Genus Loktanella Research Articles

Thalassorhabdomicrobium marinisediminis gen. nov., sp. nov., a member of the family Hyphomonadaceae isolated from the Bohai Sea.

A novel Gram-stain-negative bacterium, designated strain BH-SD16T, was isolated from a marine sediment sample collected in the Bohai Sea. Cells of strain BH-SD16T are aerobic, non-flagellated oval-shaped rods, showing oxidase- and catalase-positive activities. Growth occurs between 15-45 °C (optimum, 30 °C), at pH 6.0-9.0 (pH 7.0-7.5) and with 1-10 % (w/v) NaCl (3.0 %). Strain BH-SD16T contains C18 : 1ω7c (49.2 %), C16 : 0 (17.7 %) and C18 : 1ω7c 11-methyl (16.6 %) as the predominant fatty acids and ubiquinone-10 as the major respiratory quinone. The major polar lipids comprise phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol and two glycolipids. The size of the draft genome is 3 442 538 bp, including 3213 protein-coding genes, 40 tRNA genes and three rRNA genes, and the DNA G+C content is 63.4 mol%. Strain BH-SD16T shows the highest 16S rRNA gene sequence similarity to Pseudooctadecabacter jejudonensis (95.7 %), strains of the genus Octadecabacter(95.4-95.6 %) and strains of the genus Loktanella(93.8-95.4 %). Phylogenetic trees based on 16S rRNA gene sequences show that strain BH-SD16T forms a distinct lineage within the family Hyphomonadaceae, which is also confirmed in the multigenic phylogenetic tree calculated by RAxML. Based on the results of phenotypic, chemotaxonomic and phylogenetic analysis, strain BH-SD16T is considered to represent a novel genus and species in the family Hyphomonadaceae, for which the name Thalassorhabdomicrobium marinisediminis gen. nov., sp. nov. is proposed. The type strain is BH-SD16T (=CCTCC AB 2017073T=KCTC 62201T).

Loktanella acticola sp. nov., isolated from seawater.

A Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated OISW-6T, was isolated from seawater near Oido, a South Korean island, and subjected to a polyphasic taxonomic study. Strain OISW-6T grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. The phylogenetic trees based on 16S rRNA gene sequences showed that strain OISW-6T fell within the clade comprising the type strains of Loktanella species. Strain OISW-6T exhibited 16S rRNA gene sequence similarity values of 97.0-98.9 % to Loktanellamaricola, Loktanellatamlensis, Loktanellarosea, Loktanellamaritima, Loktanellasediminilitoris and Loktanellalitorea, and of 94.0-96.3 % to the type strains of the other Loktanella species. Strain OISW-6T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids detected in strain OISW-6T were phosphatidylcholine, phosphatidylglycerol and one unidentified aminolipid. The DNA G+C content of strain OISW-6T was 57.3 mol% and its DNA-DNA relatedness values with the type strains of the six phylogenetically closely related Loktanella species were 8-25 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain OISW-6T is separated from recognized species of the genus Loktanella. On the basis of the data presented, strain OISW-6T is considered to represent a novel species of the genus Loktanella, for which the name Loktanellaacticola sp. nov. is proposed. The type strain is OISW-6T (=KCTC 52837T=NBRC 112781T).

Loktanella marina sp. nov., isolated from seawater.

A Gram-stain-negative, coccoid- or short-rod-shaped and non-motile bacterial strain, designated MDM-7T, was isolated from seawater of the Yellow Sea, South Korea, and was subjected to a polyphasic taxonomic study. Strain MDM-7T grew optimally at pH 7.0-8.0, at 30 °C and in the presence of 2-3 % (w/v) NaCl. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain MDM-7T fell within the clade comprising species of the genus Loktanella, clustering with the type strains of Loktanella vestfoldensisand Loktanella agnita, with which it exhibited 96.1 and 95.6 % similarity, respectively. 16S rRNA gene sequence similarity values between strain MDM-7T and the type strains of other Loktanella species were 93.1-95.0 %. The DNA G+C content of strain MDM-7T was 62.6 mol%. Strain MDM-7T contained Q-10 as the predominant ubiquinone and summed feature 8 (C18 : 1ω7c and/ or C18 : 1ω6c) as the major fatty acid. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and an unidentified aminolipid. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain MDM-7T is distinguishable from recognized Loktanella species. On the basis of the data presented, strain MDM-7T is considered to represent a novel species of the genus Loktanella, for which the name Loktanella marina sp. nov. is proposed. The type strain is MDM-7T (=KCTC 42722T=CECT 8899T).

