First Evaluation of Microplastic Content in Benthic Filter-feeders of the Gulf of La Spezia (Ligurian Sea)

The ingestion and retention of microplastics of filter-feeder organisms represent a risk for the final consumers and the environment. Biomonitoring is necessary to deal with the effects of plastic material pollution. The selection of the monitored organisms strongly affects the relevance of the results and the understanding of the environmental conditions. The results discussed in this paper highlight the differences in the estimate of microplastic pollution depending on the species subject of study. Ascidia spp. specimens retained a value five-fold higher (0.62 MP/g) than bivalve species (Crassostrea gigas 0.11 MP/g; Mytilus galloprovincialis 0.05 MP/g; Anomia ephippium 0.12 MP/g).     

灿烂弧菌对厚壳贻贝免疫指标和消化酶活性的影响

为探究灿烂弧菌对厚壳贻贝免疫指标和消化酶活性的影响,用1×10~6、1×10~7、1×10~8个/mL 3个浓度的灿烂弧菌刺激厚壳贻贝,探讨弧菌刺激后厚壳贻贝的一氧化氮合酶(NOS)、一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MAD)等免疫指标和淀粉酶、蛋白酶等消化酶的变化情况。结果显示,灿烂弧菌刺激48 h后,厚壳贻贝足、鳃、消化腺等组织中仅消化腺的NOS活性较对照组有显著升高,且酶活性随初始细菌浓度的升高而升高,故选用消化腺来测定灿烂弧菌刺激后72 h内的免疫指标和消化酶活性的变化。灿烂弧菌刺激后,48 h内NOS活性较对照组均显著升高。NO含量较对照组均显著升高,与NOS显现相同变化趋势。SOD活性在各浓度灿烂弧菌刺激下较对照组均显著升高,而MAD含量在实验组中含量显著低于对照组。淀粉酶活性在实验组中显著低于对照组,总体呈现先下降后升高的趋势。蛋白酶活性在各实验组中均呈现先升高后下降的趋势。研究表明,灿烂弧菌对厚壳贻贝免疫指标和蛋白酶活性的升高有诱导作用,但对蛋白酶的活性有抑制作用。本研究初步探明了厚壳贻贝对灿烂弧菌的免疫应答机制,为进一步研究灿烂弧菌和厚壳贻贝相互作用机制以及厚壳贻贝免疫机制奠定了基础。     

Anti-Inflammatory Effects of Mytilus coruscus Polysaccharide on RAW264.7 Cells and DSS-Induced Colitis in Mice

Considerable literature has been published on polysaccharides, which play a critical role in regulating the pathogenesis of inflammation and immunity. In this essay, the anti-inflammatory effect of Mytilus coruscus polysaccharide (MP) on lipopolysaccharide-stimulated RAW264.7 cells and a dextran sulfate sodium (DSS)-induced ulcerative colitis model in mice was investigated. The results showed that MP effectively promoted the proliferation of RAW264.7 cells, ameliorated the excessive production of inflammatory cytokines (TNF-α, IL-6, and IL-10), and inhibited the activation of the NF-κB signaling pathway. For DSS-induced colitis in mice, MP can improve the clinical symptoms of colitis, inhibit the weight loss of mice, reduce the disease activity index, and have a positive effect on the shortening of the colon caused by DSS, meliorating intestinal barrier integrity and lowering inflammatory cytokines in serum. Moreover, MP makes a notable contribution to the richness and diversity of the intestinal microbial community, and also regulates the structural composition of the intestinal flora. Specifically, mice treated with MP showed a repaired Firmicutes/Bacteroidetes ratio and an increased abundance of some probiotics like Anaerotruncus, Lactobacillus, Desulfovibrio, Alistipe, Odoribacter, and Enterorhabdus in colon. These data suggest that the MP could be a promising dietary candidate for enhancing immunity and protecting against ulcerative colitis.     

