An active biomonitoring study was carried out on the Algerian west coast using wild reference mussels (Mytilus galloprovincialis) sampled from the Kristel (K) site and transplanted in net cages during one month (between May and June 2007) to Oran Harbour (OH) and Mostaganem Harbour (MH), areas characterised by high levels of urban and industrial pollution. The biological response of the mussels was evaluated by their condition index and the use of a general stress biomarker (evaluation of lysosomal membrane stability: the neutral red retention time (NRRT) method), a genotoxic effects biomarker (determination of micronuclei (MN) frequency) and a neurotoxic effects biomarker (determination of the acetylcholinesterase (AChE) concentration). Compared to the K reference specimens, OH and MH caged mussels presented a significant decrease of NRRT in lysosomal haemocytes (56.45±26.48 min and 67.25±22.77 min, respectively) (78±16.97 min for K mussels), an MN frequency respectively 7.3 and 9 times higher in the haemocytes and the gill cells of the OH caged mussels, and 7.2 and 6.4 times higher in the two tissues of the MH caged mussels. Significant inhibition of AChE activity was noted in the gills (16.93±3.1 nmol min−1 mg prot−1) and the digestive gland (7.69±1.79 nmol min−1 mg prot−1) of the OH mussels, but only in the gills (23.21±5.94 nmol min−1 mg prot−1) of the MH mussels, compared to the organs of the K control specimens (35.9±6.4 nmol min−1 mg prot−1 in the gills and 11.17±0.49 nmol min−1 mg prot−1 in the digestive gland). This study reflects the interest in such in situ biomonitoring assays and the utility of these biomarkers for assessing the effects of pollution in the Algerian coastal marine environment.
Diets supplemented with Mytilus galloprovincialis from polluted and non-polluted waters and their influence on zinc content in liver of rats loaded with cholesterol. Mussels may reflect the environmental problems that the ecosystem faces. Mytilus galloprovincialis is widely used as an indicator of water pollution in biological monitoring studies. These mussels are filter feeders and may accumulate important ecosystem pollutants what in turn may pose a potential risk to other organisms in the food chain. The aim of the study was to determine zinc content in the diets supplemented with mussels from polluted and non-polluted areas and in the livers of rats fed these diets for 30 days. The zinc content in the diets with mussels from contaminated and noncontaminated waters and in rat livers was examined using a flame atomic absorption spectrophotometry (Perkin-Elmer 1100B). The slight increase in zinc content from 73.2 ±1.2 mg/ /kg in ch diet (control with 1% of cholesterol) to 77.2 ±0.5 mg/kg in the diet with mussels from polluted site was found, but zinc content in all diet was within the normal limits reviewed by McDowell (1992) – 40 to 100 ppm. Zinc content in the diet supplemented with mussels from nonpolluted site (73.7 ±3.7 mg/kg) was similar to that found in ch diet. It can be concluded that cholesterol does not affect zinc bioaccumulation. However, prolonged consumption of mussels from contaminated sites may increase accumulation of zinc in the liver of rats.
Mitochondrial genomes are frequently used to infer phylogenetic relationships. Some taxa are, however, poorly represented. To facilitate better understanding of the potential of mitochondrial genome data in freshwater mussels, we present here, for the first time, the mitochondrial sequences of 4 complete F-type mitochondrial genomes from the European freshwater bivalve Unio pictorum (Unionidae). These genomes are very compact (15 761 bp) but have atypical gene complement for bilaterian mitochondrial genomes and a very similar organization to other unionid genomes available in databases. Very low nucleotide diversity within the species suggests a small effective population size of Polish U. pictorum, a phenomenon of potential importance for environmental management policies.