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Concept: Mussel


Zebra mussels (Dreissena polymorpha) are known to increase water clarity and affect ecosystem processes in invaded lakes. During the last decade, the conspecific quagga mussels (D. rostriformis bugensis) have displaced zebra mussels in many ecosystems including shallow lakes such as Oneida Lake, New York. In this study, an eight-week mesocosm experiment was conducted to test the hypothesis that the displacement of zebra mussels by quagga mussels leads to further decreases in phytoplankton and increases in water clarity resulting in increases in benthic algae. We found that the presence of zebra mussels alone (ZM), quagga mussels alone (QM), or an equal number of both species (ZQ) reduced total phosphorus (TP) and phytoplankton Chl a. Total suspended solids (TSS) was reduced in ZM and ZQ treatments. Light intensity at the sediment surface was higher in all three mussel treatments than in the no-mussel controls but there was no difference among the mussel treatments. There was no increase in benthic algae biomass in the mussel treatments compared with the no-mussel controls. Importantly, there was no significant difference in nutrient (TP, soluble reactive phosphorus and NO3-) levels, TSS, phytoplankton Chl a, benthic algal Chl a, or light intensity on the sediment surface between ZM, QM and ZQ treatments. These results confirm the strong effect of both mussel species on water clarity and indicate that the displacement of zebra mussel by an equivalent biomass of quagga mussel is not likely to lead to further increases in water clarity, at least for the limnological conditions, including summer temperature, tested in this experiment.

Concepts: Invasive species, Mussel, Great Lakes, Zebra mussel, Quagga mussel, Dreissenidae, Dreissena, Lake Erie


Biofouled debris from the 2011 Great East Japan earthquake and tsunami has landed in the Northeast Pacific and along the Hawaiian Islands since 2012. As of 2017, >630 biofouled debris items with >320 living species of algae, invertebrates, and fish have been examined. The invasive mussel Mytilus galloprovincialis was present on >50% of those items. Size, reproduction, and growth of this filter-feeding species were examined to better understand long-distance rafting of a coastal species. The majority of mussels (79%) had developing or mature gametes, and growth rates averaged 0.075±0.018 SE mm/day. Structural and elemental (barium/calcium) analysis of mussel shells generated estimates of growth in coastal waters (mean=1.3 to 25mm total length), which provides an indication of residence times in waters along North America and the Hawaiian Islands prior to landing. Detailed studies of individual species contribute to our understanding of debris as a transport vector and aid efforts to evaluate potential risks associated with marine debris.

Concepts: Hawaii, United States, Japan, Pacific Ocean, Mussel, Mytilidae, Island, Zebra mussel


BACKGROUND: The conceptual validity of kinetic gait analysis and disability outcome assessment methods has guided their use in the assessment of pain caused by osteoarthritis (OA). No consensus on the best clinical methods for pain evaluation in canine OA exists, particularly, when evaluating treatments where a smaller treatment effect is anticipated than with pharmacological pain killers. This study thus aimed at determining the technical validity of some clinical endpoints on OA pain in dogs using the green-lipped mussel (GLM)-enriched diet. Twenty-three adult dogs with clinical OA completed the prospective controlled study. All the dogs were fed a balanced diet over a 30-day control period followed by a GLM-enriched diet over a 60-day period. The kinetic gait analysis parameter (PVFBW, peak vertical force adjusted for body weight change), electrodermal activity (EDA), and a standardized multifactorial pain questionnaire (MFQ) were performed on day (D) 0 (inclusion), D30 (start) and D90 (end). The owners completed a client-specific outcome measures (CSOM) instrument twice a week. Motor activity (MA) was continuously recorded in seven dogs using telemetered accelerometric counts. We hypothesized that these methods would produce convergent results related to diet changes. A Type I error of 0.05 was adjusted to correct for the multiplicity of the primary clinical endpoints. RESULTS: Neither the EDA nor the MFQ were found reliable or could be validated. Changes in the PVFBW (Padj = 0.0004), the CSOM (Padj = 0.006) and the MA intensity (Padj = 0.02) from D0 to D90 suggested an effect of diet(s). Only the PVFBW clearly increased after the GLM-diet (Padj = 0.003). The CSOM exhibited a negative relationship with the PVFBW (P = 0.02) and MA duration (P = 0.02). CONCLUSIONS: The PVFBW exhibited the best technical validity for the characterization of the beneficial effect of a GLM-enriched diet. The CSOM and MA appeared less responsive following a GLM-diet, but these measures appeared complementary to gait analysis. Apparently, the CSOM provides the capacity to rely on pain OA assessment influenced by both lameness quantification (PVFBW) and physical functioning (MA).

