Extracellular endoglucanase activity by a novel bacterium isolated from marine shipworm

An extracellular enzyme preparation from shipworm bacterium cultures dramatically increased reducing sugar content of carboxymethylcellulose (CMC3), but did not solubilize sugar from particulate cellulose. The preparation degraded cellodextrins larger than cellotriose (G3). Only interior cellodextrin chain linkages were cleaved and the center-most bond of cellohexaose (G6) was preferentially cleaved. Activity maxima were observed at 60 degrees C and between pH 5.0 and 7.0. The activity was resistant to protease treatment and little loss of activity was observed after 14 d at 25 degrees C.     

Physiological traits of the symbiotic bacterium Teredinibacter turnerae isolated from the mangrove shipworm Neoteredo reynei

Nutrition in the Teredinidae family of wood-boring mollusks is sustained by cellulolytic/nitrogen fixing symbiotic bacteria of the Teredinibacter clade. The mangrove Teredinidae Neoteredo reynei is popularly used in the treatment of infectious diseases in the north of Brazil. In the present work, the symbionts of N. reynei, which are strictly confined to the host's gills, were conclusively identified as Teredinibacter turnerae. Symbiont variants obtained in vitro were able to grow using casein as the sole carbon/nitrogen source and under reduced concentrations of NaCl. Furthermore, cellulose consumption in T. turnerae was clearly reduced under low salt concentrations. As a point of interest, we hereby report first hand that T. turnerae in fact exerts antibiotic activity. Furthermore, this activity was also affected by NaCl concentration. Finally, T. turnerae was able to inhibit the growth of Gram-negative and Gram-positive bacteria, this including strains of Sphingomonas sp., Stenotrophomonas maltophilia, Bacillus cereus and Staphylococcus sciuri. Our findings introduce new points of view on the ecology of T. turnerae, and suggest new biotechnological applications for this marine bacterium.     

Isolation and characterization of an alkaline protease from the marine shipworm bacterium

Bacterial isolates from the gland of Deshayes of the marine shipworm (Psiloteredo healdi) produced extracellular protease activity when cultured with 1% cellulose. A protease with a relative molecular mass of 36,000 daltons as determined by SDS-PAGE and a pI of 8.6 was isolated from the medium and purified to electrophoretic homogeneity. No carbohydrate appeared to be associated with the protein. The enzyme was activated and stabilized by relatively high salt concentrations (>0.2M). Below 0.1M salt, significant protein aggregation occurred, as well as autohydrolysis of the protease, both of which resulted in the loss of activity. The specific activity of the enzyme was 65,840 proteolytic units/mg with azocasein substrate of optimal temperature (42°C), pH (9.0), and salt concentration (0.20M NaCl). The activity was stable up to 40°C, from pH 3.0 to pH 11.9, and from 0.1M to 3.5M NaCl. These stabilities, as well as the protease's stability in the presence of chelators, oxidizing agents, and heavy metals, suggest the enzyme has potential for use in relatively low temperature (40°C) industrial applications.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Utility of alkaline protease from marine shipworm bacterium in industrial cleansing applications

Summary An alkaline protease, previously isolated from a symbiotic bacterium found in the gland of Deshayes of marine shipworm, was evaluated as a cleansing additive. The protease nearly doubled the cleaning power of a standard phosphate detergent at temperatures up to 50°C as determined by fabric swatch assays. The enzyme was, however, ineffective at 70°C. In both fresh and seawater, it was also an efficient presoak. The cleaning power of a non-phosphate detergent was significantly improved by added protease, independent of the pH range 10 to 12. The enzyme degraded lysozyme, the major protein contaminant of contact lenses, more extensively than subtilisin and was effective in solutions containing hydrogen peroxide, often employed to sterilize lenses. The protease was unusually stable in sodium perborate, as well as hydrogen peroxide, and retained good activity in the presence of sodium hypochloride.     

A novel enzyme, lambda-carrageenase, isolated from a deep-sea bacterium

A lambda-carrageenan-degrading Pseudoalteromonas bacterium, strain CL19, was isolated from a deep-sea sediment sample. A lambda-carrageenase from the isolate was purified to homogeneity from cultures containing lambda-carrageenan as a carbon source. This is the first report of the isolation of lambda-carrageenase together with the gene sequence for the enzyme. The molecular mass of the purified enzyme was approximately 100 kDa on both SDS-PAGE and gel-filtration chromatography, suggesting that the enzyme is a monomer. The optimal pH and temperature for activity were about 7 and 35 degrees C, respectively. The enzyme had specific activity of 253 U/mg protein. The enzyme required monovalent salts for the activity. Carbohydrates, such as sorbitol, sucrose, trehalose, improved the enzyme stability. The pattern of lambda-carrageenan hydrolysis showed that the enzyme is an endo-type lambda-carrageenase, and the final main product was a tetrasaccharide of the lambda-carrageenan ideal structure with galactose 2,6-disulfate at the reducing end, indicating the enzyme cleaves the beta-1,4 linkages of its backbone structure. Furthermore, the gene (cglA) encoding the enzyme was sequenced. It encoded a mature protein of 103 kDa (917 amino acids). Remarkably, the deduced amino acid sequence showed no similarity to any reported proteins.     

