Budding Bacteria Research Articles

Microbial consortium involved in ferromanganese and francolite biomineralization in an anchialine environment (Zinzulùsa Cave, Castro, Italy)

Tidally-influenced subterranean settings represent natural geomicrobiological laboratories, relatively unexplored, that facilitate the investigation of new biomineralization processes. The unusual water chemistry of Zinzulùsa Cave and its oligotrophic and aphotic conditions have allowed the development of a unique ecosystem in which complex bacterial activities induce rare biomineralization processes. A diversified microbial community develops on centimeter-thick crusts that form in the submerged part of the cave. The crusts are formed of Ca-phosphate minerals, mostly carbonate-fluoroapatite (francolite), covered by a black crust, few microns in thickness, composed of ferromanganiferous oxides (hematite and vernadite). Diffuse coccoidal and filamentous bacteria and amorphous organic matter are mixed with the minerals. The micromorphologies and comparative 16S rRNA gene-based metabarcoding analyses identify a “core microbiota” also common to other natural environments characterized by FeMn and Ca-phosphate mineralization. The microbiota is characterized by nitrifying, sulfide/sulfur/thiosulfate-oxidizing and sulfate/thiosulfate/sulfur-reducing bacteria. In addition, manganese-oxidizing bacteria include the recently described “Ca. Manganitrophus noduliformans” and an abundance of bacteria belonging to the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) superphylum, as well as Haliangiales (fruiting body-forming bacteria) and Hyphomicrobiales (stalked and budding bacteria) that are known to produce extracellular polymers that trap iron and manganese oxides. 16S rRNA gene metabarcoding analysis showed the presence of bacteria able to utilize many organic P substrates, including Ramlibacter, and SEM images revealed traces of fossilized microorganisms resembling “cable bacteria”, which may play a role in Ca-phosphate biomineralization. Overall, the data indicate biomineralization processes induced by microbial metabolic activities for both ferromanganiferous oxide and francolite components of these crusts.

Starkeya nomas sp. nov., a prosthecate and budding bacterium isolated from an immunocompromized patient.

Strain HF14-78462T is an environmental bacterium found in clinical samples from an immunocompromized patient in 2014 at Hospital Universitari i Politècnic La Fe (Valencia, Spain). Phenotypically, strain HF14-78462T cells were Gram-stain-negative, aerobic, non-spore forming and non-motile small rods which formed mucous and whitish-translucent colonies when incubated at 20-36 °C. Phylogenetic analyses based on the 16S rRNA genes and the whole genomes of closest sequenced relatives confirmed that strain HF14-78462T is affiliated with the genus Starkeya. The strain was oxidase, catalase and urease positive; but indole, lysine decarboxylase, ornithine decarboxylase and DNase negative, did not produce H2S and was able to utilize a wide variety of carbon sources including acetamide, adonitol, amygdalin, l-arabinose, citric acid, glucose, mannitol and melibiose. Unlike Starkeya novella and Starkeya koreensis, strain HF14-78462T failed to grow in thiosulphate-oxidizing media and had a narrower temperature growth range. Its genome was characterized by a size of 4.83 Mbp and a C+G content of 67.75 mol%. Major fatty acids were C18:1 ω7c, cyclo C19 : 0 and C16 : 0, its polar acids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an aminophospholipid; while the ubiquinones were Q9 (1.8 %) and Q10 (98.2 %). Digital DNA-DNA hybridization values were 41 and 41.4 against S. novella and S. koreensis, respectively, while average nucleotide identity values were around 84 %. Phenotypic, average nucleotide identity and phylogenomic comparative studies suggest that strain HF14-78462T is a new representative of the genus Starkeya and the name Starkeya nomas sp. nov. is proposed. The type strain is HF14-78462T (=CECT 30124T=LMG 31874T).

Integrative and quantitative view of the CtrA regulatory network in a stalked budding bacterium.

