First report of Perkinsus olseni infections in blood cockles Tegillarca granosa on the south coast of Korea.

The protozoan parasite Perkinsus olseni has become a focus of attention since it has been responsible for mass mortalities and economic losses in a wide range of bivalve hosts globally. The P. olseni host range along the south coast of Korea may extend beyond what was previously understood, and blood cockles in the Family Arcidae are also suggested to be potential hosts of P. olseni. In the present study, we applied histology and molecular techniques to identify Perkinsus sp. infections in the blood cockles Tegillarca granosa, which have been commercially exploited on the south coast of Korea for several decades. Histology and molecular techniques, including genus-specific immunofluorescence assay, species-specific fluorescence in situ hybridization, and phylogeny based on the ribosomal DNA internal transcribed spacer region revealed that T. granosa is infected by P. olseni, although the prevalence was low (0.5%). Histology revealed massive hemocyte infiltrations in the mantle, gill, and digestive gland connective tissues, indicating that the infection exerts negative impacts on the host cockles.

Diagnostic validity of molecular diagnostic assays for white spot syndrome virus at different severity grades.

The high virulence of the white spot syndrome virus (WSSV) in acute infections and the lack of effective treatments underscore the necessity for a rapid, accurate, and efficient diagnostic process to control white spot disease. The analytical sensitivity of diagnostic assays (polymerase chain reactions; PCRs and rapid diagnostic kit) at different severity grades of WSSV infection were determined using the 95% limit of detection (LOD95%). The LOD95% of nested, real-time, and one-step PCRs and rapid diagnostic kit were 0.70, 4.67, 1.19, and 79,434.65 viral genome copies/reactions, respectively. From the intramuscular challenge tests conducted under different dose and temperature conditions, the WSSV severity grades of time-course collected whiteleg shrimp (Litopenaeus vannamei) and dead or live shrimps were determined based on the viral loads of the pleopod. By applying the WSSV severity grades, a total of 92 shrimps were classified as G0. Furthermore, 92, 66, 199, and 79 shrimps were classified as G1, G2, G3, and G4, respectively. Additionally, 222 shrimps were classified as negative as WSSV was not confirmed in the nested PCR assay. Diagnostic sensitivity (DSe) and specificity (DSp) values of molecular diagnostic assays were compared with those of nested PCR in artificial WSSV-infected shrimp to evaluate diagnostic performance. The real-time and one-step PCRs exhibited a DSe >92.4% for G0 grade (approximately 101-102 copies/mg), indicating WSSV detection at low copy numbers. The rapid diagnostic kit presented a DSe >92.4% for G2 grade (approximately 104-105 copies/mg), suggesting the detection of WSSV-infected shrimp with clinical signs during the endemic period. These results suggest that the strategy of presumptive diagnosis using one-step PCR and rapid diagnostic kit at different seasonal periods followed by confirmatory diagnosis using real-time PCR assay could aid in controlling WSD with rapidity, accuracy, and cost-effectiveness.

Roseovarius pelagicus sp. nov., a facultatively anaerobic bacterium with potential for degrading polypropylene, isolated from Arctic seawater.

A Gram-stain-negative, facultatively anaerobic, non-motile, rod-shaped bacterial strain, designated HL-MP18T, was isolated from Arctic seawater after a prolonged incubation employing polypropylene as the sole carbon source. Phylogenetic analyses of the 16S rRNA gene sequence revealed that strain HL-MP18T was affiliated to the genus Roseovarius with close relatives Roseovarius carneus LXJ103T (96.8 %) and Roseovarius litorisediminis KCTC 32327T (96.5 %). The complete genome sequence of strain HL-MP18T comprised a circular chromosome of 3.86 Mbp and two circular plasmids of 0.17 and 0.24 Mbp. Genomic comparisons based on average nucleotide identity and digital DNA-DNA hybridization showed that strain HL-MP18T was consistently discriminated from its closely related taxa in the genus Roseovarius. Strain HL-MP18T showed optimal growth at 25 °C, pH 7.0 and 2.5 % (w/v) sea salts. The major cellular fatty acids were C18 : 1 ω6c and/or C18 : 1 ω7c (49.6 %), C19 : 0 cyclo ω8c (13.5 %), and C16 : 0 (12.8 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and three unidentified lipids. The genomic DNA G+C content of the strain was 59.2 mol%. The phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strain HL-MP18T is distinguishable from the recognized species of the genus Roseovarius. Therefore, we propose that strain HL-MP18T represents a novel species belonging to the genus Roseovarius, for which the name Roseovarius pelagicus sp. nov. is proposed. The type strain is HL-MP18T (=KCCM 90405T=JCM 35639T).

