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1.
Protist ; 170(1): 82-103, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30797136

RESUMO

Perkinsozoa is an exclusively parasitic group within the alveolates and infections have been reported from various organisms, including marine shellfish, marine dinoflagellates, freshwater cryptophytes, and tadpoles. Despite its high abundance and great genetic diversity revealed by recent environmental rDNA sequencing studies, Perkinsozoa biodiversity remains poorly understood. During the intensive samplings in Korean coastal waters during June 2017, a new parasitoid of dinoflagellates was detected and was successfully established in culture. The new parasitoid was most characterized by the presence of two to four dome-shaped, short germ tubes in the sporangium. The opened germ tubes were biconvex lens-shaped in the top view and were characterized by numerous wrinkles around their openings. Phylogenetic analyses based on the concatenated SSU and LSU rDNA sequences revealed that the new parasitoid was included in the family Parviluciferaceae, in which all members were comprised of two separate clades, one containing Parvilucifera species (P. infectans, P. corolla, and P. rostrata), and the other containing Dinovorax pyriformis, Snorkelia spp., and the new parasitoid from this study. Based on morphological, ultrastructural, and molecular data, we propose to erect a new genus and species, Tuberlatum coatsi gen. n., sp. n., from the new parasitoid found in this study. Further, we examined and discussed the validity of some diagnostic characteristics reported for parasitoids in the family Parviluciferaceae at both the genus and species levels.


Assuntos
Alveolados/classificação , Alveolados/fisiologia , Dinoflagelados/parasitologia , Alveolados/citologia , Alveolados/ultraestrutura , Dinoflagelados/citologia , Dinoflagelados/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia , RNA de Algas/análise , RNA de Protozoário/análise , República da Coreia , Análise de Sequência de RNA
2.
Harmful Algae ; 80: 140-148, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30502806

RESUMO

The benthic dinoflagellate Prorocentrum hoffmannianum M.A. Faust is typical of tropical warm waters and produces biotoxins responsible for diarrhetic shellfish poisoning (DSP). In this study, the effect of temperature and nutrient limitation on growth and toxin production of P. hoffmannianum isolated from field samples collected in the Florida Keys was investigated. Batch culture experiments were ran at two temperatures (i.e. 21 ± 0.1 and 27 ± 0.1 °C) and under nitrogen-limited (14.7 µmol L-1 N-NO3- and 18.1 µmol L-1 P-PO43-) and phosphorus-limited (441 µmol L-1 N-NO3- and 0.6 µmol L-1 P-PO43-) levels with respect to control nutrient conditions (441 µmol L-1 N-NO3-and 18.1 µmol L-1 P-PO43-). Both temperature and nutrient conditions significantly affected growth rates and maximum yield of P. hoffmannianum with the maximum values being recorded at the higher temperature and in the replete medium. Production of okadaic acid was induced under all conditions (from 13.5 to 859.8 pg cell-1), with values up to one order of magnitude higher than those observed in other DSP toxin producing species. Toxin production was enhanced under P limitation at 27 °C, corroborating the theory that toxin production is modulated by cell physiological conditions, which are in turn affected by a wide spectrum of factors, including environmental stressors such as nutrient availability. Toxin fraction released in the growth medium was negligible. No okadaic acid esters were detected in this strain of P. hoffmannianum.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Nutrientes , Temperatura Ambiente , Dinoflagelados/fisiologia , Dinoflagelados/ultraestrutura , Florida , Nitrogênio/metabolismo , Ácido Okadáico/metabolismo , Fósforo/metabolismo , Estresse Fisiológico
3.
Harmful Algae ; 80: 149-157, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30502807

RESUMO

The genus Gambierdiscus produces ciguatera toxins, which has led to extensive studies of this genus. Epiphytic dinoflagellate cells were isolated from coralline macroalgae collected from the coastal waters of Jeju Island, Korea, and two clonal cultures were established. The morphology of these cells was examined using light and scanning electron microscopy, and the sequences of the small subunit (SSU), large subunit (LSU), and internal transcribed spacer (ITS) region of rDNA were determined. The phylogenetic trees based on SSU, LSU (D1-D3), and LSU (D8-D10) rDNA showed the two Korean isolates forming a clade with unidentified strains named Gambierdiscus sp. type 2. This clade showed a clear divergence from the two closest clades containing of the G. caribaeus and G. carpenteri strains. Morphologically, the Korean isolates had an anteroposteriorly compressed cell shape having a smooth theca ornamentation. Growth of the Korean isolates ceased when water temperatures were <20 °C or >30 °C with an optimum at 26 °C. This temperature preference may account for why Gambierdiscus sp. type 2 has only been isolated from the temperate waters of Korea and Japan. However, the two most closely related species G. caribaeus and G. carpenteri have broader temperature ranges tolerating as high as 34-36 °C and are globally distributed. Based on these results, the Korean isolates are proposed as a new species in the genus Gambierdiscus and named Gambierdiscus jejuensis sp. nov. Furthermore, it is suggested that the unidentified strains belonging to the Gambierdiscus sp. type 2 be transferred to the new species, G. jejuensis.