The Alphaproteobacteria show a remarkable diversity of cell cycle-dependent developmental patterns, which are governed by the conserved CtrA pathway. Its central component CtrA is a DNA-binding response regulator that is controlled by a complex two-component signaling network, mediating distinct transcriptional programs in the two offspring. The CtrA pathway has been studied intensively and was shown to consist of an upstream part that reads out the developmental state of the cell and a downstream part that integrates the upstream signals and mediates CtrA phosphorylation. However, the role of this circuitry in bacterial diversification remains incompletely understood. We have therefore investigated CtrA regulation in the morphologically complex stalked budding alphaproteobacterium Hyphomonas neptunium. Compared to relatives dividing by binary fission, H. neptunium shows distinct changes in the role and regulation of various pathway components. Most notably, the response regulator DivK, which normally links the upstream and downstream parts of the CtrA pathway, is dispensable, while downstream components such as the pseudokinase DivL, the histidine kinase CckA, the phosphotransferase ChpT and CtrA are essential. Moreover, CckA is compartmentalized to the nascent bud without forming distinct polar complexes and CtrA is not regulated at the level of protein abundance. We show that the downstream pathway controls critical functions such as replication initiation, cell division and motility. Quantification of the signal flow through different nodes of the regulatory cascade revealed that the CtrA pathway is a leaky pipeline and must involve thus-far unidentified factors. Collectively, the quantitative system-level analysis of CtrA regulation in H. neptunium points to a considerable evolutionary plasticity of cell cycle regulation in alphaproteobacteria and leads to hypotheses that may also hold in well-established model organisms such as Caulobacter crescentus.

Two-step chromosome segregation in the stalked budding bacterium Hyphomonas neptunium

Chromosome segregation typically occurs after replication has finished in eukaryotes but during replication in bacteria. Here, we show that the alphaproteobacterium Hyphomonas neptunium, which proliferates by bud formation at the tip of a stalk-like cellular extension, segregates its chromosomes in a unique two-step process. First, the two sister origin regions are targeted to opposite poles of the mother cell, driven by the ParABS partitioning system. Subsequently, once the bulk of chromosomal DNA has been replicated and the bud exceeds a certain threshold size, the cell initiates a second segregation step during which it transfers the stalk-proximal origin region through the stalk into the nascent bud compartment. Thus, while chromosome replication and segregation usually proceed concurrently in bacteria, the two processes are largely uncoupled in H. neptunium, reminiscent of eukaryotic mitosis. These results indicate that stalked budding bacteria have evolved specific mechanisms to adjust chromosome segregation to their unusual life cycle.

Mn-Fe-Enhancing Budding Bacteria in Century-Old Rock Varnish, Erie Barge Canal, New York

AbstractFossil remnants of bacteria involved in the enhancement of manganese and iron rarely occur within the microstratigraphy of rock varnishes collected from warm desert environments, because varnish formation processes ultimately destroy these microfossils through remobilization of Mn-Fe and reprecipitation in a clay-mineral matrix. In contrast, Mn-Fe encrustations on budding bacteria commonly occur within varnishes that formed within just a century along the Erie Barge Canal, New York. Nanoscale imagery and elemental analyses reveal that these budding bacterial forms greatly enhance Mn, Fe, or both in encrustations surrounding hyphae and cells. The Mn and Fe precipitates have a granular texture on the scale of <1 nm to ∼10 nm. The precipitates also have a stringy texture, where strings are typically only a few nanometers wide. These in situ observations are consistent with expectations from studies of budding-bacteria cultures and with the polygenetic model of varnish formation. Given that the Erie C...

Roseovarius antarcticus sp. nov., isolated from a decayed whale bone.

