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1.
Mar Pollut Bull ; 150: 110734, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910516

RESUMO

The effects of ecologically relevant concentrations of Irgarol 1051, a representative PSII herbicide, on hermatypic corals were studied in the laboratory. The colour and chlorophyll fluorescence of Acropora tenuis were examined following exposure to around ambient concentrations of Irgarol 1051 (20 ng/L and 200 ng/L) for 7 days. While the colour of corals was stable throughout the experiment at both concentrations, the maximum effective quantum yield (ΔF/Fm') of symbiotic dinoflagellates decreased with increasing Irgarol 1051 concentration (day 7: 8%, 20 ng/L; 37%, 200 ng/L). The expression of heat shock protein (HSP) 70 and 90 in symbiotic dinoflagellates was upregulated after 7 days exposure to both Irgarol concentrations, whereas HSP90 in coral was not upregulated. The findings of the present study suggest that the threshold of chlorophyll fluorescence and HSP expression in symbiotic dinoflagellates is lower than 20 ng/L, which is around ecologically relevant concentrations in tropical to subtropical waters.


Assuntos
Antozoários/fisiologia , Dinoflagelados/fisiologia , Triazinas/análise , Poluentes Químicos da Água/análise , Animais , Água do Mar
2.
Sci Total Environ ; 704: 135430, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31818571

RESUMO

Protein levels were assessed in the dinoflagellate Lingulodinium polyedra over the course of a diurnal cycle using a label-free LC-MS/MS approach. Roughly 1700 proteins were quantitated in a triplicate dataset over a daily period, and 13 were found to show significant rhythmic changes. Included among the proteins found to be most abundant at night were the two bioluminescence proteins, luciferase and luciferin binding protein, as well as a proliferating cell nuclear protein involved in the nightly DNA replication. Aconitase and a pyrophosphate fructose-6-phosphate-1-phosphotransferase were also found to be more abundant at night, suggestive of an increased ability to generate ATP by glucose catabolism when photosynthesis does not occur. Among the proteins more abundant during the day were found a 2-epi-5-epi-valiolone synthase, potentially involved in synthesis of mycosporin-like amino acids that can act as a "microbial sunscreen", and an enzyme synthesizing vitamin B6 which is known to protect against oxidative stress. A lactate oxidoreductase was also found to be more abundant during the day, perhaps to counteract the pH changes due to carbon fixation by facilitating conversion of pyruvate to lactate. This unbiased proteomic approach reveals novel insights into the daily metabolic changes of this dinoflagellate. Furthermore, the observation that only a limited number of proteins vary support a model where metabolic flux through pathways can be controlled by variations in a select few, possibly rate limiting, steps. Data are available via ProteomeXchange with identifier PXD006994.


Assuntos
Dinoflagelados/fisiologia , Proteoma , Aclimatação , Cromatografia Líquida , Fotossíntese , Proteômica , Espectrometria de Massas em Tandem
3.
Sci Total Environ ; 699: 134323, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31522044

RESUMO

Harmful algal blooms (HABs) have increased as a result of global climate and environmental changes, exerting increasing impacts on the aquatic ecosystem, coastal economy, and human health. Despite great research efforts, our understanding on the drivers of HABs is still limited in part because HAB species' physiology is difficult to probe in situ. Here, we used molecular ecological analyses to characterize a dinoflagellate bloom at Xiamen Harbor, China. Prorocentrum donghaiense was identified as the culprit, which nutrient bioassays showed were not nutrient-limited. Metatranscriptome profiling revealed that P. donghaiense highly expressed genes related to N- and P-nutrient uptake, phagotrophy, energy metabolism (photosynthesis, oxidative phophorylation, and rhodopsin) and carbohydrate metabolism (glycolysis/gluconeogenesis, TCA cycle and pentose phosphate) during the bloom. Many genes in P. donghaiense were up-regulated at night, including phagotrophy and environmental communication genes, and showed active expression in mitosis. Eight microbial defense genes were up-regulated in the bloom compared with previously analyzed laboratory cultures. Furthermore, 76 P. donghaiense microRNA were identified from the bloom, and their target genes exhibited marked differences in amino acid metabolism between the bloom and cultures and the potential of up-regulated antibiotic and cell communication capabilities. These findings, consistent with and complementary to recent reports, reveal major metabolic processes in P. donghaiense potentially important for bloom formation and provide a gene repertoire for developing bloom markers in future research.


