Mussel Mytilus Galloprovincialis Lmk Research Articles

Settlement and recruitment pattern variability of the mussel Mytilus galloprovincialis Lmk. from SE Bay of Biscay (Basque Country)

The annual settlement and recruitment patterns of Mytilus galloprovincialis Lmk. were assessed using collector ropes deployed at five sites along the Basque coast inhabited by wild mussel populations. The study was carried out over two periods of ten months each in three estuarine and two coastal sites, and enabled the discovery of a potential relationship between observed primary settlement and the spawning period of wild mussel populations, shedding light on the recruitment of these populations. Primary settlers were present throughout the year with highest abundances from early summer to fall. A spatial settlement pattern was also observed, with eastern estuaries showing higher settlement rates than western ones and coastal sites showing intermediate settlement rates. These spatial and temporal settlement variations could be partially explained by seasonal fluctuations in environmental factors, such as temperature and nutrients, as well as by spawning differences observed at these estuarine and coastal sites. Some inter-annual variability of settlement and recruitment was observed, with higher settlement rates in the second studied year. This inter-annual variability was consistent with the inter-annual variability of the environmental factors. The recruitment of juvenile mussels was shown to be more determined by post-settlement processes than by initial settlement abundance. Indeed, there was a substantial loss of post-larvae during fall and winter, which was due to these post-settlement processes. Thus, it is advised that ropes, which were deployed in spring and collected in winter, to be collected earlier to avoid such losses. Little space is available (i.e., due to user conflict) on the Basque Coast. Despite these limitations, these sites, particularly Bidasoa estuary, could be suitable for future seed gathering for the mussel aquaculture industry in the Basque Country.

Variability of the reproductive cycle in estuarine and coastal populations of the mussel Mytilus galloprovincialis Lmk. from the SE Bay of Biscay (Basque Country)

Mussel commercial production depends on wild populations to obtain the seed. Therefore, any new farming initiative needs deep knowledge on reproductive cycle of native mussel populations. The reproductive cycle of Mytilus galloprovincialis Lmk. from five sites, three estuarine and two coastal, along the coast of the Basque Country were assessed using gonad index and stereology over 2 consecutive years (2010 and 2011). Sex ratios, developmental stages of gonads, as well as reserve tissue cycle were analyzed. The onset of gametogenesis was observed from winter to spring, with spawning occurring from spring till summer. A resting phase followed with an increase in reserve tissues (adipogranular cells) was observed in fall. Mussels stayed ripe during winter until favorable environmental conditions were met in spring. Differences in reproductive cycles were found among populations, and also, year-to-year variability was observed within each population. In two of the studied sites asynchrony in the timing of spawning was observed between genders. These timing differences, however, did not prevent mussels at those sites from reproducing successfully. The Bidasoa estuary points to the potential of such studied sites for becoming the main source of wild mussel spats for future expected commercial mussel farming in the Basque Country. To ensure year-to-year maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.

Genetic Diversity Analysis of the Natural Populations of Mediterranean Mussels [Mytilus galloprovincialis (Lmk.)] in Agadir Bay: Assessment of the Molecular Polymorphism and Environmental Impact

Mediterranean mussel (Mytilus galloprovincialis Lmk) has a great environmental and economic importance for Morocco. This work studies the genetic structure and impact of chemical pollution on three different marine populations of Mytilus galloprovincialis that live within Agadir bay. Three collections were made at two clean sites (Cape Ghir and Cape Aglou) and at an impacted site exposed to intense boating and industrial activities (Anza). A 300-bp portion of the mitochondrial DNA coding-region Cytochrome C Oxidase subunit 1 (COI) was studied by polymerase chain reaction (PCR) and DNA sequencing reactions to assess and evaluate amounts of polymorphism in each site. Genetic analysis using COI for 64 individuals showed no significant differentiation between the three subpopulations. AMOVA demonstrated that only 2.83% of variation exists between populations. Besides the genetic evidence presented herein, mussel’s adaptation mechanisms and strategies to marine pollution are also discussed.

