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1.
PLoS One ; 15(3): e0230176, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32150599

RESUMO

Diarrheic Shellfish Poisoning toxins (DST) are a severe health risk to shellfish consumers and can be a major problem for the shellfish industry. Bivalve molluscs can accumulate DST via ingestion of toxic dinoflagellates like Dinophysis spp., which are the most prominent producers of DST. The effects of DST-containing dinoflagellate Dinophysis acuta on bivalve clearance and respiration rate were investigated in the blue mussel (Mytilus edulis) exposed to different algal densities in a controlled laboratory study. Results showed that M. edulis exposed to D. acuta displayed a reduced clearance rate compared to M. edulis exposed to equivalent bio-volumes of the non-toxic cryptophyte Rhodomonas salina. Furthermore, M. edulis ceased to feed on D. acuta after 1 to 4 h, depending on D. acuta densities. The quickest response was observed at the highest densities of D. acuta. The estimated total amount of DST accumulated in the M. edulis exceeded the regulatory limit for human consumption and furthermore, intoxication of the M. edulis seemed to occur faster at high cell toxicity rather than at high cell density. However, respiration rates were, similar, irrespective of whether M. edulis were fed single diets of R. salina, D. acuta or a mixed diet of both algal species. In conclusion, the DST-containing D. acuta had a severe negative effect on the clearance of M. edulis, which can affect the conditions of the M. edulis negatively. Hence, DST may cause low quality M. edulis, due to reduced feeding when exposed to DST-containing D. acuta.


Assuntos
Dinoflagelados/patogenicidade , Toxinas Marinhas/efeitos adversos , Mytilus edulis/parasitologia , Intoxicação por Frutos do Mar/parasitologia , Animais , Dieta/métodos , Ingestão de Alimentos/fisiologia , Monitoramento Ambiental/métodos , Humanos , Taxa Respiratória , Alimentos Marinhos/parasitologia
2.
PLoS One ; 15(2): e0228414, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32032360

RESUMO

As reef-building corals are increasingly being exposed to persistent threats that operate on both regional and global scales, there is a pressing need to better understand the complex processes that diminish coral populations. This study investigated the impacts of the Florida red tide dinoflagellate Karenia brevis and associated brevetoxins on selected facets of coral biology using Porites astreoides as a model system. When provided with choice assays, P. astreoides larvae were shown to actively avoid seawater containing red tide (5×105 cells L-1-7.6×106 cells L-1) or purified brevetoxins (0.018 µg mL-1 brevetoxin-2 and 0.0018 µg mL-1 brevetoxin-3). However, forced exposure to similar treatments induced time-dependent physiological and behavioral changes that were captured by PAM fluorometry and settlement and survival assays, respectively. Adult fragments of P. astreoides exposed to red tide or associated brevetoxins displayed signs of proteomic alterations that were characterized by the use of an iTRAQ-based quantitative proteomic analysis. The novel use of this technique with P. astreoides demonstrated that protein regulation was highly contingent upon biological versus chemical treatment (i.e. live K. brevis vs. solely brevetoxin exposure) and that several broad pathways associated with cell stress were affected including redox homeostasis, protein folding, energy metabolism and reactive oxygen species production. The results herein provide new insight into the ecology, behavior and sublethal stress of reef-building corals in response to K. brevis exposure and underscore the importance of recognizing the potential of red tide to act as a regional stressor to these important foundation species.


Assuntos
Dinoflagelados/patogenicidade , Ecossistema , Exposição Ambiental/efeitos adversos , Proliferação Nociva de Algas/fisiologia , Larva/metabolismo , Toxinas Marinhas/toxicidade , Oxocinas/toxicidade , Proteoma/análise , Animais , Proliferação Nociva de Algas/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Proteômica
3.
Chemosphere ; 241: 124968, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31606578

