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1.
Sci Total Environ ; 689: 655-661, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31279212

RESUMO

Ostreopsis cf. ovata is a benthic microalga distributed in tropical and temperate regions worldwide which produces palytoxins (PlTXs). Herein, an electrochemical biosensor for the detection of this toxic microalga is described. The detection strategy involves isothermal recombinase polymerase amplification (RPA) of the target using tailed primers and a sandwich hybridisation assay on maleimide-coated magnetic beads immobilised on electrode arrays. The biosensor attained a limit of detection of 9 pg/µL of O. cf. ovata DNA (which corresponds to ~640 cells/L), with no interferences from two non-target Ostreopsis species (O. cf. siamensis and O. fattorussoi). The biosensor was applied to the analysis of planktonic and benthic environmental samples. Electrochemical O. cf. ovata DNA quantifications demonstrated an excellent correlation with other molecular methods (qPCR and colorimetric assays) and allowed the construction of a predictive regression model to estimate O. cf. ovata cell abundances. This new technology offer great potential to improve research, monitoring and management of O. cf. ovata and harmful algal blooms.


Assuntos
Técnicas Biossensoriais/métodos , DNA de Algas/análise , DNA de Protozoário/análise , Dinoflagelados/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Técnicas Biossensoriais/instrumentação , Proliferação Nociva de Algas
2.
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
3.
Harmful Algae ; 78: 86-94, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30196928

RESUMO

Recurrent green tides have been recorded in the Yellow Sea for 11 consecutive years. The origin of floating green algae in the Yellow Sea, however, remains a subject of debate. Previous studies suggest that the major bloom-forming green alga Ulva prolifera represent a unique ecotype different from other attached populations of U. prolifera in China. In this study, 97 green algal samples collected during the 2012 green-tide event and from other locations along the coastline of China were analyzed. Based on the sequences of nuclear ribosomal RNA gene (rDNA) internal transcribed spacer (ITS) region and 5S rDNA spacer region, the green alga U. prolifera in the samples were identified. The intraspecific genetic diversity within U. prolifera was then examined using sequences of 5S rDNA spacer and a marker of sequence characterized amplified region (SCAR) highly specific for bloom-forming U. prolifera in the Yellow Sea. The screening results for SCAR marker demonstrated that U. prolifera attached to aquaculture rafts in Subei Shoal belong to the same ecotype of the bloom-forming U. prolifera in the Yellow Sea. These findings offer genetic evidence that aquaculture rafts in Subei Shoal are a major source of floating green algae in the Yellow Sea.


Assuntos
Eutrofização/fisiologia , Variação Genética , Ulva/genética , Aquicultura , China , DNA de Algas/análise , DNA Ribossômico/análise , Marcadores Genéticos , Ulva/classificação
4.
J Phycol ; 54(6): 788-798, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30246453

RESUMO

This is the first report of a coralline genus with both geniculate (upright fronds with non-calcified joints) and nongeniculate species that has been verified by DNA sequence data. Two nongeniculate (crustose) species of Bossiella are recognized, B. mayae sp. nov. and B. exarticulata sp. nov. DNA sequencing of the lectotype specimen of Pseudolithophyllum whidbeyense revealed that this name had been misapplied and instead belongs to an undescribed coralline species in the Hapalidiales. Phylogenetic analyses of concatenated DNA sequences (psbA, rbcL, COI-5P) indicate that B. mayae and B. exarticulata represent phenotypic reversals from the geniculate character state back to the nongeniculate character state. Secondary loss of genicula has occurred three times in the subfamily Corallinoideae, once to generate the entirely nongeniculate genus Crusticorallina and twice in the now morphologically heterotypic Bossiella. Since phenotypic reversals have occurred several times during the evolution of coralline algae, we speculate about the putative mechanism and adaptive significance of this phenomenon.


