Green-lipped Mussel Perna Viridis Research Articles

Transcriptome analysis reveals sex-specific alterations in gonads of green mussel exposed to organophosphorus insecticide triazophos

Triazophos (TP) is a widespread pollutant in aquatic environments. A sex-specific metabolic response in green-lipped mussel Perna viridis to TP exposure was observed in our previous study, and this led us to investigate the mechanisms associated with its toxicity. P. viridis were subjected to chronic exposure (15 days) to TP at 35 μg/L to compare the sex-biased transcriptomic profiles in the gonads of male and female mussels. We identified 632 differentially expressed genes (DEGs) (348 up-regulated and 284 down-regulated) in TP-exposed males, and only 61 DEGs (9 up-regulated and 52 down-regulated) in TP-exposed females. Many DEGs were found to be involved in the nervous, reproductive endocrine, oxidative stress, and immune systems of P. viridis. Additionally, enzymatic activity analysis indicated TP induced neurotoxic effects and oxidative damage to the mussels. Our results demonstrate that the stress response and molecular mechanisms of TP toxicology are different between female and male mussels.

Filtration rates of the green-lipped mussel Perna viridis (Linnaeus, 1758) exposed to high concentration of suspended particles

Filtration rates of the green-lipped mussel Perna viridis (Linnaeus, 1758) exposed to high concentration of suspended particles

Heavy metals in the green-lipped mussel Perna viridis: Are they safe as animal feeds?

The objective of this study was to compare the cited data of Cd and Pb levels in the green-lipped mussels (Perna viridis) with established maximum limits of both metals by European Union (EU) legislation for animal feeds. It was found that most mussel populations from Malaysia (90% for Cd; 87.5% for Pb) and Hong Kong (96.2% for Cd; 100% for Pb) were found to have lower levels of Cd and Pb than the maximum limits for animal feeds by EU. Therefore, both toxic metals based on the feeds of mussel meats on the animals should not pose serious toxicological effects. However, the meat of P. viridis are potential animal feeds similarly to the fish meal. Considering the accumulation of metals in the long term, future biomonitoring of Cd and Pb should focus on animal feed materials on mussel-based origins. Keywords: Animal Feed; Mussels; Safety

Determination of microplastics in the edible green-lipped mussel Perna viridis using an automated mapping technique of Raman microspectroscopy

Microplastics are prevalent in marine environments and seafood and thus can easily end up in human diets. This has raised serious concerns worldwide, particularly in Hong Kong where the seafood consumption per capita can be three times higher than the global average. This study focused on the green-lipped mussel Perna viridis, a popular seafood species which is subject to a high risk of contamination by microplastics due to its filter-feeding nature. P. viridis was collected from five mariculture sites in Hong Kong and assessed for its body load of microplastics using an automated Raman mapping approach. Microplastics were found in all sites, with an average of 1.60–14.7 particles per mussel per site, or 0.21–1.83 particles per g wet weight. Polypropylene, polyethylene, polystyrene and polyethylene terephthalate were detected among the microplastics, mainly as fragments or fibres in the size range of 40–1000 µm. It was estimated that through consumption of P. viridis, the population in Hong Kong could ingest up to 10,380 pieces of microplastics per person per year. These estimated rates were high compared to the values reported worldwide, suggesting the potential human health risk of microplastics in Hong Kong and adjacent areas.

Improved Raman spectroscopy-based approach to assess microplastics in seafood

Microplastics represent an emerging environmental issue and have been found almost everywhere including seafood, raising a great concern about the ecological and human health risks they pose. This study addressed the common technical challenges in the assessment of microplastics in seafood by developing an improved protocol based on Raman spectroscopy and using the green-lipped mussel Perna viridis and the Japanese jack mackerel Trachurus japonicus as the test models. Our findings identified a type of stainless-steel filter membranes with minimal Raman interference, and a combination of chemicals that achieved 99–100% digestion efficiency for both organic and inorganic biomass. This combined chemical treatment reached 90–100% recovery rates for seven types of microplastics, on which the surface modification was considered negligible and did not affect the accuracy of polymer identification based on Raman spectra, which showed 94–99% similarity to corresponding untreated microplastics. The developed extraction method for microplastics was further combined with an automated Raman mapping approach, from which our results confirmed the presence of microplastics in P. viridis and T. japonicus collected from Hong Kong waters. Identified microplastics included polypropylene, polyethylene, polystyrene and poly(ethylene terephthalate), mainly in the form of fragments and fibres. Our protocol is applicable to other biological samples, and provides an improved alternative to streamline the workflow of microplastic analysis for routine monitoring purposes.

