Genus Rheinheimera Research Articles

Differential Abundances of Bdellovibrio and Rheinheimera in the Oral Microbiota of Neonates With and Without Clinical Sepsis.

Neonatal sepsis is associated with high rates of morbidity and mortality, long hospital stays and high cost of care, thereby inflicting a burden on health care systems. Oral care with breast milk has been shown to modify the intestinal tract microbiota and immune system. Herein, we attempted to identify probiotics that may be beneficial to prevent or treat neonatal sepsis. This was a secondary analysis comparing the microbiota during oropharyngeal care in very-low-birth-weight infants with and without clinical sepsis. Oral samples were collected before oral feeding was initiated. The primary outcome was oral microbiota composition including diversity, relative abundance and linear discriminant analysis effect size. Sixty-three neonates, including 39 and 24 with and without clinical sepsis, respectively, were enrolled. The medians gestational age and birth weight were 29 (27-30) weeks and 1010 (808-1263) g. Neonates with clinical sepsis had lower gestational age, birth weight (both P < 0.001) and lower rate of oral care with breast milk ( P = 0.03), but higher doses and days of antibiotic exposure (both P < 0.001) compared to neonates without clinical sepsis. No differences in alpha and beta diversities were found between groups and Streptococcus agalactiae was the most common bacteria in both groups. Linear discriminant analysis effect size analysis revealed that neonates without clinical sepsis had significantly higher abundances of order Bdellovibrionales, family Bdellovibrionaceae, genus Bdellovibrio and genus Rheinheimera . Neonates without clinical sepsis had a significantly greater abundance of the Bdellovibrio and Rheinheimera genera.

Rheinheimera oceanensis sp. nov., a novel member of the genus Rheinheimera, isolated from the West Pacific Ocean.

Two Gram-stain-negative, aerobic, non-motile and short-rod-shaped bacteria, designated as strains GL-53T and GL-15-2-5, were isolated from the seamount area of the West Pacific Ocean and identified using a polyphasic taxonomic approach. The growth of strains GL-53ᵀ and GL-15-2-5 occurred at pH 5.5-10.0, 4-40 °C (optimum at 28 °C) and 0-10.0 % NaCl concentrations (optimum at 0-5.0 %). On the basis of 16S rRNA gene sequence analysis, strains GL-53ᵀ and GL-15-2-5 exhibited the highest similarity to Rheinheimera lutimaris YQF-2T (98.4 %), followed by Rheinheimera pacifica KMM 1406T (98.1 %), Rheinheimera nanhaiensis E407-8T (97.4 %), Rheinheimera aestuarii H29T (97.4 %), Rheinheimera hassiensis E48T (97.2 %) and Rheinheimera aquimaris SW-353T (97.2 %). Phylogenetic analysis revealed that the isolates were affiliated with the genus Rheinheimera and represented an independent lineage. The major fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The sole isoprenoid quinone was ubiquinone 8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid (and one unidentified glycolipid. The DNA G+C content was 48.5 mol%. The average nucleotide identity, average amino acid identity and in silico DNA-DNA hybridization values among the genomes of strain GL-53ᵀ and the related strains in the genus Rheinheimera were 75.5-90.1 %, 67.5-93.9 % and 21.4-41.4 %, respectively. Based on their phenotypic, chemotaxonomic and genotypic properties, the two strains were identified as representing a novel species of the genus Rheinheimera, for which the name Rheinheimera oceanensis sp. nov. is proposed. The type strain is GL-53T (=KCTC 82651T=MCCC M20598T).

Rheinheimera faecalis sp. nov., isolated from Ceratotherium simum feces

A novel strain YR1T, Gram-stain-negative, rod-shaped, catalase- and oxidase-positive, and aerobic bacterium, was isolated from the feces of Ceratotherium simum. The strain grew at 9-42°C (optimal temperature, 30°C), at pH 6.0-10.0 (optimal pH, 7.0), and in the presence of 0-3% (w/v) NaCl (optimal salinity, 0%). Phylogenetic analyses based on 16S rRNA gene sequencing indicated that strain YR1T was most closely related to Rheinheimera soli BD-d46T (98.6%), R. riviphila KYPC3T (98.6%), and R. mangrovi LHK 132T (98.1%). Moreover, the average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values between strain YR1T and R. mangrovi LHK 132T were 88.3%, 92.1%, and 35.3%, respectively, indicating that strain YR1T is a novel species in the genus Rheinheimera. The genome size and genomic DNA G + C content of strain YR1T were 4.5 Mbp and 46.37%, respectively. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol, while the predominant respiratory quinone was Q-8. Summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16: 0, and summed feature 8 (C18:1 ω7c) were the primary cellular fatty acids (> 16%). Based on these genotypic and phenotypic characteristics, strain YR1T was identified as a novel species in the genus Rheinheimera, for which the name Rheinheimera faecalis sp. nov. is proposed, with the type strain is YR1T (= KACC 22402T = JCM 34823T).