Identification of Structural and Morphogenesis Genes of Sulfitobacter Phage ΦGT1 and Placement within the Evolutionary History of the Podoviruses.

ΦGT1 is a lytic podovirus of an alphaproteobacterial Sulfitobacter species, with few closely matching sequences among characterized phages, thus defying a useful description by simple sequence clustering methods. The history of the ΦGT1 core structure module was reconstructed using timetrees, including numerous related prospective prophages, to flesh out the evolutionary lineages spanning from the origin of the ejectosomal podovirus >3.2 Gya to the present genes of ΦGT1 and its closest relatives. A peculiarity of the ΦGT1 structural proteome is that it contains two paralogous tubular tail A (tubeA) proteins. The origin of the dual tubeA arrangement was traced to a recombination between two more ancient podoviral lineages occurring ~0.7 Gya in the alphaproteobacterial order Rhizobiales. Descendants of the ancestral dual A recombinant were tracked forward forming both temperate and lytic phage clusters and exhibiting both vertical transmission with patchy persistence and horizontal transfer with respect to host taxonomy. The two ancestral lineages were traced backward, making junctions with a major metagenomic podoviral family, the LUZ24-like gammaproteobacterial phages, and Myxococcal phage Mx8, and finally joining near the origin of podoviruses with P22. With these most conservative among phage genes, deviations from uncomplicated vertical and nonrecombinant descent are numerous but countable. The use of timetrees allowed conceptualization of the phage's evolution in the context of a sequence of ancestors spanning the time of life on Earth.

Evaluation of the Horizontal Transmission of White Spot Syndrome Virus for Whiteleg Shrimp (Litopenaeus vannamei) Based on the Disease Severity Grade and Viral Shedding Rate.

White spot syndrome virus (WSSV) is the most problematic pathogen in crustaceans. In this study, we investigated the horizontal transmission model of WSSV based on the correlation between the disease severity grade and viral shedding rate and determined the minimum infective dose of WSSV via the waterborne route. Intramuscular injection challenges at different doses and water temperatures revealed that the thresholds of viral shedding and mortality were G1 (3.1 × 103 copies/mg) and G2 (8.5 × 104 copies/mg), respectively. Furthermore, a positive linear correlation was observed between viral copies of pleopods and viral shedding rate (y = 0.7076x + 1.414; p < 0.001). Minimum infective doses of WSSV were determined via an immersion challenge. Infection was observed within 1, 3, and 7 d in 105-, 103-, and 101 copies/mL of seawater, respectively. In the cohabitation challenge, infection was observed within six days with viral loads of 101 to 102 copies/mL of seawater, which further increased in the recipient group. Our results indicate a positive correlation between disease severity grade and viral shedding rate of infected shrimp and suggest that the waterborne transmission of WSSV depends on the viral load and exposure period.

First Report of Enterocytozoon hepatopenaei Infection in Giant Freshwater Prawn (Macrobrachium rosenbergii de Man) Cultured in the Republic of Korea.

In the Republic of Korea, Enterocytozoon hepatopenaei (EHP) was first isolated from Pacific whiteleg shrimp in April 2020; however, there are no existing reports of EHP infection in other shrimp or prawns. Here, we aimed to investigate EHP infection and its prevalence in giant freshwater prawn farms in the Republic of Korea. We tested prawns from 22 farms for EHP infection, and samples from eight farms showed positive EHP infection results in 2021. In EHP-infected prawn farms, the prevalence ranged from 4.9% to 18.2%. The prevalence of EHP infection in the Republic of Korea, derived from the prevalence in prawn farms, was estimated to be 0.8% in 2021. The proliferation of EHP was observed within the hepatopancreatic epithelial cells of prawns using H&E and Giemsa staining. Mature EHP was observed in the sinus between epithelial cells of the digestive tubules. Phylogenetic analysis revealed a clade distinct from the previously reported EHP in Pacific whiteleg shrimps. This is the first report of EHP infection in a giant freshwater prawn in the Republic of Korea, where the prevalence of EHP infection is not high, but it is recognized as an emerging disease that requires periodic monitoring and quarantine management in giant freshwater prawns.