Sub-lethal effects of cadmium and copper on RNA/DNA ratio and energy reserves in the green-lipped mussel Perna viridis

This study aims to test if RNA/DNA ratio and various energy reserve parameters (i.e., glycogen, lipid, protein content and total energy reserves) are sensitive biomarkers for indicating stresses induced by metal contaminants in the green-lipped mussel Perna viridis, a common organism for biomonitoring in Southeast Asia. This study was, therefore, designed to examine the effects of cadmium (Cd) and copper (Cu) on these potential biomarkers in two major energy storage tissues, adductor muscle (AM) and hepatopancreas (HP), of P. viridis after sub-lethal exposure to either metal for 10 days. The results showed that neither Cd nor Cu treatments affected the RNA/DNA ratio, glycogen and protein contents in AM and HP. As the most sensitive biomarker in P. viridis, the total lipid content in both AM and HP was significantly decreased in the treatment of 5μg Cu/L and 0.01–0.1μgCd/L, respectively. However, soft-tissue body burdens of Cu or Cd did not significantly correlate with each of the four biomarkers regardless of the tissue type. In addition, AM generally stored more glycogen than HP, whereas HP stored more lipids than AM. We proposed that multiple biomarkers may be employed as an integrated diagnostic tool for monitoring the health condition of the mussels.

Seasonal Variations of Heavy Metals Content in Muscle and Viscera of Green-Lipped Mussel Perna viridis From Da-Peng Bay Lagoon in Taiwan

As a natural lagoon, rich in biological resources including fish, crabs, and bivalves, Da-Peng Bay Lagoon receives the discharges from the neighboring rivers, Kao-ping, Dong-gang, and Lin-Bian, which have harmed the ecology and reduced the water quality of the lagoon. This study analyzes seasonal variation of heavy metals concentration (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the muscle and viscera of the green-lipped mussel Perna viridis from Da-Peng Bay Lagoon. Data from this study may provide information on the use of Perna viridis as a bioindicator for heavy metals pollution in the lagoon. The heavy metals concentrations were greater in viscera than in muscles of the green-lipped mussel Perna viridis. Results showed that the mussel is capable of accumulating high contents of Cu and Zn. Generally, the order of concentrations in the muscle by season was Zn > Cu > Cr or As. In viscera, the general order of concentrations was Zn > Cu > Pb or Cr or As. Mercury was not detected in winter and spring in muscle and viscera. Cadmium displayed significant variation with season. There was also significant correlation between tissue concentration and heavy metals, including Cu, Pb, Zn, Ni, Cd, and As.

Isoform-specific responses of metallothioneins in a marine pollution biomonitor, the green-lipped mussel Perna viridis, towards different stress stimulations.

Metallothioneins (MTs) are commonly used as biomarker for metal pollution assessment in marine ecosystems. Using integrated genomic and proteomic analyses, this study characterized two types of MT isoform in the digestive gland of a common biomonitor, the green-lipped mussel Perna viridis, towards the challenges of a metal (cadmium; Cd) and a non-metal oxidant (hydrogen peroxide; H2 O2 ) respectively. The two isoforms differed in their deduced protein sequences, with 73 amino acids for MT10-I and 72 for MT10-II (a novel type), but both consisted of a high percentage (27.4 to 29.2%) of cysteine. Two-dimensional gel and Western blot showed that the MT proteins were present in multiple isoform spots, and they were further validated to be MT10-I and MT10-II using MS analysis coupled with unrestricted modifications searching. Expression of mRNA revealed that MT10-I responded promptly to Cd but had a lagged induction to H2 O2 treatments, while MT10-II was exclusively induced by Cd treatment over the course of exposure. Expression of the MT proteins also showed a delayed response to H2 O2 , compared to Cd treatments. This study uncovered the potential different functional roles of various MTs isoforms in P. viridis and thus advances the resolution of using MTs as biomarkers in future applications.

