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1.
Protist ; 171(4): 125741, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32593858

RESUMO

Phytodinialean dinophytes are poorly known at present and their phylogenetic relationships largely elusive. Historical names of microscopic species are frequently ambiguous, and a reliable application is impeded although crucial to fully explore the biology of organisms. We collected material close to the type locality of a historical species, namely Dinastridium verrucosum, and established eight strains for morphological and molecular studies. The motile cells showed an obovate shape in outline and were dorso-ventrally slightly flattened. They were orange-brown in colour and had a descending cingulum. In light microscopy, an eyespot was discerned in a few monadoid cells in the central region of the sulcus. Furthermore, a morphologically characteristic, 4-6µm long apical furrow was observed on the episome of the cells in SEM. Older cultivated material further exhibited coccoid cells of irregular shape, with wart-like protuberances and covered by a more or less extensive mucilage. This morphology is indistinguishable from the lectotype of D. verrucosum. In a molecular phylogeny, the species was placed in the Borghiellaceae (†Suessiales). As taxonomic result, we epitypify the historical name, D. verrucosum, and perform the necessary combination to Borghiella.


Assuntos
Dinoflagelados/classificação , Filogenia , DNA de Protozoário/genética , Dinoflagelados/genética , Dinoflagelados/ultraestrutura , Alemanha , Microscopia Eletrônica de Varredura , Especificidade da Espécie
2.
PLoS One ; 15(4): e0231400, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32294110

RESUMO

Marine dinoflagellates produce a diversity of polyketide toxins that are accumulated in marine food webs and are responsible for a variety of seafood poisonings. Reef-associated dinoflagellates of the genus Gambierdiscus produce toxins responsible for ciguatera poisoning (CP), which causes over 50,000 cases of illness annually worldwide. The biosynthetic machinery for dinoflagellate polyketides remains poorly understood. Recent transcriptomic and genomic sequencing projects have revealed the presence of Type I modular polyketide synthases in dinoflagellates, as well as a plethora of single domain transcripts with Type I sequence homology. The current transcriptome analysis compares polyketide synthase (PKS) gene transcripts expressed in two species of Gambierdiscus from French Polynesia: a highly toxic ciguatoxin producer, G. polynesiensis, versus a non-ciguatoxic species G. pacificus, each assembled from approximately 180 million Illumina 125 nt reads using Trinity, and compares their PKS content with previously published data from other Gambierdiscus species and more distantly related dinoflagellates. Both modular and single-domain PKS transcripts were present. Single domain ß-ketoacyl synthase (KS) transcripts were highly amplified in both species (98 in G. polynesiensis, 99 in G. pacificus), with smaller numbers of standalone acyl transferase (AT), ketoacyl reductase (KR), dehydratase (DH), enoyl reductase (ER), and thioesterase (TE) domains. G. polynesiensis expressed both a larger number of multidomain PKSs, and larger numbers of modules per transcript, than the non-ciguatoxic G. pacificus. The largest PKS transcript in G. polynesiensis encoded a 10,516 aa, 7 module protein, predicted to synthesize part of the polyether backbone. Transcripts and gene models representing portions of this PKS are present in other species, suggesting that its function may be performed in those species by multiple interacting proteins. This study contributes to the building consensus that dinoflagellates utilize a combination of Type I modular and single domain PKS proteins, in an as yet undefined manner, to synthesize polyketides.


Assuntos
Dinoflagelados/enzimologia , Policetídeo Sintases/genética , Transcriptoma , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Ciguatoxinas/metabolismo , Dinoflagelados/classificação , Dinoflagelados/isolamento & purificação , Perfilação da Expressão Gênica/métodos , Biblioteca Gênica , Filogenia , Policetídeo Sintases/metabolismo , Polinésia , RNA/química , RNA/isolamento & purificação , RNA/metabolismo
3.
Proc Natl Acad Sci U S A ; 117(10): 5364-5375, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32094181

