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[en] Biosilicification in diatoms and sponges potentially promises physiological, mild reaction conditions for controlling silica structures at the nanometer scale. Since Sumper et al. had isolated catalytic peptides (i. e., silaffins) from diatoms, a number of polymers bearing tertiary amine or ammonium groups have been used as a counterpart of silaffins to biomimetically synthesize silica structures. We demonstrated a micropattern generation of silica on the solid substrate by a mussel- and diatom-inspired approach combined with a soft lithography. This method shows several advantages to apply for a wide range of materials without harsh reaction conditions. Moreover, it could allow us to give proper functionalities on silica layers via well-defined organosilane chemistry
[en] The abandoned mining area is known to contain high concentration of heavy metals and radionuclides that can be harmful to human and the ecosystem itself. Mussel families are commonly used as bio monitoring tools to monitor the environmental pollution. Therefore, Ligumia recta (Black Sandshell), locally known as kijing was used to act as biological indicators that help in monitoring the heavy metals and radionuclides level. This study was carried out in Kampung Gajah, Perak which known as ex-mining area. The objective of this study is to determine the concentrations of As, Cd, Pb, Hg, "2"3"8U, "2"3"2Th and "4"0K in Ligumia recta collected from two ex-mining lakes; Tasik Kapal Tujuh and Tasik Air Hitam. The samples were divided into three categories based on size. The flesh were separated from the shell, oven dried, ground, sieved and pelletizing before measured using Energy Dispersive X-Ray Fluorescence Spectrometer (EDXRF). The results show that the concentrations of heavy metals and radionuclides in the two lakes have significant differences, however there are no significant differences between the size of the samples (p>0.05). In addition, the concentrations were found to be higher at Tasik Kapal Tujuh compared to Tasik Air Hitam. This may be due to the size of the lakes and the acidity of water in the lakes. From the concentrations of the heavy metals and radionuclides, the exposure ingestion dose rate, health risk index (HRI) and radiological health risk were calculated to monitor the safety level in the Ligumia recta for human consumption. (author)
[en] Analysis of micronuclei, nuclear buds, bi-polynucleated and fragmented-apoptotic cells was performed in gills of blue mussels exposed for 3 weeks to sublethal concentrations of bisphenol A, diallyl phthalate (for the both nominal concentration 50 ppb) and to tetrabromodiphenyl ether-47 (nominal concentration 5 ppb). Fourteen specimens from each treatment and control group were used for the analysis. Our results demonstrated a significant increase in micronuclei frequency after the treatment with bisphenol A (P = 0.0243), diallyl phthalate (P = 0.0005) and tetrabromodiphenyl ether-47 (P < 0.0001; Mann-Whitney U-test). Induction of bi-nucleated (P = 0.0028), fragmented-apoptotic (P = 0.0004) cells and nuclear buds (P = 0.0101) was found in mussels exposed to tetrabromodiphenyl ether-47 while treatment with diallyl phthalate increased the level of fragmented-apoptotic cells (P = 0.0283). Bisphenol A was the only agent that resulted only in induction of micronuclei but not any other kind of nuclear injuries
[en] Full text: Twenty ropes with 400 Perna perna mussels seeds (3 cm shell size) were set-up on floating structures at Cabo Frio Island, Arraial do Cabo, approximately 100 km Northeast of Rio de Janeiro city. A rope was taken out on a monthly basis, and the shell sizes of one hundred seeds were measured. The haemolymph of ten male and ten female individuals was taken, and the same individuals were separated for 210Po/210Pb determination. After one year of monthly sampling, no clear correlation was observed between the 210Po concentration, mussel's age and weight. A mean 210Po concentration of 155 Bq kg-1, wet weight basis, was obtained, which is comparable with data reported in the literature. The radiation dose did not have any observable effect on the micronuclei frequency and DNA breaks in the mussels. This was probably due to the low dose rate, 0.02 mGy d-1, in comparison with the suggested potential dose limit of 10 mGy d-1. (author)
[en] Mytilus edulis were exposed to 17β-estradiol (E2) and the synthetic estrogens ethinyl estradiol (EE2) and estradiol benzoate (EB) for 10 days. Two exposures were performed to determine their effect on vitellogenin (VTG) and estrogen receptor 2 (ER2) mRNA expression at different stages of the reproductive cycle. Significant natural variation was not observed in VTG mRNA expression, though ER2 mRNA expression displayed significantly lower values during January, February and July compared with other times of the year. A significant increase in VTG and ER2 mRNA expression was observed in mussels exposed to estrogens at the early stage of gametogenesis. In contrast, mature mussels displayed no statistically significant change in the VTG or ER2 mRNA expression. The data presented suggests that the reproductive physiology of molluscs, in terms of VTG and ER2 mRNA expression, may be susceptible to damage by environmental estrogens at certain points in their gametogenesis process. - This study concerns vitellogenin and estrogen receptor mRNA expression in a mollusc and is relevant to those studying endocrine disruption in invertebrate species.