A pale yellow, ovoid- to rod-shaped and budding bacterium, designated strain M-S13-148(T), was isolated from a decayed bone of whale from the eastern coast of King George Island, South Shetlands, Antarctica. Strain M-S13-148(T) exhibited motility, aerobic growth and was Gram-stain-negative. Strain M-S13-148(T) was positive for catalase and oxidase. Growth was observed at pH 6.0-9.0, at 4-42 °C and with 0-14% (w/v) NaCl. The novel strain contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unknown phospholipid as the major polar lipids. The dominant cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), (58.8%) and C16 : 0 (11.7%). The respiratory quinone was Q-10 and the DNA G + C content was 60.9 mol%. Neighbour-joining, maximum-likelihood and minimum-evolution phylogenetic trees, based on 16S rRNA gene sequences, indicated that strain M-S13-148(T) belonged to the genus Roseovarius and was most closely related to Roseovarius nanhaiticus CCTCC AB 208317(T) (93.72% 16S rRNA gene sequence similarity). The 16S rRNA gene sequence similarity with respect to members of the genus Roseovarius ranged from 91.81 to 93.94%. On the basis of phenotypic, molecular and chemotaxonomic characteristics, strain M-S13-148 is considered to represent a novel species of the genus Roseovarius, for which the name Roseovarius antarcticus sp. nov., is proposed. The type strain is M-S13-148(T) ( = CCTCC AB2014072(T) = LMG 28420(T)).

Preparatory work for the pest categorisation of three bacteria listed in the annexes of the Council directive 2000/29/EC Erwinia amylovora Winslow et al. Xylophilus ampelinus (Panagopoulos) Willems et al. Clavibacter michiganensis subsp. insidiosus(McCulloch) Davis et al

Preparatory work for the pest categorisation of three bacteria listed in the annexes of the Council directive 2000/29/EC Erwinia amylovora Winslow et al. Xylophilus ampelinus (Panagopoulos) Willems et al. Clavibacter michiganensis subsp. insidiosus(McCulloch) Davis et al

Uso de antibióticos para o controle de bactérias endógenas visando à micropropagação da figueira

A descontaminação dos explantes é um dos princípios básicos para o sucesso da cultura de tecidos. Um dos problemas diagnosticados na propagação in vitro da figueira, através de gemas apicais, é a contaminação endógena dos explantes por bactérias. Este trabalho teve como objetivo avaliar a eficiência de alguns antibióticos em meio de cultura para o controle de bactérias endógenas em gemas apicais de figueira. Foram avaliados os seguintes tratamentos: T1(sem adição de antibiótico); T2 (30 mg L-1 de cloranfenicol); T3 (250 mg L-1 de ampicilina sódica); T4 (500 mg L-1 de ácido nalidícico); T5 (150 mg L-1 de cefalotina sódica); T6 (500 mg L-1 de tetraciclina), e T7 (400 mg L-1 de norfloxacina). Após coletados em campo, os segmentos de ramos contendo as gemas foram colocados em recipiente com água corrente. Posteriormente, as gemas apicais foram imersas em álcool etílico a 70% e hipoclorito de sódio a 2,5%. Todo procedimento de desinfestação externa dos explantes foi realizado em câmara de fluxo laminar. Os explantes foram inoculados em tubos de ensaio contendo 15 mL de meio básico MS suplementado, após a autoclavagem, com as doses de antibióticos de acordo com os tratamentos estabelecidos. Após a inoculação, os explantes foram mantidos em sala de crescimento por quatro dias no escuro e, em seguida, sob fotoperíodo de 16 horas de luz branca fria e irradiância de 25 µmol m s-1, na temperatura de 22 ± 3ºC. A assepsia realizada externamente nos explantes foi suficiente para o controle de contaminação fúngica, e a adição de antibióticos ao meio, após autoclavagem, foi eficiente para o controle de bactérias endógenas, cujo antibiótico ampicilina sódica proporcionou mais de 90% de explantes sobreviventes.

