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A novel extremely halophilic archaeon, strain RHB-C T , was isolated from a saturated brine pond of a solar saltern in Bolinao, Pangasinan, Philippines. Colonies were orange-red-pigmented, smooth, convex and round on a solid modified growth medium containing 25 % (w/v) of total salts. Cells of strain RHB-C T on the solid modified growth medium were ovoid-shaped (0.89-2.66 µm long), while the cells in a liquid modified growth medium were rod-shaped (1.53-5.65 µm long and 0.45-1.03 µm wide). The strain was Gram-stain-negative, motile and strictly aerobic. Strain RHB-C T grew with NaCl concentrations ranging from 10 to 30 % (w/v; optimum, 20-25 %), at pH 6.5-8.5 (optimum, pH 7.0-7.5) and at 20-55 °C (optimum, 40-45 °C). Furthermore, the strain grew even in the absence of Mg 2+ ; however, when supplemented with Mg 2+ , growth was observed optimally at 0.2-0.4 M Mg 2+ . The 16S rRNA gene phylogeny inferred that the strain is a member of the genus Halorubrum and was related to Halorubrum xinjiangense CGMCC 1.3527 T (99.0 %), Halorubrum sodomense DSM 3755 T (98.8 %), Halorubrum coriense Ch2 T (98.8 %), Halorubrum trapanicum NRC 34021 T (98.4 %) and Halorubrum distributum JCM 9100 T (98.1 %). The rpoB ' gene sequences also showed that strain RHB-C T is related to Hrr. xinjiangense JCM 12388 T (97.1 %), Hrr. distributum JCM 9100 T (97.1 %), Hrr. coriense JCM 9275 T (96.5 %), Hrr. californiense JCM 14715 T (96.5 %), Hrr. trapanicum JCM 10477 T (96.3%), Hrr. sodomense JCM 8880 T (96.2%) and Hrr. tebenquichense DSM 14210 T (95.6 %). The DNA G+C content of strain RHB-C T was 68.7 mol% (genome). Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain RHB-C T and the closely related species of Halorubrum were below 40 and 90 %, respectively, which are far below the thresholds to delineate a new species. The polar lipids of strain RHB-C T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulphate and sulfated mannosyl glycosyl diether. Based on dDDH and ANI values, and the significant morphological and physiological differences from known taxa, it is hereby suggested that strain RHB-C T represents a novel species of the genus Halorubrum , for which the name Halorubrum salinarum sp. nov. is proposed. The type strain is RHB-C T (=KCTC 4274 T =CMS 2103 T ).

A Gram-stain-negative, aerobic, rod-shaped strain (R2A-3 T ) was isolated from the toxin-producing dinoflagellate Centrodinium punctatum and identified as a novel genus and new species based on a polyphasic taxonomic approach. The optimum conditions for growth of the strain were at 25 °C, pH 8.0 and in the presence of 3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA genes and 92 core genes sets revealed that strain R2A-3 T belongs to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. The 16S rRNA gene of strain R2A-3 T showed the highest sequence similarity to Polycyclovorans algicola TG408 T (95.2%), Fontimonas thermophila HA-01 T (94.1%) and Sinimarinibacterium flocculans NH6-24 T (93.2%), and less than 92.8 % similarity to other genera in the family Nevskiaceae . The genome length of strain R2A-3 T was 3608892 bp with 65.2 mol% G+C content. Summed feature 8 (comprising C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ) was the major fatty acid (>10 %). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were detected as the major polar lipids. The major respiratory quinone was ubiquinone-8. According to its phylogenetic, phenotypic, chemotaxonomic and genomic features, strain R2A-3 T represents a new species in the new genus of the family Nevskiaceae . It is recommended to name it Flagellatimonas centrodinii gen. nov., sp. nov. The type strain is R2A-3 T (=KCTC 82469 T =GDMCC 1.2523 T ).

An aerobic, Gram-stain-negative, weak-motile, short-rod-shaped bacterial strain, designated JBR3-12 T , was isolated from halophyte Carex pumila plants, and its taxonomic position was investigated by using a polyphasic taxonomic approach. The strain produced a pink pigment on tryptic soy agar and grew optimally at 25 °C, pH 8 and in the presence of 3 % (w/v) NaCl. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain JBR3-12 T formed a lineage within the genus Pedobacter and was most closely related to Pedobacter sandarakinus DS-27 T (98.0 %) and Pedobacter agri PB92 T (97.6 %). The DNA G+C content of the genome was 41.3 mol%; the whole genome length was 5 426 070 bp. The major fatty acids of JBR3-12 T were iso-C 15 : 0 , summed feature 3 (comprising C 16 : 1  ω 6 c and/or C 16 : 1  ω 7 c ) and iso-C 17 : 0 3-OH. The predominant polar lipid was phosphatidylethanolamine. The predominant quinone was menaquinone-7. Based on its phenotypic, phylogenetic and genotypic features, strain JBR3-12 T is proposed to represent a novel species of the genus Pedobacter , for which the name is Pedobacter endophyticus sp. nov. The type strain is JBR3-12 T (=KCTC 82363 T =NBRC 114901 T ).