Contamination of Heavy Metals and other Organic Pollutants in Perna viridis from the Coastal Waters of Malaysia: A Review Based on 1998 Data

Since 1990s until today, the Asia-Pacific Mussel Watch approach has been widely used for biomonitoring purpose in Malaysia by using the green-lipped mussel Perna viridis in particular. This paper reviewed the concentrations of heavy metals (Cd, Cu, Pb and Zn), Linear Alkylbenzenes (LABs), Polycyclic Aromatic Hydrocarbons (PAHs), phenolic Endocrine Disrupting Chemicals (EDCs) [nonylphenol (NP), octylphenol (OP), and bisphenol A (BPA)] and organochlorine (OC) compounds (PCBs, DDTs, CHLs, HCHs and HCB) in nine mussel populations collected in 1998 (because I involved in the sampling field trip when I was a trainee researcher) from the coastal waters of Malaysia. In fact, all of these data were published separately in five different peer-reviewed journals in the literature (see Yap et al. [6,7]; Tsutsumi et al. [14]; Isobe et al. [15]; Monirith et al. [16]). Since they discussed only based on the group of contaminants which they focused upon, this review paper aimed to see a holistic picture and understanding of the impacts of the different chemical contaminants in relation to the description of the sampling sites. Based on seven mussel populations with complete 11 chemicals (ranging from heavy metals, LABs, PAHs, phenolic EDCs and OCs), a dendrogram was established using single linkage cluster analysis. A dendrogram was established using single linkage cluster analysis showing two major subclusters. The first subcluster comprised Tanjung Rhu, Trayong, Kuala Penyu and Pasir Panjang populations, indicating relatively uncontaminated conditions while the other subcluster consists of Penang, Kg. Pasir Puteh and Anjung Batu which indicated contaminated conditions as it is well supported by the elevated levels of some chemicals. The subcluster combining Penang and Kg. Pasir Puteh populations were mainly due to the elevated levels of LABs and PAHs in both sites while Kg. Pasir Puteh also had elevated levels of Cu, Pb, PCBs and CHLs. Anjung Batu, which is also clustering together with Penang and Kg. Pasir Puteh population can be explained by its elevated levels of three OC compounds namely DDTs, CHLs and HCHs.

De novo transcriptome analysis of Perna viridis highlights tissue-specific patterns for environmental studies.

BackgroundThe tropical green-lipped mussel Perna viridis is a common biomonitor throughout the Indo-Pacific region that is used for environmental monitoring and ecotoxicological investigations. However, there is limited molecular data available regarding this species. We sought to establish a global transcriptome database from the tissues of adductor muscle, gills and the hepatopancreas of P. viridis in an effort to advance our understanding of the molecular aspects involved during specific toxicity responses in this sentinel species.ResultsIllumina sequencing results yielded 544,272,542 high-quality filtered reads. After de novo assembly using Trinity, 233,257 contigs were generated with an average length of 1,264 bp and an N50 length of 2,868 bp; 192,879 assembled transcripts and 150,111 assembled unigenes were obtained after clustering. A total of 93,668 assembled transcripts (66,692 assembled genes) with putative functions for protein domains were predicted based on InterProScan analysis. Based on similarity searches, 44,713 assembled transcripts and 25,319 assembled unigenes were annotated with at least one BLAST hit. A total of 21,262 assembled transcripts (11,947 assembled genes) were annotated with at least one well-defined Gene Ontology (GO) and 5,131 assembled transcripts (3,181 assembled unigenes) were assigned to 329 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The quantity of assembled unigenes and transcripts obtained from male and female mussels were similar but varied among the three studied tissues, with the highest numbers recorded in the gills, followed by the hepatopancreas, and then the adductor muscle. Multivariate analyses revealed strong tissue-specific patterns among the three different tissues, but not between sexes in terms of expression profiles for annotated genes in various GO terms, and genes associated with stress responses and degradation of xenobiotics. The expression profiles of certain selected genes in each tissue type were further validated using real-time quantitative polymerase chain reaction assays and a similar tissue-specific trend was seen.ConclusionsThe extensive sequence data generated from this study will provide a valuable molecular resource for facilitating environmental studies with P. viridis, and highlight the importance of tissue-specific approaches in the future.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-804) contains supplementary material, which is available to authorized users.

