Adhaeribacter aquaticus gen. nov., sp. nov., a Gram-negative isolate from a potable water biofilm

Sabulibacter ruber gen. nov., sp. nov., a novel bacterium in the family Hymenobacteraceae, isolated from desert soil

A novel Gram-stain-negative, aerobic, oxidase-positive, catalase-positive, non-motile, short rod-shaped, red-pigmented strain, designated as SYSU D00434T, was isolated from a dry sandy soil sample collected from the Gurbantunggut desert in Xinjiang, north-west PR China. Strain SYSU D00434T was found to grow at 4–37 °C (optimum, 28–30 °C), pH 6.0–8.0 (optimum, pH 7.0) and with 0–1.5 % (w/v) NaCl (optimum, 0–0.5 %). The predominant respiratory quinone was MK-7 and the major fatty acids (>10 %) were C16 : 1  ω5c, iso-C15 : 0, summed feature 3 (C16 : 1  ω6c and/or C16 : 1  ω7c) and summed feature 4 (anteiso-C17 : 1 B and/or iso-C17 : 1 I). The polar lipids consisted of phosphatidylethanolamine, two unidentified polar lipids, two unidentified aminolipids, two unidentified phospholipids and two unidentified glycolipids. The genomic DNA G+C content of strain SYSU D00434T was 50.6 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYSU D00434T belonged to the family Hymenobacteraceae , and shared a sequence similarity of less than 94.6 % to all validly named taxa. Based on the phenotypic, phylogenetic and chemotaxonomic properties, strain D00434T is proposed to represent a new species of a new genus, named Sabulibacter ruber gen. nov., sp. nov., within the family Hymenobacteraceae . The type strain is SYSU D00434T (=CGMCC 1.18624T=KCTC 82276T=MCCC 1K04975T).

A novel organic carbon accumulation mechanism in croplands in the Yellow River Delta, China

The trends and mechanisms of organic carbon changes in coastal delta croplands are not yet clear due to the complexity physicochemical processes in soil. In this study, combing powder x-ray diffraction (XRD), microbial analysis, and density functional theory in quantum mechanics, we proposed a novel mechanism underlying OC accumulation. We investigated changes of three kinds of organic carbon (OC)-dissolved organic carbon (DOC), light fraction organic carbon (LFOC), and heavy fraction organic carbon (HFOC) in the Yellow River Delta croplands. We found that HFOC, dominant in coastal delta cropland soil, formed at different ages and its density increased with increasing reclamation time. Yet, DOC and LFOC had no significant increase or decrease tendency. Moreover, in coastal delta croplands, HFOC accumulation might be a complex progress, including the loss of indigenous OC and the accumulation of newly input OC. Based on these results, we proposed that although root exudative DOC (organic acids) could cause the indigenous OC loss by forming a specific microbial community, it still was a source of HFOC and promoted the OC accumulation. More importantly, based on density functional theory, we verified that these root exudative organic acids could adsorb on SiO₂ together with crystalline Fe oxides (Fe_c) to form aggregates. The finding could explain the phenomenon that the XRD results showed samples were compounds of SiO₂, Fe_c, and OC and the accumulation of HFOC in coastal delta croplands. By revealing a new OC accumulation mechanism in coastal delta croplands, this study provides novel insights into the mechanism of OC dynamics in coastal delta croplands and the global carbon budget.