First Report of Enterocytozoon hepatopenaei Infection in Pacific Whiteleg Shrimp (Litopenaeus vannamei) Cultured in Korea.

The consumption of cultured crustaceans has been steadily increasing, and Pacific whiteleg shrimp (Litopenaeus vannamei) are major cultivated invertebrates worldwide. However, shrimp productivity faces a variety of challenges, mainly related to outbreaks of lethal or growth retardation-related diseases. In particular, hepatopancreatic microsporidiosis caused by the microsporidian parasite Enterocytozoon hepatopenaei (EHP) is an important disease associated with growth retardation in shrimp. Here, we report the detection of EHP through histopathological, molecular and electron microscopy methods in the hepatopancreas of Pacific whiteleg shrimp with growth disorder in a South Korean farm. Phylogenetic analysis showed a clade distinct from the previously reported EHP strains isolated in Thailand, India, China and Vietnam. An EHP infection was not associated with inflammatory responses such as hemocyte infiltration. Although EHP infection has been reported worldwide, this is the first report in the shrimp aquaculture in Korea. Therefore, an EHP infection should be managed and monitored regularly for effective disease control and prevention.

Sandaracinobacter neustonicus sp. nov., isolated from the sea surface microlayer in the Southwestern Pacific Ocean, and emended description of the genus Sandaracinobacter.

A Gram-stain-negative, non-motile, facultatively anaerobic and rod-shaped bacterial strain, designated PAMC 28131T, was isolated from a sea surface microlayer sample in the open water of the Pacific Ocean. Phylogenetic analysis of the 16S rRNA gene sequence of strain PAMC 28131T revealed an affiliation to the genus Sandaracinobacter with the closest species Sandaracinobacter sibiricus RB16-17T (sequence similarity of 98.2 %). Strain PAMC 28131T was able to grow optimally with 0.5-1.0 % NaCl and at pH 6.5-7.0 and 30 °C. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, an unidentified aminolipid, an unidentified glycolipid and an unidentified lipid. The major cellular fatty acids (>10 %) were C18 : 1 ω6c and/or C18 : 1 ω7c, (42.6 %), C17 : 1 ω6c (19.3 %) and C16 : 1 ω6c and/or C16 : 1 ω7c (15.8 %), and the respiratory quinone was Q-10. The genomic DNA G+C content was 65.3 mol%. The phylogenetic, phenotypic and chemotaxonomic data showed that strain PAMC 28131T could be clearly distinguished from S. sibiricus RB16-17T. Thus, strain PAMC 28131T should be classified as representing a novel species in the genus Sandaracinobacter, for which the name Sandaracinobacter neustonicus sp. nov. is proposed. The type strain is PAMC 28131T (=KCCM 43127T=JCM 30734T).

Pseudomonas neustonica sp. nov., isolated from the sea surface microlayer of the Ross Sea (Antarctica).

Gram-stain-negative, aerobic and rod-shaped bacterial strains, designated SSM26T and SSM44, were isolated from a sea surface microlayer sample from the Ross Sea, Antarctica. Analysis of the 16S rRNA gene sequences of strains SSM26T and SSM44 revealed a clear affiliation with the genus Pseudomonas. Based on the results of phylogenetic analysis, strains SSM26T and SSM44 showed the closest phylogenetic relationship with the species Pseudomonas sabulinigri KCTC 22137T with the 16S rRNA gene sequence similarity level of 98.5 %. Strains SSM26T and SSM44 grew optimally at 30 °C, pH 7.0-7.5 and 0.5-10.0 % NaCl (w/v). The major cellular fatty acids were C18 : 1 ω7c (31.3-34.9 %), C16 : 0 (15.5-20.2 %), summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c; 19.5-25.4 %) and C12 : 0 (6.0-9.3 %). The genomic DNA G+C content of each strain was 56.2 mol%. Genomic relatedness analyses based on the average nucleotide identity and the genome-to-genome distance showed that strains SSM26T and SSM44 constituted a single species that was clearly distinguishable from its phylogenetically close relatives. The combined phenotypic, chemotaxonomic, genomic and phylogenetic data also showed that strains SSM26T and SSM44 could be distinguished from validly published members of the genus Pseudomonas. Thus, these strains should be classified as representing a novel species in the genus Pseudomonas, for which the name Pseudomonas neustonica sp. nov. is proposed with the type strain SSM26T (=KCCM 43193T=JCM 31284T=PAMC 28426T) and a sister strain SSM44 (=KCCM 43194=JCM 31285=PAMC 28427).

