Gilvimarinus gilvus sp. nov. and Gilvimarinus algae sp. nov., isolated from kelp seedlings

Two novel rod-shaped, strictly aerobic, non-motile and Gram-stain-negative bacterial strains, designated SDUM040013T and SDUM040014T, were isolated from kelp seedlings in Weihai, PR China. Cells of strain SDUM040013T were 0.3-0.4 µm wide and 0.8-1.8 µm long, catalase-positive and oxidase-positive. Growth of SDUM040013T was observed at 0-37 °C (optimum, 28-30 °C) and pH 5.5-9 (optimum, pH 8.0) and in the presence of 1-8 % (w/v) NaCl (optimum, 2 %). The DNA G+C content of strain SDUM040013T was 50.5 %. Strain SDUM040013T showed the highest 16S rRNA gene sequence similarity (97.1 %) to Gilvimarinus chinensis. Cells of strain SDUM040014T were 0.4-0.5 µm wide and 1.0-1.4 µm long, catalase-positive and oxidase-positive. Growth of SDUM040014T was observed at 4-40 °C (optimum, 28-30 °C) and pH 5.5-9 (optimum, pH 8.5) and in the presence of 0-8 % (w/v) NaCl (optimum, 2 %). The DNA G+C content of strain SDUM040014T was 56.5 %. Strain SDUM040014T showed the highest 16S rRNA gene sequence similarity (96.2%) to Gilvimarinus polysaccharolyticus. The isoprenoid quinone of both strains was Q-8 and the predominant fatty acids were summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c), summed feature 8 (C18 : 1  ω7c) and C16 : 0. Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids. Given these phenotypic and chemotaxonomic properties, as well as phylogenetic data, strains SDUM040013T and SDUM040014T were considered to represent two novel species of the genus Gilvimarinus, for which the names Gilvimarinus gilvus sp. nov. and Gilvimarinus algae sp. nov. are proposed. The type strains are SDUM040013T (=KCTC 8123T=MCCC 1H01413T) and SDUM040014T (=KCTC 8124T=MCCC 1H01414T), respectively.

Winogradskyella pelagia sp. nov., isolated from coastal sediment

An orange-pigmented, Gram-stain-negative, strictly aerobic, non-flagellated and rod-shaped bacterium, designated strain DF17T, was isolated from coastal sediment collected from Jingzi Wharf, Weihai, PR China. The optimal growth conditions were determined to be at 30 °C, pH 7.5, and in 3 % (w/v) NaCl. According to phylogenetic analysis of the 16S rRNA gene sequence, strain DF17T showed the highest sequence similarity of 96.9 % to Winogradskyella aquimaris KCTC 23502T. The DNA G+C content was 35.8 mol%, and the major fatty acids were iso-C15 : 1 G, iso-C15 : 0, and iso-C17 : 0 3-OH. The major polar lipids were two aminoglycolipids, one phosphatidylethanolamine and four unidentified lipids. The predominant respiratory quinone was menaquinone-6 (MK-6). The average nucleotide identity, digital DNA-DNA hybridization, and amino acid identity values between strain DF17T and other Winogradskyella species were below the species delineation thresholds of 69.35-72.95 %, 16.9-19.6 % and 71.25-78.93 %, respectively. On the basis of its phenotypic, genetic and physiological characteristics, strain DF17T is suggested to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella pelagia sp. nov. is proposed. The type strain is DF17T (MCCC 1H00456T=KCTC 82421T).

Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov., isolated from marine sediment

Two Gram-stain-negative, rod-shaped, non-motile, strictly aerobic strains, forming yellow colonies and designated F6058T and S2608T, were isolated from marine sediment collected in Weihai, PR China. Both strains grow at 4-40 °C (optimum, 30-33 °C), pH 6.0-7.5 (optimum, pH 6.5) and in the presence of 0-7.0 % (w/v) NaCl. The optimum NaCl concentrations for strains F6058T and S2608T were 2.0 % and 2.5 %, respectively. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strains F6058T and S2608T share an evolutionary lineage with members of the genus Aequorivita. The isolates exhibited a 16S rRNA gene sequence similarity of 96.7 % to each other. Strains F6058T exhibited the highest 16S rRNA gene sequence similarity to Aequorivita xiaoshiensis F64183T (98.8 %), and S2608T was most similar to Aequorivita capsosiphonis A71T (96.9 %). Iso-C15:0, anteiso-C15:0 and iso-C17:0 3-OH were the major fatty acids of strains F6058T and S2608T. The sole respiratory quinone of both isolates was menaquinone 6 (MK-6). The polar lipid profiles of the isolates both consisted of phosphatidylethanolamine and phosphoglycolipids; however, strain F6058T exhibited one glycolipid, one aminolipid and two unidentified polar lipids, and strain S2608T also had two glycolipids and one unidentified polar lipid. The DNA G+C contents of strains F6058T and S2608T were 34.6 % and 37.7 mol%, respectively. Based on their phenotypic, chemotaxonomic and genomic characteristics, strains F6058T and S2608T were considered to represent novel species of the genus Aequorivita, for which the names Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov. were proposed. The type strains are F6058T (=KCTC 92653T=MCCC 1H01358T) and S2608T (KCTC 92652T=MCCC 1H01361T).

Ottowia cancrivicina sp. nov., isolated from human stomach

A Gram-negative, facultative anaerobic, non-motile and rod-shaped bacterium, designated 10c7w1T, was isolated from a human gastrointestinal tract. Colonies on agar plates were small, circular, smooth and beige. The optimal growth conditions were determined to be 37 °C, pH 7.0-7.5 and 0 % (w/v) NaCl. Comparative analysis of complete 16S rRNA gene sequences revealed that strain 10c7w1T showed the highest sequence similarity of 95.8 % to Ottowia beijingensis MCCC 1A01410T, followed by Ottowia thiooxydans (95.2 %) JCM 11629T. The average amino acid identity values between 10c7w1T and O. beijingensis MCCC 1A01410T and O. thiooxydans JCM 11629T were above 60 % (71.4 and 69.5 %). The average nucleotide identity values between strain 10c7w1T and O. beijingensis MCCC 1A01410T and O. thiooxydans JCM 11629T were 76.9 and 72.5 %, respectively. The dominant fatty acids (≥10 %) were straight chain ones, with summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c), summed feature 8 (C18 : 1  ω7c/C18 : 1  ω6c) and C16 : 00 being the most abundant. Q-8 was the only respiratory quinone. The major polar lipids of strain 10c7w1T were phosphatidylethanolamine, diphosphatidylglycerol and unknown lipids. The DNA G+C content of strain 10c7w1T was 63.6 mol%. On the basis of phylogenetic, phenotypic and chemotaxonomic data, strain 10c7w1T is considered to represent a novel species within the genus Ottowia, for which the name Ottowia cancrivicina sp. nov. is proposed. The type strain is 10c7w1T (=MCCC 1H01399T=KCTC 92200T).

Analysis of the complete genome sequence of Paenibacillus sp. lzh-N1 reveals its antagonistic ability

BACKGROUND

Plant diseases caused by pathogenic fungi are devastating. However, commonly used fungicides are harmful to the environment, and some are becoming ineffective due to fungal resistance. Therefore, eco-friendly biological methods to control pathogenic fungi are urgently needed.

RESULTS

In this study, a strain, Paenibacillus sp. lzh-N1, that could inhibit the growth of the pathogenic fungus Mycosphaerella sentina (Fr) Schrorter was isolated from the rhizosphere soil of pear trees, and the complete genome sequence of the strain was obtained, annotated, and analyzed to reveal the genetic foundation of its antagonistic ability. The entire genome of this strain contained a circular chromosome of 5,641,488 bp with a GC content of 45.50%. The results of species identification show that the strain belongs to the same species as P. polymyxa Sb3-1 and P. polymyxa CJX518. Sixteen secondary metabolic biosynthetic gene clusters were predicted by antiSMASH, including those of the antifungal peptides fusaricidin B and paenilarvins. In addition, biofilm formation-related genes containing two potential gene clusters for cyclic lactone autoinducer, a gene encoding S-ribosylhomocysteine lyase (LuxS), and three genes encoding exopolysaccharide biosynthesis protein were identified.

CONCLUSIONS

Antifungal peptides and glucanase biosynthesized by Paenibacillus sp. lzh-N1 may be responsible for its antagonistic effect. Moreover, quorum sensing systems may influence the biocontrol activity of this strain directly or indirectly.

Xiashengella succiniciproducens gen. nov., sp. nov., a succinate-producing bacterium isolated from an anaerobic digestion tank in the family Marinilabiliaceae of the order Bacteroidales

A strictly anaerobic, motile bacterium, designated as strain Ai-910T, was isolated from the sludge of an anaerobic digestion tank in China. Cells were Gram-stain-negative rods. Optimal growth was observed at 38 °C (growth range 25-42 °C), pH 8.5 (growth range 5.5-10.5), and under a NaCl concentration of 0.06% (w/v) (range 0-2.0%). Major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The respiratory quinone was MK-7. Using xylose as the growth substrate, succinate was produced as the fermentation product. Phylogenetic analysis based on the 16 S rRNA gene sequences indicated that strain Ai-910T formed a distinct phylogenetic lineage that reflects a new genus in the family Marinilabiliaceae, sharing high similarities to Alkaliflexus imshenetskii Z-7010T (92.78%), Alkalitalea saponilacus SC/BZ-SP2T (92.51%), and Geofilum rubicundum JAM-BA0501T (92.36%). Genomic similarity (average nucleotide identity and digital DNA-DNA hybridization) values between strain Ai-910T and its phylogenetic neighbors were below 65.27 and 16.90%, respectively, indicating that strain Ai-910T represented a novel species. The average amino acid identity between strain Ai-910T and other related members of the family Marinilabiliaceae were below 69.41%, supporting that strain Ai-910T was a member of a new genus within the family Marinilabiliaceae. Phylogenetic, genomic, and phenotypic analysis revealed that strain Ai-910T was distinguished from other phylogenetic relatives within the family Marinilabiliaceae. The genome size was 3.10 Mbp, and the DNA G + C content of the isolate was 42.8 mol%. Collectively, differences of the phenotypic and phylogenetic features of strain Ai-910T from its close relatives suggest that strain Ai-910T represented a novel species in a new genus of the family Marinilabiliaceae, for which the name Xiashengella succiniciproducens gen. nov., sp. nov. was proposed. The type strain of Xiashengella succiniciproducens is Ai-910T (= CGMCC 1.17893T = KCTC 25,304T).