RESUMO

Nucleomorphs are relic endosymbiont nuclei so far found only in two algal groups, cryptophytes and chlorarachniophytes, which have been studied to model the evolutionary process of integrating an endosymbiont alga into a host-governed plastid (organellogenesis). However, past studies suggest that DNA transfer from the endosymbiont to host nuclei had already ceased in both cryptophytes and chlorarachniophytes, implying that the organellogenesis at the genetic level has been completed in the two systems. Moreover, we have yet to pinpoint the closest free-living relative of the endosymbiotic alga engulfed by the ancestral chlorarachniophyte or cryptophyte, making it difficult to infer how organellogenesis altered the endosymbiont genome. To counter the above issues, we need novel nucleomorph-bearing algae, in which endosymbiont-to-host DNA transfer is on-going and for which endosymbiont/plastid origins can be inferred at a fine taxonomic scale. Here, we report two previously undescribed dinoflagellates, strains MGD and TGD, with green algal endosymbionts enclosing plastids as well as relic nuclei (nucleomorphs). We provide evidence for the presence of DNA in the two nucleomorphs and the transfer of endosymbiont genes to the host (dinoflagellate) genomes. Furthermore, DNA transfer between the host and endosymbiont nuclei was found to be in progress in both the MGD and TGD systems. Phylogenetic analyses successfully resolved the origins of the endosymbionts at the genus level. With the combined evidence, we conclude that the host-endosymbiont integration in MGD/TGD is less advanced than that in cryptophytes/chrorarachniophytes, and propose the two dinoflagellates as models for elucidating organellogenesis.


Assuntos
Cercozoários/ultraestrutura , Criptófitas/ultraestrutura , Dinoflagelados/ultraestrutura , Evolução Molecular , Genomas de Plastídeos , Plastídeos/fisiologia , Simbiose , Núcleo Celular/genética , Núcleo Celular/fisiologia , Cercozoários/classificação , Cercozoários/genética , Clorófitas/classificação , Clorófitas/fisiologia , Clorófitas/ultraestrutura , Criptófitas/classificação , Criptófitas/genética , Dinoflagelados/classificação , Dinoflagelados/genética , Modelos Biológicos , Filogenia , Plastídeos/genética
4.
Protist ; 171(1): 125700, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31877469

RESUMO

Parvodinium elpatiewskyi, comb. nov., is a common freshwater dinophyte without intercalary plates and with various spines on hypothecal sutures. However, the taxonomy of the species has had a complex history, and its systematic placement remained unclear. The conserved type of P. elpatiewskyi, comb. nov., illustrated here for the first time using electron microscopy, is an environmental sample. Based on the newly collected material from Berlin (Germany) we provide a morphological description using light and electron microscopy as well as new molecular rRNA sequence data to specify the phylogenetic position of P. elpatiewskyi, comb. nov. This species belongs to Peridiniopsidaceae, more precisely to Parvodinium, which usually possesses two intercalary plates. However, evolutionary inference indicates the loss of such plates in P. elpatiewskyi, comb. nov. Other traits that are of taxonomic importance and have not received enough attention in the past are the large Sd plate converging the second antapical plate and the presence of cellular hypocystal opening during replication.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/ultraestrutura , Filogenia , Dinoflagelados/genética , Água Doce , Alemanha , RNA Ribossômico/genética , Especificidade da Espécie
5.
Protist ; 170(6): 125699, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31770639

RESUMO

Ciguatera fish poisoning (CFP) is a human illness caused via consumption of seafood contaminated with neurotoxins produced by some species from the epiphytic dinoflagellate genus Gambierdiscus. In this study, we describe two new species of Gambierdiscus isolated from Heron Island in the Southern Great Barrier Reef, Queensland, Australia. These new species were analysed using light microscopy, scanning electron microscopy, and phylogenetic analyses of nuclear encoded ribosomal ITS, SSU as well as D1-D3 and D8-D10 of the LSU gene regions. Gambierdiscus lewisii sp. nov. (Po, 3', 0a, 7″, 6c,? s, 5‴, 0p, 2'‴) is distinguished by its strong reticulate-foveate ornamentation and is genetically distinct from its sister species, G. pacificus. Gambierdiscus holmesii sp. nov. (Po, 3', 0a, 7″, 6c, 6s?, 5‴, 0p, 2'‴) is morphologically distinct from the genetically similar species G. silvae because of a strongly ventrally displaced apical pore complex and a characteristic fold at the anterior edge of the sulcus. Both G. lewisii and G. holmesii produce putative Maitotoxin-(44-Methylgambierone) and compounds which show ciguatoxin and maitotoxin-like activities. Identification of two new Gambierdiscus species will enable us to more accurately assess the risk of CFP in Australia and internationally.


