Epibiotic Vibrio luminous bacteria isolated from some hydrozoa and bryozoa species

A survey of epibiont hydrozoans on Sargassum

The brown alga Sargassum provides a natural substrate occupied by hydrozoans in shallow marine waters. A global count in 2007 listed 39 epibiotic species of Hydrozoa growing on Sargassum, but more studies have been published since, therefore, an update is timely, particularly due to the increased abundance of Sargassum in the Caribbean. This review, based on a recent literature survey and new records from Mexico, includes 133 publications of epibiotic hydrozoans on Sargassum spanning 220 years, from 1802 to 2022. A total of 131 hydrozoan species were recorded on 26 species of Sargassum, most belonging to the subclass Hydroidolina (130), with only one record of a trachyline medusa (Gonionemus vertens, subclass Trachylinae). Most publications centered on the Tropical Atlantic, where the greatest number of hydrozoan species (67 species) were recorded. All hydrozoan species possess a hydrorhiza, except one hydromedusae species that attach to Sargassum via adhesive tentacles. Most of the hydrozoan species associated with Sargassum exhibited a benthic life cycle (93 species) and are comprised of erect, branched colonies (67 species) and large hydrothecae (69 species). Although the number of studies of epibiotic hydrozoans on Sargassum has increased since the mid-20th century, nevertheless hydrozoan richness has not reached an asymptote. Therefore, more sampling of Sargassum species would likely identify more hydrozoan species associated with Sargassum, especially among benthic Sargassum, and might help reveal potential biogeographical and ecological patterns between Sargassum and hydrozoan epibionts.

An Integrated Monitoring Approach to the Evaluation of the Environmental Impact of an Inshore Mariculture Plant (Mar Grande of Taranto, Ionian Sea)

The results of an ex-ante survey aiming to assess the impact of a fish farm in the Mar Grande of Taranto (southern Italy, Mediterranean Sea) on the surrounding environment are reported. There, the implementation of an innovative IMTA plant was planned, with the goals of environment bioremediation and commercially exploitable biomass production. Analyses were conducted in February and July 2018. Both seawater and sediments were sampled at the four corners of the fish farm to detect the existing biological and physico-chemical features. The investigation was performed to identify the best area of the farming plant for positioning the bioremediating system, but also to obtain a data baseline, to compare to the environmental status after the bioremediating action. Data were also analyzed by canonical analysis of principal coordinates (CAP). All the measurements, in particular, microbiology and macrobenthic community characterization using AZTI's Marine Biotic Index (AMBI) and the Multivariate-AMBI (M-AMBI) indices, suggest that the effect of fish farm waste was concentrated and limited to a small portion of the investigated area in relation to the direction of the main current. A site named A3, which was found to be the most impacted by the aquaculture activities, especially during the summer season, was chosen to place the bioremediation system.

An Integrative, Multiparametric Approach for the Comprehensive Assessment of Microbial Quality and Pollution in Aquaculture Systems

As the aquaculture sector significantly expanded worldwide in the past decades, the concept of sustainable aquaculture has developed with the challenge of not only maximizing benefits but also minimizing the negative impacts on the environment assuring, at the same time, food security. In this framework, monitoring and improving the microbiological water quality and animal health are a central topic. In the present study, we evaluated the seawater microbiological quality in a mariculture system located in a Mediterranean coastal area (Northern Ionian Sea, Italy). We furnished, for the first time, a microbial inventory based on conventional culture-based methods, integrated with the 16S rRNA gene metabarcoding approach for vibrios identification and diversity analyses, and further implemented with microbial metabolic profiling data obtained from the Biolog EcoPlate system. Microbiological pollution indicators, vibrios diversity, and microbial metabolism were determined in two different times of the year (July and December). All microbial parameters measured in July were markedly increased compared to those measured in December. The presence of potentially pathogenic vibrios is discussed concerning the risk of fish disease and human infections. Thus, the microbial inventory here proposed might represent a new multiparametric approach for the suitable surveillance of the microbial quality in a mariculture system. Consequently, it could be useful for ensuring the safety of both the reared species and the consumers in the light of sustainable, eco-friendly aquaculture management.

Ramlibacter pinisoli sp. nov., a novel bacterial species isolated from pine garden soil

A Gram-stain-negative, aerobic, non-motile and rod- or coccoid-shaped novel bacterial strain, designated MAH-25^T, was isolated from soil sampled in a pine garden. The colonies were observed to be light pink-coloured, smooth, spherical and 1-2 mm in diameter when grown on nutrient agar for 2 days. Strain MAH-25^T was found to be able to grow at 15-35 °C, at pH 5.0-8.0 and at 0-2.0 % NaCl. Cell growth occurred on Reasoner's 2A agar and nutrient agar. The strain was found to be positive in both oxidase and catalase tests. According to 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Ramlibacter and closely related to Ramlibacter solisilvae 5-10^T (98.0 % similarity), Ramlibacter henchirensis TMB834^T (97.7 %), Ramlibacter tataouinensis TTB310^T (97.6 %) and Ramlibacter rhizophilus YS3.2.7^T (97.3 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain MAH-25^T and the four closely related type strains were in the range of 78.8-81.3 % and 22.3-24.1 %, respectively. The novel strain MAH-25^T has a draft genome size of 5 505 957 bp (11 contigs), annotated with 5210 protein-coding genes, 46 tRNA and three rRNA genes. The genomic DNA G+C content was determined to be 70.3 mol%. The predominant isoprenoid quinone was ubiquinone 8 (Q-8). The major fatty acids were identified as C_16 : 0, summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c). The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of DNA-DNA hybridization, genotypic analysis, chemotaxonomic and physiological data, strain MAH-25^T represents a novel species within the genus Ramlibacter, for which the name Ramlibacter pinisoli sp. nov. is proposed, with MAH-25^T (=KACC 19839^T=CGMCC1.13660^T) as the type strain.

Sphingomonas horti sp. nov., a novel bacterial species isolated from soil of a tomato garden

A novel bacterial strain, designated MAH-20^T, was isolated from a soil sample of a tomato garden. Cells of strain MAH-20^T were Gram-stain negative, aerobic, motile, and rod-shaped. The colonies were light brown colored, smooth, spherical, and 0.2-0.7 mm in diameter when grown on Luria-Bertani agar for 2 days. Strain MAH-20^T grows at 15-40 °C (optimum growth temperature 30-32 °C), at pH 5.0-10.0 (optimum growth pH 7.0) and at 0-2.0% NaCl. The strain showed positive activity for both oxidase and catalase tests. Cells were able to hydrolyze starch, DNA, urea, gelatin, L-arginine, and Tween 20. According to the 16S rRNA gene sequence similarity, the strain MAH-20^T was identified as a new member of the genus Sphingomonas and had the close sequence similarity with Sphingomonas changbaiensis V2M44^T (98.9%) and Sphingomonas tabacisoli X1-8^T (98.1%). The genomic ANI value between strain MAH-20^T and S. changbaiensis NBRC 104936^T was 84.4%. The novel strain MAH-20^T has a draft genome size of 3,350,026 bp (25 contigs), annotated with 3210 protein-coding genes, 46 tRNA, and 3 rRNA genes. The genomic DNA G + C content of isolate was 67.3 mol%, the predominant quinone was ubiquinone 10 and the major fatty acids were C_16:0, C_17:1 ω6c and summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c). On the basis of DNA-DNA hybridization results, phenotypic, genotypic, and chemotaxonomic data, the isolated strain MAH-20^T represents a novel species, for which the name Sphingomonas horti sp. nov. is proposed, with MAH-20^T as the type strain (= KACC 19746^T = CGMCC1.13658^T).