Arctic Primary Aerosol Production Strongly Influenced by Riverine Organic Matter.

The sources of primary and secondary aerosols in the Arctic are still poorly known. A number of surface seawater samples-with varying degrees of Arctic riverine and sea ice influences-were used in a sea spray generation chamber to test them for their potential to produce sea spray aerosols (SSA) and cloud condensation nuclei (CCN). Our interdisciplinary data showed that both sea salt and organic matter (OM) significantly influenced the SSA production. The number concentration of SSA in the coastal samples was negatively correlated with salinity and positively correlated with a number of OM tracers, including dissolved and chromophoric organic carbon (DOC, CDOM), marine microgels and chlorophyll a (Chl-a) but not for viral and bacterial abundances; indicating that OM of riverine origin enhances primary aerosol production. When all samples were considered, transparent exopolymer particles (TEP) were found to be the best indicator correlating positively with the ratio number concentration of SSA/salinity. CCN efficiency was not observed to differ between the SSA from the various samples, despite differences in organic characteristics. It is suggested that the large amount of freshwater from river runoff have a substantial impact on primary aerosols production mechanisms, possibly affecting the cloud radiative forcing.

Shewanella psychromarinicola sp. nov., a psychrophilic bacterium isolated from pelagic sediment of the Ross Sea (Antarctica), and reclassification of Shewanella arctica Kim et al. 2012 as a later heterotypic synonym of Shewanella frigidimarina Bowman et al. 1997.

Two Gram-stain-negative, rod-shaped, facultatively anaerobic, iron-reducing bacterial strains, designated M2T and R106, were isolated from pelagic surface-sediment of the Ross Sea, Antarctica. The 16S rRNA gene sequence analysis revealed that strains M2T and R106 were affiliated to the genus Shewanellaand formed a distinct subline in a robust clade encompassing Shewanella vesiculosa, Shewanella livingstonensis, Shewanella arcticaand Shewanella frigidimarinawith a range of sequence similarities of 98.1-98.9 %. Overall genome relatedness indices indicated that M2T and R106 represented a single genomic species, which was clearly distinguishable from the phylogenetically close relatives with lower values of species delineation thresholds. Cells of M2T grew optimally at 10-15 °C and pH 6.5 in the presence of 3.0-4.0 % (w/v) sea salts. The polar lipids of M2T comprised phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified aminolipid and an unidentified phospholipid. Quinones were Q-7, Q-8, MK-7 and MMK-7. The major cellular fatty acids (>10 %) were C16 : 1ω7c and/or C16 : 1ω6c, C16 : 0 and C17 : 1ω8c. The DNA G+C content was 42.2 mol%. On the basis of the phenotypic, phylogenetic, genomic and chemotaxonomic features, we propose the name Shewanellapsychromarinicola sp. nov. with the type strain M2T (=KCCM 43257T =JCM 32090T) and the reclassification of S. arcticaas a later heterotypic synonym of S. frigidimarina.

Complete genome of streamlined marine actinobacterium Pontimonas salivibrio strain CL-TW6T adapted to coastal planktonic lifestyle.