Assuntos
Evolução Biológica , Rodófitas/anatomia & histologia , Rodófitas/genética , DNA de Algas/análise , Filogenia , Análise de Sequência de DNA
5.
Nat Commun ; 9(1): 3094, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-30082897

RESUMO

Red-snow algae are red-pigmented unicellular algae that appear seasonally on the surface of thawing snow worldwide. Here, we analyse the distribution patterns of snow algae sampled from glaciers and snow patches in the Arctic and Antarctica based on nuclear ITS2 sequences, which evolve rapidly. The number of phylotypes is limited in both polar regions, and most are specific to either the Arctic or Antarctica. However, the bipolar phylotypes account for the largest share (37.3%) of all sequences, suggesting that red-algal blooms in polar regions may comprise mainly cosmopolitan phylotypes but also include endemic organisms, which are distributed either in the Arctic or Antarctica.


Assuntos
DNA Intergênico/análise , Rodófitas/fisiologia , Estações do Ano , Regiões Antárticas , Regiões Árticas , DNA de Algas/análise , Eutrofização , Geografia , Camada de Gelo , Fotossíntese , Filogenia , RNA Ribossômico 18S/análise , Análise de Sequência de DNA , Neve
6.
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
7.
J Phycol ; 54(5): 616-629, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30076711

RESUMO

Lake Baikal, the oldest lake in the world, is home to spectacular biodiversity and extraordinary levels of endemism. While many of the animal species flocks from Lake Baikal are famous examples of evolutionary radiations, the lake also includes a wide diversity of endemic algae that are not well investigated with regards to molecular-biological taxonomy and phylogeny. The endemic taxa of the green algal order Cladophorales show a range of divergent morphologies that led to their classification in four genera in two families. We sequenced partial large- and small-subunit rDNA as well as the internal transcribed spacer region of 14 of the 16 described endemic taxa to clarify their phylogenetic relationships. One endemic morphospecies, Cladophora kusnetzowii, was shown to be conspecific with the widespread Aegagropila linnaei. All other endemic morphospecies formed a monophyletic group nested within the genus Rhizoclonium (Cladophoraceae), a very surprising result, in stark contrast to their morphological affinities. The Baikal clade represents a species flock of closely related taxa with very low genetic differentiation. Some of the morphospecies were congruent with lineages recovered in the phylogenies, but due to the low phylogenetic signal in the rDNA sequences the relationships within the Baikal clade were not all well resolved. The Baikal clade appears to represent a recent radiation, based on the low molecular divergence within the group, and it is hypothesized that the large morphological variation results from diversification in sympatry from a common ancestor in Lake Baikal.


Assuntos
Biodiversidade , Evolução Biológica , Clorófitas/classificação , Filogenia , Clorófitas/anatomia & histologia , Clorófitas/citologia , Clorófitas/genética , DNA de Algas/análise , DNA Ribossômico/análise , Evolução Molecular , Lagos , Análise de Sequência de DNA , Sibéria
8.
J Phycol ; 54(5): 665-680, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30043990

RESUMO

Twenty years ago an Arctic cryptophyte was isolated from Baffin Bay and given strain number CCMP2045. Here, it was described using morphology, water- and non-water soluble pigments and nuclear-encoded SSU rDNA. The influence of temperature, salinity, and light intensity on growth rates was also examined. Microscopy revealed typical cryptophyte features but the chloroplast color was either green or red depending on the light intensity provided. Phycoerythrin (Cr-PE 566) was only produced when cells were grown under low-light conditions (5 µmol photons · m-2  · s-1 ). Non-water-soluble pigments included chlorophyll a, c2 and five major carotenoids. Cells measured 8.2 × 5.1 µm and a tail-like appendage gave them a comma-shape. The nucleus was located posteriorly and a horseshoe-shaped chloroplast contained a single pyrenoid. Ejectosomes of two sizes and a nucleomorph anterior to the pyrenoid were discerned in TEM. SEM revealed a slightly elevated vestibular plate in the vestibulum. The inner periplast component consisted of slightly overlapping hexagonal plates arranged in 16-20 oblique rows. Antapical plates were smaller and their shape less profound. Temperature and salinity studies revealed CCMP2045 as stenothermal and euryhaline and growth was saturated between 5 and 20 µmol photons · m-2  · s-1 . The phylogeny based on SSU rDNA showed that CCMP2045 formed a distinct clade with CCMP2293 and Falcomonas sp. isolated from Spain. Combining pheno- and genotypic data, the Arctic cryptophyte could not be placed in an existing family and genus and therefore Baffinellaceae fam. nov. and Baffinella frigidus gen. et sp. nov. were proposed.