Cytotoxic effect of palytoxin on mussel

Palytoxin is a large and complex polyhydroxylated molecule with potent neurotoxic activity. Dinoflagellates from the Ostreopsis genera were demonstrated to be producers of this compound and analogues. Even though initially palytoxin appearance was restricted to tropical areas, the recent occurrence of Ostreopsis outbreaks in Mediterranean Sea point to a worldwide dissemination probably related to climatic change. Those dinoflagellates can bioaccumulate in shellfish, especially in filter-feeding mollusks and have been involved in damaging effects in seafood or human toxic outbreaks. The present study describes palytoxins effect on metabolic activity of mantle and hepatopancreas cells from the mussel Mytilus galloprovincialis Lmk. Our results indicate that palytoxin is highly cytotoxic to mussel cells; unlike it happens with other toxins more common in European coasts such as okadaic acid and azaspiracid. These findings have a special significance for the marine environment and aquiculture since they are evidence for the ability of palytoxin to affect the integrity of bivalve mollusks that are not adapted to the presence of this toxin.

The Ca2+-independent PKC (p105) mediates the PMA-activation of marine mussel hemocytes and the Ca2+-dependent PKC (p60) does not intervene

Previous works revealed the presence of a Ca(2+)-dependent protein kinase (p60) and a Ca(2+)-independent protein kinase (p105) in the mantle tissue from the sea mussel Mytilus galloprovincialis Lmk. The expression of both isoforms shows a balance between cytosolic and membrane fractions in mantle, gills, and hepatopancreas, whereas, in hemocytes, their expression is mainly cytosolic, as happens in muscle tissues with p60 alone. Both enzymatic forms contain phosphorylated serines, and no phosphorylation was detected in tyrosines. Only the form p105 mediates the PMA-induced activation of the hemocytes of M. galloprovincialis, and it does so by a process of down-regulation. The form p60 does not respond to the presence of the phorbol ester, suggesting structural differences related to the binding sites of the diacylglycerol.

Effects of storage temperature on oxygen depletion in intra-valve water and survival of the Mediterranean mussel Mytilus galloprovincialis Lmk

Summary Mussels are commonly air-stored during transportation and as a result suffer from anoxia. In this study, storage temperature effects on the viability and characteristics of the released intra-valve water of mussels were examined. Mussels kept at 20°C released all of their intra-valve water within approximately 60 h and died within 4 days; oxygen concentration in the intra-valve water dropped below the detectable level. In contrast, mussels kept at 0 and 5°C released 8.8% and 12% of their intra-valve water, respectively. The oxygen concentration in this water remained stable at about 3–4 mg L−1 until hour 72 of exposure to air and all mussels survived (5°C). Mussels immersed in seawater over-saturated with oxygen (35 mg L−1) did not show any uptake of the surplus oxygen into their intra-valve water.

In hemocytes from Mytilus galloprovincialis Lmk., treatment with corticotropin or growth factors conditions catecholamine release

The cells in charge of the innate immune response in the sea mussel Mytilus galloprovincialis Lmk. are the hemocytes, which have the capacity to release catecholamines when subjected to stressing conditions. Hemocytes were kept in culture before stimulation. That is, their behaviour was not studied immediately after extraction from the mollusc, as happens in most studies. This avoids the interference and variability caused by the conditions in which mussels may be when collected. This work describes the great variability found in the pattern of catecholamine release when the hemocytes are stimulated with either corticotropins or growth factors. Dopamine, adrenaline and noradrenaline release differs with each of the inducers assayed, with stimulation time and with the season of hemocyte collection. One of the results presented is particularly remarkable; such is the great amount of adrenaline and noradrenaline released to the medium when the hemocytes obtained in summer are stimulated with transforming growth factor-β1 (TGF-β1) for 60 min.

Effect of thermal stress on protein expression in the mussel Mytilus galloprovincialis Lmk

The exposure of organisms to stressing agents may affect the level and pattern of protein expression. Certain proteins with an important role in protein homeostasis and in the tolerance to stress, known as stress proteins, are especially affected. Different tissues and cells show a range of sensitivities to stress, depending on the habitat to which organisms have adapted. The response of different tissues and cells from the mussel Mytilus galloprovincialis Lmk. to heat shock has been studied in this work using different exposure times and temperatures. During the assays, protein expression was observed to vary depending on the tissue studied, the temperature or the exposure time used. But maybe the most prominent thing is the different response obtained from the cultured haemocytes and those freshly obtained from stressed mussels, which makes us think that the extraction procedure is the main cause of the response of non-cultured cells, although the haemolymph may contain components that modulate haemocyte response.