Cultivating the uncultured: Harnessing the "sandwich agar plate" approach to isolate heme-dependent bacteria from marine sediment

In the classical microbial isolation technique, the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for survival. In this study, we designed a simple coculture technique named the "sandwich agar plate method," which maintains microbial interactions throughout the isolation and pure culture processes. The total yield of uncultured species in sandwich agar plates based on eight helper strains was almost 10-fold that of the control group. Many uncultured species displayed commensal lifestyles. Further study found that heme was the growth-promoting factor of some marine commensal bacteria. Subsequent genomic analysis revealed that heme auxotrophies were common in various biotopes and prevalent in many uncultured microbial taxa. Moreover, our study supported that the survival strategies of heme auxotrophy in different habitats varied considerably. These findings highlight that cocultivation based on the "sandwich agar plate method" could be developed and used to isolate more uncultured bacteria.

Brumimicrobium oceani sp. nov., isolated from coastal sediment saline lake and environmental adaptability analysis

A novel Gram-stain-negative, aerobic, non-motile, rod-shaped and orange-colored bacterium, designated as strain C305T, was isolated from marine sediment of the coast area of Weihai, China. Strain C305T growth occurs at 4-40 °C (optimally at 30-33 °C), pH 6.0-9.0 (optimally at pH 8.0) and with 0.5-10.0% (w/v) NaCl (optimum 1.5-3.0%). No growth is observed without NaCl. The major cellular fatty acids of strain C305T were identified as iso-C15:0, iso-C15:1G and iso-C17:0 3-OH. The major respiratory quinone was found to be MK-6, and the DNA G + C content was determined to be 35.5 mol%. The predominant polar lipids were mainly phosphatidylethanolamines (PE), unidentified aminophospholipids (APL), andunidentified lipid (L2). Phylogenetic analysis based on 16S rRNA gene sequences revealed that C305T was a member of the genus Brumimicrobium and had a 16S rRNA gene sequence similarity values of 96.9-98.0% with recognized Brumimicrobium species. On the basis of the phylogenetic and phenotypic evidences, strain C305T represents a novel species of the genus Brumimicrobium, for which the name Brumimicrobium oceani sp. nov. is proposed. The type strain is C305T (= KCTC 62371 T = MCCC 1H00297T).

Marinicella marina sp. nov. and Marinicella gelatinilytica sp. nov., isolated from coastal sediment, and genome analysis and habitat distribution of the genus Marinicella

Three Marinicella strains, X102, S1101T and S6413T, were isolated from sediment samples from different coasts of Weihai, PR China. All strains were Gram-stain-negative, rod-shaped and non-motile. The predominant fatty acids of all strains were iso-C15 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c) and the major polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Strains X102 and S1101T shared 100 % 16S rRNA gene sequence similarity, and strains S1101T/X102 and S6413T had 95.4 % similarity. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains S1101T and X102 were 99.9 and 99.2 %, respectively. Strain S1101T had ANI values of 69.1-72.9% and dDDH values of 17.9-20.5 % to members of the genus Marinicella. Strain S6413T had ANI values of 69.1-77.5% and dDDH values of 17.6-21.5 % to members of the genus Marinicella. The results of phylogenetic and comparative genomic analysis showed that the three strains belong to two novel species in the genus Marinicella, and strains X102 and S1101T represented one novel species, and strain S6413T represented another novel species. The result of BOX-PCR and genomic analysis showed that X102 and S1101T were not the same strain. The phylogenetic analyses and genomic comparisons, combined with phylogenetic, phenotypic and chemotaxonomic features, strongly supported that the three strains should be classified as representing two novel species of the genus Marinicella, for which the names Marinicella marina sp. nov. and Marinicella gelatinilytica sp. nov. are proposed, respectively. The type strains of the two novel species are S1101T (=KCTC 92642T=MCCC 1H01359T) and S6413T (=KCTC 92641T=MCCC 1H01362T), respectively. In addition, all previously described isolates of Marinicella were isolated from marine environments, but our study showed that Marinicella is also distributed in non-/low-saline habitats (e.g. animal gut, soil and indoor surface), which broadened our perception of the environmental distribution of Marinicella.

Tumebacillus lacus sp. nov., isolated from lake water

A Gram-stain-positive, aerobic, rod-shaped, endospore-forming and motile, by means of peritrichous flagella, bacterium, designated DT12T, was isolated from a lake water sample from Datun Lake of Yunnan Province, PR China. The results of phylogenetic analysis based on 16S rRNA gene sequence and the concatenated alignment of 120 ubiquitous single-copy proteins indicated that the novel strain represented a member of the genus Tumebacillus. The sole quinone was menaquinone-7 and the cell-wall peptidoglycan was type-A1γ. The major fatty acids (>10 %) of the novel strain were iso-C15 : 0 and anteiso-C15 : 0, while the major polar lipids were phosphatidylmonomethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. The results of phylogenetic analyses combined with phylogenetic, phenotypic and chemotaxonomic features, strongly supported the hypothesis that the strain should be classified as representing a novel species of the genus Tumebacillus, for which the name Tumebacillus lacus sp. nov. is proposed. The type strain is DT12T (=KCTC 33958T= MCCC 1H00320T). The genomic analysis revealed that DT12T has various biosynthetic gene clusters for secondary metabolites, and members of the genus Tumebacillus may represent a promising source of new natural products. Our study also showed that members of the genus Tumebacillus are widely distributed in a variety of habitats throughout the globe, particularly in soils, human-, animal- and plant-associated environments. Members of the genus Tumebacillus may have an important role in the growth and health of humans, plants and animals.

Marinihelvus fidelis gen. nov., sp. nov., isolated from marine sediment, and genomic comparison with multiple genera

A Gram-stain-negative, rod-shaped, non-gliding, non-flagellated, yellow, facultatively aerobic bacterial strain, designated as W260T, was isolated from marine sediment of Xiaoshi Island, Weihai, PR China. The cells of W260T were 0.3-0.5 µm wide and 1.5-2.0 µm long. Strain W260T grows optimally at a temperature of 33 °C (range, 15-37 °C), pH 8 (range, pH 6.5-9.5) and witha NaCl concentration of 3.0 % (w/v; range, 1-8 %). It has the highest sequence similarity to Thiohalobacter thiocyanaticus DSM 21152T (91.7 %), followed by Wenzhouxiangella marina MCCC 1K00261T (91.4 %) and Thiohalospira alkaliphila DSM 17116T (90.7 %). The similarity between strain W260T and the species Thiohalophilus thiocyanatoxydans DSM 16326T was 89.4 %. Genome sequencing revealed a genome size of 3 430 000 bp and a DNA G+C content of 64.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain W260T and W. marina MCCC 1K00261T were 69.6 and 16.1-20.6 %, respectively. The predominant quinone was ubiquitin-8, and the major fatty acids were iso-C14 : 0 and iso-C16 : 0. The polar lipids consisted of phosphatidylethanolamine, phospholipid, phosphatidylglycerol, diphosphatidylglycerol and four unidentified lipids. Based on phenotypic, phylogenetic and chemotaxonomic information, it was determined that strain W260T represents a novel genus and species and it was given the name Marinihelvus fidelis sp. nov. The type strain is W260T (=MCCC 1H00471T=KCTC 92639T).

Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov., isolated from coastal sediment

Two novel rod-shaped, Gram-stain-negative, aerobic and non-motile bacterial strains, designated M39T and C2-7T, were isolated from the coastal sediment of Xiaoshi Island, Weihai, PR China. Growth of strain M39T occurred at 15-37 °C, at pH 6.0-9.0 and in the presence of 1.0-9.0 % (w/v) NaCl. Strain C2-7T grew at 15-40 °C, at pH 6.0-8.0 and in the presence of 0.5-8.0 % (w/v) NaCl. Phylogenetic analysis based 16S rRNA gene sequences revealed that strains M39T and C2-7T belong to the phylum Bacteroidota. Based on the results of 16S rRNA gene sequence analysis, the closest relative of strain M39T was Robiginitalea marina KCTC 92035T (95.4 %), and the closest relative of strain C2-7T was Algoriphagus namhaensis DPG-3T (97.0 %). The percentage of conserved protein and average nucleotide identity values between strain M39T and some species of the genus Robiginitalea were 66.9-77.6% and 69.3-71.0 %, respectively, while those between strain C2-7T and some species of the genus Algoriphagus were 68.0-70.1% and 56.1-72.6 %, respectively. The major cellular fatty acids (>10 %) of strain M39T consisted of iso-C15 : 1 F, iso-C15 : 0 and iso-C17 : 0 3-OH, while those of strain C2-7T were iso-C15 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. MK-6 was the only respiratory quinone that was compatible with the genus of strain M39T. The predominant menaquinone of strain C2-7T was MK-7. The major polar lipids of strain M39T were phosphatidylethanolamine and glycolipids, and those of strain C2-7T were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. The DNA G+C contents of strains M39T and C2-7T were 46.9 and 40.8 mol%, respectively. Based upon the results presented in this study, strains M39T and C2-7T represent novel species of the genera Robiginitalea and Algoriphagus, respectively, for which the names Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov. are proposed with the type strains M39T (=MCCC 1H00498T=KCTC 92014T) and C2-7T (=MCCC 1H00414T=KCTC 92027T).

Bioprospecting for the soil-derived actinobacteria and bioactive secondary metabolites on the Western Qinghai-Tibet Plateau

Introduction

The increase in incidence of multidrug-resistant bacteria and the inadequacy of new antimicrobial drugs have led to a widespread outbreak of bacterial antimicrobial resistance. To discover new antibiotics, biodiversity, and novelty of culturable actinobacteria dwelled in soil of the Western Qinghai-Tibet Plateau were investigated. By integrating antibacterial assay with omics tools, Amycolatopsis sp. A133, a rare actinobacterial strain and its secondary metabolites were further studied.