Assuntos
Dinoflagelados/classificação , Temperatura Ambiente , Ciguatoxinas , Demografia , Dinoflagelados/fisiologia , Dinoflagelados/ultraestrutura , Ilhas , Filogenia , Filogeografia , República da Coreia
4.
J Phycol ; 54(6): 923-928, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30276824

RESUMO

The planktonic phototrophic dinoflagellate Gonyaulax whaseongensis sp. nov., isolated from coastal waters of western Korea, was described from living and fixed cells under light and scanning electron microscopy, and its rDNA was sequenced. Gonyaulax whaseongensis had a plate formula of 2pr, 4', 6'', 6c, 6''', 1p, and 1'''' with S-type ventral organization like the other species in the genus. However, this dinoflagellate had a narrow cingulum (ca. 2.6 µm), small displacement of the cingulum, slight overhang and steep angle between the ends of the cingulum, quadrangular sixth precingular plate, reticulated cell surface without longitudinal lines or ridges, and two unequal antapical spines, together which distinguish this from all other reported Gonyaulax species. In addition, the SSU and LSU rDNA sequences were 8%-12% and 11%-24%, respectively, different from those of Gonyaulax polygramma, Gonyaulax spinifera, Gonyaulax fragilis, Gonyaulax membranacea, and Gonyaulax digitale, the putatively closest related species in the phylogenetic analysis.


Assuntos
Dinoflagelados/classificação , DNA de Algas/análise , DNA de Protozoário/análise , DNA Ribossômico/análise , Dinoflagelados/citologia , Dinoflagelados/genética , Dinoflagelados/ultraestrutura , Microscopia Eletrônica de Varredura , República da Coreia , Análise de Sequência de DNA
5.
J Phycol ; 54(5): 744-761, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30144373

RESUMO

The genus Gymnodinium includes many morphologically similar species, but molecular phylogenies show that it is polyphyletic. Eight strains of Gymnodinium impudicum, Gymnodinium dorsalisulcum and a novel Gymnodinium-like species from Chinese and Malaysian waters and the Mediterranean Sea were established. All of these strains were examined with light microscopy, scanning electron microscopy and transmission electron microscopy. SSU, LSU and internal transcribed spacers rDNA sequences were obtained. A new genus, Wangodinium, was erected to incorporate strains with a loop-shaped apical structure complex (ASC) comprising two rows of amphiesmal vesicles, here referred to as a new type of ASC. The chloroplasts of Wangodinium sinense are enveloped by two membranes. Pigment analysis shows that peridinin is the main accessory pigment in W. sinense. Wangodinium differs from other genera mainly in its unique ASC, and additionally differs from Gymnodinium in the absence of nuclear chambers, and from Lepidodinium in the absence of Chl b and nuclear chambers. New morphological information was provided for G. dorsalisulcum and G. impudicum, e.g., a short sulcal intrusion in G. dorsalisulcum; nuclear chambers in G. impudicum and G. dorsalisulcum; and a chloroplast enveloped by two membranes in G. impudicum. Molecular phylogeny was inferred using maximum likelihood and Bayesian inference with independent SSU and LSU rDNA sequences. Our results support the classification of Wangodinium within the Gymnodiniales sensu stricto clade and it is close to Lepidodinium. Our results also support the close relationship among G. dorsalisulcum, G. impudicum, and Barrufeta. Further research is needed to assign these Gymnodinium species to Barrufeta or to erect new genera.


Assuntos
Dinoflagelados/citologia , Dinoflagelados/genética , Filogenia , China , Cloroplastos/ultraestrutura , DNA de Algas/análise , DNA de Protozoário/análise , DNA Ribossômico/análise , Dinoflagelados/classificação , Dinoflagelados/ultraestrutura , França , Malásia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
6.
Protist ; 169(3): 333-350, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29864699