Fast, clean, low-cost screening of cadmium and lead in the mussel Mytilus galloprovincialis Lmk. by visible spectroscopy and partial least squares regression

The potential of visible (VIS) spectroscopy for screening cadmium and lead contents in the mussel Mytilus galloprovincialis Lmk. was assessed. The spectra of the samples were recorded (400–700 nm). The Cd and Pb contents were determined by graphite furnace atomic absorption spectroscopy, and were regressed against different spectral transformations by modified partial least square (PLSm) regression. Coefficients of determination in the cross-validation (Cd = 0.95; Pb = 0.77) were indicative of equations with excellent and good quantitative information, respectively. The standard deviation to standard error of cross-validation ratio (Cd = 4.43; Pb = 2.10) showed sufficient predictive accuracy for the equations to be used for screening purposes. PLSm loading plots corresponding to the first terms of the equations showed that chromophores influenced them significantly. This pioneering use of the VIS spectrum to predict Cd and Pb in mussels represents an important saving in time and cost of analysis in comparison to other methods.

Seasonal variations in haemocyte response in the mussel Mytilus galloprovincialis Lmk

In the marine mussel Mytilus galloprovincialis Lmk., the cells in charge of the immune response are the haemocytes. This work focused on the response capacity of these cells throughout the year, as significant differences between summer and winter months had been detected. The haemocytes were kept in culture for three days in order to obtain certain uniformity in cell state. Their response to inducers such as lipopolysaccharide (LPS) and interleukin-2 (IL-2) was then observed to differ significantly if collected either in summer or in winter. These differences appeared in nearly all the parameters assessed: expression of molecules binding monoclonal antibodies anti α chain of the receptor of IL-2 (anti-IL-2Rα MoAb), production of nitric oxide (NO) and catecholamines and expression of a novel protein kinase C (nPKC) purified from mussel and termed p105.

In vitro effects of LPS, IL-2, PDGF and CRF on haemocytes of Mytilus galloprovincialis Lmk.

The cells in charge of the innate immune response in the marine mussel Mytilus galloprovincialis Lmk. are the haemocytes. These cells respond in different ways to agents such as lipopolysaccharide (LPS), interleukin-2 (IL-2), platelet-derived growth factor (PDGF) and corticotropin releasing factor (CRF). After stimulation of the haemocytes, the expression of molecules reactive with monoclonal antibodies raised to the α chain of the IL-2 receptor, present in their membrane, differed depending on the agent used. The same happened with regard to the levels of dopamine, adrenaline and noradrenaline released to the medium by the haemocytes. It should also be noted that no catecholamine release was detected and the level of expression of IL-2R α showed no significant variation in cultured cells that had not been treated with inducers. These facts would indicate that most haemocytes were in the same starting condition at the moment that the stimulation was performed. Therefore, cultured haemocytes can be a highly reliable model in the study of the innate immune system.

Nitric oxide release by hemocytes of the mussel Mytilus galloprovincialis Lmk was provoked by interleukin-2 but not by lipopolysaccharide

As other marine and land mollusks, mussels have special cells in charge of the immune function called hemocytes. The activation of these cells leads to a series of events that end up in phagocytosis and in secretion of digestive enzymes that eliminate the pathogen. The production of nitric oxide is among the early activation processes. Contrary to what happens in cells of vertebrates and of other species of mollusks, in hemocytes of Mytilus galloprovincialis, LPS did not induce secretion of NO to the medium. However, human IL-2 provoked an important increase in NO production. The maximal synthesis of NO was detected after the hemocytes were incubated with the cytokine for 24 h. In both stimulated and non-stimulated cells, Western blotting showed the presence of a protein of 130 kDa, recognized by anti-mouse iNOS. Therefore, the higher production of NO can only be explained as a direct action of some effector upon the nitric oxide synthetase. NO production decreased by the action of H-89, a powerful inhibitor of the cAMP-dependent protein kinase (PKA). This suggests the involvement of PKA in the pathway of NO synthesis.