Method

Culture-dependent method was used to obtain actinobacterial strains from two soil samples collected from Ali region in Qinghai-Tibet Plateau. The cultural extractions of representative strains were assayed against "ESKAPE" pathogens by paper-disk diffusion method and the double fluorescent protein reporter "pDualrep2" system. An Amycolatopsis strain coded as A133 was prioritized and its secondary metabolites were further analyzed and annotated by omics tools including antiSMASH and GNPS (Global Natural Social Molecular Networking). The predicted rifamycin analogs produced by Amycolatopsis sp. A133 were isolated and identified by chromatographic separation, such as Sephadex LH-20 and HPLC, and spectral analysis, such as NMR and UPLC-HRESI-MS/MS, respectively.

Results

A total of 406 actinobacteria strains affiliated to 36 genera in 17 families of 9 orders were isolated. Out of 152 representative strains, 63 isolates exhibited antagonistic activity against at least one of the tested pathogens. Among them, 7 positive strains were identified by the "pDualrep2" system as either an inhibitor of protein translation or DNA biosynthesis. The cultural broth of Amycolatopsis sp. A133 exhibited a broader antimicrobial activity and can induce expression of TurboRFP. The secondary metabolites produced by strain A133 was annotated as rifamycins and zampanolides by antiSMASH and GNPS analysis. Five members of rifamycins, including rifamycin W, protorifamycin I, rifamycin W-M1, proansamycin B, and rifamycin S, were purified and identified. Rifamycin W-M1, was found as a new member of the naturally occurring rifamycin group of antibiotics.

Discussion

Assisted by omics tools, the successful and highly efficient discovery of rifamycins, a group of clinically used antibiotics from actinobacteria in Ali area encouraged us to devote more energy to explore new antibiotics from the soils on the Western Tibetan Plateau.

Halocynthiibacter halioticoli sp. nov., isolated from the viscera of abalone Haliotis discus hannai

A Gram-stain-negative, rod-shaped, glide, non-flagellated, and facultatively anaerobic bacterial strain, designated as Z654T, was isolated from the gut of abalone Haliotis discus hannai from Rongcheng, Shandong province, China. Cells are 0.2-0.8 μm in width and 0.7-3.4 μm in length. Cells grew best at 30 °C (range, 15-37 °C), pH 7.0 (range, 6.0-8.5) and NaCl concentration of 2.0% (w/v) (range, 1-10%). According to the phylogenetic analysis of 16S rRNA gene sequence, the strain belongs to the genus Halocynthiibacter and the closest strain is Halocynthiibacter arcticus KCTC 42129 T (97.12%). The genome size of strain Z654T was 3,296,250 bp and the DNA G + C content was 54.2 mol%. The average nucleotide identity (ANI) scores and digital DNA-DNA hybridization (dDDH) scores with H. arcticus KCTC 42129 T were 70% and 14.6-18.2%, respectively. The predominant quinone was Q-10 and the major fatty acids were C18:0, C18:1 ω7c 11-methyl and summed feature 8. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, unidentified aminolipid and unidentifed lipids. Based on the phenotypic, phylogenetic and chemotaxonomic data, strain Z654T was considered to represent a novel species of the genus Halocynthiibacter, for which the name Halocynthiibacte halioticoli sp. nov., is proposed. The type strain is Z654T (= MCCC 1H00503T = KCTC 92003 T).

Winogradskyella vincentii sp. nov. and Winogradskyella alexanderae sp. nov., two novel bacteria isolated from intertidal sediment

Two novel Gram-stain-negative, facultative anaerobic, chemoheterotrophic, non-motile and rod-shaped strains were isolated from intertidal sediment sampled at Xiaoshi Island, Weihai, PR China. Full sequence analysis of the 16S rRNA genes showed that the two strains were closely related to members of the genus Winogradskyella and the phylogenetic similarities to their closest relative, Winogradskyella aquimaris, were 96.7 and 95.8 %, respectively. The DNA G+C contents of strains 2Y89T and D23T were 33.3 and 35.1 mol%, respectively. The respiratory quinone detected in both strains was MK-6. The major fatty acids detected in strain 2Y89T were iso-C15 : 0 and iso-C15 : 1G, and in strain D23T they were iso-C15 : 1G, iso-C15 : 0 and iso-C17 : 03-OH. The principal polar lipids of strain 2Y89T mainly included phosphatidylethanolamine, aminoglycolipids, unidentified aminolipids, unidentified glycolipids and unidentified lipids; strain D23T was the same as strain 2Y89T except that it did not contain aminoglycolipids. Based on the phenotypic, chemical taxonomic, genotypic and phylogenetic features established in this study, we suggest that the new strains represent two novel species of the genus Winogradskyella, for which the names Winogradskyella vincentii sp. nov. (type strain 2Y89T=MCCC 1H00477T=KCTC 92034T) and Winogradskyella alexanderae sp. nov. (type strain D23T=MCCC 1H00462T=KCTC 92023T) are proposed.

Aliiroseovarius subalbicans sp. nov. and Aliiroseovarius sediminis sp. nov., isolated from marine sediment

Two novel strains (N1Y82^T and N1F302^T) were isolated from a marine sediment sample taken from the coastal zone of Weihai, PR China. Cells of the two strains were Gram-strain-negative, catalase-positive, oxidase-positive, non-motile and ovoid- to rod-shaped. Strain N1Y82^T grew optimally at 16 °C, pH 7.5 and in the presence of 3.0 % (w/v) NaCl. Strain N1F302^T grew optimally at 28 °C, pH 7.0-7.5 and in the presence of 2.0-2.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strains N1Y82^T and N1F302^T belonged to the genus Aliiroseovarius, and were mostly related to Aliiroseovarius sediminilitoris KCTC 23959^T with sequence similarity of 96.5 and 97.1 %, respectively. For these two novel strains, C_18 : 1 ω7c was the major fatty acid, ubiquinone 10 was the predominant respiratory quinone, and phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, one unidentified aminolipid and one unidentified phospholipid were the major polar lipids. The DNA G+C contents of strain N1Y82^T and N1F302^T were 61.3 and 59.0 %, respectively. Consequently, strains N1Y82^T and N1F302^T are considered to represent two novel species of the genus Aliiroseovarius, for which the names Aliiroseovarius subalbicans sp. nov. and Aliiroseovarius sediminis sp. nov. are proposed. The type strains are N1Y82^T (=KCTC 82768^T=MCCC 1H00524^T) and N1F302^T (=KCTC 82412^T=MCCC 1H00525^T), respectively.

Description and Genomic Characterization of Oceaniferula flavus sp. nov., a Novel Potential Polysaccharide-Degrading Candidate of the Difficult-to-Cultivate Phylum Verrucomicrobiota Isolated from Seaweed

A novel strain, isolate 5K15^T, which belongs to difficult-to-cultivate phylum Verrucomicrobiota, was recovered from kelp collected from Li Island, Rongcheng, China. The genome sequence of the strain (genome size 3.95 Mbp) showed the presence of four putative biosynthetic gene clusters (BGCs), namely, two terpene biosynthetic gene clusters, one aryl polyene biosynthetic cluster, and one type III PKS cluster. Genomic analysis revealed 79 sulfatase-encoded genes, 24 sulfatase-like hydrolase/transferase-encoded genes, and 25 arylsulfatase-encoded genes, which indicated the great potential of 5K15^T to degrade sulfated polysaccharides. Comparative analysis of 16S rRNA gene sequence showed that the novel strain was most closely related to Oceaniferula marina N1E253^T (96.4%). On the basis of evidence from a polyphasic study, it is proposed that the strain 5K15^T (= KCTC 82748^T = MCCC 1H00442^T = SDUM 810003^T) be classified as Oceaniferula flavus sp. nov. The strain has the ability of carbohydrate transport and metabolism. This ability allows it to survive in carbohydrate-rich materials such as kelp. It has the potential to be used in the marine drug industry using seaweed.

Elasmobranch-associated microbiota: a scientometric literature review

Elasmobranchs provide greatly relevant ecosystem services for the balance of the environments in which they are inserted. In recent decades, sharp population declines have been reported for many species in different regions worldwide, making this taxonomic group currently one of the most threatened with extinction. This scenario is almost entirely due to excessive fishing pressure, but any contributing factor that may cause additional mortality to populations must be mapped and monitored. In a fast-changing world, emerging marine pollution associated with climate change display the potential to increase the spread of infectious agents. These can, in turn, lead to mortality events, both directly and indirectly, by reducing immune responses and the physical and nutritional condition of affected individuals. In this context, the present study aimed to analyze data concerning elasmobranch-associated microbiota, identifying study trends and knowledge gaps in order to direct future studies on this topic of growing relevance for the health of wild populations, as well as individuals maintained in captivity, considering the zoonotic potential of these microorganisms.

Comparative genomic analysis of the genus Marinomonas and taxonomic study of Marinomonas algarum sp. nov., isolated from red algae Gelidium amansii

Members of the genus Marinomonas are known for their environmental adaptation and metabolically versatility, with abundant proteins associated with antifreeze, osmotic pressure resistance, carbohydrase and multiple secondary metabolites. Comparative genomic analysis focusing on secondary metabolites and orthologue proteins was conducted with 30 reference genome sequences in the genus Marinomonas. In this study, a Gram-stain-negative, rod-shaped, non-flagellated and strictly aerobic bacterium, designated as strain E8^T, was isolated from the red algae (Gelidium amansii) in the coastal of Weihai, China. Optimal growth of the strain E8^T was observed at temperatures 25-30 °C, pH 6.5-8.0 and 1-3% (w/v) NaCl. The DNA G + C content was 42.8 mol%. The predominant isoprenoid quinone was Q-8 and the major fatty acids were C_16:0, summed feature 3 and summed feature 8. The major polar lipids were phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). Based on data obtained from this polyphasic taxonomic study, strain E8^T should be considered as a novel species of the genus Marinomonas, for which the name Marinomonas algarum is proposed. The type strain is E8^T (= KCTC 92201^T = MCCC 1K07070^T).