BACKGROUND: Pontimonas salivibrio strain CL-TW6T (=KCCM 90105 = JCM18206) was characterized as the type strain of a new genus within the Actinobacterial family Microbacteriaceae. It was isolated from a coastal marine environment in which members of Microbactericeae have not been previously characterized. RESULTS: The genome of P. salivibrio CL-TW6T was a single chromosome of 1,760,810 bp. Genomes of this small size are typically found in bacteria growing slowly in oligotrophic zones and said to be streamlined. Phylogenetic analysis showed it to represent a lineage originating in the Microbacteriaceae radiation occurring before the snowball Earth glaciations, and to have a closer relationship with some streamlined bacteria known through metagenomic data. Several genomic characteristics typical of streamlined bacteria are found: %G + C is lower than non-streamlined members of the phylum; there are a minimal number of rRNA and tRNA genes, fewer paralogs in most gene families, and only two sigma factors; there is a noticeable absence of some nonessential metabolic pathways, including polyketide synthesis and catabolism of some amino acids. There was no indication of any phage genes or plasmids, however, a system of active insertion elements was present. P. salivibrio appears to be unusual in having polyrhamnose-based cell wall oligosaccharides instead of mycolic acid or teichoic acid-based oligosaccharides. Oddly, it conducts sulfate assimilation apparently for sulfating cell wall components, but not for synthesizing amino acids. One gene family it has more of, rather than fewer of, are toxin/antitoxin systems, which are thought to down-regulate growth during nutrient deprivation or other stressful conditions. CONCLUSIONS: Because of the relatively small number of paralogs and its relationship to the heavily characterized Mycobacterium tuberculosis, we were able to heavily annotate the genome of P. salivibrio CL-TW6T. Its streamlined status and relationship to streamlined metagenomic constructs makes it an important reference genome for study of the streamlining concept. The final evolutionary trajectory of CL-TW6 T was to adapt to growth in a non-oligotrophic coastal zone. To understand that adaptive process, we give a thorough accounting of gene content, contrasting with both oligotrophic streamlined bacteria and large genome bacteria, and distinguishing between genes derived by vertical and horizontal descent.

Computationally Efficient Automatic Coast Mode Target Tracking Based on Occlusion Awareness in Infrared Images.

This paper proposes the automatic coast mode tracking of centroid trackers for infrared images to overcome the target occlusion status. The centroid tracking method, using only the brightness information of an image, is still widely used in infrared imaging tracking systems because it is difficult to extract meaningful features from infrared images. However, centroid trackers are likely to lose the track because they are highly vulnerable to screened status by the clutter or background. Coast mode, one of the tracking modes, maintains the servo slew rate with the tracking rate right before the loss of track. The proposed automatic coast mode tracking method makes decisions regarding entering coast mode by the prediction of target occlusion and tries to re-lock the target and resume the tracking after blind time. This algorithm comprises three steps. The first step is the prediction process of the occlusion by checking both matters which have target-likelihood brightness and which may screen the target despite different brightness. The second step is the process making inertial tracking commands to the servo. The last step is the process of re-locking a target based on the target modeling of histogram ratio. The effectiveness of the proposed algorithm is addressed by presenting experimental results based on computer simulation with various test imagery sequences compared to published tracking algorithms. The proposed algorithm is tested under a real environment with a naval electro-optical tracking system (EOTS) and airborne EO/IR system.

Prokaryotic community composition in alkaline-fermented skate (Raja pulchra).

Prokaryotes were extracted from skates and fermented skates purchased from fish markets and a local manufacturer in South Korea. The prokaryotic community composition of skates and fermented skates was investigated using 16S rRNA pyrosequencing. The ranges for pH and salinity of the grinded tissue extract from fermented skates were 8.4-8.9 and 1.6-6.6%, respectively. Urea and ammonia concentrations were markedly low and high, respectively, in fermented skates compared to skates. Species richness was increased in fermented skates compared to skates. Dominant and predominant bacterial groups present in the fermented skates belonged to the phylum Firmicutes, whereas those in skates belonged to Gammaproteobacteria. The major taxa found in Firmicutes were Atopostipes (Carnobacteriaceae, Lactobacillales) and/or Tissierella (Tissierellaceae, Tissierellales). A combination of RT-PCR and pyrosequencing for active bacterial composition showed that the dominant taxa i.e., Atopostipes and Tissierella, were active in fermented skate. Those dominant taxa are possibly marine lactic acid bacteria. Marine bacteria of the taxa Lactobacillales and/or Clostridia seem to be important in alkaline fermentation of skates.

High-quality draft genome sequence of Gracilimonas tropica CL-CB462(T) (DSM 19535(T)), isolated from a Synechococcus culture.

Gracilimonas tropica Choi et al. 2009 is a member of order Sphingobacteriales, class Sphingobacteriia. Three species of the genus Gracilimonas have been isolated from marine seawater or a salt mine and showed extremely halotolerant and mesophilic features, although close relatives are extremely halophilic or thermophilic. The type strain of the type species of Gracilimonas, G. tropica DSM19535(T), was isolated from a Synechococcus culture which was established from the tropical sea-surface water of the Pacific Ocean. The genome of the strain DSM19535(T) was sequenced through the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes project. Here, we describe the genomic features of the strain. The 3,831,242 bp long draft genome consists of 48 contigs with 3373 protein-coding and 53 RNA genes. The strain seems to adapt to phosphate limitation and requires amino acids from external environment. In addition, genomic analyses and pasteurization experiment suggested that G. tropica DSM19535(T) did not form spore.