Adhaeribacter terrigena sp. nov., Isolated from Korean Soil

A bacterial strain, designated BT258^T, was isolated from a soil sample collected from Uijeongbu-si, Gyeong-do Province, Republic of Korea. Cells were Gram stain negative, aerobic, rod shaped, motile by gliding, and formed light pink-pigmented colonies on agar plates. Growth of the isolate was observed at 10-37 °C and pH 6-7. A 16S rRNA gene sequence analysis revealed that strain BT258^T is a member of the genus Adhaeribacter in the family Hymenobacteraceae and had the highest sequence similarity with 'Adhaeribacter soli' MA2^T (97.1%), Adhaeribacter terreus DNG6^T (96.6%), and Adhaeribacter terrae HY02^T (96.5%). The predominant respiratory quinone of the isolate was MK-7, the main polar lipid was phosphatidylethanolamine, and the major fatty acids were C_15:0 iso (37.7%), summed feature 4 (C_17:1 anteiso B/iso-C_17:1 I; 16.8%), and C_16:0 (10.3%). The draft genome of strain BT258^T had a whole length of 4,974,022 bp and DNA G + C content of 46.0 mol%. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between the novel isolate and 'Adhaeribacter soli' and seven other Adhaeribacter species ranged from 17.9 to 22.7% and 69.7 to 77.9%, respectively. On the basis of its phenotypic properties, genotypic distinctiveness, and chemotaxonomic features, strain BT258^T represents a novel species in the genus Adhaeribacter, for which the name Adhaeribacter terrigena sp. nov. is proposed. The type strain is BT258^T (= KCTC 72409 ^T = JCM 34303 ^T).

Adhaeribacter radiodurans sp. nov., isolated from the rhizospheric soil of Elymus tsukushiensis, a plant native to the Dokdo Islands, Republic of Korea

KUDC8001^T was isolated from the rhizosperic soil of Elymus tsukushiensis in the Dokdo Islands, Republic of Korea. Strain KUDC8001^T was Gram-stain-negative, non-motile and rod-shaped. KUDC8001^T was catalase- and oxidase-positive. This strain is capable of growing at 4-37 °C and pH 7.0-8.0 and exhibited optimal growth at 25 °C and pH 7.0. It could be grown in R2A, nutrient agar and ISP2 agar plates. The cell width ranged from 0.7 to 1.0 µm, and length ranged from 2.5 to 5.5 µm. The genomic G+C content was 40.8 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that the strain KUDC8001^T belongs to the genus Adhaeribacter, which is most closely related to the strain A. pallidiroseus HMF7616^T (97.5%). The DNA relatedness of KUDC8001^T with the type strains of A. pallidiroseus HMF7616^T, A. swui 17 mud1-7^T and A. arboris HMF7605^T was ≤80.3 % based on average nucleotide identity calculations and ≤86.9 % based on average amino acid identity calculations. In silico DNA-DNA hybridization values of the strain KUDC8001^T with the most closely related strains were 22.1, 24.0 and 24.4 %. Based on its phenotypic, phylogenetic, genetic and chemotaxonomic features, the strain KUDC8001^T should be considered as a novel species in the genus Adhaeribacter, for which we have proposed the name Adhaeribacter radiodurans sp. nov. The type strain is KUDC8001^T (=KCTC 82078^T=CGMCC 1.18475^T).

Adhaeribacter arboris sp. nov., and Adhaeribacter pallidiroseus sp. nov., novel bacteria isolated from birch tree (Betula platyphylla)

Two Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strains, designated as HMF7605T and HMF7616T, were isolated from birch tree, in Yong-in, Republic of Korea. Strains HMF7605T and HMF7616T exhibited the highest 16S rRNA gene sequence similarities of 95.9 and 97.5 % to Adhaeribacter swui 17mud1-7T, 97.9 % between themselves. The values of average nucleotide identity and in silico DNA–DNA hybridization between strains HMF7605T and HMF7616T were 77.6 and 22.0 %, respectively. Phylogenetic analysis of the 16S rRNA gene sequences of the two strains revealed that they belonged to the genus Adhaeribacter within the family Hymenobacteraceae . The predominant fatty acids of both strains were iso-C15 : 0, summed feature 3 (comprising C16 : 1  ω7c and/or C16 : 1  ω6c), C16 : 1  ω5c and summed feature 4 (comprising iso-C17 : 1 I and/or anteiso-C17 : 1 B). The both strains contained menaquinone-7 as the only isoprenoid quinone. The major polar lipid profiles of the two strains were similar with phosphatidylethanolamine, one unidentified aminophosphoglycolipid, one unidentified glycolipid and three unidentified polar lipids. The DNA G+C contents of strains HMF7605T and HMF7616T were 42.0 and 42.8 mol%, respectively. Based on the results of the phenotypic, genotypic, chemotaxonomic and phylogenetic investigation, two novel species, Adhaeribacter arboris sp. nov. and Adhaeribacter pallidiroseus sp. nov. are proposed. The type strains are HMF7605T (=KCTC 62465T=NBRC 113228T) and HMF7616T (=KCTC 62466T=NBRC 113229T), respectively.

