Surf Clam Research Articles

Molecular Cytogenetics in Trough Shells (Mactridae, Bivalvia): Divergent GC-Rich Heterochromatin Content.

The family Mactridae is composed of a diverse group of marine organisms, commonly known as trough shells or surf clams, which illustrate a global distribution. Although this family includes some of the most fished and cultured bivalve species, their chromosomes are poorly studied. In this work, we analyzed the chromosomes of Spisula solida, Spisula subtruncata and Mactra stultorum by means of fluorochrome staining, C-banding and fluorescent in situ hybridization using 28S ribosomal DNA (rDNA), 5S rDNA, H3 histone gene and telomeric probes. All three trough shells presented 2n = 38 chromosomes but different karyotype compositions. As happens in most bivalves, GC-rich regions were limited to the nucleolus organizing regions in Spisula solida. In contrast, many GC-rich heterochromatic bands were detected in both Spisula subtruncata and Mactra stultorum. Although the three trough shells presented single 5S rDNA and H3 histone gene clusters, their chromosomal locations differed. Regarding major rDNA clusters, while Spisula subtruncata presented a single cluster, both Spisula solida and Mactra stultorum showed two. No evidence of intercalary telomeric signals was detected in these species. The molecular cytogenetic characterization of these taxa will contribute to understanding the role played by chromosome changes in the evolution of trough shells.

Early development of undulated surf clam, Paphia undulate under elevated pCO2

Increasing atmospheric CO2 can decrease the seawater pH and carbonate ions, which may adversely affect the larval survival of calcareous animals. In this study, we simulated future atmospheric CO2 concentrations (800, 1500, 2000 and 3000μatm) and examined the effects of ocean acidification on the embryonic and larval stage of an infaunal clam Paphia undulate. Significant decrease of hatching of P. undulate was observed when the pCO2 reached 3000μatm, and larval deformation rate increased significantly when pCO2 reached 2000μatm, indicating a strong tolerance to ocean acidification compared with the embryonic development of other bivalves. The larvae cultured in 1500μatm pCO2 exhibited the fastest growth, highest survival and shortened planktonic period, which unordinary phenomenon reflected the beneficial effect of ocean acidification on P. undulate larval development. The better development of P. undulate larvae under a higher CO2 condition maybe an adaptation in response to the acidified sediment in which they live.

Effect of substrate component on the growth and survival of juvenile sunray surf clam (Mactra chinensis Philippi)

Substrate is a critical environmental factor affecting the activity of bivalves. To examine the effect of the substrate component on the growth and survival of juvenile sunray surf clam (Mactra chinensis Philippi), a series of short-term experiments were conducted using a variety of substrates with different ratios of sand to mud. The experimental group cultured without substrate showed poor survival, with all juveniles died after day 20. The juveniles cultured in mud without sand showed a lower survival rate (25.54% ± 0.40% on day 45) than those in other groups. The juveniles cultured in sand without mud, or the mixtures of sand and mud with a ratio of 1:1 and 2:1, respectively, exhibited modest survival at day 45. Maximal weight gain rate (WGR), shell length growth rate (LGR), and specific growth rate (SGR) were observed when the sand concentration was 61.97%, 77.69%, and 64.64%, respectively. As the fast growth and high survival were observed when the sand to mud ratio was 1:1 (50% sand) and 2:1 (67% sand), a sand concentration of more than 50% is optimal. The optimal concentration of sand in the substrate for rearing juvenile sunray surf clams was 67% which resulted in the fastest growth and highest survival. These results can be used to developing a nursery/farming technique of improving the yield of sunray surf clams.

Feed intake, growth, and behavioral assessment of mink fed a clam-based diet

The objective of this study was to assess the acceptance and safety of two species of food-grade clams, ocean quahog (Arctica islandica) and Atlantic surf clam (Spisula solidissima), for consumption by fur-farmed American mink (Neovison vison). These clams contained thiaminase that can lead to weight loss, paralysis, and death. Across 19 wk, 39 black, adult female mink divided into three groups were fed a standard chicken-based control diet, 10% clam diet, or 20% clam diet and assessed for feed consumption rates, body weights, locomotor stereotypic behavior, overall activity levels, and ability to complete a novel tunnel climbing task. The 20% clam group consumed significantly less metabolizable energy compared with the control group, but there was no significant difference in weight gain between groups. There were some inconsistent group differences in stereotypy and overall activity with all groups showing significant behavioral differences across study weeks; possibly related to ambient weather and photoperiod. There were no significant group differences in their ability to complete the tunnel task. Based on our results, no negative effect of clam consumption was observed in adult female mink, but further studies are needed to determine clam safety to both male and female mink from all life stages.