Gracilimonas rosea sp. nov., isolated from tropical seawater, and emended description of the genus Gracilimonas.

A Gram-staining-negative, non-motile, spore-forming, rod-shaped, marine bacterial strain, CL-KR2(T), was isolated from tropical seawater near Kosrae, an island in the Federated States of Micronesia. Analysis of the 16S rRNA gene sequence of strain CL-KR2(T) revealed a clear affiliation with the genus Gracilimonas. Based on phylogenetic analysis, strain CL-KR2(T) showed the closest phylogenetic relationship to Gracilimonas tropica CL-CB462(T), with 16S rRNA gene sequence similarity of 96.6 %. DNA-DNA relatedness between strain CL-KR2(T) and G. tropica CL-CB462(T) was 6.7 % (reciprocal 9.5 %). Strain CL-KR2(T) grew in the presence of 1-20 % sea salts and the optimal salt concentration was 3.5-5 %. The temperature and pH optima for growth were 35 °C and pH 7.5. The major cellular fatty acids (≥10.0 %) of strain CL-KR2(T) were iso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) and iso-C17 : 1ω9c and the only isoprenoid quinone was MK-7. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, two unidentified glycolipids and two unidentified lipids. The genomic DNA G+C content of strain CL-KR2(T) was 43.2 mol%. The combined phenotypic, chemotaxonomic and phylogenetic data showed that strain CL-KR2(T) could be distinguished from the only member of the genus Gracilimonas with a validly published name. Thus, strain CL-KR2(T) should be assigned to a novel species in the genus Gracilimonas, for which the name Gracilimonas rosea sp. nov. is proposed. The type strain is CL-KR2(T) ( = KCCM 90206(T) = JCM 18898(T)).

Nocardioides salsibiostraticola sp. nov., isolated from biofilm formed in coastal seawater.

A Gram-staining-positive, non-motile, aerobic, non-spore-forming and short rod-shaped bacterial strain, PAMC 26527(T), was isolated from biofilm formed in coastal seawater of the Norwegian Sea. Analysis of the 16S rRNA gene sequence of strain PAMC 26527(T) revealed a clear affiliation with the genus Nocardioides. Based on phylogenetic analysis, strain PAMC 26527(T) showed the closest phylogenetic relationship with Nocardioides caricicola YC6903(T) with 16S rRNA gene sequence similarity of 96.3 %. Strain PAMC 26527(T) grew in the presence of 0-5.0 % sea salts. The optimum temperature and pH for growth were 20 °C and pH 7.5. The major cellular fatty acids of strain PAMC 26527(T) were iso-C16 : 0, C17 : 1ω8c and C18 : 1ω9c and the major isoprenoid quinone was MK-8(H4). Cell-wall analysis showed that strain PAMC 26527(T) contained LL-diaminopimelic acid. The genomic DNA G+C content was 69.3 mol%. The combined phenotypic, chemotaxonomic and phylogenetic data showed that strain PAMC 26527(T) could be clearly distinguished from recognized members of the genus Nocardioides. Thus, strain PAMC 26527(T) should be classified as representing a novel species in the genus Nocardioides, for which the name Nocardioides salsibiostraticola sp. nov. is proposed. The type strain is PAMC 26527(T) ( = KCTC 29158(T) = JCM 18743(T)).

Pontimonas salivibrio gen. nov., sp. nov., a new member of the family Microbacteriaceae isolated from a seawater reservoir of a solar saltern.