RESUMO

The solute carriers (SLCs) are membrane proteins that transport many endogenous and exogenous substances such as xenobiotic toxins. Bivalve mollusks, mainly feeding on microalgae, show marked capacity to accumulate paralytic shellfish toxins (PSTs), the most common and hazardous marine biotoxins produced by dinoflagellates. Exploring the SLCs related to PST accumulation in bivalve could benefit our understanding about the mechanisms of PST bioavailability in bivalve and the adaptations of these species. Herein, we provided the first systematic analysis of SLC genes in mollusks, which identified 673 SLCs (PySLCs, 48 subfamilies) in Yesso scallop (Patinopecten yessoensis), 510 (48 subfamilies) in Pacific oyster (Crassostrea gigas), and 350 (47 subfamilies) in gastropod owl limpet (Lottia gigantea). Significant expansion of subfamilies SLC5, SLC6, SLC16, and SLC23 in scallop, and SLC46 subfamily in both scallop and oyster were revealed. Different PySLC members were highly expressed in the developmental stages and adult tissues, and hepatopancreas harboured more specifically expressed PySLCs than other tissues/organs. After feeding the scallops with PST-producing dinoflagellate, 131 PySLCs were regulated and more than half of them were from the expanded subfamilies. The trend of expression fold change in regulated PySLCs was consistent with that of PST changes in hepatopancreas, implying the possible involvement of these PySLCs in PST transport and homeostasis. In addition, the PySLCs from the expanded subfamily were revealed to be under positive selection, which might be related to lineage-specific adaptation to the marine environments with algae derived biotoxins.


Assuntos
Dinoflagelados/patogenicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Pectinidae/genética , Proteínas Carreadoras de Solutos/genética , Animais , Transporte Biológico , Dinoflagelados/metabolismo , Homeostase , Intoxicação por Frutos do Mar , Toxinas Biológicas/toxicidade
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.
PLoS One ; 13(6): e0199306, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29912948

RESUMO

Blooms of the toxic dinoflagellates Karlodinium armiger and K. veneficum are frequently observed in Alfacs Bay, Spain, causing mass mortality to wild and farmed mussels. An isolate of K. armiger from Alfacs Bay was grown in the laboratory and exposed to adults, embryos and trochophore larvae of the blue mussel, Mytilus edulis. Adult mussels rejected to filter K. armiger at cell concentrations >1.5·103 cells ml-1. Exposure of adult mussels (23-33 mm shell length) to a range of K. armiger cell concentrations led to mussel mortality with LC50 values of 9.4·103 and 6.1·103 cells ml-1 after 24 and 48 h exposure to ~3.6·104 K. armiger cells ml-1, respectively. Karlodinium armiger also affected mussel embryos and trochophore larvae and feeding by K. armiger on both embryos and larvae was observed under the microscope. Embryos exposed to low K. armiger cell concentrations suffered no measurable mortality. However, at higher K. armiger cell concentrations the mortality of the embryos increased significantly with cell concentration and reached 97% at 1.8·103 K. armiger cells ml-1 after 29 h of exposure. Natural K. armiger blooms may not only have serious direct effects on benthic communities, but may also affect the recruitment of mussels in affected areas.


Assuntos
Dinoflagelados/patogenicidade , Ecossistema , Larva/parasitologia , Mytilus edulis/parasitologia , Animais , Organismos Aquáticos/parasitologia , Mytilus edulis/crescimento & desenvolvimento , Espanha
6.
PLoS One ; 13(2): e0192237, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29474370

RESUMO

In the blue crab, Callinectes sapidus, early studies suggested a relationship between smaller crabs, which molt more frequently, and higher rates of infection by the dinoflagellate parasite, Hematodinium perezi. In order to better explore the influence of size and molting on infections, blue crabs were collected from the Maryland coastal bays and screened for the presence of H. perezi in hemolymph samples using a quantitative PCR assay. Molt stage was determined by a radioimmunoassay which measured ecdysteroid concentrations in blue crab hemolymph. Differences were seen in infection prevalence between size classes, with the medium size class (crabs 61 to 90 mm carapace width) and juvenile crabs (≤ 30 mm carapace width) having the highest infection prevalence at 47.2% and 46.7%, respectively. All size classes were susceptible to infection, although fall months favored disease acquisition by juveniles, whereas mid-sized animals (31-90 mm carapace width) acquired infection predominantly in summer. Disease intensity was also most pronounced in the summer, with blue crabs > 61 mm being primary sources of proliferation. Molt status appeared to be influenced by infection, with infected crabs having significantly lower concentrations of ecdysteroids than uninfected crabs in the spring and the fall. We hypothesize that infection by H. perezi may increase molt intervals, with a delay in the spring molt cycle as an evolutionary adaptation functioning to coincide with increased host metabolism, providing optimal conditions for H. perezi propagation. Regardless of season, postmolt crabs harbored significantly higher proportions of moderate and heavy infections, suggesting that the process of ecdysis, and the postmolt recovery period, has a positive effect on parasite proliferation.


