsp. caprae comb. nov.
More LessWe propose to replace the species designation Mycobacterium tuberculosis subsp. caprae (Aranaz et al. 1999) by Mycobacterium bovis subsp. caprae comb. nov., since isolates of this subspecies share their main growth, biochemical and genetic characteristics with M. bovis and not with M. tuberculosis. These include negative biochemical test results for niacin accumulation and nitrate reduction as well as genetic features like the presence of an M. bovis-specific mutation in the oxyR locus, absence of the mtp40 sequence and a specific mutation in the gyrB gene, all of which have been described as characteristics for the differentiation of M. bovis. The only obvious biochemical character that differentiates the caprae subtype from other M. bovis isolates is susceptibility to pyrazinamide (PZA), which is due to the lack of a single point mutation in the pncA gene. However, susceptibility to PZA among clinical isolates of M. bovis isolates has been reported previously and, thus, may now been explained by a PZA-susceptible subspecies of M. bovis. We conclude that the species designation M. tuberculosis subsp. caprae is misleading and not correct in light of the biochemical and genetic characteristics and propose that the accurate designation of isolates of this subtype is M. bovis subsp. caprae.
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Helicobacter nemestrinae ATCC 49396T is a strain of Helicobacter pylori (Marshall et al. 1985) Goodwin et al. 1989, and Helicobacter nemestrinae Bronsdon et al. 1991 is therefore a junior heterotypic synonym of Helicobacter pylori.
More LessHelicobacter nemestrinae Bronsdon et al. 1991, a gastric helicobacter species isolated from a pigtailed macaque, is thought to be the species most closely related to the important human pathogen Helicobacter pylori. The only available strain of this taxon is the type strain, ATCC 49396T. We sequenced seven housekeeping genes and two flagellin genes for H. nemestrinae ATCC 49396T. If ATCC 49396T were a separate species, these sequences should have been distinct from those of H. pylori. Instead, all sequences clustered together with sequences obtained previously for 20 or more H. pylori isolates from diverse geographical locations. The 16S rDNA sequence differed from that reported previously for this strain by 38 nucleotides and was most similar to that of H. pylori 85D08 (accession no. U00769), which was isolated from a rhesus macaque. It differed by less than 1% from 16S rDNA sequences of numerous other H. pylori strains, including the type strain, NCTC 11637T (= ATCC 43504T). These data indicate that the strain currently distributed as H. nemestrinae ATCC 49396T is really a strain of H. pylori and that H. nemestrinae Bronsdon et al. 1991 is a junior heterotypic synonym of Helicobacter pylori (Marshall et al. 1985) Goodwin et al. 1989.
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Propionivibrio limicola sp. nov., a fermentative bacterium specialized in the degradation of hydroaromatic compounds, reclassification of Propionibacter pelophilus as Propionivibrio pelophilus comb. nov. and amended description of the genus Propionivibrio.
More LessStrain GolChi1T, a mesophilic, anaerobic bacterium, was isolated with quinic acid (1,3,4,5-tetrahydroxy-cyclohexane-1-carboxylic acid) as the sole source of carbon and energy. Of more than 30 substrates tested, only the hydroaromatic compounds quinic acid and shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid) were utilized, yielding acetate and propionate as the only fermentation products. Sugars, alcohols, (di-)carboxylic acids, amino acids and aromatic compounds were not fermented and no external electron acceptors were used. Strain GolChi1T is a gram-negative, rod-shaped, aerotolerant anaerobe that possesses superoxide dismutase; it does not employ the classical hydroaromatic pathway of aerobic bacteria for the degradation of hydroaromatic compounds (no aromatic intermediates involved). 16S-rRNA-based phylogenetic analyses revealed a common origin of this isolate and Rhodocyclus, Propionibacter and Propionivibrio species. High sequence similarity (> 96%) and phenotypic traits indicated a closer relationship between strain GolChi1T and the type species of the monospecific genera Propionivibrio and Propionibacter but, due to its phenotypic properties, strain GolChi1T could not be assigned conclusively to either of these taxa. We propose (i) the amended description of the genus Propionivibrio, (ii) the reclassification of Propionibacter pelophilus Meijer et al. 1999 as Propionivibrio pelophilus comb. nov. and (iii) designation of Propionivibrio limicola sp. nov., with the type strain GolChi1T (= DSM 6832T = ATCC BAA-290T).
