Flavobacterium sangjuense sp. nov. isolated from sediment Abstract A yellow-pigmented bacterial strain, GS03T, was isolated from sediment in a branch of the Nackdong River in Sangju, Korea. Cells were observed to be Gram-negative, aerobic and rod-shaped with gliding motility, and to be positive for catalase and oxidase. Growth was found to occur at 4–30 °C (optimum 25 °C), at pH 7.0–8.5 (optimum pH 7.5) and at NaCl 0% (optimum NaCl 0%, w/v). The major cellular fatty acids (> 10% of the total) were identified as iso C15:0, iso C15:1 G, C15:1ω6c, iso C15: 0 3-OH and iso C17: 0 3-OH. The major respiratory quinone was found to be menaquinone MK-6. The genome sequence of GS03T is 3.1 Mb with G+C content of 36.1 mol%. The major polar lipids of the isolate were identified as phosphatidylethanolamine, three unidentified aminolipids, two unidentified phospholipids, an unidentified lipid and an unidentified aminophospholipid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GS03T clusters with Flavobacterium paronense KNUS1TT, with similarity of 96.8%. The phenotypic, phylogenetic, and chemotaxonomic characteristics indicate that strain GS03T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium sangjuense sp. nov. is proposed. The type strain is GS03T (= FBCC 502459T = KCTC 62568T = JCM 32764T).

Microvirga calopogonii sp. nov., a novel alphaproteobacterium isolated from a root nodule of Calopogonium mucunoides in Southwest China Abstract In this study, a Gram-negative, rod-shaped, and non-spore-forming bacterium, which was designated as strain CCBUA 65841T, was isolated from a root nodule of Calopogonium mucunoides grown in Yunan Province of China. The sequence alignment results of 16S rRNA and four housekeeping genes (including gyrB, recA, dnaK and rpoB) indicated the isolated strain is a member of the genus Microvirga, closely related to Microvirga lotononidis WSM3557T. In addition, results of genome average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) had revealed the lower values (ANI ≤ 88.72%, dDDH ≤ 39.5%) between strain CCABU 65841T and other related Microvirga species. The genome of the novel strain exhibits a G + C content of 64.48% and contains 7296 protein-coding genes and 93 RNA genes. The major polar lipids were found to be phosphatidylcholine and phosphatidylethanolamine. The predominant cellar fatty acids were identified to be C16:0, C18:0, C19:0 cyclo ω8c, summed feature 2, summed feature 3 and summed feature 8. Moreover, menaquinone 8 (MK-8) was detected to be the predominant quinone. Based on the phylogenetic and phenotypic dissimilarity, a novel species Microvirga calopogonii sp. nov. is proposed with the type strain CCABU 65841T (= LMG 25488 T = HAMBI 3033T).

Actinobacillus seminis GroEL-homologous protein agglutinates sheep erythrocytes Abstract Actinobacillus seminis, a commensal of ovine and caprine reproductive organs, is able to induce epididymitis in the small ruminants that it infects. In this work, we characterised two protein bands of approximately 150 kDa and 65 kDa. These proteins cross-reacted with a polyclonal serum against Gallibacterium anatis hemagglutinin and with a polyclonal serum from sheep with epididymitis, indicating that the proteins are expressed in vivo; the two proteins also interacted with biotin-labeled sheep fibrinogen and fibronectin, suggesting that they may function as adhesins. The participation of these proteins as adhesins was confirmed by a cultured human bladder cell-A. seminis adhesion assay and adherence inhibition by preincubation of A. seminis with polyclonal antiserum to the 150 kDa protein. Both proteins presented sequence identity with an A. seminis GroEL protein by mass spectrometry analysis and agglutinated glutaraldehyde-fixed sheep red blood cells. Immunogold labeling was observed by transmission electron microscopy on bacterial cells that were negatively stained, and a peroxidase reaction was detected in A. seminis biofilms, when an anti-A. seminis 150 kDa protein serum was used, indicating the presence of this protein on the surface of A. seminis and in biofilms. The A. seminis GroEL-homologue is a multifunctional protein that likely acts as a hemagglutinin.