The antioxidant potential of the New Zealand surf clams

The antioxidant action of three New Zealand surf clams was evaluated for the first time. Aqueous (cd) and ethanolic extracts from Diamond shell – Crassula aequilatera, Storm shell – Mactra murchisoni, and Tua tua – Paphies donacina were studied for their antioxidant potentials using two in vitro assays. The ethanolic extracts were further fractioned into four parts; petroleum ether (pe), ethyl acetate (ea), n-butanol (nb), and the final aqueous fraction (w). Comparing among all fractions tested, the ea fraction of P. donacina showed the strongest free radical scavenging power, with a radical scavenging activity of 76.14% at 20μg/mL. The ea fraction of C. aequilatera had the highest copper reducing activity with an absorbance of 1.596 at 20μg/mL. Results from this study suggest that some bioactive compounds with significant antioxidant effects may exist in the New Zealand surf clams, and could potentially reduce oxidative stress to deliver health benefits or to produce functional foods.

In situ sampling reveals rapid uptake and depuration of polycyclic aromatic hydrocarbons by surf clams (Paphies subtriangulata) affected by the Rena oil spill

ABSTRACTTo investigate the uptake and depuration of polycyclic aromatic hydrocarbons associated with the Rena oil spill we sampled the surf clam Paphies subtriangulata at two open coast locations (6 km apart) just prior to oil coming ashore (7 October 2011), then at 1–3 week intervals for the next 4 months. Total polycyclic aromatic hydrocarbons (tPAH) increased at both sites from 1 to 96–124 µg kg−1 (wet weight) by 18 October before declining to low levels (<4 µg kg−1) by February 2012. Ongoing sampling throughout 2012–2014 included three additional sites to the north east (up to 30 km away) and a site 5 km to the south east revealing tPAH levels generally <10 µg kg−1 except in October 2013 where levels ranged between 39–45 µg kg−1 at all sites. A comparison of PAH component profiles with oil-contaminated beach sediment indicated that the high levels observed in surf clams between October–December 2011 were clearly associated with the Rena spill. However, the October 2013 peak had a PAH profile inconsistent with weathered Rena oil, suggesting an alternative source of contamination. Our results highlight the potential for P. subtriangulata as a PAH monitoring tool but recognise more study is needed to better quantify baseline levels and uptake and depuration dynamics.

Potential Association between Insulin-like Growth Factor-1 Receptor Activity and Surf Clam Spisula sachalinensis Larvae Survival

Abstract We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M di-methyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrifica-tion. After immersion into VSs and freezing, IGF-1R β-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular β-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability. Key words: Spisula sachalinensis , Surf clam, D-shaped larvae, Umbo larvae, Vitrification, IGF-1R Introduction A number of attempts to develop a cryopreservation pro-cess in mammals and aquatic organisms have been made. Al-though vitrification is appealing because of its simplicity, it faces the challenges of intra/extracellular ice formation and the toxicity of high concentrations of cryoprotective agents. Recently, methods for vitrification of fish embryos, including zebrafish (

Recovery of a Surf Clam Donax deltoides Population in Southern Australia: Successful Outcomes of Fishery‐Independent Surveys

AbstractEstimates of biomass or relative biomass are required for monitoring the recovery of depleted bivalve resources and for the management of newly exploited resources. Uncertainty around fishery catch per unit effort (CPUE) as a proxy for biomass highlights the need for fishery‐independent assessments. Following a prolonged period of decline in Australia's largest fishery for surf clam Donax deltoides, robust estimates of biomass were required to monitor recovery and to set appropriate total allowable commercial catches. Estimates of relative biomass were derived from fishery‐independent surveys (FIS) conducted cooperatively by researchers and fishers. The FIS assessed both the spatial (m to km) and temporal (months to years) dynamics of the fishery and enabled comparisons with CPUE. Concurrent size‐frequency distributions provided information on the mechanisms underlying variability in resource status across the fishery. Increasing relative biomass and complexity of size structures indicated recovery of the resource from 2009, although spatial contraction of the resource also occurred. Relative biomass from FIS provides a robust fishery performance indicator that is appropriate to the scale of the fishery and has advantages over fishery‐dependent CPUE of finer temporal and spatial resolution and consistent sampling efficiency. Performance indicators based on FIS provide improved understanding of the changes in resource status. Active engagement of fishers contributes to enhanced economic and environmental outcomes.Received December 9, 2014; accepted September 3, 2015

Widespread Natural Occurrence of Hydroxyurea in Animals.

