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1.
Motor Control ; : 1-14, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38710480

RESUMO

Motor imagery (MI) is frequently used in tennis players. This pilot study aimed to assess whether the MI modality and preference of skilled tennis players could influence their service performance when using MI before serving first balls. Twenty expert players (Mage = 18.6 years) completed the movement imagery questionnaire (third version) to assess their MI modality scores (internal visual, external visual, and kinesthetic) and their MI preference. Participants completed 4 experimental counterbalanced sessions spread over 4 weeks, each including the completion of 20 first-serve balls in match condition. The sessions included a control condition (i.e., only physical practice trials) and three MI conditions during which the players had to mentally imagine themselves performing a serve according to one of the imagery modalities, either internal visual, external visual, or kinesthetic, before serving. The percentage of success, the speed of the service balls (measured by a tablet with SWING VISION and a radar gun), and an efficiency score were recorded and then evaluated by experts and served as performance indicators and dependent variables. The results of this study showed that players benefited from MI before serving and that almost a third of the participants achieved a higher percentage of success and efficiency scores when using their preferred MI modality. These results lead us, in an applied way, to suggest to skilled tennis players to determine their MI preference and to have recourse to the mental simulation of a successful serve before serving the first balls in match condition.

2.
Environ Res ; 162: 144-151, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29306662

RESUMO

Ciguatoxins (CTXs) are lipid-soluble polyether compounds produced by dinoflagellates from the genus Gambierdiscus spp. typically found in tropical and subtropical zones. This endemic area is however rapidly expanding due to environmental perturbations, and both toxic Gambierdiscus spp. and ciguatoxic fishes have been recently identified in the North Atlantic Ocean (Madeira and Canary islands) and Mediterranean Sea. Ciguatoxins bind to Voltage Gated Sodium Channels on the membranes of sensory neurons, causing Ciguatera Fish Poisoning (CFP) in humans, a disease characterized by a complex array of gastrointestinal, neurological, neuropsychological, and cardiovascular symptoms. Although CFP is the most frequently reported non bacterial food-borne poisoning worldwide, there is still no simple and quick way of detecting CTXs in contaminated samples. In the prospect to engineer rapid and easy-to-use CTXs live cells-based tests, we have studied the effects of CTXs on the yeast Saccharomyces cerevisiae, a unicellular model which displays a remarkable conservation of cellular signalling pathways with higher eukaryotes. Taking advantage of this high level of conservation, yeast strains have been genetically modified to encode specific transcriptional reporters responding to CTXs exposure. These yeast strains were further exposed to different concentrations of either purified CTX or micro-algal extracts containing CTXs. Our data establish that CTXs are not cytotoxic to yeast cells even at concentrations as high as 1µM, and cause an increase in the level of free intracellular calcium in yeast cells. Concomitantly, a dose-dependent activation of the calcineurin signalling pathway is observed, as assessed by measuring the activity of specific transcriptional reporters in the engineered yeast strains. These findings offer promising prospects regarding the potential development of a yeast cells-based test that could supplement or, in some instances, replace current methods for the routine detection of CTXs in seafood products.


Assuntos
Calcineurina , Ciguatoxinas , Saccharomyces cerevisiae/metabolismo , Animais , Calcineurina/efeitos dos fármacos , Calcineurina/metabolismo , Ciguatera , Ciguatoxinas/análise , Ciguatoxinas/toxicidade , Humanos , Mar Mediterrâneo , Saccharomyces cerevisiae/efeitos dos fármacos , Espanha
3.
Vaccine ; 35(14): 1782-1788, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28317660