Assuntos
Criptófitas/classificação , Criptófitas/citologia , Baías , Criptófitas/química , Criptófitas/crescimento & desenvolvimento , DNA de Algas/análise , DNA Ribossômico/análise , Nunavut , Filogenia , Pigmentação
9.
J Phycol ; 54(5): 720-733, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30055054

RESUMO

Extremophilic microalgae are primary producers in acidic habitats, such as volcanic sites and acid mine drainages, and play a central role in biogeochemical cycles. Yet, basic knowledge about their species composition and community assembly is lacking. Here, we begin to fill this knowledge gap by performing the first large-scale survey of microalgal diversity in acidic geothermal sites across the West Pacific Island Chain. We collected 72 environmental samples in 12 geothermal sites, measured temperature and pH, and performed rbcL amplicon-based 454 pyrosequencing. Using these data, we estimated the diversity of microalgal species, and then examined the relative contribution of contemporary selection (i.e., local environmental variables) and dispersal limitation on the assembly of these communities. A species delimitation analysis uncovered seven major microalgae (four red, two green, and one diatom) and higher species diversity than previously appreciated. A distance-based redundancy analysis with variation partitioning revealed that dispersal limitation has a greater influence on the community assembly of microalgae than contemporary selection. Consistent with this finding, community similarity among the sampled sites decayed more quickly over geographical distance than differences in environmental factors. Our work paves the way for future studies to understand the ecology and biogeography of microalgae in extreme habitats.


Assuntos
Biodiversidade , Meio Ambiente , Extremófilos/fisiologia , Microalgas/fisiologia , DNA de Algas/análise , Geografia , Sequenciamento de Nucleotídeos em Larga Escala , Japão , Microalgas/genética , Filipinas , Análise de Sequência de DNA , Taiwan
10.
Harmful Algae ; 76: 80-95, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29887207

RESUMO

A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P. bucculenta F. Gai, C. K. Hedemand, N. Lundholm & Ø. Moestrup sp. nov. Molecular and morphological diversity of the Namibian Pseudo-nitzschia species is discussed. Most importantly, P. bucculenta is both morphologically and phylogenetically most similar to P. dolorosa differing mainly in valve width and densities of striae, poroids and band striae as well as by four hemi-compensatory base changes in the ITS2. Morphological and molecular differences among the strains of P. decipiens suggest a temperate and a warm water subdivision. The geographical and toxigenic characteristics of the identified Pseudo-nitzschia species are described and compared to previous studies. Initial tests of toxin production in all seven species revealed production of domoic acid (DA) in two species: one strain of P. australis (0.074 pg DA cell-1) and two strains of P. plurisecta (0.338 pg DA cell-1 and 0.385 pg DA cell-1).


Assuntos
Diatomáceas/classificação , DNA de Algas/análise , DNA Espaçador Ribossômico/análise , Diatomáceas/química , Diatomáceas/genética , Diatomáceas/ultraestrutura , Toxinas Marinhas , Microscopia Eletrônica de Transmissão , Namíbia
11.
J Phycol ; 54(4): 429-434, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29920669