Adhaeribacter rhizoryzae sp. nov., a fibrillar matrix-producing bacterium isolated from the rhizosphere of rice plant

A novel fibrillar matrix-producing, rod-shaped, red–orange, asporogenous, aerobic bacterium, designated DK36T, was isolated from roots of a rice plant in the Ilsan region near Dongguk University, South Korea. Cells of strain DK36T were Gram-stain-negative and motile by means of gliding. The temperature and pH ranges for growth were 7–35 °C (optimum: 30 °C) and pH 5–10 (optimum: pH 7.0). The strain did not require NaCl for growth but tolerated up to 8 % (w/v) NaCl. Phylogenetic anlaysis of the 16S rRNA gene sequence revealed that DK36T formed a monophyletic clade with Adhaeribacter aerophilus 6425 S-25T, Adhaeribacter aerolatus 6515 J-31T and Adhaeribacter swui 17mud1-7T with sequence similarities of 96.3, 95.5 and 95.2%, respectively. The average nucleotide identity and in silico DNA–DNA hybridization values of strain DK36T with the most closely related strains whose whole genomes are publicly available were 72.5–83.6% and 19–28 %, respectively. The strain showed the typical chemotaxonomic characteristics of the genus Adhaeribacter , with the presence of menaquinone MK-7 as the respiratory quinone, and C16 : 1ω5c, iso-C15 : 0 and summed feature 4 (composed of iso-C17 : 1 I/anteiso-C17 : 1 B) as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, one unidentified aminophosphoglycolipid, one unidentified phospholipid, two unidentified aminolipids and five unidentified polar lipids. The genomic DNA G+C content based on the draft genome sequence was 43.4 mol%. The results of physiological and biochemical tests and 16S rRNA gene sequence analysis clearly revealed that strain DK36T represents a novel species of the genus Adhaeribacter , for which the name Adhaeribacter rhizoryzae sp. nov. is proposed. The type strain is DK36T (=KACC 19902T=NBRC 113689T).

Adhaeribacter soli sp. nov., a bacterium isolated from soil in Korea

Strain MA2^T was isolated from a soil sample from Gijang-gun, Busan in Korea. The strain, a Gram-stain-negative aerobic bacterium, is non-motile, ovoid- or rod-shaped, catalase- and oxidase-positive, and grows at NaCl concentrations 1% (w/v), at 15-30 °C (optimum 25 °C) and at pH 6-8.5 (optimum pH 7.5). The 16S rRNA gene sequence indicates that it belongs to the genus Adhaeribacter in the family Hymenobacteraceae. Phylogenetically, its closest relatives are Adhaeribacter terrae HY02^T and Adhaeribacter terreus DNG6^T, to which the strain shows 16S rRNA gene sequence similarity values of 96.6 and 96.0%, respectively. The major fatty acids (> 5% of the total fatty acids) of strain MA2^T are C_15:0 iso, C_15:0 iso-G and summed feature 4 (anteiso-C_17:1 B and/or iso-C_17:1 I). The only detected isoprenoid quinone of strain MA2^T is MK-7. The major polar lipid was phosphatidylethanolamine. The draft genome sequence of strain MA2^T has a size of 4.9 Mkb. The genomic DNA G + C content was 46.9 mol%. Based on the phylogenetic, genotypic, phenotypic and chemotaxonomic data, the strain represents a novel species of the genus Adhaeribacter, for which the name Adhaeribacter soli sp. nov. is proposed. Strain MA2^T (= KCTC 72630^T = NBRC 114192^T) is the type strain.

