Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov., isolated from surface seawater of the Pacific Ocean

Two Gram-negative, non-spore-forming, non-motile, non-flagellated bacteria, designated strains D6T and DH64T, were isolated from surface water of the Pacific Ocean. For strain D6T, growth occurred at 10-40 °C, pH 5.5-9.0 and in the presence of 0-8.0 % NaCl (w/v). For strain DH64T, growth occurred at 10-40 °C, pH 5.5-8.5 and in the presence of 0.5-8.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains D6T and DH64T both belonged to the genera Flagellimonas, with the highest sequence identities to Flagellimonas taeanensis JCM 17757T (98.2 %) and Flagellimonas marinaquae JCM 11811T (98.6 %), respectively. The 16S rRNA gene sequence identity between strains D6T and DH64T was 95.9 %. The average amino acid identity and digital DNA-DNA hybridization values between the two strains and the nearest phylogenetic neighbours were 66.7-93.3 % and 16.1-38.5 %, respectively. The major respiratory quinone of both strains was menaquinone-6. The major polar lipid was phosphatidylethanolamine. The major fatty acids were identified similarly as iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. The genomic G+C contents of strains D6T and DH64T were determined to be 45.5 and 42.6 mol%, respectively. The combined genotypic and phenotypic data show that the strains represent two novel species within genera Flagellimonas, for which the names Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov. are proposed, with type strains D6T (=MCCC M28982T=KCTC 92604T) and DH64T (=MCCC M28986T=KCTC 92975T).

Reclassification of Allomuricauda and Muricauda species as members of the genus Flagellimonas Bae et al. 2007 and emended description of the genus Flagellimonas

The recently proposed genus Allomuricauda Deshmukh and Oren 2023 is illegitimate because it includes the type species of the genera Flagellimonas Bae et al. 2007 and Spongiibacterium Yoon and Oh 2012, contravening Rule 51b(1) of the International Code of Nomenclature of Prokaryotes. As Flagellimonas Bae et al. 2007 is the earlier described genus, we here reclassify 36 species earlier described as belonging to the illegitimate genus Muricauda as species of Flagellimonas. We also present an emended description of the genus Flagellimonas.

Proposal of Allomuricauda gen. nov. and Allofranklinella gen. nov. as replacement names for the illegitimate prokaryotic generic names Muricauda and Franklinella, respectively

The prokaryotic generic names Muricauda Bruns et al. 2001 and Franklinella Bernard et al. 2022 are illegitimate because they are later homonyms of the genus names Muricauda Small 1903 (synonym of Arisaema; Tracheophyta - Liliopsida - Araceae) and Franklinella Stewart and Hendrix 1945 (a Devonian ostracod genus) and Franklinella Lenz 1973 (a Devonian brachiopod genus), respectively (Principle 2 and Rule 51b(4) of the International Code of Nomenclature of Prokaryotes). We therefore propose the replacement generic names Allomuricauda and Allofranklinella, with type species Allomuricauda ruestringensis and Allofrankinella schreckenbergeri, respectively.

Muricauda okinawensis sp. Nov. and Muricauda yonaguniensis sp. Nov., Two Marine Bacteria Isolated from the Sediment Core near Hydrothermal Fields of Southern Okinawa Trough