Assuntos
Crustáceos/fisiologia , Dinoflagelados/patogenicidade , Muda , Animais , Reação em Cadeia da Polimerase , Radioimunoensaio , Estações do Ano
7.
J Invertebr Pathol ; 152: 8-16, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29355502

RESUMO

The parasitic dinoflagellate Hematodinium perezi is highly prevalent in juvenile blue crabs, Callinectes sapidus, along the eastern seaboard of the USA. Although the parasite is known to kill adult crabs, the mortality rate of naturally infected juvenile crabs remains unknown. We analyzed the influence of temperature and salinity on the mortality of recently recruited blue crabs that were naturally infected with H. perezi. Over 492 juvenile crabs (infected, n = 282; uninfected controls, n = 210) were held individually in six-well plates and held at six temperatures (4, 10, 15, 20, 25, and 30 °C) or three salinities (5, 15, and 30 psu) for a maximum of 90 days. Mortality of infected crabs was 10 times higher at elevated temperatures (25 and 30 °C) and salinity (30 psu) compared to uninfected control treatments. By contrast, infected crabs exposed to mild temperatures (10, 15, and 20 °C) showed a high survival (>80%), no different than uninfected control treatments. Infected crabs at the lowest temperature (4 °C) exhibited a high mortality, but the intensity of infection was lower than in the other temperature treatments. In addition, this study revealed the optimal temperature (25 °C) and salinity (30 psu) for H. perezi to progress in its life cycle leading to sporulation in juvenile crabs; 31.6% (19/60) of crabs held under these conditions released dinospores of H. perezi after 10 days. Crabs held at other temperatures did not release dinospores over the time course of the experiment. Infected crabs were capable of molting and in most cases molted at the same frequency as uninfected crabs serving as controls. The mortality observed in this study indicates that early benthic juveniles will experience significant mortality due to H. perezi with increasing ocean temperatures and that this mortality may be a significant factor in the recruitment of blue crabs to high salinity regions.


Assuntos
Braquiúros/parasitologia , Dinoflagelados/patogenicidade , Salinidade , Temperatura , Animais , Interações Hospedeiro-Parasita , Estimativa de Kaplan-Meier
8.
Physiol Rep ; 5(23)2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29199178

RESUMO

The fluted giant clam, Tridacna squamosa, lives in symbiosis with zooxanthellae which reside extracellularly inside a tubular system. Zooxanthellae fix inorganic carbon (Ci) during insolation and donate photosynthate to the host. Carbonic anhydrases catalyze the interconversion of CO2 and HCO3-, of which carbonic anhydrase 2 (CA2) is the most ubiquitous and involved in many biological processes. This study aimed to clone a CA2 homolog (CA2-like) from the fleshy and colorful outer mantle as well as the thin and whitish inner mantle of T. squamosa, to determine its cellular and subcellular localization, and to examine the effects of light exposure on its gene and protein expression levels. The cDNA coding sequence of CA2-like from T. squamosa comprised 789 bp, encoding 263 amino acids with an estimated molecular mass of 29.6 kDa. A phenogramic analysis of the deduced CA2-like sequence denoted an animal origin. CA2-like was not detectable in the shell-facing epithelium of the inner mantle adjacent to the extrapallial fluid. Hence, CA2-like is unlikely to participate directly in light-enhanced calcification. By contrast, the outer mantle, which contains the highest density of tertiary tubules and zooxanthellae, displayed high level of CA2-like expression, and CA2-like was localized to the tubule epithelial cells. More importantly, exposure to light induced significant increases in the protein abundance of CA2-like in the outer mantle. Hence, CA2-like could probably take part in the increased supply of inorganic carbon (Ci) from the host clam to the symbiotic zooxanthellae when the latter conduct photosynthesis to fix Ci during light exposure.