Here we report the widespread natural occurrence of a known antibiotic and antineoplastic compound, hydroxyurea in animals from many taxonomic groups.Hydroxyurea occurs in all the organisms we have examined including invertebrates (molluscs and crustaceans), fishes from several major groups, amphibians and mammals. The species with highest concentrations was an elasmobranch (sharks, skates and rays), the little skate Leucoraja erinacea with levels up to 250 μM, high enough to have antiviral, antimicrobial and antineoplastic effects based on in vitro studies. Embryos of L. erinacea showed increasing levels of hydroxyurea with development, indicating the capacity for hydroxyurea synthesis. Certain tissues of other organisms (e.g. skin of the frog (64 μM), intestine of lobster (138 μM) gills of the surf clam (100 μM)) had levels high enough to have antiviral effects based on in vitro studies. Hydroxyurea is widely used clinically in the treatment of certain human cancers, sickle cell anemia, psoriasis, myeloproliferative diseases, and has been investigated as a potential treatment of HIV infection and its presence at high levels in tissues of elasmobranchs and other organisms suggests a novel mechanism for fighting disease that may explain the disease resistance of some groups. In light of the known production of nitric oxide from exogenously applied hydroxyurea, endogenous hydoxyurea may play a hitherto unknown role in nitric oxide dynamics.

Identification of functional genes involved in Cd(2+) response of Chinese surf clam (Mactra chinensis) through transcriptome sequencing.

The Chinese surf clam Mactra chinensis is an economically important bivalve species in the coastal waters of Liaoning and Shandong Province, China. In this study, we carried out transcriptome sequencing to develop molecular resources for M. chinensis and conducted an acute test of Cd(2+) stimulation through quantitative real-time PCR (qRT-PCR) to analyze the relative expression of six functional genes. A total of 100,839 transcripts and 56,712 unigenes were obtained from 39.9 million filtered reads and 21,305 unigenes were annotated by hitting against NCBI database. According to the results of qRT-PCR, heat shock protein 22 (Hsp22) and cytochrome P450 (CYP450(2C31)) were inhibited in the low concentration, and induced in the high concentration of Cd(2+); thioredoxin peroxidase (TPx-A) was at normal level in low concentration, but induced in high concentration of Cd(2+); glutathione peroxidase A (GPA), glutathione peroxidase 1 (GPA1) and Mn superoxide dismutase gene (MnSOD) were down-regulated when exposed to any treatment groups. Expression levels of the six functional genes following Cd(2+) exposure indicated that these genes were linked to environmental stress. Moreover, the present work enriched the molecule genetic data of M. chinensis.

Population subdivision of the surf clam Mactra chinensis in the East China Sea: Changjiang River outflow is not the sole driver.

The northwestern Pacific, characterized by unique tectonic and hydrological settings, has greatly intrigued marine phylogeographers. However, current studies mostly focus on the influence of Pleistocene isolation of sea basins in population structure of species in the region, leaving the contribution of other factors (such as freshwater outflow and environmental gradients) largely unexploited. Here we shed light on the question by investigating phylogeography of the surf clam Mactra chinensis in the East China Sea (ECS). Genetic information was acquired from 501 specimens collected from its main distribution in the region, represented by mitochondrial cytochrome oxidase I (COI) and nine polymorphic microsatellite loci. A shallow and star-like phylogeny was revealed for all COI haplotypes, indicating the origin of populations from a single refugium. Although no divergent lineages existed, population subdivision was detected in both data sets. The most striking pattern was the significant differentiation between populations north and south of a biogeographic boundary—the Changjiang Estuary, suggesting a barrier effect of the freshwater outflow to gene flow. For the northern group, substructure was revealed by COI result as one southernmost population was significant different from other ones. Clear latitude gradations in allele frequencies were revealed by microsatellite analyses, likely influenced by environmental gradient factors such as temperature. Our results demonstrate that genetic subdivision can arise for populations within the ECS despite they have a single origin, and multiple mechanisms including Changjiang River outflow, environmental gradient factors and life-history traits may act in combination in the process.