Two strains, 81s02^T and 334s03^T, were isolated from the sediment core near the hydrothermal field of southern Okinawa Trough. The cells of both strains were observed to be rod-shaped, non-gliding, Gram-staining negative, yellow-pigmented, facultatively anaerobic, catalase and oxidase positive, and showing optimum growth at 30 °C and pH 7.5. The strains 81s02^T and 334s03^T were able to tolerate up to 10% and 9% (w/v) NaCl concentration, respectively. Based on phylogenomic analysis, the average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) values between the two strains and the nearest phylogenetic neighbors of the genus Muricauda were in range of 78.0-86.3% and 21.5-33.9%, respectively. The strains 81s02^T and 334s03^T shared 98.1% 16S rRNA gene sequence similarity to each other but were identified as two distinct species based on 81.4-81.5% ANIb, 85.5-85.6% ANIm and 25.4% dDDH values calculated using whole genome sequences. The strains 81s02^T and 334s03^T shared the highest 16S rRNA gene sequence similarity to M. lutimaris SMK-108^T (98.7%) and M. aurea BC31-1-A7^T (98.8%), respectively. The major fatty acid of strains 81s02^T and 334s03^T were identified similarly as iso-C_15:0, iso-C_17:0 3-OH and iso-C_15:1 G, and the major polar lipids of the both strains consisted of phosphatidylethanolamine and two unidentified lipids. The strains contained MK-6 as their predominant menaquinone. The genomic G+C contents of strains 81s02^T and 334s03^T were determined to be 41.6 and 41.9 mol%, respectively. Based on the phylogenetic and phenotypic characteristics, both strains are considered to represent two novel species of the genus Muricauda, and the names Muricauda okinawensis sp. nov. and Muricauda yonaguniensis sp. nov. are proposed for strains 81s02^T (=KCTC 92889^T = MCCC 1K08502^T) and 334s03^T (=KCTC 92890^T = MCCC 1K08503^T).

Muricauda abyssi sp. nov., a marine bacterium isolated from deep seawater of the Mariana Trench

A Gram-stain-negative, non-motile and rod-shaped bacterium, designated as strain W52^T, was isolated from deep seawater of the Mariana Trench and characterized phylogenetically and phenotypically. The strain could grow at 10-47 °C (optimum 32 °C), at pH 5.0-8.0 (optimum 6.0) and with 0-9% NaCl (optimum 3 %, w/v). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that W52^T was related to members of the genus Muricauda and shared the highest identity with Muricauda oceani 501str8^T (99.0 %), followed by Muricauda aquimarina JCM 11811^T, Muricauda ruestringensis DSM 13258^T, Muricauda oceanensis 40DY170^T, Muricauda beolgyonensis KCTC 23501^T and Muricauda zhangzhouensis 12C25^T with 97.0-98.8 % sequence similarity. 16S rRNA gene sequence identities between W52^T and other members of the genus Muricauda were below 97.0 %. The major respiratory quinone was MK-6. The polar lipids were phosphatidylethanolamine (PE), one unidentified aminolipid and three unidentified lipids. The strain had iso-C_15 : 0, iso-C_17 : 0 3-OH and iso-C_15 : 1G as the major fatty acids. The G+C content of the genomic DNA was 41.7 %. The combined genotypic and phenotypic data indicated that strain W52^T represents a novel species of the genus Muricauda, for which the name Muricauda abyssi sp. nov. is proposed, with the type strain W52^T (=MCCC 1K05111^T= KCTC 82315^T).

Muricauda onchidii sp. nov., isolated from a marine invertebrate from South China Sea, and transfers of Flagellimonas algicola, Flagellimonas pacifica and Flagellimonas maritima to Muricauda algicola comb. nov., Muricauda parva nom. nov. and Muricauda aurantiaca nom. nov., respectively, and emended description of the genus Muricauda

An aerobic, Gram-stain-negative, rod-shaped and non-motile strain (XY-359^T) was isolated from the mouth of a marine invertebrate Onchidium species from the South China Sea. It grew at pH 6.0-8.5 (optimum, pH 7.5), at 15-37 °C (optimum, 30 °C) and in the presence of 0.5-4.5 % (w/v) NaCl (optimum, 2.5 %). It could not hydrolyse Tweens 20, 40, 60 or 80 and no flexirubin-type pigments were produced. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, six unidentified phospholipids and two unidentified polar lipids. The major fatty acids were iso-C_17:0 3-OH, iso-C_15:1 G and iso-C_15:0 3-OH. The respiratory quinone was MK-6. Strain XY-359^T showed the greatest degree of 16S rRNA sequence similarity to Flagellimonas algicola AsT0115^T (96.54 %), followed by Muricauda flava DSM 22638^T (96.27 %). Phylogenetic analysis based on 16S rRNA gene sequences and 31 core genes indicated that strain XY-359^T belongs to the genus Muricauda. The genome size of strain XY-359^T was 4 207 872 bp, with 39.1 mol% of DNA G+C content. The average nucleotide identity and digital DNA-DNA hybridization values between strain XY-359^T and F. algicola AsT0115^T were 74.58 % and 18.5 %, respectively, and those between strain XY-359^T and M. flava DSM 22638^T were 74.2 % and 18.3 %. The combined phenotypic, chemotaxonomic and phylogenetic data suggest that strain XY-359^T represents a novel species of the genus Muricauda, for which the name Muricauda onchidii sp. nov. is proposed. The type strain is XY-359^T (=MCCC 1K03658^T =KCTC 72218^T). Moreover, based on the proposal of nesting Spongiibacterium and Flagellimonas within Muricauda by García (Validation List No. 193) and the analyses of phylogenetic trees and average amino acid identities in this study, the transfers of F. algicola, F. pacifica and F. maritima to the genus Muricauda as Muricauda algicola comb. nov., Muricauda parva nom. nov. and M. aurantiaca nom. nov., respectively, are proposed, with an emended description of the genus Muricauda.