Sphingomonas chungangi sp. nov., a bacterium isolated from garden soil sample

A novel bacterial strain, designated MAH-6^T, was isolated from a garden soil sample. Cells were Gram-stain-negative, aerobic, non-motile and rod-shaped. The colonies were light yellow, smooth, circular and 0.6-1.2 mm in diameter when grown on nutrient agar for 3 days. Strain MAH-6^T grew at 15-35 °C, at pH 5.0-7.0 and with 0-0.5 % NaCl. Cell growth occurred on nutrient agar and Reasoner's 2A (R2A) agar. The strain was positive for both catalase and oxidase tests. Cells were able to hydrolyse starch, aesculin, Tween 20 and Tween 80. According to 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Sphingomonas and was most closely related to Sphingomonas polyaromaticivorans B2-7^T (98.2 % sequence similarity), Sphingomonas oligoaromativorans SY-6^T (96.9 %) and Sphingomonas morindae NBD5^T (96.6 %). The novel strain MAH-6^T has a draft genome size of 4 370 740 bp (28 contigs), annotated with 4199 protein-coding genes, 46 tRNA and three rRNA genes. The genomic DNA G+C content of the strain was determined to be 66.2 mol% and the predominant isoprenoid quinone is Q-10. The major fatty acids were identified as summed feature 8 (comprising C_18 : 1  ω7c and/or C_18 : 1  ω6c), C_14 : 0 2OH and C_16 : 0. The main polar lipids were phosphatidylcholine, sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Based on the results of phenotypic, genotypic, chemotaxonomic and DNA-DNA hybridization studies, strain MAH-6^T represents a novel species, for which the name Sphingomonas chungangi sp. nov. is proposed, with MAH-6^T as the type strain (=KACC 19292^T=CGMCC1.13654^T).

Aquitalea aquatilis sp. nov., isolated from Jungwon waterfall

A Gram-stain-negative, facultative anaerobic, motile, short rods and yellow-pigmented bacterium, designated strain THG-DN7.12^T, was isolated from water collected at Jungwon waterfall on Yongmun mountain, Republic of Korea. According to 16S rRNA gene sequence comparisons, strain THG-DN7.12^T was found to be most closely related to Aquitalea denitrificans 5YN1-3^T (98.9 % sequence similarity), Aquitalea magnusonii TRO-001DR8^T (98.7 %) and Aquitalea pelogenes P1297^T (98.0 %). The DNA-DNA relatedness between strain THG-DN7.12^T and its phylogenetically closest neighbours was below 70.0 %. The strain's DNA G+C content was 59.7 mol%. The major polar lipid was found to be phosphatidylethanolamine. Summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and C_16 : 0 were identified as the major fatty acids. Ubiquinone Q-8 was detected as the only respiratory quinone. These data supported the affiliation of strain THG-DN7.12^T to the genus Aquitalea. Strain THG-DN7.12^T was distinguished from related Aquitalea species by physiological and biochemical tests. Therefore, the novel isolate represents a novel species, for which the name Aquitalea aquatilis sp. nov. is proposed, with THG-DN7.12^T as the type strain (=KACC 18847^T=CCTCC AB 2016185^T).

The Microbial Community Associated with Rhizostoma pulmo: Ecological Significance and Potential Consequences for Marine Organisms and Human Health

Jellyfish blooms are frequent and widespread in coastal areas worldwide, often associated with significant ecological and socio-economic consequences. Recent studies have also suggested cnidarian jellyfish may act as vectors of bacterial pathogens. The scyphomedusa Rhizostoma pulmo is an outbreak-forming jellyfish widely occurring across the Mediterranean basin. Using combination of culture-based approaches and a high-throughput amplicon sequencing (HTS), and based on available knowledge on a warm-affinity jellyfish-associated microbiome, we compared the microbial community associated with R. pulmo adult jellyfish in the Gulf of Taranto (Ionian Sea) between summer (July 2016) and winter (February 2017) sampling periods. The jellyfish-associated microbiota was investigated in three distinct compartments, namely umbrella, oral arms, and the mucus secretion. Actinobacteria, Bacteroidetes, Chlamydiae, Cyanobacteria, Deinococcus-Thermus, Firmicutes, Fusobacteria, Planctomycetes, Proteobacteria, Rhodothermaeota, Spirochaetes, Tenericutes, and Thaumarchaeota were the phyla isolated from all the three R. pulmo compartments in the sampling times. In particular, the main genera Mycoplasma and Spiroplasma, belonging to the class Mollicutes (phylum Tenericutes), have been identified in all the three jellyfish compartments. The taxonomic microbial data were coupled with metabolic profiles resulting from the utilization of 31 different carbon sources by the BIOLOG Eco-Plate system. Microorganisms associated with mucus are characterized by great diversity. The counts of culturable heterotrophic bacteria and potential metabolic activities are also remarkable. Results are discussed in terms of R. pulmo ecology, the potential health hazard for marine and human life as well as the potential biotechnological applications related to the associated microbiome.

Arthrobacter sedimenti sp. nov., isolated from river sediment in Yuantouzhu park, China

A Gram-stain positive, motile, aerobic and rod-shaped strain (MIC A30^T) was isolated from river sediment in Yuantouzhu park, Wuxi City, China. Growth occurred at 20-40 °C, at pH 6.0-9.0 and at 0-5.0% NaCl. Strain MIC A30^T was moderately related to Arthrobacter liuii CGMCC 1.12778^T (97.9%), Arthrobacter pokkalii^T (97.9%) and Arthrobacter globiformis NBRC 12137^T (96.7%) by 16S rRNA analysis. The DNA-DNA relatedness values between strain MIC A30^T and these reference strains were below 30%. The DNA G+C content was 63.1 mol%. Average nucleotide identity (ANI) and genome-to-genome distance (GGD) values between strain MIC A30^T and A. liuii CGMCC 1.12778^T were 60.34% and 29.39%, respectively. Quinone was identified as MK-9(H2). Major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. Major fatty acids were iso-C_15:0, anteiso-C_15:0 and anteiso-C_17:0. Whole-cell sugars were galactose, mannose and rhamnose. The cell wall peptidoglycan contained A4α peptidoglycan type with lysine as the diagnostic diamino acid. Based on several taxonomic results, strain MIC A30^T is identified as a novel species in genus Arthrobacter, whose name is proposed as Arthrobacter sedimenti sp. nov. The type strain is MIC A30^T (= KACC 19599^T = CGMCC 1.13474^T).