RESUMO

An essential suite of coral reef ecosystem engineers is coralline red algae. Among these, the smooth, encrusting Porolithon onkodes has historically been considered the most important and common reef building species worldwide. We assess P. onkodes biodiversity by performing a genomic analysis of the lectotype specimen collected in 1892 from the Tami Islands, Gulf of Huon, east of New Guinea. Comparisons of DNA sequences from the lectotype specimen to those deposited in GenBank and to newly generated sequences from both field-collected and historical specimens demonstrate that at least 20 distinct species are passing under P. onkodes. We hypothesize that there were multiple evolutionary drivers including ecophysiology, hydrodynamic regimes, and biotic interactions as well as historical biogeography, which resulted in this high diversity of smooth, encrusting Porolithon species throughout the tropics. Our results emphasize the need to document the biodiversity, ecophysiology, and habitats of these tropical, reef-building algae in light of climate change and ocean acidification.


Assuntos
DNA de Algas/análise , Especiação Genética , Genoma de Planta , Rodófitas/classificação , Recifes de Corais , Filogenia , Dispersão Vegetal , Rodófitas/genética , Análise de Sequência de DNA
12.
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
13.
J Phycol ; 54(4): 539-549, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29846951

RESUMO

Phylogenetic clades based on DNA sequences such as the chloroplast rbcL gene and the nuclear ITS region are frequently used to delimit algal species. However, these molecular markers cannot accurately delimit boundaries among some Ulva species. Although Ulva reticulata and Ulva ohnoi occasionally bloom in tropical to warm-temperate regions and are clearly distinguishable by their reticulate or plain blade morphology, they have few or no sequence divergences in these molecular markers and form a monophyletic clade. In this study, to clarify the speciation and species delimitation in the U. reticulata-ohnoi complex clade, reproductive relationships among several sexual strains from the Philippines and Japan including offspring that originated from the type specimen of U. ohnoi were examined by culturing and hybridization in addition to the ITS-based analysis. As a result, both prezygotic and postzygotic reproductive isolation were revealed to occur between genetically perforated U. reticulata and imperforate U. ohnoi. They were also separated on the basis of sequence analysis of the ITS region. That strongly supports that the two taxa are independent biological species. Although no prezygotic barrier among the Philippine and Japanese strains of U. reticulata was observed, unexpectedly zoospores produced by hybrid sporophytes in some of their combinations mostly failed to develop, indicating partial formation of a postzygotic barrier despite a 0.2% divergence in the ITS sequence. These findings suggest speciation is still ongoing in U. reticulata.


Assuntos
Especiação Genética , Hibridização Genética , Isolamento Reprodutivo , Ulva/fisiologia , DNA de Algas/análise , DNA Intergênico/análise , Japão , Filipinas , Ulva/classificação , Ulva/genética
14.
J Phycol ; 54(3): 391-409, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29574890

RESUMO

A multi-gene (SSU, LSU, psbA, and COI) molecular phylogeny of the family Corallinaceae (excluding the subfamilies Lithophylloideae and Corallinoideae) showed a paraphyletic grouping of six monophyletic clades. Pneophyllum and Spongites were reassessed and recircumscribed using DNA sequence data integrated with morpho-anatomical comparisons of type material and recently collected specimens. We propose Chamberlainoideae subfam. nov., including the type genus Chamberlainium gen. nov., with C. tumidum comb. nov. as the generitype, and Pneophyllum. Chamberlainium is established to include several taxa previously ascribed to Spongites, the generitype of which currently resides in Neogoniolithoideae. Additionally we propose two new genera, Dawsoniolithon gen. nov. (Metagoniolithoideae), with D. conicum comb. nov. as the generitype and Parvicellularium gen. nov. (subfamily incertae sedis), with P. leonardi sp. nov. as the generitype. Chamberlainoideae has no diagnostic morpho-anatomical features that enable one to assign specimens to it without DNA sequence data, and it is the first subfamily to possess both Type 1 (Chamberlainium) and Type 2 (Pneophyllum) tetra/bisporangial conceptacle roof development. Two characters distinguish Chamberlainium from Spongites: tetra/biasporangial conceptacle chamber diameter (<300 µm in Chamberlainium vs. >300 µm in Spongites) and tetra/bisporangial conceptacle roof thickness (<8 cells in Chamberlainium vs. >8 cells in Spongites). Two characters also distinguish Pneophyllum from Dawsoniolithon: tetra/bisporangial conceptacle roof thickness (<8 cells in Pneophyllum vs. >8 cells in Dawsoniolithon) and thallus construction (dimerous in Pneophyllum vs. monomerous in Dawsoniolithon).