RESUMO

This study describes a novel species of Haplozoon, H. ezoense n. sp., a dinoflagellate parasite isolated from the intestines of Praxillella pacifica (Polychaeta). Trophonts (feeding stages) of H. ezoense n. sp. were isolated and studied with scanning and transmission electron microscopy, and molecular phylogenetic analyses was performed using 18S rDNA and 28S rDNA. Trophonts had an average length of 120µm, and were linear, forming a single longitudinal row comprising a trophocyte with a stylet, an average of 14 gonocytes (width=10µm), and bulbous cells that we concluded were likely sporocytes. The surface of H. ezoense n. sp. was covered with projections of the amphiesma. Sections viewed under TEM revealed multiple triple membrane-bound organelles reminiscent of relic non-photosynthetic plastids within the gonocytes. Haplozoon ezoense n. sp., H. praxillellae, and H. axiothellae formed a well-supported clade in the 18S rDNA datasets. The sequences of H. ezoense n. sp. differed from H. praxillellae, a species of Haplozoon isolated from the same host species in the Northeast Pacific, at 88/1,748 bases; and 155/1,752 bases from H. axiothellae. Concatenated 18S rDNA and 28S rDNA datasets were unable to resolve the deeper relationships of Haplozoon in the context of dinoflagellates.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/isolamento & purificação , Filogenia , Plastídeos/ultraestrutura , Animais , Análise por Conglomerados , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dinoflagelados/genética , Dinoflagelados/ultraestrutura , Trato Gastrointestinal/parasitologia , Estudos Longitudinais , Microscopia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Poliquetos/parasitologia , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Análise de Sequência de DNA
7.
Harmful Algae ; 74: 78-97, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29724345

RESUMO

Species of Fukuyoa, recently revised from the globular Gambierdiscus, are toxic benthic dinoflagellates associated with ciguatera. In this study, a total of ten strains of Fukuyoa collected from Hong Kong waters were characterized using morphological and phylogenetic analyses. Results from both analyses showed that one of the strains is a putative new species, namely Fukuyoa sp. HK Type 1 (plate formula Po, 3', 7″, 6c, 7s, 5‴, 1p and 2'‴ with a distinctive small and narrow cell shape, narrow Po plate, high Po pore density, large and broad Plate 1' but small and round Po pore size, small and narrow Plate 2', long and narrow Plates 2'‴ and 1p), and the others were F. ruetzleri. This is the first report of these two species of Fukuyoa in the South China Sea and Asia-Pacific region. Phylogenies on 18S, 28S D1/D3 and D8/D10 ribosomal DNA sequences strongly support that Fukuyoa sp. HK Type 1 is currently the most divergent species in the genus Fukuyoa. The diagrammatic plots on the p-distance matrices of 18S, 28S D1/D3 and D8/D10 and ITS regions resolved that the species of Fukuyoa were separated into three main groups, i.e., Fukuyoa sp. HK Type 1, F. paulensis and a group consisting of F. ruetzleri, F. yasumotoi and F. cf. yasumotoi, while Fukuyoa sp. HK Type 1 was always the most distant from the other two groups. Additionally, the pairwise p-distance values calculated based on the ITS region have always been the highest for pairs between Fukuyoa sp. HK Type 1 and other Fukuyoa species, ranging from 0.142 to 0.150. Our molecular results suggested that Fukuyoa sp. HK Type 1 is a putative new species. Both morphological and molecular data of more strains from different localities should be, however, collected to address its intraspecific variability and further evaluate its taxonomic status. A bioassay analysis demonstrated that algal lysates extracted from F. ruetzleri and Fukuyoa sp. HK Type 1 were lethal to brine shrimp larvae, indicating that both species were toxic. Bulk cultures were tested for Pacific ciguatoxins (P-CTXs) and maitotoxins (MTXs) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). All isolates of Fukuyoa produced neither P-CTXs nor MTX-1, but isolates of F. ruetzleri produced a compound putatively assigned as MTX-3. This study has updated the current biodiversity and distribution of the toxic benthic dinoflagellates Fukuyoa, and thus contributes to the understanding of their emerging threats to the sub-tropical reef systems locally and regionally.


Assuntos
Artemia/efeitos dos fármacos , Dinoflagelados/química , Dinoflagelados/classificação , Animais , Cromatografia Líquida , Recifes de Corais , DNA de Algas/análise , Dinoflagelados/citologia , Dinoflagelados/ultraestrutura , Hong Kong , Microscopia Eletrônica de Varredura , Oceanos e Mares , Filogenia , RNA Ribossômico 18S/análise , RNA Ribossômico 28S/análise , Espectrometria de Massas em Tandem , Testes de Toxicidade Aguda
8.
Mar Pollut Bull ; 128: 390-395, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29571387

RESUMO

From December 2016 to May 2017, 22 phytoplankton surface samples were collected with a 20-µm mesh net at three islands of the Archipiélago de Revillagigedo (Partida, Socorro and San Benedicto), Mexican Pacific. The sites depth was approximately 20-80 m; the surface water temperature was 21-27 °C. The potentially toxic benthic dinoflagellate Ostreopsis lenticularis was present in all the samples. Cells had a lenticular to broadly oval shape, 65-100 µm long and 50-80 µm wide. The taxonomy of the genus Ostreopsis has been unclear due to equivocal ascribing some taxonomic features among species. The identification of specimens from the archipelago was made based on the most important taxonomic characteristics: the thecal plates, the presence of two types of thecal pores (larger and smaller), and the lack of cingulum undulation. The studied cells are compared with O. cf. siamensis, O. labens and O. marina. This is the first record of the species in the archipelago waters.