RESUMO

In a single-center study, 66 healthy volunteers aged between 18 and 50years were randomized to be immunized against rabies with three different injection routes: intradermal with DebioJect™ (IDJ), standard intradermal with classical needle (IDS), also called Mantoux method, and intramuscular with classical needle (IM). "Vaccin rabique Pasteur®" and saline solution (NaCl 0.9%) were administered at D0, D7 and D28. Antigen doses for both intradermal routes were 1/5 of the dose for IM. Tolerability, safety and induced immunogenicity of IDJ were compared to IDS and IM routes. Pain was evaluated at needle insertion and at product injection for all vaccination visits. Solicited Adverse Event (SolAE) and local reactogenicity symptoms including pain, redness and pruritus were recorded daily following each vaccination visit. Adverse events (AE) were recorded over the whole duration of the study. Humoral immune response was measured by assessing the rabies virus neutralizing antibody (VNA) titers using Rapid Fluorescent Focus Inhibition Test (RFFIT). Results demonstrated that the DebioJect™ is a safe, reliable and efficient device. Significant decreases of pain at needle insertion and at vaccine injection were reported with IDJ compared to IDS and IM. All local reactogenicity symptoms (pain, redness and pruritus) after injection with either vaccine or saline solution, were similar for IDJ and IDS, except that IDJ injection induced more redness 30min after saline solution. No systemic SolAE was deemed related to DebioJect™ and classical needles. No AE was deemed related to DebioJect™. No Serious Adverse Event (SAE) was reported during the study. At the end of the study all participants were considered immunized against rabies and no significant difference in humoral response was observed between the 3 studied routes.


Assuntos
Vacina Antirrábica/administração & dosagem , Vacina Antirrábica/imunologia , Raiva/prevenção & controle , Vacinação , Adolescente , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Feminino , Voluntários Saudáveis , Humanos , Injeções Intradérmicas , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Vacina Antirrábica/efeitos adversos , Vacinação/efeitos adversos , Vacinação/métodos , Adulto Jovem
4.
Neurotox Res ; 31(2): 245-258, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27796937

RESUMO

Toxins produced by cyanobacteria and dinoflagellates have increasingly become a public health concern due to their degenerative effects on mammalian tissue and cells. In particular, emerging evidence has called attention to the neurodegenerative effects of the cyanobacterial toxin ß-N-methylamino-L-alanine (BMAA). Other toxins such as the neurotoxins saxitoxin and ciguatoxin, as well as the hepatotoxic microcystin, have been previously shown to have a range of effects upon the nervous system. However, the capacity of these toxins to cause neurodegeneration in human cells has not, to our knowledge, been previously investigated. This study aimed to examine the cytotoxic effects of BMAA, microcystin-LR (MC-LR), saxitoxin (STX) and ciguatoxin (CTX-1B) on primary adult human astrocytes. We also demonstrated that α-lipoate attenuated MC-LR toxicity in primary astrocytes and characterised changes in gene expression which could potentially be caused by these toxins in primary astrocytes. Herein, we are the first to show that all of these toxins are capable of causing physiological changes consistent with neurodegeneration in glial cells, via oxidative stress and excitotoxicity, leading to a reduction in cell proliferation culminating in cell death. In addition, MC-LR toxicity was reduced significantly in astrocytes-treated α-lipoic acid. While there were no significant changes in gene expression, many of the probes that were altered were associated with neurodegenerative disease pathogenesis. Overall, this is important in advancing our current understanding of the mechanism of toxicity of MC-LR on human brain function in vitro, particularly in the context of neurodegeneration.


Assuntos
Diamino Aminoácidos/toxicidade , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Ciguatoxinas/toxicidade , Microcistinas/toxicidade , Saxitoxina/toxicidade , Cálcio/metabolismo , Proliferação de Células/efeitos dos fármacos , Toxinas de Cianobactérias , Expressão Gênica/efeitos dos fármacos , Humanos , L-Lactato Desidrogenase/metabolismo , Toxinas Marinhas , Microcistinas/antagonistas & inibidores , Degeneração Neural/induzido quimicamente , Cultura Primária de Células , Espécies Reativas de Oxigênio/metabolismo , Ácido Tióctico/farmacologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-23286347