Assuntos
Filogenia , Rodófitas/classificação , DNA de Algas/análise , Oceano Índico , Oceano Pacífico , Rodófitas/genética , Análise de Sequência de DNA
15.
J Phycol ; 54(2): 275-298, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29419886

RESUMO

The diatom genus Entomoneis is known from the benthos and plankton of marine, brackish, and freshwaters. Entomoneis includes diatoms with a bilobate keel elevated above the valve surface, a sigmoid canal raphe, and numerous girdle bands. Owing mostly to the scarcity of molecular data for a diverse set of species, the phylogeny of Entomoneis has not been investigated in depth. The few previous studies that included Entomoneis were focused on broader questions and the available data were from a small number of either unidentified Entomoneis or well-known species (e.g., E. paludosa). Since the first description of new species combining both molecular and morphological characters (E. tenera), we have continued to cultivate and investigate Entomoneis in the plankton of the Adriatic Sea. Combined multigene phylogeny (SSU rDNA sequences, rbcL, and psbC genes) and morphological observations (LM, SEM and TEM) revealed six new Entomoneis species supported by phylogenetic and morphological data: E. pusilla, E. gracilis, E. vilicicii, E. infula, E. adriatica, and E. umbratica. The most important morphological features for species delineation were cell shape, the degree and mode of torsion, valve apices, the appearance and structure of the transition between keel and valve body, the ultrastructure and the shape of the girdle bands, and the arrangement and density of perforations along the valve and valvocopulae. Our results highlight the underappreciated diversity of Entomoneis and call for a more in-depth morphological and molecular investigation of this genus especially in planktonic habitats.


Assuntos
Diatomáceas/classificação , Diatomáceas/citologia , Proteínas de Algas/análise , Croácia , DNA de Algas/análise , DNA Ribossômico/análise , Diatomáceas/genética , Diatomáceas/ultraestrutura , Mar Mediterrâneo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia
16.
J Phycol ; 54(2): 159-170, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29344959

RESUMO

The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid "Chantransia" stage, a distinctive macroscopic gametophyte with multi-axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera, Thorea and Nemalionopsis. Thorea has been widely reported with numerous species, whereas Nemalionopsis has been more rarely observed with only a few species described. DNA sequences from three loci (rbcL, cox1, and LSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China, and India. Sixteen species of Thorea and two species of Nemalionopsis were recognized. Morphological observations confirmed the distinctness of the two genera and also provided some characters to distinguish species. However, many of the collections were in "Chantransia" stage rather than gametophyte stage, meaning that key diagnostic morphological characters were unavailable. Three new species are proposed primarily based on the DNA sequence data generated in this study, Thorea kokosinga-pueschelii, T. mauitukitukii, and T. quisqueyana. In addition to these newly described species, one DNA sequence from GenBank was not closely associated with other Thorea clades and may represent further diversity in the genus. Two species in Nemalionopsis are recognized, N. shawii and N. parkeri nom. et stat. nov. Thorea harbors more diversity than had been recognized by morphological data alone. Distribution data indicated that Nemalionopsis is common in the Pacific region, whereas Thorea is more globally distributed. Most species of Thorea have a regional distribution, but Thorea hispida appears to be cosmopolitan.