A comparison of the physiological responses, behaviour and biotransformation of paralytic shellfish poisoning toxins in a surf-clam (Paphies donacina) and the green-lipped mussel (Perna canaliculus)

The accumulation of paralytic shellfish toxins (PSTs) in bivalves is species specific. We compared the physiological responses and the toxin profiles in tissues of the burrowing surf clam, Paphies donacina, and the green-lipped mussel, Perna canaliculus, exposed to the toxic dinoflagellate Alexandrium tamarense. Bivalves were supplied with the toxic algae for 10 days, then allowed a detoxification period of 8 days. Clearance rates of mussels and clams were similar when fed either with toxic A. tamarense or non-toxic A. margalefi. Byssus production in the mussel was inhibited and exhalent siphon activity in clams was erratic following exposure to A. tamarense. There were considerable differences in the toxic profile between the dinoflagellate A. tamarense, and tissues of the mussel and the surf clam, indicating that bioconversion of the PSTs had taken place. Toxin profiles of the tissues were both species and tissue specific. Following an 8-day detoxification period, total PSTs in mussels had fallen to safe concentrations below 50µg per 100g, whereas concentrations in clams remained high, with an average value greater than 600µg STX di-HCL equivalents per 100g. The results confirmed that mussels and clams are important monitoring organisms for toxic algal blooms and can be used to minimise the health risk of PSTs to humans.

Mitochondrial phylogeography of a surf clam Mactra veneriformis in the East China Sea: Genetic homogeneity across two biogeographic boundaries

Biogeographic boundaries constraining species' distributions often generate intraspecific ‘breaks’ for those species whose ranges span them—known as the ‘biogeography-phylogeography concordance’ hypothesis. The East China Sea (ECS) in the northwestern Pacific comprises two reported boundaries: the Shandong Peninsula and the Changjiang Estuary, providing an elegant setting to test the hypothesis in marine environment. Here we investigated population structure of the surf clam Mactra veneriformis (Reeve, 1854) using 235 individuals from its major distribution in the ECS, represented by mitochondrial cytochrome oxidase I sequences. A ‘star-like’ topology with shallow divergence was revealed for all haplotypes, of which the central (also assumed ancestral) one appearing in all populations. No significant genetic structure was revealed among populations, suggesting substantial genetic homogeneity across the range. Demographic expansion was revealed for individual and overall populations, and the expansion time was estimated from 23,000 years ago. These results suggested that the M. veneriformis populations originated from an ancestral panmictic population in the ECS basin, and had experienced significant population expansion since the last glacial maximum. From a mitochondrial view, the two boundaries did not act as barriers for the phylogeography of M. veneriformis.

Two New and Two Poorly Known Species of Ancistrum (Ciliophora, Scuticociliatia, Thigmotrichida) Parasitizing Marine Molluscs from Chinese Coastal Waters of the Yellow Sea

The morphology and taxonomy of two new and two poorly known ciliate species of Ancistrum, found in the mantle cavity (mainly on gills) of marine molluscs from culture beds and pools along the Chinese coast of the Yellow Sea, were investigated using living observation and silver impregnation. Ancistrum haliotis n. sp. was isolated from the abalone Haliotis discus hannai Ino, A. crassum Fenchel, 1965 from the purple clam Saxidomus purpuratus (Sowerby), A. acutum n. sp. from the surf clam Mactra veneriformis Reeve, and A. japonicum Uyemura, 1937 from both the venus clam Cyclina sinensis (Gmelin) and from Dosinia japonica (Reeve). Ancistrum haliotis differs from its most similar relative A. mytili (Quennerstedt, 1867) by the body outline (anterior portion narrower vs. wider than the posterior portion), the macronuclear shape (broadly ellipsoidal vs. reniform or sausage-like), and by having fewer somatic kineties (28-32 vs. usually more than > 40). Ancistrum crassum is characterized by the naked area at the apical end of the cell, the relatively short buccal field occupying about two thirds of the body length, and the posterior-dorsal cone-shaped prolongation. Ancistrum acutum n. sp. and A. japonicum are almost identical in morphometry, but differ distinctly in the live morphology (anterior end pointed and posterior end rounded vs. anterior end narrowly rounded and posterior-dorsal end protruded) and ciliary pattern (all right-side kineties extend to posterior body end vs. all right-side kineties excluding somatic kinety 1 distinctly shortened posteriad, forming a glabrous zone). We neotypify Ancistrum japonicum and discuss the taxonomic status of the four species. Based on an evaluation of all nominal species of Ancistrum and Ancistrumina, we recognize nine valid species of Ancistrum and provide a tabular guide to their identification. Fenchelia Raabe, 1970 is regarded as a junior synonym of Ancistrum Maupas, 1883. We synonymize Ancistrumina nucellae Khan, 1970 with Ancistrum japonicum Uyemura, 1937 and Ancistrum edajimanum Oishi, 1978 with A. crassum Fenchel, 1965.