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Classification of three airborne bacteria and proposal of Hymenobacter aerophilus sp. nov.
Three aerobic, gram-negative, rod-shaped, non-spore-forming, red-pigmented, airborne bacteria (I/26-Cor1T, I/32A-Cor1 and I/74-Cor2) collected in the Museo Correr (Venice, Italy) were investigated to determine their taxonomic status by analysing their biochemical, physiological and chemotaxonomic features and the G+C content of genomic DNA and by comparing their genomic fingerprints. Additionally, the almost complete 16S rRNA gene sequence of strain I/26-Cor1T was analysed. The three strains were nearly identical in their morphological, physiological, biochemical and chemotaxonomic properties. The strains contained a menaquinone system with the predominant menaquinone MK-7 and a fatty acid profile with C15:0 anteiso, C15:0 iso and C16:1 predominant. Phosphatidylethanolamine and several unidentified lipids were detected in the polar lipid profiles. The polyamine pattern consisted of sym-homospermidine as the major compound. meso-Diaminopimelic acid was found as the characteristic cell-wall diamino acid. The DNA base composition of the three strains ranged from 60 to 63 mol% G+C. Phylogenetically, strain I/26-Cor1T was most closely related to Hymenobacter actinosclerus (95.8% 16S rRNA gene sequence similarity). Physiological and genomic characteristics indicated that the two strains I/26-Cor1T and I/32A-Cor1 are representatives of the same species. The phylogenetic distance to any validly described taxon as indicated by 16S rRNA gene sequence similarities demonstrates that I/26-Cor1T and I/32A-Cor1 represent a novel species, for which the name Hymenobacter aerophilus sp. nov. is proposed, with the type strain I/26-Cor1T (= DSM 13606T = LMG 19657T). I/32A-Cor1 (= DSM 13607 = LMG 19658) is another strain of the species Hymenobacter aerophilus. Since the taxonomic status of strain I/74-Cor2 within the genus Hymenobacter was not determined unambiguously, it is designated Hymenobacter sp. I/74-Cor2 (= DSM 13611 = LMG 19659).
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Identification of isolates from soybean nodules in Xinjiang Region as Sinorhizobium xinjiangense and genetic differentiation of S. xinjiangense from Sinorhizobium fredii.
More LessEight fast-growing rhizobial isolates from Xinjiang soils were identified as Sinorhizobium xinjiangense by analyses of 16S rRNA gene sequences, SDS-PAGE of proteins, intergenic spacer sequences and DNA-DNA hybridization. Based on all of the results, these isolates and the reference strains for S. xinjiangense were a distinct genomic species, although the 16S rRNA genes were closely related to that of Sinorhizobium fredii.
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Species distinction of the ascomycetous heterothallic yeast-like fungus Stephanoascus ciferrii complex: description of Candida allociferrii sp. nov. and reinstatement of Candida mucifera Kocková-Kratochvílová et Sláviková.
More LessThe nucleotide sequences of the 18S rRNA gene (rDNA) from nine strains of the heterothallic ascomycetous Stephanoascus ciferrii complex were determined and the strains were separated into three groups according to their sequences. 18S rDNA sequences were identical within the same group. In group A the 18S rDNA sequences had no introns; in group B there was one group I intron, Sc1506-1 at position 1506; and in group C there were two group I introns, Sc943 at position 943 and Sc1506-2 at position 1506. Sc1506-1 and Sc1506-2 at position 1506 exhibited 19 base differences but were very similar. Therefore, it is suggested that these introns existed in the common ancestor of groups B and C, and that they were vertically inherited. DNA similarity values showed that the strains within the same group were of identical species. Group B included the isotype strains of Stephanoascus ciferrii and the type strains of Candida ciferrii and Sporothrix catenata; this confirmed that group B strains correspond to Stephanoascus ciferrii and that Candida ciferrii and Sporothrix catenata are synonyms of Stephanoascus ciferrii. The single member of group C, strain IFO 10918T, corresponds to the type strain of Candida mucifera and was independent of the other tested strains. Thus, Candida mucifera should be regarded as an independent species from Stephanoascus ciferrii. It is suggested that group A strains might comprise a new Stephanoascus species, but since group A strains could not form asci by themselves in this study they are described as a new species for which the name Candida allociferrii sp. nov. (type strain IFO 10194T) is proposed.