Mercury remediation potential of mercury-resistant strain Rheinheimera metallidurans sp. nov. isolated from a municipal waste dumping site

A novel mercury-resistant bacterium, designated strain DCL_24T, was isolated from the legacy waste at the Daddu Majra dumping site in Chandigarh, India. It showed resistance up to 300 µM of inorganic mercury (mercuric chloride). The isolate was found to be a Gram-negative, facultative anaerobic, motile, and rod-shaped bacterium that can grow at 4 – 30 °C (optimum 25 °C), pH 6.0 – 12.0 (optimum 7.0), and 0 – 4.0 % (w/v) NaCl (optimum 0.5 – 2.0 %). The 16 S rRNA gene-based phylogenetic analysis showed that DCL_ 24 T shared a 97.53 % similarity with itsºlosest type strain Rheinheimera muenzenbergensis E-49T. Insilico DNA-DNA hybridization and average nucleotide identity values were found to be 18.60 % and 73.77 %, respectively, between the genomes of DCL_24T and R. muenzenbergensis E-49T. The strain DCL_24T has 44.33 DNA G+C content (mol %). Based on the phenotypic, chemotaxonomic, and genotypic data, the strain DCL_24T represents a novel species within the genus Rheinheimera, for which the name Rheinheimera metallidurans sp. nov is proposed. The type strain is DCL_24T (MTCC13203T = NBRC115780T = JCM 35551 T). The isolate was found to volatilize and remove mercury efficiently, as demonstrated by X-ray film and dithizone-based colorimetric methods. Around 92 % of mercury removal was observed within 48 h. The mercury-resistant determinant mer operon consisting of merA, encoding the mercuric reductase enzyme, and transport and regulatory genes (merT, merP, merD, and merR) were found in the isolate. Relative expression analysis of merA at increasing concentrations of HgCl2 was confirmed by quantitative real-time PCR. These data indicate the merA-mediated reduction of toxic Hg2+ into a non-toxic volatile Hg0. The phytotoxicity assay performed using Arabidopsis thaliana seeds further demonstrated the mercury toxicity reduction potential of DCL_24T. The study shows that this novel isolate, DCL_24T, is an interesting candidate for mercury bioremediation. However, further studies are required to assess the bioremediation efficacy of the strain under the harsh environmental conditions prevailing in polluted sites.

Rheinheimera sediminis sp. nov., a marine bacterium isolated from coastal sediment.

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated strain YQF-1T, was isolated from coastal sediment in Jiangsu Province (PR China) and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 28 °C (range 4-40 °C) and pH 7 (range pH 6-11). Phylogenetic analysis based on 16S rRNA gene sequence indicated that YQF-1T was related to members of the genus Rheinheimera and shared the highest sequence identities with Rheinheimera mesophila DSM 29723T (98.5 %), followed by Rheinheimera tangshanensis DSM 19460T (98.4 %), Rheinheimera tilapiae Ruye-90T (97.9 %), Rheinheimera soli BD-d46T (97.9 %), Rheinheimera aquatica GR5T (97.4 %), Rheinheimera coerulea TAPG2T (97.3 %) and Rheinheimera texasensis A62-14BT (97.1 %). The 16S rRNA gene sequence identities between YQF-1T and other members of the genus Rheinheimera were below 97.0 %. The digital DNA-DNA hybridization value between YQF-1T and Rheinheimera mesophila DSM 29723T was 25.1±2.3 %. The average nucleotide identity (ANI) value between YQF-1T and Rheinheimera mesophila DSM 29723T was 81.4 %. The major respiratory quinone was Q-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, two unidentified aminolipids and three unidentified lipids. The strain had summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15 : 0, and anteiso-C17 : 1 ω9c as the major fatty acids. The G+C content of the genomic DNA was 46.2 mol%. On the basis of phenotypic, genotypic and phylogenetic evidence, strain YQF-1T represents a novel species of the genus Rheinheimera, for which the name Rheinheimera sediminis sp. nov. is proposed, with the type strain YQF-1T (=KCTC 72183T=MCCC 1K03646T).

