Arcticiflavibacter luteus gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from intertidal sand

Red Sea Atlas of Coral-Associated Bacteria Highlights Common Microbiome Members and Their Distribution across Environmental Gradients-A Systematic Review

The Red Sea is a suitable model for studying coral reefs under climate change due to its strong environmental gradient that provides a window into future global warming scenarios. For instance, corals in the southern Red Sea thrive at temperatures predicted to occur at the end of the century in other biogeographic regions. Corals in the Red Sea thrive under contrasting thermal and environmental regimes along their latitudinal gradient. Because microbial communities associated with corals contribute to host physiology, we conducted a systematic review of the known diversity of Red Sea coral-associated bacteria, considering geographic location and host species. Our assessment comprises 54 studies of 67 coral host species employing cultivation-dependent and cultivation-independent techniques. Most studies have been conducted in the central and northern Red Sea, while the southern and western regions remain largely unexplored. Our data also show that, despite the high diversity of corals in the Red Sea, the most studied corals were Pocillopora verrucosa, Dipsastraea spp., Pleuractis granulosa, and Stylophora pistillata. Microbial diversity was dominated by bacteria from the class Gammaproteobacteria, while the most frequently occurring bacterial families included Rhodobacteraceae and Vibrionaceae. We also identified bacterial families exclusively associated with each of the studied coral orders: Scleractinia (n = 125), Alcyonacea (n = 7), and Capitata (n = 2). This review encompasses 20 years of research in the Red Sea, providing a baseline compendium for coral-associated bacterial diversity.

Description of Aureibaculum luteum sp. nov. and Aureibaculum flavum sp. nov. isolated from Antarctic intertidal sediments

Two Gram-stain-negative, aerobic, non-motile, and rod-shaped bacterial strains, designated SM1352^T and A20^T, were isolated from intertidal sediments collected from King George Island, Antarctic. They shared 99.8% 16S rRNA gene sequence similarity with each other and had the highest sequence similarity of 98.1% to type strain of Aureibaculum marinum but < 93.4% sequence similarity to those of other known bacterial species. The genomes of strains SM1352^T and A20^T consisted of 5,108,092 bp and 4,772,071 bp, respectively, with the G + C contents both being 32.0%. They respectively encoded 4360 (including 37 tRNAs and 6 rRNAs) and 4032 (including 36 tRNAs and 5 rRNAs) genes. In the phylogenetic trees based on 16S rRNA gene and single-copy orthologous clusters (OCs), both strains clustered with Aureibaculum marinum and together formed a separate branch within the family Flavobacteriaceae. The ANI and DDH values between the two strains and Aureibaculum marinum BH-SD17^T were all below the thresholds for species delineation. The major cellular fatty acids (> 10%) of the two strains included iso-C_15:0, iso-C_15:1 G, iso-C_17:0 3-OH. Their polar lipids predominantly included phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified aminolipid, and two unidentified lipids. Genomic comparison revealed that both strains possessed much more glycoside hydrolases and sulfatase-rich polysaccharide utilization loci (PULs) than Aureibaculum marinum BH-SD17^T. Based on the above polyphasic evidences, strains SM1352^T and A20^T represent two novel species within the genus Aureibaculum, for which the names Aureibaculum luteum sp. nov. and Aureibaculum flavum sp. nov. are proposed. The type strains are SM1352^T (= CCTCC AB 2014243 ^T = JCM 30335 ^T) and A20^T (= CCTCC AB 2020370 ^T = KCTC 82503 ^T), respectively.

Extremophiles in Soil Communities of Former Copper Mining Sites of the East Harz Region (Germany) Reflected by Re-Analyzed 16S rRNA Data

The east and southeast rim of Harz mountains (Germany) are marked by a high density of former copper mining places dating back from the late 20th century to the middle age. A set of 18 soil samples from pre- and early industrial mining places and one sample from an industrial mine dump have been selected for investigation by 16S rRNA and compared with six samples from non-mining areas. Although most of the soil samples from the old mines show pH values around 7, RNA profiling reflects many operational taxonomical units (OTUs) belonging to acidophilic genera. For some of these OTUs, similarities were found with their abundances in the comparative samples, while others show significant differences. In addition to pH-dependent bacteria, thermophilic, psychrophilic, and halophilic types were observed. Among these OTUs, several DNA sequences are related to bacteria which are reported to show the ability to metabolize special substrates. Some OTUs absent in comparative samples from limestone substrates, among them Thaumarchaeota were present in the soil group from ancient mines with pH > 7. In contrast, acidophilic types have been found in a sample from a copper slag deposit, e.g., the polymer degrading bacterium Granulicella and Acidicaldus, which is thermophilic, too. Soil samples of the group of pre-industrial mines supplied some less abundant, interesting OTUs as the polymer-degrading Povalibacter and the halophilic Lewinella and Halobacteriovorax. A particularly high number of bacteria (OTUs) which had not been detected in other samples were found at an industrial copper mine dump, among them many halophilic and psychrophilic types. In summary, the results show that soil samples from the ancient copper mining places contain soil bacterial communities that could be a promising source in the search for microorganisms with valuable metabolic capabilities.

