RESUMEN
Plastic materials found in the environment are expected to degrade into smaller plastic nanoparticles (NPs) posing a greater toxic risk because they sorb contaminants and pass physiological barriers. Moreover the presence and effects of NPs is difficult to tease out from the contamination background at polluted sites. The purpose of this study was to examine for the presence of polystyrene NPs in feral Mya arenaria clam population near anthropogenic sources of pollution and potential toxic effects. Polystyrene NPs were determined by a newly developed fluorescence-based and size exclusion chromatography methodologies. Clam health status was determined by following changes in air survival time, condition factor, growth, alcohol/aldehyde dehydrogenase (AADH), protein aggregation and lactate dehydrogenase (LDH). In addition, multi-elemental analysis in tissues was also determined. The results revealed that clams collected at 2 polluted sites contained elevated amounts of polystyrene-like NPs between 10 and 110 nm in size based on size exclusion chromatography. Elevated levels of AADH suggest the presence of hydroxylated products and were correlated with plastic NPs in tissues. Moreover, principal component analysis revealed that As, Ca, Cu, Sn and V were closely related to either polystyrene-like NPs in tissues or AADH activity. Although we cannot rule out other pollutants, clams contaminated by polystyrene-like NPs had lower condition, growth rate, air survival time and LDH activity. Increased metal/element contamination reported to sorb onto plastic polymers were also related to NPs in tissues. In conclusion, clams populations close to anthropogenic sources of pollution show evidence of polystyrene-like NPs contamination and could contribute to decreased clam health status.
Asunto(s)
Mya , Contaminantes Químicos del Agua , Animales , Mya/química , Mya/metabolismo , Poliestirenos/toxicidad , Microplásticos/toxicidad , Microplásticos/metabolismo , Estuarios , Canadá , Contaminantes Químicos del Agua/metabolismoRESUMEN
We report herein new nanofibers prepared from fish scale gelatine (FSG), modified polylactide (MPLA), and a natural antibacterial agent of freshwater clam (Corbicula fluminea Estefanía) shell powder (FCSP). A preparation of FSG from Mullet scales is also described. To improve the biocompatibility and antibacterial activity of the non-woven nanofibers, MPLA/FCSP was added to enhance their antibacterial properties. FSG was then combined with MPLA/FCSP using an electrospinning technique to improve the biocompatibility of the as-fabricated 100-500-nm-diameter non-woven MPLA/FCSP/FSG nanofibers. The resulting tensile properties and morphological characteristics indicated enhanced adhesion among FSG, FCSP, and MPLA in the MPLA/FCSP/FSG nanofibers, as well as improved water resistance and tensile strength, compared with the PLA/FSG nanofibers. MTT assay, cell-cycle, and apoptosis analyses showed that both PLA/FSG and MPLA/FCSP/FSG nanofibers had good biocompatibility. Increasing the FSG content in PLA/FSG and MPLA/FCSP/FSG nanofibers enhanced cell proliferation and free-radical scavenging ability, but did not affect cell viability. Quantitative analysis of bacteria inhibition revealed that FCSP imparts antibacterial activity.
Asunto(s)
Gelatina/química , Nanofibras/química , Poliésteres/química , Animales , Corbicula/química , Corbicula/microbiología , Peces/microbiología , Agua Dulce/química , Mya/química , Mya/microbiología , Nanofibras/microbiología , Poliésteres/farmacologíaRESUMEN
The soft-shell clam Mya arenaria is one of the most ancient invaders of European coasts and is present in many coastal ecosystems, yet little is known about its genetic structure in Europe. We collected 266 samples spanning a latitudinal cline from the Mediterranean to the North Sea and genotyped them at 12 microsatellite loci. In parallel, geometric morphometric analysis of shell outlines was used to test for associations between shell shape, latitude and genotype, and for a selection of shells we measured the thickness and organic content of the granular prismatic (PR), the crossed-lamellar (CL) and the complex crossed-lamellar (CCL) layers. Strong population structure was detected, with Bayesian cluster analysis identifying four groups located in the Mediterranean, Celtic Sea, along the continental coast of the North Sea and in Scotland. Multivariate analysis of shell shape uncovered a significant effect of collection site but no associations with any other variables. Shell thickness did not vary significantly with either latitude or genotype, although PR thickness and calcification were positively associated with latitude, while CCL thickness showed a negative association. Our study provides new insights into the population structure of this species and sheds light on factors influencing shell shape, thickness and microstructure.