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Thermomonas haemolytica gen. nov., sp. nov., a gamma-proteobacterium from kaolin slurry.
Four aerobic, gram-negative bacterial strains isolated from kaolin slurry used in the production of paper were subjected to a polyphasic analysis and characterization to determine their taxonomic position. Analysis of the 16S rDNA sequences of the four strains revealed that they represent a new lineage within the gamma-Proteobacteria, related to the genera Xanthomonas, Pseudoxanthomonas, Stenotrophomonas, Luteimonas, Xylella and Rhodanobacter. Analysis of the quinone system, the polyamines, the fatty acids and the polar lipids revealed a combination of characteristics that is unique and not described for the phylogenetic relatives. The four strains contain a ubiquinone Q-8, spermidine as the major polyamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine as the predominant polar lipids, and a fatty acid profile with predominantly iso-branched fatty acids. The G+C content of the genomic DNA was determined to be within the narrow range 67.1-68.7 mol%. Determination of DNA relatedness, as well as riboprint band patterns and amplified fragment length polymorphism profiles, clearly demonstrated that the four strains are members of a single species. Antibiotic-susceptibility patterns were identical for the four strains. Although showing a high degree of similarites in physiological and biochemical patterns, each of the four strains could be distinguished from the others on the basis of a few biochemical characteristics. On the basis of the estimates of phylogenetic relationships derived from the 16S rDNA sequence analyses, the observed chemotaxonomic characteristics and other phenotypic traits, a new genus, Thermomonas gen. nov., and species, Thermomonas haemolytica sp. nov., are proposed for the strains A50-7-3T (= DSM 13605T = LMG 19653T), B 50-7-1 (= DSM 13598 = LMG 19655), D50-7-1 (= DSM 13610 = LMG 19656) and B50-8-1 (= DSM 13599 = LMG 19654), with strain A50-7-3T as the type strain.
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Volumes and issues
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Volume 73 (2023)
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Volume 72 (2022 - 2023)
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Volume 71 (2020 - 2021)
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Volume 70 (2020)
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Volume 69 (2019)
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Volume 68 (2018)
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Volume 67 (2017)
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Volume 65 (2015)
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Volume 50 (2000)
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Volume 49 (1999)
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Volume 48 (1998)
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Volume 47 (1997)
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Volume 46 (1996)
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Volume 45 (1995)
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Volume 44 (1994)
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Volume 43 (1993)
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Volume 42 (1992)
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Volume 41 (1991)
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Volume 40 (1990)
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Volume 39 (1989)
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Volume 38 (1988)
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Volume 37 (1987)
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Volume 36 (1986)
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Volume 35 (1985)
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Volume 34 (1984)
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Volume 33 (1983)
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Volume 32 (1982)
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Volume 31 (1981)
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Volume 30 (1980)
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Volume 29 (1979)
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Volume 28 (1978)
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Volume 27 (1977)
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Volume 26 (1976)
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Volume 25 (1975)
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Volume 24 (1974)
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Volume 23 (1973)
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Volume 22 (1972)
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Volume 21 (1971)
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Volume 20 (1970)
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Volume 19 (1969)
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Volume 18 (1968)
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Volume 17 (1967)
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Volume 16 (1966)
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Volume 15 (1965)
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Volume 14 (1964)
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Volume 13 (1963)
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Volume 12 (1962)
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Volume 11 (1961)
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Volume 10 (1960)
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Volume 9 (1959)
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Volume 8 (1958)
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Volume 7 (1957)
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Volume 6 (1956)
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Volume 5 (1955)
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Volume 4 (1954)
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Volume 3 (1953)
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Volume 2 (1952)
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Volume 1 (1951)
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