Assuntos
Dinoflagelados/isolamento & purificação , Monitoramento Ambiental/métodos , Água do Mar/química , Biodiversidade , Dinoflagelados/classificação , Dinoflagelados/ultraestrutura , México , Ilhas do Pacífico , Oceano Pacífico , Temperatura Ambiente
9.
Harmful Algae ; 71: 57-77, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29306397

RESUMO

Strains of a dinoflagellate from the Salton Sea, previously identified as Protoceratium reticulatum and yessotoxin producing, have been reexamined morphologically and genetically and Pentaplacodinium saltonense n. gen. et sp. is erected to accommodate this species. Pentaplacodinium saltonense differs from Protoceratium reticulatum (Claparède et Lachmann 1859) Bütschli 1885 in the number of precingular plates (five vs. six), cingular displacement (two widths vs. one), and distinct cyst morphology. Incubation experiments (excystment and encystment) show that the resting cyst of Pentaplacodinium saltonense is morphologically most similar to the cyst-defined species Operculodinium israelianum (Rossignol, 1962) Wall (1967) and O. psilatum Wall (1967). Collections of comparative material from around the globe (including Protoceratium reticulatum and the genus Ceratocorys) and single cell PCR were used to clarify molecular phylogenies. Variable regions in the LSU (three new sequences), SSU (12 new sequences) and intergenic ITS 1-2 (14 new sequences) were obtained. These show that Pentaplacodinium saltonense and Protoceratium reticulatum form two distinct clades. Pentaplacodinium saltonense forms a monophyletic clade with several unidentified strains from Malaysia. LSU and SSU rDNA sequences of three species of Ceratocorys (C. armata, C. gourreti, C. horrida) from the Mediterranean and several other unidentified strains from Malaysia form a well-supported sister clade. The unique phylogenetic position of an unidentified strain from Hawaii is also documented and requires further examination. In addition, based on the V9 SSU topology (bootstrap values >80%), specimens from Elands Bay (South Africa), originally described as Gonyaulax grindleyi by Reinecke (1967), cluster with Protoceratium reticulatum. The known range of Pentaplacodinium saltonense is tropical to subtropical, and its cyst is recorded as a fossil in upper Cenozoic sediments. Protoceratium reticulatum and Pentaplacodinium saltonense seem to inhabit different niches: motile stages of these dinoflagellates have not been found in the same plankton sample.


Assuntos
Dinoflagelados/classificação , California , DNA de Algas/análise , DNA de Protozoário/análise , DNA Ribossômico , Dinoflagelados/genética , Dinoflagelados/ultraestrutura , Genes de Protozoários , Microscopia Eletrônica de Varredura , Filogenia , Análise de Sequência de DNA
10.
J Microsc ; 270(1): 83-91, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29064560

RESUMO

The symbiotic relationship between corals and Symbiodinium spp. is the key to the success and survival of coral reef ecosystems the world over. Nutrient exchange and chemical communication between the two partners provides the foundation of this key relationship, yet we are far from a complete understanding of these processes. This is due, in part, to the difficulties associated with studying an intracellular symbiosis at the small spatial scales required to elucidate metabolic interactions between the two partners. This feasibility study, which accompanied a more extensive investigation of fixed Symbiodinium cells (data unpublished), examines the potential of using synchrotron radiation infrared microspectroscopy (SR-IRM) for exploring metabolite localisation within a single Symbiodinium cell. In doing so, three chemically distinct subcellular regions of a single Symbiodinium cell were established and correlated to cellular function based on assignment of diagnostic chemical classes.


Assuntos
Fatores Biológicos/análise , Dinoflagelados/química , Dinoflagelados/ultraestrutura , Microscopia/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Estudos de Viabilidade
11.
J Phycol ; 54(1): 126-137, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29194622