RESUMO

Ciguatera fish poisoning (CFP), a disease caused by consuming fish that have accumulated ciguatoxins (CTXs) in their tissue, is regarded as the most prevalent form of intoxication in French Polynesia. Recently, the Australes, one of the least affected archipelago until the early 1980s, has shown a dramatic increase in its incidence rates in 2009 with unusual CFP cases. In the present work, potential health hazards associated with the proliferation of various marine phytoplankton species and the consumption of fish and marine invertebrates highly popular among local population were assessed in three Australes islands: Raivavae, Rurutu and Rapa. Extracts from the marine dinoflagellates Gambierdiscus, Ostreospis and mat-forming cyanobacteria as well as fish, giant clams and sea urchin samples were examined for the presence of CTXs and palytoxin (PLTX) by using the neuroblastoma cell-based assay (CBA-N2a). Cytotoxic responses observed with both standards (Pacific CTX-3C and PLTX) and targeted marine products indicate that CBA-N2a is a robust screening tool, with high sensitivity and good repeatability and reproducibility. In Rurutu and Raivavae islands, our main findings concern the presence of CTX-like compounds in giant clams and sea urchins, suggesting a second bio-accumulation route for CFP toxins in the ciguatera food chain. In Rapa, the potential CFP risk from Gambierdiscus bloom and fish was confirmed for the first time, with levels of CTXs found above the consumer advisory level of 0.01 ng Pacific CTX-1B g(-1) of flesh in three fish samples. However, despite the presence of trace level of PLTX in Ostreopsis natural assemblages of Rapa, no sign of PLTX accumulation is yet observed in tested fish samples. Because this multi-toxinic context is likely to emerge in most French Polynesian islands, CBA-N2a shows great potential for future applications in the algal- and toxin-based field monitoring programmes currently on hand locally.


Assuntos
Ciguatera/patologia , Ciguatoxinas/análise , Neuroblastoma/patologia , Alimentos Marinhos/análise , Linhagem Celular Tumoral , Humanos , Polinésia , Reprodutibilidade dos Testes
6.
J Ethnopharmacol ; 143(1): 33-40, 2012 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-22706150

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Senescent leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae) are traditionally used in the Pacific region to treat Ciguatera Fish Poisoning. This plant contains rosmarinic acid that is known for its multiple biological activities. In the present study, H. foertherianum aqueous extract, rosmarinic acid and its derivatives were evaluated for their capacity to reduce the effect of ciguatoxins. MATERIALS AND METHODS: Aqueous extract of H. foertherianum leaves was prepared and studied for its effects against a Pacific ciguatoxin (P-CTX-1B) in the neuroblastoma cell assay and the receptor binding assay. Rosmarinic acid and six derivatives were also evaluated by means of these bioassays. For this purpose, we have developed an improved synthetic route for caffeic acid 3,4-dihydroxy-phenethyl ester (CADPE). RESULTS: Both the aqueous extract of H. foertherianum leaves and rosmarinic acid showed inhibitory activities against a Pacific ciguatoxin in the above bioassays. Among all the molecules that were evaluated, rosmarinic acid was the most active compound. CONCLUSION: These results confirm further the potential of H. foertherianum in the treatment of Ciguatera Fish Poisoning.


Assuntos
Ciguatera/tratamento farmacológico , Ciguatoxinas/antagonistas & inibidores , Cinamatos/uso terapêutico , Depsídeos/uso terapêutico , Heliotropium/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Linhagem Celular Tumoral , Cinamatos/farmacologia , Depsídeos/farmacologia , Medicina Tradicional , Camundongos , Neuroblastoma , Ilhas do Pacífico , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta , Ácido Rosmarínico
7.
J Ethnopharmacol ; 143(1): 24-32, 2012 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-22732725