Assuntos
Dinoflagelados/fisiologia , Monitoramento Ambiental , Redes e Vias Metabólicas/genética , Ecossistema , Proliferação Nociva de Algas , MicroRNAs
4.
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
5.
Sensors (Basel) ; 19(19)2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31561600

RESUMO

We present a model that estimates the spectral phytoplankton absorption coefficient ( a p h ( λ ) ) of four phytoplankton groups (picophytoplankton, nanophytoplankton, dinoflagellates, and diatoms) as a function of the total chlorophyll-a concentration (C) and sea surface temperature (SST). Concurrent data on a p h ( λ ) (at 12 visible wavelengths), C and SST, from the surface layer (<20 m depth) of the North Atlantic Ocean, were partitioned into training and independent validation data, the validation data being matched with satellite ocean-colour observations. Model parameters (the chlorophyll-specific phytoplankton absorption coefficients of the four groups) were tuned using the training data and found to compare favourably (in magnitude and shape) with results of earlier studies. Using the independent validation data, the new model was found to retrieve total a p h ( λ ) with a similar performance to two earlier models, using either in situ or satellite data as input. Although more complex, the new model has the advantage of being able to determine a p h ( λ ) for four phytoplankton groups and of incorporating the influence of SST on the composition of the four groups. We integrate the new four-population absorption model into a simple model of ocean colour, to illustrate the influence of changes in SST on phytoplankton community structure, and consequently, the blue-to-green ratio of remote-sensing reflectance. We also present a method of propagating error through the model and illustrate the technique by mapping errors in group-specific a p h ( λ ) using a satellite image. We envisage the model will be useful for ecosystem model validation and assimilation exercises and for investigating the influence of temperature change on ocean colour.


Assuntos
Modelos Teóricos , Fitoplâncton/fisiologia , Oceano Atlântico , Clorofila/análogos & derivados , Cor , Diatomáceas/fisiologia , Dinoflagelados/fisiologia , Luz , Imagens de Satélites , Temperatura Ambiente
6.
Sci Total Environ ; 692: 1037-1047, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539936

RESUMO

Dinoflagellates represent major contributors to the harmful algal blooms in the oceans. Phosphorus (P) is an essential macronutrient that limits the growth and proliferation of dinoflagellates. However, the specific molecular mechanisms involved in the P acclimation of dinoflagellates remain poorly understood. Here, the transcriptomes of a dinoflagellate Prorocentrum donghaiense grown under inorganic P-replete, P-deficient, and inorganic- and organic P-resupplied conditions were compared. Genes encoding low- and high-affinity P transporters were significantly down-regulated in the P-deficient cells, while organic P utilization genes were significantly up-regulated, indicating strong ability of P. donghaiense to utilize organic P. Up-regulation of membrane phospholipid catabolism and endocytosis provided intracellular and extracellular organic P for the P-deficient cells. Physiological responses of P. donghaiense to dissolved inorganic P (DIP) or dissolved organic P (DOP) resupply exhibited insignificant differences. However, the corresponding transcriptomic responses significantly differed. Although the expression of multiple genes was significantly altered after DIP resupplementation, few biological processes varied. In contrast, various metabolic processes associated with cell growth, such as translation, transport, nucleotide, carbohydrate and lipid metabolisms, were significantly altered in the DOP-resupplied cells. Our results indicated that P. donghaiense evolved diverse DOP utilization strategies to adapt to low P environments, and that DOPs might play critical roles in the P. donghaiense bloom formation.