Paenibacillus anseongense sp. nov. a Silver Nanoparticle Producing Bacterium Isolated from Rhizospheric Soil

A silver nanoparticle (AgNP) producing, Gram stain-positive, aerobic, motile, and rod-shaped novel bacterial strain, designated as MAH-34 ^T was isolated from rhizospheric soil of magnolia tree. The colonies were creamy white, smooth, circular, and 0.9-2.0 mm in diameter when grown on R2A agar. Strain MAH-34 ^T was found to be able to grow at 10-37 °C, at pH 6.0-9.5, and at 0-1% NaCl. The strain showed activity for both catalase, and oxidase tests, and was able to rapid synthesis of AgNPs. The TEM image revealed the spherical shape of biosynthesized AgNPs, and the size was 5 to 15 nm. Based on 16S rRNA gene sequence comparisons, the isolate was shown to be a member of genus Paenibacillus, and the close type strains were Paenibacillus chondroitinus DSM 5051 ^T (98.3%), Paenibacillus aceris KUDC4121^T (98.2%), Paenibacillus nebraskensis JJ-59 ^T (97.8%), Paenibacillus alginolyticus DSM 5050 ^T (97.6%), Paenibacillus ferrarius CY1^T (97.4%), Paenibacillus frigoriresistens YIM 016 ^T (97.3%), and Paenibacillus pocheonensis Gsoil 1138 ^T (97.3%). Strain MAH-34 ^T had a genome size of 8,647,010 bp. The genomic G + C content was 46.0 mol %. The major isoprenoid quinone was determined as menaquinone-7 (MK-7). The major cellular fatty acids were determined as C_{15:0 anteiso}, and C_{16:0 iso}. Based on the DNA-DNA hybridization results, genotypic analysis, chemotaxonomic, and physiological data, strain MAH-34 ^T represents a novel species, for which the name Paenibacillus anseongense sp. nov. is proposed, with MAH-34 ^T as the type strain (= KACC 19974 ^T = CGMCC1.16610 ^T).

Luteimonas cellulosilyticus sp. nov., Cellulose-Degrading Bacterium Isolated from Soil in Changguangxi National Wetland Park, China

A Gram-negative, motile, aerobic, and rod-shaped strain (MIC 1.5^T) was isolated from soil in Changguangxi national wetland park. Growth occurred at 20-45 °C, at pH 6.0-8.0, and at 0-4.0% NaCl. Based on 16S rRNA gene sequence analysis, strain MIC 1.5^T was related to were identified as Luteimonas dalianensis CGMCC 1.12191^T (95.3%), Luteimonas padinae DSM 101536^T (94.5%), Luteimonas huabeiensis DSM 26429^T (94.1%), and Luteimonas mephitis DSM 12574^T (92.5%). The DNA-DNA relatedness values between strain MIC 1.5^T , and these strains were well below 31%. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The DNA G+C content of strain MIC 1.5^T was 66.3 mol%. Average nucleotide identity (ANI) and genome-to-genome distance (GGD) values between strain MIC 1.5^T and L. dalianensis CGMCC 1.12191^T were 65.39% and 29.52%, respectively. The quinone was identified as Q-8. The major fatty acids were iso-C_15:0, iso-C_15:0 3OH, and iso-C_17:0 3OH and summed feature 3 (C_16:1ω7c and/or iso-C_15:0 2-OH). Based on the phylogenetic, physiological, and chemotaxonomic results, strain MIC 1.5^T represents a novel species of the genus Luteimonas, for which the name Luteimonas cellulosilyticus sp. nov. is proposed. The type strain is MIC 1.5^T (= KACC 19469^T = CCTCC AB 2017256^T).

Mucilaginibacter corticis sp. nov., isolated from bark of Pinus koraiensis

A gram-stain negative, aerobic, non-motile and rod-shaped novel bacterial strain, designated MAH-19^T, was isolated from bark of Pinus koraiensis. The colonies were observed to be light pink coloured, smooth, circular and 0.3-0.7 mm in diameter when grown on R2A agar for 2 days. Strain MAH-19^T was found to be able to grow at 10-35 °C (optimum 28-30 °C), at pH 6.0-8.0 (optimum 7.0) and at 0-0.5% NaCl (optimum 0%). Cell growth occurs on nutrient agar and R2A agar. The strain was found to be positive for both catalase and oxidase tests. Cells are able to hydrolyse aesculin and Tween 20, but not casein, gelatin, starch, L-tyrosine, DNA, L-arginine, urea or Tween 80. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Mucilaginibacter and to be closely related to Mucilaginibacter panaciglaebae BXN5-31^T (97.4% similarity), Mucilaginibacter antarcticus S14-88^T (97.2%) and Mucilaginibacter ximonensis XM-003^T (97.1%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-19^T and its close phylogenetic neighbours was below 45.0%. The novel strain MAH-19^T has a draft genome size of 5,335,442 bp (14 contigs), annotated with 4963 protein-coding genes, 44 tRNA and 6 rRNA genes. The genomic DNA G+C content was determined to be 42.7 mol%. The predominant isoprenoid quinone of strain MAH-19^T was identified as MK-7. The major fatty acids were identified as C_{15:0 iso} and summed feature 3 (comprising C_16:1ω7c and/or C_16:1ω6c). The DNA-DNA hybridization results and results of the genotypic analysis, in combination with chemotaxonomic and physiological data, demonstrated that strain MAH-19^T represents a novel species within the genus Mucilaginibacter, for which the name Mucilaginibacter corticis sp. nov. is proposed, with MAH-19^T (= KACC 19745^T = CGMCC1.13657^T) as the type strain.

Jellyfish summer outbreaks as bacterial vectors and potential hazards for marine animals and humans health? The case of Rhizostoma pulmo (Scyphozoa, Cnidaria)

Jellyfish represent an important component of marine food webs characterized by large fluctuations of population density, with the ability to abruptly form outbreaks, followed by rarity periods. In spite of considerable efforts to investigate how jellyfish populations are responding globally to anthropogenic change, available evidence still remains unclear. In the last 50 years, jellyfish are seemingly on the rise in a number of coastal areas, including the Mediterranean Sea, where jellyfish blooms periodically become an issue to marine and maritime human activities. Their impacts on marine organism welfare have been poorly quantified. The jellyfish, Rhizostoma pulmo, is an outbreak-forming scyphomedusa whose large populations spread across the Mediterranean, with increasing periodicity and variable abundance. Studies on cnidarian jellyfish suggested being important vectors of bacterial pathogens. In the present study, by combination of conventional culture-based methods and a high-throughput amplicon sequencing (HTS) approach, we characterized the diversity of the bacterial community associated with this jellyfish during their summer outbreak. Three distinct jellyfish compartments, namely umbrella, oral arms, and the mucus secretion obtained from whole specimens were screened for specifically associated microbiota. A total of 17 phyla, 30 classes, 73 orders, 146 families and 329 genera of microbial organisms were represented in R. pulmo samples with three major clades (i.e. Spiroplasma, Mycoplasma and Wolinella) representing over 90% of the retrieved total sequences. The taxonomic microbial inventory was then combined with metabolic profiling data obtained from the Biolog Eco-Plate system. Significant differences among the jellyfish compartments were detected in terms of bacterial abundance, diversity and metabolic utilization of 31 different carbon sources with the highest value of abundance and metabolic potential in the mucus secretion compared to the umbrella and oral arms. Results are discussed in the framework of the species ecology as well as the potential health hazard for marine organisms and humans.