Loktanella spp. Gb03 as an algicidal bacterium, isolated from the culture of Dinoflagellate Gambierdiscus belizeanus.

Aim:Bacteria associated with harmful algal blooms can play a crucial role in regulating algal blooms in the environment. This study aimed at isolating and identifying algicidal bacteria in Dinoflagellate culture and to determine the optimum growth requirement of the algicidal bacteria, Loktanella sp. Gb-03.Materials and Methods:The Dinoflagellate culture used in this study was supplied by Professor Gires Usup's Laboratory, School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, University Kebangsaan Malaysia, Malaysia. The culture was used for the isolation of Loktanella sp., using biochemical tests, API 20 ONE kits. The fatty acid content of the isolates and the algicidal activity were further evaluated, and the phenotype was determined through the phylogenetic tree.Results:Gram-negative, non-motile, non-spore-forming, short rod-shaped, aerobic bacteria (Gb01, Gb02, Gb03, Gb04, Gb05, and Gb06) were isolated from the Dinoflagellate culture. The colonies were pink in color, convex with a smooth surface and entire edge. The optimum growth temperature for the Loktanella sp. Gb03 isolate was determined to be 30°C, in 1% of NaCl and pH7. Phylogenetic analysis based on 16S rRNA gene sequences showed that the bacterium belonged to the genus Loktanella of the class Alphaproteobacteria and formed a tight cluster with the type strain of Loktanella pyoseonensis (97.0% sequence similarity).Conclusion:On the basis of phenotypic, phylogenetic data and genetic distinctiveness, strain Gb-03, were placed in the genus Loktanella as the type strain of species. Moreover, it has algicidal activity against seven toxic Dinoflagellate. The algicidal property of the isolated Loktanella is vital, especially where biological control is needed to mitigate algal bloom or targeted Dinoflagellates.

Loktanella aquimaris sp. nov., Isolated from Seawater.

Two novel bacterial strains, designated C5(T) and C9 were isolated from a fish cage at Tongyeong, South Korea and were characterized to determine their taxonomic position. The strains were Gram-negative, non-motile, strictly aerobic and short rod shaped. Growth occurred between 20 and 32°C (optimum 30°C) and at pH 6.0-9.0 (optimum pH 8.0) and at 0-10% NaCl (optimum at 2% NaCl). Based on the 16S rRNA gene sequence analysis, they were identified as a member of the genus Loktanella that belongs to the phylum Proteobacteria. Strains C5(T) and C9 were analyzed by a polyphasic approach, revealing variations in their phenotypic characters but reciprocal DNA-DNA hybridization values confirmed that they belong to the same species. Phylogenetic analysis of the 16S rRNA gene sequences of closely related species indicated their similarities were below 97%. The predominant isoprenoid quinone is ubiquinone-10 (Q-10). The major cellular fatty acids were C16:0, and C18:1 ω7c. Major polar lipid contained phosphatidylglycerol (PG), phosphatidycholine (PC), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), unidentified amino lipid (AL) and unidentified lipids (L1-3). Based on phylogenetic and phenotypic data, the isolated strains represent a novel species of the genus Loktanella, for which the name Loktanella aquimaris sp. nov. is proposed. The type strains were C5(T) (=KEMB 3-892(T)=JCM 30382(T)), and a second strain is C9 (=KEMB 3-893=JCM 30383).

Loktanella sediminum sp. nov., isolated from marine surface sediment.

A Gram-staining-negative, strictly aerobic and short rod-shaped bacterium, designated strain S3B03(T), was isolated from the sediment of the northern Okinawa Trough. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S3B03(T) belonged to the genus Loktanella (family Rhodobacteraceae) and showed the highest sequence similarity with Loktanella litorea KCTC 23883(T) (96.16 %) and 92.99-95.90 % 16S rRNA gene sequence similarity to other members of the genus Loktanella. Optimal growth occurred in the presence of 2-5 % (w/v) NaCl at pH 7.0-8.0 and 28-32 °C. Ubiquinone-10 (Q-10) was the predominant respiratory quinone. The major fatty acids (>10 % of the total fatty acids) were C18 : 1ω7c and/or C18 : 1ω6c. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and two unidentified polar lipids. The DNA G+C content of strain S3B03(T) was 57.6 mol%. On the basis of polyphasic analysis, strain S3B03(T) is considered to represent a novel species of the genus Loktanella, for which the name Loktanella sediminum sp. nov. is proposed. The type strain is S3B03(T) ( = JCM 30120(T) = DSM 28715(T) = MCCC 1K00257(T)).