Concepts: Evaluation, Obesity, Assessment, Logic, Gait, Mussel, New Zealand green-lipped mussel, House of Councillors


The purpose of the present study was to evaluate the effects of PCSO-524®, a marine oil lipid and n-3 LC PUFA blend, derived from New Zealand green- lipped mussel (Perna canaliculus), on markers of muscle damage and inflammation following muscle damaging exercise in untrained men.

Concepts: Present, Omega-3 fatty acid, New Zealand, Eicosapentaenoic acid, Docosahexaenoic acid, Prostaglandin, Mussel, New Zealand green-lipped mussel


Uptake of seven contaminants regularly detected in surface waters and spanning a range of hydrophobicities (log Dow -1 to 5) was studied for two species of freshwater bivalves, the native mussel Anodonta californiensis and the invasive clam Corbicula fluminea. Batch systems were utilized to determine compound partitioning and flow-through systems, comparable to environmental conditions in effluent dominated surface waters, were used to determine uptake and depuration kinetics. Uptake of compounds was independent of bivalve type. Log BCF values were correlated with log Dow for non-ionized compounds with the highest BCF value obtained for triclocarban (TCC). TCC concentrations were reduced in the water column due to bivalve activity. Anionic compounds with low Dow values, i.e., clofibric acid and ibuprofen, were not removed from water, while the organic cation propranolol showed biouptake similar to TCC. Batch experiments supported compound uptake patterns observed in flow-through experiments. Contaminant removal from water was observed through accumulation in tissue or settling as excreted pseudofeces or feces. The outcomes of this study indicate the potential utility of bivalve augmentation to improve water quality by removing hydrophobic trace organic compounds found in natural systems.

Concepts: Water, Bivalves, Mollusca, Environmental science, Bivalvia, Mussel, Clam, Corbicula fluminea


Greenshell™ mussels (Perna canaliculus) were dry-stored at 6.44±0.54°C for 8 days during which time volatile organic compounds (VOCs) were monitored using SPME GC-MS. Thirty-four VOCs were identified in homogenised mussel meat and 29 in the mussel liquor (i.e. the seawater enclosed in the mantle cavity). Of the 34 VOCs identified 20 were reliably identified throughout the storage treatment and 9 were found to change in relative concentration in homogenised mussel meat. Dimethyl sulphide, 1-penten-3-ol, 1-hexen-3-ol and 1-octen-3-ol increased during storage, whereas pentanal, hexanal, heptanal, octanal and 3-undecen-2-one decreased. In the mussel liquor, dimethyl sulphide was undetectable pre-storage, becoming detectable after 2 days, and a large increase was noted after 6 days. SPME GC-MS was a useful tool for monitoring VOC profiles of Greenshell™ mussels and could aid in the development of technologies that monitor and improve product quality and consistency.

Concepts: Mass spectrometry, Laboratory techniques, Solid phase microextraction, Volatile organic compound, Organic compounds, Mussel, Volatile, New Zealand green-lipped mussel


Trace metal concentrations in the muscle of the bivalve Villorita cyprinoides from the Cochin backwaters (southwest coast of India) were investigated during the monsoon, post-monsoon and pre-monsoon periods. The seasonal average ranges of metals (μg g(-1), dry weight) in the bivalve were as follows: Fe (18,532.44-28,267.05), Co (23.25-37.58), Ni (10.56-19.28), Cu (3.58-11.35), Zn (48.45-139.15), Cd (1.06-1.50) and Pb (3.05-4.35). The marginally elevated metal concentrations in bivalve muscles are probably related to high influx of metals as a result of pollution from the industries and agricultural fields with consequent increased bioavailability of metals to the bivalve. Evaluation of the risks to human health associated with consumption of the bivalves suggested that there is no health risk for moderate shellfish consumers. A regular and continuous biomonitoring program is recommended to establish V. cyprinoides as a bioindicator for assessing the effects of trace metal pollution and to identify future changes to conserve the “health” of this fragile ecosystem.