Fluviicola chungangensis sp. nov., a bacterium isolated from rice field

A Gram-stain negative, aerobic, motile and rod-shaped novel bacterial strain, designated MAH-3^T, was isolated from soil sample of a rice field. The colonies were orange pigmented, smooth, circular and 0.4-0.9 mm in diameter when grown on R2A agar for 3 days. Strain MAH-3^T was found to grow at 10-40 °C (optimum 30 °C), pH 6.0-8.0 (optimum 7.0) and in the presence of 0-1.0% NaCl (optimum 0%). Cell growth occurs on R2A agar and Luria-Bertani agar, but not on nutrient agar, tryptone soya agar and MacConkey agar. Cells were positive for catalase test but negative for oxidase test. Cells were able to hydrolyze casein, gelatin, DNA and Tween 80. 16S rRNA gene sequence analysis revealed that strain MAH-3^T was most closely related to the genus Fluviicola and exhibited the highest sequence similarity to Fluviicola hefeinensis MYL-8^T (97.4%), Fluviicola taffensis RW262^T (96.2%) and Fluviicola kyonggii CA-1^T (95.6%). Strain MAH-3^T had a genome size of 4,271,694 bp and the genomic DNA G + C content was determined to be 41.7 mol%. The genome contained 19 contigs encoded by 3,664 protein-coding genes with 34 tRNA and 4 rRNA genes. The genomic ANI value between strain MAH-3^T and one of the closely related type strains, F. taffensis DSM 16823^T was 76.2%. The predominant isoprenoid quinone of isolated strain MAH-3^T was menaquinone-6 (MK-6). The major fatty acids were identified as C_{15:0 iso}, C_15:0 2OH and C_{17:0 iso} 3OH. On the basis of these phenotypic, genotypic and chemotaxonomic studies and DNA-DNA hybridization results, the isolated strain MAH-3^T represents a novel species, for which the name Fluviicola chungangensis sp. nov. is proposed, with MAH-3^T as the type strain (= KACC 19742^T = CGMCC 1.13750^T).

Sphingobium chungangianum sp. nov., isolated from rhizosphere of Pinus koraiensis

A novel Gram-staining negative, yellow-pigmented, non-motile, aerobic and rod-shaped bacterium, designated MAH-11^T, was isolated from rhizosphere of Pinus koraiensis and was characterised by using a polyphasic taxonomic approach. The colonies were smooth, circular and 0.3-1.0 mm in diameter when grown on R2A agar for 3 days. The strain was positive for both catalase and oxidase tests. Optimum growth temperature and pH were 28-30 °C and 7.0, respectively. Cell growth occurs on R2A agar, nutrient agar, Luria-Bertani agar and tryptone soya agar but not on MacConkey agar. The novel strain was found to be able to hydrolyse esculin but not casein, gelatin, starch, L-tyrosine, DNA, L-arginine, urea, Tween 20 and Tween 80. On the basis of 16S rRNA gene sequence analysis, strain MAH-11^T belongs to the genus Sphingobium and is closely related to Sphingobium quisquiliarum P25^T (98.1%), Sphingobium vermicomposti VC-230^T (97.8%), Sphingobium mellinum WI4^T (97.5%), Sphingobium barthaii KK22^T (97.2%) and Sphingobium fuliginis TKP^T (97.2%). In DNA-DNA hybridization tests, the DNA relatedness values between strain MAH-11^T and its close phylogenetic neighbors were below 45.0%. The DNA G+C content was 64.5 mol% and the predominant respiratory quinone was identified as ubiquinone-10. The major cellular fatty acids were summed feature 8 (C_18:1ω7c and/or C_18:1ω6c), summed feature 3 (C_16:1ω7c and/or C_16:1ω6c) and C_16:0. The DNA-DNA hybridization results in combination with chemotaxonomic and physiological data demonstrated that strain MAH-11^T represents a novel species within the genus Sphingobium, for which the name Sphingobium chungangianum is proposed. The type strain is MAH-11^T (= KACC 19836^T = CGMCC 1.13749^T).

Chitinophaga aurantiaca sp. nov., isolated from a soil sample from a tangerine field

A Gram-stain-negative, facultatively anaerobic, non-motile and rod-shaped bacterial strain, designated THG-SD5.5^T, 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 Chitinophaga and to be closely related to Chitinophaga ginsengihumi KACC 17604^T (97.9%) and Chitinophaga rupis KACC 14521^T (97.5%). The 16S rRNA gene sequence similarities with other species of the genus Chitinophaga were in the range 92.8-95.5%. Catalase test was positive. Oxidase test was negative. The DNA G + C content was determined to be 46.1 mol%. DNA-DNA hybridization values between strain THG-SD5.5^T and C. ginsengihumi KACC 17604^T and C. rupis KACC 14521^T were 45.1% and 15.6%, respectively. Strain THG-SD5.5^T was also found to be able to grow at 24-33 °C, at 0-5% NaCl and at pH 5.5-9.0. The major fatty acids were identified as anteiso-C_15:0, C_16:0, anteiso-C_17:0 and C_18:0. The dominant respiratory quinone was identified as menaquinone-7 (MK-7). The polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminolipid, two unidentified phospholipids and three unidentified lipids. Based on these phenotypic, genotypic and phylogenetic characterisations, strain THG-SD5.5^T (= KACC 19338^T = CGMCC 1.16304^T) is concluded to represent a novel species of the genus Chitinophaga, for which the name Chitinophaga aurantiaca sp. nov. is proposed.

Glaciecola amylolytica sp. nov., an amylase-producing bacterium isolated from seawater

A Gram-stain-negative, aerobic, non-motile and coccus-shaped bacterium (THG-3.7^T) was isolated from seawater. Growth occurred at 10-30 °C (optimum 25 °C), at pH 6-8 (optimum 7) and in the presence of 1-8 % (w/v) NaCl (optimum 4 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-3.7^T were identified as Paraglaciecola mesophila DSM 15026^T (95.3 % similarity), Glaciecola pallidula DSM 14239^T (95.2 %), Paraglaciecola aquimarina KCTC 32108^T (95.1 %), Paraglaciecola arctica KACC 14537^T (94.9 %), Glaciecola nitratireducens KCTC 12276^T (94.7 %) and Paraglaciecola psychrophila CGMCC 1.6130^T (94.7 %). 16S rRNA gene sequence similarities among strain THG-3.7^T and other species were lower than 94.7 %. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The quinone system was composed of Q-8. The major fatty acids were C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain THG-3.7^T was 47.9 mol%. On the basis of the data presented, strain THG-3.7^T represents a novel species of the genus Glaciecola, for which the name Glaciecola amylolytica sp. nov. is proposed. The type strain is THG-3.7^T (=KACC 19478^T=CCTCC AB 2017258^T).

Mucilaginibacter formosus sp. nov., a bacterium isolated from road-side soil

A Gram-stain negative, aerobic, non-motile and rod-shaped novel bacterial strain, designated as MAH-5^T, was isolated from a road-side soil sample and was characterised by using a polyphasic taxonomic approach. The colonies were observed to be yellowish orange in colour, smooth, circular and 0.3-0.7 mm in diameter when grown on nutrient agar for 2 days. Strain MAH-5^T was found to be able to grow at 15-35 °C and at pH 4.0-8.0. The strain was observed to be positive for both the catalase and oxidase tests. Cells were found to be able to hydrolyse aesculin, gelatin and starch. By 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Mucilaginibacter and to be closely related to Mucilaginibacter panaciglaebae BXN5-31^T (98.35%), Mucilaginibacter soyangensis HME6664^T (97.82%), Mucilaginibacter antarcticus S14-88^T (97.49%) and Mucilaginibacter ximonensis XM-003^T (97.06%). In DNA-DNA hybridization tests, the DNA relatedness values between strain MAH-5^T and its close phylogenetic neighbors were below 45.0%. The genomic DNA G + C content of strain MAH-5^T was determined to be 41.5 mol% and the predominant isoprenoid quinine was identified as MK-7. The major fatty acids were identified as C_{15:0 iso} and summed feature 3 (comprising C_16:1ω7c and/or C_16:1ω6c). The genetic characteristics, in combination with chemotaxonomic and physiological data, demonstrated that the isolated strain MAH-5^T represents a novel species within the genus Mucilaginibacter, for which the name Mucilaginibacter formosus sp. nov. is proposed, with MAH-5^T as the type strain (= KACC 19291^T = CGMCC1.16489^T).