In the current circumscription, the Thoracosphaeraceae comprise all dinophytes exhibiting calcified coccoid cells produced during their life-history. Species hitherto assigned to Ensiculifera and Pentapharsodinium are mostly based on the monadoid stage of life-history, while the link to the coccoid stage (occasionally treated taxonomically distinct) is not always resolved. We investigated the different life-history stages and DNA sequence data of Ensiculifera mexicana and other species occurring in samples collected from all over the world. Based on concatenated ribosomal RNA gene sequences Ensiculiferaceae represented a distinct peridinalean branch, which showed a distant relationship to other calcareous dinophytes. Both molecular and morphological data (particularly of the coccoid stage) revealed the presence of three distinct clades within Ensiculiferaceae, which may include other dinophytes exhibiting a parasitic life-history stage. At a higher taxonomic level, Ensiculiferaceae showed relationships to parasites and endosymbionts (i.e., Blastodinium and Zooxanthella) as well as to dinophytes harbouring diatoms instead of chloroplasts. These unexpected phylogenetic relationships are corroborated by the presence of five cingular plates in all such taxa, which differs from the six cingular plates of most other Thoracosphaeraceae. We herein describe Ensiculiferaceae, emend the descriptions of Ensiculifera and Pentapharsodinium, erect Matsuokaea and provide several new combinations at the species level., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Investigation of phytoplankton from East China Sea of the Pacific Ocean, offshore Réunion Island of the Indian Ocean, and the French Atlantic coast revealed a species of poorly known armored fusiform dinoflagellate. To clarify this species, morphology and phylogeny based on mitochondrial and nuclear protein gene sequence (Cox1, Cob and Hsp90) concatenated with the SSU, ITS region and LSU rDNA sequences were analysed. Epifluorescence and scanning electron microscopy observations revealed that the nucleus of the specimen was elongated, sausage-shaped and located equatorially on the left lateral side of the cell, and that the plate formula is Po, 3', 1a, 6″, 6C, 8S, 5‴, 1p, 2'‴. These morphological features indicate that the species can be assigned to Centrodinium punctatum. Interestingly, the phylogenetic analyses placed this species within the Alexandrium clade, with Alexandrium affine being its closest relative. This indicates that genus Alexandrium is not monophyletic. The most similar morphological traits between C. punctatum and Alexandrium species were the shape of apical pore plate and the arrangement of the sulcal plates. However, since there are significant morphological differences between C. punctatum and Alexandrium species, further studies are needed to clarify the relation between the morphology and molecular phylogeny of other Centrodinium-related fusiform species., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

SUMMARY An unarmored dinoflagellate, Karlodinium jejuense sp. nov., was isolated from the northern East China Sea. The species was characterized by light, fluorescence, and scanning electron microscopy of laboratory cultures, as well as SSU rDNA, ITS region (ITS1‐5.8S‐ITS2) and LSU rDNA gene sequences. Cells were ellipsoid to oval, small‐sized, 9.9–16.0 μm in length and 6.2–12.7 μm in width. The chloroplasts were 7–10 in number and yellow‐green in color. The central nucleus was large, located in the center of the cell. The linear apical groove with outward thick rolled margins was very short, and there was no ventral pore. Small pores were irregularly distributed on the cell surface. The amphiesmal vesicles were hexagonal and pentagonal. Karlodinium jejuense was morphologically similar to K. ballantinum but differed in cell surface characteristics and swimming pattern. The partial LSU sequence of K. jejuense differed by 3.7–4.1% from that of K. ballantinum. Molecular phylogenetic analyses of multi‐gene sequences revealed that K. jejuense was an independent species nested within the Karlodinium clade. Phylogenetic analysis based on partial LSU rDNA gene sequences indicated that K. jejuense was most closely related to K. gentienii and K. ballantinum. [ABSTRACT FROM AUTHOR]