Assuntos
Dinoflagelados/classificação , Filogenia , Austrália , DNA de Protozoário/genética , Dinoflagelados/genética , Dinoflagelados/ultraestrutura , Toxinas Marinhas/genética , Microscopia Eletrônica de Varredura , Oxocinas , Oceano Pacífico
6.
Parasit Vectors ; 12(1): 472, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604479

RESUMO

BACKGROUND: The parasitic dinoflagellates of the genus Hematodinium represent the causative agent of so-called bitter or pink crab disease in a broad range of shellfish taxa. Outbreaks of Hematodinium-associated disease can devastate local fishing and aquaculture efforts. The goal of our study was to examine the potential role of the common shore (green) crab Carcinus maenas as a reservoir for Hematodinium. Carcinus maenas is native to all shores of the UK and Ireland and the North East Atlantic but has been introduced to, and subsequently invaded waters of, the USA, South Africa and Australia. This species is notable for its capacity to harbour a range of micro- and macro-parasites, and therefore may act as a vector for disease transfer. METHODS: Over a 12-month period, we interrogated 1191 crabs across two distinct locations (intertidal pier, semi-closed dock) in Swansea Bay (Wales, UK) for the presence and severity of Hematodinium in the haemolymph, gills, hepatopancreas and surrounding waters (eDNA) using PCR-based methods, haemolymph preparations and histopathology. RESULTS: Overall, 13.6% were Hematodinium-positive via PCR and confirmed via tissue examination. Only a small difference was observed between locations with 14.4% and 12.8% infected crabs in the Dock and Pier, respectively. Binomial logistic regression models revealed seasonality (P < 0.002) and sex (P < 0.001) to be significant factors in Hematodinium detection with peak infection recorded in spring (March to May). Male crabs overall were more likely to be infected. Phylogenetic analyses of the partial ITS and 18S rRNA gene regions of Hematodinium amplified from crabs determined the causative agent to be the host generalist Hematodinium sp., which blights several valuable crustaceans in the UK alone, including edible crabs (Cancer pagurus) and langoustines (Nephrops norvegicus). CONCLUSIONS: Shore crabs were infected with the host generalist parasite Hematodinium sp. in each location tested, thereby enabling the parasite to persist in an environment shared with commercially important shellfish.


Assuntos
Alveolados/patogenicidade , Braquiúros/parasitologia , Reservatórios de Doenças/parasitologia , Alveolados/classificação , Alveolados/genética , Alveolados/fisiologia , Animais , Distribuição Binomial , DNA Espaçador Ribossômico/genética , Dinoflagelados/classificação , Dinoflagelados/genética , Dinoflagelados/patogenicidade , Dinoflagelados/fisiologia , Feminino , Brânquias/parasitologia , Hemolinfa/química , Hemolinfa/parasitologia , Modelos Logísticos , Masculino , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 18S/análise , Estações do Ano , Água do Mar/parasitologia , País de Gales
7.
Mar Pollut Bull ; 145: 105-117, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590766

RESUMO

The Beagle Channel is a remote subantarctic environment where mussel aquaculture initiatives have existed since the early 1990s. Here we analyze phytoplankton biomass and composition, and the occurrence of harmful microalgae species and their toxins at three sites during the period 2015-2016. The occurrence of potentially harmful algae was observed throughout the study period, including toxigenic dinoflagellates such as Alexandrium catenella (Group I of the A. tamarense complex), A. ostenfeldii, Dinophysis acuminata, Gonyaulax spinifera, Azadinium sp., and the diatoms Pseudo-nitzschia australis and P. fraudulenta. Toxic dinoflagellates were detected in low densities whereas a Pseudo-nitzschia bloom was observed in late February. Isolates of A. catenella and P. delicatissima sensu stricto were phylogenetically characterized. The toxin profile of A. catenella was dominated by GTX4, while P. delicatissima sensu stricto showed no production of the neurotoxin domoic acid in culture conditions. The results provide base-line information for the management of harmful algal blooms in this little explored subantarctic area.