RESUMO

The family Ceratocoryaceae includes the genera Ceratocorys, Protoceratium, and Schuettiella, whose phylogenetic relationships are poorly known. Here, the new non-yessotoxin-producing species of the genus Ceratocorys, Ceratocorys mariaovidiorum sp. nov., previously reported as the toxic Protoceratium reticulatum, is described from examinations by light and scanning electron microscopy, molecular phylogeny, and toxin analyses. The species description is made from culture samples of strains CCMP1740 and CCMP404 from USA waters. Ceratocorys mariaovidiorum is globular and has thick and strongly reticulated plates with one pore within each reticule, just like P. reticulatum, but the key difference between the two species is the presence of five precingular plates in C. mariaovidiorum instead of six as in P. reticulatum. The thecal plate formula is Po, 4', 0a, 5″, 6c, ~7s, 5‴, 0p, 2''''. The apical pore plate is oval with a λ-shaped pore. The first apical plate is narrow with a ventral pore on the right anterior side; it contacts the apical pore plate and its contact with the anterior sulcal plate is slight or absent. The fourth precingular plate of other Gonyaulacales is absent. Ceratocorys mariaovidiorum may have small spines on the second antapical plate. A phylogenetic study based on internal transcribed spacer/5.8SrDNA supports the morphological classification of C. mariaovidiorum as a new species of Ceratocorys and in a different clade from P. reticulatum.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/genética , DNA Espaçador Ribossômico/análise , Dinoflagelados/citologia , Dinoflagelados/ultraestrutura , Microscopia Eletrônica de Varredura , Filogenia , RNA de Algas/análise , RNA de Protozoário/análise , RNA Ribossômico 5,8S/análise , Estados Unidos
12.
J Phycol ; 54(1): 138-149, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29194636

RESUMO

A planktonic-benthic relationship has been described for many dinoflagellate species as part of their ecological strategy to overcome highly variable aquatic environments. Here, the phylogenetically and morphologically related marine dinoflagellates Protoceratium reticulatum and Ceratocorys mariaovidiorum were studied in relation to an unknown benthic life form. In vivo and fixed samples from cultures were analyzed in detail by light and scanning electron microscopy. In both species, a cell type with a morphology different from that of vegetative cells was observed in cultures grown until stationary phase. This cell type was always benthic, swimming sporadically only when it was disturbed. Its main feature included a strong dorsoventral compression. These cells originated from vegetative cells whose protoplasm underwent a progressive flattening, resulting in a gradual detachment of the reticulate and thick thecal plates and the formation of very thin non-reticulated new plates with pores. When returned to fresh full-strength medium, the cells recovered their spherical vegetative-like morphology, including new reticulated thick plates and subsequent cell divisions. The kinetics of flattened cell formation showed that in both species, this cell type increased exponentially until the onset of the culture stationary phase and then decreased. The results of this study are discussed in the context of the planktonic-benthic coupling in dinoflagellate life cycles, including those newly appreciated to be well adapted to the benthic environment.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Chile , Dinoflagelados/citologia , Dinoflagelados/ultraestrutura , Traços de História de Vida , Microscopia Eletrônica de Varredura , Espanha
13.
Harmful Algae ; 68: 128-151, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962975

RESUMO

The genus Amphidinium is an important group of athecated dinoflagellates because of its high abundance in marine habitats, its member's ability to live in a variety of environmental conditions and ability to produce toxins. Furthermore, the genus is of particular interest in the biotechnology field for its potential in the pharmaceutical arena. Taxonomically the there is a history of complication and confusion over the proper identities and placements of Amphidinium species due to high genetic variability coupled with high morphological conservation. Thirteen years has passed since the most recent review of the group, and while many issues were resolved, some remain. The present study used microscopy, phylogenetics of the 28S region of rDNA, secondary structure of the ITS2 region of rDNA, compensatory base change data, and cytotoxicity data from Amphidinium strains collected world-wide to elucidate remaining confusion. This holistic approach using multiple lines of evidence resulted in a more comprehensive understanding of the morphological, ecological, and genetic characteristics that are attributed to organisms belonging to Amphidinium, including six novel species: A. fijiensis, A. magnum, A. paucianulatum, A. pseudomassartii, A. theodori, and A. tomasii.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/citologia , Toxinas Marinhas/biossíntese , Filogenia , Animais , Artemia/efeitos dos fármacos , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Dinoflagelados/ultraestrutura , Funções Verossimilhança , Toxinas Marinhas/toxicidade , Conformação de Ácido Nucleico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Subunidades Ribossômicas Maiores/metabolismo , Especificidade da Espécie
14.
Harmful Algae ; 68: 152-167, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962976

RESUMO

The identification of a new suite of toxins, called azaspiracids (AZA), as the cause of human illnesses after the consumption of shellfish from the Irish west coast in 1995, resulted in interest in understanding the global distribution of these toxins and of species of the small dinoflagellate genus Azadinium, known to produce them. Clonal isolates of four species of Azadinium, A. poporum, A. cuneatum, A. obesum and A. dalianense were obtained from incubated sediment samples collected from Puget Sound, Washington State in 2016. These Azadinium species were identified using morphological characteristics confirmed by molecular phylogeny. Whereas AZA could not be detected in any strains of A. obesum, A. cuneatum and A. dalianense, all four strains of A. poporum produced a new azaspiracid toxin, based on LC-MS analysis, named AZA-59. The presence of AZA-59 was confirmed at low levels in situ using a solid phase resin deployed at several stations along the coastlines of Puget Sound. Using a combination of molecular methods for species detection and solid phase resin deployment to target shellfish monitoring of toxin at high-risk sites, the risk of azaspiracid shellfish poisoning can be minimized.