Microbial community types and signature-like soil bacterial patterns from fortified prehistoric hills of Thuringia (Germany)

16S rRNA profiling has been applied for the investigation of bacterial communities of surface soil samples from forest-covered areas of ten prehistorical ramparts from different parts of Thuringia. Besides the majority bacterial types that are present in all samples, there could be identified bacteria that are highly abundant in some places and absent or low abundant in others. These differences are mainly related to the acidity of substrate and distinguish the communities of lime stone hills from soils of sand/quartzite and basalt hills. Minority components of bacterial communities show partially large differences that cannot be explained by the pH of the soil or incidental effects, only. They reflect certain relations between the communities of different places and could be regarded as a kind of signature-like patterns. Such relations had also been found in a comparison of the data from ramparts with formerly studied 16S rRNA profiling from an iron-age burial field. The observations are supporting the idea that a part of the components of bacterial communities from soil samples reflect their ecological history and can be understood as the “ecological memory” of a place. Probably such memory effects can date back to prehistoric times and might assist in future interpretations of archaeological findings on the prehistoric use of a place, on the one hand. On the other hand, the genetic profiling of soils of prehistoric places contributes to the evaluation of anthropogenic effects on the development of local soil bacterial diversity.

Metabolic regulation of the maize rhizobiome by benzoxazinoids

The rhizobiome is an important regulator of plant growth and health. Plants shape their rhizobiome communities through production and release of primary and secondary root metabolites. Benzoxazinoids (BXs) are common tryptophan-derived secondary metabolites in grasses that regulate belowground and aboveground biotic interactions. In addition to their biocidal activity, BXs can regulate plant–biotic interactions as semiochemicals or within-plant defence signals. However, the full extent and mechanisms by which BXs shape the root-associated microbiome has remained largely unexplored. Here, we have taken a global approach to examine the regulatory activity of BXs on the maize root metabolome and associated bacterial and fungal communities. Using untargeted mass spectrometry analysis in combination with prokaryotic and fungal amplicon sequencing, we compared the impacts of three genetic mutations in different steps in the BX pathway. We show that BXs regulate global root metabolism and concurrently influence the rhizobiome in a root type-dependent manner. Correlation analysis between BX-controlled root metabolites and bacterial taxa suggested a dominant role for BX-dependent metabolites, particularly flavonoids, in constraining a range of soil microbial taxa, while stimulating methylophilic bacteria. Our study supports a multilateral model by which BXs control root–microbe interactions via a global regulatory function in root secondary metabolism.

Botryobacter ruber gen. nov., sp. nov., a novel member of the family Hymenobacteraceae

Strain SYSU D60016^T, a rod-shaped bacterium that tends to form clusters, was isolated from a soil sample collected from the Gurbantunggut desert, China. Cells were Gram-stain-negative, catalase-negative and oxidase-positive. The 16S rRNA gene sequence of strain SYSU D60016^T shared less than 94 % sequence identity with members of the family Hymenobacteraceae. The strain exhibited growth at 15-50 °C, pH 6-8 and in the presence of up to 3 % (w/v) NaCl. Its chemotaxonomic features included MK-7 as the respiratory menaquinone, iso-C15 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) as major cellular fatty acids and phosphatidylethanolamine as the main polar lipid. The DNA G+C content was determined to be 50.1 % (genome). Analyses of the phylogenetic data and differences in the chemotaxonomic and biochemical features from related genera in the family Hymenobacteraceae indicated that strain SYSU D60016^T merits representation of a novel species of a novel genus in the family Hymenobacteraceae. The name Botryobacter ruber gen. nov., sp. nov. is, therefore, proposed to represent the phylogenetic position of strain SYSU D60016^T in the family Hymenobacteraceae. The type strain of the proposed new taxon is SYSU D60016^T (=KCTC 52794^T=NBRC 112957^T).

