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1.
Sci Total Environ ; 753: 141906, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32890873

RESUMO

Symbiodiniaceae are the source of essential coral symbionts of reef building corals. The growth and density of endosymbiotic Symbiodiniaceae within the coral host is dependent on nutrient availability, yet little is known about how Symbiodiniaceae respond to the dynamics of the nutrients, including switch between different chemical forms and changes in abundance. In this study, we investigated physiological, cytometric, and transcriptomic responses in Fugacium kawagutii to nitrogen (N)-nutrient deficiency and different chemical N forms (nitrate and ammonium) in batch culture conditions. We mainly found that ammonium was consumed faster than nitrate when provided separately, and was preferentially utilized over nitrate when both N compounds were supplied at 1:2, 1:1 and 2:1 molarity ratios. Besides, N-deficiency caused decreases in growth, energy production, antioxidative capacity and investment in photosynthate transport but increased energy consumption. Growing on ammonium produced a similar cell yield as nitrate, but with a reduced investment in nutrient transport and assimilation; yet at high concentrations ammonium exhibited inhibitory effects. These findings together have important implications in N-nutrient regulation of coral symbiosis. In addition, we identified ten highly and stably expressed genes as candidate reference genes, which will be potentially useful for gene expression studies in the future.


Assuntos
Compostos de Amônio , Antozoários , Dinoflagelados , Animais , Nitratos , Transcriptoma
2.
Chemosphere ; 261: 128063, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113659

RESUMO

Paralytic shellfish toxins (PSTs) are a group of natural toxic substances often found in marine bivalves. Accumulation, anatomical distribution, biotransformation and depuration of PSTs in different tissues of bivalves, however, are still not very well understood. In this study, we investigated biokinetics and biotransformation of PSTs in six different tissues, namely gill, mantle, gonad, adductor muscle, kidney, and digestive gland, in Yesso scallops Patinopecten yessoensis exposed to a toxic strain of dinoflagellate Alexandrium pacificum. High daily accumulation rate (DAR) was recorded at the beginning stage of the experiment. Most of the PSTs in toxic algae ingested by scallops were retained and the toxicity level of PSTs in scallops exceeded the regulatory limit within 5 days. At the late stage of the experiment, however, DAR decreased obviously due to the removal of PSTs. Fitting results of the biokinetics model indicated that the amount of PSTs transferred from digestive gland to mantle, adductor muscle, gonad, kidney, and gill in a decreasing order, and adductor muscle, kidney, and gonad had higher removal rate than gill and mantle. Toxin profile in digestive gland was dominated by N-sulfocarbamoyl toxins 1/2 (C1/2), closely resembled that of the toxic algae. In contrast, toxin components in kidney were dominated by high-potency neosaxitoxin (NEO) and saxitoxin (STX), suggesting that the kidney be a major organ for transformation of PSTs.


Assuntos
Dinoflagelados/metabolismo , Pectinidae/efeitos dos fármacos , Pectinidae/metabolismo , Saxitoxina/análogos & derivados , Poluentes Químicos da Água/metabolismo , Animais , Bioacumulação , Biotransformação , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Saxitoxina/metabolismo , Saxitoxina/toxicidade , Toxicocinética , Poluentes Químicos da Água/toxicidade
3.
Mar Environ Res ; 162: 105191, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33075734

RESUMO

Harmful algal blooms produced by the phytoplankton species Karenia brevis and its associated neurotoxin, brevetoxin (PbTx), occur throughout the Gulf of Mexico and have had devastating impacts on co-occurring populations of bottlenose dolphins (Tursiops truncatus), an important marine sentinel species. The majority of documented impacts, however, are from the eastern Gulf of Mexico, with a critical lack of information on the degree and frequency of PbTx exposure in bottlenose dolphins from Texas coastal waters. This study documents PbTx exposure in Texas bottlenose dolphins between 2007 and 2017 and their association with co-occurring K. brevis blooms. PbTx was detected in 60% (n = 112) of the animals tested. Liver tissue samples had the highest frequency of detection (62%), followed by feces (41.4%) and gastric contents (30.4%). PbTx was not detected in urine or intestinal tissue. The concentration ranges of PbTx detected in feces (1.2-216, mean 38.4 ng/g), gastric contents (3.3-1016, mean 158 ng/g) and liver (0.6-52.4, mean 8.5 ng/g) samples were an order of magnitude less than values reported for Florida dolphins for the same sample types. The proportion of dolphins recovered within 4 weeks of a bloom that tested positive for PbTx ('Bloom' group; 75%) was significantly higher compared to those that were recovered 5-8 weeks after termination of a bloom ('Post-Bloom' group; 36%; p = 0.004). The proportion of PbTx-positive animals with no observed bloom association ('Baseline' group; 60%) was also significantly greater than the Post-Bloom group (p = 0.012). No significant difference in proportion of PbTx-positive animals was detected between Bloom and Baseline groups (p = 0.242). No significant differences in liver PbTx concentrations were observed between any pairwise combinations of the 3 exposure groups (p = 0.261). Overall, these findings suggest persistent PbTx exposure for many individuals in these populations, although the health impacts of such exposure are not known.