Rhodococcus yananensis sp. nov., a novel denitrification actinobacterium isolated from microbial fermentation bed material from a pig farm

An opaque, pink-coloured, gram-positive, aerobic bacteria (designated as FBM22-1T), was isolated from microbial fermentation bed material from a pig farm in northwestern China. Optimal growth occurred at 30–37 °C, pH 7.0 and with 0.5 % NaCl (w/v). The strain had nitrification and denitrification functions. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the novel isolate belonged to the genus Rhodococcus . Strain FBM22-1T was closely related to Rhodococcus zopfii NBRC 100606T and Rhodococcus rhodochrous NBRC 16069T, with 16S rRNA gene sequence similarities of 97.9 and 97.7 %, respectively. The predominant menaquinone in strain FBM22-1T was MK-8(H2). The cellular fatty acids consisted primarily of C16 : 1ω7c and/or C16 : 1 ω6c, C16 : 0 and 10-methyl C18 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and glycolipid. The G+C content of strain FBM22-1T was 68.64 mol%. Based on the phenotypic, phylogenetic and chemotaxonomic characterization results, in combination with low values of digital DNA–DNA hybridization between strain FBM22-1T and its closest neighbours, FBM22-1T represents a novel species of the genus Rhodococcus , for which the name Rhodococcus yananensis sp. nov. is proposed; the type strain is FBM22-1T (=KCTC 49502T=CCTCC AB2020275T).

Rhodohalobacter sulfatireducens sp. nov., isolated from a marine solar saltern

A novel Gram-stain-negative, oxidase-positive, catalase-positive, non-motile, facultatively anaerobic, rod-shaped bacterium, designated WB101^T, was isolated from a marine solar saltern located in Wendeng, PR China. Strain WB101^T shared a high level of 16S rRNA gene sequence similarity with Rhodohalobacter barkolensis 15182^T (93.5%), R. halophilus JZ3C29^T (93.2%), and 'R. mucosus' 8A47^T (92.1%). Strain WB101^T formed a species-level branch within the genus Rhodohalobacter in both phylogenetic and phylogenomic topologies. The DNA G + C content was 42.0%. Strain WB101^T was found to have menaquinone-7 as the only respiratory quinone. The dominant cellular fatty acid (≥ 10%) was iso-C_15:0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylcholine. Characterisation based on phylogenetic, physiological, and biochemical properties indicated that strain WB101^T represents a novel species of the genus Rhodohalobacter, and the name Rhodohalobacter sulfatireducens sp. nov. is proposed. The type strain is WB101^T (= KCTC 92204^T = MCCC 1H00518^T).

Microvenator marinus gen. nov., sp. nov., isolated from marine sediment, and description of Microvenatoraceae fam. nov. and Lujinxingiaceae fam. nov

A Gram-stain-negative, facultatively anaerobic, oxidase-negative and catalase-positive predatory bacillus, designated strain V1718T, was isolated from Xiaoshi Island, PR China. Strain V1718T was found to be closely related to Lujinxingia sediminis SEH01T, with 89.8 % similarity in the 16S rRNA gene sequence, followed by Bradymonas sediminis FA350T with a similarity of 88.4 %. Strain V1718T had the ability to prey on other bacteria, and selective predation on members of Algoriphagus , Nocardioides and Bacillus occurred with the strain. Growth was observed within the range of 20–45 °C (optimal at 37 °C), pH 6.5–9.0 (optimal at pH 8.0) and 1–10 % NaCl (optimal at 3–4 %, w/v). The predominant cellular fatty acids in strain V1718T were iso-C15 : 0 (53.0 %) and C16 : 0 (19.1 %). The major polar lipids present in the strain were phosphatidylglycerol and phosphatidylethanolamine, and the respiratory quinone was menaquinone MK-7. The complete genome sequence of strain V1718T was 5 847 748 bp with a G+C content of 55.2 mol%. The topology of the phylogenomic tree indicated that strain V1718T forms a separate branch in the same clade with the genus Lujinxingia and the family Bradymonadaceae . The average nucleotide identity and average amino acid identity values were 66.4 and 48.6 %, respectively, with Bradymonas sediminis FA350T (type species of Bradymonas ) and 66.8 % and 48.9 % with Lujinxingia litoralis B210T (type species of Lujinxingia ). The genes related to biosynthesis pathways of several important chemical compounds could not be found in the genome of strain V1718T, which was predicted to be the intrinsic reason for predation in this group. The physiological, biochemical and phylogenetic properties of strain V1718T suggest that it belongs to a novel family distinct from other culturable bradymonabacteria. The name Microvenator marinus gen. nov., sp. nov. is proposed, with strain V1718T (=KCTC 72082T=MCCC 1H00380T) as type strain; the name Microvenatoraceae fam. nov. is also proposed. Meanwhile, the genus Lujinxingia can also be taxonomic classified as Lujinxingiaceae fam. nov. Thus, two novel families and a novel genus of the order Bradymonadales are proposed in this paper.

Fulvivirga marina sp. nov. and Fulvivirga sediminis sp. nov., two novel Bacteroidetes isolated from the marine sediment

Two novel, designated strains 29W222T and 2943T, were isolated from the marine sediment from Aoshan Bay, Jimo, PR China. Growth was observed at pH 6.0–8.5 (optimum, pH 7.5) for strain 29W222T, and pH 5.5–8.5 (pH 7.0) for strain 2943T. Both strains displayed growth in 0.5–6 % NaCl with an optimum at 1 % for 29W222T; 0.5 % for 2943T. Both strains grew optimally at 33 °C. The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that 29W222T and 2943T represented members of the genus Fulvivirga and strain 29W222T was most closely related to Fulvivirga kasyanovii KMM 6220T (97.9 % sequence similarity) and Fulvivirga imtechensis AK7T (95.0 %), and 2943T to Fulvivirga imtechensis AK7T (95.7 %) and Fulvivirga kasyanovii KMM 6220T (94.8 %). The genomic DNA G+C contents of 29W222T and 2943T were 39.9 and 37.7 mol%, respectively. The results of chemotaxonomic analysis indicated that the sole respiratory quinone was menaquinone 7 (MK-7), and the major fatty acid was iso-C15 : 0 for both strains. Average nucleotide identity and average amino acid identity values between strain 29W222T and Fulvivirga kasyanovii KMM 6220T were 78.9 and 83.6 %, respectively; the corresponding values between 2943T and Fulvivirga imtechensis AK7T were 69.8 and 63.6 %, respectively. Therefore, strains 29W222T and 2943T represent to two novel species of the genus Fulvivirga , for which the names Fulvivirga marina sp. nov. (29W222T=KCTC 62848T=MCCC 1K05194T) and Fulvivirga sediminis sp. nov. (2943T=KCTC 62847T= MCCC 1K05144T) are proposed, respectively.

Aliidiomarina halalkaliphila sp. nov., a haloalkaliphilic bacterium isolated from a soda lake in Inner Mongolia Autonomous Region, China

A haloalkaliphilic strain (IM 1326^T) was isolated from brine sampled at a soda lake in the Inner Mongolia Autonomous Region, China. Cells of the strain were rod-shaped and motile. Strain IM 1326^T was able to grow at 4–42 °C (optimum, 37 °C) with 0–13.0 % (w/v) NaCl concentrations (optimum at 4.0–6.0 %) and at pH 7.5–11.0 (optimum at 9.0–10.0). The 16S rRNA gene phylogenetic analysis revealed that the isolate belongs to the genus Aliidiomarina and is closely related to the type strains of Aliidiomarina sanyensis (95.8 % sequence similarity), Aliidiomarina shirensis (95.7 %), Aliidiomarina iranensis (95.4 %) and Aliidiomarina haloalkalitolerans (95.3 %). The whole genome of strain IM 1326^T was sequenced, and the genomic DNA G+C content was 49.7 mol%. Average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the isolate and the related Aliidiomarina species were 68.1–84.9 %, 76–78 % and 18.4–20.4 %, respectively. The respiratory quinone was ubiquinone-8. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminophospholipid. The predominant cellular fatty acids were summed feature 9 (10-methyl-C_16 : 0/iso-C_17 : 1 ω9c, 22.2 %), iso-C_15 : 0 (16.1 %) and iso-C_17 : 0 (13.1 %). Based on the results of phylogenetic analysis, genome relatedness, and the physiological and chemotaxonomic properties of the isolate, strain IM 1326^T is considered to represent a novel species of the genus Aliidiomarina, for which the name Aliidiomarina halalkaliphila sp. nov. is proposed (type strain IM 1326^T=CGMCC 1.17056^T=JCM 34227^T).

Psychrobacter halodurans sp. nov. and Psychrobacter coccoides sp. nov., two new slightly halophilic bacteria isolated from marine sediment

In this study, two bacterial strains designated F2608T and F1192T, isolated from marine sediment sampled in Weihai, PR China, were characterized using a polyphasic approach. Strains were aerobic, Gram-stain-negative and motile. According to the results of phylogenetic analyses based on their 16S rRNA genes, these two strains should be classified under the genus Psychrobacter and they both show <98.5% sequence similarity to their closest relative, Psychrobacter celer JCM 12601T. Moreover, strain F2608T showed 97.5% sequence similarity to strain F1192T. Strain F2608T grew at 4–37 °C (optimum, 30–33 °C) and at pH 6.0–9.0 (optimum, pH 6.5–7.0) in the presence of 0–12% (w/v) NaCl (optimum, 4.0–5.0%). Strain F1192T grew at 4–37 °C (optimum, 30 °C) and at pH 5.5–9.0 (optimum, pH 7.0–7.5) in the presence of 0.5–12% (w/v) NaCl (optimum, 3.0–4.0%). The genomic DNA G+C contents of strain F2608T and strain F1192T were 47.4 and 44.9 %, respectively. Genomic characteristics including average nucleotide identity and digital DNA–DNA hybridization values clearly separated strain F2608T from strain F1192T. The sole isoprenoid quinone in these two strains was ubiquinone 8 and the major cellular fatty acids (>10.0%) were C18:1 ω9c and C17:1 ω8c. The major polar lipids of these two strains were phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Based on the results of polyphasic analysis, the two strains represent two novel species of the genus Psychrobacter , for which the names Psychrobacter halodurans sp. nov. and Psychrobacter coccoides sp. nov. are proposed. The type strains are F2608T (=MCCC 1K05774T=KCTC 82766T) and F1192T (=MCCC 1K05775T=KCTC 82765T), respectively.