Muricauda amphidinii sp. nov., a novel marine bacterium isolated from the phycosphere of dinoflagellate Amphidinium carterae

A Gram-stain-negative, aerobic, rod-shaped and non-motile bacterium was isolated from a liquid culture of dinoflagellate Amphidinium carterae and further designated as LMIT004^T. Optimal growth was observed at 25 °C, pH 7.0 and in the presence of 2 % (w/v) NaCl. Oxidase and catalase were positive. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LMIT004^T showed high similarities to type strains Muricauda nanhaiensis SM17004^T (96.77 %) and Muricauda aquimarina JCM11811^T (95.60 %) but formed a separate branch in the genus Muricauda. The G+C content of strain LMIT004^T was 39.0 mol%. The dominant fatty acids were iso-C_15 : 0 and iso-C_15 : 1 G. The polar lipids mainly contained phosphatidylethanolamine, five unidentified phospholipids and five unidentified polar lipids. The sole respiratory quinone was menaquinone-6 (MK-6). The draft genome of the type strain was 3.88 Mbp. The average nucleotide identity values between strain LMIT004^T and the two reference strains M. nanhaiensis SM17004^T and M. aquimarina JCM11811^T were 77.47 and 73.49 %, respectively. Based on the polyphasic analysis, strain LMIT004^T is suggested to represent a novel specie in the genus of Muricauda, for which the name Muricauda amphidinii sp. nov. is proposed. The type strain is LMIT004^T (=CICC 24871^T=KCTC 72948^T).

Muricauda sediminis sp. nov., isolated from western Pacific Ocean sediment

A Gram-stain-negative bacterium, designated strain 40Bstr401^T, was isolated from a sediment sample collected from the western Pacific Ocean. Analysis of its 16S rRNA gene sequence revealed that strain 40Bstr401^T belongs to the genus Muricauda and is closely related to type strains Muricauda antarctica Ar-22^T (98.2 %), Muricauda taeanensis 105^T (98.2 %) and Muricauda beolgyonensis BB-My12^T (97.4 %). The average nucleotide identity values for 40Bstr401^T with M. antarctica Ar-22^T and M. taeanensis 105^T are 79.3 % and 78.8 %, respectively. The in silico DNA-DNA hybridization values between strain 40Bstr401^T and M. antarctica Ar-22^T and M. taeanensis 105^T are 26.7 and 26.6 %, respectively. The major isoprenoid quinone of 40Bstr401^T is MK-6, and iso-C_17 : 0 3-OH and iso-C_15 : 0 are the dominant cellular fatty acids. The major polar lipids are phosphatidylethanolamine, four unidentified amino lipids and two unidentified lipids. The G+C content of the genomic DNA is 42.9 mol%. Its phylogenetic distinctiveness and chemotaxonomic differences, together with the phenotypic properties observed in this study, indicate that strain 40Bstr401^T can be differentiated from closely related species. Therefore, we propose strain 40Bstr401^T represents a novel species in the genus Muricauda, for which the name Muricauda sediminis sp. nov. is suggested. The type strain is 40Bstr401^T (=MCCC 1K04568^T=KCTC 82139^T).