Hymenobacter crusticola sp. nov., isolated from biological soil crust

A Gram-stain-negative, aerobic, light-pink, short rod-shaped, non-spore-forming bacterial strain was isolated from biological soil crust sampled in the Hopq Desert, Inner Mongolia, China, designated MIMBbqt21^T. The G+C content of the genomic DNA was 55.1 mol%. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain MIMBbqt21^T belonged to the genus Hymenobacter and had the highest sequence similarity to Hymenobacter cavernaeK1E01-27^T (94.35 %). Cell growth could be observed at 4-29 °C (optimum, 24 °C), pH of 6.0-8.6 (optimum, 6.0) and in the presence of 1 % (w/v) NaCl (optimum, 0 %). The major fatty acids of strain MIMBbqt21^T were iso-C15 : 0, C16 : 1ω5c and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c). The main polar lipids were phosphatidylethanolamine, five unidentified aminophospholipids, an unidentified glycolipid and four unidentified polar lipids. The sole respiratory quinone was menaquinone MK-7. Based on the results of the phylogenetic, chemotaxonomic and phenotypic studies, strain MIMBbqt21^T could be distinguished from all known Hymenobacter species and represents a novel species, for which the name Hymenobactercrusticola sp. nov. is proposed. The type strain is MIMBbqt21^T (=MCCC 1K01312^T=KCTC 42804^T).

Antibacterial activity of aquatic gliding bacteria

The study aimed to screen and isolate strains of freshwater aquatic gliding bacteria, and to investigate their antibacterial activity against seven common pathogenic bacteria. Submerged specimens were collected and isolated for aquatic gliding bacteria using four different isolation media (DW, MA, SAP2, and Vy/2). Gliding bacteria identification was performed by 16S rRNA gene sequencing and phylogenetic analysis. Crude extracts were obtained by methanol extraction. Antibacterial activity against seven pathogenic bacteria was examined by agar-well diffusion assay. Five strains of aquatic gliding bacteria including RPD001, RPD008, RPD018, RPD027 and RPD049 were isolated. Each submerged biofilm and plastic specimen provided two isolates of gliding bacteria, whereas plant debris gave only one isolate. Two strains of gliding bacteria were obtained from each DW and Vy/2 isolation medium, while one strain was obtained from the SAP2 medium. Gliding bacteria strains RPD001, RPD008 and RPD018 were identified as Flavobacterium anhuiense with 96, 82 and 96 % similarity, respectively. Strains RPD049 and RPD027 were identified as F. johnsoniae and Lysobacter brunescens, respectively, with similarity equal to 96 %. Only crude extract obtained from RPD001 inhibited growth of Listeria monocytogenes (MIC 150 µg/ml), Staphylococcus aureus (MIC 75 µg/ml) and Vibrio cholerae (MIC 300 µg/ml), but showed weak inhibitory effect on Salmonella typhimurium (MIC > 300 µg/ml). Gliding bacterium strain RPD008 should be considered to a novel genus separate from Flavobacterium due to its low similarity value. Crude extract produced by RPD001 showed potential for development as a broad antibiotic agent.