• Ellipsoidal alexandrium cysts in jinhae-masan bay are produced by two species, alexandrium catenella (Group I) and A. pacificum (Group IV). • Cyst germination temperature is lower for alexandrium catenella (Group I) than for A. pacificum (Group IV). • Differences in cyst germination rates among sampling sites can be determined by the differences in distribution and abundance of the species. • Concentrations of ellipsoidal alexandrium cysts from surface sediments of jinhae-masan bay are higher in february than in august. • PST profiles of alexandrium catenella (Group I) and A. pacificum (Group IV) in jinhae-masan bay are dominated by GTX-3 and GTX-4. To better understand the outbreaks of paralytic shellfish poisoning and bloom dynamics caused by Alexandrium species in Jinhae-Masan Bay, Korea, the germination and distributions of ellipsoidal Alexandrium cysts were investigated, and paralytic shellfish toxins (PSTs) profiles and contents were determined using strains established from germling cells. The phylogeny and morphological observations revealed that the germinated vegetative cells from ellipsoidal cysts collected from the surface sediments in Jinhae-Masan Bay belong to Alexandrium catenella (Group I) and A. pacificum (Group IV) nested within A. tamarense species complex. Cyst germinations of A. catenella (Group I) were observed at only 10 °C, whereas cysts of A. pacificum (Group IV) could germinate at temperature ranges of 10 to 25 °C. Maximum germination success (85%) for isolated cysts occurred at 15 °C, and the germling cells were A. pacificum (Group IV). The results indicate that the variation in water temperature in Jinhae-Masan Bay can control the seasonal variations in germination of cysts of A. catenella (Group I) and A. pacificum (Group IV). The germination rates of ellipsoidal Alexandrium cysts were different among sampling sites in Jinhae-Masan Bay, probably because of differences in distribution and abundance of A. catenella (Group I) and A. pacificum (Group IV) in the sediments. The ellipsoidal Alexandrium cyst concentrations were much higher in February than in August, however the distributions were similar. Gonyautoxins 3 and 4 (GTX-3 and GTX-4) contributed a large proportion (>90%) of the toxins produced by strains A. catenella (Group I) and A. pacificum (Group IV) established from germling cells, and the total cellular contents were higher in A. catenella (Group I) than in A. pacificum (Group IV). [ABSTRACT FROM AUTHOR]

Dense patches were observed in the tidal pools of the southern area of Korea. To clarify the causative organisms, the cells were collected and their morphological features were examined using light and scanning electron microscopy (SEM). In addition, after establishing strains for the cells the molecular phylogeny was inferred with concatenated small subunit (SSU) and large subunit (LSU) rRNA sequences. The cells were characterized by a nucleus in the hypotheca, strong reticulations in thecal plates, the separation of plates 2a and 3a, the tear-shaped apical pore complex, an elongated rectangular 1a plate and the absence of the right sulcal list. The thecal plate formula was Po, X, 4′, 3a, 7″, 6c, 4S, 5′′′, 2′′′′. Based on these morphological features, the cells were identified as Bysmatrum subsalsum. In the culture, the spherical cysts of B. subsalsum without thecal plates were observed. Molecular phylogeny revealed two ribotypes of B. subsalsum are identified; The Korean isolates were nested within the ribotype B consisting of the isolates from China, Malaysia and the French Atlantic, whereas the ribotype A includes only the isolates from the Mediterranean Sea. In the phylogeny, B. subsalsum and B. austrafrum were grouped. This can be supported by the morphological similarity between the two species, indicating that the two species may be conspecific, however B. subsalsum may distinguish from B. austrafrum, because of differences in the types of eyespots reported in previous studies. These findings support the idea that there is cryptic diversity within B. subsalsum. [ABSTRACT FROM AUTHOR]

The potentially harmful species Alexandrium insuetum established by the incubation of resting cysts isolated from sediment trap samples collected at Jinhae-Masan Bay, Korea was characterized by morphological and phylogenetic analysis. The effects of temperature and salinity on the growth of A. insuetum were also investigated. The resting cysts are characterized by a spherical shape, a small size (20–25 μm) and the presence of either three or four red accumulation bodies. The similarity of morphological features of the resting cysts to those of other species of the minutum group (consisting of Alexandrium minutum and A. tamutum ) indicates that the morphological features of resting cysts might improve the accuracy of the grouping of Alexandrium species. A. insuetum germinated from the resting cysts is morphologically consistent with vegetative cells reported from Korean and Japanese coastal areas, and has an partial large subunit (LSU) rDNA sequence identical to that from Japanese strains. The growth of A. insuetum was observed between salinity 20 and 35, with increasing temperature; however at 25 °C, A. insuetum could grow even at the salinity of 15. The highest growth rate (0.60 d −1 ) was observed at 25 °C and the salinity of 25, which is higher than the previously reported growth rate of A. tamarense , which is responsible for outbreaks of paralytic shellfish poisoining and blooms in Jinhae-Masan Bay. These results suggest that the proliferation of A. insuetum in Jinhae-Masan Bay is likely to be highest during the summer. [ABSTRACT FROM AUTHOR]