Muricauda maritima sp. nov., Muricauda aequoris sp. nov. and Muricauda oceanensis sp. nov., three marine bacteria isolated from seawater

Three Gram-stain-negative, non-motile, rod-shaped strains, designated 72T, NH166T and 40DY170T, were isolated from seawater samples of the West Pacific Ocean, South China Sea and West Pacific Ocean, respectively. The 16S rRNA gene sequence similarity results revealed that strains 72Tand NH166T were most closely related to Muricauda antarctica Ar-22T, Muricauda taeanensis JCM 17757T, Muricauda beolgyonensis KCTC 23501T, Muricauda lutimaris KCTC 22173T and Muricauda hadalis MT-229T with 97.2–98.0% sequence similarity. 16S rRNA gene sequence analysis also indicated that strain 40DY170T was most closely related to Muricauda ruestringensis DSM 13258T, Muricauda aquimarina JCM 11811T, Muricauda lutimaris KCTC 22173T and Muricauda oceani 501str8T with 97.6–98.1% sequence similarity. The 16S rRNA gene sequence similarity values among strains 72T, NH166T and 40DY170T were 96.5–99.2%. Phylogenetic analyses indicated that three new isolates represented three novel species by forming two distinctive lineages within the genus Muricauda . The DNA G+C contents of strain 72T, NH166T and 40DY170T were 43.4, 43.4 and 42.4 mol%, respectively. The average nucleotide identity and in silico DNA–DNA hybridization values between strains 72T, NH166T, 40DY170T and the reference strains were 76.5–93.5% and 19.2–53.5%, respectively. The sole respiratory quinone in all strains was menaquinone-6. Their major fatty acids were iso-C17:0 3-OH, iso-C15:0 and iso-C15 : 1 G. The major polar lipids of strains 72T and NH166T were phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The major polar lipids of strain 40DY170T were phosphatidylglycerol, one unidentified phospholipid, one unidentified aminolipid and two unidentified lipids. On the basis of their distinct taxonomic characteristics, the three isolates represent three novel species of the genus Muricauda , for which the names Muricauda maritima sp. nov. (type strain 72T=KCTC 62229T=MCCC 1K03350T), Muricauda aequoris sp. nov. (NH166T=KCTC 62228T=MCCC 1K03449T) and Muricauda oceanensis sp. nov. (40DY170T=KCTC 72200T=MCCC 1K03569T) are proposed.

Muricauda brasiliensis sp. nov., isolated from a mat-forming cyanobacterial culture

Strain K001 was isolated from a cyanobacterial culture derived from Abrolhos, a reef bank microbial mat (South Atlantic Ocean-Brazil). Cells of K001 are Gram stain-negative, catalase and oxidase-positive, non-motile, rod-shaped, and with or without appendages. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain K001 belongs to the genus Muricauda. The highest strain K001 16S rRNA gene identity, ANI, and dDDH, respectively, are with M. aquimarina (98.90%, 79.23, 21.60%), M. ruestringensis (98.20%, 80.82, 23.40%), and M. lutimaris (97.86%, 79.23, 22.70%). The strain grows at 15-37 °C and between 0.5 and 10% NaCl. The major fatty acids of strain K001 are iso-C_15:0, iso-C_15:1 G, iso-C_17:0 3-OH, and summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c). The polar lipids are represented by phosphatidylethanolamine, three unidentified aminolipids, and three unidentified polar lipids. The major respiratory quinone is MK-6. The G+C content of the DNA of strain K001 is 41.62 mol%. Based on polyphasic analysis of strain K001, it was identified as a novel representative of the genus Muricauda and was named Muricauda brasiliensis sp. nov. The type strain is K001 (=CBMAI 2315^T = CBAS 752^T).