A primary assessment of the endophytic bacterial community in a xerophilous moss (Grimmia montana) using molecular method and cultivated isolates

Investigating the endophytic bacterial community in special moss species is fundamental to understanding the microbial-plant interactions and discovering the bacteria with stresses tolerance. Thus, the community structure of endophytic bacteria in the xerophilous moss Grimmia montana were estimated using a 16S rDNA library and traditional cultivation methods. In total, 212 sequences derived from the 16S rDNA library were used to assess the bacterial diversity. Sequence alignment showed that the endophytes were assigned to 54 genera in 4 phyla (Proteobacteria, Firmicutes, Actinobacteria and Cytophaga/Flexibacter/Bacteroids). Of them, the dominant phyla were Proteobacteria (45.9%) and Firmicutes (27.6%), the most abundant genera included Acinetobacter, Aeromonas, Enterobacter, Leclercia, Microvirga, Pseudomonas, Rhizobium, Planococcus, Paenisporosarcina and Planomicrobium. In addition, a total of 14 species belonging to 8 genera in 3 phyla (Proteobacteria, Firmicutes, Actinobacteria) were isolated, Curtobacterium, Massilia, Pseudomonas and Sphingomonas were the dominant genera. Although some of the genera isolated were inconsistent with those detected by molecular method, both of two methods proved that many different endophytic bacteria coexist in G. montana. According to the potential functional analyses of these bacteria, some species are known to have possible beneficial effects on hosts, but whether this is the case in G. montana needs to be confirmed.

New approaches for isolation of previously uncultivated oral bacteria

A significant number of microorganisms from the human oral cavity remain uncultivated. This is a major impediment to the study of human health since some of the uncultivated species may be involved in a variety of systemic diseases. We used a range of innovations previously developed to cultivate microorganisms from the human oral cavity, focusing on anaerobic species. These innovations include (i) in vivo cultivation to specifically enrich for species actively growing in the oral cavity (the "minitrap" method), (ii) single-cell long-term cultivation to minimize the effect of fast-growing microorganisms, and (iii) modifications of conventional enrichment techniques, using media that did not contain sugar, including glucose. To enable cultivation of obligate anaerobes, we maintained strict anaerobic conditions in most of our cultivation experiments. We report that, on a per cell basis, the most successful recovery was achieved using minitrap enrichment (11%), followed by single-cell cultivation (3%) and conventional plating (1%). Taxonomically, the richest collection was obtained using the single-cell cultivation method, followed by minitrap and conventional enrichment, comprising representatives of 13, 9, and 4 genera, respectively. Interestingly, no single species was isolated by all three methods, indicating method complementarity. An important result is the isolation and maintenance in pure culture of 10 strains previously only known by their molecular signatures, as well as representatives of what are likely to be three new microbial genera. We conclude that the ensemble of new methods we introduced will likely help close the gap between cultivated and uncultivated species from the human oral cavity.

Siphonobacter aquaeclarae gen. nov., sp. nov., a novel member of the family ‘Flexibacteraceae’, phylum Bacteroidetes

A Gram-negative bacterium, designated P2T, was isolated from the biofilm developed on the inner surface of an ultrapure cooling water system in a Hungarian power plant and was characterized by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain P2T was affiliated with the family ‘Flexibacteraceae’ in the phylum Bacteroidetes. Its closest relative was Flectobacillus lacus CL-GP79T (88.7 % 16S rRNA gene sequence similarity) followed by Arcicella rosea TW5T (86.5 %), Arcicella aquatica NO-502T (86.4 %), Flectobacillus roseus GFA-11T (86.3 %) and Flectobacillus major DSM 103T (85.4 %). Cells of strain P2T were facultatively anaerobic, non-motile rods. The major fatty acids were C16 : 1 ω5c (42.5 %), iso-C15 : 0 2-OH (17.2 %), iso-C17 : 0 3-OH (16.1 %) and iso-C15 : 0 (8.5 %). The major menaquinone was MK-7 and the predominant polar lipid was phosphatidylethanolamine. The DNA G+C content was 54.5 mol%. Thus, the phenotypic and genotypic analyses clearly showed that strain P2T is considerably different from members of other genera in the family ‘Flexibacteraceae’. Based on these results, it is concluded that strain P2T represents a novel species in a new genus, for which the name Siphonobacter aquaeclarae gen. nov., sp. nov. is proposed, with type strain P2T (=DSM 21668T =NCAIM B 02328T).