Rheinheimera pleomorphica sp. nov., a Novel Alkali-Tolerant Bacteria Isolated from Chilika Lake, India.

A novel Gram-negative gamma-proteobacterium, non-sporulating motile, rod or coccus-shaped bacterium designated as strain PKS7T was isolated from a sediment sample collected from Chilika Lake, Odisha, India and characterized taxonomically using a polyphasic approach. The major quinone was Q8 and major cellular fatty acids were C16:0, C17:0, C15:1w8c, C17:1w8c, C12:03-OH. The chemotaxonomic features confirmed the isolate to be a member of genus Rheinheimera. 16SrRNA gene sequence of strain PKS7T was closest in similarity to R. aquimaris SW-353T (99.36% identity), R. muenzenbergensis E49T (98.63%), R. nanhaiensis E407-8T (98.35%), R. japonica KMM 9513T (98.35%) and R. baltica DSM-14885T (98.08%). The 16S rRNA gene sequence-based phylogenetic analysis and sequence similarity between the isolated strain and type strains also revealed its affiliation to genus Rheinheimera. DNA-DNA relatedness with closest type strain R. aquimaris SW-353T was 25.0% (±3.40) and in silico DDH showed values in the range of 17.7-37.1% with the type strains of the genus Rheinheimera for which whole genome sequence are available. Strain PKS7T was also distinguished by a multi-locus sequence analysis (MLST) by alingning gyrB gene sequences of the closest type strains of Rheinheimera. The draft genome of strain PKS7T contained 32 contigs of total size 3,963,569bp comprising of 3763 predicted coding sequences with a G + C content of 50.7mol%. Comparision of phenotypic and genotypic data with its closest neighbours and closely related species confirm the strain PKS7T to be recognised as a novel species within the genus Rheinheimera, for which the name Rheinheimera pleomorphica sp. nov. is proposed. The type strain is PKS7T (= KCTC 42365 = JCM 30460).

Rheinheimera riviphila sp. nov., isolated from a freshwater stream.

Strain KYPC3T, isolated from a freshwater stream in Taiwan, was characterized using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain KYPC3T belonged to the genus Rheinheimera. Strain KYPC3T exhibited 16S rRNA gene sequence similarity values of 94.8-97.9% to the type strains of species of the genus Rheinheimera. Strain KYPC3T was most closely related to Rheinheimera chironomi K19414T with 16S rRNA gene sequence similarity of 97.9%. Cells of strain KYPC3T were Gram-stain negative, aerobic, motile by means of a single-polar flagellum, non-spore forming, coccoid or short rods surrounded by a thick capsule and forming off-white coloured colonies. Growth occurred at 15-30°C (optimum, 20-25°C), at pH 6-8 (optimum, pH 7) and with 0-0.5% NaCl (optimum, 0%). The major fatty acids (> 10%) of strain KYPC3T were C12:0 3-OH, summed feature 3 (C16:1ω7c and/or C16:1ω6c) and C16:0. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, an uncharacterized aminophospholipid, an uncharacterized phospholipid and an uncharacterized lipid. The major isoprenoid quinone was Q-8. The draft genome was approximately 4.75Mb in size with a G + C content of 49.8mol%. The DNA-DNA relatedness of strain KYPC3T with respect to recognized species of the genus Rheinheimera was significantly less than 70%. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain KYPC3T should be classified as a novel species of the genus Rheinheimera, for which the name Rheinheimera riviphila sp. nov. is presented. The type strain is KYPC3T (= BCRC 81008T = LMG 29729T = KCTC 52440T).

Rheinheimera coerulea sp. nov., isolated from a freshwater creek, and emended description of genus Rheinheimera Brettar et al. 2002.