Assuntos
Dinoflagelados/fisiologia , Fósforo/metabolismo , Poluentes da Água/metabolismo , Regulação para Baixo , Proliferação Nociva de Algas , Oceanos e Mares , Transcriptoma , Regulação para Cima
7.
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 Ambiente
8.
Mar Pollut Bull ; 149: 110507, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421568

RESUMO

This study focused on the bloom-developing process of the giant jellyfish, Nemopilema nomurai, on phytoplankton and microzooplankton communities. Two repeated field observations on the jellyfish bloom were conducted in June 2012 and 2014 in the southern Yellow Sea where blooms of N. nomurai were frequently observed. We demonstrated that the bloom was made up of two stages, namely the developing stage and the mature stage. Total chlorophyll a increased and the concentrations of inorganic nutrients decreased during the developing stage, while both concentrations maintained stable and at low levels during the mature stage. Our analysis revealed that phosphate excreted by growing N. nomurai promoted the growth of phytoplankton at the developing stage. At the mature stage, size compositions of microzooplankton were altered and tended to be smaller via a top-down process, while phytoplankton compositions, affected mainly through a bottom-up process, shifted to be less diatoms and cryptophytes but more dinoflagellates.


Assuntos
Fitoplâncton/crescimento & desenvolvimento , Cifozoários/fisiologia , Zooplâncton/fisiologia , Animais , Biomassa , China , Clorofila A/análise , Diatomáceas/fisiologia , Dinoflagelados/fisiologia , Oceanos e Mares , Fosfatos/metabolismo
9.
ISME J ; 13(10): 2489-2499, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31186513

RESUMO

The ability of corals and other cnidarians to survive climate change depends partly on the composition of their endosymbiont communities. The dinoflagellate family Symbiodiniaceae is genetically and physiologically diverse, and one proposed mechanism for cnidarians to acclimate to rising temperatures is to acquire more thermally tolerant symbionts. However, cnidarian-dinoflagellate associations vary in their degree of specificity, which may limit their capacity to alter symbiont communities. Here, we inoculated symbiont-free polyps of the sea anemone Exaiptasia pallida (commonly referred to as 'Aiptasia'), a model system for the cnidarian-dinoflagellate symbiosis, with simultaneous or sequential mixtures of thermally tolerant and thermally sensitive species of Symbiodiniaceae. We then monitored symbiont success (relative proportional abundance) at normal and elevated temperatures across two to four weeks. All anemones showed signs of bleaching at high temperature. During simultaneous inoculations, the native, thermally sensitive Breviolum minutum colonized polyps most successfully regardless of temperature when paired against the non-native but more thermally tolerant Symbiodinium microadriaticum or Durusdinium trenchii. Furthermore, anemones initially colonized with B. minutum and subsequently exposed to S. microadriaticum failed to acquire the new symbiont. These results highlight how partner specificity may place strong limitations on the ability of certain cnidarians to acquire more thermally tolerant symbionts, and hence their adaptive potential under climate change.


Assuntos
Dinoflagelados/fisiologia , Anêmonas-do-Mar/fisiologia , Aclimatação , Animais , Temperatura Alta , Modelos Biológicos , Especificidade da Espécie , Simbiose
10.
Biomolecules ; 9(6)2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31207942

RESUMO

This research work was carried out to determine the effects of water contamination on the fatty acid (FA) profile of periphyton, zoobenthos, two Chinese carps and a common carp (Hypophthalmichthys molitrix, Ctenopharygodon idella and Cyprinus carpio), captured from highly polluted (HP), less polluted (LP), and non-polluted (NP) sites of the Indus river. We found that the concentration of heavy metals in the river water from the polluted locations exceeded the permissible limits suggested by the World Health Organization (WHO) and the US Environmental Protection Agency (EPA). Fatty acid profiles in periphyton, zoobenthos, H. molitrix, C. idella, and C. carpio in the food web of river ecosystems with different pollution levels were assessed. Lauric acid and arachidic acids were not detected in the biomass of periphyton and zoobenthos from HP and LP sites compared to NP sites. Alpha-linolenic acid (ALA), eicosadienoic acid and docosapentaenoic acid were not recorded in the biomass samples of periphyton and zoobenthos in both HP and LP sites. Caprylic acid, lauric acid, and arachidic acid were not found in H. molitrix, C. idella, and C. carpio captured from HP. In this study, 6 and 9 omega series FAs were identified in the muscle samples of H. molitrix, C. idella and C. carpio captured from HP and LP sites compared to NP sites, respectively. Less polyunsaturated fatty acids were observed in the muscle samples of H. molitrix, C. idella, and C. carpio collected from HP than from LP. The heavy metals showed significant negative correlations with the total FAs in periphyton, zoobenthos, and fish samples.