Adhaeribacter aerophilus sp. nov., Adhaeribacter aerolatus sp. nov. and Segetibacter aerophilus sp. nov., isolated from air samples

Three bacterial isolates from air samples in Korea, designated strains 6424S-25(T), 6515J-31(T) and 6424S-61(T), were characterized using a polyphasic approach. The cells were strictly aerobic, Gram-stain-negative, non-motile, non-spore-forming and rod-shaped. Phylogenetic analysis of their 16S rRNA gene sequences revealed a clear affiliation with the phylum Bacteroidetes. Strains 6424S-25(T) and 6515J-31(T) showed 16S rRNA gene sequence similarities of 92.7-94.8 % to type strains of recognized species of the genus Adhaeribacter and strain 6424S-61(T) was closely related to Segetibacter koreensis Gsoil 664(T) (93.9 % similarity). The G+C contents of the DNA of strains 6424S-25(T), 6515J-31(T) and 6424S-61(T) were 44.5, 43.9 and 38.4 mol%, respectively. Major fatty acids of strains 6424S-25(T) and 6515J-31(T) were summed feature 4 (iso-C₁₇:₁ I and/or anteiso-C₁₇ :₁ B), iso-C₁₅:₀ and C₁₆:₁ω5c. The fatty acid content of strain 6424S-61(T) mainly comprised iso-C₁₅ :₁ G and iso-C₁₅:₀. Comparative analysis of phenotypic and phylogenetic traits indicated that strains 6424S-25(T) and 6515J-31(T) represented two novel species of the genus Adhaeribacter and that strain 6424S-61(T) should be considered as a novel species of the genus Segetibacter. The names Adhaeribacter aerophilus sp. nov. (type strain 6424S-25(T) =KACC 14118(T) =NBRC 106134(T)), Adhaeribacter aerolatus sp. nov. (type strain 6515J-31(T) =KACC 14117(T) =NBRC 106133(T)) and Segetibacter aerophilus sp. nov. (type strain 6424S-61(T) =KACC 14119(T) =NBRC 106135(T)) are proposed for these organisms.

Effluviibacter roseus gen. nov., sp. nov., isolated from muddy water, belonging to the family "Flexibacteraceae"

A Gram-negative bacterial isolate (designated SRC-1(T)) was isolated from an occasional drainage system and characterized by a polyphasic approach to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences affiliated strain SRC-1(T) with the family "Flexibacteraceae" of the phylum Bacteroidetes. It showed greatest sequence similarity to Pontibacter actiniarum KMM 6156(T) (95.5 %) followed by Adhaeribacter aquaticus MBRG1.5(T) (89.0 %) and Hymenobacter roseosalivarius DSM 11622(T) (88.9 %), but it differed from these micro-organisms in many phenotypic characteristics. Strain SRC-1(T) was an obligate aerobe and its cells were non-motile, irregular rods. The major fatty acids included mainly unsaturated and hydroxy fatty acids, including 17 : 1 iso I/anteiso B (36.7 %), 15 : 0 iso (15.8 %) and 17 : 0 iso 3-OH (10.3 %), and the DNA G+C content was 59.5 mol%. From the phenotypic and genotypic analyses it was clear that strain SRC-1(T) was quite different from members other genera in the family '"Flexibacteraceae". Therefore we conclude that strain SRC-1(T) represents a novel genus, for which the name Effluviibacter gen. nov., containing a single species Effluviibacter roseus sp. nov., is proposed. The type species of the genus is Effluviibacter roseus, the type strain of which is strain SRC-1(T) (=MTCC 7260(T)=DSM 17521(T)).