Assuntos
Bivalves/enzimologia , Anidrase Carbônica II/metabolismo , Exoesqueleto/metabolismo , Animais , Bivalves/parasitologia , Dióxido de Carbono/metabolismo , Anidrase Carbônica II/química , Anidrase Carbônica II/genética , Dinoflagelados/patogenicidade , Células Epiteliais/metabolismo , Células Epiteliais/efeitos da radiação , Luz Solar , Simbiose
9.
Curr Biol ; 27(11): 1645-1651.e3, 2017 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-28528902

RESUMO

"X-cells" have long been associated with tumor-like formations (xenomas) in marine fish, including many of commercial interest. The name was first used to refer to the large polygonal cells that were found in epidermal xenomas from flatfish from the Pacific Northwest [1]. Similar looking cells from pseudobranchial xenomas had previously been reported from cod in the Atlantic [2] and Pacific Oceans [3]. X-cell pathologies have been reported from five teleost orders: Pleuronectiformes (flatfish), Perciformes (perch-like fish), Gadiformes (cods), Siluriformes (catfish), and Salmoniformes (salmonids). Various explanations have been elicited for their etiology, including being adenomas or adenocarcinomas [4, 5], virally transformed fish cells [6-8], or products of coastal pollution [9, 10]. It was hypothesized that X-cells were protozoan parasites [1, 11-13], and although recent molecular analyses have confirmed this, they have failed to place them in any phylum [14-18], demonstrating weak phylogenetic associations with the haplosporidians [16] or the alveolates [15]. Here, we sequenced rRNA genes from European and Japanese fish that are known to develop X-cell xenomas. We also generated a metagenomic sequence library from X-cell xenomas of blue whiting and Atlantic cod and assembled 63 X-cell protein-coding genes for a eukaryote-wide phylogenomic analysis. We show that X-cells group in two highly divergent clades, robustly sister to the bivalve parasite Perkinsus. We formally describe these as Gadixcellia and Xcellia and provide a phylogenetic context to catalyze future research. We also screened Atlantic cod populations for xenomas and residual pathologies and show that X-cell infections are more prevalent and widespread than previously known.


Assuntos
Dinoflagelados/genética , Doenças dos Peixes/parasitologia , Peixes/parasitologia , Parasitos/genética , Filogenia , Animais , Dinoflagelados/patogenicidade , Doenças dos Peixes/epidemiologia , Deriva Genética , Metagenômica , Oceanos e Mares , Parasitos/patogenicidade , Prevalência
10.
PLoS One ; 11(7): e0159563, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27427938

RESUMO

The effect of the dinoflagellate, Alexandrium fundyense, on relative expression of glutathione S-transferase (GST) transcripts was examined in the copepod Calanus finmarchicus. Adult females were fed for 5-days on one of three experimental diets: control (100% Rhodomonas spp.), low dose of A. fundyense (25% by volume, 75% Rhodomonas spp.), and high dose (100% A. fundyense). Relative expression of three GST genes was measured using RT-qPCR on days 0.5, 1, 2 and 5 in two independent experiments. Differential regulation was found for the Delta and the Sigma GSTs between 0.5 to 2 days, but not on day 5 in both experiments. The third GST, a microsomal, was not differentially expressed in either treatment or day. RT-qPCR results from the two experiments were similar, even though experimental females were collected from the Gulf of Maine on different dates and their reproductive output differed. In the second experiment, expression of 39 GSTs was determined on days 2 and 5 using RNA-Seq. Global gene expression analyses agreed with the RT-qPCR results. Furthermore, the RNA-Seq measurements indicated that only four GSTs were differentially expressed under the experimental conditions, and the response was small in amplitude. In summary, the A. fundyense diet led to a rapid and transient response in C. finmarchicus in three cytosolic GSTs, while a fourth GST (Omega I) was significantly up-regulated on day 5. Although there was some regulation of GSTs in response the toxic dinoflagellate, the tolerance to A. fundyense by C. finmarchicus is not dependent on the long-term up-regulation of specific GSTs.


Assuntos
Proteínas de Artrópodes/genética , Copépodes/genética , Glutationa Transferase/genética , Inativação Metabólica/genética , Toxinas Marinhas/toxicidade , Animais , Proteínas de Artrópodes/metabolismo , Copépodes/efeitos dos fármacos , Copépodes/metabolismo , Dinoflagelados/patogenicidade , Dinoflagelados/fisiologia , Feminino , Cadeia Alimentar , Regulação da Expressão Gênica , Glutationa Transferase/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Maine , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Análise de Sequência de RNA
11.
Proc Biol Sci ; 283(1829)2016 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-27122557

RESUMO

Understanding interactions between harmful algal bloom (HAB) species and their grazers is essential for determining mechanisms of bloom proliferation and termination. We exposed the common calanoid copepod, Temora longicornis to the HAB species Alexandrium fundyense and examined effects on copepod survival, ingestion, egg production and swimming behaviour. A. fundyense was readily ingested by T. longicornis and significantly altered copepod swimming behaviour without affecting copepod survival or fitness. A. fundyense caused T. longicornis to increase their swimming speed, and the straightness of their path long after the copepods had been removed from the A. fundyense treatment. Models suggest that these changes could lead to a 25-56% increase in encounter frequency between copepods and their predators. This work highlights the need to determine how ingesting HAB species alters grazer behaviour as this can have significant impacts on the fate of HAB toxins in marine systems.


