Tamlana sedimentorum sp. nov., isolated from shallow sand sediments of the Sea of Japan

Tamlana flava sp. nov., isolated from mangrove sediment and genome-based taxonomic analysis of the genus Tamlana

A novel yellow-coloured bacterial strain MA10T was isolated from mangrove sediment and subjected to polyphasic taxonomic identification. Strain MA10T was Gram-negative, rod-shaped, catalase-positive and oxidase-positive. Carotenoid pigment was present, and flexirubin-type pigment was absent. The 16S rRNA gene of strain MA10T had the highest sequence similarity with Tamlana crocina HST1-43T of 94.5%. The genome size was 3.77 Mbp with a genomic G+C content of 36.3%. The phylogenetic analysis of the 16S rRNA gene sequence and whole-genome sequence showed that strain MA10T belonged to the genus Tamlana of the family Flavobacteriaceae and tightly clustered with T. crocina HST1-43T. The digital DNA-DNA hybridization value and average nucleotide identity value between strain MA10T and T. crocina HST1-43T were 20.4 and 76.7%, respectively. The major menaquinone was MK-6. The major fatty acids (>10 %) were iso-C15:0 (41.6%) and iso-C15:1 G (16.8%). The polar lipids consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. Based on the present polyphasic taxonomic study, strain MA10T was considered to represent a novel species of the genus Tamlana, for which the name Tamlana flava sp. nov. was proposed. The type strain was MA10T (=MCCC 1K09289T=KCTC 102321T). Additionally, the phylogeny of the 16S rRNA gene and whole-genome sequences found that the hitherto described nine species of the genus Tamlana and Algibacter onchidii presented polyphyletic clades, which could be divided into five different genera. The average amino acid identity value of 80% was chosen as the boundary of the five genera. Thus, except for the genus Tamlana, four novel genera named Allotamlana gen. nov., Cognatitamlana gen. nov., Neotamlana gen. nov. and Pseudotamlana gen. nov. were proposed. This study provided valuable taxonomic analysis of the genus Tamlana.

Tamlana laminarinivorans sp. nov. and Tamlana sargassicola sp. nov., two novel species isolated from Sargassum, show genomic and physiological adaptations for a Sargassum-associated lifestyle

The genus Tamlana from the Bacteroidota currently includes six validated species. Two strains designated PT2-4T and 62-3T were isolated from Sargassum abundant at the Pingtan island coast in the Fujian Province of China. 16S rRNA gene sequence analysis showed that the closest described relative of strains PT2-4T and 62-3T is Tamlana sedimentorum JCM 19808T with 98.40 and 97.98% sequence similarity, respectively. The 16S rRNA gene sequence similarity between strain PT2-4T and strain 62-3T was 98.68 %. Furthermore, the highest average nucleotide identity values were 87.34 and 88.97 % for strains PT2-4T and 62-3T, respectively. The highest DNA-DNA hybridization (DDH) value of strain PT2-4T was 35.2 % with strain 62-3T, while the DDH value of strain 62-3T was 37.7 % with T. sedimentorum JCM 19808T. Growth of strains PT2-4T and 62-3T occurs at 15-40 °C (optimum, 30 °C) with 0-4 % (w/v) NaCl (optimum 0-1 %). Strains PT2-4T and 62-3T can grow from pH 5.0 to 10.0 (optimum, pH 7.0). The major fatty acids of strains PT2-4T and 62-3T are iso-C15 : 0 and iso G-C15 : 1. MK-6 is the sole respiratory quinone. Genomic and physiological analyses of strains PT2-4T and 62-3T showed corresponding adaptive features. Significant adaptation to the growth environment of macroalgae includes the degradation of brown algae-derived diverse polysaccharides (alginate, laminarin and fucoidan). Notably, strain PT2-4T can utilize laminarin, fucoidan and alginate via specific carbohydrate-active enzymes encoded in polysaccharide utilization loci, rarely described for the genus Tamlana to date. Based on their distinct physiological characteristics and the traits of utilizing polysaccharides from Sargassum, strains PT2-4T and 62-3T are suggested to be classified into two novel species, Tamlana laminarinivorans sp. nov. and Tamlana sargassicola sp. nov. (type strain PT2-4T=MCCC 1K04427T=KCTC 92183T and type strain 62-3T=MCCC 1K04421T=KCTC 92182T).