Assuntos
Aquicultura , Diatomáceas/química , Dinoflagelados/química , Toxinas Marinhas/análise , Fitoplâncton/química , Animais , Biomassa , Diatomáceas/classificação , Diatomáceas/crescimento & desenvolvimento , Dinoflagelados/classificação , Dinoflagelados/crescimento & desenvolvimento , Proliferação Nociva de Algas , Microalgas/química , Microalgas/classificação , Microalgas/crescimento & desenvolvimento , Fitoplâncton/classificação , Fitoplâncton/crescimento & desenvolvimento , América do Sul
8.
Eur J Protistol ; 71: 125636, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31585232

RESUMO

The parasitic dinoflagellate Syltodinium listii was investigated from the open waters of the English Channel, southern North Sea and the NW Mediterranean Sea. Syltodinium listii has been unreported since its original description in the North Sea. Cells of S. listii were able to infect copepod eggs of different species, and even nauplii, and after each infection formed up to 32 cells embedded in a mucous envelope. Infection of the same host by more than one dinoflagellate was frequent; although overall, the progeny were reduced in number. Molecular phylogeny based on the small subunit ribosomal RNA (SSU rRNA) gene revealed that S. listii clusters with a group of environmental sequences from the cold North Atlantic region as a sister group of Gymnodinium aureolum. The large subunit ribosomal RNA (LSU rRNA) gene sequences of S. listii from the English Channel and cf. Gyrodinium undulans from the Mediterranean Sea were identical. Thus, we propose Syltodinium undulans comb. nov. for Gyrodinium undulans. The first internal transcribed spacer (ITS) and complete SSU rRNA gene sequences of Dissodinium pseudolunula are provided. The parasitic species of Chytriodinium, Dissodinium and Syltodinium cluster together within the family Chytriodiniaceae, including the free-living species Gymnodinium aureolum, G. corollarium and G. plasticum.


Assuntos
Dinoflagelados/classificação , Filogenia , DNA de Protozoário/genética , Dinoflagelados/genética , Mar Mediterrâneo , RNA Ribossômico 18S/genética , Especificidade da Espécie
9.
Environ Monit Assess ; 191(10): 603, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31482206

RESUMO

The spatial and temporal variation of phytoplankton communities including HAB species in relation to the environmental characteristics was investigated in the protected meso-oligotrophic Mellah lagoon located in the South Western Mediterranean. During 2016, a biweekly monitoring of phytoplankton assemblages and the main abiotic factors were realized at three representative stations. Taxonomic composition, abundance, and diversity index were determined. In total, 227 phytoplankton species (160 diatoms and 53 dinoflagellates) were inventoried. There was a clear dominance of diatoms (62.9%) compared with dinoflagellates (36.8%). Diatoms dominated in spring and dinoflagellates developed in summer and early autumn in Mellah showing a marked seasonal trend. Data showed that the dynamic of the phytoplankton taxa evolving in the lagoon was mainly driven by temperature and salinity. For the first time, a number of potentially toxic species have been identified, including 2 diatoms (Pseudo-nitzschia group delicatissima, Pseudo-nitzschia group seriata) and 5 dinoflagellates (Alexandrium minutum, Alexandrium tamarense/catenella, Dinophysis acuminata, Dinophysis sacculus, Prorocentrum lima). These harmful species could threat the functioning of the Mellah lagoon and human health and require the establishment of a monitoring network. Finally, our study suggests that the observed decrease of the phytoplankton diversity between 2001 and 2016 could result from the reduction in water exchanges between the lagoon and the adjacent coast following the gradual clogging of the channel.