Assuntos
Dinoflagelados/metabolismo , Ácidos Graxos/metabolismo , Peixes/metabolismo , Cadeia Alimentar , Água Doce , Microalgas/metabolismo , Poluição da Água , Animais , Dinoflagelados/efeitos dos fármacos , Dinoflagelados/fisiologia , Peixes/fisiologia , Metais Pesados/toxicidade , Microalgas/efeitos dos fármacos , Microalgas/fisiologia , Estresse Fisiológico/efeitos dos fármacos
11.
Integr Comp Biol ; 59(4): 845-855, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31150064

RESUMO

Coral reefs are faced with almost complete destruction by the end of the century due to global warming unless humanity can cap global temperature rise. There is now a race to develop a diverse set of solutions to save coral reefs. In this perspective, a case is made for understanding the cell biology of coral-dinoflagellate symbiosis to help inform development of solutions for saving reefs. Laboratory model systems for the study of coral symbiosis, including the sea anemone Exaiptasia pallida, are featured as valuable tools in the fight to save corals. The roles of host innate immunity and inter-partner nutrient dynamics in the onset, ongoing maintenance, and dysregulation of symbiosis are reviewed and discussed. Key innate immune genes and pathways, such as glycan-lectin interactions, the sphingosine rheostat, and the cytokine transforming growth factor beta are shown to modulate a host immune response in the symbiotic state. An upset in the homeostatic inorganic nutrient balance during heat stress and high exogenous nutrient availability is credited with driving the partnership toward dysregulation and coral bleaching. Specific examples are given where knowledge of the cell biology of symbiosis is informing the development of solutions, including studies showing clear limitations in the value of partner switching and acclimatization protocols. Finally, emphasis is placed on rapid advancement of knowledge to try to meet the urgent need for solutions. This includes real-time open communication with colleagues on successes and failures, sharing of resources and information, and working together in the spirit of a collective mission to save coral reefs.


Assuntos
Antozoários/fisiologia , Dinoflagelados/fisiologia , Imunidade Inata , Simbiose/fisiologia , Animais , Antozoários/genética , Antozoários/imunologia , Recifes de Corais , Aquecimento Global , Imunidade Inata/genética , Nutrientes/fisiologia , Anêmonas-do-Mar/genética , Anêmonas-do-Mar/imunologia , Anêmonas-do-Mar/fisiologia , Estresse Fisiológico , Simbiose/imunologia
12.
Environ Sci Pollut Res Int ; 26(20): 20439-20453, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31102217

RESUMO

The seasonal succession of phytoplankton functional groups (PFGs), their ecological preferences, relationships between environmental variables and PFGs, and ecological status were investigated in the Batman Dam Reservoir, a warm monomictic reservoir, located in the Tigris River basin of Turkey. Altogether 60 species, 19 functional groups, and 10 prevailing functional groups were identified, and prevailing functional groups showed strong seasonal changes. Centric diatoms Cyclotella ocellata (group B) and Aulacoseira granulata (group P) were dominant in the spring, with water mixing and low temperature. Groups F (Elakatothrix gelatinosa, Elakatothrix gelatinosa, and Sphaerocystis schroeteri), J (Pediastrum simplex and Coelastrum reticulatum), G (Eudorina elegans and Volvox aureus), LM (Ceratium and Microcystis), and H1 (Aphanizomenon flos-aquae and Anabaena spiroides) dominated the phytoplankton community from summer to mid-autumn, with thermal stratification. Groups H1 and P became dominant in the late autumn, with the breakdown of stratification. With the deepening of the mixing zone, groups P and T (Mougeotia sp.) were dominant in the winter. The reservoir was meso-eutrophic according to trophic state index values based on total phosphorus (TP), chlorophyll a, Secchi depth and total nitrogen, habitat preferences of PFGs, and diversity indices of phytoplankton. Redundancy analysis (RDA) revealed that NO3-N, SiO2, TP, pH, and water temperature (WT) were the most important environmental factors controlling PFGs in the BDR. Weighted averaging regression results indicated that among PFGs, groups F and T had a narrower tolerance range for WT, pH, and SiO2, while groups G and T had a narrower tolerance range for TP and NO3-N.