Decreases in multi-locus heterozygosity in suspension-cultured mussels (Mytilus edulis) through loss of the more heterozygous individuals

The mean multi-locus heterozygosity (MLH) of suspension-cultured mussels has been reported to decrease within a few months after traditional sleeving in previous studies. Two experiments were carried out to determine if this decrease could be attributed to the more rapid migration of the more heterozygous mussels out of the mesh tubes after sleeving. Since these individuals occur in greater numbers at the periphery of the sleeves, they are more susceptible to fall-offs. In the first experiment, the mean MLH of the mussels emerging from the mesh tubes was significantly higher than the MLH of the spat used for sleeving two weeks before. In a second experiment with caged and free sleeves under field conditions, a significant decrease in MLH was observed, but only for the mussels from the free sleeves. This decrease occurred in late December, only one month after sleeving. It is hypothesized that the experimental cages limited turbulence and thus fall-offs during the weeks following sleeving. As a consequence, the slower moving homozygotes were able to catch up with the faster heterozygotes at the sleeve's periphery. In contrast, mussels in the free sleeves may have experienced more turbulent conditions leading to high fall-offs of the more heterozygous mussels at the sleeve's periphery during the crucial period following sleeving. These losses could impact mussel production since MLH explained 32% of the variation in individual dry tissue weight in this study. Furthermore, the total fresh weight of mussels with high MLH (5–7 heterozygous loci) was almost twice that of the mussels with low MLH (0–2 heterozygous loci) about one year after sleeving: 11.38 vs. 5.95 g. In addition, there were 3.7 times more commercial-sized mussels (>50 mm) with a high MLH than with a low MLH (80% vs. 21.5%). In contrast to traditional sleeving with plastic mesh tubes, a new method of mechanical sleeving provides continuous sleeves wrapped in cotton cloth. This biodegradable cloth helps retain the heterozygotes on the sleeves before it disintegrates.     

厚壳贻贝的模型拟合与壳体曲面分析

以长度85~110 mm的野生厚壳贻贝作为研究对象,探究贻贝壳体模型特征。利用光学扫描仪得到相应的样本点云文件,通过geomagic wrap软件处理优化点云数据,得到质量优良的三维样本模型;利用Matlab软件拟合三维样本模型,得到最佳的拟合模型——标准模型,并将标准模型数字化,得到标准模型壳体外曲面(W)和壳体内曲面(N)的数学函数关系式。检验数字化模型、标准模型、样本模型之间的误差,得出三者间的平均误差均不超过0.06 mm。因此,可以使用数字化贻贝模型替代样本模型来指导贻贝定向、固定装置零部件的设计,规划最佳的贝肉剥离路线,为打造现代化贻贝加工流水线提供理论基础。     

Hatchery broodstock conditioning of the blue mussel <Emphasis Type="Italic">Mytilus edulis</Emphasis> (Linnaeus, 1758). Part II. New formulated feeds offer new perspectives to commercial hatcheries

Five diets were compared for their efficiency at maturing the gonads of the blue mussel, Mytilus edulis. The diets consisted of a 1:1:1 mixture of Isochrysis galbana (T-Iso), Pavlova lutheri, and Chaetoceros calcitrans given at concentrations of 2.4 × 10¹¹ cells day^?1 for the positive control treatment (PF) and 3.0 × 10¹⁰ cells day^?1 (=1/8) for the negative control treatment (NF). The other three treatments, MB10+, MyStock+, and Frippak+, consisted of the NF diet supplemented with one of the micro-encapsulated diets MB10 (mixture of dried algae), MyStock (formulated diet), and FRiPPAK^® Fresh #1 CAR (larval shrimp diet) at a level of 0.2% of the live weight (LW). Treatments PF, MB10+, and MyStock+ led to high percentages of spawning animals (80, 78, and 85%, respectively) and large numbers of eggs (on average 3.0 × 10⁶ eggs female^?1). Females given the NF and Frippak+ treatments produced only half the number of eggs per female, and only 17 and 6%, respectively, of the animals spawned. A high hatching rate was observed for all treatments, 71% for the pure algae diets PF and NF and more than 80% for the micro-encapsulated diets. The larvae resulting from the NF treatment were smaller, with 41% of D-larvae measuring less than 90 μm, whereas with the other treatments only 5–11% belonged to that size category. The four most important fatty acids found in mussel eggs were 16:0, 16:1(n?7), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA); these represented at least 50% of the fatty acids in all treatments. The high DHA content of MB10 and MyStock was not reflected in the fatty acid composition of the eggs whereas the high concentration of linoleic acid in MyStock was. To our knowledge, this is the first time that mussels are successfully conditioned with formulated feeds.     

