Résumé
Mytilus is a bivalve species with important economic and ecosystem value over worldwide. Mytilus antimicrobial peptides‚ with strong molecular diversity‚ has become a research focus. Two novel antimicrobial peptides were identified from Mytilus‚ with structural features that similar to arthropod defensins. However‚ the functional features and the immune mechanism of these two mussel defensins are unknown. For this reason‚ the two novel defensins‚ Arthropod like defensn-1 and -2 (ALD-1 and ALD-2‚ respectively)‚ were studied for the sequence features‚ expression profiles‚ and the dynamic expression pattern after different microbe induction. In addition‚ solid phase chemical synthesis technology was used for the synthesis of these two novel ALDs‚ and the function of synthesized peptides of ALD was verified. The results indicated that‚ two ALDs of M. coruscus have classical structure features similar to those of other arthropod defensins. These two ALDs are mainly presented in the tissues of mantle and digestive gland of mussel. The results also suggest that ALD-1 was expressed at higher levels in the gonads of males than in females (P<0. 05). The expression of two ALDs is developmentally regulated‚and both ALD-1 and ALD-2 were undetectable in larvae‚ but can be detected with high expression level at adult mussel with age of six months. The dynamic changes in the expression level of two ALDs after microbial induction were examined‚ and the results showed a marked increase in expression level observed in vivo for both ALDs. Interestingly‚ two ALDs showed different sensitivities to different microbes‚ indicating very complex responses during the mussel immune response. This observation strongly suggests the existence of different recognition mechanism or signal transduction pathway in mussels for the expression of ALD-1 and ALD-2. Moreover‚ both of two chemical synthesized ALDs showed significant antimicrobial activities against five tested microbes with an inhibition ratio of 20%-80%. These results provided basis for understanding the molecule mechanism of Mytilus immunology‚ and the function of novel Mytilus defensins‚ and thusly provided basis for the development of molecular resource for mussel antimicrobial peptides.
Résumé
The ornithine-urea cycle (OUC) plays important roles in metabolism. However, there is a lack of study of OUC in shellfish. For filling this gap, the mussel Mytilus coruscus was selected, and the key genes together with the metabolites of OUC pathway were analyzed in the mantle and adductor muscle, respectively, using a real-time fluorescent quantitative PCR and an amino-acid analyzer. Moreover, the changes of the metabolite concentrations and the gene relative expression level of OUC were analyzed after arginine injection. The δ
Résumé
In this studies, an anticancer peptide was isolated from the enzymatic hydrolysate of Mytilus coruscus.CCK-8 assay was used as guide in activity screening through the isolation process of membrane filtration, DEAEsepharose chromatography, Sephadex G-25 exclusive chromatography and RP-HPLC. An anticancer peptide was obtained and identified as Asp-Leu-Tyr.
Résumé
Objective: To investigate the anti-aging activity of Mytilus coruscus polysaccharide (MP) in aged rats. Methods: We established a 24-month natural aging rat model. Twenty model rats were divided into 4 groups, namely, the aging model group, Mytilus coruscus powder group (MCP 1 g/kg), high dose MP group (MP 400 mg/kg), and low dose MP group (MP 200 mg/kg). Five three-month-old rats served as young control. The Mytilus coruscus power solutions and MP solutions were given intragastrically on a daily basis for 90 days. The organ indices of the heart, liver, kidney, and spleen of rats were observed; the pathology of the hearts and livers was also observed. The levels of superoxidedismutase (SOD), glutatio-neperoxidase (GSH-Px), and malonaldehyde(MDA) in the serum and liver were determined; and the main serum parameters were also determined. Results: Compared with the aging model group, the heart and liver pathology had no obvious aging changes in the high dose MP group. The serum and liver SOD, GSH-Px levels were significantly higher in the high dose MP group than those in the aging model group (P<0.01); the MDA level was significantly lower than those in the aging model group (P<0.01). Conclusion: The Mytilus coruscus polysaccharide possess anti-aging activity, and the anitoxidative effect might be one of the mechanism for the anti-aging effect.
Résumé
80%)as a calcium supplement.Methods Weanling SD rats(21 days after birth,n=50)were fed with low calcium forage for 10 days,then were divided into 5 groups randomly with 10 rats in each group,half male and half female.GroupⅠwas control group fed on low calcium forage.GroupⅡ~Ⅲ were fed on low calcium with L-lactic acid calcium.Group Ⅳ~Ⅴ were fed on low calcium forage with ultramicro-mussel shell powder.The experiment period was 4 weeks.The indices were including the eventual weight and length of the rats,the calcium absorption rate of calcium supplement,the concentrations of serum calcium,serum phosphorus,bone calcium,skeletal muscle calcium,myocardial calcium,hemocyte calcium,liver calcium,kidney calcium and the activity of alkaline phosphatase were assessed.Results The effect of ultramicro-mussel shell powder group was similar to L-lactic acid calcium.Conclusion The ultramicro-mussel shell powder can be well absorbed and utilized,and it can be used as a calcium supplement.