A bacterial strain designated TAPG2T was isolated from a freshwater creek in Taiwan and characterized using the polyphasic taxonomic approach. Cells of TAPG2T were Gram-stain negative, aerobic, motile, non-spore forming, short rods surrounded by a thick capsules and forming cream to dark-green colonies. Growth occurred at 15-37 °C (optimum, 25-30 °C), at pH 6.5-8 (optimum, pH 7) and with 0-1 % NaCl (optimum, 0.5 %). The major fatty acids (>10 %) of TAPG2T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, an uncharacterized aminophospholipid, an uncharacterized phospholipid, an uncharacterized aminolipid and an uncharacterized lipid. The polyamine profile was composed of the major compound putrescine and moderate amounts of spermidine. The only isoprenoid quinone was Q-8. The DNA G+C content was 53.6 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that TAPG2T represented a member of the genus Rheinheimera and was most closely related to Rheinheimera aquatica GR5T and Rheinheimera texasensis A62-14BT with 98.6 and 98.2 % 16S rRNA gene sequence identities, respectively. However, DNA-DNA hybridization values of TAPG2T with type strains of the species with validly published names were lower than 30 %. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that TAPG2T should be classified as representing a novel species of the genus Rheinheimera, for which the name Rheinheimera coerulea sp. nov. is presented. The type strain is TAPG2T (=BCRC 81054T=LMG 30056T=KCTC 52815T).

Rheinheimera marina sp. nov., isolated from a deep-sea seamount.

A bacterial strain designated TP462T, isolated from a seamount near the Yap Trench in the tropical western Pacific, was characterized using a polyphasic taxonomic approach. Strain TP462T was found to be Gram-stain-negative, aerobic, rod-shaped and motile by means of a single polar flagellum. Growth occurred at 4-37 °C (optimum, 25-30 °C) and with 0-4.0 % NaCl (optimum, 2-3 %). Phylogenetic analysis based on 16S rRNA gene sequence showed that strain TP462T was related to the genus Rheinheimera and had the highest 16S rRNA gene sequence similarity with the type strain Rheinheimera tangshanensis JA3-B52T (96.8 %). The predominant cellular fatty acids were C17 : 1ω8c, summed feature 3 (composed of iso-C15 : 0 2-OH and/or C16 : 1ω7c) and C16 : 0. The polar lipid profile contained phosphatidylglycerol, phosphatidylethanolamine and two unidentified lipids. The genomic DNA G+C content of strain TP462T was 48.7 mol%. On the basis of the evidence presented in this study, strain TP462T represents a novel species of the genus Rheinheimera, for which we propose the name Rheinheimera marina sp. nov. (type strain TP462T=KACC 18560T=CGMCC 1.15399T).

Rheinheimera salexigens sp. nov., isolated from a fishing hook, and emended description of the genus Rheinheimera.

A Gram-negative, rod-shaped bacterium, designated KH87T, was isolated from a fishing hook that had been baited and suspended in seawater off O'ahu, Hawai'i. Based on a comparison of 1524 nt of the 16S rRNA gene sequence of strain KH87T, its nearest neighbours were the GammaproteobacteriaRheinheimera nanhaiensis E407-8T (96.2 % identity), Rheinheimera chironomi K19414T (96.0 %), Rheinheimera pacifica KMM 1406T (95.8 %), Rheinheimera muenzenbergensis E49T (95.7 %), Alishewanella solinquinati KMK6T (94.9 %) and Arsukibacterium ikkense GCM72T (94.6 %). Cells of KH87T were motile by a single polar flagellum, strictly aerobic, and catalase- and oxidase-positive. Growth occurred between 4 and 39 °C, and in a circumneutral pH range. Major fatty acids in whole cells of strain KH87T were cis-9-hexadecenoic acid, hexadecanoic acid and cis-11-octadecenoic acid. The quinone system contained mostly menaquinone MK-7, and a minor amount of ubiquinone Q-8. The polar lipid profile contained the major lipids phosphatidylglycerol, phosphatidylserine, phosphatidylethanolamine, an unidentified aminolipid, and a lipid not containing phosphate, an amino group or a sugar moiety. Putrescine was the major polyamine. Physiological, biochemical and genomic data, including obligate halophily, absence of amylolytic activity, a quinone system dominated by MK-7 and DNA G+C content (42.0 mol%) distinguished KH87T from extant Rheinheimera species; strain KH87T was also distinguished by a multi-locus sequence analysis of aligned and concatenated 16S rRNA, gyrB, rpoB and rpoD gene sequences. Based on phenotypic and genotypic differences, the species Rheinheimera salexigens sp. nov. is proposed to accommodate KH87T as the type strain (=ATCC BAA-2715T=CIP 111115T). An emended description of the genus Rheinheimera is also proposed.