Tamlana haliotis sp. nov., isolated from the gut of the abalone Haliotis rubra

A Gram-stain-negative, aerobic, non-motile, yellow-pigmented rod-shaped and alginate-degrading bacterium, designated B1N29^T, was isolated from the gut of the abalone Haliotis rubra obtained in Weihai, China. Strain B1N29^T was found to grow at 4-35 ℃ (optimum, 25 ℃), at pH 6.5-9.0 (optimum, 7.0-7.5) and in the presence of 0.5-9% (w/v) NaCl (optimum, 2%). Cells were positive for oxidase and catalase activity. The 16S rRNA-based phylogenetic analysis revealed that the nearest phylogenetic neighbors of strain B1N29^T were Tamlana carrageenivorans KCTC 62451^T (98.2%) and Tamlana agarivorans KCTC 22176^T (97.7%). Based on the phylogenomic analysis, the average nucleotide identity (ANI) values between strain B1N29^T and the neighbor strains were 79.2 and 79.0%, respectively; the digital DNA-DNA hybridization (dDDH) values between strain B1N29^T and its two closest neighbors were 22.8 and 23.0%, respectively. Menaquinone-6 (MK-6) was detected as the sole respiratory quinone. The dominant cellular fatty acids were iso-C_15:0, iso-C_17:0 3-OH, anteiso-C_15:0 and iso-C_15:1 G. The polar lipids included phosphatidylethanolamine, one aminophospholipid, seven aminolipids and five unidentified lipids. Based on the phylogenetic and phenotypic characteristics, strain B1N29^T is considered to represent a novel species of the genus Tamlana, for which the name Tamlana haliotis sp. nov. is proposed. The type strain is B1N29^T (= KCTC 72683^T = MCCC 1H00394^T).

Tamlana fucoidanivorans sp. nov., isolated from algae collected in China

A Gram-stain-negative, aerobic, non-motile and rod-shaped marine bacterium, CW2-9T, was isolated from algae collected from Fujian Province in PR China. 16S rRNA gene sequence analysis showed that this strain was affiliated with the genus Tamlana in the family Flavobacteriaceae of the class Flavobacteriia and was very similar to the type strain Tamlana sedimentorum MCCC 1A10799T (96.3 % sequence similarity). The whole genome of strain CW2-9T comprised 3 997 513 bp with a G+C content of 34.3 mol%. The average nucleotide identity value between strain CW2-9T and T. sedimentorum MCCC 1A10799T was 73.8 %. Growth was observed from 15 to 40 °C (optimum, 30 °C), at pH from pH 5.0 to 10.0 (pH 8.0) and in the presence of 0-4 % (w/v) NaCl (0-1 %). The major fatty acids (>10 % of the total) were iso-C15 : 0, iso G-C15 : 1, iso-C17 : 0 3-OH and anteiso-C15 : 0. The predominant menaquinone was MK-6. The combined phylogenetic, physiological and chemotaxonomic data indicate that strain CW2-9T represents a novel species in the genus Tamlana, for which the name Tamlana fucoidanivorans sp. nov. is proposed. The type strain is CW2-9T (=CICC 24749T=KCTC 72389T).