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

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated strain YQF-2^T, was isolated from coastal sediment sampled in Jiangsu Province and characterized phylogenetically and phenotypically. Optimal bacterial growth occurred at 28 °C (range 4-38 °C) and pH 7 (pH 6-10). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YQF-2^T was related to members of the genus Rheinheimera and shared the highest sequence identities with Rheinheimera pacifica KMM 1406^T (98.6%), followed by Rheinheimera aestuarii H29^T (98.4%), Rheinheimera japonica KMM 9513^T (98.3%), Rheinheimera aquimaris SW-353^T (98.3%), Rheinheimera hassiensis E48^T (97.8%) and Rheinheimera muenzenbergensis E49^T (97.7%). The 16S rRNA gene sequence identities between strain YQF-2^T and other members of the genus Rheinheimera were below 97.2%. The digital DNA-DNA hybridization value between strain YQF-2^T and R. pacifica KMM 1406^T was 23.3±2.3%. The average nucleotide identity value between strain YQF-2^T and R. pacifica KMM 1406^T was 79.7%. The unique respiratory quinone was ubiquinone-8. Phosphatidylethanolamine and phosphatidylglycerol were identified as the major polar lipids. The strain had summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c), C_16:0, C_12:0 3-OH and iso-C_17:0 3-OH as major fatty acids. The G+C content of the genomic DNA was 50.0 mol%. On the basis of phenotypic, genotypic and phylogenetic evidence, strain YQF-2^T represents a novel species of the genus Rheinheimera, for which the name Rheinheimera lutimaris sp. nov. is proposed, with the type strain YQF-2^T (=KCTC 72184^T=MCCC 1K03663^T).

Winogradskyella marina sp. nov., isolated from marine sediment

A Gram-stain-negative, rod-shaped (0.3-0.6 × 0.9-2.2 µm), facultatively aerobic, non-motile and yellow-coloured bacterium, designated strain F6397^T, was isolated from a marine sediment in Weihai, PR China. Growth of strain F6397^T occurred at 4-37 °C (optimum, 30-33 °C), pH 6.0-9.0 (optimum, 7.5) and in the presence of 1-12% (optimum, 3.0%) (w/v) NaCl. Strain F6397^T showed oxidase- and catalase-positive activities. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the strain was assigned to the genus Winogradskyella. Strain F6397^T exhibited 95.5-98.1% sequence similarities to recognized species of the genus Winogradskyella. The average nucleotide identity (ANI) scores with Winogradskyella ludwigii HL116^T, Winogradskyella litoriviva KMM 6491 ^T and Winogradskyella thalassocola KMM 3907 ^T were 80.1, 78.9 and 82.6%, respectively. The digital DNA-DNA hybridization (dDDH) scores were 23.5, 22.9 and 25.7%, respectively. The genomic DNA G + C content was 33.5 mol%. Strain F6397^T contained iso-C_15:0, iso-C_15:1G, iso-C_15:0 3-OH and iso-C_17:0 3-OH as the predominant fatty acid and MK-6 as the predominant menaquinone. The polar lipid profiles contained phosphatidylethanolamine, three unidentified aminolipids and four unidentified lipids. On the basis of the evidence presented in this study, strain F6397^T is considered to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella marina sp. nov. is proposed. The type strain is F6397^T (= KCTC 82422 ^T = MCCC 1H00438^T).

Oceaniferula marina gen.nov., sp.nov., an anti-fluoroquinolone bacterium isolated from marine sediment

A Gram-stain-negative, aerobic, rod-shaped, non-gliding and non-motile bacterium designated as N1E253^T, was isolated from marine sediments collected from the coast of Weihai, PR China. N1E253^T was found to grow at pH 7.0-9.0 (optimum, pH 7.5), 15-37 °C (optimum, 30 °C) in the presence of 1.5-5.0% (w/v) NaCl (optimum, 3.0%). The major polar lipids of strain N1E253^T were phosphatidylethanolamine, diphosphatidylglycerol and one unidentified phospholipid. The sole respiratory quinone was MK-9. The major cellular fatty acids (> 10.0%) were iso-C_{14: 0}, C_{16: 0} and Summed Feature 3 (C_16:1 ω7c and/or C_16:1 ω6c). The result of the 16S rRNA gene sequence analysis confirmed the affiliation of this novel isolate to the family Verrucomicrobiaceae, with Persicirhabdus sediminis KCTC 22039 ^T being its closest relative with 92.1% sequence similarity. Genome sequencing revealed a genome size of 5,073,947 bp, DNA G + C content of 52.0% and two protein-coding genes related to the resistance of fluoroquinolones. Based on physiological, genomic, biochemical and chemotaxonomic characteristics, we propose that strain N1E253^T represents a novel species of a novel genus within the family Verrucomicrobiaceae, for which the name Oceaniferula marina gen. nov., sp. nov. is proposed. The type strain is N1E253^T (= KCTC 72800 ^T = MCCC 1H00405^T).

Description of Lujinxingia vulgaris sp. nov., isolated from coastal sediment via prey-traps

Two Gram-stain negative, facultative anaerobic, oxidase-negative, catalase-positive bacilli, designated as strains TMQ4^T and TMQ2, were isolated from Xiaoshi Island, China, using prey-traps. Growth was observed within the ranges 25-45 °C (optimally at 37 °C), pH 6.5-9.0 (optimally at pH 7.5-8.0) and 1-8% NaCl (optimally at 3-4%, w/v). The draft genome sequences of strains TMQ4^T and TMQ2 contained 184 contigs of 5,609,735 bp with a G+C content of 64.4% and 148 contigs of 5,589,985 bp with a G+C content of 65.0%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that both strains belonged to the genus Lujinxingia with the similarity of 98.9%. The phylogenetic and phylogenomic topologies and analyses demonstrated that both strains clustered together and differentiated from the closest neighbour, Lujinxingia sediminis SEH01^T. Genomic analyses showed that two strains lost the biosynthesis pathway of several chemical compounds. Iso-C_15:0 was contained in the predominant cellular fatty acids in both strains. The major polar lipids of both strains consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and unidentified lipids; and the respiratory quinone was menaquinone MK-7 for both strains. Both strains predated other bacteria, including Owenweeksia hongkongensis JCM 12287^T and Paraliobacillus ryukyuensis DSM 15140^T, and were lured with one prey Acinetobacter baumannii ATCC 19606^T in prey-trap. Combining genomic analyses, two strains had the predatory indices of 2, similar to representative typical bacterial predators. The physiological, biochemical, and phylogenetic properties suggest that the two strains represent a novel species within the genus Lujinxingia. The name Lujinxingia vulgaris sp. nov. is proposed, with strain TMQ4^T (= KCTC 62851^T = MCCC 1H00392^T) as type strain and strain TMQ2 (= KCTC 72,079 = MCCC 1H00381) as reference strain.

Palleronia sediminis sp. nov. and Flavivirga algicola sp. nov., two marine bacteria isolated from offshore areas near Weihai

Two bacterial strains, designated SS33^T and Y03^T, were isolated from marine sediment and marine red alga collected on the coast of Weihai, PR China. Based on the results of 16S rRNA gene sequence analysis, strain SS33^T was found to be closely related to Primorskyibacter marinus PX7^T, Pelagivirga dicentrarchi YLY04^T, Palleronia marisminoris DSM 26347^T and Maribius pontilimi GH1-23^T with 94.8, 94.6, 94.5 and 94.5 % sequence similarity; strain Y03^T was found to be closest to Flavivirga aquimarina EC2D5^T, Flavivirga eckloniae ECD14^T and Flavivirga amylovorans JC2681^T with 96.4, 96.1 and 96.0 % sequence similarity. Strain SS33^T grew at 4-37 °C (optimum, 33 °C), at pH 6.0-9.5 (optimum, pH 7.5-8.0) and in the presence of 0-10 % (w/v) NaCl (optimum, 3.0 %). Chemotaxonomic analysis of strain SS33^T showed that the predominant respiratory quinone was ubiquinone-10. The major fatty acids (>10.0 %) included C_18 : 1  ω7c and C_16 : 0. The major polar lipids included phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid, one unidentified glycolipid, one unidentified polar lipid and two unidentified aminolipids. Strain Y03^T grew at 15-40 °C (optimum, 28 °C), at pH 6.5-8.0 (optimum, pH 7.0) and in the presence of 0.5-9.0 % (w/v) NaCl (optimum, 2.0%). Chemotaxonomic analysis showed that the predominant respiratory quinone was menaquinone-6. The major fatty acids (>10.0 %) included iso-C_15 : 0, iso-C_15 : 1 G, iso-C_17 : 0 3-OH and iso-C_15 : 0 3-OH. The major polar lipids included phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and four unidentified polar lipids. Based on the polyphasic data, strain SS33^T is considered to represent a novel species of the genus Palleronia, for which the name Palleronia sediminis sp. nov. is proposed, with the type strain SS33^T (=KCTC 62986^T=MCCC 1H00387^T). Strain Y03^T is considered to represent a novel species of the genus Flavivirga, for which the name Flavivirga algicola sp. nov. is proposed, with the type strain Y03^T (=KCTC 72001^T=MCCC 1H00386^T).