Bhargavaea changchunensis sp. nov. isolated from soil in China

A Gram-staining-positive, aerobic, rod-shaped (201802YP6^T) bacteria was isolated from soil, Northeast of China. Growth occurred at 10-40 °C (optimum 25-30 °C), at pH 6.0-8.0 (optimum 7.0) and at 0-2% NaCl. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbors of strain 201802YP6^T were identified as Bhargavaea cecembensis DSE10^T (99.52%), Bhargavaea beijingensis ge10^T (99.45%), Bhargavaea indica KJW98^T (99.45%), Bhargavaea ullalensis ZMA19^T (98.81%), and Bhargavaea ginsengi ge14^T (98.76%). Levels of similarity among strain 201802YP6^T and other Bhargavaea species were lower than 98.76%. GyrB amino acid sequence-based analysis supported the phylogenetic position and also distinguished strain 201802YP6^T from the other species of the genus Bhargavaea. DNA-DNA hybridization values between strain 201802YP6^T and B. cecembensis, B. beijingensis, B. indica, B. ullalensis, B. ginsengi were 43.5%, 43%, 32.5%, 30.5% and 20.4%, respectively. The DNA G + C content of strain 201802YP6^T was 51.23 mol%. The average nucleotide identity (ANI) of the draft genome was 87.04% to B. cecembensis DSE10^T. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipids, phosphatidylethanolamine, and phosphatidyllipid. The predominant menaquinone was MK-8. The major fatty acids were iso-C_15:0 (39.91%), anteiso-C_15:0 (28.86%), anteiso-C_17:0 (6.30%) and C_16:0 (6.13%). On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain 201802YP6^T represents a novel species of the genus Bhargavaea, for which the name Bhargavaea changchunensis sp. nov. is proposed. The type strain is 201802YP6^T (= CGMCC 1.13508^T = KCTC 33975^T).

Microvirga rosea sp. nov.: a nanoparticle producing bacterium isolated from soil of rose garden

A Gram-stain negative, aerobic, non-motile, and rod-shaped novel bacterial strain, designated MAH-2^T, was isolated from a soil sample of rose garden and was characterized using a polyphasic approach. The colonies were light pink color, smooth, circular and 0.2-0.6 mm in diameter when grown on nutrient agar for 3 days. Strain MAH-2^T grows at 15-40 °C (optimum growth temperature 30 °C), at pH 5.0-7.0 (optimum growth pH 6.5) and at 0-2% NaCl (optimum 0-0.5%). Cell growth occurs on nutrient agar and R2A agar but not on tryptone soya agar, luria-bertani agar and MacConkey agar. The strain was positive for both catalase and oxidase tests. The strain was able to synthesis of silver nanoparticles. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Microvirga and was most closely related to Microvirga soli R491^T (96.7% sequence similarity), Microvirga subterranea Fail4^T (96.4%), Microvirga guangxiensis 25B^T (96.0%) and Microvirga aerophila 5420S-12^T (95.9%). The genomic DNA G + C content of isolated strain was determined to be 62.5 mol% and the predominant isoprenoid quinone was Q-10. The major fatty acids were identified as summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c) and C_19:0 cyclo ω8c. On the basis of these phenotypic, genotypic, and chemotaxonomic studies and DNA-DNA hybridization results, the isolated strain MAH-2^T represents a novel species, for which the name Microvirga rosea sp. nov. is proposed, with MAH-2^T as the type strain (= KACC 19290^T = CGMCC1.16488^T).

Aglaophenia octodonta (Cnidaria, Hydrozoa) and the Associated Microbial Community: a Cooperative Alliance?

Recently, genetic approaches have revealed a surprising bacterial world as well as a growing knowledge of the enormous distribution of animal-bacterial interactions. In the present study, the diversity of the microorganisms associated to the hydroid Aglaophenia octodonta was studied with epifluorescence, optical, and scanning electron microscopy. Small subunit ribosomal RNA gene sequencing with "universal" and taxon-specific primers allowed the assignment of the microalgae to Symbiodinium and the peritrich ciliates to Pseudovorticella, while the luminous vibrios were identified as Vibrio jasicida of the Harvey clade. To understand the possible relationships among Vibrio jasicida, Symbiodinium, A. octodonta, and Pseudovorticella, specific treatments were conducted in microcosm experiments, with the antibiotic ampicillin and other substances that interfere with bacterial and hydroid metabolism. Treatment of A. octodonta with ampicillin resulted in a decrease of bacterial luminescence followed by Pseudovorticella detachment and Symbiodinium expulsion and suggesting that these microorganisms form a "consortium" with beneficial metabolic interdependence. This hypothesis was reinforced by the evidence that low concentrations of hydrogen peroxide, which stimulate the bacterial oxidative metabolism and luminescence by releasing oxygen, were able to counteract the detrimental effect of ampicillin on the stability of the studied A. octodonta association. A model is proposed in which microalgae that release oxygen during photosynthesis are useful to luminous bacteria for their metabolism and for establishing/maintaining symbiosis leading to a close alliance and mutual benefit of the system A. octodonta-Vibrio jasicida-Pseudovorticella sp.-Symbiodinium sp.

Sphingobium tyrosinilyticum sp. nov., a tyrosine hydrolyzing bacterium isolated from Korean radish garden

A yellow-pigmented novel bacterial strain, MAH-12^T, was isolated from a soil sample of Korean radish garden and was characterized using a polyphasic approach. Cells were Gram-staining negative, non-motile and rod-shaped. The strain was aerobic, catalase positive, optimum growth temperature and pH were 28-30 °C and 6.0, respectively. The novel strain is able to hydrolyze L-tyrosine, starch, esculin and 4-nitrophenyl-β-D-galactopyranoside. On the basis of 16S rRNA gene sequence analysis, strain MAH-12^T belongs to the genus Sphingobium and is most closely related to several Sphingobium type strains (97.2-97.8%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-12^T and its closest phylogenetic neighbors was below 45.0%. The DNA G + C content was 64.0 mol% and the predominant respiratory quinone was ubiquinone-10. The major cellular fatty acids were summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) and C_16:0. The DNA-DNA hybridization results and results of the genotypic analysis in combination with chemotaxonomic and physiological data demonstrated that strain MAH-12^T represented a novel species within the genus Sphingobium, for which the name Sphingobium tyrosinilyticum is proposed. The type strain is MAH-12^T (= KACC 19297^T = CGMCC 1.16225^T). The NCBI GenBank accession number for the 16S rRNA gene sequence of strain MAH-12^T is KY964278 and the digital protologue database taxon number of strain MAH-12^T is TA00463.