Insights into Red Sea Brine Pool Specialized Metabolism Gene Clusters Encoding Potential Metabolites for Biotechnological Applications and Extremophile Survival

The recent rise in antibiotic and chemotherapeutic resistance necessitates the search for novel drugs. Potential therapeutics can be produced by specialized metabolism gene clusters (SMGCs). We mined for SMGCs in metagenomic samples from Atlantis II Deep, Discovery Deep and Kebrit Deep Red Sea brine pools. Shotgun sequence assembly and secondary metabolite analysis shell (antiSMASH) screening unraveled 2751 Red Sea brine SMGCs, pertaining to 28 classes. Predicted categorization of the SMGC products included those (1) commonly abundant in microbes (saccharides, fatty acids, aryl polyenes, acyl-homoserine lactones), (2) with antibacterial and/or anticancer effects (terpenes, ribosomal peptides, non-ribosomal peptides, polyketides, phosphonates) and (3) with miscellaneous roles conferring adaptation to the environment/special structure/unknown function (polyunsaturated fatty acids, ectoine, ladderane, others). Saccharide (80.49%) and putative (7.46%) SMGCs were the most abundant. Selected Red Sea brine pool sites had distinct SMGC profiles, e.g., for bacteriocins and ectoine. Top promising candidates, SMs with pharmaceutical applications, were addressed. Prolific SM-producing phyla (Proteobacteria, Actinobacteria, Cyanobacteria), were ubiquitously detected. Sites harboring the largest numbers of bacterial and archaeal phyla, had the most SMGCs. Our results suggest that the Red Sea brine niche constitutes a rich biological mine, with the predicted SMs aiding extremophile survival and adaptation.

Tamlana carrageenivorans sp. nov., a carrageenan-degrading bacterium isolated from seawater

A Gram-stain-negative, aerobic, non-motile, rod-shaped, agarolytic and carrageenolytic bacterial strain, designated UJ94^T, was isolated from seawater of Uljin in the Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain UJ94^T shared sequence similarities of 98.4, 96.1 and 95.4 % with Tamlana agarivorans JW-26^T, Tamlana sedimentorum KMM 9545^T and Tamlana crocina HST1-43^T, respectively. Growth of strain UJ94^T was observed at 4-37 °C and pH 6.5-8.0 in the presence of 2-9 % (w/v) NaCl. The major fatty acids of strain UJ94^T were iso-C15 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and iso-C17 : 0 3-OH; MK-6 was the predominant menaquinone. Phosphatidylethanolamine, two unidentified aminolipids and five unidentified lipids were detected as major polar lipids. The whole circular genome comprised 4 116 543 bp and had a G+C content of 35.2 mol%. The ranges of average nucleotide identity and in silico DNA-DNA hybridization estimated by genome-to-genome distance were 90.6-74.2 % and 47.6-14.6 %, respectively, with the type strains of T. agarivorans and T. sedimentorum. The present polyphasic study, including phylogenetic, chemotaxonomic, biochemical and genomic data, suggested that strain UJ94^T represents a novel species of the genus Tamlana, for which the name Tamlana carrageenivorans sp. nov. is proposed. The type strain is UJ94^T (=KCTC 62451^T=NBRC 113234^T).

Thalassorhabdus aurantiaca gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from seawater in South Korea

A novel Gram-negative, orange pigmented, strictly aerobic bacterium, designated strain IP9^T, was isolated from seawater at the sea shore of Incheon Eulwang-ri beach, South Korea. Cells of strain IP9^T were observed to be straight or slightly curved rods and colonies to be round and convex. Strain IP9^T was found to be catalase and oxidase positive, and non-motile. Growth was observed in the temperature range of 10-37 °C (optimum at 30 °C), pH range of 6-10 (optimum at pH 7-8) and salt concentration range of 0-7% (w/v) NaCl (optimum at 0-1%). On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain IP9^T was found to be related to the members of the family Flavobacteriaceae, being closely related to Hwangdonia seohaensis KCTC 32177^T (95.3% sequence similarity). The DNA G + C content of the novel strain was determined to be 39.1 mol%. The major polar lipids were found to be phosphatidylethanolamine, three unidentified aminoglycolipids and two unidentified glycolipids. The major fatty acids (> 10%) were identified as iso-C_15:0 and iso-C_17:0 3-OH. The predominant quinone was found to be menaquinone 6 (MK-6). Based on the biochemical, phylogenetic and physiological data, we conclude that strain IP9^T (= KCTC 52523^T = JCM 31732^T) represents the type species of a novel genus of the family Flavobacteriaceae for which the name Thalassorhabdus aurantiaca gen. nov., sp. nov. is proposed.