Concepts: Iron, Metal, Copper, Mollusca, Bivalvia, Mussel, Clam, Scallop


The periodic occurrence of Paralytic Shellfish Poisoning (PSP) toxins in UK surf clams and the recent move away from biological assays for PSP testing resulted in the need to determine method performance characteristics for the replacement analytical method in this species. With the requirement for laboratory reference materials to aid this validation together with known issues relating to toxin transformation in live clams and homogenised tissue, there was the need to assess the toxin transformation characteristics of PSP toxins in surf clam tissue. Initial work examined the rates of toxin transformation in UK surf clam tissue incubated with toxin standards, showing rapid transformation of N-sulfocarbamoyl toxins with slower transformation of carbamate toxins. Full transformational pathways were determined using a combination of three different analytical methods and confirmed the major expected transformations involving decarbamoylation, with some evidence for additional reaction pathways. Results obtained from the analysis of surf clam and oyster tissues incubated with varying concentrations of toxic Alexandrium algae highlighted expected transformation reactions, although significant differences were observed in the extent of the transformations amongst the range of toxins studied, with less efficient transformation of N-hydroxylated toxins as compared with other carbamate and N-sulfocarbamoyl toxins. Analysis of PSP-toxic incurred oyster, scallop and mussel tissues incubated with variable proportions of surf clam tissue showed large differences in the extent of the transformations. Total conversion of N-sulfocarbamoyl toxins was confirmed at low relative proportions of surf clam tissue in all three species, whereas transformation of carbamate toxins was found to occur only in the presence of higher proportions of surf clam tissue in oysters and mussels in comparison with scallops. Results enabled the production of three laboratory reference materials prepared following incubation of incurred homogenates with optimum proportions of surf clam tissue, resulting in materials containing a large number of PSP toxins. Stability experiments provided good preliminary evidence for the stability of these targeted materials under storage conditions. The work therefore provides both additional information relating to the transformational activity in UK surf clams and highlights a good potential method for the targeted production of reference materials which include a wider range of toxins than normally present in naturally incurred shellfish.

Concepts: Seafood, Bivalvia, Mussel, Shellfish, Clam, Scallop, Paralytic shellfish poisoning, Shellfish poisoning


PCBs are a persistent environmental problem due to their high stability and lipophilicity. The non-ortho- and the mono-ortho-substituted PCBs (dioxin-like-PCBs) share a common and well-described toxicity mechanism in vertebrates, initially involving binding to cytosolic AhRs. Invertebrate AhRs, however, show a lack of dioxin binding, and little information is available regarding the mechanism of toxicity of dl-PCBs in invertebrates. In this study, a proteomic approach was applied to analyse the variations in the pattern of the gill proteome of the freshwater mussel Dreissena polymorpha. Mussels were exposed to a mixture of dl-PCBs, and to perform a more in-depth evaluation, we chose to investigate the role of gender in the proteome response by analysing male and female mussels separately. The results revealed significant modulation of the gill tissue proteome: glycolysis and Ca(2+) homeostasis appear to be the main pathways targeted by dl-PCBs. In light of the differences between the male and female gill proteome profiles following exposure to dl-PCBs, further in-depth investigations of the role of gender in the protein expression profiles of a selected biological model are required.

Concepts: Male, Metabolism, Gender, Mollusca, Mussel, Zebra mussel, Quagga mussel, Dreissenidae


Outbreaks of fatal leukemia-like cancers of marine bivalves throughout the world have led to massive population loss. The cause of the disease is unknown. We recently identified a retrotransposon, Steamer, that is highly expressed and amplified to high copy number in neoplastic cells of soft-shell clams (Mya arenaria). Through analysis of Steamer integration sites, mitochondrial DNA single-nucleotide polymorphisms (SNPs), and polymorphic microsatellite alleles, we show that the genotypes of neoplastic cells do not match those of the host animal. Instead, neoplastic cells from dispersed locations in New York, Maine, and Prince Edward Island (PEI), Canada, all have nearly identical genotypes that differ from those of the host. These results indicate that the cancer is spreading between animals in the marine environment as a clonal transmissible cell derived from a single original clam. Our findings suggest that horizontal transmission of cancer cells is more widespread in nature than previously supposed. PAPERCLIP.

Concepts: DNA, Gene, Genetics, Cancer, Neoplasm, Mussel, Clam, Prince Edward Island