ABSTRACT
Objective To evaluate the effects of Cu2+ and Cd2+ at different concentrations on superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity in Oncomelania hupensis. Methods Cu2+- and Cd2+-containing solutions were prepared at 7 concentrations, and O. hupensis snails were exposed to the solutions for 24 h, of 15 snails in each concentration. Then, the snail body was collected following removal of the snail shell and homogenated, and the SOD, CAT and POS activities were detected in the supernatants. Results With the increase of the Cu2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline-rise-decline tendency, while the POD activity showed a tendency towards rise followed by decline. With the increase of the Cd2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline- rise- decline tendency, while the POD activity showed a decline-rise-decline tendency. Conclusion Exposure to Cu2+ and Cd2+ at high concentrations results in a decline in the activity of SOD, CAT and POD in O. hupensis at the same time.
ABSTRACT
Objective To assess the acute toxicity of Cu2+, Cd2+, Hg2+ and Pb2+ to Oncomelania hupensis. Methods Cu2+, Cd2+, Hg2+ and Pb2+ solutions were prepared at five concentrations, and 10 snails were exposed to each concentration for 24, 48, 72 h and 96 h. Then, the inhibition of snail activity and snail death was observed, and the half maximal effective concentration (EC50) and median lethal concentrations (LC50) were estimated. Results The 24, 48, 72 h and 96 h EC50 values of Cu2+, Cd2+, Hg2+ and Pb2+ were 0.74, 0.56, 0.46, 0.37 mg/L, 4.79, 3.52, 1.70, 1.26 mg/L, 1.90, 1.49, 0.83, 0.76 mg/L and 21.40, 9.98, 7.90, 5.42 mg/L for snails, respectively. The 96 h LC50 values of Cu2+, Cd2+, Hg2+ and Pb2+ were 0.43, 2.96, 1.12 mg/L and 12.22 mg/L for snails, the safe concentrations were 0.004 3, 0.029 6, 0.011 2, 0.122 2 mg/L, respectively. Conclusion Cu2+ shows a high acute toxicity to snails, and Cd2+ and Hg2+ exhibit a moderate acute toxicity to snails, while Pb2+ is lowly toxic to snails.
ABSTRACT
Objective To study the differences of the phenoloxidase (PO) relative activity among ribbed shelled Oncomelania hupensis, smooth shelled O. hupensis and Cipangopaludina chinensis. Methods The crude PO fluid was extracted from the soft tissue of O. hupensis and C. chinensis by homogenation and centrifugation. The PO activity was detected with catechol as the substrate in the reaction systems. Results The PO relative activities in the ribbed shelled O. hupensis, smooth shelled O. hupensis and C. chinensis were (25.72 ± 2.27), (14.56 ± 1.24) U / mL and (13.72 ± 1.06) U / mL. The PO relative activity in the smooth shelled O. hupensis was higher than that in the ribbed shelled O. hupensis (q = 21.46, P < 0.05) and C. chinensis (q = 12.00, P < 0.05), while the difference between the PO relative activities of the latter two was not statistically significant (q = 1.62, P > 0.05) . Conclusion There is a difference in the relative PO activity between O. hupensis and C. chinensis, which may be related to the living environment of snails.
ABSTRACT
Objective To detect the molecular characterization of polysaccharide purified from Amusium pleuronectes, so as to investigate its role of intervention to the formation of hepatic fibrosis caused by Schistosoma japonicum infection. Methods The crude polysaccharide from A. pleuronectes was extracted and further purified, and the molecular weight and monosaccharide composition were determined by the high pressure size exclusion chromatography and PMP pre-column derivatization method, respectively. A total of 50 female BALB/c mice were randomly divided into five groups：A (normal group), B (experimental group), C (polysaccharide group), D (praziquantel), and E (polysaccharide + praziquantel group). The mice in B, C, D, or E groups were attacked on the abdominal skin by using the cercariae of S. japonicum (30 ± 2 for each mouse) respectively. After 8 weeks, the mice in C, D, and E groups were administrated by polysaccharide and/or praziquantel, and the mice in B group were instead of saline. All the livers and sera were collected after 16 weeks. HE staining was employed for the livers, and serum IFN-γ and IL-13 were measured by using ELISA kits. Results The molecular weight of purified polysaccharide from A. pleuronectes was 11.7 kDa. Compared with A and B groups, the serum levels of IFN-γ in C, D, and E groups were significantly increased (F = 63.525, P < 0.01). However, the serum levels of IL-13 in C, D, and E groups were significantly decreased (F = 99.788, P < 0.01) compared with that in B group. HE staining showed that the egg nodules and hepatic fibrosis were observed in B, C, D, and E groups. The number of egg nodules and fibrosis degree in E group were milder than those in B group (χ2 = 7.875, P < 0.05). Conclusions The polysaccharide from A. pleuronectes has an obvious effect in preventing hepatic fibrosis process induced by S. japonicum infection, particularly combining with the administration of praziquantel.