Assuntos
Golfinho Nariz-de-Garrafa , Dinoflagelados , Animais , Florida , Golfo do México , Proliferação Nociva de Algas , Humanos , Neurotoxinas , Texas
4.
Mar Pollut Bull ; 160: 111609, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32890961

RESUMO

Red tide has always been an environmental issue with global concern. A Noctiluca scintillans red tide and a Mesodinium red tide occurred successively in Yantai nearshore, China, where is usually oligotrophic, in October 2019. Currents, phytoplankton community composition and nutrients were analyzed to access the driving factors of the red tides. The maximum N. scintillans and Mesodiniium abundance reached 124.92 ± 236.84 × 103 cells/L and 1157.52 ± 1294.16 × 103 cells/L respectively. The fast growth of N. scintillans was due to increasing abundance of phytoplankton. The currents were crucial to the assembly and dispersal of red tides. The red tides significantly redistributed the nutrients in the red tide patches and regulated the dominant species in phytoplankton community. Our study illuminates the influence of physical-biochemical coupling processes on red tides, and suggests that ocean dynamics such as currents and tidal factors deserve more attention when considering the ecosystem health problems of coastal zones.


Assuntos
Dinoflagelados , Proliferação Nociva de Algas , China , Ecossistema , Monitoramento Ambiental , Fitoplâncton
5.
Mar Environ Res ; 162: 105125, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32919228

RESUMO

Coral reefs are being degraded worldwide by land reclamation and environmental factors, such as high seawater temperature, resulting in mass bleaching events. In addition, microplastics disturb the formation of coral-algae symbiotic relationships in primary polyps. In our experiments, we observed this effect in the bleached primary polyp Seriatopora caliendrum that lost its symbiont Symbiodiniaceae as a result of high water temperature. There was a higher incorporation of microspheres into bleached corals than in healthy ones. To understand the interference in symbiosis, we used the sea anemone Exaiptasia (as an anthozoan model organism) and fed it with microspheres. TEM results suggested the incorporation of microspheres and symbionts from the same phagocytosis zones in the mesenterial filament and endocytosis by the cells. In the tentacles, microspheres were in the same cell layer as the symbionts. These results suggest that microplastics occupy the spaces inhabited by Symbiodiniaceae, thereby hindering their symbiotic association.


Assuntos
Antozoários , Dinoflagelados , Animais , Recifes de Corais , Endoderma , Microplásticos , Plásticos/toxicidade , Simbiose
6.
Aquat Toxicol ; 228: 105619, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32937230

RESUMO

Commonly affected by changes in climate and environmental conditions, coastal areas are very dynamic environments where shellfish play an important ecological role. In this study, the oxidative stress and genotoxic responses of mussels (Mytilus galloprovincialis) exposed to paralytic shellfish toxin (PST) - producing dinoflagellates Gymnodinium catenatum were evaluated under i) current conditions (CC: 19 °C; pH 8.0), ii) warming (W: 24 °C; pH 8.0), iii) acidification (A:19 °C; pH 7.6) and iv) combined effect of warming and acidification (WA: 24 °C; pH 7.6). Mussels were fed with G. catenatum for 5 days, and to a non-toxic diet during the following 10 days. A battery of oxidative stress biomarkers and comet assay was performed at the peak of toxin accumulation and at the end of the post-exposure phase. Under CC, gills and hepatopancreas displayed different responses/vulnerabilities and mechanisms to cope with PST. While gills presented a tendency for lipid peroxidation (LPO) and genetic damage (expressed by the Genetic Damage Indicator - GDI), hepatopancreas seems to better cope with the toxins, as no LPO was observed. However, the mechanisms involved in hepatopancreas protection were not enough to maintain DNA integrity. The absence of LPO, and the antioxidant system low responsiveness, suggests DNA damage was not oxidative. When exposed to toxic algae under W, toxin-modulated antioxidant responses were observed in both gills and hepatopancreas. Simultaneous exposure to the stressors highlighted gills susceptibility with a synergistic interaction increasing DNA damage. Exposure to toxic algae under A led to genotoxicity potentiation in both organs. The combined effect of WA did not cause relevant interactions in gills antioxidant responses, but stressors interactions impacted LPO and GDI. Antioxidant responses and LPO pointed out to be modulated by the environmental conditions in hepatopancreas, while GDI results support the dominance of toxin-triggered process. Overall, these results reveal that simultaneous exposure to warming, acidification and PSTs impairs mussel DNA integrity, compromising the genetic information due to the synergetic effects. Finally, this study highlights the increasing ecological risk of harmful algal blooms to Mytilus galloprovinciallis populations.