Asunto(s)
Ecosistema , Genética de Población , Mya/anatomía & histología , Mya/genética , Animales , Europa (Continente) , Genotipo , Hemocitos , Repeticiones de Microsatélite/genética , Mya/química , Mar del Norte , EscociaRESUMEN
A microwave-assisted extraction used to extract trace triorganotin from aquatic organisms and a sensitive analytical method for the determination of ultratrace triorganotin (namely trimethyltin, triethyltin, tripropyltin and tributyltin) with capillary electrophoresis-inductively coupled plasma mass spectrometry were firstly described in this study. The extraction method is simple, effective and can be used to extract trace triorganotin in aquatic organisms within several min. The analytical method has a much lower detection limit of 0.2-0.7 ng Sn/mL for triorganotin compounds, and can be used to determine trace triorganotin in aquatic organisms directly without any derivatization and preconcentration. Using above methods, we have successfully determined trimethyltin, triethyltin, tripropyltin and tributyltin in dried Mya arenaria Linnaeus and Corbicula fluminea within 17 min with a recovery of 93-104% and a RSD (relative standard deviation, n=6) of 2-5%. Our results showed that dried M. arenaria Linnaeus contained an extremely high tributyltin of 5.1 microg Sn/g dried weight, indicating that it may be a good biomarker for the organotin pollution in ocean.
Asunto(s)
Corbicula/química , Electroforesis Capilar/métodos , Espectrometría de Masas/métodos , Mya/química , Compuestos de Trialquiltina/análisis , Contaminantes Químicos del Agua/análisis , Animales , Electroforesis Capilar/economía , Límite de Detección , Espectrometría de Masas/economía , Reproducibilidad de los Resultados , Compuestos de Trialquiltina/aislamiento & purificaciónRESUMEN
The freshwater clam is a widely-consumed shellfish and is used as a remedy for chronic hepatitis in Asia. However, its contribution to acute liver injury (ALI) remains unclear. The aim of this study is to assess the protective effects of freshwater clam extract (CE) in ALI induced by hemorrhage in rats. Rats were randomly divided into 5 groups, (1) blood loss (BL) 40%, (2) CE 150 mg/kg plus BL 40%, (3) CE 75 mg/kg plus BL 40%, (4) CE 150 mg/kg, and (5) CE 75 mg/kg groups. CE was given by femoral vein catheter in Groups 2 to 5. Initial hemorrhage was induced by withdrawing blood (loss 40% of total blood volume) from a femoral arterial catheter after CE administration in Groups 2 and 3. The levels of blood tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were measured at several time points during the experimental period. Rats were sacrificed after 48 hours, and the liver was harvested for hematoxylin and eosin (HE) stain to show liver tissue injury. The results indicated that hemorrhage significantly decreased mean arterial pressure (MAP), increased blood AST, ALT and LDH levels and induced liver injury. Pre-treatment with the CE increased MAP and IL-10 levels and decreased AST, ALT, LDH and TNF-alpha levels after hemorrhage. The HE stains showed diminished organ injury in the CE groups. In conclusion, freshwater clam extract is a potential immunomodulating agent and ameliorates acute liver injury.
Asunto(s)
Proteínas Sanguíneas/farmacología , Hemorragia/tratamiento farmacológico , Hepatopatías/tratamiento farmacológico , Mya/química , Mariscos , Extractos de Tejidos/farmacología , Enfermedad Aguda/terapia , Animales , Proteínas Sanguíneas/química , Citocinas/inmunología , Modelos Animales de Enfermedad , Hemorragia/inmunología , Humanos , Hepatopatías/inmunología , Masculino , Distribución Aleatoria , Ratas , Ratas Wistar , Extractos de Tejidos/químicaRESUMEN
The purpose of this study was to examine the impacts of anthropogenic activity on the health status of intertidal clam populations of the Saguenay Fjord and the St. Lawrence Estuary (Québec, Canada). Clams were collected during low tide at sites subject to direct contamination and at sites far from human activity. Clams were analyzed for tributyltin and dibutyltin total levels and toxic stress (glutathione S-transferase, gonadal lipid peroxidation and DNA strand breaks), immunocompetence (phagocytic activity, hemocyte count and viability), reproduction (gonado-somatic index, gamete maturation, and vitellogenin-like proteins), energy status (temperature-dependent mitochondrial electron transport, and gonad lipids), and individual status (age, condition factor, and growth index). These responses were compared against population characteristics such as live clam density, number of empty shells, and sex ratio. The results show that clam density decreased with distance from the estuary (high salinity level) to upstream of the fjord (low salinity). There was no clear relationship between the number of empty shells and distance or site quality. Clam density values corrected against distance were significantly correlated with hemocyte viability, phagocytic activity, mitochondrial electron transport (MET), DNA damage in gonad, and temperature-dependent mitochondrial electron transport activity. A canonical analysis of the various groups of biomarkers revealed that population metrics were more strongly related with immunocompetence, followed by energy status and temperature-dependent mitochondrial electron transport activity. However, toxic stress biomarkers were strongly associated with energy status and reproduction. This was further confirmed by non-linear modeling using adaptive artificial neural networks (genetic selection and back propagation learning paradigms), where the following parameters were able to predict population parameters with <20% error: gonad maturation and somatic index, MET (at 4 degrees C), gonad LPO, DNA damage, and phagocytic capacity. Intertidal clam populations were influenced by a distance gradient effect (salinity), where immunocompetence, in addition to energy status, was the strongest physiological parameter related to clam population metrics.