Scopulibacillus cellulosilyticus sp. nov., a cellulose-degrading bacterium isolated from tea

A Gram-stain positive, aerobic, non-motile, endospore-forming and rod-shaped strain (THG-NT9^T) was isolated from a green tea sample. Growth occurred at 20-45 °C (optimum 28-35 °C), at pH 6.0-8.0 (optimum 7.0) and at 0-2.0% NaCl (optimum 0%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-NT9^T were identified as Scopulibacillus daqui DSM 28236^T (98.6%), Scopulibacillus darangshiensis DSM 19377^T (97.4%), Pullulanibacillus pueri CGMCC 1.12777^T (96.7%) and Pullulanibacillus camelliae CGMCC 1.15371^T (96.3%). The DNA G + C content of strain THG-NT9^T was determined to be 47.5 mol %. DNA-DNA hybridization values between strain THG-NT9^T and S. daqui DSM 28236^T, S. darangshiensis DSM 19377^T, P. pueri CGMCC 1.12777^T, P. camelliae CGMCC 1.15371^T and Pullulanibacillus naganoensis DSM 10191^T were 41.3 ± 0.1 (39.4 ± 0.4% reciprocal analysis), 39.1 ± 0.1 (37.3 ± 0.1%), 21.4 ± 0.7 (20.1 ± 0.3%), 20.7 ± 0.1 (20.1 ± 0.4%) and 12.1 ± 0.2% (8.3 ± 0.2%). The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and three unidentified lipids. The quinone was identified as MK-7. The major fatty acids were C_18:3 ω7c, iso-C_15:0, iso-C_16:0, iso-C_17:0 and anteiso-C_17:0. The cell wall type was determined to be A1γ peptidoglycan with meso-diaminopimelic acid as the diagnostic diamino acid plus alanine and glutamic acid and glucose as the cell wall sugar. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics, and DNA-DNA hybridization data, strain THG-NT9^T represents a novel species of the genus Scopulibacillus, for which the name Scopulibacillus cellulosilyticus sp. nov. is proposed. The type strain is THG-NT9^T (= KCTC 33918^T = CGMCC 1.16305^T).

Luteibacter pinisoli sp. nov., a casein degrading bacterium isolated from rhizospheric soil of Pinus koraiensis

A yellow pigmented, Gram-staining negative, motile and rod-shaped novel bacterial strain, designated MAH-14^T was isolated from rhizospheric soil and was characterized using a polyphasic approach. The isolated strain was aerobic, oxidase and catalase were positive, optimum growth temperature and pH were 28-30 °C and 6.5, respectively. The novel strain is able to hydrolyze casein, starch, esculin, gelatin, L-tyrosine, DNA, tween 80, tween 20, L-arginine and 4-nitrophenyl-BD-galactopyranoside. On the basis of 16S rRNA gene sequence analysis, strain MAH-14^T belongs to the genus Luteibacter and is most closely related to Luteibacter yeojuensis R2A16-10^T (98.5%), Luteibacter anthropi CCUG 25036^T (98.4%) and Luteibacter rhizovicinus LJ96^T (98.3%). In DNA-DNA hybridization experiments, the DNA relatedness between strain MAH-14^T and its closest phylogenetic neighbor was below 45.0%. The predominant respiratory quinone and the DNA G + C content of the novel strain were ubiquinone-8 and 63.5 mol%, respectively. The novel strain MAH-14^T is able to produce flexirubin-type pigments. The major cellular fatty acids were C_{15:0 iso}, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and summed feature 9 (C_{17:1 iso} ω9c and/or C_16:0 10-methyl). The DNA-DNA hybridization results and results of the genotypic analysis in combination with chemotaxonomic and physiological data revealed that strain MAH-14^T represented a novel species within the genus Luteibacter, for which the name Luteibacter pinisoli, is proposed. The type strain is MAH-14^T (= KACC 19298^T = CGMCC 1.16227^T).

Paracoccus pueri sp. nov., isolated from Pu'er tea

A Gram-stain negative, aerobic, short rod-shaped, motile by flagella bacterial strain (THG-N2.35^T), was isolated from Pu'er tea. Growth occurred at 10-40 °C (optimum 28 °C), at pH 4-7 (optimum 7) and at 0-5% NaCl (optimum 1%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-N2.35^T were identified as Paracoccus hibisci KACC 18632^T (99.0%), Paracoccus tibetensis CGMCC 1.8925^T (98.7%), Paracoccus beibuensis CGMCC 1.7295^T (98.2%), Paracoccus aestuarii KCTC 22049^T (98.2%), Paracoccus rhizosphaerae LMG 26205^T (98.1%), Paracoccus zeaxanthinifaciens ATCC 21588^T (97.1%), Paracoccus marcusii DSM 11574^T (97.0%). Levels of similarity between strain THG-N2.35^T and other Paracoccus species were lower than 97.0%. DNA-DNA hybridization values between strain THG-N2.35^T and P. hibisci KACC 18632^T, P. tibetensis CGMCC 1.8925^T, P. beibuensis CGMCC 1.7295^T, P. aestuarii KCTC 22049^T, P. rhizosphaerae LMG 26205^T, P. zeaxanthinifaciens ATCC 21588^T, P.marcusii DSM 11574^T were 47.5% (42.3%, reciprocal analysis), 36.1% (32.3%), 24.7% (22.1%), 19.2% (16.3%), 11.3% (8.8%), 11.1% (10.8%), 6.1% (5.8%), respectively. The DNA G+C content of strain THG-N2.35^T was 62.3 mol%. The polar lipids were diphosphatidylglycerol, phosphatidyl-N-methylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. The quinone was ubiquinone-10 (Q-10). The major fatty acids were C_10:0 3OH, C_16:0, C_18:0 and C_18:1 ω7ϲ. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-N2.35^T represent a novel species of the genus Paracoccus, for which the name Paracoccus pueri sp. nov. is proposed. The type strain is THG-N2.35^T (= KACC 18934^T = CCTCC AB 2016177^T).

Flavobacterium chungangensis sp. nov., a Bacterium Isolated from Soil of Chinese Cabbage Garden

A novel bacterial strain MAH-10^T was isolated from soil sample of a Chinese cabbage garden, Republic of Korea and was characterized using a polyphasic approach. Cells were Gram-staining negative, rod-shaped, yellowish orange colored, and motile. The strain was aerobic, catalase and oxidase are positive, and optimum growth temperature and pH were 28 °C and 6.5, respectively. Flexirubin-type pigments were found to be present. On the basis of 16S rRNA gene sequence analysis, strain MAH-10^T belongs to the genus Flavobacterium and is most closely related to Flavobacterium tyrosinilyticum KCTC 42726^T (98.7%). On the basis of phylogenetic tree, other closely related species are Flavobacterium banpakuense KACC 14225^T (98.3%) and Flavobacterium chungbukense KACC 15048^T (97.6%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-10^T and its closest phylogenetic neighbor was below 45.0%. The DNA G+C content was 37.2 mol% and the predominant respiratory quinone was menaquinone-6. The major cellular fatty acids were C_15:0 iso, C_16:0, and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c). On the basis of DNA-DNA hybridization results and genotypic, chemotaxonomic, and physiological data analysis, it is demonstrated that strain MAH-10^T represented a novel species within the genus Flavobacterium, for which the name Flavobacterium chungangensis is proposed. The type strain is MAH-10^T (=KACC 19296^T=CGMCC 1.16226^T). The NCBI GenBank accession number for the 16S rRNA gene sequence of strain MAH-10^T is KY964277 and the digital protologue database (DPD) Taxon Number of strain MAH-10^T is TA00296.