Cellulomonas aurantiaca sp. nov., isolated from a soil sample from a tangerine field Abstract A Gram-stain positive, facultatively aerobic, motile and rod-shaped bacterial strain, designated THG-SMD2.3T, was isolated from a soil sample collected in a tangerine field, Republic of Korea. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Cellulomonas and to be closely related to Cellulomonas fimi ATCC 484T (98.5%), Cellulomonas biazotea DSM 20112T (98.3%), Cellulomonas chitinilytica X.bu-bT (98.0%), Cellulomonas xylanilytica XIL11T (97.2%), Cellulomonas humilata ATCC 25174T (97.1%) and Cellulomonas composti TR7-06T (97.0%). The 16S rRNA gene sequence similarities with other current species of the genus Cellulomonas were in the range 95.4–96.6%. Catalase and oxidase tests were found to be positive. The DNA G+C content was determined to be 73.0 mol%. DNA-DNA hybridization values between strain THG-SMD2.3T and C. fimi ATCC 484T, C. biazotea DSM 20112T, C. chitinilytica X.bu-bT, C. xylanilytica XIL11T, C. humilata ATCC 25174T and C. composti TR7-06T were 58.1 ± 1.6%, 56.7 ± 0.8%, 30.3 ± 1.6%, 22.8 ± 1.6%, 19.9 ± 1.6%, and 13.5 ± 3.0%, respectively. Strain THG-SMD2.3T was also found to be able to grow at 20–42 °C, at 0–3% NaCl and at pH 5.5–10. The major fatty acids were identified as anteiso-C15:0, iso-C15:0, anteiso-C17:0 and iso-C14:0. The predominant menaquinone was identified as tetrahydrogenated menaquinones with nine isoprene units [MK-9(H4)]. The polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and two unidentified phospholipids. Based on these phenotypic, genotypic and phylogenetic characterisations strain THG-SMD2.3T (= KACC 19341T = CGMCC 1.16303T) is concluded to represent a novel species of the genus Cellulomonas, for which the name Cellulomonas aurantiaca sp. nov. is proposed.

Corallincola luteus sp. nov., a marine bacterium isolated from surface sediment of Bohai Sea of China Abstract A novel Gram-stain negative, strictly aerobic, rod-shaped motile bacterium with a single flagellum, designated strain DASS28T, was isolated from surface sediment of Bohai Sea in China. Growth occurred in the presence of 1.0–4.0% NaCl (w/v, optimum 2.0%), at 10–37 °C (optimum 20 °C) on the Marine agar 2216E and pH 6.0–10.0 (optimum pH 8.0). The major fatty acids (> 10% of total fatty acids) were summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1ω7c. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminolipid and two unidentified polar lipids. The major respiratory quinone was ubiquinone-8 (Q-8). The genomic DNA G + C content calculated from the genome sequence of strain DASS28T was 48.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain DASS28T belongs to the genus Corallincola and shows high 16S rRNA gene sequence similarity of 96.7% to Corallincola platygyrae JLT 2006T (= JCM18796T = CGMCC 1.10992T). On the basis of the polyphasic evidence, strain DASS28T is considered to represent a novel species in the genus Corallincola, for which the name Corallincola luteus sp. nov. is proposed. The type strain is DASS28T (= KCTC 52376T = MCCC 1K03208T).

Bioinformatic analyses of a potential Salmonella - virus - FelixO1 biocontrol phage BPS15S6 and the characterisation and anti-Enterobacteriaceae-pathogen activity of its endolysin LyS15S6 Abstract Foodborne Enterobacteriaceae pathogens, especially Salmonella, still seriously threaten food safety. To establish a foundation for further developing phage- and endolysin-based methods combating these pathogens, in this study, the newly isolated Salmonella-virus-FelixO1 phage BPS15S6 for biocontrol purposes was characterised by genomic bioinformatic analysis, and then its endolysin LyS15S6 was obtained using a prokaryotic expression system, characterised in vitro and evaluated in the antibacterial efficacy. It was shown that BPS15S6 had an 87,609-bp genome with 130 open reading frames and does not appear to carry known lysogeny-associated genes and other damaging genetic determinants and is unlikely to perform generalised transduction. Furthermore, LyS15S6 was determined to possess the high enzymatic activity of 1,001,000 U mg−1 and the broad spectrum of lysing 56 tested Gram-negative strains. The assays of thermostability and optimum pH revealed that LyS15S6 was stable up to 40 °C and more active at pH 7. Notably, we demonstrate that edible ε-poly-l-lysine (EPL) can be used as an outer-membrane permeabiliser to improve the antibacterial performance of endolysins. When combined with 1 μg ml−1 EPL, 2 μM LyS15S6 could cause 3–4 log viable cell reductions of the three tested Enterobacteriaceae pathogens in vitro after 2 h of reaction at 25 °C and 2.56 and 3.14 log reductions of Salmonella ATCC13076 after 15 min of reaction at 25 °C and 2 h of reaction at 8 °C respectively. A new strategy, the combined application of endolysins and edible EPL for combating Enterobacteriaceae pathogens in food, is thus presented in this work.

Co-inoculation of different antagonists can enhance the biocontrol activity against Rhizoctonia solani in tomato Abstract Biological control by using microbial inoculants is adopted as the best alternative to chemical pesticides to manage plant diseases. In the present study, a microbial consortia based management strategy involving the microbes Bacillus velezensis MB101 (BV), Streptomyces atrovirens N23 (SA) and Trichoderma lixii NAIMCC-F-01760 (TL), was evaluated for the management of Rhizoctonia solani (RS), the causal agent of tomato root rot. The efficacy of these microbial inoculants was evaluated in glasshouse and field experiments. Plant defense-related enzymes were assayed in the glasshouse, and biocontrol effect was evaluated in the field with RS infected soil. In the glasshouse experiment, co-inoculated SA + TL treated plants showed maximum disease resistance in comparison to control. Also, the plant defense-related enzymes such as chitinase, β-1,3-glucanase, peroxidases, polyphenol oxidase, and phenylalanine ammonia lyase were increased in this treatment. Furthermore, three application methods were assessed in the field, and SA + TL showed maximum disease reduction (76%) by the dual application. Based on glasshouse and field study results, it was concluded that co-inoculation of SA + TL activated plant defense against RS as compared to the individual microbes, and co-inoculation could be a new effective strategy to manage the root rot pathogen in an eco-compatible manner.