Assuntos
Dano ao DNA , Toxinas Marinhas/toxicidade , Mytilus/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Ensaio Cometa , Dinoflagelados/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/metabolismo , Concentração de Íons de Hidrogênio , Peroxidação de Lipídeos/efeitos dos fármacos , Toxinas Marinhas/metabolismo , Mytilus/genética , Mytilus/metabolismo , Temperatura
7.
Toxicon ; 188: 122-126, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32991938

RESUMO

During a survey of the production of goniodomin A (GDA) by Alexandrium pseudogonyaulax in Danish coastal waters, Krock et al. (2018) obtained mass spectral evidence for the presence of a truncated congener, herein termed GD754, having a molecular weight 14 Da lower than GDA and assigned it as goniodomin B (GDB). An erroneous structure of GDB involving deletion of a methylene group between rings B and D had previously been reported by Espiña et al. (2016) but without experimental details. HPLC properties reported by Krock for GD754 point to it being a homolog of GDA. Comparison of mass spectral fragmentation data reported for GD754 with fragmentation data for GDA, show it to be a truncated form of GDA with the deletion involving a CH2 group from ring F or one of the two methyl substituents on ring F, not elsewhere on the molecule. On biosynthetic grounds, the GD754 congener is proposed to be 34-desmethyl-GDA. Further experimental work will be required to confirm this hypothesis.


Assuntos
Dinoflagelados , Éteres/toxicidade , Macrolídeos/toxicidade , Éteres/química , Macrolídeos/química , Toxinas Biológicas
8.
Mar Environ Res ; 160: 105010, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907730

RESUMO

The underlying mechanisms of bacterioplankton community assembly and interspecies interactions during harmful algal blooms remain largely unclear. Using 16S rRNA gene amplicon sequencing, we analyzed the bacterioplankton communities over the continuous course of saxitoxin-producing Gymnodinium catenatum blooms and two diatom (i.e., Skeletonema costatum and Chaetoceros curvisetus) blooms in an anthropogenically controlled and eutrophic bay, East China Sea. The succession of bacterioplankton communities correlated with changes in the dynamics of algal species. Deterministic versus stochastic bacterioplankton community assemblage processes were quantified, demonstrating that stochastic processes increased when algal blooms happened. The occurrence of algal blooms caused weaker bacterioplankton interspecies interactions and higher degrees of cooperative activities, changed keystone taxa and diminished the stability of bacterial communities. These findings consequently have important implications for our understanding of bacterioplankton community ecology during algal blooms.


Assuntos
Diatomáceas , Dinoflagelados , Proliferação Nociva de Algas , China , Dinoflagelados/genética , Dinoflagelados/crescimento & desenvolvimento , RNA Ribossômico 16S
9.
Mar Environ Res ; 160: 105014, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907732