Genome-Based Taxonomic Classification of Bacteroidetes

The bacterial phylum Bacteroidetes, characterized by a distinct gliding motility, occurs in a broad variety of ecosystems, habitats, life styles, and physiologies. Accordingly, taxonomic classification of the phylum, based on a limited number of features, proved difficult and controversial in the past, for example, when decisions were based on unresolved phylogenetic trees of the 16S rRNA gene sequence. Here we use a large collection of type-strain genomes from Bacteroidetes and closely related phyla for assessing their taxonomy based on the principles of phylogenetic classification and trees inferred from genome-scale data. No significant conflict between 16S rRNA gene and whole-genome phylogenetic analysis is found, whereas many but not all of the involved taxa are supported as monophyletic groups, particularly in the genome-scale trees. Phenotypic and phylogenomic features support the separation of Balneolaceae as new phylum Balneolaeota from Rhodothermaeota and of Saprospiraceae as new class Saprospiria from Chitinophagia. Epilithonimonas is nested within the older genus Chryseobacterium and without significant phenotypic differences; thus merging the two genera is proposed. Similarly, Vitellibacter is proposed to be included in Aequorivita. Flexibacter is confirmed as being heterogeneous and dissected, yielding six distinct genera. Hallella seregens is a later heterotypic synonym of Prevotella dentalis. Compared to values directly calculated from genome sequences, the G+C content mentioned in many species descriptions is too imprecise; moreover, corrected G+C content values have a significantly better fit to the phylogeny. Corresponding emendations of species descriptions are provided where necessary. Whereas most observed conflict with the current classification of Bacteroidetes is already visible in 16S rRNA gene trees, as expected whole-genome phylogenies are much better resolved.

Tamlana nanhaiensis sp. nov., isolated from surface seawater collected from the South China Sea

A polyphasic taxonomic study was performed on a strain, designated FHC16(T), which was isolated from surface seawater collected from the South China Sea. Cells of strain FHC16(T) are Gram stain-negative, oxidase- and catalase-positive and non-motile rods. Growth was observed at 15-37 °C (optimum, 25-30 °C), at pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 0-5 % (w/v) NaCl (optimum, 3%). 16S rRNA gene sequence analysis showed that strain FHC16(T) is most closely related to Tamlana sedimentorum JCM 19808(T) (98.2% sequence similarity). The ANI value between strain FHC16(T) and T. sedimentorum JCM 19808(T) was found to be 81.82-81.81%. The DNA-DNA hybridization estimated value between strain FHC16(T) and T. sedimentorum JCM 19808(T) was determined to be 25.8 ± 2.41%. The principal fatty acids (>5% of the total) were found to be iso-C(15:0), iso G-C(15:1), iso-C(17:0) 3-OH, iso-C(15:0) 3-OH and summed feature 3 (comprising C(16:1)ω7c/C(16:1)ω6c). The strain was found to have MK-6 as the major respiratory menaquinone, which is consistent with the other three recognized Tamlana species, T. sedimentorum, Tamlana crocina and Tamlana agarivorans. The polar lipids were found to comprise phosphatidylethanolamine, one unidentified aminophospholipid, two unidentified aminolipids and seven unidentified lipids. The G+C content of the chromosomal DNA was determined to be 34.2 mol%. On the basis of phenotypic, chemotaxonomic and molecular data, strain FHC16(T) is considered to represent a novel species of the genus Tamlana, for which the name Tamlana nanhaiensis sp. nov. is proposed. The type strain is FHC16(T) (.LMG 27420(T) = CGMCC 1.12469(T) = MCCC 1A06648(T)).