Emended description of the family Chromatiaceae, phylogenetic analyses of the genera Alishewanella, Rheinheimera and Arsukibacterium, transfer of Rheinheimera longhuensis LH2-2T to the genus Alishewanella and description of Alishewanella alkalitolerans sp. nov. from Lonar Lake, India.

Phylogenetic analyses were performed for members of the family Chromatiaceae, signature nucleotides deduced and the genus Alishewanella transferred to Chromatiaceae. Phylogenetic analyses were executed for the genera Alishewanella, Arsukibacterium and Rheinheimera and the genus Rheinheimera is proposed to be split, with the creation of the Pararheinheimera gen. nov. Furthermore, the species Rheinheimera longhuensis, is transferred to the genus Alishewanella as Alishewanella longhuensis comb. nov. Besides, the genera Alishewanella and Rheinheimera are also emended. Strain LNK-7.1T was isolated from a water sample from the Lonar Lake, India. Cells were Gram-negative, motile rods, positive for catalase, oxidase, phosphatase, contained C16:0, C17:1ω8c, summed feature3 (C16:1ω6c and/or C16:1ω7c) and summed feature 8 (C18:1ω7c) as major fatty acids, PE and PG as the major lipids and Q-8 as the sole respiratory quinone. Phylogenetic analyses using NJ, ME, ML and Maximum parsimony, based on 16S rRNA gene sequences, identified Alishewanella tabrizica RCRI4T as the closely related species of strain LNK-7.1T with a 16S rRNA gene sequence similarity of 98.13%. The DNA-DNA similarity between LNK-7.1T and the closely related species (A. tabrizica) was only 12.0% and, therefore, strain LNK-7.1T was identified as a novel species of the genus Alishewanella with the proposed name Alishewanella alkalitolerans sp. nov. In addition phenotypic characteristics confirmed the species status to strain LNK-7.1T. The type strain of A. alkalitolerans is LNK-7.1T (LMG 29592T=KCTC 52279T), isolated from a water sample collected from the Lonar lake, India.

Antibacterial low-molecular-weight compounds produced by the marine bacterium Rheinheimera japonica KMM 9513T.

Strain KMM 9513T was isolated from a sediment sample collected from the Sea of Japan seashore and selected due to its ability to inhibit indicator bacterial growth. The strain KMM 9513T has been recently described as a novel species Rheinheimera japonica. This study was undertaken to determine which substances produced by strain KMM 9513T could be responsible for its antimicrobial activity. Eight compounds were obtained from an ethyl acetate extract of R. japonica KMM 9513T. The structures of five diketopiperazines (4-8) and diisobutyl-, dibutyl- and bis(2-ethylhexyl) phthalates (1-3) were established on the basis of detailed interpretation of NMR data, by Marfey method and optical rotation data. The structures of diketopiperazines were determined as cyclo-(L-valyl-L-proline), cyclo-(L-valyl-D-proline), cyclo-(L-phenylalanyl-L-proline), cyclo-(L-leucyl-L-proline), and cyclo-(L-phenylalanyl-D-proline). Compounds 1-3, 5 and 8 revealed antimicrobial activities against Bacillus subtilis and/or Enterococcus faecium and Staphylococcus aureus. In this paper, we describe the isolation and structural elucidation of the isolated compounds 1-8. This is the first report of the characterisation of low molecular weight antibacterial metabolites produced by a member of the genus Rheinheimera.