Loktanella aestuariicola sp. nov., an alphaproteobacterium isolated from a tidal flat.

A Gram-stain negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, J-TF4(T), which was isolated from a tidal flat in the South Sea of South Korea, was characterized taxonomically. Strain J-TF4(T) was found to grow optimally at 30 °C, at pH 7.0-8.0 and in presence of 2.0-3.0% (w/v) NaCl. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain J-TF4(T) fell within the clade comprising the type strains of Loktanella species, clustering with the type strains of Loktanella cinnabarina, Loktanella hongkongensis, Loktanella soesokkakensis, Loktanella pyoseonensis and 'Loktanella variabilis' showing sequence similarity values of 97.2-98.4%. The strain exhibited 16S rRNA gene sequence similarity values of 94.1-95.4% to the type strains of the other Loktanella species. Strain J-TF4(T) was found to have Q-10 as the predominant ubiquinone and C(18:1) ω7c as the major fatty acid. The major polar lipids of strain J-TF4(T) were identified as phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid and an unidentified aminolipid. The DNA G+C content of strain J-TF4(T) was determined to be 67.9 mol% and its mean DNA-DNA relatedness values with the type strains of five phylogenetically related Loktanella species were 17.7-23.3%. Differential phenotypic properties, together with the phylogenetic and genetic data, demonstrate that strain J-TF4(T) is separated from other Loktanella species. On the basis of the data presented, strain J-TF4(T) is considered to represent a novel species of the genus Loktanella, for which the name Loktanella aestuariicola sp. nov. is proposed. The type strain is J-TF4(T) (=KCTC 42135(T)=NBRC 110408(T)).

Loktanella soesokkakensis sp. nov., isolated from the junction between the North Pacific Ocean and a freshwater spring

A Gram-negative, aerobic, non-flagellated and rod-shaped or ovoid bacterial strain, designated DSSK1-5(T), was isolated from the junction between the North Pacific Ocean and a freshwater spring at Jeju island, South Korea. Strain DSSK1-5(T) was found to grow optimally at 30°C, at pH 7.0-8.0 and in the presence of 2.0-3.0% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain DSSK1-5(T) fell within the clade comprising Loktanella species, clustering consistently with the type strains of Loktanella hongkongensis and Loktanella cinnabarina, with which it exhibited 98.9 and 98.4% sequence similarity values, respectively. Sequence similarities to the type strains of the other recognized Loktanella species were 94.0-96.2%. Strain DSSK1-5(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the major fatty acid. The major polar lipids of strain DSSK1-5(T) were identified as phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified glycolipid and one unidentified aminolipid. The DNA G+C content of strain DSSK1-5(T) was determined to be 67.6mol% and its mean DNA-DNA relatedness values with L. hongkongensis JCM 12479(T) and L. cinnabarina JCM 18161(T) were 19 and 23%, respectively. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain DSSK1-5(T) is separated from other Loktanella species. On the basis of the data presented, strain DSSK1-5(T) is proposed to represent a novel species of the genus Loktanella, for which the name Loktanella soesokkakensis sp. nov. is proposed. The type strain is DSSK1-5(T) (=KCTC 32425(T)=CECT 8367(T)).

Loktanella tamlensis sp. nov., isolated from seawater

An aerobic, Gram-reaction-negative, chemo-organotrophic bacterium, designated strain SSW-35(T), was isolated from seawater in Jeju, Republic of Korea. Cells were motile, short rods; colonies were circular, smooth, convex, translucent and beige in colour. No diffusible pigment formed on any of the media tested. The bacterium grew at 4-30 °C and pH 7.1-10.1. Phylogenetic analysis based on 16S rRNA gene sequences showed that the organism was related to members of the genus Loktanella, its closest recognized relatives being Loktanella rosea Fg36(T) (98.1% sequence similarity) and Loktanella maricola DSW-18(T) (97.8%). Levels of 16S rRNA gene similarity between strain SSW-35(T) and other recognized species of the genus Loktanella were all <97%. Polar lipid analysis revealed the presence of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unknown lipid as major components, as well as small amounts of two unknown phospholipids. The predominant ubiquinone was Q-10. The major cellular fatty acid was C(18:1) (summed feature 7), and the 3-hydroxy fatty acids detected were C(12:1) 3-OH and C(10:0) 3-OH. The genomic DNA G+C content was 55.0 mol%. In DNA-DNA hybridization experiments, the relatedness values between strain SSW-35(T) and the type strains of the phylogenetically closest recognized species were all <11%. On the basis of the phenotypic and genotypic characteristics, phylogenetic analysis and DNA-DNA relatedness, a novel species, Loktanella tamlensis sp. nov., is proposed. The type strain is SSW-35(T) (=KCTC 12722(T)=JCM 14020(T)).