Actinotalea solisilvae sp. nov., isolated from forest soil and emended description of the genus Actinotalea

A Gram-stain-positive, aerobic, non-motile and short-rod-shaped actinobacterium, designated THG-T121^T, was isolated from forest soil. Growth occurred at 10-40 °C (optimum 28-30 °C), at pH 6-8 (optimum 7) and at 0-4 % NaCl (optimum 1 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T121^T were identified as Actinotalea ferrariae KCTC 29134^T (97.9 %), Actinotalea fermentans KCTC 3251^T (97.3 %), Cellulomonas carbonis KCTC 19824^T (97.2 %). 16S rRNA gene sequence similarities among strain THG-T121^T and other recognized species were lower than 97.0 %. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two phosphatidylinositol mannosides, one unidentified phospholipid, three unidentified glycolipids and one unidentified lipid. The isoprenoid quinone was menaquinone (MK-10(H4)). The major fatty acids were anteiso-C15 : 0, anteiso-C15 : 1 A, C16 : 0, iso-C16 : 0, anteiso-C17 : 0 and iso-C17 : 0. The whole-cell sugars of strain THG-T121^T were rhamnose, ribose, mannose and glucose. The peptidoglycan type of strain THG-T121^T is A4β, containing l-Orn-D-Ser-L-Asp. The DNA G+C content of strain THG-T121^T was 72.4 mol%. DNA-DNA hybridization values between strain THG-T121^T and A. ferrariae KCTC 29134^T, A. fermentans KCTC 3251^T and C. carbonis KCTC 19824^T were 30.2 % (27.3 %, reciprocal analysis), 28.4 %, (17.3 %) and 16.9 %, (9.3 %), respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T121^T represents a novel species of the genus Actinotalea, for which the name Actinotaleasolisilvae sp. nov. is proposed. The type strain is THG-T121^T (=KACC 19191^T=CGMCC 4.7389^T).

Bacterial bioluminescence onset and quenching: a dynamical model for a quorum sensing-mediated property

We present an effective dynamical model for the onset of bacterial bioluminescence, one of the most studied quorum sensing-mediated traits. Our model is built upon simple equations that describe the growth of the bacterial colony, the production and accumulation of autoinducer signal molecules, their sensing within bacterial cells, and the ensuing quorum activation mechanism that triggers bioluminescent emission. The model is directly tested to quantitatively reproduce the experimental distributions of photon emission times, previously measured for bacterial colonies of Vibrio jasicida, a luminescent bacterium belonging to the Harveyi clade, growing in a highly drying environment. A distinctive and novel feature of the proposed model is bioluminescence 'quenching' after a given time elapsed from activation. Using an advanced fitting procedure based on the simulated annealing algorithm, we are able to infer from the experimental observations the biochemical parameters used in the model. Such parameters are in good agreement with the literature data. As a further result, we find that, at least in our experimental conditions, light emission in bioluminescent bacteria appears to originate from a subtle balance between colony growth and quorum activation due to autoinducers diffusion, with the two phenomena occurring on the same time scale. This finding is consistent with a negative feedback mechanism previously reported for Vibrio harveyi.

Chryseomicrobium deserti sp. nov., isolated from desert soil in South Korea

A Gram-stain positive, aerobic, non-motile, rod-shaped bacterium (THG-T1.18^T) was isolated from desert soil. Growth occurred at 20-35 °C (optimum 28-30 °C), at pH 5-7 (optimum 7) and at 0-4 % NaCl (optimum 0-1 %). Based on 16S rRNA sequence analysis, the nearest phylogenetic neighbours of strain THG-T1.18^T were identified as Chryseomicrobium amylolyticum DSM 23442^T (96.6 %), Chryseomicrobium imtechense JCM 16573^T (96.3 %) and Chryseomicrobium aureum KACC 17219^T (96.1 %). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and one unidentified glycolipid. The quinone system was composed of MK-7, MK-8 and MK-6. The major fatty acids were iso C15 : 0 and anteiso C15 : 0. The type of peptidoglycan was A4β, containing of l-Orn-D-Glu. The DNA G+C content of strain THG-T1.18^T was 50.4 mol%. DNA-DNA hybridization values between strain THG-T1.18^T and C. amylolyticum DSM 23442^T, C. imtechense JCM 16573^T, C. aureum KACC 17219^T were 24.7 % (20.1 % reciprocal analysis), 19.5 % (16.1 %) and 10.4 % (6.7 %) respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T1.18^T represents a novel species of the genus Chryseomicrobium, for which the name Chryseomicrobium deserti sp. nov. is proposed. The type strain is THG-T1.18^T (=KACC 18929^T=CCTCC AB 2016179^T).

Ramlibacter rhizophilus sp. nov., isolated from rhizosphere soil of national flower Mugunghwa from South Korea

A Gram-negative, aerobic, non-motile, long rods or coccoid without flagellum strain, designated THG-YS3.2.7^T, was isolated from therhizosphere soil of a Mugunghwa flower collected from Kyung Hee University, Yongin, South Korea. Growth occurred at 10-40 °C (optimum 28-37 °C), at pH 6-8 (optimum 7) and at 0-5 % NaCl (optimum 1 %). The predominant ubiquinone was ubiquinone 8 (Q-8). The major cellular fatty acids were C10 : 0, C10 : 0 3OH, C16 : 0, C17 : 0, C17 : 0 cyclo, C18 : 0, C18 : 3ω6c (6,9,12), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1 ω7c and/or C18 : 1ω6c). The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylcholine (PC). The DNA G+C content of strain THG-YS3.2.7^T was 69.4 mol%. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-YS3.2.7^T were identified as Ramlibacter henchirensis DSM 14656^T (97.92 %), Ramlibacter tataouinensis DSM 14655^T (97.90 %), Ramlibacter solisilvae KACC 17567^T (97.04 %). DNA-DNA hybridization values between strain THG-YS3.2.7^T and R. henchirensis DSM 14656^T, R. tataouinensis DSM 14655^T, R. solisilvae KACC 17567^T were 32.5±1.5, 43.1±1.1, 42.8±1.1 %, respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-YS3.2.7^T represent a novel species of the genus Ramlibacter, for which the name Ramlibacter rhizophilus sp. nov. is proposed. The type strain is THG-YS3.2.7^T (=KCTC 52083^T=CCTCC AB 2015357^T).

Microbacterium hibisci sp. nov., isolated from rhizosphere of mugunghwa (Hibiscus syriacus L.)

A Gram-stain-positive, aerobic, non-motile, short-rod shaped actinobacterium, designated THG-T2.14T, was isolated from soil sampled from the rhizosphere of mugunghwa. Growth occurred at 10-40 °C (optimum 30 °C), at pH 5.0-10.0 (optimum 7.0) and at 0-7.0 % NaCl (optimum 3.0 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.14T were identified as Microbacterium yannicii DSM 23203T (98.8 %), Microbacterium trichothecenolyticum DSM 8608T (98.8 %), Microbacterium arthrosphaerae DSM 22421T (98.7 %) and Microbacterium jejuense KACC 17124T (98.4 %). The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified lipid, two unidentified phospholipids and two unidentified phosphoglycolipids. The menaquinones were MK-12, and MK-13. The major polyamine was spermidine. The peptidoglycan contained ornithine, alanine, glycine, homoserine and glutamic acid. The diagnostic diamino acid was ornithine. The acyl type of the muramic acid was glycolyl. The whole-cell sugars were rhamnose, ribose, galactose, arabinose, xylose and glucose. The DNA G+C content of strain THG-T2.14T was 71.2 mol%. The DNA-DNA relatedness between strain THG-T2.14T and its closest reference strains were significantly lower than the threshold value of 70 %. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.14T represents a novel species of the genus Microbacterium, for which the name Microbacterium hibisci sp. nov. is proposed. The type strain is THG-T2.14T (=KACC 18931T=CCTCC AB 2016180T).