Assuntos
Dinoflagelados/química , Toxinas Marinhas/toxicidade , Compostos de Espiro/toxicidade , Dinoflagelados/isolamento & purificação , Dinoflagelados/ultraestrutura , Geografia , Funções Verossimilhança , Toxinas Marinhas/química , Conformação de Ácido Nucleico , Filogenia , Compostos de Espiro/química , Washington
15.
Harmful Algae ; 68: 206-216, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962981

RESUMO

This study confirms the presence of the toxigenic benthic dinoflagellates Gambierdiscus belizeanus and Ostreopsis spp. in the central Red Sea. To our knowledge, this is also the first report of these taxa in coastal waters of Saudi Arabia, indicating the potential occurrence of ciguatera fish poisoning (CFP) in that region. During field investigations carried out in 2012 and 2013, a total of 100 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast and examined for the presence of Gambierdiscus and Ostreopsis, two toxigenic dinoflagellate genera commonly observed in coral reef communities around the world. Both Gambierdiscus and Ostreopsis spp. were observed at low densities (<200 cells g-1 wet weight algae). Cell densities of Ostreopsis spp. were significantly higher than Gambierdiscus spp. at most of the sampling sites, and abundances of both genera were negatively correlated with seawater salinity. To assess the potential for ciguatoxicity in this region, several Gambierdiscus isolates were established in culture and examined for species identity and toxicity. All isolates were morphologically and molecularly identified as Gambierdiscus belizeanus. Toxicity analysis of two isolates using the mouse neuroblastoma cell-based assay for ciguatoxins (CTX) confirmed G. belizeanus as a CTX producer, with a maximum toxin content of 6.50±1.14×10-5pg P-CTX-1 eq. cell-1. Compared to Gambierdiscus isolates from other locations, these were low toxicity strains. The low Gambierdiscus densities observed along with their comparatively low toxin contents may explain why CFP is unidentified and unreported in this region. Nevertheless, the presence of these potentially toxigenic dinoflagellate species at multiple sites in the central Red Sea warrants future study on their possible effects on marine food webs and human health in this region.


Assuntos
Intoxicação por Ciguatera/parasitologia , Dinoflagelados/fisiologia , Ciguatoxinas/toxicidade , Dinoflagelados/citologia , Dinoflagelados/ultraestrutura , Geografia , Oceano Índico , Salinidade , Alga Marinha/fisiologia , Análise de Sequência de DNA
16.
Harmful Algae ; 68: 224-239, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962983

RESUMO

Heterotrophic nanoflagellates are ubiquitous and known to be major predators of bacteria. The feeding of free-living heterotrophic nanoflagellates on phytoplankton is poorly understood, although these two components usually co-exist. To investigate the feeding and ecological roles of major heterotrophic nanoflagellates Katablepharis spp., the feeding ability of Katablepharis japonica on bacteria and phytoplankton species and the type of the prey that K. japonica can feed on were explored. Furthermore, the growth and ingestion rates of K. japonica on the dinoflagellate Akashiwo sanguinea-a suitable algal prey item-heterotrophic bacteria, and the cyanobacteria Synechococcus sp., as a function of prey concentration were determined. Among the prey tested, K. japonica ingested heterotrophic bacteria, Synechococcus sp., the prasinophyte Pyramimonas sp., the cryptophytes Rhodomonas salina and Teleaulax sp., the raphidophytes Heterosigma akashiwo and Chattonella ovata, the dinoflagellates Heterocapsa rotundata, Amphidinium carterae, Prorocentrum donghaiense, Alexandrium minutum, Cochlodinium polykrikoides, Gymnodinium catenatum, A. sanguinea, Coolia malayensis, and the ciliate Mesodinium rubrum, however, it did not feed on the dinoflagellates Alexandrium catenella, Gambierdiscus caribaeus, Heterocapsa triquetra, Lingulodinium polyedra, Prorocentrum cordatum, P. micans, and Scrippsiella acuminata and the diatom Skeletonema costatum. Many K. japonica cells attacked and ingested a prey cell together after pecking and rupturing the surface of the prey cell and then uptaking the materials that emerged from the ruptured cell surface. Cells of A. sanguinea supported positive growth of K. japonica, but neither heterotrophic bacteria nor Synechococcus sp. supported growth. The maximum specific growth rate of K. japonica on A. sanguinea was 1.01 d-1. In addition, the maximum ingestion rate of K. japonica for A. sanguinea was 0.13ngC predator-1d-1 (0.06 cells predator-1d-1). The maximum ingestion rate of K. japonica for heterotrophic bacteria was 0.019ngC predator-1d-1 (266 bacteria predator-1d-1), and the highest ingestion rate of K. japonica for Synechococcus sp. at the given prey concentrations of up to ca. 107 cells ml-1 was 0.01ngC predator-1d-1 (48 Synechococcus predator-1d-1). The maximum daily carbon acquisition from A. sanguinea, heterotrophic bacteria, and Synechococcus sp. were 307, 43, and 22%, respectively, of the body carbon of the predator. Thus, low ingestion rates of K. japonica on heterotrophic bacteria and Synechococcus sp. may be responsible for the lack of growth. The results of the present study clearly show that K. japonica is a predator of diverse phytoplankton, including toxic or harmful algae, and may also affect the dynamics of red tides caused by these prey species.