Implication of adenosine 3',5'-cyclic monophosphate, guanosine 3',5'-cyclic monophosphate, adenosine 5'-mono-, di-, and triphosphate and fructose-2,6-bisphosphate in the regulation of the glycolytic pathway in relation to the gametogenic cycle in the mussel mytilus galloprovincialis Lmk.

The changes in the contents of cyclic AMP, cyclic GMP, ATP, ADP, AMP and fructose-2,6-bisphosphate that occur in the mantle tissue of the mussel Mytilus galloprovincialis Lmk were analysed with regard to the annual gametogenic cycle. Throughout 2 years, the lowest contents of AMP, ADP and ATP were detected during late winter-spring, whereas the maximum appeared in the autumn months. During the second year, fructose-2,6-bisphosphate and cAMP showed a very similar behaviour. The levels of both compounds rose throughout the year until a maximum in September. Their behaviour was also similar to that observed during the first year, but displaced in time. Both in 1998 and in 1999, the highest level of cGMP was detected during the spring-summer months. The results obtained suggest that the glycolytic pathway, with regard to the breeding cycle, might be regulated by fructose-2,6-bisphosphate and cyclic AMP through the activation of 6-phosphofructo-1-kinase, which is the main regulating enzyme of the glycolysis in mantle of M. galloprovincialis.

Biosynthesis and role in osmoregulation of glycine-betaine in the Mediterranean mussel Mytilus galloprovincialis LMK.

Quaternary bases, for example glycine-betaine, are difficult to quantify in biological materials because of a lack of specifity. However, nuclear magnetic resonance (NMR) can determine quaternary bases even in the presence of high water concentrations. Using NMR concentrations of glycine-betaine, the posterior adductor muscle of the Mediterranean mussel Mytilus galloprovincialis were measured up to 256 μmole/g dry weight. These concentrations were related to external salinity concentrations. The biosynthesis of glycine-betaine was demonstrated in M. galloprovincialis from the precursor 14C choline.

Interactive effects of benzo(a)pyrene and cadmium and effects of di(2-ethylhexyl) phthalate on antioxidant and peroxisomal enzymes and peroxisomal volume density in the digestive gland of mussel Mytilus galloprovincialis Lmk

Exposure of marine animals to certain organic and metal pollutants is thought to enhance reactive oxygen species (ROS) production with concomitant alterations of antioxidant defence mechanisms. Some of these organic pollutants cause peroxisome proliferation, a process resulting also in possible enhanced production of ROS. The aim of this study was to investigate the effects of two organic xenobiotics, benzo(a)pyrene (B(a)P) and di(2-ethylhexyl)phthalate (DEHP), as well as the effects of cadmium (Cd), on antioxidant and peroxisomal enzymes and on peroxisomal volume density in the digestive gland of mussel, Mytilus galloprovincialis Lmk., experimentally exposed for 21 days. Special attention was paid to the interactive effects of organic and metal compounds by exposing one group of mussels to a mixture of B(a)P and Cd. Exposure of mussels to Cd caused a decrease in superoxide dismutase (SOD) activity, in Mn-SOD protein levels and in volume density of peroxisomes. B(a)P exposure significantly increased catalase and glutathione peroxidase (GPX) and inhibited Mn-SOD after 21 days of exposure. B(a)P also caused a slight increase in acyl-CoA oxidase (AOX) activity and peroxisomal volume density after 21 days of exposure. Cd tended to inhibit changes provoked by B(a)P, indicating that responses to organic xenobiotics can be modulated by concomitant exposure to metal contaminants. Exposure to DEHP increased catalase and AOX and inhibited SOD activity and Mn-SOD protein levels. In conclusion, peroxisome proliferation, measured as an increase of the peroxisomal enzymes catalase and AOX (up to 1.53-fold for AOX), is a specific response to organic contaminants such as B(a)P and DEHP, whereas Cd does not cause peroxisome proliferation. Thus, peroxisome proliferation may be a specific biomarker of organic pollutants in mussels. Both organic and metal pollutants inhibited SOD activity and protein levels (up to 0.21-fold for Mn-SOD protein levels), the latter offering potential as general marker of pollution.