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Vitex trifolia L. (Labiatae), a widespread tree found from the Asia-Pacific to the east Africa regions is used in the traditional medicine of the Pacific islands to treat inflammatory-associated conditions. AIM OF THE STUDY: We herein evaluated its in vitro regulatory effects on the expression profile of lipopolysaccharide (LPS)-induced inflammatory genes focusing on regulation of chemokines C-X-C motif 10 (CXCL-10) and C-C motif ligand 3 (CCL-3) and cyclo-oxygenase (COX)-2. Furthermore, the plant effect on the LPS-mediated activation of Nuclear Factor kappa B (NF-κB) was also studied. MATERIALS AND METHODS: Aqueous extract of Vitex trifolia leaves was prepared and evaluated for its effect on LPS-induced stress and toxicity-related genes in RAW 264.7 macrophage cells using RT(2) Profiler Polymerase Chain Reaction (PCR) Array System. Effects of the extract on LPS-induced chemokines CCL-3 and CXCL-10, COX-2, and NF-κB p50 and p65 mRNA levels were also studied using Reverse Transcription quantitative PCR (RT-qPCR) technique. Translocation of the nuclear factor was further assessed by measuring its nuclear p65 subunit via an ELISA-based TransAM method. RESULTS: Vitex trifolia extract at 5000µg/ml exerted a significant inhibitory effect on the expression of various LPS-induced inflammatory genes in RAW 264.7 cells after 8h of incubation time. Using RT-qPCR, this anti-inflammatory effect was further confirmed by significant inhibition of CCL-3 and CXCL-10 mRNA production in LPS-stimulated RAW 264.7 cells upon treatment with 2500µg/ml of Vitex trifolia extract. Furthermore, the inhibitory activity of this plant on LPS-induced COX-2 mRNA was also observed at a concentration of 2500µg/ml in a time-dependent manner. TransAM assays showed that LPS-induced NF-κB translocation was also inhibited by Vitex trifolia extract even at a concentration of extract as low as 250µg/ml. RT-qPCR assays showed that aqueous extract of Vitex trifolia leaves had a significant inhibitory activity on LPS-induced p50 mRNA synthesis. Interestingly, however, no effect on p65 subunit mRNA expression was observed. Moreover, PCR array analysis showed that LPS-induced inflammatory and apoptosis genes under NF-κB control are also repressed by the extract. CONCLUSION: The anti-inflammatory properties of Vitex trifolia extract seem associated with inhibition of NF-κB translocation through a reduction in the expression level of NF-κB p50 but interestingly not p65 subunit mRNA. The regulatory effects of Vitex trifolia on NF-κB and consequently on inflammation mediators such as chemokines CCL-3 and CXCL-10, and COX-2 provide new evidence of its efficacy and emphasise its high potential therapeutic value. However, further in vivo experiments are still required to validate its utilization as a remedy against inflammatory diseases.


Assuntos
Anti-Inflamatórios/uso terapêutico , Mediadores da Inflamação/metabolismo , Inflamação/tratamento farmacológico , NF-kappa B/antagonistas & inibidores , Fitoterapia , Extratos Vegetais/uso terapêutico , Vitex , Animais , Anti-Inflamatórios/farmacologia , Transporte Biológico/efeitos dos fármacos , Quimiocina CCL3/genética , Quimiocina CCL3/metabolismo , Quimiocina CXCL10/genética , Quimiocina CXCL10/metabolismo , Quimiocinas/genética , Quimiocinas/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase 2/farmacologia , Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Expressão Gênica/efeitos dos fármacos , Inflamação/genética , Inflamação/metabolismo , Mediadores da Inflamação/antagonistas & inibidores , Lipopolissacarídeos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , NF-kappa B/genética , Subunidade p50 de NF-kappa B/antagonistas & inibidores , Subunidade p50 de NF-kappa B/genética , Extratos Vegetais/farmacologia , RNA Mensageiro/metabolismo , Fator de Transcrição RelA/antagonistas & inibidores , Fator de Transcrição RelA/genética
8.
J Phycol ; 48(2): 275-84, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27009717

RESUMO

Marine benthic cyanobacteria in tropical areas have recently been associated with several human poisoning events. To enhance the characterization of these microorganisms and their potential toxicity, benthic cyanobacterial communities were sampled in the lagoons of two islands (Raivavae and Rurutu) located in French Polynesia where human poisoning events by seafood had been reported. The morphological appearance of the mats was used to identify four types of cyanobacterial mat. By a 16S rRNA sequencing approach, it appeared that these mats were usually dominated by a restricted number of operational taxonomic units (OTUs), which were closely related to Leptolyngbya, Oscillatoria, Hydrocoleum, and Anabaena sequences, as previously reported in other tropical lagoons. Interestingly, we determined that these dominant filamentous OTUs were associated in the mats with other cyanobacteria, including unicellular species. By using a population genetic approach based on the sequencing of the internally transcribed spacer (ITS) of the rRNA operon, we found a very restricted genetic diversity in the most common OTU, which displayed a high sequence similarity with Leptolyngbya sp. In addition, there was no geographic differentiation at various spatial scales in the distribution of the different genotypes, suggesting that this species is able to spread over large distances. Finally, PCR screening of genes involved in the biosynthesis of known cyanotoxins revealed the presence of the saxitoxin gene (stxG) in two mats containing a mix of filamentous and unicellular cyanobacterial species.