Assuntos
Cianobactérias/fisiologia , Diatomáceas , Fitoplâncton/fisiologia , Clorofila A , Dinoflagelados/fisiologia , Ecossistema , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Água Doce/química , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Fósforo/análise , Estações do Ano , Dióxido de Silício/análise , Temperatura Ambiente , Turquia
13.
ISME J ; 13(9): 2334-2345, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31118473

RESUMO

The acquisition of thermally tolerant algal symbionts by corals has been proposed as a natural or assisted mechanism of increasing coral reef resilience to anthropogenic climate change, but the cell-level processes determining the performance of new symbiotic associations are poorly understood. We used liquid chromatography-mass spectrometry to investigate the effects of an experimentally induced symbiosis on the host proteome of the model sea anemone Exaiptasia pallida. Aposymbiotic specimens were colonised by either the homologous dinoflagellate symbiont (Breviolum minutum) or a thermally tolerant, ecologically invasive heterologous symbiont (Durusdinium trenchii). Anemones containing D. trenchii exhibited minimal expression of Niemann-Pick C2 proteins, which have predicted biochemical roles in sterol transport and cell recognition, and glutamine synthetases, which are thought to be involved in nitrogen assimilation and recycling between partners. D. trenchii-colonised anemones had higher expression of methionine-synthesising betaine-homocysteine S-methyltransferases and proteins with predicted oxidative stress response functions. Multiple lysosome-associated proteins were less abundant in both symbiotic treatments compared with the aposymbiotic treatment. The differentially abundant proteins are predicted to represent pathways that may be involved in nutrient transport or resource allocation between partners. These results provide targets for specific experiments to elucidate the mechanisms underpinning compensatory physiology in the coral-dinoflagellate symbiosis.


Assuntos
Dinoflagelados/fisiologia , Proteoma/genética , Anêmonas-do-Mar/microbiologia , Simbiose , Animais , Recifes de Corais , Dinoflagelados/química , Dinoflagelados/genética , Temperatura Alta , Estresse Oxidativo , Proteínas/genética , Proteínas/metabolismo , Proteoma/metabolismo , Proteômica , Anêmonas-do-Mar/genética , Anêmonas-do-Mar/fisiologia
14.
Fish Shellfish Immunol ; 90: 173-179, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31059815

RESUMO

It is well documented that diarrhetic shellfish poisoning (DSP) toxins have strong genetic toxicity, cytotoxicity and oxidative damage to bivalve species. However, these toxic effects seem to decrease with the extension of exposure time and the increment of the toxin concentration, the mechanism involved remained unclear, though. In this paper, we found that expression of the genes related to cytoskeleton and Nrf2 signaling pathway displayed different changes over time in the gill of Perna viridis after exposure to DSP toxins-producing microalga Prorocentrum lima. During the short-term exposure (3 h and 6 h), KEAP1 gene expression was significantly up-regulated, coupled with up-regulation of MRP, ABCB1 and CAT transcriptions and down-regulation of GPx1 and NQO1 mRNA. After longer exposure to high density of P. lima, Nrf2 was significantly up-regulated, accompanied with up-regulation of Nrf2 pathway related genes such as NQO1, SOD, GST-ω and ABCB1, whereas KEAP1 was down-regulated. TUBA1C and TUBB1 transcripts were significantly down-regulated after short-term exposure of P. lima, but both of them were up-regulated at 96 h after exposure to high density of P. lima. Paraffin section demonstrated that P. lima had a strong damage on the gill of mussels during the short-term exposure. However, the negative effect to the gill decreased, and the gill restored after longer exposure (96 h). Taking together, we proposed that P. lima had a negative impact on cytoskeleton of mussel gill tissue, could cause oxidative damage to the gills. However, longer exposure of P. lima in high density could activate Nrf2 signaling pathway, thereby reducing the influence of toxin on mussel. Our study might provide a novel clue for the resistance mechanism of shellfish to DSP toxins.