Flavihalobacter algicola gen. nov. sp. nov., a member of the family Flavobacteriaceae with alginate-degradation activity, isolated from marine alga Saccharina japonica

A Gram-stain-negative, aerobic, yellow, non-motile, rod-shaped and alginate-degrading bacterium, designated Dm15^T, was isolated from marine alga collected in Weihai, PR China. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Dm15^T represents a distinct line of the family Flavobacteriaceae. Strain Dm15^T had the highest 16S rRNA gene sequence similarity to its closest phylogenetic neighbour Arcticiflavibacter luteus (96.7 %) and 93.7-96.4 % sequence similarity to other phylogenetic neighbours (Bizionia paragorgiae, Winogradskyella thalassocola, Ichthyenterobacterium magnum, Psychroserpens burtonensis and Arcticiflavibacter luteus) in the family Flavobacteriaceae. The novel isolate was able to grow at 10-40 °C (optimum, 30-33 °C), pH 7.0-9.0 (optimum, pH 7.0-7.5) and with 0.5-6.0 % NaCl (optimum 2.0-3.0 %, w/v). It could grow at 40 °C, and degrade alginate and cellulose, which were different from the neighbour genera. The draft genome consisted of 3395 genes with a total length of 3 798 431 bp and 34.1mol% G+C content. Especially, there were some specific genes coding for cellulase and alginate lyase, which provided a basis for the above phenotypic characteristics. The strain's genome sequence showed 71.1-80.2 % average amino acid identity values and 71.8-77.7 % average nucleotide identity values compared to the type strains of related genera within the family Flavobacteriaceae. It shared digital DNA-DNA hybridization identity of 19.8 and 20.9 % with I. magnum and A. luteus, respectively. The sole menaquinone was MK-6. The major fatty acids were iso-C_15 : 0 and iso-C_15 : 1 G. The polar lipids included six unidentified polar lipids, four unidentified aminolipids and phosphatidylethanolamine. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain Dm15^T represents a novel species of a new genus in the family Flavobacteriaceae, phylum Bacteroidetes, for which the name Flavihalobacter algicola gen. nov., sp. nov. is proposed. The type strain is Dm15^T (KCTC 42256^T=CICC 23815^T).

Pseudobizionia ponticola gen. nov., sp. nov., isolated from seawater

A Gram-stain-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, designated MM-14^T, was isolated from seawater sampled from the Yellow Sea in the Republic of Korea and its taxonomic position was investigated using a polyphasic approach. Strain MM-14^T grew optimally at 30 °C and in the presence of approximately 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain MM-14^T clustered with the type strain of Hanstruepera neustonica. The novel strain exhibited a 16S rRNA gene sequence similarity value of 96.06 % to the type strain of H. neustonica, but higher 16S rRNA gene sequence similarity values (96.13-96.69 %) to the type strains of Bizionia echini, Bizionia hallyeonensis and Bizionia psychrotolerans. Strain MM-14^T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C content of strain MM-14^T was 34.6 mol%. The phylogenetic and chemotaxonomic data and other phenotypic properties revealed that strain MM-14^T constitutes a new genus and species within the family Flavobacteriaceae of the phylum Bacteroidetes, for which the name Pseudobizionia ponticola gen. nov., sp. nov. is proposed. The type strain of Pseudobizionia ponticola is MM-14^T (=KACC 19434^T=KCTC 62139^T=NBRC 113019^T).

Changchengzhania lutea gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from Antarctic intertidal sediment

A Gram-negative, aerobic, yellow pigmented, non-flagellated, non-gliding, rod-shaped bacterial strain, designated SM1355^T, was isolated from Antarctic intertidal sediment collected near the Chinese Antarctic Great Wall Station. The strain grew at 4-35 °C and with 0.5-7.0 % (w/v) NaCl. It hydrolysed aesculin but didn't reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1355^T formed a distinct phylogenetic lineage within the family Flavobacteriaceae, sharing the highest 16S rRNA gene sequence similarity with Flaviramulus ichthyoenteri (96.3 %) and fairly high sequence similarities (95.0-96.0 %) with over 20 recognized species in eight genera of the family Flavobacteriaceae. The predominant fatty acids were anteiso-C15 : 0, iso-C15 : 0 and iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine and one unidentified lipid. The genomic DNA G+C content of strain SM1355^T was 36.2 mol%. Based on the results of the polyphasic characterization for strain SM1355^T, it is identified as the representative of a novel species in a new genus of the family Flavobacteriaceae, for which the name Changchengzhania lutea gen. nov., sp. nov. is proposed. The type strain of Changchengzhania lutea is SM1355^T (=JCM 30336^T=CCTCC AB 2014246^T).