Loktanella pyoseonensis sp. nov., isolated from beach sand, and emended description of the genus Loktanella

A novel Gram-stain-negative, aerobic, heterotrophic, obligately halophilic bacterium, designated strain JJM85(T), was isolated from beach sand in Jeju, Republic of Korea. Cells were rod-shaped and motile by means of flagella; colonies were pink, convex and smooth with an entire edge. The organism grew at pH 5.0-10.0 and 4-30 degrees C. Phylogenetic analysis based on 16S rRNA gene sequences showed that the organism belonged to the genus Loktanella of the class Alphaproteobacteria and formed a tight cluster with the type strain of Loktanella hongkongensis (96.0 % sequence similarity). The DNA G+C content and fatty acid profile of the novel strain supported affiliation with the genus Loktanella. However, the novel strain could be differentiated clearly from members of this genus by cell motility, some physiological properties and low 16S rRNA gene sequence similarity (93.1-96.0 %). On the basis of the polyphasic data presented here, strain JJM85(T) is considered to represent a novel species of the genus Loktanella, for which the name Loktanella pyoseonensis sp. nov. is proposed; the type strain is JJM85(T) (=KCTC 22372(T) =DSM 21424(T)).

Loktanella atrilutea sp. nov., isolated from seawater in Japan

A Gram-negative, rod-shaped bacterium, IG8(T), was isolated from seawater off the Sanriku coast, Japan. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain IG8(T) represented a separate lineage within the genus Loktanella; the highest 16S rRNA gene sequence similarity values were found with the type strains of Loktanella salsilacus (98.6 %) and Loktanella fryxellensis (98.4 %). DNA-DNA hybridization values between strain IG8(T) and the type strains of L. salsilacus (27.9-36.1 %) and L. fryxellensis (11.3-31.0 %) were clearly below 70 %, the generally accepted limit for species delineation. The DNA G+C content of strain IG8(T) was 66.3 mol%. On the basis of DNA-DNA hybridization, some biochemical characteristics and 16S rRNA gene sequence comparison, it is proposed that the isolate represents a novel species, Loktanella atrilutea sp. nov. The type strain is IG8(T) (=IAM 15450(T)=NCIMB 14280(T)).

Loktanella maricola sp. nov., isolated from seawater of the East Sea in Korea

A Gram-negative, non-motile and rod-shaped Loktanella-like bacterial strain, DSW-18(T), was isolated from seawater of the East Sea, Korea, and its exact taxonomic position was investigated by using a polyphasic approach. Strain DSW-18(T) grew optimally at pH 7.0-8.0 and 25 degrees C in the presence of 2 % (w/v) NaCl. It contained Q-10 as the predominant ubiquinone and C(18 : 1) omega 7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content was 56.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DSW-18(T) fell within the cluster comprising Loktanella species. The levels of 16S rRNA gene sequence similarity between strain DSW-18(T) and the type strains of recognized Loktanella species ranged from 94.4 to 98.4 %. The DNA-DNA relatedness data and differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain DSW-18(T) was distinguishable from recognized Loktanella species. On the basis of the phenotypic, phylogenetic and genetic data, strain DSW-18(T) represents a novel species of the genus Loktanella, for which the name Loktanella maricola sp. nov. is proposed. The type strain is DSW-18(T) (=KCTC 12863(T)=JCM 14564(T)).