Assuntos
Antioxidantes/metabolismo , Dinoflagelados/fisiologia , Toxinas Marinhas/efeitos adversos , Fator 2 Relacionado a NF-E2/genética , Perna (Organismo)/genética , Animais , Elementos de Resposta Antioxidante/imunologia , Fator 2 Relacionado a NF-E2/metabolismo , Perna (Organismo)/efeitos dos fármacos , Perna (Organismo)/enzimologia , Perna (Organismo)/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/imunologia , Regulação para Cima
15.
Mar Pollut Bull ; 141: 1-8, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955713

RESUMO

As mariculture expands offshore in response to the increasing demand for seafood, a new set of ecological concerns arises. We report on presented phosphate and silicate deficiencies in spring in the Zhangzi Island area, northern Yellow Sea, used for farming scallops. Silicon limitation was observed at up to 77.3% of stations, with an average silicate concentration as low as 1.7 µM in March 2014. Average phosphate concentration decreased from 0.12 to 0.05 µM from March to May. Stoichiometric ratios and absolute concentrations indicate that 78%-90% of stations showed phosphate limitation. Correspondingly, the phytoplankton community shifted from predominately diatoms to dinoflagellates. The higher frequency of nutrient limitation in farmed areas, compared with unseeded areas and northern Yellow Sea in general, imply intensified bottom-up controls on scallop production. The "bottle-neck" effect of limited food availability in spring suggests that carrying capacity was originally overestimated, when calculated from annual primary production.


Assuntos
Aquicultura/métodos , Diatomáceas/fisiologia , Dinoflagelados/fisiologia , Fitoplâncton/fisiologia , Animais , China , Nutrientes , Pectinidae , Fosfatos/análise , Estações do Ano
16.
Mar Pollut Bull ; 141: 550-560, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955767

RESUMO

The relative importance of organic nitrogen (ON) and inorganic nitrogen (IN) as nitrogen sources for the phytoplankton communities were studied through a seasonal time series of nitrogen species in the eastern Arabian Sea. Seasonal data on nitrogen species showed that ON dominates the system throughout the year and account for >90% of the total nitrogen (TN) during north east monsoon (NEM). The average ON concentration in the study region was 11.5 µM during NEM as compared to 7.2 µM during south west monsoon (SWM). The contribution of picoplankton to the total phytoplankton pool (fpico) increased from 19% during SWM to 36% in NEM. Along with cyanobacteria, the diatoms Thalassionema nitzchoides and Thalassiosira sp. and among the dinoflagellates Pronoctiluca sp. were found to proliferate in ON rich waters. We suggest atmospheric deposition, riverine-input, resuspension of bottom sediment and ground water intrusion as the possible sources of ON in the study region.


Assuntos
Nitrogênio/análise , Fitoplâncton/fisiologia , Cianobactérias/fisiologia , Diatomáceas/fisiologia , Dinoflagelados/fisiologia , Monitoramento Ambiental , Índia , Oceano Índico , Estações do Ano
17.
Mar Pollut Bull ; 141: 621-628, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955777

RESUMO

Corals inhabit oligotrophic waters, thriving amidst limited nutrients such as nitrogen and phosphorous. When nutrient levels increase, usually due to human activity, the symbiosis of dinoflagellates (family Symbiodiniaceae) with scleractinian corals can break down. Although gorgonian corals dominate many Caribbean reefs, the impact of enrichment on them and their algae is understudied. We exposed two gorgonian species, Pseudoplexaura porosa and Eunicea tourneforti, to elevated concentrations of either ammonium (10 µM or 50 µM) or phosphate (4 µM). Enrichment with 10 µM ammonium increased chlorophyll content and algal density in both species, whereas the host biochemical composition was unaffected. Exposure to 50 µM ammonium only reduced the quantum yield in P. porosa and mitotic indices in both species. Conversely, algal carbon and nitrogen content within E. tourneforti increased with 4 µM phosphate exposure. These gorgonian species coped with short-term nutrient enrichment, furthering our understanding of the success of Caribbean gorgonians.