Setting water quality objectives for the health of freshwater fish

An important responsibility of the Environment Protection Authority, Victoria, is to set objectives for levels of environmental contaminants. To support the development of environmental objectives for water quality, a need has been identified to understand the dual impacts of concentration and duration of a contaminant on biota in freshwater streams. For suspended solids contamination, information reported by Newcombe and Jensen [North American Journal of Fisheries Management, 16(4):693--727, 1996] study of freshwater fish and the daily suspended solids data from the United States Geological Survey stream monitoring network is utilised. The study group was requested to examine both the utility of the Newcombe and Jensen and the USA data, as well as the formulation of a procedure for use by the Environment Protection Authority Victoria that takes concentration and duration of harmful episodes into account when assessing water quality. The extent to which the impact of a toxic event on fish health could be modelled deterministically was also considered. It was found that concentration and exposure duration were the main compounding factors on the severity of effects of suspended solids on freshwater fish. A protocol for assessing the cumulative effect on fish health and a simple deterministic model, based on the biology of gill harm and recovery, was proposed. References D. W. T. Au, C. A. Pollino, R. S. S Wu, P. K. S. Shin, S. T. F. Lau, and J. Y. M. Tang. Chronic effects of suspended solids on gill structure, osmoregulation, growth, and triiodothyronine in juvenile green grouper epinephelus coioides. Marine Ecology Press Series, 266:255--264, 2004. J.C. Bezdek, S.K. Chuah, and D. Leep. Generalized k-nearest neighbor rules. Fuzzy Sets and Systems, 18:237--26, 1986. E. T. Champagne, K. L. Bett-Garber, A. M. McClung, and C. Bergman. {Sensory characteristics of diverse rice cultivars as influenced by genetic and environmental factors}. Cereal Chem., {81}:{237--243}, {2004}. S. G. Cheung and P. K. S. Shin. Size effects of suspended particles on gill damage in green-lipped mussel perna viridis. Marine Pollution Bulletin, 51(8--12):801--810, 2005. D. H. Evans. The fish gill: site of action and model for toxic effects of environmental pollutants. Environmental Health Perspectives, 71:44--58, 1987. G. C. Grigg. The failure of oxygen transport in a fish at low levels of ambient oxygen. Comp. Biochem. Physiol., 29:1253--1257, 1969. G. Holmes, A. Donkin, and I.H. Witten. {Weka: A machine learning workbench}. In Proceedings of the Second Australia and New Zealand Conference on Intelligent Information Systems, volume {24}, pages {357--361}, {Brisbane, Australia}, {1994}. {IEEE Computer Society}. D. D. Macdonald and C. P. Newcombe. Utility of the stress index for predicting suspended sediment effects: response to comments. North American Journal of Fisheries Management, 13:873--876, 1993. C. P. Newcombe. Suspended sediment in aquatic ecosystems: ill effects as a function of concentration and duration of exposure. Technical report, British Columbia Ministry of Environment, Lands and Parks, Habitat Protection branch, Victoria, 1994. C. P. Newcombe and J. O. T. Jensen. Channel suspended sediment and fisheries: A synthesis for quantitative assessment of risk and impact. North American Journal of Fisheries Management, 16(4):693--727, 1996. C. P. Newcombe and D. D. Macdonald. Effects of suspended sediments on aquatic ecosystems. North American Journal of Fisheries Management, 11(1):72--82, 1991. K. Schmidt-Nielsen. Scaling. Why is animal size so important? Cambridge University Press, NY, 1984. J. S. Schwartz, A. Simon, and L. Klimetz. Use of fish functional traits to associate in-stream suspended sediment transport metrics with biological impairment. Environmental Monitoring and Assessment, 179(1--4):347--369, 2011. E. Al Shaw and J. S. Richardson. Direct and indirect effects of sediment pulse duration on stream invertebrate assemblages and rainbow trout (Oncorhynchus mykiss) growth and survival. Canadian Journal of Fish and Aquatic Science, 58:2213--2221, 2001. P. Tiwari and H. Hasegawa. {Demand for housing in Tokyo: A discrete choice analysis}. Regional Studies, {38}:{27--42}, {2004}. Y. Tramblay, A. Saint-Hilaire, T. B. M. J. Ouarda, F. Moatar, and B Hecht. Estimation of local extreme suspended sediment concentrations in california rivers. Science of the Total Environment, 408:4221--