Productivity change and fleet restructuring after transition to individual transferable quota management

Productivity change after transition to an individual transferable quota (ITQ) management system is driven by exit of some vessels, entry of other vessels, and changes in productivity of existing vessels. Generally, it is thought that an ITQ system boosts productivity due to the exit of less productive vessels. However, ITQ management systems also create an additional barrier to entry, and more productive vessels may not be able to enter the fishery. This study constructs the Färe–Primont index to measure productivity change for the Mid-Atlantic surf clam and ocean quahog fishery over a 32 year time period, which includes both pre and post-ITQ time periods. The index is then combined with a biomass change index to arrive at a measure of biomass adjusted productivity change. Results show that when biomass changes are considered, positive productivity gains occurred throughout the time period. Further examination of contributions from entering and survivor vessels show that entering vessels had little impact on aggregate productivity, but on an individual basis, they eventually were equal in productivity to survivor vessels.

Depuration and anatomical distribution of domoic acid in the surf clam Mesodesma donacium.

In northern Chile, domoic acid (DA) has been detected in several bivalve species. In Mesodesma donacium, one of the most important commercial species for local fishermen, no information is available on depuration, or on the anatomical distribution of this toxin and its potential use as a palliative measure to minimize the consequences of ASP outbreaks. Deputation of DA is very fast in M.donacium, and can be adequately described by means of a two-compartment model. The estimated rates for the first and second compartments were 1.27d(-1) and 0.24d(-1), respectively, with a transfer rate between compartments of 0.75. Having high depuration rates protects this species from being affected by Pseudo-nitzschia blooms for an extended period of time. Taking this into account, the time in which the bivalves are unsafe for consumers is very short, and therefore the economic losses that could result by the DA outbreaks in local fisheries should be moderate. In relation to anatomical distribution, at least during the uptake phase, the toxin was evenly distributed within the soft tissues, with a total toxin burden corresponding to 27%, 32% and 41% for Digestive Gland (DG), Foot (FT) and Other Body Fractions (OBF), respectively. Since the contribution of each organ to the toxin concentration is a function of both weight contribution and toxin burden, the pattern of toxin distribution showed the following trend: "all other body fractions" (OBF)>Foot (FT)>Digestive Gland (DG). Thus, the highest concentration of DA, with a contribution close to 72%, corresponds to the edible tissues (OBF+FT), while the DG (non-edible tissue) only contributes the remaining 28%. Consequently, in view of the anatomical distribution of domoic acid in M.donacium, the elimination of the digestive gland does not substantially reduce the toxicity of the final product and therefore selective evisceration would not improve their quality for human consumption.

Performance Characteristics of AOAC Method 2005.06 for the Determination of Paralytic Shellfish Toxins in Manila Clams, European Otter Clams, Grooved Carpet Shell Clams, Surf Clams, and Processed King Scallops.