[en] To improve understanding of environmental tritium behaviour, the International Atomic Energy Agency (IAEA) included a Tritium and C-14 Working Group (WG) in its EMRAS (Environmental Modelling for Radiation Safety) program. One scenario considered by the WG involved the prediction of time-dependent tritium concentrations in freshwater mussels that were subjected to an abrupt increase in ambient tritium levels. The experimental data used in the scenario were obtained from a study in which freshwater Barnes mussels (Elliptio complanata) were transplanted from an area with background tritium concentrations to a small Canadian Shield lake that contains elevated tritium. The mussels were then sampled over 88 days, and concentrations of free-water tritium (HTO) and organically-bound tritium (OBT) were measured in the soft tissues to follow the build-up of tritium in the mussels over time. The HTO concentration in the mussels reached steady state with the concentration in lake water within one or two hours. Most models predicted a longer time (up to a few days) to equilibrium. All models under-predicted the OBT concentration in the mussels one hour after transplantation, but over-predicted the rate of OBT formation over the next 24 h. Subsequent dynamics were not well modelled, although all participants predicted OBT concentrations that were within a factor of three of the observation at the end of the study period. The concentration at the final time point was over-predicted by all but one of the models. The relatively low observed concentration at this time was likely due to the loss of OBT by mussels during reproduction.
[en] Microplastic has been confirmed as an emerging pollutant in marine environments. One of the primary environmental risks of microplastics is their bioavailability for aquatic organisms. Bivalves are of particular interest because their extensive filter-feeding activity exposes them directly to microplastics present in the water column. In the present study, we investigated microplastic pollution in mussels (Mytilus edulis) from 22 sites along 12,400 mile coastlines of China in 2015. The number of total microplastics varied from 0.9 to 4.6 items/g and from 1.5 to 7.6 items/individual. M. edulis contained more microplastics (2.7 items/g) in wild groups than that (1.6 items/g) in farmed groups. The abundance of microplastics was 3.3 items/g in mussels from the areas with intensive human activities and significantly higher than that (1.6 items/g) with less human activities. The most common microplastics were fibers, followed by fragments. The proportion of microplastics less than 250 μm in size arranged from 17% to 79% of the total microplastics. Diatom was distinguished from microplastics in mussels for the first time using Scanning Electron Microscope. Our results suggested that the numbers of microplastic kept within a relatively narrow range in mussels and were closely related to the contamination of the environments. We proposed that mussels could be used as a potential bioindicator of microplastic pollution of the coastal environment. - Highlights: • Microplastics varied from 0.9 to 4.6 items/g in Mytilus edulis. • M. edulis contained more microplastics in wild groups than farmed groups. • The most common microplastics were fibers. • Diatom was distinguished from microplastics in mussels. • Mussels could be used as a potential bioindicator of microplastic. - Microplastics varied from 0.9 to 4.6 items/g in wild and farmed Mytilus edulis from 22 sites along the coastal waters of China.
[en] The source of radionuclides in the Adriatic Sea is global fallout primarily from the Chernobyl accident in 1986 and indirectly from the rivers discharges. A monitoring program for radioactivity in the northern Adriatic Sea was conducted by determination 137Cs, 40K, 232Th (228Ra), 226Ra, 238U and 7Be in the tissues of mussels Mytilus galloprovincialis, in spring and autumn periods from 2008 to 2014. A comparison of radioactive contamination was made between three locations of the northern Adriatic Sea (Lim Bay, Rasa bay and Bakar bay) under significant fresh water discharges. In Lim Bay 137Cs activity concentrations in surface seawater were low (1.83 Bq/m"3). In mussels 137Cs activity concentrations (less than 0.3 Bq/kg dry weight) were below the detection limit at all locations. In the spring activity concentrations of 7Be in mussels were similar or greater than in autumn. In the autumn activity concentrations of 40K in mussels were higher than in the spring, while in 2011 and 2013 the situation was reversed. Activity concentrations of primordial radionuclides 232Th (228Ra), 238U and 226Ra in mussels were mostly below the detection limit with no seasonal changes. Increased activity concentrations of individual radionuclides in the mussels tissues proved the exceptional ability of seawater filtration and indicator potential of these organisms. The activity concentrations of radionuclides in the northern Adriatic Sea have returned to the pre-Chernobyl level, generally taking into consideration their natural fluctuations due to the physico - chemical and hydrological parameters of the investigated area. (author).
[en] Animals in poor health condition are not relevant biological models. The current study focused on the use of the clearance rate of Mytilus edulis to assess the gross physiological condition of individuals maintained in stressful experimental conditions. This approach was developed in a new, highly controlled experimental exposure device designed to investigate individual responses in aquatic ecotoxicological studies. Both clearance rate values and immune parameters analysis indicated that the health condition of mussels kept in 50 ml tubes for 24 h or 48 h was not altered compared to controls, while most parameters were depressed after 72 h. Moreover, this study confirms the relevance of flow cytometric for the measurement of clearance rate compared to techniques utilizing microscopy. Current results prompted us to perform further 24 h chemical exposure using this 'in tubo' device. - Test-tube mussels offer a new exposure design for immunotoxicology
[en] A new Reference Material (RM) for radionuclides in mussel (Mytilus galloprovincialis) from the Mediterranean Sea (IAEA-437) is described and the results of the certification process are presented. Four radionuclides (40K, 234U, 238U, and 239+240Pu) have been certified, and information values on massic activities with 95% confidence intervals are given for nine radionuclides (137Cs, 210Pb(210Po), 226Ra, 228Ra, 228Th, 230Th, 232Th, 235U, and 241Am). Results for less frequently reported radionuclides (90Sr, 129I, 238Pu, 239Pu, and 240Pu) are also reported. The RM can be used for quality assurance/quality control of the analysis of radionuclides in mussel samples, for the development and validation of analytical methods and for training purposes. The material is available in 200 g units. (author)