Antipredatory responses of Perna viridis (Linnaeus, 1758) under acute hypoxia and low salinity

The antipredatory responses/attachment behaviour of the green-lipped mussel Perna viridis were studied under combined stresses of hypoxia and low salinity in the presence/absence of its predator, the swimming crab Thalamita danae. There were two oxygen concentrations (1.5 mg l–1 O2 = hypoxic and 6.0 mg l–1 O2 = normoxic) and two salinity levels (15‰ = low, 30‰ = normal). Byssus production performances (including byssal-thread number, byssal-thread diameter, byssal-thread length, cumulative byssal-thread length and volume and frequency of stalk-shedding) were evaluated after 48 h. All variables were significantly affected by dissolved oxygen (DO), salinity and predator presence. Interactive effects of these three factors on byssus production were also observed. Byssus production and frequency of stalk-shedding were lowest in hypoxia × low salinity, followed by normoxia × low salinity, hypoxia × normal salinity, while normoxia × normal salinity exhibited the highest values in both predator-presence and non-predator-presence groups. At each treatment of DO and salinity, all parameters in predator-presence groups were significantly higher than in non-predator-presence groups. Our results indicate that the environmental hypoxia and low salinity impair anti-predatory/attachment behaviour and show some synergistic effects. Since reduced byssus production makes the mussels more vulnerable to crab predators, the co-occurrence of hypoxia and low salinity may increase the rates of crab predation on P. viridis in the field.

Trace Metal Concentrations in The Green-Lipped Mussel Perna viridis (Linnaeus, 1758) Collected From Maheshkhali Channel, Cox’s Bazar, Bangladesh

The green-lipped mussel Perna viridis (L.) were collected from four sampling locations of the Maheshkhali channel, Cox’s Bazar, Bangladesh to determine the concentration level of zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb). The concentrations (μg/g dry weight) of these trace metals ranged from 28.12 to 33.82 for Zn, 7.26 to 8.81 for Cu, 0.04 to 0.08 for Cd and 0.19 to 0.75 for Pb. The concentrations of trace metals in the mussel tissue were found at lower level than the permissible limits for human consumption. In addition, these metal concentrati-ons are also considered to be low when compared with regional data using P. viridis as a bio-monitoring agent.

Short Communication Characterization of eight novel microsatellite markers in the green-lipped mussel Perna viridis (Mytilidae)

The green lipped mussel, also known as the Asian green mussel (Perna viridis) is a fast reproducing and valuable food source, but it is also considered an invasive species and can clog and damage pipes and marine equipment. Eight novel polymorphic microsatellite loci for P. viridis were isolated and characterized. Microsatellite polymorphism was evaluated in 30 individuals collected from Xiamen, China. The number of alleles per locus and the polymorphism information content ranged from 2 to 5 and from 0.3092 to 0.7031, respectively. The observed and expected heterozygosities were 0.1538-0.8400 and 0.1448-0.6833, respectively. The loci identified in this study could provide a useful tool for the genetic population structure analysis of P. viridis.