9.
Mar Drugs ; 9(4): 543-560, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21731549

RESUMO

Marine pelagic diazotrophic cyanobacteria of the genus Trichodesmium (Oscillatoriales) are widespread throughout the tropics and subtropics, and are particularly common in the waters of New Caledonia. Blooms of Trichodesmium are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain several types of paralyzing toxins. The toxicity of water-soluble extracts of Trichodesmium spp. were analyzed by mouse bioassay and Neuroblastoma assay and their toxic compounds characterized using liquid chromatography coupled with tandem mass spectrometry techniques. Here, we report the first identification of palytoxin and one of its derivatives, 42-hydroxy-palytoxin, in field samples of Trichodesmium collected in the New Caledonian lagoon. The possible role played by Trichodesmium blooms in the development of clupeotoxism, this human intoxication following the ingestion of plankton-eating fish and classically associated with Ostreopsis blooms, is also discussed.


Assuntos
Acrilamidas/toxicidade , Venenos de Cnidários/toxicidade , Cianobactérias/química , Piranos/toxicidade , Acrilamidas/isolamento & purificação , Animais , Bioensaio/métodos , Linhagem Celular Tumoral , Cromatografia Líquida , Venenos de Cnidários/isolamento & purificação , Feminino , Humanos , Masculino , Camundongos , Neuroblastoma/patologia , Piranos/isolamento & purificação , Espectrometria de Massas em Tandem , Testes de Toxicidade
10.
Phytother Res ; 25(7): 947-58, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21287650

RESUMO

Ciguatera fish poisoning (CFP) is an illness caused by eating tropical coral fish contaminated with ciguatoxins (CTXs). The clinical management of patients with CFP is generally supportive and symptomatic in nature as no antidote exists. Of the many drugs prescribed, several have been claimed to be efficient in small, uncontrolled studies, but the outcomes of treatments with these medicines are often contradictory. In New Caledonia, traditional remedies are commonly employed in the treatment of CFP and of the 90 plant species catalogued as useful in CFP, the most popular herbal remedy by far is a decoction prepared from the leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae). Other important plants used in the treatment of CFP include Euphorbia hirta L. (Euphorbiaceae) and Vitex L. sp. (Lamiaceae). This review focuses on the evidence for efficacy of these species and pharmacological studies which support their use. Other plants used in CFP and the conventional treatment of CFP are also discussed briefly.


Assuntos
Ciguatera/tratamento farmacológico , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Ciguatoxinas/toxicidade , Humanos , Estrutura Molecular , Nova Caledônia , Plantas Medicinais/química , Vanuatu
11.
Mar Pollut Bull ; 61(7-12): 360-6, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20638088

RESUMO

Marine pelagic cyanobacteria Trichodesmium are widespread in the New Caledonia lagoon. Blooms of these Oscillatoriales are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain certain types of paralysing toxins. In the present study, toxicity experiments were conducted on lipid- and water-soluble extracts of freeze-dried samples of these cyanobacteria. Lipid-soluble fractions revealed a ciguatoxin-like activity in both in vivo (mouse bioassay) and in vitro (mouse neuroblastoma cells assay and receptor binding assay using tritiated brevetoxin-3) assays. The water-soluble fractions tested on mice exhibited neurotoxicity with paralytic symptoms. These toxicities have also been observed with benthic filamentous cyanobacteria within the Oscillatoriales order, also collected in New Caledonia. This study provides an unprecedented evidence of the toxicity of Trichodesmium species from the New Caledonia lagoon. This survey also demonstrates the possible role of these cyanobacteria in ciguatera fish poisoning.