Singulispaera mucilagenosa sp. nov., a novel acid-tolerant representative of the order Planctomycetales

Two novel strains of budding bacteria, Z-0071T and Z-0072, were isolated from dystrophic humified waters formed by xylotrophic fungi in the course of spruce wood degradation. The cells of both strains are coccoid (0.95–1.80 μm), nonmotile, single or arranged in pairs. The cells have a complex system of intracellular membranes and are covered with fimbriae and surrounded by a mucous capsule up to 0.3 μm thick. Both strains are aerobic organoheterotrophic, mesophilic, and acid-tolerant microorganisms that are able to grow under microaerobic conditions. They utilize N-acetyl-glucosamine, carbohydrates, and lactate as growth substrates. The strains grow in a pH range of 4.0–7.5 with an optimum at 6.0–6.5. The temperature range for growth is 4–30°C, with an optimum at 25–28°C. Strains Z-0071T and Z-0072, inhabitants of dystrophic low-mineral waters, are NaCl-sensitive: the NaCl content in the media above 0.5 g/l inhibited growth. The main fatty acids of strains Z-0071T and Z-0072 are C16:0, C18:1ω9c, and C18:2ω9c, 12c. The DNA G + C base content is 51.2–51.7 mol %. The sequences of the 16S rRNA gene fragments (1310 bp) of strains Z-0071T and Z-0072 were found to be identical. The obtained sequences showed a 94.3% similarity with the sequences of the type strain of the most closely related species Singulisphaera acidiphila MOB10≅T. The phenotypic and phylogenetic properties of strains Z-0071T and Z-0072 support classification of these strains within the genus Singulisphaera as a new species Singulisphaera mucilagenosa sp. nov., with the type strain Z-0071T (VKM B-2626).

Detecção de bactérias associadas a gemas de pereiras europeias no Rio Grande do Sul

A morte de flores em pomares de pereiras europeias (Pyrus communis L.) foi observada em Vacaria, RS. Dois isolados bacterianos, oriundos de flores sintomaticas, reproduziram tais sintomas em flores de ramos destacados e foram identificados como Pseudomonas sp. Devido a ausencia de registro da etiologia dessa doenca no Brasil, ao registro de P. syringae pv. syrigae e Erwinia amylovora associadas a sintomas similares em outros paises e a possivel presenca deste tipo de bacterias em gemas, um metodo para deteccao dessas tres bacterias foi desenvolvido. O metodo envolveu maceracao das gemas com nitrogenio liquido, adicao de PBS e PVP 2%, transferencia do suco para cartao FTA (Whatman); tratamento de circulos do cartao, com etanol 70%, reagente FTA e tampao TE, eluicao do DNA seguida de PCR com oligonucleotideos iniciadores especificos para cada uma das bacterias. O metodo foi, entao, utilizado para monitorar tais bacterias em gemas colhidas bimensalmente durante 2008. E. amylovora nao foi detectada. A frequencia media de P. syringae pv. syringae e Pseudomonas sp. foi de 0,7 e 16,3%, respectivamente; a ultima atingindo pico de 30% em outubro. A especie do agente causal nao foi elucidada, mas foi demonstrada a associacao com o genero Pseudomonas, o que ja fornece subsidios para o desenvolvimento de metodos de controle da doenca.

Protein uptake by bacteria

Endocytosis is a fundamental process of membrane-trafficking in eukaryotes, but has not been known to occur in bacteria or archaea. The origin of endocytosis is central to the understanding of evolution of the first eukaryotes and their endomembrane systems. In a recent study we have established that an endocytosis-like process for uptake of proteins into cells occurs in a bacterium, Gemmata obscuriglobus, a member of the distinctive phylum Planctomycetes of peptidoglycan-less budding bacteria. Members of this phylum characteristically possess cells divided into compartments separated by internal membranes, and in the case of G. obscuriglobus these compartments include one where a double membrane envelope surrounds its nucleoid DNA, as well as an outer ribosome-free region of cytoplasm. Proteins can be internalized by cells from the external milieu and collected into this ribosome-free compartment, and this process is energy-dependent and appears to be receptor-mediated. As in eukaryote endocytosis, internalized proteins are associated with vesicles, and can be subjected to proteolytic degradation. The discovery of this process in a bacterium has significant implications for our understanding of the origins of endocytosis in eukaryotes.