Assuntos
Dinoflagelados/fisiologia , Processos Heterotróficos/fisiologia , Bactérias/metabolismo , Diatomáceas/citologia , Diatomáceas/ultraestrutura , Dinoflagelados/citologia , Dinoflagelados/crescimento & desenvolvimento , Dinoflagelados/ultraestrutura , Comportamento Alimentar
17.
Harmful Algae ; 68: 31-39, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962988

RESUMO

Paralytic shellfish poisoning (PSP) caused the deaths of four people in coastal area of Korea, mainly Jinhae-Masan Bay and adjacent areas, in April 1986 and in 1996. The PSP outbreaks were caused by the consumption of mussels, Mytilus edulis. The organism that caused PSP was identified, from morphological data only, as Alexandrium tamarense which is recently renamed as A. catenella, however recent studies have shown that the morphological diagnostic characteristics used to identify Alexandrium species have uncertainties and molecular tools and other criteria should be considered as well. The organism that caused past PSP outbreaks and incidents in Korea therefore need to be carefully reconsidered. The aim of this study was to re-evaluate the species really responsible for past outbreaks of PSP in Jinhae-Masan Bay, Korea. The temporal production and fluxes of the resting cysts of Alexandrium species were investigated for one year (from March 2011 to February 2012) using a sediment trap, and the morphology and phylogeny of vegetative cells germinated from the resting cysts were analysed. The production of Alexandrium species peaked in August and November, when temporal discrepancies were found in the water temperature (22.4 and 22.7°C in August, 19.1 and 19.6°C in November) and salinity (29.5 and 26.1 psu in August, 30.5 and 31.8 psu in November). The morphological data revealed that Alexandrium species germinated from resting cysts collected in August have a ventral pore on the 1' plate, whereas the 1' plate in Alexandrium species germinated from resting cysts collected in November lacks a ventral pore. Molecular phylogenetic data for the vegetative cells from the germination experiments allowed the August and November peaks to be assigned to Alexandrium catenella (Group I) and A. pacificum (Group IV), respectively. This indicates that the production of resting cysts of A. catenella can be enhanced by relatively high water temperature. This result is not consistent with those of previous studies that A. catenella responsible for PSP outbreaks was found at relatively low water temperature. In addition, large subunit ribosomal sequences data revealed that A. pacificum isolates from Korea were closely related to those from Australia, Japan and New Zealand where the PSP toxicity of shellfish and blooms occurred in the 1990s, indicating that the introduction of toxic dinoflagellates were related to ballast water from bulk-cargo shipping. Based on these results, we concluded that past PSP outbreaks in Jinhae-Masan Bay of Korea could have been caused by A. pacificum rather than by A. catenella.


Assuntos
Dinoflagelados/fisiologia , Surtos de Doenças , Paralisia/epidemiologia , Intoxicação por Frutos do Mar/epidemiologia , Dinoflagelados/ultraestrutura , Geografia , Humanos , Funções Verossimilhança , Filogenia , República da Coreia/epidemiologia , Estações do Ano , Especificidade da Espécie , Temperatura Ambiente
18.
Harmful Algae ; 68: 67-81, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28962991