Sediminihaliea albiluteola gen. nov., sp. nov., a new member of the family Halieaceae, isolated from marine sediment

A Gram-stain-negative, rod-shaped and facultatively aerobic bacterial strain, designated F7430^T, was isolated from coastal sediment collected at Jingzi Wharf in Weihai, PR China. Cells of strain F7430^T were 0.3-0.4 µm wide, 2.0-2.6 µm long, non-flagellated, non-motile and formed pale-beige colonies. Growth was observed at 4-40 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, pH 7.5-8.0) and at NaCl concentrations of 1.0-10.0 % (w/v; optimum, 1.0 %). The sole respiratory quinone of strain F7430^T was ubiquinone 8 and the predominant cellular fatty acids were summed feature 8 (C_18 : 1  ω7c / C_18 : 1  ω6c; 60.7 %), summed feature 3 (C_16 : 1  ω7c/C_16 : 1  ω6c; 30.2 %) and C_15 : 0 iso (13.9 %). The polar lipids of strain F7430^T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid and three unidentified lipids. Results of 16S rRNA gene sequences analyses indicated that this strain belonged to the family Halieaceae and had high sequence similarities to Parahaliea aestuarii JCM 51547^T (95.3 %) and Halioglobus pacificus DSM 27932^T (95.2 %) followed by 92.9-95.0 % sequence similarities to other type species within the aforementioned family. The rpoB gene sequences analyses indicated that the novel strain had the highest sequence similarities to Parahaliea aestuarii JCM 51547^T (82.2 %) and Parahaliea mediterranea DSM 21924^T (82.2 %) followed by 75.2-80.5 % sequence similarities to other type species within this family. Phylogenetic analyses showed that strain F7430^T constituted a monophyletic branch clearly separated from the other genera of family Halieaceae. Whole-genome sequencing of strain F7430^T revealed a 3.3 Mbp genome size with a DNA G+C content of 52.6 mol%. The genome encoded diverse metabolic pathways including the Entner-Doudoroff pathway, assimilatory sulphate reduction and biosynthesis of dTDP-l-rhamnose. Based on results from the current polyphasic study, strain F7430^T is proposed to represent a novel species of a new genus within the family Halieaceae, for which the name Sediminihaliea albiluteola gen. nov., sp. nov. is proposed. The type strain of the type species is F7430^T (=KCTC 72873^T=MCCC 1H00420^T).

Gelidibacter maritimus sp. nov., isolated from marine sediment

A Gram-stain-negative, yellow, strictly aerobic, non-flagellated, gliding, rod-shaped bacterial strain, was isolated from costal sediment, designated as F6074^T. The strain F6074^T grows optimally at 30 °C, pH 7.5, and 3.0% (w/v) NaCl. Cells of strain F6074^T are 0.2-0.5 µm wide and 1.0-2.0 µm long. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain F6074^T belonged to the genus Gelidibacter, with the highest sequence similarity to Gelidibacter japonicus JCM 31967^T (98.0%), followed by G. flavus JCM 31135^T (97.7%), and similarity between strain F6074^T and the type species G. algens DSM 12408^T was 96.0%. Genome sequencing results revealed a genome size of 47,07,621 bp. The DNA G + C content was 37.8 mol%. The ANI and dDDH values between strain F6074^T and G. japonicus JCM 31967^T were 83.9 and 27.8%, the values between strain F6074^T and G. algens DSM 12408^T were 77.5% and 31.5%, and the values between strain F6074^T and G. flavus JCM 31135^T were 84.3 and 27.9%, respectively. The predominant quinone was MK-6 and the major fatty acids were iso-C_15:0, iso-C_15:1G, iso-C_17:0 3-OH, anteiso-C_15:0 and summed feature 3. The polar lipids were consisted of phosphatidylethanolamine (PE), two unidentified aminolipids (AL) and three unidentified lipids (L1, L2, L3). Based on the phenotypic, phylogenetic and chemotaxonomic data, strain F6074^T was considered to represent a novel species of the genus Gelidibacter, for which the name Gelidibacter maritimus sp. nov., is proposed. The type strain is F6074^T (MCCC 1H00427^T = KCTC 72942^T).

Ostreibacterium oceani gen. nov., sp. nov., isolated from oyster, and description of Ostreibacteriaceae fam. nov

A novel Gram-stain-negative, short rod-shaped, facultatively anaerobic, non-motile, non-gliding, oxidase-positive and catalase-negative bacterium, designated ML27^T, was isolated from oyster homogenate in Rushan, Weihai, PR China. Growth occurred at 20-33 °C (optimum, 30 °C), at pH 7.0-9.0 (optimum, pH 7.5-8.0) and in the presence of 1-6 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ML27^T was 90.7 % similar to Suttonella ornithocola DSM 18249^T, 89.2 % to Suttonella indologenes JCM 1478^T and 88.2 % to Cardiobacterium hominis DSM 8339^T; similarities to other species were less than 90 %. The average amino acid identity between strain ML27^T, S. indologenes JCM 1478^T, S. ornithocola DSM 18249^T, C. hominis DSM 8339^T and Dichelobacter nodosus ATCC 25549^T were 46.23, 45.86, 45.54 and 45.84 %, respectively. Phylogenomic tree and phylogenetic analyses based on 16S rRNA gene sequences showed that the isolate formed a novel family-level clade in the order Cardiobacteriales. The sole respiratory quinone was ubiquinone-7 (Q-7). The dominant cellular fatty acids were summed feature 8 (C_18 : 1 ω7c/C_18 : 1 ω6c; 46.3 %), C_16 : 0 (17.8 %) and summed feature 3 (C_16 : 1 ω7c/C_16 : 1 ω6c; 13.5 %). The DNA G+C content of strain ML27^T was 45.6 mol%. Polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one unidentified lipid. Comparative analyses of 16S rRNA gene sequences, genomic distinctiveness and characterization indicated that strain ML27^T represents a novel species of a new genus within a novel family of the order Cardiobacteriales, for which the name Ostreibacterium oceani gen. nov., sp. nov. is proposed. The type strain of Ostreibacterium oceani is ML27^T (=MCCC 1H00372^T=KCTC 72155^T). In addition, a novel family, Ostreibacteriaceae fam. nov., is proposed to accommodate the genus Ostreibacterium.

Salibaculum halophilum gen. nov., sp. nov. and Salibaculum griseiflavum sp. nov., in the family Rhodobacteraceae

Two Gram-stain-negative, moderately halophilic, non-motile, rod-shaped, pale yellow, and aerobic strains, designated WDS1C4^T and WDS4C29^T, were isolated from a marine solar saltern in Weihai, Shandong Province, PR China. Growth of strain WDS1C4^T occurred at 10-45 °C (optimum, 37 °C), with 4-16 % (w/v) NaCl (optimum, 8 %) and at pH 6.5-9.0 (optimum, pH 7.5). Growth of strain WDS4C29^T occurred at 10-45 °C (optimum, 40 °C), with 2-18 % (w/v) NaCl (optimum, 6 %) and at pH 6.5-9.0 (optimum, pH 7.5). Q-10 was the sole respiratory quinone of the two strains. The major polar lipids of strains WDS1C4^T and WDS4C29^T were phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The major cellular fatty acid in strains WDS1C4^T and WDS4C29^T was C_18 : 1  ω7c, and the genomic DNA G+C contents of strains WDS1C4^T and WDS4C29^T were 67.6 and 63.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains WDS1C4^T and WDS4C29^T were members of the family Rhodobacteraceae and showed 94.3 and 95.3 % similarities to their closest relative, Celeribacter indicus, respectively. The similarity between WDS1C4^T and WDS4C29^T was 97.3 %. Differential phenotypic and genotypic characteristics of the two isolates from recognized genera showed that the two strains should be classified as representing two novel species in a new genus for which the names Salibaculum halophilum gen. nov., sp. nov. (type species, type strain WDS1C4^T=MCCC 1H00179^T=KCTC 52542^T) and Salibaculum griseiflavum sp. nov. (WDS4C29^T=MCCC 1H00175^T=KCTC 52541^T) are proposed.

Pontibaca salina sp. nov., isolated from marine sediment

A Gram-stain-negative, oval or short rod-shaped, non-motile, aerobic bacterium, designated strain S1109L^T, was isolated from a marine sediment in Weihai, PR China. Cells were oxidase positive and catalase positive. Growth of strain S1109L^T occurred at 10-40 °C (optimum, 30-33 °C), pH 6.5-10.0 (optimum, 7.0-8.0) and in the presence of 1-21% (optimum, 4-6%) (w/v) NaCl. 16S rRNA gene sequence phylogeny indicated that strain S1109L^T was associated with the genus Pontibaca of the family Rhodobacteraceae because it showed the highest sequence similarity to Pontibaca methylaminivorans KCTC 22497^T (97.5%). The average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) scores between strain S1109L^T and Pontibaca methylaminivorans KCTC 22497^T were 74.6% and 18.7%. The major cellular fatty acids of strain S1109L^T were C_19:0 cyclo ω8c and C_18:1 ω7c. The polar lipids profiles of strain S1109L^T were phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and two unidentified lipids. Strain S1109L^T contained ubiquinone-10 as the major respiratory quinone. The genomic DNA G + C content was 55.9 mol%. On the basis of the evidence presented in this study, strain S1109L^T is considered to represent a novel species of the genus Pontibaca, for which the name Pontibaca salina sp. nov. is proposed. The type strain of is S1109L^T (= KCTC 82411^T = MCCC 1H00441^T).

Stappia albiluteola sp. nov., isolated from marine sediment

A Gram-stain negative, rod-shaped, facultatively aerobic, pale-beige-coloured bacterial strain, designated F7233^T, was isolated from coastal sediment sampled at Jingzi Bay, Weihai, PR China. Cells of strain F7233^T were 0.3-0.4 µm wide, 1.2-1.4 µm wide long, non-spore-forming and motile with one flagellum. Optimum growth occurred at 30 °C, with 1.0 % (w/v) NaCl and at pH 6.5-7.0. Positive for nitrate reduction, hydrolysis of Tweens and oxidase activity. The sole respiratory quinone of strain F7233^T was ubiquinone-10 and the predominant cellular fatty acid was summed feature 8 (C_18 : 1  ω7c/C_18 : 1  ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and one unidentified aminophospholipid. The G+C content of the chromosomal DNA was 63.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence revealed that the newly isolate belonged to the genus Stappia, with 96.8 % sequence similarity to Stappia indica MCCC 1A01226^T, 96.1 % similarity to Stappia stellulata JCM 20692^T and 95.5% similarity to Stappia taiwanensis CC-SPIO-10-1^T. On the basis of phylogenetic, phenotypic and chemotaxonomic data, it is considered that strain F7233^T should represent a novel species within the genus Stappia, for which the name Stappia albiluteola sp. nov. is proposed. The type strain is F7233^T (=MCCC 1H00419^T=KCTC 72859^T).