RESUMO

Alexandrium minutum and Alexandrium pacificum are representatives of the dinoflagellate genus that regularly proliferate on the French coasts and other global coastlines. These harmful species may threaten shellfish harvest and human health due to their ability to synthesize neurotoxic alkaloids of the saxitoxin group. However, some dinoflagellates such as A. minutum, and as reported here A. pacificum as well, may also have a beneficial impact on the environment by producing dimethylsulfoniopropionate-DMSP, the precursor of dimethylsulfur-DMS and sulfate aerosols involved in climate balance. However, environmental conditions might influence Alexandrium physiology towards the production of harmful or environmentally friendly compounds. After assessing the influence of two salinity regimes (33 and 38) relative to each species origin (Atlantic French coast and Mediterranean Lagoon respectively), it appears that DMSP and toxin content was variable between the three experimented strains and that higher salinity disadvantages toxin production and tends to favor the production of the osmolytes DMSP and glycine betaine. Hence, this key metabolite production is strain and species-dependent and is influenced by environmental conditions of salinity which in turn, can diversely affect the environment. Widespread coastal blooms of A. minutum and A. pacificum, although being a risk for seafood contamination with toxins, are also a DMSP and DMS source that potentially contribute to the ecosystem structuration and climate. Regarding recent advances in DMSP biosynthesis pathway, 3 dsyB homologs were found in A. minutum but no homolog of the diatom sequence TpMMT.


Assuntos
Diatomáceas , Dinoflagelados , Ecossistema , Proliferação Nociva de Algas , Humanos , Dinâmica Populacional , Salinidade , Frutos do Mar
10.
Waste Manag ; 118: 435-444, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32971378

RESUMO

Exhausted olive pomace (EOP) represents a potential candidate side stream to be utilized in biotechnological processes. EOP composition includes significant amounts of extractives and pectin, which are both usually discarded and are not utilized in the valorization process of the raw material. In this study, organosolv technology was optimized to remove the extractives and pectin using a Central Composite Rotatable Design. Optimal pretreatment conditions were predicted to be at 97.95 °C for 23.18 min, upon addition of 50% (v/v) EtOH in H2O, with 0.5% (w/v) of H2SO4 as catalyst. The composition analysis of liquid fraction revealed a high content of total sugars (17.58 g/L), galacturonic acid (7.05 g/L) and phenolic compounds (2.97 g/L). The liquid fraction was utilized as a carbon source by the heterotrophic marine microalgae Crypthecodinium cohnii, where it was shown to promote lipid accumulation up to 38.5% wt. of cell biomass, even without any additional detoxification step. This study is the first report that shows the use of galacturonic acid as carbon source for the growth of C. cohnii, while underpinning the use of EOP as a promising substrate for the development of zero-waste bioprocesses.


Assuntos
Dinoflagelados , Ácidos Graxos Ômega-3 , Microalgas , Biomassa , Ácidos Docosa-Hexaenoicos
11.
PLoS One ; 15(9): e0239309, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946494

RESUMO

Limited data coverage on harmful algal blooms (HABs) in some regions makes assessment of long-term trends difficult, and also impedes understanding of bloom ecology. Here, observations reported in a local newspaper were combined with cell count and environmental data from resource management agencies to assess trends in Karenia brevis "red tide" frequency and duration in the Nueces Estuary (Texas) and adjacent coastal waters, and to determine relationships with environmental factors. Based on these analyses, the Coastal Bend region of the Texas coast has experienced a significant increase in the frequency of red tide blooms since the mid-1990s. Salinity was positively correlated with red tide occurrence in the Nueces Estuary, and a documented long-term increase in salinity of the Nueces Estuary may be a major factor in the long-term increase in bloom frequency. This suggests that freshwater inflow management efforts in Texas should consider impacts on red tide habitat suitability (i.e., salinity regime) in downstream estuaries. Natural climate variability such as the El Niño-Southern Oscillation, which is strongly related to rainfall and salinity in Central and South Texas, was also an influential predictor of red tide presence/absence. Though no significant change in the duration of blooms was detected, there was a negative correlation between duration and temperature. Specifically, summer-like temperatures were not favorable to K. brevis bloom development. The relationships found here between red tide frequency/duration and environmental drivers present a new avenue of research that will aid in refining monitoring and forecasting efforts for red tides on the Texas coast and elsewhere. Findings also highlight the importance of factors (i.e., salinity, temperature) that are likely to be altered in the future due to both population growth in coastal watersheds and anthropogenic climate change.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Ecologia , Proliferação Nociva de Algas , Mudança Climática , Dinoflagelados/patogenicidade , Previsões , Golfo do México , Salinidade , Temperatura , Texas
12.
PLoS One ; 15(8): e0238361, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866211