Assuntos
Meio Ambiente , Monitoramento Ambiental , Fitoplâncton/classificação , Estações do Ano , Argélia , Diatomáceas/classificação , Diatomáceas/fisiologia , Dinoflagelados/classificação , Dinoflagelados/fisiologia , Fitoplâncton/fisiologia , Salinidade , Temperatura
10.
Eur J Protistol ; 71: 125638, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31550628

RESUMO

Pseudothecadinium campbellii, a phototrophic, thecate, marine benthic species, has been found in the Sea of Japan, Russia. The morphological description of the species has been emended, and the thecal tabulation pattern is now APC 4' 2a 4″ 6c 6 s 5‴ 1⁗. Our study indicates that P. campbellii is related to Thecadinium kofoidii and Thecadiniopsis tasmanica, based on a unique morphological feature: incomplete precingular plate series. Previously, molecular data was not available for the taxa, and thus the phylogenetic position of P. campbellii within the Dinophyceae remained obscure. In this study, analyses of the rRNA gene sequences (partial 18S and 28S) revealed that unexpectedly, P. campbellii is most closely related to Halostylodinium arenarium. It formed a common clade with the Thecadinium sensu stricto clade comprising T. kofoidii and T. pseudokofoidii. This clade was placed within the order Gonyaulacales. However, almost no similarity in morphology was found between the two genetically closest species. In addition, they have different lifestyles: unlike P. campbellii, the nonmotile stage is dominant in the life cycle of H. arenarium. It has been shown that other genetically similar species (T. kofoidii, T. pseudokofoidii, T. yashimaense) exhibited some morphological features that unite them with gonyaulacoids.


Assuntos
Dinoflagelados/classificação , Filogenia , DNA Ribossômico/genética , Dinoflagelados/citologia , Dinoflagelados/genética , Federação Russa , Especificidade da Espécie
11.
Protist ; 170(5): 125680, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31563792

RESUMO

Marine unarmored dinoflagellates in the family Kareniaceae are known to possess chloroplasts of haptophyte origin, which contain fucoxanthin and its derivatives as major carotenoids, and lack peridinin. In the present study, the first species with the peridinin-type chloroplast in this family, Gertia stigmatica gen. et sp. nov., is described on the basis of ultrastructure, photosynthetic pigment composition, and molecular phylogeny inferred from nucleus- and chloroplast-encoded genes. Cells of G. stigmatica were small and harboring a chloroplast with an eyespot and two pyrenoids. The apical structure complex was straight, similar to Karenia and Karlodinium. Under transmission electron microscopy, the chloroplast was surrounded by two membranes, and the eyespot was composed of a single layer of osmiophilic globules (eyespot type A); this was never previously reported from the Kareniaceae. High performance liquid chromatography demonstrated the chloroplast contains peridinin, and neither fucoxanthin nor 19'-acyloxyfucoxanthins was identified. A phylogeny based on nucleus-encoded rDNAs suggested a position of G. stigmatica in the Kareniaceae, but not clustered within the previously described genera, i.e., Karenia, Karlodinium and Takayama. A phylogeny of chloroplast-encoded psbA, psbC and psbD indicated the chloroplast is of peridinin-type typical of dinoflagellates, but the most related species remains unclear.


Assuntos
Organismos Aquáticos , Carotenoides , Cloroplastos , Dinoflagelados/classificação , Organismos Aquáticos/classificação , Organismos Aquáticos/citologia , Organismos Aquáticos/metabolismo , Carotenoides/metabolismo , Cloroplastos/classificação , Cloroplastos/metabolismo , Dinoflagelados/citologia , Dinoflagelados/metabolismo , Especificidade da Espécie
12.
Environ Microbiol ; 21(11): 4196-4211, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31415128