Assuntos
Copépodes/microbiologia , Copépodes/fisiologia , Proliferação Nociva de Algas , Fitoplâncton/patogenicidade , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Copépodes/efeitos dos fármacos , Dinoflagelados/patogenicidade , Ecossistema , Cadeia Alimentar , Interações Hospedeiro-Patógeno , Modelos Biológicos , Neurotoxinas/análise , Neurotoxinas/toxicidade , Natação
12.
Environ Sci Technol ; 49(24): 14230-8, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26580419

RESUMO

Paralytic shellfish poisoning (PSP) is a serious human illness caused by the ingestion of seafood contaminated with saxitoxin and its derivatives (STXs). These toxins are produced by some species of marine dinoflagellates within the genus Alexandrium. In the Mediterranean Sea, toxic Alexandrium spp. blooms, especially of A. minutum, are frequent and intense with negative impact to coastal ecosystem, aquaculture practices and other economic activities. We conducted a large scale study on the sxt gene and toxin distribution and content in toxic dinoflagellate A. minutum of the Mediterranean Sea using both quantitative PCR (qPCR) and HILIC-HRMS techniques. We developed a new qPCR assay for the estimation of the sxtA1 gene copy number in seawater samples during a bloom event in Syracuse Bay (Mediterranean Sea) with an analytical sensitivity of 2.0 × 10° sxtA1 gene copy number per reaction. The linear correlation between sxtA1 gene copy number and microalgal abundance and between the sxtA1 gene and STX content allowed us to rapidly determine the STX-producing cell concentrations of two Alexandrium species in environmental samples. In these samples, the amount of sxtA1 gene was in the range of 1.38 × 10(5) - 2.55 × 10(8) copies/L and the STX concentrations ranged from 41-201 nmol/L. This study described a potential PSP scenario in the Mediterranean Sea.


Assuntos
Dinoflagelados/patogenicidade , Monitoramento Ambiental/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Saxitoxina/genética , Intoxicação por Frutos do Mar , Dinoflagelados/genética , Ecossistema , Marcadores Genéticos , Humanos , Mar Mediterrâneo , Microalgas/genética , Saxitoxina/toxicidade , Água do Mar/parasitologia , Intoxicação por Frutos do Mar/parasitologia
13.
J Huazhong Univ Sci Technolog Med Sci ; 35(5): 773-780, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26489638

RESUMO

This review briefly describes the origin, chemistry, molecular mechanism of action, pharmacology, toxicology, and ecotoxicology of palytoxin and its analogues. Palytoxin and its analogues are produced by marine dinoflagellates. Palytoxin is also produced by Zoanthids (i.e. Palythoa), and Cyanobacteria (Trichodesmium). Palytoxin is a very large, non-proteinaceous molecule with a complex chemical structure having both lipophilic and hydrophilic moieties. Palytoxin is one of the most potent marine toxins with an LD50 of 150 ng/kg body weight in mice exposed intravenously. Pharmacological and electrophysiological studies have demonstrated that palytoxin acts as a hemolysin and alters the function of excitable cells through multiple mechanisms of action. Palytoxin selectively binds to Na(+)/K(+)-ATPase with a Kd of 20 pM and transforms the pump into a channel permeable to monovalent cations with a single-channel conductance of 10 pS. This mechanism of action could have multiple effects on cells. Evaluation of palytoxin toxicity using various animal models revealed that palytoxin is an extremely potent neurotoxin following an intravenous, intraperitoneal, intramuscular, subcutaneous or intratracheal route of exposure. Palytoxin also causes non-lethal, yet serious toxic effects following dermal or ocular exposure. Most incidents of palytoxin poisoning have manifested after oral intake of contaminated seafood. Poisonings in humans have also been noted after inhalation, cutaneous/systemic exposures with direct contact of aerosolized seawater during Ostreopsis blooms and/or through maintaining aquaria containing Cnidarian zoanthids. Palytoxin has a strong potential for toxicity in humans and animals, and currently this toxin is of great concern worldwide.