RESUMO

The San Francisco Bay outflow creates a tidally influenced low-salinity plume that affects adjacent coastal sites. In the study region, Anthopleura elegantissima (Cnidaria; Anthozoa) hosts a single symbiont, the dinoflagellate Breviolum muscatinei. Salinity, temperature, and aerial stress induce a bleaching response similar to corals where symbionts are expelled, causing further energetic stress. Using field observations of environmental conditions and symbiont abundance at sites on a gradient of exposure to estuarine outflow, along with a fully crossed multifactorial lab experiment, we tested for changes in symbiont abundance in response to various combinations of three stressors. Lab experiments were designed to mimic short term outflow events with low salinity, high temperature, and aerial exposure treatments. The lab aerial exposure treatment was a statistically significant factor in suppressing symbiont repopulation (ANOVA, p = .017). In the field, symbiont density decreased with increasing tidal height at the site closest to freshwater outflow (ANOVA, p = .007), suggesting that aerial exposure may affect symbiont density more than sea surface temperature and salinity. Unanticipated documentation of survival in 9 months of sand burial and subsequent repopulation of symbionts is reported as a six-month extension to past observations, exemplifying strong tolerance to environmental insult in this Cnidarian mutualism. The study of this symbiosis is useful in examining predicted changes in ocean conditions in tidepool communities and considering relative sources of stress.


Assuntos
Antozoários/fisiologia , Dinoflagelados/fisiologia , Anêmonas-do-Mar/fisiologia , Simbiose/fisiologia , Animais , Água Doce , Temperatura Alta , São Francisco , Temperatura
13.
Ecotoxicol Environ Saf ; 204: 111069, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32758696

RESUMO

We studied the absorption, cytotoxicity and oxidative stress markers of Paralytic Shellfish Toxins (PST) from three extracts from Alexandrium catenella and A. ostenfeldii, in middle Oncorhynchus mykiss intestine in vitro and ex vivo preparations. We measured glutathione (GSH) content, glutathione-S transferase (GST), glutathione reductase (GR) and catalase (CAT) enzymatic activity, and lipid peroxidation in isolated epithelium exposed to 0.13 and 1.3 µM PST. ROS production and lysosomal membrane stability (as neutral red retention time 50%, NRRT50) were analyzed in isolated enterocytes exposed to PST alone or plus 3 µM of the ABCC transport inhibitor MK571. In addition, the concentration-dependent effects of PST on NRRT50 were assayed in a concentration range from 0 to 1.3 µM PST. We studied the effects of three different PST extracts on the transport rate of the ABCC substrate DNP-SG by isolated epithelium. The extract with highest inhibition capacity was selected for studying polarized DNP-SG transport in everted and non-everted intestinal segments. We registered lower GSH content and GST activity, and higher GR activity, with no significant changes in CAT activity, lipid peroxidation or ROS level. PST exposure decreased NRRT50 in a concentration-depend manner (IC50 = 0.0045 µM), but PST effects were not augmented by addition of MK571. All the three PST extracts inhibited ABCC transport activity, but this inhibition was effective only when the toxins were applied to the apical side of the intestine and DNP-SG transport was measured at the basolateral side. Our results indicate that PST are absorbed by the enterocytes from the intestine lumen. Inside the enterocytes, these toxins decrease GSH content and inhibit the basolateral ABCC transporters affecting the normal functions of the cell. Furthermore, PST produce a strong cytotoxic effect to the enterocytes by damaging the lysosomal membrane, even at low, non-neurotoxic concentrations.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Glutationa/análogos & derivados , Mucosa Intestinal/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Oncorhynchus mykiss/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Saxitoxina/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Dinoflagelados/metabolismo , Enterócitos/efeitos dos fármacos , Enterócitos/metabolismo , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Mucosa Intestinal/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lisossomos/metabolismo , Frutos do Mar
14.
Ecotoxicol Environ Saf ; 204: 111004, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32768745

RESUMO

Consumption of seafood contaminated with ciguatoxins (CTXs) leads to a foodborne disease known as ciguatera. Primary producers of CTXs are epibenthic dinoflagellates of the genera Gambierdiscus and Fukuyoa. In this study, thirteen Gambierdiscus and Fukuyoa strains were cultured, harvested at exponential phase, and CTXs were extracted with an implemented rapid protocol. Microalgal extracts were obtained from pellets with a low cell abundance (20,000 cell/mL) and were then analyzed with magnetic bead (MB)-based immunosensing tools (colorimetric immunoassay and electrochemical immunosensor). It is the first time that these approaches are used to screen Gambierdiscus and Fukuyoa strains, providing not only a global indication of the presence of CTXs, but also the ability to discriminate between two series of congeners (CTX1B and CTX3C). Analysis of the microalgal extracts revealed the presence of CTXs in 11 out of 13 strains and provided new information about Gambierdiscus and Fukuyoa toxin profiles. The use of immunosensing tools in the analysis of microalgal extracts facilitates the elucidation of further knowledge regarding these dinoflagellate genera and can contribute to improved ciguatera risk assessment and management.