Muricauda ochracea sp. nov., isolated from a tidal flat in the Republic of Korea

A yellowish-brown-coloured bacterium, designated strain JGD-17T, was isolated from a tidal flat of Janggu-do, Garorim bay, Taean-gun, Chungcheongbuk-do, Republic of Korea. Cells were Gram-stain-negative, aerobic, non-flagellated and long-rod-shaped. Growth was observed at 20–45 °C (optimum, 25–30 °C), at pH 6.0–10.0 (9.0) and with 1–5 % (w/v) NaCl (1–3 %). Results of 16S rRNA gene sequence analysis indicated that strain JGD-17T was closely related to Muricauda nanhaiensis SM1704T (96.1 %), Muricauda olearia CL-SS4T (95.0 %), Muricauda beolgyonensis BB-My12T (94.9 %), Muricauda marina H19-56T (94.7 %) and Muricauda indica 3PC125-7T (94.5 %). The ranges of values for the average nucleotide identity and digital DNA–DNA hybridization analyses with related strains were 71.3–74.1 % and 16.9–18.2 %. The genomic DNA G+C content was 41.1 mol%. Phylogenetic analysis using the neighbour-joining method showed that strain JGD-17T formed a clade with Muricauda nanhaiensis SM1704T, Muricauda lutaonensis CC-HSB-11T, Muricauda lutea CSW06T and Muricauda pacifica SM027T. The major fatty acids were iso-C15 : 0 (26.9 %), iso-C15 : 1 G (19.5 %) and iso-C17 : 0 3-OH (12.7 %). The predominant respiratory quinone was menaquinone-6. The polar lipids were phosphatidylethanolamine, an unidentified aminolipid, an unidentified phospholipid and two unidentified lipids. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain JGD-17T represents a novel species within the genus Muricauda , for which the name Muricauda ochracea sp. nov. is proposed. The type strain is JGD-17T (=KCTC 72732T=KACC 21486T=JCM 33817T).

Muricauda hadalis sp. nov., a novel piezophile isolated from hadopelagic water of the Mariana Trench and reclassification of Muricauda antarctica as a later heterotypic synonym of Muricauda teanensis

A novel marine Gram-stain-negative, non-motile, aerobic and rod-shaped bacterium, designated as strain MT-229T, was isolated from the deep seawater in the Mariana Trench and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 30 °C (ranging 10–40 °C), pH 6 (ranging 3–11) and with 11 % (w/v) NaCl (ranging 0–17 %). Strain MT-229T was a piezophile, growing optimally at 20 MPa (range 0.1–70 MPa). The nearest phylogenetic neighbours were Muricauda antarctica CGMCC 1.2174T and Muricauda taeanensis JCM 17757T with 16S rRNA gene similarity of 98.7 %. The sole respiratory quinone was menaquinone-6 (MK-6). The major polar lipids were phosphatidylethanolamine (PE), two unidentified aminolipids (AL) and ten unidentified lipids. The major fatty acids of strain MT-229T were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. The G+C content of the genomic DNA was 45.6 mol%. The combined genotypic and phenotypic data indicated that strain MT-229T represents a novel species of the genus Muricauda , for which the name Muricauda hadalis sp. nov. is proposed, with the type strain MT-229T (=DSM 109894T=MCCC 1K04201T). In addition, the whole-genome-based comparisons revealed that the type strains of Muricauda antarctica and Muricauda teanensis belong to a single species. It is, therefore, proposed that M. antarctica be recognized as a heterotypic synonym of M. teanensis.

Muricauda oceani sp. nov., isolated from the East Pacific Ocean

A Gram-stain-negative bacterium, designated strain 501str8T, was isolated from a sediment sample collected from the East Pacific Ocean. 16S rRNA gene sequence analysis revealed that strain 501str8T belonged to the genus Muricauda , with closely related type strains Muricauda aquimarina SW-63T (98.5 %), Muricauda lutimaris SMK-108T (98.3 %) and Muricauda ruestringensis B1T (97.9 %). Up-to-date bacterial core gene set analysis revealed that strain 501str8T represented one independent lineage with M. aquimarina SW-63T. The average nucleotide identity values of strain 501str8T with M. aquimarina SW-63T and M. lutimaris SMK-108T were 80.2 and 81.3 %, respectively. In silico DNA–DNA hybridization values between strain 501str8T and M. aquimarina SW-63T and M. lutimaris SMK-108T were 22.8 and 32.9 %, respectively. The predominant isoprenoid quinone was menaquinone-6, and iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G were the dominant cellular fatty acids. The G+C content of the genomic DNA was 42.8 mol%. Differential phylogenetic distinctiveness and chemotaxonomic differences, together with the phenotypic properties observed in this study, revealed that strain 501str8T could be differentiated from closely related species. Therefore, we propose that strain 501str8T represents a novel species of the genus Muricauda , for which the name Muricauda oceani sp. nov. is suggested. The type strain is 501str8T (=JCM 33902T=MCCC 1K04567T).