Assuntos
Acrilamidas/toxicidade , Antozoários/patogenicidade , Dinoflagelados/patogenicidade , Toxinas Marinhas/toxicidade , Alga Marinha/patogenicidade , Acrilamidas/química , Acrilamidas/isolamento & purificação , Animais , Antozoários/fisiologia , Venenos de Cnidários , Dinoflagelados/fisiologia , Cães , Cobaias , Haplorrinos , Humanos , Dose Letal Mediana , Toxinas Marinhas/química , Toxinas Marinhas/isolamento & purificação , Camundongos , Coelhos , Ratos , Alga Marinha/fisiologia , Intoxicação por Frutos do Mar/fisiopatologia , ATPase Trocadora de Sódio-Potássio/metabolismo
14.
PLoS One ; 10(7): e0133549, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26197230

RESUMO

Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35%) and also the major producer of superoxide radicals (14 pmol cell-1 hr-1) especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1). Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD) and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content), respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 µg mL-1) and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1) could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST) GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability), whereas crude methanol and acetone extracts of Chattonella, Fibrocapsa, Heterosigma, Karlodinium and Prymnesium decreased cell viability down to 0%. These and our previous findings involving the role of fatty acids confirm that superoxide radicals are only partially involved in ichthyotoxicity and point to a highly variable contribution by other compounds such as lipid peroxidation products (e.g. aldehydes).


Assuntos
Eutrofização , Ácidos Graxos/metabolismo , Toxinas Marinhas/metabolismo , Oncorhynchus mykiss/microbiologia , Oxocinas/metabolismo , Superóxidos/metabolismo , Animais , Catalase/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Dinoflagelados/patogenicidade , Brânquias/metabolismo , Haptófitas/patogenicidade , Concentração de Íons de Hidrogênio , L-Lactato Desidrogenase/metabolismo , Peroxidação de Lipídeos , Toxinas Marinhas/química , Microalgas/patogenicidade , Oncorhynchus mykiss/metabolismo , Oxocinas/química , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
15.
PLoS One ; 10(6): e0129344, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26035592

RESUMO

This study investigated effects of microalgae (Rhodomonas baltica) and heterotrophic protists (Oxyrrhis marina) on the daily growth, activity, condition and feeding success of Atlantic herring (Clupea harengus) larvae from hatch, through the end of the endogenous (yolk sac) period. Yolk sac larvae were reared in the presence and absence of microplankton and, each day, groups of larvae were provided access to copepods. Larvae reared with microalgae and protists exhibited precocious (2 days earlier) and ≥ 60% increased feeding incidence on copepods compared to larvae reared in only seawater (SW). In the absence and presence of microalgae and protists, life span and growth trajectories of yolk sac larvae were similar and digestive enzyme activity (trypsin) and nutritional condition (RNA-DNA ratio) markedly declined in all larvae directly after yolk sac depletion. Thus, microplankton promoted early feeding but was not sufficient to alter life span and growth during the yolk sac phase. Given the importance of early feeding, field programs should place greater emphasis on the protozooplankton-ichthyoplankton link to better understand match-mismatch dynamics and bottom-up drivers of year class success in marine fish.


Assuntos
Dinoflagelados/patogenicidade , Peixes/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Microalgas/patogenicidade , Saco Vitelino/crescimento & desenvolvimento , Animais , Peixes/parasitologia , Larva/parasitologia , Infecções por Protozoários/parasitologia , Natação , Saco Vitelino/parasitologia
16.
Mar Pollut Bull ; 89(1-2): 209-219, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25444620

RESUMO

To explore the genetic diversity and paralytic shellfish poisoning (PSP) toxin profile of the Alexandrium tamarense species complex along the coast of China, 67 strains of A. tamarense from the China Sea were collected and genetic diversity were analyzed based on the rDNA sequences. In addition, PSP toxin compositions and contents were detected by HPLC. According to the 5.8S rDNA and ITS, and LSU rDNA D1-D2 sequence, A. tamarense in the China Sea comprises at least Group IV and Group I ribotypes. In these Chinese strains, the toxins with the highest concentration in the profile were C1/2, gonyautoxins 1/4 (GTX1/4) and neosaxitoxin (NEO). However, the toxin profiles were atypical and C1/2 toxins were not detected in some strains. No strict correlation was observed between the PSP toxins profile and the geographical distribution.