Labrys wisconsinensis sp. nov., a budding bacterium isolated from Lake Michigan water, and emended description of the genus Labrys

Two facultatively anaerobic, budding bacterial strains, designated W1215-PCA4(T) and SRNK-1, were isolated from water from Lake Michigan, USA. The two strains showed identical ERIC-PCR-generated genomic fingerprints and shared 99.9 % 16S rRNA gene sequence similarity. Strain W1215-PCA4(T) showed highest 16S rRNA gene sequence similarities to Labrys monachus VKM B-1479(T) (95.8 %), Labrys methylaminiphilus DSM 16812(T) (95.1 %), Labrys okinawensis MAFF 210191(T) (96.0 %), Labrys miyagiensis G24103(T) (95.4 %), Labrys neptuniae BCRC 17578(T) (95.7 %) and Labrys portucalensis DSM 17916(T) (95.8 %). Data suggested that the two strains were members of a single novel species of the genus Labrys. The major cellular fatty acids of the two isolates were C(18 : 1)omega7c, C(19 : 0) cyclo omega8c and C(16 : 0). Their polar lipid profiles were highly similar to that of Labrys monachus DSM 5896(T). The primary quinone was ubiquinone Q-10, with minor amounts of Q-9 and Q-11. sym-Homospermidine was the predominant polyamine, with putrescine present in moderate amounts. The two strains were identical in terms of their biochemical and physiological traits, but were distinguishable from other species of the genus Labrys. Hence, the description of a novel species in this genus appears to be justified. The name Labrys wisconsinensis sp. nov. is proposed; the type strain is W1215-PCA4(T) (=DSM 19619(T)=NRRL B-51088(T)).

Singulisphaera acidiphila gen. nov., sp. nov., a non-filamentous, Isosphaera-like planctomycete from acidic northern wetlands

Four novel strains of budding bacteria, designated MOB10T, PO2, MPL1015 and BG32, were isolated from acidic wetlands of northern Russia. Cells of these four strains were aerobic, non-motile spheres that occurred singly or in shapeless aggregates and attached to surfaces by means of a holdfast material. The isolates were moderately acidophilic, mesophilic organisms capable of growth between pH 4.2 and 7.5 (optimum growth at pH 5.0-6.2) and at temperatures between 4 and 33 degrees C (optimum growth at 20-26 degrees C). The strains possessed a complex intracellular membrane system that compartmentalized the cells. The major fatty acids were C16 : 0, C18 : 1omega9c and C18 : 2omega6c,12c. The major quinone was menaquinone-6 (MK-6). The G+C content of the DNA was 57.8-59.9 mol%. 16S rRNA gene sequence analysis showed that strains MOB10T, PO2, MPL1015 and BG32 were members of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Isosphaera, exhibiting 90 % sequence similarity to the type strain of the thermophilic planctomycete Isosphaera pallida and 95-95.5 % sequence similarity to a taxonomically uncharacterized group of filamentous bacteria from activated sludge, 'Nostocoida limicola' III. However, compared with 'Nostocoida limicola' III and Isosphaera pallida, the new isolates from acidic wetlands were non-filamentous, unpigmented bacteria, which possessed highly distinctive phospholipid fatty acid profiles and were capable of growth and of degrading several biopolymers under acidic, microaerobic and cold conditions. The data suggest that the four isolates should be considered as representing a novel species of a new genus of the order Planctomycetales, for which the name Singulisphaera acidiphila gen. nov., sp. nov. is proposed. The type strain of Singulisphaera acidiphila is MOB10T (=ATCC BAA-1392T =VKM B-2454T =DSM 18658T).

Formosa agariphila sp. nov., a budding bacterium of the family Flavobacteriaceae isolated from marine environments, and emended description of the genus Formosa

Two marine, heterotrophic, aerobic, yellow-pigmented, agarolytic bacterial strains that are motile by means of gliding were isolated from the green alga Acrosiphonia sonderi and from sea water. Comparative 16S rRNA gene sequence analysis revealed an affiliation between the strains studied and the genus Formosa, a member of the family Flavobacteriaceae. The level of sequence similarity between strain KMM 3901T and Formosa algae KMM 3553T was 99.1 %. The results of DNA-DNA hybridization experiments and phenotypic analysis indicated that the strains represent a novel species of the genus Formosa, for which the name Formosa agariphila sp. nov. is proposed, with KMM 3901T (= KCTC 12365T = LMG 23005T = DSM 15362T) as the type strain. The description of the genus Formosa is emended with newly obtained data.