Implication of guanosine 3',5'-cyclic monophosphate, adenosine 3',5'-cyclic monophosphate, adenosine 5'-mono-, di- and triphosphate and fructose-2,6-bisphosphate in the regulation of the glycolytic pathway in hypoxic/anoxic mussel, Mytilus galloprovincialis.

The change in the content of cyclic GMP, cyclic AMP, ATP, ADP, AMP and fructose-2,6-bisphosphate that occurred in the mantle of the mussel Mytilus galloprovincialis Lmk when specimens of this mollusk were subjected to a hypoxia/anoxia situation were assessed. After the early 24 h in anaerobiosis, a clear decrease was observed in the ATP content, which remained close to that value for the rest of the time. AMP content doubled during the early 24 h in anaerobiosis and, from that time on, it remained close to that value. Fructose-2,6-bisphoshate and cyclic GMP showed a similar behavior. The levels of these compounds rose significantly during the early hours in anaerobiosis, and then fell to values similar to those of aerobiosis, remaining constant for the rest of the time. Neither ADP nor cAMP showed significant variations.

Two-dimensional gel electrophoresis of Mytilus galloprovincialis differences in protein expression between intertidal and cultured mussels

Two-dimensional gel electrophoresis (2-DE) is a unique method of large-scale protein characterisation, and is a powerful approach in the study of protein expression. In the present work, the experimental conditions for 2-DE of foot proteins from the mussel Mytilus galloprovincialis Lmk were established; the technique was performed with intertidal and cultured mussels using Melanie 3 software for data analysis. This powerful technique enabled the visualisation of a total of 750 protein spots consistently expressed in the foot. The intensity of 92 selected spots was compared between intertidal and cultured mussels, and statistically significant differences were detected in the expres- sion of 45 (48.9%) of the 92 proteins analysed. In 31 of these proteins, intensity was higher in the cul- tured stock than in the intertidal mussels, while in 14 proteins spot intensity was higher in the latter. Using mass spectrometry (MS) combined with sequence database searching, 6 of the most prominent differentially expressed proteins were analysed. Of these, 1 was identified as being Heat-shock Pro- tein 70, and 2 were shown to be cytoskeleton-associated proteins, myosin and actin. Heat-shock Protein 70, which is known to be involved in cellular transport and chaperoning and associated with stress situations, was more highly expressed in intertidal mussels living in littoral areas than in cultured mussels. These findings are discussed in connection with the molecular changes involved in the adaptation of mussels to different ecological conditions.

Measurement of Adenosine 3′,5′-Cyclic Monophosphate and Guanosine 3′,5′-Cyclic Monophosphate in Mussel (Mytilus galloprovincialis Lmk.) by High-Performance Liquid Chromatography with Diode Array Detection

Two fast and sensitive methods for the determination of cAMP and cGMP levels in mantle tissue of the sea mussel Mytilus galloprovincialis Lmk. are described. Both methods use ion-pair high-performance liquid chromatography with diode array detection. The use of the diode array detector permitted the simultaneous detection of the absorbance at two different wavelengths and the obtaining of the UV absorption spectrum for each detected peak, confirming peak purity and identity. Method precision was good. The detection limit for both nucleotides was 2.5 pmol (signal-to-noise ratio = 4 at 254 nm). Previous to the injection onto the chromatograph, both nucleotides were purified by precipitation of the adenine and guanine 5′-ribonucleotides with ZnSO4–Na2CO3. The supernatant obtained was subsequently passed over an anion-exchange column (AG l-X8 formate form resin). Early results seem to indicate that there is a seasonal variation in the contents of both cyclic nucleotides in mantle tissue. Such variation is probably related to the annual gametogenic cycle.