Microbiological mechanism of the improved nitrogen and phosphorus removal by embedding microbial fuel cell in Anaerobic–Anoxic–Oxic wastewater treatment process

Anaerobic–Anoxic–Oxic (AA/O) wastewater treatment process is a widely used wastewater treatment process for simultaneous nitrogen and phosphorus removal. Microbial fuel cell (MFC) can generate electricity and treat the organic wastewater simultaneously. Our previous research showed that embedding MFC in AA/O wastewater treatment process could enhance the pollutants removal efficiency. However, the mechanism was not clear. In this study, a lab-scale corridor-style AA/O reactor with MFC embedded was operated and both the total nitrogen and total phosphorus removal efficiencies were enhanced. DGGE and Illumina Miseq results demonstrated that both the microbial community structures on the surface of the cathode and in the suspensions of cathode chamber have been changed. The percentage of Thauera and Emticicia, identified as denitrifying bacteria, increased significantly in the suspension liquid when the MFC was embedded in the AA/O reactor. Moreover, the genus Rheinheimera were significantly enriched on the cathode surface, which might contribute to both the nitrogen removal enhancement and electricity generation.

Rheinheimera gaetbuli sp. nov., a Marine Bacterium Isolated from a Tidal Flat.

A gram-staining-negative, strictly aerobic, rod-shaped, and motile bacterium with a single polar flagellum, designated H26(T), was isolated from tidal flat sediment in Jeju Island, South Korea. Growth of strain H26(T) was observed at 4-35 °C (optimum, 20-25 °C), pH 6.0-9.0 (optimum, pH 7.0-8.0), and 1-4 % NaCl (optimum, 2-3 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain H26(T) formed a phyletic lineage within the genus Rheinheimera, family Chromatiaceae. Strain H26(T) was most closely related to Rheinheimera baltica OSBAC1(T), Rheinheimera aestuarii H29(T), Rheinheimera muenzenbergensis E49(T), and Rheinheimera aquimaris SW-353(T) with 98.5, 98.1, 97.8, and 97.5 % of 16S rRNA gene sequence similarities, respectively. The DNA-DNA relatedness levels between strain H26(T) and the type strains of R. baltica, R. aestuarii, R. muenzenbergensis, and R. aquimaris were 35.5 ± 3.2, 33.4 ± 1.5, 31.2 ± 2.2, and 28.7 ± 0.9 %, respectively. The major fatty acids of strain H26(T) were iso-C15:0 3-OH, summed feature 3 (comprising C16:1 ω7c/C16:1 ω6c), C16:0, summed feature 8 (comprising C18:1 ω7c/C18:1 ω6c), iso-C17:0 3-OH, and C12:0 3-OH and the strain contained ubiquinone (Q-8) as the sole isoprenoid quinone. Phosphatidylethanolamine, phosphatidylglycerol, and an aminolipid were identified as the major polar lipids and the G + C content of the genomic DNA was 52.0 mol%. Based on the phenotypic, chemotaxonomic, and molecular properties, strain H26(T) represents a novel species of the genus Rheinheimera, for which the name Rheinheimera gaetbuli sp. nov. is proposed. The type strain was H26(T) (=KACC 18254(T) = JCM 30403(T)).

Rheinheimera aestuari sp. nov., a marine bacterium isolated from coastal sediment.

A Gram-stain-negative, strictly aerobic, non-pigmented, motile bacterium with a single polar flagellum, designated H29T, was isolated from coastal sediment of Jeju Island, South Korea. Cells were non-spore-forming rods showing catalase- and oxidase-positive reactions. Growth of strain H29T was observed at 10-40 °C (optimum, 20-25 °C) and pH 6.0-9.0 (optimum, pH 7.0-8.0), and in the presence of 1-4% (w/v) NaCl (optimum, 2-3%). Strain H29T contained C16 : 0, iso-C15 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) as the major fatty acids and ubiquinone-8 (Q-8) as the sole isoprenoid quinone. Phosphatidylethanolamine and phosphatidylglycerol were identified as the major polar lipids. The G+C content of the genomic DNA was 46.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain H29T formed a phyletic lineage with Rheinheimera hassiensis E48T within the genus Rheinheimera of the family Chromatiaceae. Strain H29T was most closely related to Rheinheimera pacifica KMM 1406T, Rheinheimera muenzenbergensis E49T, Rheinheimera hassiensis E48T and Rheinheimera baltica OSBAC1T with 97.8%, 97.6%, 97.4% and 97.2% 16S rRNA gene sequence similarities, respectively. However, DNA-DNA hybridization values of strain H29T with type strains of these species were lower than 70%. On the basis of the phenotypic, chemotaxonomic and molecular properties, strain H29T represents a novel species of the genus Rheinheimera, for which the name Rheinheimeraaestuarii sp. nov. is proposed. The type strain is H29T ( = KACC 18251T = JCM 30404T).