Pseudomonas xanthomarina sp. nov., a novel bacterium isolated from marine ascidian

Two Pseudomonas-like yellow-orange-pigmented non-fluorescent denitrifying strains KMM 235 and KMM 1447T were isolated from marine ascidian specimens and investigated by a polyphasic approach to clarify their taxonomic status. On the basis of 16S rDNA gene sequence data the new isolates clustered with the Pseudomonas stutzeri species group with sequence similarities of >98%. The results of DNA-DNA hybridization and biochemical characterization showed genetic and phenotypic distinction between strains KMM 235 and KMM 1447T and from the other validly described Pseudomonas species. Strain KMM 235 was found to be closely related to the type strain of Pseudomonas stutzeri in their phenotypic and genetic characteristics and represented, probably, a new P. stutzeri genomovar. It is proposed that strain KMM 1447T be classified as a new species of the genus Pseudomonas, Pseudomonas xanthomarina sp. nov., with the type strain KMM 1447T (=JCM 12468T=NRIC 0617T=CCUG 46543T).     

Pseudacidovorax intermedius NH-1, a novel marine nitrogen-fixing bacterium isolated from the South China Sea

We have taxonomically and phylogenetically characterized a novel nitrogen-fixing bacterial strain, NH-1, which was recently isolated from surface sediments of the South China Sea. The presence of the nifH gene was determined by PCR amplification. The strain NH-1 was found to belong to the genus Pseudacidovorax based on phenotypic characterization, 16S rDNA sequencing, G+C content and DNA-DNA hybridization. Isolate NH-1 was identified as Pseudacidovorax intermedius. In addition, we investigated the links between environmental factors and the nitrogenase activity of NH-1. We found that the nitrogen fixation capacity of NH-1 varied strongly when cells were grown with different ammonium ion and oxygen concentrations, amino acids and carbohydrates. This is the first report of the isolation of Pseudacidovorax from the ocean and the first study to explore the effects of different culture conditions on the nitrogenase activities of the isolate. This study provides evidence that marine nitrogen-fixing microorganisms are far more diverse than currently recognized.     

Draft genome sequence of Commensalibacter intestini A911T, a symbiotic bacterium isolated from Drosophila melanogaster intestine

Commensalibacter intestini A911(T), a predominant symbiotic bacterium capable of stably colonizing gut epithelia, was isolated from the fruit fly, Drosophila melanogaster. Here we report the draft genome sequence of Commensalibacter intestini A911(T).     

Hoeflea halophila sp. nov., a novel bacterium isolated from marine sediment of the East Sea, Korea

A Gram-negative, aerobic, motile, straight or curved rod-shaped marine bacterium was isolated from marine sediment of the East Sea, Korea. The isolated strain, JG120-1^T, grows with 0–5 % (w/v) NaCl and at 15–30 °C and pH 6–9. α-galactosidase activity test was positive. Comparative 16S rRNA gene sequence studies showed that this strain belonged to the Alphaproteobacteria and was the most closely related to Hoeflea alexandrii AM1 V30^T, Hoeflea phototrophica DFL-43^T and Hoeflea marina LMG 128^T (98.9, 97.9 and 97.0 % 16S rRNA gene sequence similarities, respectively). Strain JG120-1^T was found to possess summed feature 8 (C18:1ω7c/C18:1ω6c, 71.11 %) as the major cellular fatty acid. The major ubiquinone was determined to be Q-10. Polar lipids include phosphatidylglycerol, phosphatidylethanolamine, sulfoquinovosyl diacylglycerol, phosphatidylcholine and phosphatidylmonomethylethanolamine. The G+C content of the genomic DNA of strain JG120-1^T was determined to be 57.8 mol %. DNA–DNA relatedness data indicated that strain JG120-1^T represents a distinct species that is separate from H. phototrophica DFL-43^T, H. marina LMG128^T and H. alexandrii AM1 V30^T. On the basis of polyphasic evidences, it is proposed that strain JG120-1^T (= KCTC 23107^T = JCM 16715^T) represents the type strain of a novel species, Hoeflea halophila sp. nov.     