RESUMO

In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth. Their ecological success may be related to their production of complex toxic polyketide compounds. Ostreopsis species produce potent palytoxin-like compounds (PLTX), which are associated with human skin and eye irritations, and illnesses through the consumption of contaminated seafood. To investigate the genetic basis of PLTX-like compounds, we sequenced and annotated transcriptomes from two PLTX-producing Ostreopsis species; O. cf. ovata, O. cf. siamensis, one non-PLTX producing species, O. rhodesae and compared them to a close phylogenetic relative and non-PLTX producer, Coolia malayensis. We found no clear differences in the presence or diversity of ketosynthase and ketoreductase transcripts between PLTX producing and non-producing Ostreopsis and Coolia species, as both groups contained >90 and > 10 phylogenetically diverse ketosynthase and ketoreductase transcripts, respectively. We report for the first-time type I single-, multi-domain polyketide synthases (PKSs) and hybrid non-ribosomal peptide synthase/PKS transcripts from all species. The long multi-modular PKSs were insufficient by themselves to synthesize the large complex polyether backbone of PLTX-like compounds. This implies that numerous PKS domains, including both single and multi-, work together on the biosynthesis of PLTX-like and other related polyketide compounds.


Assuntos
Dinoflagelados/genética , Toxinas Marinhas/genética , Transcriptoma , Dinoflagelados/classificação , Humanos , Toxinas Marinhas/biossíntese , Oxirredutases/genética , Filogenia , Policetídeo Sintases/genética , Policetídeos/química , Metabolismo Secundário
13.
Protist ; 170(4): 358-373, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31415953

RESUMO

The plastid genomes of peridinin-containing dinoflagellates are highly unusual, possessing very few genes, which are located on small chromosomal elements termed "minicircles". These minicircles may contain genes, or no recognisable coding information. Transcripts produced from minicircles may undergo unusual processing events, such as the addition of a 3' poly(U) tail. To date, little is known about the genetic or transcriptional diversity of non-coding sequences in peridinin dinoflagellate plastids. These sequences include empty minicircles, and regions of non-coding DNA in coding minicircles. Here, we present an integrated plastid genome and transcriptome for the model peridinin dinoflagellate Amphidinium carterae, identifying a previously undescribed minicircle. We also profile transcripts covering non-coding regions of the psbA and petB/atpA minicircles. We present evidence that antisense transcripts are produced within the A. carterae plastid, but show that these transcripts undergo different end cleavage events from sense transcripts, and do not receive 3' poly(U) tails. The difference in processing events between sense and antisense transcripts may enable the removal of non-coding transcripts from peridinin dinoflagellate plastid transcript pools.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/genética , Genoma de Protozoário/genética , Plastídeos/genética , Transcriptoma/genética , Perfilação da Expressão Gênica , Genômica
14.
Environ Microbiol ; 21(11): 4125-4135, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31369197

RESUMO

Dinophytes are one of few protist groups that have an extensive fossil record and are therefore appropriate for time estimations. However, insufficient sequence data and strong rate heterogeneity have been hindering to put dinophyte evolution into a time frame until now. Marine-to-freshwater transitions within this group are considered geologically old and evolutionarily exceptional due to strong physiological constraints that prevent such processes. Phylogenies based on concatenated rRNA sequences (including 19 new GenBank entries) of two major dinophyte lineages, Gymnodiniaceae and Peridiniales, were carried out using an uncorrelated molecular clock and five calibration points based on fossils. Contrarily to previous assumptions, marine-to-freshwater transitions are more frequent in dinophytes (i.e. five marine-freshwater transitions in Gymnodiniaceae, up to ten but seven strongly supported transitions in Peridiniales), and none of them occurred as early as 140 MYA. Furthermore, most marine-to-freshwater transitions, and the followed diversification, took place after the Cretaceous-Paleogene boundary. Not older than 40 MYA, the youngest transitions within Gymnodiniaceae and Peridiniales occurred under the influence of the Eocene climate shift. Our evolutionary scenario indicates a gradual diversification of dinophytes without noticeable impact of catastrophic events, and their freshwater lineages have originated several times independently at different points in time.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/genética , Filogenia , Clima , Evolução Molecular , Fósseis , Água Doce , RNA Ribossômico/genética , Tempo
15.
Mol Ecol ; 28(16): 3830-3843, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31329312