Assuntos
Dinoflagelados/classificação , Dinoflagelados/genética , Filogenia , China , Cromatografia Líquida de Alta Pressão , DNA Ribossômico , Dinoflagelados/patogenicidade , Variação Genética , Genética Populacional , Humanos , Saxitoxina/análogos & derivados , Saxitoxina/análise , Intoxicação por Frutos do Mar
17.
BMC Res Notes ; 7: 722, 2014 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-25314922

RESUMO

BACKGROUND: The Mediterranean mussel Mytilus galloprovincialis is marine bivalve with a relevant commercial importance as well as a key sentinel organism for the biomonitoring of environmental pollution. Here we report the RNA sequencing of the mussel digestive gland, performed with the aim: a) to produce a high quality de novo transcriptome assembly, thus improving the genetic and molecular knowledge of this organism b) to provide an initial assessment of the response to paralytic shellfish poisoning (PSP) on a molecular level, in order to identify possible molecular markers of toxin accumulation. RESULTS: The comprehensive de novo assembly and annotation of the transcriptome yielded a collection of 12,079 non-redundant consensus sequences with an average length of 958 bp, with a high percentage of full-length transcripts. The whole-transcriptome gene expression study indicated that the accumulation of paralytic toxins produced by the dinoflagellate Alexandrium minutum over a time span of 5 days scarcely affected gene expression, but the results need further validation with a greater number of biological samples and naturally contaminated specimens. CONCLUSION: The digestive gland reference transcriptome we produced significantly improves the data collected from previous sequencing efforts and provides a basic resource for expanding functional genomics investigations in M. galloprovincialis. Although not conclusive, the results of the RNA-seq gene expression analysis support the classification of mussels as bivalves refractory to paralytic shellfish poisoning and point out that the identification molecular biomarkers of PSP in the digestive gland of this organism is problematic.


Assuntos
Sistema Digestório/parasitologia , Dinoflagelados/patogenicidade , Monitoramento Ambiental/métodos , Perfilação da Expressão Gênica , Mytilus/genética , Infecções por Protozoários/genética , Análise de Sequência de RNA , Intoxicação por Frutos do Mar/genética , Transcriptoma , Animais , Sistema Digestório/anatomia & histologia , Dinoflagelados/metabolismo , Cadeia Alimentar , Marcadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Parasita , Toxinas Marinhas/metabolismo , Mytilus/anatomia & histologia , Mytilus/parasitologia , Infecções por Protozoários/metabolismo , Intoxicação por Frutos do Mar/metabolismo
18.
Eukaryot Cell ; 13(11): 1439-49, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25239978

RESUMO

The regulatory circuits during infection of dinoflagellates by their parasites are largely unknown on the molecular level. Here we provide molecular insights into these infection dynamics. Alexandrium tamarense is one of the most prominent harmful algal bloom dinoflagellates. Its pathogen, the dinoflagellate parasitoid Amoebophrya sp., has been observed to infect and control the blooms of this species. We generated a data set of transcripts from three time points (0, 6, and 96 h) during the infection of this parasite-host system. Assembly of all transcript data from the parasitoid (>900,000 reads/313 Mbp with 454/Roche next-generation sequencing [NGS]) yielded 14,455 contigs, to which we mapped the raw transcript reads of each time point of the infection cycle. We show that particular surface lectins are expressed at the beginning of the infection cycle which likely mediate the attachment to the host cell. In a later phase, signal transduction-related genes together with transmembrane transport and cytoskeleton proteins point to a high integration of processes involved in host recognition, adhesion, and invasion. At the final maturation stage, cell division- and proliferation-related genes were highly expressed, reflecting the fast cell growth and nuclear division of the parasitoid. Our molecular insights into dinoflagellate parasitoid interactions point to general mechanisms also known from other eukaryotic parasites, especially from the Alveolata. These similarities indicate the presence of fundamental processes of parasitoid infection that have remained stable throughout evolution within different phyla.