一株溶藻细菌对海洋原甲藻的溶藻效应

从深圳大鹏湾南澳赤潮爆发海域的表层海水中分离得到1株对海洋原甲藻(Prorocentrum micans)具有溶藻活性的海洋细菌,菌株编号为N10。利用液相感染法研究了该溶藻细菌的溶藻效果和溶藻作用方式。结果表明,菌株N10能使藻细胞失去运动活性,并膨胀变形,细胞膜内物质聚集于一端,藻细胞最终破裂死亡。菌悬液接种到藻液中的量越大,初始细菌密度越高,其溶藻效果越强。菌悬液以1∶10的体积比接种到藻液中时,藻细胞在24 h的死亡率为83%,至72 h全部溶解死亡;体积比为1∶20的藻细胞在24 h的死亡率为71%,之后藻细胞密度略有波动,120 h时死亡率达77%;而体积比为1∶100的藻细胞密度在前24 h有所下降,死亡率达39%,之后藻细胞密度又开始明显上升;对照组的藻细胞密度均呈明显上升趋势。菌悬液过滤液和高温加热处理后的菌悬液过滤液对海洋原甲藻均无溶藻活性,表明菌株N10的溶藻方式为直接溶藻。通过16S rRNA序列分析并与GenBank数据进行同源性检索,并结合细菌形态及生理生化特征,菌株N10隶属于黄杆菌科(Flavobacteriaceae)中的Muricauda sp.。     

A novel cyclopeptide from a bacterium associated with the marine sponge Ircinia muscarum

A new cyclotetrapeptide 1, together with three known cyclopeptides were isolated from the exo-cellular extract of Pseudomonas sp. a bacterium associated with the sponge Ircinia muscarum. The structure of 1 was suggested on the basis of spectroscopic analytical data and chemical degradation.     

Oleispira lenta sp. nov., a novel marine bacterium isolated from Yellow sea coastal seawater in Qingdao, China

The taxonomic position of strain DFH11^T, which was isolated from coastal seawater off Qingdao, People’s Republic of China in 2007, was determined. Strain DFH11^T comprised Gram-negative, motile, strictly aerobic spirilli that did not produce catalase. Comparative 16S rRNA gene sequence analysis revealed that strain DFH11^T shared ~97.2, 93.3, 91.8, 91.7 and 91.5% sequence similarities with Oleispira antarctica, Spongiispira norvegica, Bermanella marisrubri, Oceaniserpentilla haliotis and Reinekea aestuarii, respectively. DNA–DNA hybridization experiments indicated that the strain was distinct from its closest phylogenetic neighbour, O. antarctica. The strain grew optimally in 2–3% (w/v) NaCl, at pH 5.0–10.0 (optimally at pH 7.0) and between 0 and 30°C (optimum growth temperature 28°C). The strain exhibited a restricted substrate profile, with a preference for aliphatic hydrocarbons, that is consistent with its closest phylogenetic neighbour O. antarctica. Growth of the isolate at different temperatures affected the cellular fatty acid profile. 28°C cultured cells contained C_16:1ω7c and/or iso-C_15:0 2-OH (50.4%) and C_16:0 (19.2%) as the major fatty acids. However, the major fatty acids of the cells cultured at 4°C were C_16:1ω7c and/or C_16:1ω6c (40.2%), C_16:0 (17.2%) and C_17:1ω8c (10.1%). The G+C content of the genomic DNA was 42.7 mol%. Phylogeny based on 16S rRNA gene sequences together with data from DNA–DNA hybridization, phenotypic and chemotaxonomic characterization revealed that DFH11^T should be classified as a novel species of the genus Oleispira, for which the name Oleispira lenta sp. nov. is proposed, with the type strain DFH11^T (=NCIMB 14529^T = LMG 24829^T).     

Pseudoxanthomonas kaohsiungensis, sp. nov., a novel bacterium isolated from oil-polluted site produces extracellular surface activity

During screening for biosurfactant-producing bacteria, a strain designated J36T was isolated from oil-polluted site near Kaohsiung city located in southern Taiwan. Cells of this organism were gram-negative rods motile by means of a single polar flagellum. Strain J36T grew well in complex media under optimum conditions of 35 degrees C and pH 7. The extracellular products of the strain expressed emulsification activity. During cultivation on olive oil as the sole carbon and energy source, the culture supernatant of strain J36T reduced surface tension of the medium from 68 to 32.6 dyne/cm. The 16S rRNA gene sequence analysis indicates that strain J36T is a member of Xanthomonas group within the gamma-Proteobacteria. The organism belongs to the genus Pseudoxanthomonas and represents a novel species within this genus according to phylogenetic analysis of 16S rDNA sequences, DNA-DNA similarity data, whole-cell protein analysis, physiological and biochemical characteristics, as well as fatty acid compositions. The predominant cellular fatty acids of strain J36T were 15:0 iso (about 26%), 17:1 iso omega9c (about 25%), and 15:0 anteiso (about 10%). Its DNA base ratio was 60.1 mol% G+C. We propose to classify strain J36T (= BCRC 17375T = LMG 22530T) as Pseudoxanthomonas kaohsiungensis sp. nov.     