Immune parameter changes of hemocytes in green-lipped mussel Perna viridis exposure to hypoxia and hyposalinity

Marine hypoxia owing to nutrient enrichment of water bodies by anthropogenic activities has become a global problem for several decades. Another marine environmental factor, salinity, plays an important role for marine organisms and fluctuates greatly in estuarine and coastal ecosystem, where hypoxia frequently occurs. The present study evaluated the interactive effects of hypoxia and salinity on immune functions of hemocytes in the green-lipped mussel Perna viridis, which widely distributes in estuarine and coastal waters of the Indo-Pacific region. Mussels were subjected to six combinations of oxygen levels (hypoxia: 1.5mg O2 l−1, normoxia: 6.0mg O2 l−1) and salinities (15‰, 22‰ and 30‰) for 168h. Mussel hemocytes were sampled after 24h, 48h, 96h and 168h exposure, for analysis of immune functions including hemocyte mortality, phagocytosis, esterase, reactive oxygen species (ROS) production, lysosomal content and total hemocyte counts using flow cytometric methods. Thereafter, all treatments were recovered to normoxic condition (6.0mg O2 l−1) and salinity 30‰ for 24h to study the recovery of immune functions from the combined hypoxic and hyposaline stresses. Interactive effects of dissolved oxygen (DO) and salinity on all immune parameters were observed during the experiment. Generally, hemocyte mortality was higher at low salinity than that at high salinity levels; higher hemocyte mortality was also noted when mussels were exposed to hypoxia compared with normoxia. Phagocytosis at low salinities and hypoxia was decreased compared to normal DO and salinity treatment, respectively. The activity of esterase and ROS production at low salinity and hypoxia were reduced, respectively. Lysosomal content and total hemocyte counts were lower at low salinity and hypoxia compared to other treatments, respectively. After 24h recovery, hypoxia and salinity effects were still significant among previous treatments, indicating immune functions of P. viridis could not recover from combined stresses in a short time.

Effects of ocean acidification on the metabolic rates of three species of bivalve from southern coast of China

Oceanic uptake of anthropogenic carbon dioxide results in a decrease in seawater pH, a process known as "ocean acidification". The pearl oyster Pinctada fucata, the noble scallop Chlamys nobilis, and the green-lipped mussel Perna viridis are species of economic and ecological importance along the southern coast of China. We evaluated the effects of seawater acidification on clearance, respiration, and excretion rates in these three species. The ammals were reared in seawater at pH 8.1 (control), 7.7, or 7.4. The clearance rate was highest at pH 7.7 for P. fucata and at pH 8.1 for C. nobilis and P. viridis. The pH had little effect on the respiration rate of P. fucata and P. viridis. In contrast, the respiration rate was significantly lower at pH 7.4 in C. nobilis. The excretion rate was significantly lower at pH 7.4 than pH 8.1 for all species. The results indicate that the reduction in seawater pH likely affected the metabolic process (food intake, oxygen consumption, and ammonia excretion) of these bivalves. Different species respond differently to seawater acidification. Further studies are needed to demonstrate the exact mechamsms for this effect and evaluate adaptability of these bivalves to future acidified oceans.

Chronic hypoxia and low salinity impair anti-predatory responses of the green-lipped mussel Perna viridis

The effects of chronic hypoxia and low salinity on anti-predatory responses of the green-lipped mussel Perna viridis were investigated. Dissolved oxygen concentrations ranged from hypoxic to normoxic (1.5 ± 0.3 mg l−1, 3.0 ± 0.3 mg l−1 and 6.0 ± 0.3 mg l−1), and salinities were selected within the variation during the wet season in Hong Kong coastal waters (15‰, 20‰, 25‰ and 30‰). The dissolved oxygen and salinity significantly affected some anti-predatory responses of mussel, including byssus production, shell thickness and shell weight, and the adductor diameter was only significantly affected by salinity. Besides, interactive effects of dissolved oxygen and salinity on the byssus production and shell thickness were also observed. In hypoxic and low salinity conditions, P. viridis produced fewer byssal threads, thinner shell and adductor muscle, indicating that hypoxia and low salinity are severe environmental stressors for self-defence of mussel, and their interactive effects further increase the predation risk.