Microbial ecology of drinking water distribution systems

The supply of clean drinking water is a major, and relatively recent, public health milestone. Control of microbial growth in drinking water distribution systems, often achieved through the addition of disinfectants, is essential to limiting waterborne illness, particularly in immunocompromised subpopulations. Recent inquiries into the microbial ecology of distribution systems have found that pathogen resistance to chlorination is affected by microbial community diversity and interspecies relationships. Research indicates that multispecies biofilms are generally more resistant to disinfection than single-species biofilms. Other recent findings are the increased survival of the bacterial pathogen Legionella pneumophila when present inside its protozoan host Hartmannella vermiformis and the depletion of chloramine disinfectant residuals by nitrifying bacteria, leading to increased overall microbial growth. Interactions such as these are unaccounted for in current disinfection models. An understanding of the microbial ecology of distribution systems is necessary to design innovative and effective control strategies that will ensure safe and high-quality drinking water.

Description of Fabibacter halotolerans gen. nov., sp. nov. and Roseivirga spongicola sp. nov., and reclassification of [Marinicola] seohaensis as Roseivirga seohaensis comb. nov

Bacterial strains UST030701-097T and UST030701-084T were isolated from a marine sponge in the Bahamas. Both strains were pink-pigmented, Gram-negative, strictly aerobic and chemo-organotrophic. Cells of strain UST030701-097T were short, curved rods with fast-gliding motility, whereas those of strain UST030701-084T were straight rods with a less rapid gliding motion. The two strains had MK-7 as the major respiratory quinone and did not produce flexirubin-type pigments. The DNA G+C contents of strains UST030701-097T and UST030701-084T were 42.5 and 43.7 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains belonged to the family ‘Flexibacteraceae’ of the phylum Bacteroidetes. 16S rRNA gene sequence similarity between strains UST030701-097T and UST030701-084T was 95.0 %; their closest relative was [Marinicola] seohaensis, with 93.3 % and 96.0 % sequence similarity, respectively. Phylogenetic tree topology indicated that the two strains belonged to the same lineage, but were on separate branches. Whilst strain UST030701-084T and [Marinicola] seohaensis were found on one branch, strain UST030701-097T was in another branch that had no species with validly published names. Based on the polyphasic taxonomic data obtained in the present study, we propose that strain UST030701-097T represents a novel genus and that strain UST030701-084T represents a novel species in the phylum Bacteroidetes. The genus Fabibacter gen. nov. is proposed, with strain UST030701-097T (=NRRL B-41220T=JCM 13334T) as the type strain of the type species, Fabibacter halotolerans sp. nov. Strain UST030701-084T (=NRRL B-41219T=JCM 13337T) is proposed as the type strain of Roseivirga spongicola sp. nov. In an earlier study, it was suggested that the genus Marinicola is a later heterotypic synonym of the genus Roseivirga. However, a formal proposal to reclassify [Marinicola] seohaensis, the only member of the genus Marinicola, has not yet been made. The results of phylogenetic analyses in this study support the reclassification of [Marinicola] seohaensis as Roseivirga seohaensis comb. nov.

Pontibacter actiniarum gen. nov., sp. nov., a novel member of the phylum ‘Bacteroidetes’, and proposal of Reichenbachiella gen. nov. as a replacement for the illegitimate prokaryotic generic name Reichenbachia Nedashkovskaya et al. 2003

The taxonomic position of a marine, gliding, pink-pigmented, aerobic, heterotrophic and Gram-negative bacterium was established using a polyphasic approach. 16S rRNA gene sequence analysis indicated that the strain was a member of the phylum ‘Bacteroidetes’ in which it occupied a separate lineage. The predominant cellular fatty acids were C15 : 0 iso, C17 : 0 iso 3-OH, summed feature 3 and summed feature 4. The DNA G+C content was 48·7 mol%. Phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analyses strongly support the assignment of the newly isolated bacterium as a member of a novel genus and species, for which the name Pontibacter actiniarum gen. nov., sp. nov. is proposed. The type strain is KMM 6156T (=KCTC 12367T=LMG 23027T). It is also proposed that the illegitimate names Reichenbachia and Reichenbachia agariperforans are replaced with Reichenbachiella and Reichenbachiella agariperforans, respectively.