Assuntos
Toxinas Bacterianas/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Ciguatoxinas/toxicidade , Cianobactérias/química , Ecossistema , Toxinas Marinhas/toxicidade , Microcistinas/toxicidade , Animais , Toxinas Bacterianas/química , Toxinas Bacterianas/isolamento & purificação , Linhagem Celular Tumoral , Ciguatoxinas/isolamento & purificação , Toxinas de Cianobactérias , Feminino , Masculino , Toxinas Marinhas/química , Toxinas Marinhas/isolamento & purificação , Camundongos , Microcistinas/química , Microcistinas/isolamento & purificação , Neurotoxinas/toxicidade , Nova Caledônia , Testes de Toxicidade
13.
Toxicon ; 56(5): 829-35, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19895826

RESUMO

We report the first identification of homoanatoxin-a from benthic marine cyanobacteria (Hydrocoleum lyngbyaceum) samples collected in Lifou (Loyalty Islands, New Caledonia), where cases of giant clams (Tridacna maxima) intoxications were recorded during a severe ciguatera fish poisoning outbreak. Homoanatoxin-a was also detected in extracts of giant clams harvested in the surroundings of the contaminated area suggesting the possible link between these poisoning events and the occurrence of potentially neurotoxic Hydrocoleum.


Assuntos
Toxinas Bacterianas/análise , Bivalves/microbiologia , Compostos Bicíclicos Heterocíclicos com Pontes/análise , Ciguatera/epidemiologia , Cianobactérias/química , Animais , Toxinas Bacterianas/química , Sequência de Bases , Compostos Bicíclicos Heterocíclicos com Pontes/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Biologia Marinha , Dados de Sequência Molecular , Nova Caledônia/epidemiologia , Reação em Cadeia da Polimerase , RNA de Transferência/genética , Homologia de Sequência do Ácido Nucleico
14.
Toxicon ; 56(5): 836-41, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19646469

RESUMO

Toxic cyanobacterial blooms have been a primary concern predominantly in the plankton of freshwater bodies. Recently, however, the toxicity of benthic cyanobacteria is increasingly attracting attention of the scientific community and environmental agencies. The occurrence of toxic strains in benthic cyanobacteria is intimately linked to our understanding of the diversity and ecological responses of these organisms under field conditions. To that effect, we are engaged in combined morphotypic and genotypic characterization (polyphasic) of benthic natural populations of cyanobacteria in tropical lagoons and coral reefs, with the objective to provide a reliable reference for further comparative work. The methods of identification based on phenotypic properties and those based on molecular tools for genotypic identification are correlated. The approach is based on identifying the occurrences of cyanobacterial benthic blooms, tested for purity and analyzed by application of molecular tools. The questions addressed include the distinction between marine and freshwater taxa, between populations in geographically separate regions as well as between their potential vs. expressed toxicity.


Assuntos
Cianobactérias/classificação , Toxinas Marinhas/análise , Ciguatera/microbiologia , Cianobactérias/genética , Genótipo , Toxinas Marinhas/toxicidade
15.
Toxicon ; 56(5): 674-90, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19505491

RESUMO

Based on epidemiological data available through long-term monitoring surveys conducted by both the Public Health Directorate and the Louis Malardé Institute, ciguatera is highly endemic in French Polynesia, most notably in Raivavae (Australes) which appears as a hot spot of ciguatera with an average incidence rate of 140 cases/10,000 population for the period 2007-2008. In order to document the ciguatera risk associated with Raivavae lagoon, algal and toxin-based field monitoring programs were conducted in this island from April 2007 to May 2008. Practically, the distribution, abundance and toxicity of Gambierdiscus populations, along with the toxicity levels in 160 fish distributed within 25 distinct species, were assessed in various sampling locations. Herbivores such as Scarids (parrotfish) and Acanthurids (unicornfish) were rated as high-risk species based on receptor-binding assay toxicity data. A map of the risk stratification within the Raivavae lagoon was also produced, which indicates that locations where both natural and man-made disturbances have occurred remained the most susceptible to CFP incidents. Our findings also suggest that, locally, the traditional knowledge about ciguatera may not be scientifically complete but is functionally correct. Community education resulted in self-regulating behaviour towards avoidance of high-risk fish species and fishing locations.