RESUMO

Asexual and sexual life cycle events were studied in cultures of the toxic marine dinoflagellate Protoceratium reticulatum. Asexual division by desmoschisis was characterized morphologically and changes in DNA content were analyzed by flow cytometry. The results indicated that haploid cells with a C DNA content occurred only during the light period whereas a shift from a C to a 2C DNA content (indicative of S phase) took place only during darkness. The sexual life cycle was documented by examining the mating type as well as the morphology of the sexual stages and nuclei. Gamete fusion resulted in a planozygote with two longitudinal flagella, but longitudinally biflagellated cells arising from planozygote division were also observed, so one of the daughter cells retained two longitudinal flagella while the other daughter cell lacked them. Presumed planozygotes (identified by their longitudinally biflagellated form) followed two life-cycle routes: division and encystment (resting cyst formation). Both the division of longitudinally biflagellated cells and resting cyst formation are morphologically described herein. Resting cyst formation through sexual reproduction was observed in 6.1% of crosses and followed a complex heterothallic pattern. Clonal strains underwent sexuality (homothallism for planozygote formation and division) but without the production of resting cysts. Ornamental processes of resting cysts formed from the cyst wall under an outer balloon-shaped membrane and were fully developed in <1h. Obligatory dormancy period was of ∼4 months. Excystment resulted in a large, rounded, pigmented, longitudinally biflagellated but motionless, thecate germling that divided by desmoschisis. Like the planozygote, the first division of the germling yielded one longitudinally biflagellated daughter cell and another without longitudinal flagella. The longitudinal biflagellation state of both sexual stages and of the first division products of these cells is discussed.


Assuntos
Organismos Aquáticos/crescimento & desenvolvimento , Dinoflagelados/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Organismos Aquáticos/citologia , Organismos Aquáticos/isolamento & purificação , Organismos Aquáticos/ultraestrutura , Divisão Celular , Núcleo Celular/metabolismo , Dinoflagelados/citologia , Dinoflagelados/isolamento & purificação , Dinoflagelados/ultraestrutura , Cinética , Zigoto/citologia
19.
Protist ; 168(5): 586-611, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28987651

RESUMO

A gymnodinioid photosynthetic dinoflagellate was isolated from Argentina and examined by light and electron microscopy and analysis of nuclear-encoded LSU rDNA. Kirithra asteri gen. et sp. nov. was proposed as morphology and molecular phylogeny separated this dinoflagellate from others within the family Ceratoperidiniaceae. Cells were surrounded by a hyaline amphiesma comprising polygonal vesicles. Each vesicle contained a honeycomb and a trilaminar structure. An anterior sulcal extension ending in a complete circle formed the apical structure complex (ASC), which characterizes Ceratoperidiniaceae. The ASC comprised three rows of vesicles. The nucleus was located in the hypocone, and several large, irregularly shaped vesicles were present in the epi- and hypocone. Chloroplasts were surrounded by three membranes, and grana-like arrangements of thylakoids were observed in one strain used for ultrastructural study. The cell centre contained 1-3 multiple-stalked pyrenoids and membrane-bound vesicles containing tile-like structures surrounded each pyrenoid. Two pusules with collecting chambers and associated vesicles branched off each of the flagellar canals. The flagellar apparatus featured a ventral connective between the amphiesma and the R1 root, and almost opposite basal bodies, rarely seen in dinoflagellates. This was the first ultrastructural study of a species within Ceratoperidiniaceae.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/ultraestrutura , Filogenia , Argentina , Cloroplastos/ultraestrutura , DNA de Protozoário/genética , DNA Ribossômico/genética , Dinoflagelados/citologia , Dinoflagelados/genética , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Análise de Sequência de DNA , Especificidade da Espécie
20.
J Phycol ; 53(6): 1305-1324, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28915316

RESUMO

One of the most common marine dinophytes is a species known as Heterocapsa triquetra. When Stein introduced the taxon Heterocapsa, he formally based the type species H. triquetra on the basionym Glenodinium triquetrum. The latter was described by Ehrenberg and is most likely a species of Kryptoperidinium. In addition to that currently unresolved nomenclatural situation, the thecal plate composition of H. triquetra sensu Stein (1883) was controversial in the past. To clarify the debate, we collected material and established the strain UTKG7 from the Baltic Sea off Kiel (Germany, the same locality as Stein had studied), which was investigated using light and electron microscopy, and whose systematic position was inferred using molecular phylogenetics. The small motile cells (18-26 µm in length) had a biconical through fusiform shape and typically were characterized by a short asymmetrically shaped, horn-like protuberance at the antapex. A large spherical nucleus was located in the episome, whereas a single pyrenoid laid in the lower cingular plane. The predominant plate pattern was identified as apical pore complex (Po, cp?, X), 4', 2a, 6'', 6c, 5s, 5''', 2''''. The triradiate body scales were 254-306 nm in diameter, had 6 ridges radiating from a central spine, 9 peripheral and 3 radiating spines, and 12 peripheral bars as well as a central depression in the basal plate. Our work provides a clarification of morphological characters and a new, validly published name for this important but yet formally undescribed species of Heterocapsa: H. steinii sp. nov.


Assuntos
Dinoflagelados/citologia , Dinoflagelados/genética , Dinoflagelados/classificação , Dinoflagelados/ultraestrutura , Alemanha , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia , RNA de Protozoário/genética , RNA Ribossômico/genética , Análise de Sequência de DNA , Especificidade da Espécie
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