Proposal for combining Bradyrhizobium spp. ( Aeschynomene indica) with Blastobacter denitrificans and to transfer Blastobacter denitrificans (Hirsch and Muller, 1985) to the genus Bradyrhizobium as Bradyrhizobium denitrificans (comb. nov.)

The symbiotic bradyrhizobia of Aeschynomene indica and the aquatic budding bacterium Blastobacter denitrificans have much in common and this study broadens the characters that are shared between the two. The 23S rRNA gene sequences of the bradyrhizobial isolates were most similar to each other and to the sequence of Bl. denitrificans. Evidence for the presence of photosynthetic genes in the genome of Bl. denitrificans was obtained by PCR using primers to the conserved M subunit ( pufM) of the photosynthetic reaction center present in purple sulfur and purple nonsulfur bacteria. The deduced amino acid sequences of the partial PufM protein of Bl. denitrificans and the corresponding sequences obtained from the bradyrhizobial isolates were identical. Both the bradyrhizobial isolates and the type strain of Bl. denitrificans shared the ability to propagate by budding, demonstrated by electron microscopy. Even though many interspecific characters were shared among the bradyrhizobial isolates including Bl. denitrificans, it was evident from Amplified Fragment Length Polymorphism (AFLP) analysis that genomic variation existed among the collection that was examined. Variation among bradyrhizobial isolates and Bl. denitrificans also was established in carbon and nitrogen source utilization and the ability to grow at elevated temperature. Based on these results and previously reported evidence it is suggested that the type strain for Bl. denitrificans and the bradyrhizobial isolates from nodules of A. indica belong to a common group of bacteria. Therefore, it is proposed that they be combined into the genus Bradyrhizobium and that LMG 8443 be transferred to this genus as the type strain for B. denitrificans.

Taxonomic heterogeneity within the Planctomycetales as derived by DNA-DNA hybridization, description of Rhodopirellula baltica gen. nov., sp. nov., transfer of Pirellula marina to the genus Blastopirellula gen. nov. as Blastopirellula marina comb. nov. and emended description of the genus Pirellula.

Ninety-seven strains of budding bacteria originating from various aquatic habitats and morphologically resembling planctomycetes were investigated taxonomically. Taxonomic differentiation was based on DNA-DNA hybridization, physiological properties and chemotaxonomic tests. Nineteen hybridization groups, containing 79 of the tested strains, were established. Eighteen strains, however, did not fit into any of these groups. Rhodopirellula baltica gen. nov., sp. nov. is described, with strain SH 1T (= IFAM 1310T = DSM 10527T = NCIMB 13988T) as the type strain. Pirellula marina is transferred to the genus Blastopirellula gen. nov. as Blastopirellula marina comb. nov., with strain SH 106T (= IFAM 1313T = DSM 3645T = ATCC 49069T) as the type strain. An emended description of the genus Pirellula is also provided. Differentiation between R. baltica, B. marina and Pirellula staleyi was achieved by the integration of morphological, physiological, chemotaxonomic and genetic characteristics.

Oceanicaulis alexandrii gen. nov., sp. nov., a novel stalked bacterium isolated from a culture of the dinoflagellate Alexandrium tamarense (Lebour) Balech.