Assuntos
Ciguatera/epidemiologia , Gestão de Riscos , Animais , Peixes , Humanos , Incidência , Polinésia/epidemiologia
16.
Toxicon ; 56(5): 776-84, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19520100

RESUMO

Ciguatoxins, potent marine neurotoxins responsible for ciguatera, exert their numerous damaging effects through primary binding to the voltage-sensitive sodium channels of excitable cells. Using RAW 264.7 murine macrophages, we report the first experimental study presenting evidence that P-CTX-1B (the most potent congener from the Pacific) could modulate mRNA expression of pro- and anti-inflammatory cytokines as well as of inducible nitric oxide synthase (iNOS). P-CTX-1B, unlike other less potent marine polyether toxins, P-CTX-3C and PbTx-3, induced the overexpression of interleukin (IL)-1beta, IL-6, IL-10, tumor necrosis factor-alpha and iNOS with different magnitude and kinetic profiles, as compared to bacterial lipopolysaccharide (LPS). Unlike LPS, P-CTX-1B did not modulate IL-11 expression. In this report, we provide new evidence of the P-CTX-1B iNOS- and cytokines-inducing ability and shed new light on host response to potent neurotoxins.


Assuntos
Ciguatoxinas/toxicidade , Mediadores da Inflamação/metabolismo , Macrófagos/efeitos dos fármacos , Animais , Linhagem Celular , Indução Enzimática , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , Óxido Nítrico Sintase Tipo II/biossíntese , Reação em Cadeia da Polimerase , RNA Mensageiro/genética
17.
Toxicon ; 56(5): 739-50, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19540257

RESUMO

The growth and toxin production in a clonal strain of Gambierdiscus polynesiensis, TB-92, was examined in batch culture conditions. The mean growth rate at exponential phase was (0.13+/-0.03)division day(-1). Regardless of the age of cultures, all mice injected with dichloromethanolic and methanolic extracts showed symptoms specific to ciguatoxin (CTX) and maitotoxin (MTX) bioactivity, respectively. The highest total toxicity assessed in TB-92 cultures was 10.4 x 10(-4) mouse unit cell(-1). The toxin production pattern reveals an enhanced cellular toxin content with the age of the culture. CTX- and MTX-like compounds each accounted for approx. 50% of the total toxicity of TB-92 cultures, except in aged cells where CTXs were dominant. The high ciguatoxic activity of TB-92 was further confirmed in dichloromethanolic extracts by means of the receptor-binding assay. The highest CTX level monitored at late stationary phase was (11.9+/-0.4)pg P-CTX-3C equiv cell(-1). Further HPLC and LC-MS analysis revealed the presence of five CTXs congeners in lipid-soluble extracts, i.e. CTX-3C, -3B, -4A, -4B and M-seco-CTX-3C, and of new CTX congeners. Toxin composition comparison between two G. polynesiensis strains suggests that the toxin profile is a stable characteristic in this species. G. polynesiensis clones also proved inherently more toxic than other Gambierdiscus species isolated from other geographical areas.


Assuntos
Ciguatoxinas/metabolismo , Dinoflagellida/genética , Animais , Ciguatera/induzido quimicamente , Ciguatera/fisiopatologia , Ciguatoxinas/toxicidade , Dinoflagellida/metabolismo , Camundongos
18.
Org Lett ; 11(21): 4874-7, 2009 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-19863148

RESUMO

Four new dimeric pyrrole-2-aminoimidazole alkaloids have been isolated from the Pacific marine sponges Agelas cf. mauritiana and Phakellia sp. They include the unusual C2 symmetrical benzosceptrins A (4) and B (5), which each possess a unique benzocyclobutane skeleton and nagelamides S (6) and T (7). Their structures and relative configuration were elucidated from spectroscopic data. Plausible biogenetic paths for these compounds are also proposed in this paper.