Asunto(s)
Mya/fisiología , Contaminación Química del Agua , Animales , Biomarcadores/análisis , Recuento de Células , Roturas del ADN , Transporte de Electrón/fisiología , Femenino , Células Germinativas/fisiología , Glutatión Transferasa/análisis , Gónadas/química , Hemocitos/fisiología , Peroxidación de Lípido , Lípidos/análisis , Masculino , Mitocondrias/metabolismo , Modelos Estadísticos , Mya/química , Compuestos Orgánicos de Estaño/análisis , Fagocitos/inmunología , Quebec , Compuestos de Trialquiltina/análisis , Vitelogeninas/análisisRESUMEN
Serotonin (5-hydroxytryptamine or 5-HT) C(10)H(12)N(2)O plays a central role in several physiological processes in marine molluscs, especially in reproduction. 5-HT acts as a neurohormone to modulate spawning, parturition and meiosis by reinitiating prophase in arrested oocytes. Preliminary experiments using 10(-5)M 5-HT dissolved in aquarium water showed that 5-HT induced spawning movements in ripe clams and in both sexes of Mya arenaria while only a few males released sperm. The occurrence of serotoninergic fibers was demonstrated by PAP immunohistochemical reaction in the gonad of both sexes during gametogenesis. In an organism infected by the trematode parasite Prosorhynchus squamatus, we showed that serotoninergic innervation completely disappeared around the gonad's follicles. Although the gonad and digestive gland are intertwined, no serotoninergic innervations were found in the digestive gland. These findings suggest, for the first time to our knowledge in the soft shell clam, that serotonin might be involved in the regulation of gametogenesis.
Asunto(s)
Mya/química , Serotonina/análisis , Animales , Gametogénesis/fisiología , Tracto Gastrointestinal/química , Gónadas/química , Gónadas/inervación , InmunohistoquímicaRESUMEN
The purpose of this study was to examine the health status and gametogenetic activity in Mya arenaria clams collected at various sites in the St. Lawrence Estuary (Quebec, Canada) and in the Odense Fjord (Denmark). Clam soft tissues were analyzed for metals/metalloids and organotin compounds to confirm their exposure to these contaminants. Their health status was assessed by a test battery of biomarkers designed to measure the early biological effects of contaminants, which include expression of defence mechanisms such as xenobiotic conjugation (glutathione S-transferase), expression of stress proteins (i.e., heme oxygenase and metallothioneins), changes in gametogenetic activity, and individual morphometric characteristics. Clam tissues were also examined for the presence of oxidative damage to lipids, formation of DNA strand breaks, and alterations in heme metabolism. The results showed that clams sampled from sites with either ferry activity or intensive boat traffic in marinas were contaminated by metals/metalloids such as Ag, Al, As, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn. The clams also contained relatively high amounts of tributyltin (TBT) in their tissues (in the ng TBT/g range for both areas), with digestive glands containing more organotins than did gonadal tissues. Moreover, clams collected from TBT-contaminated sites had higher amounts of tin-heme adducts and lower total heme in their digestive glands. Condition factor, age distribution, and sex ratio were significantly altered in clams from impacted sites in the Saguenay Fjord and accompanied by an increased male/female sex ratio. Gametogenetic activity was also negatively affected, as revealed by reductions in gonadosomatic index, maturation index, aspartate transcarbamylase activity, and vitellogenin-like proteins. The Saguenay Fjord clams displayed a complex pattern of stress responses and damage such as increased heme oxygenase activity, phase 2 conjugation enzyme activity, lipid peroxidation, and altered DNA strand breaks. The integration of biomarker response data into a biomarker index at the whole-individual level (morphometric characteristics) and for various organs (gill, digestive gland, and gonad) revealed that, relative to the control site, morphological characteristics and gonadal activity were most affected at the most contaminated site, while the effects were more pronounced in the digestive gland and gill at moderately impacted sites. We conclude that the health status of M. arenaria clams at these contaminated sites is compromised, with obvious disruption of reproductive activity.