Assuntos
Antozoários/fisiologia , Dinoflagelados/fisiologia , Nitrogênio/metabolismo , Fósforo/metabolismo , Amônia/metabolismo , Animais , Carbono , Região do Caribe , Clorofila , Nutrientes/metabolismo , Fosfatos/metabolismo , Simbiose
18.
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 Ambiente
19.
Sci Total Environ ; 676: 62-71, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31029901

RESUMO

Dinoflagellate blooms are the results of rapid cell proliferation governed by cell cycle, a highly-ordered series of events that culminates in cell division. However, little is known about cell cycle progression of the in situ bloom cells. Here, we compared proteomes of the in situ blooming cells of a dinoflagellate Prorocentrum donghaiense collected at different cell cycle phases. The blooming P. donghaiense cells completed a cell cycle within 24 h with a high synchronization rate of 82.7%. Proteins associated with photosynthesis, porphyrin and chlorophyll synthesis, carbon, nitrogen and amino acid metabolisms exhibited high expressions at the G1 phase; DNA replication and mismatch repair related proteins were more abundant at the S phase; while protein synthesis and oxidative phosphorylation were highly enriched at the G2/M phase. Cell cycle proteins presented similar periodic diel patterns to other eukaryotic cells, and higher expressions of proliferating cell nuclear antigen and cyclin dependent kinase 2 at the S phase ensured the smooth S-G2/M transition. Strikingly, four histones were first identified in P. donghaiense and highly expressed at the G2/M phase, indicating their potential roles in regulating cell cycle. This study presents the first quantitative survey, to our knowledge, of proteome changes at different cell cycle phases of the in situ blooming cells in natural environment and provides insights into cell cycle regulation of the blooming dinoflagellate cells.


Assuntos
Dinoflagelados/fisiologia , Eutrofização/fisiologia , Proteoma/metabolismo , Proteômica , Carbono , Ciclo Celular , Nitrogênio , Fotossíntese
20.
PLoS One ; 14(3): e0213519, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30849101

RESUMO

Zooxanthellate corals live in symbiosis with phototrophic dinoflagellates of the family Symbiodiniaceae, enabling the host coral to dwell in shallow, nutrient-poor marine waters. The South Atlantic Ocean is characterized by low coral diversity with high levels of endemism. However, little is known about coral-dinoflagellate associations in the region. This study examined the diversity of Symbiodiniaceae associated with the scleractinian coral Favia gravida across its distributional range using the ITS-2 marker. This brooding coral endemic to the South Atlantic can be found across a wide range of latitudes and longitudes, including the Mid-Atlantic islands. Even though it occurs primarily in shallower environments, F. gravida is among the few coral species that live in habitats with extreme environmental conditions (high irradiance, temperature, and turbidity) such as very shallow tide pools. In the present study, we show that F. gravida exhibits some degree of flexibility in its symbiotic association with zooxanthellae across its range. F. gravida associates predominantly with Cladocopium C3 (ITS2 type Symbiodinium C3) but also with Symbiodinium A3, Symbiodinium linucheae (ITS2 type A4), Cladocopium C1, Cladocopium C130, and Fugacium F3. Symbiont diversity varied across biogeographic regions (Symbiodinium A3 and S. linucheae were found in the Tropical Eastern Atlantic, Cladocopium C1 in the Mid-Atlantic, and other subtypes in the Southwestern Atlantic) and was affected by local environmental conditions. In addition, Symbiodiniaceae diversity was highest in a southwestern Atlantic oceanic island (Rocas Atoll). Understanding the relationship between corals and their algal symbionts is critical in determining the factors that control the ecological niches of zooxanthellate corals and their symbionts, and identifying host-symbiont pairs that may be more resistant to environmental changes.


Assuntos
Antozoários , Recifes de Corais , Dinoflagelados/fisiologia , Modelos Biológicos , Simbiose/fisiologia , Animais , Antozoários/microbiologia , Antozoários/fisiologia , Filogeografia
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