Taxonomic description and genome sequence of Rheinheimera mesophila sp. nov., isolated from an industrial waste site.

A novel Gram-staining-negative gammaproteobacterium, designated IITR-13T, was isolated from a pesticide-contaminated soil and characterized using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, the strain showed the closest similarity (98.7 %) to Rheinheimera tangshanensis JA3-B52T followed by Rheinheimera texasensis A62-14BT (97.7 %) and Rheinheimera soli BD-d46T (97.3 %). The 16S rRNA gene sequence similarity of the novel strain to other members of the genus Rheinheimera was < 97.3 %. However, DNA-DNA hybridization between strain IITR-13T and the type strains of R. tangshanensis, R. texasensis and R. soli was 47.5 ± 0.6, 42.4 ± 0.4 and 39.8 ± 0.3 %, respectively; these values are less than 70 %, a threshold value for delineation of a novel species. The strain had C12 : 0 3-OH, C16 : 0, C17 : 1ω8c, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c) and C18 : 1ω6c as the major fatty acids. The major isoprenoid quinones detected for strain IITR-13T were ubiquinone Q-8 and menaquinone MK-7.The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and seven unknown phospholipids. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the novel strain should be assigned to a novel species, for which the name Rheinheimera mesophila sp. nov. is proposed, with the type strain IITR-13T ( = MTCC 12064T = DSM 29723T). Also, we report the draft genome sequence of Rheinheimera mesophila IITR-13T; the draft genome sequence includes 3 749 903 bases and comprises 3449 predicted coding sequences, with a G+C content of 47.8 %. It consists of 102 contigs (>1000 bp).

Rheinheimera japonica sp. nov., a novel bacterium with antimicrobial activity from seashore sediments of the Sea of Japan.

Two gram-negative, aerobic, brown-pigmented, motile rod-shaped bacteria KMM 9512 and KMM 9513(T) were isolated from a sediment sample collected from the Sea of Japan seashore, Russia. On the basis of the 16S rRNA gene sequence analysis, novel strains KMM 9512 and KMM 9513(T) positioned within the genus Rheinheimera (class Gammaproteobacteria) as a separate subline adjacent to Rheinheimera baltica DSM 14885(T) sharing highest gene sequence similarities of 98.6-97.6 % to their closest phylogenetic relatives, Rheinheimera muenzenbergensis LMG 27269(T), R. baltica DSM 14885(T), Rheinheimera aquimaris JCM 14331(T), Rheinheimera nanhaiensis KACC 14030(T), and Rheinheimera pacifica KMM 1406(T). Strains KMM 9512 and KMM 9513(T) belong to the same separate genospecies on the basis of the 16S rRNA gene sequence similarity (99.8 %) and their DNA relatedness to each other (89 %) and to closely related Rheinheimera species (25-53 %). The major isoprenoid quinone was Q-8, polar lipids consisted of phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine, unknown aminolipids, unknown aminophospholipids, unknown phospholipids, and unknown lipids, and major fatty acid were C16:0, C16:1 ω7c, C17:1 ω8c, C12:0 3-OH followed by C17:0 and C18:1 ω7c in both strains. Strains KMM 9512 and KMM 9513(T) revealed a remarkable antagonistic activity toward a number of gram-positive and gram-negative microorganisms. On the basis of phylogenetic analysis, DNA-DNA hybridization results, and phenotypic differences, strains KMM 9512 and KMM 9513(T) are proposed to be classified as a novel species of the genus Rheinheimera, Rheinheimera japonica sp. nov. The type strain of this species is KMM 9513(T) = NRIC 0918(T).