Energy balance of mussels Mytilus galloprovincialis:the effect of length and age

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 199:149-158 (2000) - doi:10.3354/meps199149 Energy balance of mussels Mytilus galloprovincialis: the effect of length and age Alejandro Pérez Camacho1,*, Uxio Labarta2, Enrique Navarro3 1Instituto Español de Oceanografía, Centro Costero, Aptdo. 130, 15001 La Coruña, Spain 2CSIC, Instituto de Investigaciones Marinas, c/Eduardo Cabello 6, 36208 Vigo, Spain 3Dpto de Biología Animal y Genética, Universidad del País Vasco. Aptdo. 644, 48080 Bilbao, Spain *E-mail: alejandro.perez@co.ieo.es ABSTRACT: Clearance and ingestion rates, absorption efficiencies and respiration rates were measured in mussels Mytilus galloprovincialis Lmk of different lengths (53 to 89 mm) and age (10 to 24 mo) from cultivation rafts in the Ría de Arosa (Galicia, Spain). The experiments were carried out either in the laboratory, using monoalgal food (Isochrysis galbana) with an organic content of 91%, or under natural conditions of food availability in cultivation rafts with seston, the organic content of which ranged from 33 to 69%. Food concentrations ranged from 0.57 to 1.00 mg l-1 of total particulate matter (TPM), a load which is below the threshold for the production of pseudofaeces in Mytilus. These experiments proved that the ingestion rate (IR = mg TPM h-1) of food increases with the size of the mussel (measured as g of soft-tissue dry weight [DW]) according to the power equation IR = 12.661DW0.619, this model accounting for over 90% of the variance of the IR. Behavioural patterns that tended to maintain constant IR regardless of the density of the food were observed. Absorption efficiency (AE) is positively related to the organic content (OC) of the food according to the following hyperbolic equation: AE = 1.015 - 0.163(1/OC) (r = 0.940). AE is independent of mussel size for most of the size range used in this study, but there is a critical length around 85 mm, above which there is a noticeable decrease of AE. Metabolic expenditure, measured in terms of oxygen consumption standarized per unit of dry weight of flesh, tends to increase with the age of the mussel. The results obtained led to the conclusion that physiological traits such as the regulation of ingestion or differences in AE between groups do not explain the differences in growth between mussels of the same age. These differences must therefore be due to the limited food and space available as a result of the large numbers of mussels on the cultivation rafts and the agglomeration of mussels on the cultivation ropes. KEY WORDS: Mytilus · Ingestion rate · Respiration · Absorption efficiency · Food quality Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 199. Publication date: June 26, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Seasonal variation of xanthine oxidoreductase activity in the digestive gland cells of the mussel Mytilus galloprovincialis: A biochemical, histochemical and immunochemical study

The activity and the tissue distribution of the oxygen radical producing enzyme xanthine oxidoreductase (XOR) were measured in the digestive gland of the common marine mussel Mytilus galloprovincialis Lmk along an annual cycle. No xanthine oxidase (XOX) activity could be measured, the enzyme only displaying xanthine dehydrogenase (XDH) activity in all the cases. This is interpreted as a mechanism to avoid the harmful effects of the oxygen radicals that would be produced by XOX during periods following anoxic conditions at low tide. The highest XDH activities coincided with the late spring/early summer months, the activity maxima being recorded from May to July. Histochemically XOR activity was very pronounced in duct and stomach epithelial cells as well as in the surrounding connective tissue and hemolymph vessels, the activity increasing towards the summer months. These seasonal variations in XDH or XOR activities are possibly linked to hormonal changes governing the reproductive cycle and to changes in food availability. The localization of the protein in the connective tissue lining the hemolymph vessels was confirmed immunohistochemically using a polyclonal antibody against rat liver protein that cross-reacted specifically with a polypeptide of 150 kDa of molecular mass in homogenates of the digestive gland. This polypeptide was linked to cytosolic fractions isolated by differential centrifugation from mussel digestive glands. In paraffin sections the antibody labeled the digestive cells of digestive tubules, as well as the connective tissue surrounding the hemolymph vessels, gonadal follicles, digestive epithelia and certain protozoan parasites. Taken together our results suggest that in the digestive gland of bivalve molluscs XOR is involved in the metabolism of purines and in the scavenging of oxygen free radicals.