Muricauda alvinocaridis sp. nov., isolated from shrimp gill from the Okinawa Trough

A Gram-stain-negative, strictly aerobic, non-motile, long, straight-rod and non-flagellated marine bacterium strain, designated SCR12T, was isolated from the gill of a shrimp collected in the Tangyin hydrothermal field of the Okinawa Trough. The growth temperature was in the range of 16–40 °C and the optimum temperature was 37 °C. Optimal growth occurred at pH 6.5 and in the presence of 3 % (w/v) NaCl. The predominant isoprenoid quinone of strain SCR12T was menaquinone-6 (MK-6). The predominant fatty acids (>10 %) were iso-C15 : 0 (44.2 %), iso-C15 : 1 G (19.0 %) and iso-C17 : 0 3-OH (12.1 %). The major polar lipids comprised one phosphatidylethanolamine, three unidentified phospholipids, two unidentified aminolipids and three unidentified lipids. Based on the results of 16S rRNA gene sequence analysis, strain SCR12T was found to be most closely related to Muricauda olearia CL-SS4T (98.09 %), followed by Muricauda beolgyonensis BB-My12T (97.65 %), Muricauda aquimarina SW-63T (97.58 %) and Muricauda ruestringensis DSM 13258T (97.31 %) and with lower sequence similarities (95.74–97.10 %) to other species of the genus Muricauda . Genome relatedness between strain SCR12T and M. olearia CL-SS4T was computed using both average nucleotide identity (ANI) and DNA–DNA hybridization (DDH) and resulted in values of 85.6 % and 29.3±2.3 %, respectively. The genomic DNA G+C content of strain SCR12T was 42.3 mol%. On the basis of polyphasic analysis, the strain SCR12T was considered to represent a novel species of the genus Muricauda, for which the name Muricauda alvinocaridis sp. nov. is proposed. The type strain is SCR12T (=MCCC 1K03731T=JCM 33425T).

Coraliitalea coralii gen. nov., sp. nov., a Marine Bacterium of the Family Flavobacteriaceae Isolated from the Hard Coral Galaxea fascicularis

A polyphasic taxonomic study was performed on a novel strain designated as 04OKA-3-121^T, which was isolated from the hard coral Galaxea fascicularis L. collected at Akajima, Okinawa, Japan. These bacterial cells were observed to be pale-yellow, Gram-stain-negative, strictly aerobic, chemoheterotrophic, non-spore forming, non-motile, and rod-shaped. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the novel marine isolate is affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and that it shared the highest (93.6%) sequence similarity with Pseudozobellia thermophila KMM 3531^T. The strain could be phenotypically differentiated from related members of the family Flavobacteriaceae. Major fatty acids of strain 04OKA-3-121^T were iso-C15:0, iso-C15:1 G, and C16:1 ω7c and/or C16:1 ω6c. The DNA G + C content of the strain was determined to be 38.8 mol% and the major respiratory quinone was identified as menaquinone 6 (MK-6). Strain 04OKA-3-121^T had phosphatidylethanolamine, two unidentified aminolipids, and eight unidentified lipids as polar lipids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus in the family Flavobacteriaceae, for which the name Coraliitalea coralii gen. nov., sp. nov. is proposed. The type strain of C. coralii gen. nov., sp. nov. is 04OKA-3-121^T (= KCTC 52378^T = NBRC 112329^T).