RESUMO

The bacterial and microalgal endosymbiont (Symbiodiniaceae spp.) communities associated with corals have important roles in their health and resilience, yet little is known about the factors driving their succession during early coral life stages. Using 16S rRNA gene and ITS2 metabarcoding, we compared these communities in four Acropora coral species and their hybrids obtained from two laboratory crosses (Acropora tenuis × Acropora loripes and Acropora sarmentosa × Acropora florida) across the parental, recruit (7 months old) and juvenile (2 years old) life stages. We tested whether microbiomes differed between (a) life stages, (b) hybrids and purebreds, and (c) treatment conditions (ambient/elevated temperature and pCO2 ). Microbial communities of early life stage corals were highly diverse, lacked host specificity and were primarily determined by treatment conditions. Over time, a winnowing process occurred, and distinct microbial communities developed between the two species pair crosses by 2 years of age, irrespective of hybrid or purebred status. These findings suggest that the microbial communities of corals have a period of flexibility prior to adulthood, which can be valuable to future research aimed at the manipulation of coral microbial communities.


Assuntos
Antozoários/microbiologia , Bactérias/classificação , Dinoflagelados/classificação , Microbiota , Simbiose , Animais , Austrália , Código de Barras de DNA Taxonômico , Hibridização Genética , Estágios do Ciclo de Vida , RNA Ribossômico 16S/genética , Especificidade da Espécie
16.
Mar Pollut Bull ; 141: 629-648, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955778

RESUMO

The diversity of free-living dinoflagellates in the coastal areas of the central Red Sea, Saudi Arabia, was studied from April 2016 to March 2017. A total of 106 dinoflagellates belonging to 36 genera, 20 families and 7 orders were identified and characterized using light microscopy. Of these, 47 taxa were potentially harmful, and 60 taxa were recorded for the first time from the Red Sea. The unexpectedly high species diversity, including new records, was due to the benthic species. The monthly variability of planktonic species records exhibited negative correlations with temperature and salinity, although in most cases, the links between them were insignificant. Subsequently, the dinoflagellates checklist for the entire Red Sea was updated and showed that there were currently 395 taxa and 66 genera. The results of this study provide a solid foundation for future studies of dinoflagellate biodiversity in the Red Sea, particularly for benthic and harmful species.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/fisiologia , Biodiversidade , Oceano Índico , Salinidade , Arábia Saudita , Temperatura
17.
Mar Pollut Bull ; 147: 185-208, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30926267

RESUMO

The ability of microalgae to preserve viable in coastal sediments as resting forms provides a reservoir of biodiversity and a useful tool to determine species spreadings. This study represents the first port baseline survey on dinoflagellate cysts, investigated in nine Adriatic ports during a cross border project. 40 dinoflagellate taxa were detected. The assemblages resulted in all ports dominated by Lingulodinium polyedra and Alexandrium minutum/affine/tamutum group. General separation to the western and eastern side of the Adriatic regarding cysts assemblage composition, partially abundance, was observed. Six taxa were detected as non-indigenous species for the Adriatic. Two taxa are included in the list of harmful aquatic organisms, indicating the potential threat of ballast waters in the Adriatic. Potential spreading of taxa by general circulation and ballast waters, intra- and extra-Adriatic was investigated. The entering in to force of the ballast waters management regulations should enhance prospects to minimize future harmful impacts.


Assuntos
Dinoflagelados/fisiologia , Sedimentos Geológicos , Biodiversidade , Monitoramento Biológico/métodos , Croácia , Dinoflagelados/classificação , Espécies Introduzidas , Itália , Mar Mediterrâneo , Microalgas , Estações do Ano , Navios , Eslovênia , Inquéritos e Questionários , Instalações de Transporte
18.
Mol Ecol Resour ; 19(4): 1063-1080, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30740899