Five bacterial strains were isolated from a non-toxigenic strain of the marine dinoflagellate Alexandrium tamarense (Lebour) Balech CCMP 116 (NEPCC C116), during a survey of the diversity of bacteria associated with paralytic shellfish toxin-producing cultures of Alexandrium spp. (Dinophyta). All strains were strictly aerobic, Gram-negative, straight or curved rods. Cells were dimorphic, with stalks (or prosthecae) and non-motile or non-stalked and motile, by means of a single polar flagellum. The bacteria grew best at salt concentrations ranging from 2 to 10 % and growth occurred at 10 degrees C, but not at 50 degrees C. The G+C content of the chromosomal DNA of the strains was determined to be 61-62 mol%. Major cellular fatty acids of the bacteria presented a unique profile. 16S rRNA gene sequence analysis showed the five strains to be related to genera of budding bacteria of marine origin in the 'Alphaproteobacteria', namely, Hirschia, Maricaulis and Hyphomonas, although they exhibited substantial differences in morphology, substrate utilization and fatty acid profile to members of these genera. The five strains are proposed to comprise a new species of a new genus, Oceanicaulis alexandrii gen. nov., sp. nov., the type strain of which is C116-18(T) (=DSM 11625(T)=NCIMB 13905(T)).

Detection of intracellular bacteria in the buds of Scotch pine (Pinus sylvestris L.) by in situ hybridization.

Bacterial isolates were obtained from pine (Pinus sylvestris L.) tissue cultures and identified as Methylobacterium extorquens and Pseudomonas synxantha. The existence of bacteria in pine buds was investigated by 16S rRNA in situ hybridization. Bacteria inhabited the buds of every tree examined, primarily colonizing the cells of scale primordia and resin ducts.

Hyphomonas adhaerens sp. nov., Hyphomonas johnsonii sp. nov. and Hyphomonas rosenbergii sp. nov., marine budding and prosthecate bacteria.

Three strains of prosthecate, budding bacteria, MHS-2T, MHS-3T and VP6T, were isolated from marine habitats including the open ocean (the pelagic zone), the offshore region (the neritic zone) and the hydrothermal vent region. A polyphasic approach including 16S rDNA sequencing, phenotypic analyses, serology, fatty acid analyses, membrane protein profiles and DNA-DNA hybridizations was used to place these strains in the genus Hyphomonas, a taxon of the alpha-Proteobacteria. The results of these analyses also showed that strains MHS-3T, MHS-2T and VP6T each represent a new species of Hyphomonas. The names Hyphomonas adhaerens (type strain MHS-3T, ATCC 43965T), Hyphomonas johnsonii (type strain MHS-2T, ATCC 43964T) and Hyphomonas rosenbergii (type strain VP6T, ATCC 43869T) are proposed for the new species. With these additions, Hyphomonas now contains eight species.

Staleya guttiformis gen. nov., sp. nov. and Sulfitobacter brevis sp. nov., alpha-3-Proteobacteria from hypersaline, heliothermal and meromictic antarctic Ekho Lake.

Two Gram-negative, aerobic, pointed and budding bacteria were isolated from various depths of hypersaline, heliothermal and meromictic Ekho Lake (Vestfold Hills, East Antarctica). 16S rRNA gene sequence comparisons show the isolates to be phylogenetically close to the genera Sulfitobacter and Roseobacter. Cells can be motile and contain storage granules. Sulfite addition does not stimulate growth. Isolate EL-38T can produce bacteriochlorophyll a and has a weak requirement for sodium ions; polar lipids include phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified amino lipid, but not diphosphatidylgycerol. The dominant fatty acid is 18:1omega7c; other characteristic fatty acids are 3-OH 10:0, 3-OH 14:1, 16:0, 18:0, 18:2 and 19:1. The DNA base composition is 55.0-56.3 mol% G+C. Isolate EL-162T has an absolute requirement for sodium ions. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified amino lipid are present in the polar lipids. Dominant fatty acids of this isolate are 18:1omega7c and 18:1omega9c as well as 18:2 which is present as two isomers. Other characteristic fatty acids are 3-OH 10:0, 3-OH 14:1, 16:0 and 18:0. The G+C content is 57.9-58.1 mol%. Morphological, physiological and genotypic differences from related, thus far known genera support the description of Staleya guttiformis gen. nov. and sp. nov. with EL-38T (= DSM 11458T) as the type strain and of Sulfitobacter brevis sp. nov. with the type strain EL-162T (= DSM 11443T).