ABSTRACT
Objective To study the differences of the phenoloxidase (PO) relative activity among ribbed shelled Oncomelania hupensis, smooth shelled O. hupensis and Cipangopaludina chinensis. Methods The crude PO fluid was extracted from the soft tissue of O. hupensis and C. chinensis by homogenation and centrifugation. The PO activity was detected with catechol as the substrate in the reaction systems. Results The PO relative activities in the ribbed shelled O. hupensis, smooth shelled O. hupensis and C. chinensis were (25.72 ± 2.27), (14.56 ± 1.24) U / mL and (13.72 ± 1.06) U / mL. The PO relative activity in the smooth shelled O. hupensis was higher than that in the ribbed shelled O. hupensis (q = 21.46, P < 0.05) and C. chinensis (q = 12.00, P < 0.05), while the difference between the PO relative activities of the latter two was not statistically significant (q = 1.62, P > 0.05) . Conclusion There is a difference in the relative PO activity between O. hupensis and C. chinensis, which may be related to the living environment of snails.
ABSTRACT
Objective To detect the molecular characterization of polysaccharide purified from Amusium pleuronectes, so as to investigate its role of intervention to the formation of hepatic fibrosis caused by Schistosoma japonicum infection. Methods The crude polysaccharide from A. pleuronectes was extracted and further purified, and the molecular weight and monosaccharide composition were determined by the high pressure size exclusion chromatography and PMP pre-column derivatization method, respectively. A total of 50 female BALB/c mice were randomly divided into five groups：A (normal group), B (experimental group), C (polysaccharide group), D (praziquantel), and E (polysaccharide + praziquantel group). The mice in B, C, D, or E groups were attacked on the abdominal skin by using the cercariae of S. japonicum (30 ± 2 for each mouse) respectively. After 8 weeks, the mice in C, D, and E groups were administrated by polysaccharide and/or praziquantel, and the mice in B group were instead of saline. All the livers and sera were collected after 16 weeks. HE staining was employed for the livers, and serum IFN-γ and IL-13 were measured by using ELISA kits. Results The molecular weight of purified polysaccharide from A. pleuronectes was 11.7 kDa. Compared with A and B groups, the serum levels of IFN-γ in C, D, and E groups were significantly increased (F = 63.525, P < 0.01). However, the serum levels of IL-13 in C, D, and E groups were significantly decreased (F = 99.788, P < 0.01) compared with that in B group. HE staining showed that the egg nodules and hepatic fibrosis were observed in B, C, D, and E groups. The number of egg nodules and fibrosis degree in E group were milder than those in B group (χ2 = 7.875, P < 0.05). Conclusions The polysaccharide from A. pleuronectes has an obvious effect in preventing hepatic fibrosis process induced by S. japonicum infection, particularly combining with the administration of praziquantel.
ABSTRACT
Objective To study the lysozyme activity in Oncomelania hupensis and observe its inhibitory effect on bacterial growth.Methods Soft tissues of Oncomelania hupensis were initially homogenized and immersed in Tris-HCl-TritonX-114 buffer solution for 24 hours then the supernatant was collected after centrifugation at 10 000 × g for 10 minutes.The supernatant was incubated in a 37 ℃ water bath for 15 minutes and centrifuged again at 2000 × g for 10 minutes.The precipitate was put into ultrafiltration tube (relative retention molecular mass =3000) and centrifuged at 4 ℃,5 000 × g for 30 minute to obtain concentrated enzyme.The protein content,lysozyme activity and the antibacterial effect on Micrococcus lysodeikticus,Shigella dysenteriae,Staphylococcus aureus,Escherichia coli and Candida albicans were measured with bicinchonininc acid(BCA) method,turbidimetric method and agar diffusion (K-B) method,respectively.Results The antibacterial protein lysozyme was identified in gastropod protein concentration of the concentrated enzyme was 3.428 g/L.Average activity,total activity,and specific activity were (760 ± 120) × 103 U/L,(1520 ± 240) × 103 U/L and (221.70 ± 35.00)U/mg,respectively.The enzyme had produced exclusive inhibitory effects on growth of Micrococcus lysodeikticus and Shigella dysenteriae.Average inhibitory diameters were 10-12 and 12-15 mm,respectively.No inhibition zone was observed in saline control,Staphylococcus aureus,Escherichia coli and Candida albicans.Conclusions Lysozyme can be extracted from soft tissues of Oncomelania hupensis with Tris-HCl-TritonX-114 buffer solution,and the enzyme has inhibitory effect on growth of Micrococcus lysodeikticus and Shigella dysenteriae but has no antibacterial effect on Staphylococcus aureus,Escherichia coli and Candida albicans.