Are marine protected areas useful for the recovery of the Mediterranean mussel populations?

• 1. Mussel beds are important intertidal communities in the Mediterranean Sea and have traditionally been exploited by humans.
• 2. Marine protected areas are management tools for recovering over‐fished populations, normally top predator populations, which may in turn undermine prey abundance. Therefore, mussel populations might not recover inside protected areas, as they are affected by increasing fish populations.
• 3. To study the effects of both human and fish predation on mussels, three locations were selected: the Reserve (R), where all types of exploitation were banned and fish were abundant; the Partial Reserve (PR), where only angling was permitted, and fish abundance was low; and the Non‐Reserve (NR), where no protection existed and fish were rare.
• 4. Data from mussel bed surveys indicate that recruitment is critical to sustain mussel populations, and similar size structures were found at all three locations. However, the overall biomass in the PR was nearly double that in both R and NR, suggesting disturbance of some sort at these latter two sites.
• 5. A tethering experiment showed that fish predation greatly affected mussels in R, while the analysis of harvester collections from the NR showed that the most harvested size classes were those least abundant in the mussel bed.
• 6. Both protected and non‐protected areas are unable to increase mussel populations due to trophic cascade effects, while partial reserves, where fish populations are exploited and mussels protected, are areas where the Mediterranean mussel populations can recover.

Copyright © 2007 John Wiley & Sons, Ltd.     

东极厚壳贻贝养殖群体表型性状的相关与通径分析

[目的]为厚壳贻贝的选育工作提供理论指导.[方法]选取浙江省舟山市东极养殖区的厚壳贻贝作为研究对象,分别测量壳长(SL)、壳宽(SW)、壳高(SH)等10个形态性状以及总体重(GW)、壳重(KW)和软体重(RW)这3个重量性状,采用相关分析、多元回归分析和通径分析等方法探讨了形态性状对重量性状的影响.[结果]所测的表型性状之间均达到显著相关(P＜0.05),相关系数为0.233 ～ 0.975.建立了形态性状与总体重、壳重和软体重的回归方程,分别为GW=-34.511+ 10.058SH +5.844SW +2.121OC (R2=0.771);KW=-8.209+ 4.482SH+ 2.082SW (R2=0.771);RW=-9.549+ 2.274SH+1.648SW+1.025CD(R2=0.625).[结论]东极养殖区厚壳贻贝的人工选育可以壳高为选择目标,重视对壳宽的协同选择.     

紫贻贝消化系统的组织学和组织化学研究

对紫贻贝消化系统进行了组织学和组织化学研究。紫贻贝消化系统由消化腺－肝胰遥和消化道－食道、胃（包括晶杆囊）、肠和直肠组成。消化腺为复管腺,腺上皮有消化细胞和嗜碱性细胞两种类型。消化道管壁由粘膜层、粘膜下层和外膜组成,无肌层。粘膜上皮主要为单层柱状纤毛细胞。组织化学研究表明：消化嗜碱性细胞富含蛋白质和ＲＮＡ,消化细胞富含脂类和多种酶类：蛋白酶、非特异性酯酶、脂酶、酸性磷酸酶及碱性磷酸酶。消化道中酶的