Assuntos
Proteínas de Algas/análise , DNA de Algas/análise , Rodófitas/classificação , Rodófitas/genética , Análise de Sequência de DNA
17.
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
18.
J Phycol ; 54(1): 105-113, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29120060

RESUMO

Although hypotheses have been proposed and developed to interpret the origins and functions of introns, substantial controversies remain about the mechanism of intron evolution. The availability of introns in the intermediate state is quite helpful for resolving this debate. In this study, a new strain of diatom (denominated as DB21-1) was isolated and identified as Olifantiella sp., which possesses multiple types of 18S rDNAs (obtained from genomic DNA; lengths ranged from 2,056 bp to 2,988 bp). Based on alignments between 18S rDNAs and 18S rRNA (obtained from cDNA; 1,783 bp), seven intron insertion sites (IISs) located in the 18S rDNA were identified, each of which displayed the polymorphism of intron presence/absence. Specific primers around each IIS were designed to amplify the introns and the results indicated that introns in the same IIS varied in lengths, while terminal sequences were conserved. Our study showed that the process of intron loss happens via a series of successive steps, and each step could derive corresponding introns under intermediate states. Moreover, these results indicate that the mechanism of genomic deletion that occurs at DNA level can also lead to exact intron loss.


Assuntos
Diatomáceas/genética , Íntrons/genética , Polimorfismo Genético , DNA de Algas/análise , Filogenia , RNA de Algas/análise , RNA Ribossômico 18S/análise , Alinhamento de Sequência
19.
J Eukaryot Microbiol ; 65(1): 38-47, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28508432

RESUMO

A complex of closely related Mallomonas taxa belonging to the section Papillosae, M. kalinae Rezácová and M. rasilis Dürrschmidt, has been studied in detail by molecular and morphometric methods. Our investigations uncovered the existence of a new species found in water bodies in Vietnam, which we describe here as Mallomonas furtiva sp. nov. This taxon is morphologically very similar to M. kalinae, from which it differs by minute, but statistically significant morphological differences on the structure of silica scales. Indeed, the principal component analysis of morphological traits measured on silica scales significantly separates all three species in the complex. Mallomonas kalinae and M. furtiva differ by number of papillae on the shield and the dome, as well as by the scale sizes. Likewise, Mallomonas rasilis and M. furtiva are primarily differentiated by the absence of submarginal anterior ribs on silica scales of the former species. Phylogenetic analyses showed that Mallomonas furtiva is closely related to M. kalinae, with which it formed a highly supported lineage. Distribution patterns of all three studied taxa are further discussed.


Assuntos
Microbiota , Estramenópilas/classificação , Proteínas de Algas/análise , DNA de Algas/análise , DNA Ribossômico/análise , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia , Estramenópilas/genética , Estramenópilas/ultraestrutura , Vietnã , Áreas Alagadas
20.
J Phycol ; 54(1): 79-84, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29083489

RESUMO

A new genus, Ottia, and family, Ottiaceae, are proposed within the Acrochaetiales to accommodate the uniseriate red algal endophyte of batrachspermalean taxa previously named Balbiania meiospora. Prior to this study, Balbiania investiens was transferred to its own family and order (Balbianiales) based on comparative DNA sequence data and a distinctive reproductive morphology. However, the second species described in this genus, B. meiospora, continued to be treated as a species of Audouinella (A. meiospora) pending further investigation. Phylogenetic analyses of sequence data confirmed only a distant relationship between the two endophytes, and a closer alliance of B. meiospora to Acrochaetiales. The data also showed that Ottia meiospora was the deepest diverging lineage in the Acrochaetiales, sister to all of the currently recognized genera and families. In this study, we review the classification of what we now call O. meiospora - reported from Australia, New Zealand and Brazil - based on sequence and morphological data. Morphological observations provided little clarity around the reproductive morphology or the life cycle of this endophyte of Nothocladus s. lat. found commonly in mainland Australia but, to date, less so in New Zealand.


Assuntos
Rodófitas/classificação , Rodófitas/fisiologia , Austrália , Brasil , DNA de Algas/análise , Endófitos/classificação , Endófitos/fisiologia , Nova Zelândia , Filogenia , Análise de Sequência de DNA
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