A New Esterase, Belonging to Hormone-Sensitive Lipase Family, Cloned from Rheinheimera sp. Isolated from Industrial Effluent

The gene for esterase (rEst1) was isolated from a new species of genus Rheinheimera by functional screening of E. coli cells transformed with the pSMART/HaeIII genomic library. E. coli cells harboring the esterase gene insert could grow and produce clear halo zones on tributyrin agar. The rEst1 ORF consisted of 1,029 bp, corresponding to 342 amino acid residues with a molecular mass of 37 kDa. The signal P program 3.0 revealed the presence of a signal peptide of 25 amino acids. Esterase activity, however, was associated with a homotrimeric form of molecular mass 95 kDa and not with the monomeric form. The deduced amino acid sequence showed only 54% sequence identity with the closest lipase from Cellvibrio japonicus strain Ueda 107. Conserved domain search and multiple sequence alignment revealed the presence of an esterase/ lipase conserved domain consisting of a GXSXG motif, HGGG motif (oxyanion hole) and HGF motif, typical of the class IV hormone sensitive lipase family. On the basis of the sequence comparison with known esterases/ lipases, REst1 represents a new esterase belonging to class IV family. The purified enzyme worked optimally at 50 degrees C and pH 8, utilized pNP esters of short chain lengths, and showed best catalytic activity with p-nitrophenyl butyrate (C₄), indicating that it was an esterase. The enzyme was completely inhibited by PMSF and DEPC and showed moderate organotolerance.

Rheinheimera aquatica sp. nov., Antimicrobial Activity-Producing Bacterium Isolated from Freshwater Culture Pond

A bacterial strain designated GR5(T) was isolated from freshwater culture pond in Taiwan during the screening of bacteria for antimicrobial compounds and characterized using the polyphasic taxonomic approach. Strain GR5(T) was Gram-negative, aerobic, greenish-yellow colored, rod-shaped, and motile by means of a polar single flagellum. Growth occurred at 10-40 degrees C (optimum, 35 degrees C), at pH 7.0-8.0 (optimum pH 8.0) and with 0-2.0% NaCl (optimum, 0.5-1.0%). The major fatty acids were C(16:1) omega7c (36.3%), C(16:0) (16.6%), C(12:0) 3-OH (12.5%) and C(18:1) omega7c (9.1%). The major respiratory quinone was Q-8. The DNA G+C content of the genomic DNA was 51.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GR5(T) belonged to the genus Rheinheimera and its most closely neighbours were Rheinheimera texasensis A62-14B(T) and Rheinheimera tangshanensis JA3-B52(T) with sequence similarities of 98.1 and 97.5%, respectively. The sequence similarities to any other recognized species within Gammaproteobacteria were less than 96.5%. The mean level of DNA-DNA relatedness between strain GR5(T) and R. texasensis A62-14B(T), the strain most closely related to the isolate, was 26.5 +/- 7.6 %. On the basis of the phylogenetic and phenotypic data, strain GR5(T) should be classified as representing a novel species, for which the name Rheinheimera aquatica sp. nov. is proposed. The type strain is GR5(T) (= BCRC 80081(T) = LMG 25379(T)).

Rheinheimera nanhaiensis sp. nov., isolated from marine sediments, and emended description of the genus Rheinheimera Brettar et al. 2002 emend. Merchant et al. 2007

A Gram-negative, facultatively aerobic, oxidase- and catalase-positive, rod-shaped bacterium, designated strain E407-8(T), was isolated from a sediment sample from the South China Sea. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain E407-8(T) was affiliated with the genus Rheinheimera, sharing the highest sequence similarity with Rheinheimera pacifica KMM 1406(T) (97.5 %) and Rheinheimera aquimaris SW-353(T) (97.4 %) and showing less than 97 % sequence similarity to the type strains of other recognized Rheinheimera species. Levels of DNA-DNA relatedness of strain E407-8(T) to R. pacifica DSM 17616(T) and R. aquimaris JCM 14331(T) were 25.2 % (25.3 % in the duplicate measurement) and 9.4 % (6.5 %), respectively. The bacterium could grow at 10-48 °C (optimum 37 °C) and in the presence of 0-8 % (w/v) NaCl (optimum 0.5-2.5 %). The major cellular fatty acids of strain E407-8(T) were summed feature 3 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), C(17 : 1)ω8c, C(16 : 0) and C(18 : 1)ω7c. The predominant respiratory quinone was ubiquinone Q-8. The DNA G+C content was 51.0 mol%. Based on the results of our polyphasic taxonomic study, strain E407-8(T) represents a novel species in the genus Rheinheimera, for which the name Rheinheimera nanhaiensis sp. nov. is proposed. The type strain is E407-8(T) ( = CCTCC AB 209089(T) = KACC 14030(T)). An emended description of the genus Rheinheimera Brettar et al. 2002 emend. Merchant et al. 2007 is also proposed.