Combined Effects of Dissolved Oxygen and Salinity on Growth and Body Composition of Juvenile Green-Lipped MusselPerna viridis

The green-lipped mussel Perna viridis is distributed widely in estuarine and coastal areas of the Indo-Pacific region and is regarded as a cultured mussel or by-product in aquaculture. However, in estuarine and coastal waters where salinity varies with freshwater input and rainfall during the wet season, hypoxia frequently occurs, especially when waters are highly eutrophic. The current study aimed to evaluate the effects of two key environmental factors in estuarine and coastal waters—dissolved oxygen (DO) and salinity—on growth and body composition of juvenile green-lipped mussels P. viridis. Parameters studied included shell length (SL), tissue dry weight (TDW), condition index (CI), specific growth rate (shell length, SGR L ; tissue dry weight, SGR W ), moisture content (MC), crude protein (CP), crude fat (CF), crude carbohydrate (CC), crude ash (CA), and energy content (EC). Mussels were cultured for 6 wk at 4 salinities (15, 20, 25, and 30) and 3 dissolved oxygen concentrations (1.5 ± 0.3, 3.0 ± 0.3, and 6.0 ± 0.3 mg 02/L) in a 4 × 3 factorial design. All growth parameters (SL, TDW, CI, SGR L , and SGR W ) decreased under reduced DO and salinities, but interactive effects between these 2 factors were statistically indistinguishable except for SGR W . Higher percentages of CF and CP, and lower percentages of CC were obtained at reduced salinities and DO. When changes in biochemical content (weight per individual) were compared, both CP and CC content decreased significantly as salinity or DO decreased, whereas no pattern was observed for CF. EC (calories per gram) was not significantly different among DO treatments, but varied significantly with salinity. Total energy content (calories per individual), however, increased significantly with both DO and salinity, but the interaction between salinity and DO was statistically indistinguishable.

Characterization of subpopulations and immune-related parameters of hemocytes in the green-lipped mussel Perna viridis

The green-lipped mussel Perna viridis is distributed widely in the estuarine and coastal areas of the Indo-Pacific region and extensively cultured as an inexpensive protein source. Morphology and immunological activities of hemocytes of P. viridis were investigated using flow cytometry and light and electron microscopy. Three major types of hemocytes were identified in the hemolymph, including dense-granulocyte, semi-granulocyte (small and large size) and hyalinocyte. Other hemocytes, which occurred in low numbers, included granulocytes with different electron-dense/lucent granules and hemoblast-like cells. Based on flow cytometry, two subpopulations were identified. Granulocytes were larger cells, and the more abundant, containing numerous granules in the cytoplasm, and hyalinocytes were the smaller and less abundant with the fewest granules. Flow cytometry revealed that the granulocytes were more active in cell phagocytosis, contained the higher lysosomal content, and showed higher esterase activity and reactive oxygen species (ROS) generation compared with hyalinocytes. Immune functions assessed by the flow cytometry indicated that the granulocytes were the main hemocytes involved in the cellular defence in P. viridis.

Differential proteomic responses in hepatopancreas and adductor muscles of the green-lipped mussel Perna viridis to stresses induced by cadmium and hydrogen peroxide

This study aimed to reveal the proteomic responses in the hepatopancreas and adductor muscle of a common biomonitor, Perna viridis after 14-day exposure to two model chemicals, cadmium (Cd; a toxic metal) and hydrogen peroxide (H 2O 2; a pro-oxidant), using two-dimensional gel electrophoresis coupled with multivariate statistical analyses. Unique sets of tissue-specific protein expression signatures were revealed corresponding to the two treatment groups. In the hepatopancreas, 15 and 2 spots responded to Cd and H 2O 2 treatments respectively. 6 and 7 spots were differentially expressed in the adductor muscle for Cd and H 2O 2 treatments, respectively. 15 differentially expressed spots were successfully identified by MALDI-TOF/TOF MS analysis. These proteins are involved in glycolysis, amino acid metabolism, energy homeostasis, oxidative stress response, redox homeostasis and protein folding, heat-shock response, and muscle contraction modulation. This is the first time, to have demonstrated that Cd exposure not only leads to substantial oxidative stress but also results in endoplasmic reticulum stress in hepatopancreas of the mussel. Such notable stress responses may be attributable to high Cd accumulation in this tissue. Our results suggested that investigations on these stress-associated protein changes could be used as a new and complementary approach in pollution monitoring by this popular biomonitor species.