Pontibacter oryzae sp. nov., a carotenoid-producing species isolated from a rice paddy field Abstract A taxonomic study using a polyphasic approach was performed on a Gram-stain negative, red-pink, aerobic, non-motile, asporogenous, rod-shaped bacterium, designated strain KIRANT, isolated from soil collected from a rice paddy field. The 16S rRNA gene sequence analysis showed that strain KIRANT is phylogenetically related to Pontibacter actiniarum KMM 6156T, Pontibacter korlensis X14-1T, Pontibacter odishensis JC130T, Pontibacter litorisediminis YKTF-7T and Pontibacter aurantiacus NP1T (97.6, 97.5, 97.3, 97.3 and 96.7% sequence similarity, respectively). The major fatty acids of strain KIRANT were identified as iso-C15:0, iso-C15:0 3-OH and summed feature 4. The predominant menaquinone was identified as MK-7. The polar lipid profile was found to consist of phosphatidylethanolamine, four unidentified phospholipids, an unidentified glycolipid, an unidentified aminolipid and four unidentified lipids. The genome of strain KIRANT has a G + C content of 48.3 mol%. The in silico DNA–DNA hybridization and average nucleotide identity values between strain KIRANT and the closely related strains P. actiniarum KMM 6156T and P. korlensis X14-1T were 21.2%/21.8% and 76.4%/75.1%, respectively. On the basis of the data from phenotypic tests and genotypic differences between strain KIRANT and its close phylogenetic relatives, strain KIRANT is concluded to represent a new species belonging to the genus Pontibacter, for which the name Pontibacter oryzae sp. nov. is proposed. The type strain is KIRANT (= KACC 19815T = JCM 32880T).

Vibrio profundi sp. nov., isolated from a deep-sea seamount Abstract A Gram-stain negative, rod-shaped, facultative anaerobic, motile bacterial strain, designated TP187T, was isolated from a seamount near the Yap Trench in the tropical western Pacific. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain TP187T is related to members of the genus Vibrio and has high 16S rRNA gene sequence similarity with the type strains of Vibrio chagasii (97.3%) and Vibrio gallaecicus (97.1%). Sequence similarities to all other type strains of current species of the genus Vibrio were below 97%. The polar lipids profile was found to contain diphosphatidylglycerol, phosphatidylglycerol, an aminophospholipid, two aminolipids, four phospholipids and eleven unidentified polar lipids. Ubiquinone Q-8 was detected as the predominant quinone. The genomic DNA G + C content of strain TP187T was determined to be 43.7 mol%. In addition, the maximum values of in silico DNA–DNA hybridization (isDDH) and average nucleotide identity (ANI) between strain TP187T with V. chagasii LMG 21353T were 22.40 and 77.50% respectively. Both values are below the proposed cutoff levels for species delineation, i.e. 70 and 95%, respectively. Combined data from phenotypic, phylogenetic, isDDH and ANI data demonstrated that the strain TP187T is representative of a novel species of the genus Vibrio, for which we propose the name Vibrio profundi sp. nov. (type strain TP187T = KACC 18555T = CGMCC 1.15395T).

Streptococcus castoreus , an uncommon group A Streptococcus in beavers Abstract Streptococcus castoreus is a rarely encountered beta-haemolytic group A Streptococcus with high tropism for the beaver as host. Based on 27 field isolates under study, evidence strongly suggests that S. castoreus behaves as an opportunistic pathogen in beavers. Although it belongs to the resident mucosal microbiota, this Streptococcus species is associated with purulent lesions in diseased animals. With few exceptions, isolates proved to be highly similar in a panel of phenotypic (including biochemistry, resistance pattern, MALDI-TOF mass spectrometry and Fourier transform-infrared spectroscopy) and classic molecular (16S rRNA and sodA gene) analyses, and thus did not show any specific pattern according to host species or spatio-temporal origin. Conversely, S. castoreus isolates were differentiated into a multitude of pulsed-field gel electrophoresis ‘pulsotypes’ that did not seem to reflect true epidemiologic lineages. In contrast, single reactions of genomic fingerprinting using BOX-, (GTG)5- and RAPD-PCRs revealed at least subclusters with respect to host species, geographic origin or year, and confirmed the co-colonization of individuals with more than one isolate. In addition to isolates from free-ranging Eurasian beavers (Castor fiber), this study includes S. castoreus from captive North American beavers (Castor canadensis) for the first time.