Croceimicrobium hydrocarbonivorans gen. nov., sp. nov., a novel marine bacterium isolated from a bacterial consortium that degrades polyethylene terephthalate

A novel Gram-stain-negative, aerobic, gliding, rod-shaped and carotenoid-pigmented bacterium, designated A20-9^T, was isolated from a microbial consortium of polyethylene terephthalate enriched from a deep-sea sediment sample from the Western Pacific. Growth was observed at salinities of 1-8 %, at pH 6.5-8 and at temperatures of 10-40 °C. The results of phylogenetic analyses based on the genome indicated that A20-9^T formed a monophyletic branch affiliated to the family Schleiferiaceae, and the 16S rRNA gene sequences exhibited the maximum sequence similarity of 93.8 % with Owenweeksia hongkongensis DSM 17368^T, followed by similarities of 90.4, 90.1 and 88.8 % with Phaeocystidibacter luteus MCCC 1F01079^T, Vicingus serpentipes DSM 103558^T and Salibacter halophilus MCCC 1K02288^T, respectively. Its complete genome size was 4 035 598 bp, the genomic DNA G+C content was 43.2 mol%. Whole genome comparisons indicated that A20-9^T and O. hongkongensis DSM 17368^T shared 67.8 % average nucleotide identity, 62.7 % average amino acid identity value, 46.6% of conserved proteins and 17.8 % digital DNA-DNA hybridization identity. A20-9^T contained MK-7 as the major respiratory quinone. Its major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phospatidylcholine; and the major fatty acids were iso-C_15 : 0 (37.5 %), iso-C_16 : 0 3-OH (12.4 %), and summed feature 3 (C_16 : 1ω7c /C1_6 : 1ω6c, 11.6 %). Combining the genotypic and phenotypic data, A20-9^T could be distinguished from the members of other genera within the family Schleiferiaceae and represents a novel genus, for which the name Croceimicrobium hydrocarbonivorans gen. nov., sp. nov. is proposed. The type strain is A20-9^T (=MCCC 1A17358^T =KCTC 72878^T).

Moheibacter lacus sp. nov., Isolated from Freshwater Lake Sediment

A Gram-stain-negative, yellow-pigmented, rod-shaped, strictly aerobic, non-motile bacterium, designated BDHS18^T, was isolated from the sediment of the Hasuhai Lake, China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that this strain belongs to the genus Moheibacter in the family Flavobacteriaceae and its closest relative was Moheibacter sediminis JCM 19634^T (96.0%), followed by Moheibacter stercoris DSM 29388^T (95.3%). Cells of strain BDHS18^T were catalase-positive and oxidase-negative. Strain BDHS18^T was found to grow optimally at 28-33 ℃, pH 7.5-8.0, and in the presence of approximately 1.0% (w/v) NaCl. Major cellular fatty acids were iso-C_15:0, iso-C_17:0 3-OH, Summed feature 4 and Summed feature 9. The predominant respiratory quinone was MK-6. The predominant polar lipids in strain BDHS18^T were phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G + C content was 36.9 mol%. According to the phylogenetic analysis, physiological and phenotypic characteristics, strain BDHS18^T represents a novel species of the genus Moheibacter, for which the name Moheibacter lacus sp. nov. is proposed. The type strain is BDHS18^T (= KCTC 72160^T = MCCC 1H00369^T).

Bioprospecting of Soil-Derived Actinobacteria Along the Alar-Hotan Desert Highway in the Taklamakan Desert

Taklamakan desert is known as the largest dunefield in China and as the second largest shifting sand desert in the world. Although with long history and glorious culture, the Taklamakan desert remains largely unexplored and numerous microorganisms have not been harvested in culture or taxonomically identified yet. The main objective of this study is to explore the diversity, novelty, and pharmacological potential of the cultivable actinomycetes from soil samples at various sites along the Alar-Hotan desert highway in the Taklamakan desert. A total of 590 actinobacterial strains were recovered by the culture-dependent approach. Phylogenetic analysis based on 16S ribosomal RNA (rRNA) gene sequences unveiled a significant level of actinobacterial diversity with 55 genera distributed in 27 families of 12 orders. Thirty-six strains showed relatively low 16S rRNA similarities (<98.65%) with validly described species, among which four strains had already been characterized as novel taxa by our previous research. One hundred and forty-six actinobacterial isolates were selected as representatives to evaluate the antibacterial activities and mechanism of action by the paper-disk diffusion method and a double fluorescent protein reporter "pDualrep2" system, respectively. A total of 61 isolates exhibited antagonistic activity against the tested "ESKAPE" pathogens, among which seven strains could produce bioactive metabolites either to be able to block translation machinery or to induce SOS-response in the pDualrep2 system. Notably, Saccharothrix sp. 16Sb2-4, harboring a promising antibacterial potential with the mechanism of interfering with protein translation, was analyzed in detail to gain deeper insights into its bioactive metabolites. Through ultra-performance liquid chromatography (UPLC)-quadrupole time-of-flight (QToF)-MS/MS based molecular networking analysis and databases identification, four families of compounds (1-16) were putatively identified. Subsequent bioassay-guided separation resulted in purification of four 16-membered macrolide antibiotics, aldgamycin H (8), aldgamycin K (9), aldgamycin G (10), and swalpamycin B (11), and their structures were elucidated by HR-electrospray ionization source (ESI)-MS and NMR spectroscopy. All compounds 8-11 displayed antibacterial activities by inhibiting protein synthesis in the pDualrep2 system. In conclusion, this work demonstrates that Taklamakan desert is a potentially unique reservoir of versatile actinobacteria, which can be a promising source for discovery of novel species and diverse bioactive compounds.

Planococcus maritimus ML1206 Isolated from Wild Oysters Enhances the Survival of Caenorhabditis elegans against Vibrio anguillarum

With the widespread occurrence of aquaculture diseases and the broad application of antibiotics, drug-resistant pathogens have increasingly affected aquatic animals’ health. Marine probiotics, which live under high pressure in a saltwater environment, show high potential as a substitute for antibiotics in the field of aquatic disease control. In this study, twenty strains of non-hemolytic bacteria were isolated from the intestine of wild oysters and perch, and a model of Caenorhabditis elegans infected by Vibrio anguillarum was established. Based on the model, ML1206, which showed a 99% similarity of 16S rRNA sequence to Planococcus maritimus, was selected as a potential marine probiotic, with strong antibacterial capabilities and great acid and bile salt tolerance, to protect Caenorhabditis elegans from being damaged by Vibrio anguillarum. Combined with plate counting and transmission electron microscopy, it was found that strain ML1206 could significantly inhibit Vibrio anguillarum colonization in the intestinal tract of Caenorhabditis elegans. Acute oral toxicity tests in mice showed that ML1206 was safe and non-toxic. The real-time qPCR results showed a higher expression level of genes related to the antibacterial peptide (ilys-3) and detoxification (ugt-22, cyp-35A3, and cyp-14A3) in the group of Caenorhabditis elegans protected by ML1206 compared to the control group. It is speculated that ML1206, as a potential probiotic, may inhibit the infection caused by Vibrio anguillarum through stimulating Caenorhabditis elegans to secrete antibacterial effectors and detoxification proteins. This paper provides a new direction for screening marine probiotics and an experimental basis to support the potential application of ML1206 as a marine probiotic in aquaculture.

Sulfitobacter algicola sp. nov., isolated from green algae

A novel Gram-stain-negative, aerobic, non-flagellated, non-motile, oval-rod-shaped and light pink to light tawny-pigmented bacterial strain (designated 1151^T) were isolated from marine green algae obtained from the coastal seawater of Weihai, China. Strain 1151^T was found to grow at 15-37 °C (optimum, 33 °C), pH 7.0-9.5 (optimum, 7.5-8.5) and in the presence of 1-6% (w/v) NaCl (optimum, 3%). Cells were oxidase-positive and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 1151^T was a member of the genus Sulfitobacter and exhibited the hightest sequence similarity to Sulfitobacter indolifex DSM 14862^T (96.6%), followed by the sequence similarity to Sulfitobacter aestuarii hydD52^T (96.5%) and Sulfitobacter profundi SAORIC-263^T (96.5%). The average nucleotide identity and digital DDH values between strain 1151^T and Sulfitobacter indolifex DSM 14862^T were 69.9% and 20.9%, respectively. The average amino acid identity between strain 1151^T and Sulfitobacter pontiacus DSM 10014^T (type strain of the type species) was 62.3%. Q-10 was detected as the sole respiratory quinone. The dominant cellular fatty acids were sum feature 8 (C_{18: 1}ω7c; 44.1%), C_{20: 1}ω7c (29.7%) and C_{18: 0} (11.7%). The DNA G + C content of strain 1151^T was 51.8 mol%. The polar lipids included phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and three unidentified lipids (L1, L2 and L3). Based on the phylogenetic and phenotypic characteristics, strain 1151^T is considered to represent a novel species of the genus Sulfitobacter, for which the name Sulfitobacter algicola sp. nov. is proposed. The type strain is 1151^T (= KCTC 72513^T = MCCC 1H00384^T).