RESUMO

We present SymPortal (SymPortal.org), a novel analytical framework and platform for genetically resolving the algal symbionts of reef corals using next-generation sequencing (NGS) data of the ITS2 rDNA. Although the ITS2 marker is widely used to genetically characterize taxa within the family Symbiodiniaceae (formerly the genus Symbiodinium), the multicopy nature of the marker complicates its use. Commonly, the intragenomic diversity resultant from this multicopy nature is collapsed by analytical approaches, thereby focusing on only the most abundant sequences. In contrast, SymPortal employs logic to identify within-sample informative intragenomic sequences, which we have termed 'defining intragenomic variants' (DIVs), to identify ITS2-type profiles representative of putative Symbiodiniaceae taxa. By making use of this intragenomic ITS2 diversity, SymPortal is able to resolve genetic delineations using the ITS2 marker at a level that was previously only possible by using additional genetic markers. We demonstrate this by comparing this novel approach to the most commonly used alternative approach for NGS ITS2 data, the 97% similarity clustering to operational taxonomic units (OTUs). The SymPortal platform accepts NGS raw sequencing data as input to provide an easy-to-use, standardization-enforced, and community-driven framework that integrates with a database to gain resolving power with increased use. We consider that SymPortal, in conjunction with ongoing large-scale sampling and sequencing efforts, should play an instrumental role in making future sampling efforts more comparable and in maximizing their efficacy in working towards the classification of the global Symbiodiniaceae diversity.


Assuntos
Antozoários/parasitologia , Biologia Computacional/métodos , DNA de Protozoário/genética , DNA Espaçador Ribossômico/genética , Dinoflagelados/classificação , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Filogenia , Animais , DNA de Protozoário/química , DNA Espaçador Ribossômico/química , Dinoflagelados/genética , Dinoflagelados/isolamento & purificação
19.
ISME J ; 13(6): 1635-1638, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30705413

RESUMO

The establishment of coral microbial communities in early developmental stages is fundamental to coral fitness, but its drivers are largely unknown, particularly for bacteria. Using an in situ reciprocal transplant experiment, we examined the influence of parental, planulation and early recruit environments on the microbiome of brooded offspring in the coral Pocillopora damicornis. 16S rRNA and ITS2 rDNA gene metabarcoding showed that bacterial and microalgal endosymbiont communities varied according to parental and planulation environments, but not with early recruit environment. Only a small number of bacterial strains were shared between offspring and their respective parents, revealing bacterial establishment as largely environmentally driven in very early life stages. Conversely, microalgal communities of recruits were highly similar to those of their respective parents, but also contained additional low abundance strains, suggesting both vertical transmission and novel ('horizontal') acquisition. Altogether, recruits harboured more variable microbiomes compared to their parents, indicating winnowing occurs as corals mature.


Assuntos
Antozoários/crescimento & desenvolvimento , Antozoários/microbiologia , Bactérias/isolamento & purificação , Dinoflagelados/isolamento & purificação , Animais , Antozoários/parasitologia , Antozoários/fisiologia , Bactérias/classificação , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Dinoflagelados/classificação , Dinoflagelados/genética , Microbiota , Simbiose
20.
Proc Natl Acad Sci U S A ; 116(6): 2118-2123, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30670646

RESUMO

Reef-building corals thrive in nutrient-poor marine environments because of an obligate symbiosis with photosynthetic dinoflagellates of the genus Symbiodinium Symbiosis is established in most corals through the uptake of Symbiodinium from the environment. Corals are sessile for most of their life history, whereas free-living Symbiodinium are motile; hence, a mechanism to attract Symbiodinium would greatly increase the probability of encounter between host and symbiont. Here, we examined whether corals can attract free-living motile Symbiodinium by their green fluorescence, emitted by the excitation of endogenous GFP by purple-blue light. We found that Symbiodinium have positive and negative phototaxis toward weak green and strong purple-blue light, respectively. Under light conditions that cause corals to emit green fluorescence, (e.g., strong blue light), Symbiodinium were attracted toward live coral fragments. Symbiodinium were also attracted toward an artificial green fluorescence dye with similar excitation and emission spectra to coral-GFP. In the field, more Symbiodinium were found in traps painted with a green fluorescence dye than in controls. Our results revealed a biological signaling mechanism between the coral host and its potential symbionts.


Assuntos
Cnidários/metabolismo , Cnidários/microbiologia , Dinoflagelados/fisiologia , Fluorescência , Simbiose , Animais , Antozoários/metabolismo , Antozoários/microbiologia , Recifes de Corais , Dinoflagelados/classificação , Filogenia
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