An approach was developed for the verification of method performance of the AOAC 2005.06 LC-fluorescence detector (FLD) method for determination of paralytic shellfish poisoning (PSP) toxins in bivalve shellfish. This was developed following advice published by the Analytical Laboratory Accreditation Criteria Committee and applied to shellfish species that had not been previously subjected to a full single-laboratory validation scheme. The refined approach was developed following the need to assess performance in a number of shellfish species infrequently monitored through the UK statutory monitoring program, while reducing the impact and cost of the studies, most notably in terms of the use of valuable reference standards. The species assessed were manila clams (Ruditapes philippinarum), European otter clams (Lutraria lutraria), grooved carpet shell clams (R. decussatus), surf clams (Spisula solida), and king scallops (Pecten maximus) presented as adductor only or adductor plus roe. The method was assessed for sensitivity in terms of LOD and LOQ, toxin recovery, and method precision in each species. It incorporated the PSP toxins deemed toxic and/or prevalent in UK samples and commercially available as certified reference standards. The toxins studied included GTX1-5, dcSTX, STX, C1&2, and NEO. The toxins dcGTX2&3 were included for surf clams due to the prevalence of these toxins in this species as a result of toxin decarbamoylation. Method performance targets were met for each of the characteristics investigated. Consequently, the method was deemed fit for purpose for the screening and quantification of these clam and scallop species for PSP toxins by AOAC Method 2005.06 LC-FLD.

Embryonic and larval development of the New Zealand bivalvePaphies ventricosaGray, 1843 (Veneroida: Mesodesmatidae) at a range of temperatures

Paphies ventricosa is a large (up to 150 mm shell length) surf clam endemic to New Zealand, with a geographically patchy distribution. Using scanning electron microscopy and light microscopy, its fertilization, embryonic and larval development were observed at three culturing temperatures (12, 16 and 20 8C). The progress of development follows that previously described for the family Mesodesmatidae, with P. ventricosa having a small egg (63– 70 mm), with a 83 –102 mm trochophore stage observed at 15 h, and a 100 mm D-veliger larva observed at 22 h at 12 and 168C, and 37 h at 20 8C. At 20 8C, the pediveliger larval stage was reached by 31 d. While the morphology of the embryonic and larval stages of P. ventricosa is typical for bivalves, we show that in this species the shell field invagination occurs in the gastrula stage and that the expansion of the dorsal shell field occurs during gastrulation, with the early trochophore having a well-developed shell field that has a clearly defined axial line between the two shell lobes. The growth of P. ventricosa larvae cultured at 12, 16 or 20 8C over 39, 33 and 31 d respectively, was faster at warmer temperatures. Using the temperature quotient Q10 at day 27 to quantify the response to temperature, values of Q10 ¼ 1.82 for the range 12 –16 8C and Q10 ¼ 2.33 for the range 16–20 8C were calculated. Larval shape was not temperature dependent, suggesting that the smaller larvae found at colder temperatures reflect a slowing of larval development, rather than physiological damage by temperature resulting in abnormal larval development.

Profiles of paralytic shellfish toxins in bivalves of low and elevated toxicities following exposure to Gymnodinium catenatum blooms in Portuguese estuarine and coastal waters

Profiles of paralytic shellfish toxins (PSTs) were examined in 405 composite samples of Mytilus spp., Cerastoderma edule, Donax trunculus and Spisula solida collected between 2007 and 2012 from natural production areas in two estuaries (Aveiro and Mondego), two coastal lagoons (Óbidos and Formosa), and three open coastal areas (Aguda, Comporta and Culatra). Toxin concentrations were obtained from the biotoxin monitoring programme database. Episodes of PST toxicity in Portugal have been associated with Gymnodinium catenatum blooms. Toxin profiles for each species showed no trend over the surveyed years. In general, profiles differ only slightly among areas, except for Óbidos. However, toxin profiles in bivalves varied between low and elevated toxicities, corresponding to below and above the PST regulatory limit, respectively. The ratio R1=(C1+2):B1, which were the main toxins produced by G. catenatum cells, decreased considerably between elevated and low toxicity cockles, indicating the elimination of C1+2 or conversion of compounds into B1. R2=[(dcSTX)+(dcGTX2+3)]:[(C1+2)+(B1)], which represents the ratio of minor to major toxins in G. catenatum cells, increased substantially in wedge clams (D. trunculus) of low toxicity and less markedly in cockles (C. edule) and mussels (Mytilus spp.). These differences are interpreted as the predominance of a biotransformation phase after exposure to the algal bloom. The toxin profile of surf clams (S. solida) was dominated by decarbamoyl compounds, reflecting intense biotransformation during exposure to blooms. The higher ratio R2 in low toxicity samples suggests that elimination of the produced decarbamoyl toxins was slower than biotransformation.

The new green catalysts derived from waste razor and surf clam shells for biodiesel production in a continuous reactor

AbstractA green catalyst has been derived from a waste material for transesterification of the