Paracoccus hibisci sp. nov., isolated from the rhizosphere of Hibiscus syriacus L. (Mugunghwa flower)

A Gram-stain-negative, aerobic, short-rod-shaped bacterium, motile by means of one flagellum (THG-T2.8T), was isolated from the rhizosphere of Mugunghwa flower. Growth occurred at 10-37 °C (optimum 28 °C), at pH 6-8 (optimum 7) and with 0-5 % NaCl (optimum 1 %). The major quinone was ubiquinone-10 (Q-10). The major fatty acids were C10 : 0 3-OH, C16 : 0, C18 : 0 and C18 : 1ω7c. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid, two unknown phospholipids, one unknown glycolipid and one unidentified lipid. The DNA G+C content of strain THG-T2.8T was 65.5 mol%. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.8T were identified as Paracoccus tibetensis Tibet-S9a3T (98.6 %), Paracoccus aestuarii B7T (98.4 %), Paracoccus rhizosphaerae CC-CCM15-8T (98.3 %) and Paracoccus beibuensis JLT1284T (98.2 %). Levels of sequence similarity among strain THG-T2.8T and other species of the genus Paracoccus were lower than 98.0 %. DNA-DNA hybridization values between strain THG-T2.8T and P. tibetensis Tibet-S9A3TT, P. aestuarii B7T, P. rhizosphaerae CC-CCM15-8T and P. beibuensisJLT1284T were 36.5 % (38.8 %, reciprocal analysis), 32.8 % (34.8 %), 31.6 % (33.8 %) and 15.3 % (24.8 %), respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.8T represents a novel species of the genus Paracoccus, for which the name Paracoccus hibisci sp. nov. is proposed. The type strain is THG-T2.8T (=KACC 18932T=CCTCC AB 2016181T).

Spatial distribution of the culturable bacterial community associated with the invasive alga Caulerpa cylindracea in the Mediterranean Sea

Understanding the mechanisms underlying the complex seaweed-bacteria associations in nature may provide information on the fitness of an invasive host. This may require the use of different approaches. In this study, we employed, for the first time, the Biolog system-Ecoplates™ to analyze the functional diversity of the culturable fraction of the bacterial assemblages associated with the surface of Caulerpa cylindracea, the invasive seaweed of the Mediterranean Sea. Seaweed samples were collected at five sites across the basin. A high similarity in the bacterial activity, expressed as Average Well Color Development (AWCD), among the study sites was observed. Culturable heterotrophic bacteria at 22 °C showed mean values ranging from 1.4 × 10⁵ CFU g^-1 at Porto Cesareo (Ionian Sea, Italy) to 5.8 × 10⁶ CFU g^-1 at Othonoi, Diapontine Island (Ionian Sea, Greece). The analysis of the DNA sequences on isolated bacteria demonstrated that the genera Shewanella, Marinobacter, Vibrio, Granulosicoccus and the family Rhodobacteraceae are consistently present on C. cylindracea, irrespective of its geographical origin. The present study provided new insights into the complex association between bacteria and this algal species, suggesting a specific composition and function of the associated culturable bacteria across the basin.

Emticicia aquatilis sp. nov., isolated from a freshwater sample

A Gram-stain-negative, facultatively anaerobic, non-motile, rod-shaped and yellow-pigmented bacterium, designated strain THG-DN6.14T, was isolated from a freshwater sample near Donghaksa temple in Daejeon, South Korea. On the basis of the results of 16S rRNA gene sequence comparisons, THG-DN6.14T was found to be most closely related to Emticicia sediminis JBR12T (99.1 % sequence similarity), Emticicia oligotrophica DSM 17448T (97.6 %), Emticicia aquatica HMF2925T (96.5 %), and Emticicia ginsengisoliGsoil 085T (94.4 %). The DNA-DNA relatedness between THG-DN6.14T and its phylogenetically closest neighbours was below 65.0 %. The DNA G+C content was 43.3 mol%. The major polar lipids were found to be phosphatidylethanolamine, an unidentified glycolipid and an unidentified aminoglycolipid. The major fatty acids were identified as C16 : 0, iso-C15 : 0, iso-C17 : 0 3-OH, and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The respiratory quinone was menaquinone MK-7. These data supported the affiliation of THG-DN6.14T to the genus Emticicia. THG-DN6.14Tcould be distinguished from related species of the genus Emticicia by physiological and biochemical tests. Therefore, the novel isolate represents a novel species, for which the name Emticicia aquatilis sp. nov. is proposed, with THG-DN6.14T (=KACC 18540T=CGMCC 1.15958T) as the type strain.

Niabella hibiscisoli sp. nov., isolated from soil of a Rose of Sharon garden

A Gram-stain-negative, strictly aerobic, non-motile, rod-shaped and yellow-pigmented bacterium, designated strain THG-DN5.5T, was isolated from soil of a Rose of Sharon garden in Daejeon, South Korea. According to 16S rRNA gene sequence comparisons, strain THG-DN5.5T was found to be most closely related to Niabella yanshanensis CCBAU 05354T (97.7 % sequence similarity), Niabella ginsengisoli GR10-1T (97.0 %), 'Niabella terrae' ICM 1-15 (96.0 %), Niabella soli DSM 19437T (95.7 %) and Niabella aquatica RP-2T (95.6 %). The DNA-DNA relatedness between strain THG-DN5.5T and its phylogenetically closest neighbours was below 50.0 %. The DNA G+C content was 43.1 mol%. The major polar lipid of strain THG-DN5.5T was found to be phosphatidylethanolamine. The major fatty acids were identified as C16 : 0, iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. MK-7 was the only menaquinone present. These data supported the affiliation of strain THG-DN5.5T to the genus Niabella. Strain THG-DN5.5T was distinguished from related species of the genus Niabellaby physiological and biochemical tests. In conclusion, strain THG-DN5.5T represents a novel species of the genus Niabella, for which the name Niabella hibiscisolisp. nov. is proposed. The type strain is THG-DN5.5T (=KACC 18857T=CCTCC AB 2016086T).

Lysobacter humi sp. nov., a bacterium isolated from rice field

A novel bacterial strain THG-PC4^T was isolated from soil sample of rice field and was characterized by using a polyphasic approach. Cells were Gram-negative, bright yellow colored, nonmotile and rod shaped. The strain was aerobic and catalase positive, optimum growth temperature, and pH were 28 °C and 7, respectively. On the basis of 16S rRNA gene sequence analysis, strain THG-PC4^T belongs to the genus Lysobacter and is most closely related to Lysobacter fragariae KCTC 42236^T, followed by Lysobacter oryzae KCTC 22249^T, Lysobacter tyrosinelyticus KCTC 42235^T, Lysobacter terrae KACC 17646^T, Lysobacter yangpyeongensis KACC 11407^T, Lysobacter rhizosphaerae KCTC 42237^T and Lysobacter niabensis KACC 11587^T. In DNA-DNA hybridization tests, the DNA relatedness between strain THG-PC4^T and its closest phylogenetic neighbors was below 45 %. The DNA G + C content was 66.6 mol %, and the predominant respiratory quinone was ubiquinone-8. Flexirubin-type pigments were found to be present. The major cellular fatty acids were iso-C_16:0, iso-C_17:1 ω9c, iso-C_17:0 and iso-C_11:0 3OH. The predominant polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA-DNA hybridization, genotypic, chemotaxonomic and physiological data demonstrated that strain THG-PC4^T represented a novel species within the genus Lysobacter, for which the name Lysobcater humi is proposed. The type strain is THG-PC4^T (=KACC 18284^T = CCTCC AB 2015292^T).