A Gram-staining-positive, non-motile, strictly aerobic, non-spore-forming, vibrio-shaped bacterial strain, CL-TW6(T), was isolated from a reservoir seawater sample from a solar saltern in Korea. Analysis of the 16S rRNA gene sequence of strain CL-TW6(T) revealed a clear affiliation with the family Microbacteriaceae. Strain CL-TW6(T) showed the closest phylogenetic relationships with the genera Yonghaparkia and Microcella, with 16S rRNA gene sequence similarity of 94.8-95.3%. The strain grew in the presence of 1-9% sea salts, at 15-35 °C and at pH 7.0-9.0. The major cellular fatty acids of strain CL-TW6(T) were anteiso-C15:0 (32.6%), iso-C16:0 (20.4%), iso-C15:0 (13.2%) and iso-C14:0 (11.8%) and the major menaquinones were MK-9 and MK-10. Cell-wall analysis showed that the peptidoglycan of strain CL-TW6(T) contained 2,4-diaminobutyric acid, alanine, glycine and glutamic acid. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The genomic DNA G+C content of strain CL-TW6(T) was 60.0 mol%. The combined phenotypic, chemotaxonomic and phylogenetic data showed clearly that strain CL-TW6(T) could be distinguished from members of the family Microbacteriaceae with validly published names. Thus, strain CL-TW6(T) should be classified as representing a novel genus and species in the family Microbacteriaceae, for which the name Pontimonas salivibrio gen. nov., sp. nov. is proposed. The type strain of Pontimonas salivibrio is CL-TW6(T) (=KCCM 90105(T) =JCM 18206(T)).

Nocardioides marinquilinus sp. nov., isolated from coastal seawater.

A Gram-stain-positive, non-motile, strictly aerobic, non-spore-forming and short rod-shaped bacterial strain, CL-GY44(T), was isolated from coastal seawater, Korea. Analysis of the 16S rRNA gene sequence of strain CL-GY44(T) revealed a clear affiliation with the genus Nocardioides. Based on phylogenetic analysis, strain CL-GY44(T) showed the closest phylogenetic relationship with Nocardioides ginsengagri BX5-10(T) and Nocardioides plantarum NCIMB 12834(T). Strain CL-GY44(T) was not able to grow in the presence of NaCl but grew with 0-5.5 % sea salts. The optimum temperature and pH for growth were 30 °C and pH 7.0. The major cellular fatty acids of strain CL-GY44(T) were C17 : 1ω6c, iso-C16 : 0, C16 : 0 and iso-C15 : 0 and the major menaquinone was MK-8(H4). The cell-wall analysis showed that strain CL-GY44(T) contained ll-diaminopimelic acid. The genomic DNA G+C content was 71.6 mol%. The combined phenotypic, chemotaxonomic and phylogenetic data showed that strain CL-GY44(T) could be clearly distinguished from members of the genus Nocardioides. Thus, strain CL-GY44(T) should be classified as representing a novel species in the genus Nocardioides, for which the name Nocardioides marinquilinus sp. nov. is proposed. The type strain is CL-GY44(T) ( = KCCM 90109(T) = JCM 18459(T)).

Description of Spongiibacter borealis sp. nov., isolated from Arctic seawater, and reclassification of Melitea salexigens Urios et al. 2008 as a later heterotypic synonym of Spongiibacter marinus Graeber et al. 2008 with emended descriptions of the genus Spongiibacter and Spongiibacter marinus.

A Gram-negative, rod-shaped and motile strain, designated CL-AS9(T), was isolated from polar seawater of the Arctic. Analysis of the 16S rRNA gene sequence of the strain showed an affiliation with the genus Spongiibacter, sharing 93.9% and 93.7% sequence similarities with the type strains of Spongiibacter tropicus CL-CB221(T) and Spongiibacter marinus HAL40b(T), respectively. Phylogenetic analyses revealed that strain CL-AS9(T) formed a separate branch that was distinct from a clade comprising Spongiibacter marinus HAL40b(T), Spongiibacter tropicus CL-CB221(T) and Melitea salexigens 5IX/A01/131(T). Cells of the strain grew optimally at 20-25 °C and pH 6.6-8.0 in the presence of 3-4% (w/v) sea salts. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unidentified aminophospholipid. The major quinone was ubiquinone 8. The major cellular fatty acids were C(16:1)ω7c and/or iso-C(15:0) 2-OH (23.1%), C(17:1)ω8c (22.1%) and C(18:1)ω7c (15.6%). The genomic DNA G+C content was 53.6 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data presented, we propose the name Spongiibacter borealis sp. nov. with the type strain CL-AS9(T) (=KCCM 90094(T) =JCM 17304(T)) and the reclassification of Melitea salexigens as a later heterotypic synonym of Spongiibacter marinus. We also provide emended descriptions of the genus Spongiibacter and Spongiibacter marinus.