Loktanella koreensis sp. nov., isolated from sea sand in Korea

A bacterial strain, GA2-M3(T), isolated from a sea-sand sample in Korea, was subjected to polyphasic taxonomic characterization. Cells of strain GA2-M3(T) were Gram-negative, non-motile, non-spore-forming and short rod- to ovoid-shaped. Comparative 16S rRNA gene sequencing studies confirmed that the bacterium fell within the radiation of the genus Loktanella. Similarity levels between the 16S rRNA gene sequence of strain GA2-M3(T) and those of type strains of Loktanella species with validly published names were 93.5-96.1 %; highest sequence similarity was with Loktanella rosea. The G+C content of the genomic DNA of strain GA2-M3(T) was 60.0 mol% and the predominant ubiquinone was Q-10. Major fatty acids were 18 : 1omega7c, 18 : 0 and 18 : 1omega7c 11-methyl. On the basis of the evidence presented, it is proposed that strain GA2-M3(T) represents a novel species, for which the name Loktanella koreensis sp. nov. is proposed. The type strain is GA2-M3(T) (=KACC 11519(T)=DSM 17925(T)).

Loktanella agnita sp. nov. and Loktanella rosea sp. nov., from the north-west Pacific Ocean

One whitish and four pinkish strains of Gram-negative, non-motile, aerobic bacteria were isolated from sea-water and sediment samples collected in Chazhma Bay (Sea of Japan, Pacific Ocean). Analysis of 16S rRNA gene sequences revealed that these strains belonged to the 'Alphaproteobacteria', having highest sequence similarity of about 94-97% with species of the genus Loktanella. None of the strains degraded gelatin, casein, chitin, agar, DNA or starch and they had limited ability to utilize carbon sources. The four pinkish strains, Fg36(T), Fg1, Fg116 and Fg117, degraded Tween 80. Sea-water strain R10SW5(T) grew at 3-6% NaCl and a temperature range of 8-35 degrees C, whilst strains Fg36(T), Fg1, Fg116 and Fg117 grew at NaCl concentrations of 1-12% and a temperature range of 4-35 degrees C. Phosphatidylglycerol (58/79%), diphosphatidylglycerol (11/6%) and phosphatidylcholine (28/22%) were the major phospholipids. The predominant fatty acids were 16:0 (12.2/8.6%) and 18:1omega7 (76.6/68.4%). The DNA G+C content of strain R10SW5(T) was 59.1 mol% and those of the four pinkish strains ranged from 60.5 to 61.8 mol%. Based on the results of phenotypic, genotypic, chemotaxonomic and phylogenetic investigation, two novel species, Loktanella agnita sp. nov. and Loktanella rosea sp. nov., are proposed. The type strains are R10SW5(T) (=KMM 3788(T)=CIP 107883(T)) and Fg36(T) (=KMM 6003(T)=CIP 107851(T)=LMG 22534(T)), respectively.

Loktanella hongkongensis sp. nov., a novel member of the α-Proteobacteria originating from marine biofilms in Hong Kong waters

A Gram-negative, non-motile, non-spore-forming, short rod-shaped bacterium (UST950701-009P(T)) was isolated from a marine biofilm in Hong Kong waters. Colonies are pink in colour, convex with a smooth surface and entire edge. Brown diffusible pigment is produced. Whitish colonies, with otherwise identical morphology, emerge from every culture upon ageing. The white colonies can be maintained as separate cultures (UST950701-009W) without turning pink. UST950701-009P(T) and UST950701-009W have identical 16S rRNA gene sequences and similar G+C (65.9-66.2 mol%) and fatty acid (86.22-88.52 % 18 : 1omega7c) contents. Phylogenetic analysis of the 16S rRNA gene sequence places UST950701-009P(T) within the Rhodobacter group of the alpha-subclass of the Proteobacteria. The nearest neighbours belong to the genus Loktanella, with similarity values ranging from 94.5 to 95.5 %. Data on G+C and fatty acid contents support the affiliation to the genus Loktanella. UST950701-009P(T) and -009W are heterotrophic, strictly aerobic and require NaCl for growth (2.0-14.0 %). Both grow in pH 5.0-10.0 and at 8-44 degrees C. Both are positive in oxidase, catalase and beta-galactosidase tests, but they differ in the pattern of carbohydrate oxidation and assimilation. Molecular evidence together with phenotypic characteristics shows that UST950701-009P(T) constitutes a novel species within the genus Loktanella. The name Loktanella hongkongensis sp. nov. is proposed; the type strain is UST950701-009P(T) (=NRRL B-41039(T)=JCM 12479(T)) and a morphovar is UST950701-009W (=NRRL B-41040=JCM 12480).