Assuntos
Ciguatoxinas/isolamento & purificação , Colorimetria/métodos , Dinoflagelados/química , Técnicas Eletroquímicas/métodos , Imunoensaio/métodos , Ciguatoxinas/classificação , Especificidade da Espécie
15.
Mar Pollut Bull ; 160: 111596, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32861933

RESUMO

The effects of two harmful algae Alexandrium tamarense and Gymnodinium catenatum on ecological quality status were identified using biofilm-dwelling ciliate assemblage as test organism communities. The body-size spectra of the test ciliates were observed at a gradient of cell concentrations of both algal species: 100 (control), followed by102, 103, 104 and 105 cells ml-1. The test ciliates showed clear variations in body-size spectra along the concentration gradients of both algal species. In terms of probability density, the ciliates generally peaked at low levels of algal concentrations (100-104 cells ml-1) in small size forms, followed by the forms with large sizes at the concentration of 105 cells ml-1 of both algal species. Bootstrapped-average analysis demonstrated a significant change in body-size spectrum when algal concentrations were higher than 104 cells ml-1. It is suggested that the body-size spectrum of the ciliates may be used to indicate the effects of harmful algal bloom.


Assuntos
Cilióforos , Dinoflagelados , Biofilmes , Ecossistema , Proliferação Nociva de Algas
16.
Aquat Toxicol ; 227: 105591, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32853898

RESUMO

The effects of allelopathy and the potential harm of several isolated allelochemicals have been studied in detail. Microorganisms in the phycosphere play an important role in algal growth, decay and nutrient cycling. However, it is unknown and often neglected whether allelochemicals affect the phycosphere. The present study selected a phenolic acid protocatechuic acid (PA) - previously shown to be an allelochemical. We studied PA at a half maximal effective concentration of 0.20 mM (30 mg L-1) against Scrippsiella trochoidea to assess the effect of PA on its phycosphere in an acute time period (48 h). The results showed that: 1) OTUs (operational taxonomic units) in the treatment groups (31.4 ± 0.55) exceeded those of the control groups (28.2 ± 1.30) and the Shannon and Simpson indices were lower than the control groups (3.31 ± 0.08 and 0.84 ± 0.02, 3.45 ± 0.09 and 0.88 ± 0.01); 2) Gammaproteobacteria predominated in the treatment groups (44.71 ± 2.13 %) while Alphaproteobacteria dominated in the controls (67.17 ± 3.87 %); 3) Gammaproteobacteria and Alphaproteobacteria were important biomarkers in the treatment and control groups respectively (LDA > 4.0). PA improved the relative abundance of Alteromonas significantly and decreased the one of Rhodobacteraceae. PICRUSt analysis showed that the decrease of Rhodobacterceae was closely related with the decline of most functional genes in metabolism such as amino acid, carbohydrate, xenobiotics, cofactors and vitamins metabolism after PA-treated.


Assuntos
Alelopatia/efeitos dos fármacos , Dinoflagelados/efeitos dos fármacos , Proliferação Nociva de Algas/efeitos dos fármacos , Hidroxibenzoatos/farmacologia , Microbiota/efeitos dos fármacos , Feromônios/farmacologia , Alelopatia/genética , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Dinoflagelados/genética , Dinoflagelados/crescimento & desenvolvimento , Microbiota/genética , Proteobactérias/efeitos dos fármacos , Proteobactérias/genética , Proteobactérias/isolamento & purificação
17.
Mar Pollut Bull ; 158: 111441, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32736204

RESUMO

Ostreopsis is a benthic dinoflagellate genus comprising eleven species including seven that are toxigenic. Ostreopsis lenticularis was first described from French Polynesia and is widely distributed in many insular locations from the Pacific Ocean. The current study presents morphological and molecular evidence of the presence of O. lenticularis at the Fernando de Noronha Archipelago, South Atlantic. Light microscopy and scanning electron microscopy of field cells showed morphological features in agreement with the description of O. lenticularis. Cells were broadly oval, 66.0-117.5 µm in dorso-ventral diameter, 50.0-92.5 µm in width, with thecal plates presenting two kinds of pores. Phylogenetic analyses based on LSU (D1-D3) and ITS sequences from field cells from Fernando de Noronha clustered with O. lenticularis sequences from elsewhere. The species was present in low to high abundances. The current study expands the distribution of O. lenticularis to Fernando de Noronha Archipelago in the South Atlantic Ocean.