Assuntos
Proteínas do Citoesqueleto/genética , Dinoflagelados/parasitologia , Dinoflagelados/patogenicidade , Proteínas de Membrana Transportadoras/genética , Sequência de Bases , Adesão Celular/genética , Divisão Celular/genética , Proliferação de Células/genética , Dinoflagelados/genética , Regulação da Expressão Gênica/genética , Proliferação Nociva de Algas , Lectinas/biossíntese , Lectinas/genética , Análise de Sequência de RNA , Transdução de Sinais/genética , Esporos de Protozoários/genética
19.
J Wildl Dis ; 49(2): 246-60, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23568900

RESUMO

Harmful algal bloom events caused by the dinoflagellate Karenia brevis occurred along the central west Florida, USA, coast from February 2005 through December 2005 and from August 2006 through December 2006. During these events, from 4 February 2005 through 28 November 2006, live, debilitated seabirds admitted for rehabilitation showed clinical signs that included disorientation, inability to stand, ataxia, and seizures. Testing of blood, biologic fluids, and tissues for brevetoxin by enzyme-linked immunosorbent assay found toxin present in 69% (n=95) of rehabilitating seabirds. Twelve of the 19 species of birds had evidence of brevetoxin exposure. Commonly affected species included Double-crested Cormorants (Phalacrocorax auritus), Brown Pelicans (Pelecanus occidentalis), Great Blue Herons (Ardea herodias), and Common Loons (Gavia immer). Serial blood and fecal samples taken from several live seabirds during rehabilitation showed that brevetoxin was cleared within 5-10 days after being admitted to the rehabilitation facility, depending on the species tested. Among seabirds that died or were euthanized, the highest brevetoxin concentrations were found in bile, stomach contents, and liver. Most dead birds had no significant pathologic findings at necropsy, thereby supporting brevetoxin-related mortality.


Assuntos
Doenças das Aves/epidemiologia , Dinoflagelados/patogenicidade , Surtos de Doenças/veterinária , Toxinas Marinhas/análise , Oxocinas/análise , Infecções Protozoárias em Animais/epidemiologia , Animais , Doenças das Aves/mortalidade , Doenças das Aves/patologia , Aves , Causas de Morte , Dinoflagelados/metabolismo , Feminino , Florida/epidemiologia , Masculino , Toxinas Marinhas/toxicidade , Oxocinas/toxicidade , Infecções Protozoárias em Animais/mortalidade , Infecções Protozoárias em Animais/patologia , Especificidade da Espécie
20.
Sci Total Environ ; 447: 255-66, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23391892

RESUMO

Routine monitoring along the coast of the Gulf of Maine (GoM) reveals shellfish toxicity nearly every summer, but at varying times, locations, and magnitudes. The responsible toxin is known to be produced by the dinoflagellate Alexandrium fundyense, yet there is little apparent association between Alexandrium abundance and shellfish toxicity. One possibility is that toxic cells are persistent in offshore areas and variability in shellfish toxicity is caused not by changes in overall abundance, but rather by variability in transport processes. Measurements of offshore Alexandrium biomass are scarce, so we bypass cell abundance as an explanatory variable and focus instead on the relations between shellfish toxicity and concurrent metrics of GoM meteorology, hydrology, and oceanography. While this yields over two decades (1985-2005) of data representing a variety of interannual conditions, the toxicity data are gappy in spatial and temporal coverage. We address this through a combination of parametric curve fitting and hierarchical cluster analysis to reveal eight archetypical modes of seasonal toxicity timing. Groups of locations are then formed that have similar interannual patterns in these archetypes. Finally, the interannual patterns within each group are related to available environmental metrics using classification trees. Results indicate that a weak cross-shore sea surface temperature (SST) gradient in the summer is the strongest correlate of shellfish toxicity, likely by signifying a hydrological connection between offshore Alexandrium populations and near-shore shellfish beds. High cumulative downwelling wind strength early in the season is revealed as a precursor consistent with this mechanism. Although previous studies suggest that alongshore transport is important in moving Alexandrium from the eastern to western GoM, alongshore SST gradient is not an important correlate of toxicity in our study. We conclude by discussing the implications of our results for designing efficient and effective shellfish monitoring programs along the GoM coast.


Assuntos
Dinoflagelados/fisiologia , Dinoflagelados/patogenicidade , Conceitos Meteorológicos , Frutos do Mar/parasitologia , Frutos do Mar/toxicidade , Animais , Análise por Conglomerados , Eutrofização , Modelos Teóricos , Mytilus/parasitologia , Reprodutibilidade dos Testes , Estações do Ano , Intoxicação por Frutos do Mar/parasitologia
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