Propylenella binzhouense gen. nov., sp. nov. isolated from activated sludge, and proposal of Propylenellaceae fam. nov

A Gram-stain-negative, non-spore-forming, non-motile, short-rod-shaped, and aerobic bacterial strain (designated L72^T) was isolated from propylene oxide saponification wastewater activated sludge obtained from a wastewater treatment facility in Binzhou (Shandong Province, PR China). Strain L72^T grew between 25 and 40 °C (optimum growth at 30 °C). The pH range for growth was between 6.0 and 8.0 (optimum growth at pH 7.0). The range of NaCl concentrations for the growth of strain L72^T was 0-3.0 % (w/v), with optimum growth at 1.0-2.0 % (w/v). The major cellular fatty acids of strain L72^T were C_19:0cyclo ω8c, C_18:1ω7c, iso-C_15:0, and anteiso-C_15:0. Strain L72^T contained Q-10 as the predominant respiratory quinone. The polar lipid profile was composed of Phosphatidylcholine, Glycolipid, Aminophospholipid, Phosphatidylethanolamine, Phosphatidylserine, Phosphatidyldimethylethanolamine, one unknown lipid (L) and two unidentified Phospholipids (PL). Genome sequencing revealed a genome size of 4,703,686 bp and a G + C content of 69.0 mol%. The 16S rRNA gene sequence similarities of strain L72^T with other species were less than 94%. Phylogenetic analyses based on 16S rRNA gene sequences and genome data, revealed that strain L72^T formed a distinct phylogenetic lineage within the order Hyphomicrobiales, separating them from members of all families. Strain L72^T showed 70.7% average nucleotide identity and 18.6% digital DNA-DNA hybridization identity with the closely related species Rhodoligotrophos defluvii. Based on the phenotypic, phylogenetic and chemotaxonomic data, a new family Propylenellaceae fam. nov. comprising the genus Propylenella gen. nov. and species Propylenella binzhouense sp. nov. is proposed. The type strain is L72^T (=  CCTCC AB 2019081^T  =  KCTC 72254^T).

Oceanipulchritudo coccoides gen. nov., sp. nov., isolated from marine sediment within the family Puniceicoccaceae

A Gram-stain-negative, aerobic coccus, designated CK1056^T, was isolated from coastal sediment of Xiaoshi Island, Weihai, PR China. Strain CK1056^T was found to grow at 15-37 °C (optimum, 30 °C), with 0.5-6.5 % (w/v) NaCl (optimum, 3.5 %) and displayed alkaliphilic growth within the pH range of pH 6.5-10.0 (optimum, pH 8.0). The major fatty acids identified were iso-C_15 : 0 and summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c). The main polar lipids consisted of aminophosphoglycolipid and phosphatidylethanolamine. The predominant respiratory quinone was MK-7. The G+C content of the genomic DNA was 54.0 mol%. The result of the 16S rRNA gene sequence analysis confirmed the affiliation of this micro-organism to the family Puniceicoccaceae, with Coraliomargarita akajimensis KCTC 12865^T as its closest relative with only 88.0 % sequence similarity. From the taxonomic data obtained in this study, we propose that the new marine isolate be placed into a novel species within a novel genus in the family Puniceicoccaceae, phylum Verrucomicrobia, for which the name Oceanipulchritudo coccoides gen. nov., sp. nov. is proposed. The type strain is CK1056^T (=KCTC 72798^T=MCCC 1H00425^T).

Algibacillus agarilyticus gen. nov., sp. nov., isolated from the surface of the red algae Gelidium amansii

A novel Gram-stain-negative, strictly aerobic, coccoid and agar-hydrolysing bacterium, designated RQJ05^T, was isolated from the marine red algae Gelidium amansii collected from the coastal area of Rizhao, PR China. Cells of strain RQJ05^T were approximately 0.8-1.0×1.3-3.0 µm in size and motile by means of a polar flagellum. Growth occurred at 4-33 °C (optimum, 25-30 °C), pH 7.0-8.5 (optimum, pH 7.5-8.0) and in the presence of 1.0-7.0 % (w/v) NaCl (optimum, 2.0-3.0 %). Strain RQJ05^T showed oxidase-positive and catalase-negative activities. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain RQJ05^T formed a phylogenetic lineage with members of the family Alteromonadaceae and exhibited 16S rRNA gene sequence similarities of 92.6, 91.3, 90.2 and 90.1 % to Catenovulum maritimum Q1^T, Catenovulum agarivorans YM01^T, Paraphotobacterium marinum NSCS20N07D^T and Algicola sagamiensis B-10-31^T, respectively. The major cellular fatty acids of strain RQJ05^T were summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c), C_16 : 0 and summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c). The major polar lipids of strain RQJ05^T were phosphatidylethanolamine, phosphatidylglycerol and two aminophospholipids. Strain RQJ05^T contained Q-8 as the major respiratory quinone. The genomic DNA G+C content was 39.0 mol%. On the basis of genotypic, phenotypic and phylogenetic evidence, strain RQJ05^T is presented as a representative of a novel species in a new genus, for which the name Algibacillus agarilyticus gen. nov., sp. nov. is proposed. The type strain is RQJ05^T (=KCTC 62846^T=MCCC 1H00352^T).

Motilibacter deserti sp. nov. and Motilibacter aurantiacus sp. nov., two novel actinobacteria isolated from soil of Cholistan Desert and emended description of the genus Motilibacter

Two novel actinobacterial strains, designated as E257^T and K478^T, were isolated from hyper-arid soil samples collected in Cholistan Desert, Pakistan. Comparative analysis of 16S rRNA genes showed that strains E257^T and K478^T were assigned to the genus Motilibacter, being their closest relative M. rhizosphaerae RS-16^T with 97.3% and 96.7% similarities, respectively. The sequence similarity between strain E257^T and K478^T was 98.9%. Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on multiple genes of conserved core proteins exhibited that these two strains belonged to the genus Motilibacter and formed a robust cluster separated from the two type species of the genus Motilibacter. Average Nucleotide Identity (ANI), Average Amino acid Identity (AAI), digital DNA-DNA hybridization (dDDH) values and Percentage of Conserved Proteins (POCP) calculated from the complete genome sequences indicated strains E257^T and K478^T were assigned into genus Motilibacter but clearly separated from each other and from the other species of the genus Motilibacter with values below the thresholds for species delineation. The two isolates were found to have chemotaxonomic, cultural and morphological properties consistent with their classification in the genus Motilibacter and also confirmed the differentiation from their closest species. The obtained results demonstrated that strains E257^T and K478^T represent two novel species of the genus Motilibacter, for which the names Motilibacter desertisp. nov. (type strain E257^T = JCM 33651^T = CGMCC 1.17159^T) and Motilibacter aurantiacus sp. nov. (type strain K478^T =JCM 33652^T =CGMCC 1.17229^T) are proposed.

Aeromicrobium piscarium sp. nov., isolated from the intestine of Collichthys lucidus

A Gram-stain-positive, rod-shaped, whitesmoke-coloured and aerobic bacterium, designated strain Co35T, was isolated from the intestine of Collichthys lucidus collected from the Jiangmen Guangdong Chinese White Dolphin Provincial Nature Reserve. Strain Co35T was able to grow at 15–35 °C (optimal 28 °C), at pH 7.0–8.5 (optimal 8.0) and with 0–9 % (w/v) NaCl (optimal 0.5–1 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Co35T was a member of the genus Aeromicrobium within the family Nocardioidaceae . The genomic DNA G+C content of strain Co35T was 68.4 mol%. Chemotaxonomic analysis showed that the sole respiratory quinone was menaquinone 9 (MK-9), and the major fatty acids included 10-methyl C18 : 0. The polar lipids were found to consist of phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), two unidentified phospholipids (PL1–2) and two unidentified glycolipids (GL1–2). On the basis of its phylogenetic, phenotypic, chemotaxonomic, genotypic and genomic characteristics presented in this study, strain Co35T represents a novel species in the genus Aeromicrobium , for which the name Aeromicrobium piscarium sp. nov. is proposed. The type strain is Co35T (=KCTC 49280T=MCCC 1K03754T).

Roseomonas bella sp. nov., isolated from lake sediment

A Gram-stain-negative, non-motile, coccus-shaped, catalase- and oxidase-positive, facultatively anaerobic and pink-pigmented bacterium, designated strain CQN31^T, was isolated from sediment of Changqiaohai Lake, Yunnan Province, China. Growth occurred at 4-45 °C (optimum, 37 °C), at pH 6.5-9.5 (optimum, pH 8.0) and with 0-1 % (w/v) NaCl (optimum, 0 %). C_18 : 1 ω7c/C_18 : 1 ω6c and C_16 : 0 were the predominant fatty acids. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidyldimethylethanolamine (PME) and one unidentified aminolipid (AL) were the major polar lipids. The G+C content of the genomic DNA was 71.5 %. 16S rRNA gene sequence comparisons indicated that strain CQN31^T shared 96.8 % similarity with Roseomonas wooponensis JCM 19527^T and 95.9 % with R. terricola EM0302^T. Digital DNA-DNA hybridization values between strain CQN31^T and Roseomonas stagni DSM 19981^T, R. rosea DSM 14916^T and R. mucosa NCTC 13291^T were 21.0, 19.4 and 19.8 %, respectively. Average amino acid identity and average nucleotide identity values between strain CQN31^T and R. stagni DSM 19981^T, R. rosea DSM 14916^T and R. mucosa NCTC 13291^T were 73.7, 63.4 and 61.9 %, and 79.2, 77.1 and 77.5%, respectively. Distinct morphological, physiological and genotypic differences from previously described taxa support the classification of strain CQN31^T as a representative of a novel species in the genus Roseomonas, for which the name Roseomonas bella sp. nov. is proposed. The type strain is CQN31^T (=KCTC 62447^T=MCCC 1H00309^T).

Algibacter marinivivus sp. nov., isolated from the surface of a marine red alga

A Gram-stain-negative, non-flagellated bacterium, designated ZY111T, was isolated from the surface of a marine red alga, which was collected from the coast in Weihai, Shandong Province, PR China. Strain ZY111T exhibited growth at 4–37 °C (optimum, 25–28 °C) in the presence of 0–8.0 % (w/v) NaCl (optimum, 2.0–4.0% NaCl) and at pH 6.5–9.5 (optimum, pH 7.0–8.0). The 16S rRNA gene sequence analysis revealed that strain ZY111T belonged to the genus Algibacter , with Algibacter amylolyticus DSM 29199T as its closest relative (97.7 % similarity). The averagenucleotide identity value of strain ZY111T with A. amylolyticus DSM 29199T was 79.03 %. The digitalDNA–DNA hybridization value of strain ZY111T with A. amylolyticus DSM 29199T was 22.40 %. The dominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The sole respiratory quinone was determined to be menaquinone-6. The polar lipid profile of strain ZY111T consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. The G+C content was 31.9 mol%. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain ZY111T represents a novel species of the genus Algibacter , for which the name Algibacter marinivivus sp. nov. is proposed. The type strain is ZY111T (=KCTC 62373T=MCCC 1H00295T).