Assuntos
Dinoflagelados , Oceano Atlântico , Oceano Pacífico , Filogenia , Polinésia
18.
Mar Pollut Bull ; 158: 111400, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753185

RESUMO

The dinoflagellate Karlodinium veneficum has worldwide distribution and is associated with harmful algal blooms through the production of karlotoxins. We investigated the allelopathy and toxicity to explore the potential ecological implications. Prorocentrum donghaiense was inhibited significantly when grown either in co-cultures or in culture filtrate of K. veneficum. In addition, the effect of the co-occurring microalga species (P. donghaiense) on the hemolytic activity of K. veneficum was also evaluated. P. donghaiense did not inhibit the growth of K. veneficum but increased the hemolytic activity. The culture of K. veneficum was loaded onto an RP-C18 column and eluted with different percentages of aqueous methanol solution. 80% methanol fraction not only inhibited the growth of P. donghaiense by allelopathy but also exhibited strong hemolytic activity, indicating that the allelochemicals and toxins of K. veneficum might be the same components. Furthermore, KmTx 3 (C68H124O24) was identified using HPLC-HRMS from this fraction.


Assuntos
Dinoflagelados , Alelopatia , Proliferação Nociva de Algas
19.
Mar Pollut Bull ; 158: 111414, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753198

RESUMO

Diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTX) produced by endemic species of the genus Dinophysis, mainly D. acuta and D. acuminata, pose a big threat to public health, artisanal fisheries and the aquaculture industry in Southern Chile. This work reports the first detection of lipophilic toxins, including pectenotoxin-2 (PTX-2) and gymnodimine-A (GYM-A), in hard razor clam (Tagelus dombeii) associated with an unprecedented spring bloom -38.4 × 103 cells L-1 in integrated hose sampler (0-10 m) - of Dinophysis acuminata in coastal waters of central Chile. The socio-economic challenges to small-scale fisheries are discussed. The study points to the pressing need for sound policies to face unexpected HAB event, probably due to biogeographical expansions, with a focus on fisheries management, participation of stakeholders, and development of adaptive capacities.


Assuntos
Dinoflagelados , Toxinas Marinhas , Intoxicação por Frutos do Mar , Animais , Chile , Frutos do Mar/análise
20.
Toxicon ; 186: 19-25, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32738246

RESUMO

The first survey of the phycotoxin profile in mussels (Mytilus galloprovincialis) from the coastal waters of Bosnia and Herzegovina (The Bay of Neum, Middle Adriatic Sea) in correlation to the Makarska City Bay (Croatia, Middle Adriatic Sea) was conducted in 2017. Throughout the monitoring period, occasions of gymnodimine (GYM) and azaspiracid (AZA2) shellfish toxicity were recorded in concentrations that do not endanger human health. The occurrence of yessotoxins (YTXs), the most common toxins found in the Adriatic Sea, was correlated to the presence of the Gonyaulax species, a potential source of YTX. The DSP group of toxins is represented by the ester-OA. Phytoplankton analysis confirmed the presence of dinoflagellates from the Prorocentrum genus, a species associated with DSP toxicity. Occurrence frequency and variability of toxin composition were investigated in conjunction to physico-chemical parameters in the surrounding sea water. In the central Adriatic Sea, the infestation period ranges in general from June to August. However, the depuration phase extended beyond September in the Bay of Neum, increasing the length of the decontamination period.


Assuntos
Toxinas Marinhas/análise , Venenos de Moluscos/análise , Frutos do Mar/estatística & dados numéricos , Animais , Croácia , Dinoflagelados , Compostos Heterocíclicos com 3 Anéis/análise , Humanos , Hidrocarbonetos Cíclicos/análise , Iminas/análise , Mytilus , Oxocinas/análise , Fitoplâncton , Alimentos Marinhos , Intoxicação por Frutos do Mar , Compostos de Espiro/análise
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