Pacificibacter aestuarii sp. nov., isolated from a tidal flat

A Gram-stain-negative, strictly aerobic bacterium, designated KJ21T, was isolated from a tidal flat in South Korea. Cells were non-motile rods showing oxidase- and catalase-positive activities. Growth of strain KJ21T was observed at 10-35 °C (optimum, 30 °C), at pH 6.0-8.5 (optimum, pH 7.0) and in the presence of 1-5 % (w/v) NaCl (optimum, 2 %). Strain KJ21T contained summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0, 10-methyl C19 : 0 and C10 : 0 3-OH as the major fatty acids and ubiquinone-10 as the major isoprenoid quinone. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unknown aminolipid and an unknown lipid were detected as the major polar lipids. The G+C content of the genomic DNA was 53.9 mol%. Phylogenic analysis based on 16S rRNA gene sequences showed that strain KJ21T formed a tight phylogenetic lineage with the members of the genus Pacificibacter with a 100 % bootstrap value. Strain KJ21T was most closely related to Pacificibacter maritimus KMM 9031T (98.7 %) and Pacificibacter marinus HDW-9T (98.4 %), and the DNA-DNA relatedness values between strain KJ21T and the type strains of P. maritimus and P. marinus were 46.9±4.2 % and 39.8±5.7, respectively. On the basis of phenotypic, chemotaxonomic and molecular properties, it is clear that strain KJ21T represents a novel species of the genus Pacificibacter, for which the name Pacificibacter aestuarii sp. nov. is proposed. The type strain is KJ21T (=KACC 19098T=JCM 31805T).

Revised phylogeny of Bacteroidetes and proposal of sixteen new taxa and two new combinations including Rhodothermaeota phyl. nov

Members of the phylum Bacteroidetes, which was originally defined as a monophyletic branch encompassing the genera Cytophaga, Flavobacterium and Bacteroides (CFB), are widely studied due to their importance in environmental and gut microbiology. As a consequence, the number of species names with standing in nomenclature has doubled in the past five years. In this study, a revision of an earlier phylogeny of Bacteroidetes has been performed using the 16S rRNA gene as a backbone in combination with the 23S rRNA gene, as well as multilocus sequence analysis (MLSA) of 29 orthologous protein sequences, and indels in the sequences of the beta subunit of the F-type ATPase and the alanyl-tRNA synthetase. In addition, taxonomic data for Bacteroidetes has been updated by considering the orphan species list, signature nucleotides in the 16S rRNA sequence, the list of outlier species, and discrepancies with the current taxonomy at the genus rank level. As a result, seven new taxa are proposed within Bacteroidetes (Chitinophagia classis nov., Chitinophagales ord. nov., Crocinitomicaceae fam. nov., Odoribacteraceae fam. nov., Hymenobacteraceae fam. nov., Thermonemataceae fam. nov. and Persicobacteraceae fam. nov.), as well as one new phylum Rhodothermaeota phyl. nov. that contains two classes, two orders, four families and a new genus with two new combinations.

Muricauda pacifica sp. nov., isolated from seawater of the South Pacific Gyre

A Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding, oxidase- and catalase-positive, rod-shaped and orange-pigmented bacterium with appendages, designated strain SW027T, was isolated from a surface seawater sample collected from the South Pacific Gyre (26° 29′ S 137° 56′ W) during the Integrated Ocean Drilling Program (IODP) Expedition 329. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW027T shared the highest sequence similarity with members of the genus Muricauda (94.3–92.7 %), exhibiting 94.3 % sequence similarity to Muricauda flavescens SW-62T. Optimal growth occurred in the presence of 3 % (w/v) NaCl, at pH 7.0 and at 37 °C. The DNA G+C content of strain SW027T was 42.7 mol%. The major fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The major respiratory quinone was menaquinone-6. The major polar lipids were phosphatidylethanolamine and two unidentified lipids. Enzymic activity profiles, cell morphology and DNA G+C content differentiated the novel bacterium from the most closely related members of the genus Muricauda. On the basis of the polyphasic analyses, strain SW027T is considered to represent a novel species of the genus Muricauda, for which the name Muricauda pacifica sp. nov. is proposed. The type strain is SW027T ( = JCM 17861T = LMG 26637T).

A new antibacterial amino phenyl pyrrolidone derivative from a novel marine gliding bacterium Rapidithrix thailandica

A recently described marine gliding bacterium Rapidithrix thailandica strain TISTR 1741 was isolated from biofilm specimen collected from the Andaman Sea in Thailand. Four liters fermentation broth of R. thailandica TISTR 1741 cultivated in VY/2 medium were extracted with methanol to yield a novel amino phenyl pyrrolidone derivative compound (1) with antibacterial activities. The chemical structure and physico-chemical properties of 1 were investigated by spectrometry techniques. Compound 1 exhibited selective inhibition against vancomycin-resistant Enterococcus faecalis (VRE) with the MIC of 5.97 mM.