Assuntos
Agelas/química , Alcaloides/isolamento & purificação , Imidazóis/isolamento & purificação , Pirróis/isolamento & purificação , Alcaloides/química , Animais , Imidazóis/química , Biologia Marinha , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Oceano Pacífico , Pirróis/química
19.
J Ethnopharmacol ; 126(3): 427-33, 2009 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-19778597

RESUMO

AIM OF THE STUDY: Vitex trifolia L. (Labiatae) is a plant commonly employed against Ciguatera Fish Poisoning (CFP) in the Pacific region. Here, the anti-inflammatory potential of an aqueous extract of Vitex trifolia leaves was evaluated by monitoring its effects on the modulation of cytokines, the mediators of inflammation, as well as on the expression profiles of inducible nitric oxide synthase (iNOS) which produces the free radical nitric oxide (NO). MATERIALS AND METHODS: We prepared an aqueous extract from Vitex trifolia leaves and evaluated its anti-inflammatory potency by monitoring its effect on the lipopolysaccharide (LPS)-induced cytokines and iNOS mRNA over-production in RAW 264.7 macrophages using quantitative Polymerase Chain Reaction (qPCR) and Enzyme-Linked Immunosorbent Assay (ELISA) methods. RESULTS: Aqueous extract of Vitex trifolia leaves showed significant dose- and time-dependent inhibitory activity on interleukin (IL)-1 beta, IL-6 and iNOS mRNA synthesis, but slight effect on tumor necrosis factor (TNF)-alpha, all of which are involved in the inflammatory response. Moreover, the plant extract seemed to induce the LPS-dependent IL-10 anti-inflammatory cytokine. These results were further confirmed by ELISA using specific antibodies to mouse IL-6, IL-10 and TNF-alpha. CONCLUSION: The anti-inflammatory effects of Vitex trifolia could validate its utilization as a traditional remedy against CFP and emphasises its potential therapeutic value against other inflammatory diseases. Therefore, this plant is a promising candidate for further screening of its active compounds through activity-guided fractionation.


Assuntos
Anti-Inflamatórios/farmacologia , Medicina Tradicional , Extratos Vegetais/farmacologia , Vitex/química , Animais , Sequência de Bases , Linhagem Celular , Citocinas/biossíntese , Primers do DNA , Ensaio de Imunoadsorção Enzimática , Camundongos , Óxido Nítrico Sintase Tipo II/biossíntese , Ilhas do Pacífico , Folhas de Planta/química , Reação em Cadeia da Polimerase
20.
J Ethnopharmacol ; 123(3): 369-77, 2009 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-19501268

RESUMO

AIM OF THE STUDY: Ciguatera fish poisoning (CFP) is an intertropical ichthyosarcotoxism that manifests in complex assortment of symptoms in humans. Ciguatoxins (CTXs), issued from Gambierdicus spp., are causative agents of this intoxication. We have recently demonstrated that a Pacific CTX (P-CTX-1B) strongly modulated iNOS expression, leading to overproduction of nitric oxide (NO) in RAW 264.7 murine macrophage cells. NO produced in large amounts is involved in a wide range of pathophysiological processes. Many traditional remedies are commonly used in the Pacific against CFP. In this context, bioassay-guided screening was carried out to study NO inhibiting capacity of 28 selected plant extracts. MATERIALS AND METHODS: We prepared aqueous extracts of plants used in New Caledonia in the treatment of CFP and screened their NO inhibitory activity in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. RESULTS: Among 28 plants tested, Euphorbia hirta (Euphorbiaceae), Syzygium malaccense (Myrtaceae), Schinus terebenthifolius (Anacardiaceae), Punica granatum (Punicaceae), Cerbera manghas (Apocynaceae), Vitex trifolia (Labiateae) and Ximenia americana (Olacaceae) showed inhibitory activity, validating their use as traditional remedies in CFP, and the potential for use in the treatment of conditions accompanied by NO overproduction. CONCLUSION: These plants are promising candidates for further screening of their active compounds through activity-guided fractionation.


Assuntos
Ciguatera , Ciguatoxinas/metabolismo , Macrófagos/efeitos dos fármacos , Magnoliopsida , Óxido Nítrico/antagonistas & inibidores , Extratos Vegetais/farmacologia , Animais , Linhagem Celular , Ciguatera/tratamento farmacológico , Ciguatera/metabolismo , Humanos , Lipopolissacarídeos , Macrófagos/metabolismo , Medicina Tradicional , Camundongos , Óxido Nítrico/biossíntese , Extratos Vegetais/uso terapêutico , Plantas Medicinais
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