Massilia sp. BS-1, a novel violacein-producing bacterium isolated from soil

A novel bacterium, Massilia sp. BS-1, producing violacein and deoxyviolacein was isolated from a soil sample collected from Akita Prefecture, Japan. The 16S ribosomal DNA of strain BS-1 displayed 93% homology with its nearest violacein-producing neighbor, Janthinobacterium lividum. Strain BS-1 grew well in a synthetic medium, but required both L-tryptophan and a small amount of L-histidine to produce violacein.     

Long term starvation of a marine bacterium, Alteromonas denitrificans, isolated from a Norwegian fjord

The marine bacterium Alteromonas denitrificans has survived for up to 7 years in unsupplemented sea water. The relatively low affinities for uptake of arginine and glucose (Kt of 80 and 790 μM, respectively) indicate that A. denitrificans takes up substrates effectively only at high concentrations. This bacterium was starved in artificial seawater alone, with nutrients (ammonium and phosphate) or with energy (glucose or arginine) added.Incorporation of thymidine into DNA decreased rapidly upon starvation, indicating a cessation of DNA synthesis. At the onset of starvation the number of colony-forming units (c.f.u.) increased 3-fold while the cell volume decreased by one-third except in the presence of glucose where the c.f.u. decreased and the volume increased 4-fold. Cells starved in the presence of glucose had a lower viability during most of the starvation period than cells starved in artificial sea water alone, while cells starved in the presence of arginine had a higher viability.Variations in the content of protein, carbon and nitrogen, in c.f.u. and in the uptake of arginine throughout a 30-day period indicate that A. denitrificans does not rapidly adapt to starvation but undergoes a series of cellular alterations.     

Paenibacillus marinisediminis sp. nov., a bacterium isolated from marine sediment

A Gram-negative, nonmotile, endospore-forming, rod-shaped bacterial strain LHW35^T, which belonged to the genus Paenibacillus, was isolated from marine sediment collected from the south coast of the Republic of Korea. A phylogenetic analysis of 16S rRNA gene sequences indicated that strain LHW35^T was most closely related to Paenibacillus taiwanensis G-soil-2-3^T (97.2% similarity). The optimal growth conditions for strain LHW35^T were 37°C, pH 6.0, and 0% (w/v) NaCl. The main isoprenoid quinone was menaquinone-7 (MK-7) and the major polyamine was spermidine. The diamino acid present in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major fatty acids were anteiso-C_15:0 and C_16:0. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, unidentified amino-hospholipids, unidentified phospholipids, and unidentified polar lipids. A DNA-DNA hybridization experiment using the type strain of P. taiwanensis indicated <40% relatedness. The DNA G+C content was 45.0 mol%. Based on these phylogenetic, genomic, and phenotypic analyses, strain LHW35^T should be classified as a novel species within the genus Paenibacillus, for which the name Paenibacillus marinisediminis sp. nov. is proposed. The type strain is LHW35^T (=KACC 16317^T =JCM 17886^T).     

A gas-producing marine bacterium

A gram-negative, aerogenic fermentative, marine bacterium is described and illustrated.     

A novel proteolytic activity in serum processes rat prohaptoglobin

The heterotetrameric plasma glycoprotein rat haptoglobin previously was shown to be synthesized by hepatocytes in a precursor form, prohaptoglobin, which contains one alpha-subunit region and one beta-subunit region. Two of these molecules, each with a molecular weight of 45,000, are joined by a disulfide bond and subsequently the subunit regions of each polypeptide are separated by site-specific proteolysis, yielding the tetrameric native protein. Although some of this processing occurs intracellularly, a substantial proportion of the prohaptoglobin is secreted [J. M. Hanley, T. H. Haugen, and E. C. Heath (1983) J. Biol. Chem. 258, 7858-7869]. However, a proteolytic activity was found in rat plasma and serum which also is capable of site-specific cleavage of prohaptoglobin. Further investigation of this novel activity has demonstrated that it cleaves prohaptoglobin accurately, in the same site-specific manner as the intracellular protease, and that it most likely is not a serine protease or a metalloenzyme but can be inhibited by sulfhydryl-reactive compounds. Furthermore, it appears to be synthesized and secreted by hepatocytes, and thus may be identical to the intracellular processing protease.