家蝇抗菌活性物质研究进展

  目的  探讨家蝇幼虫体外分泌型溶菌酶的表达及分泌物抗菌抗炎活性。  方法  收集家蝇3日龄幼虫体外分泌物，通过聚丙烯酰胺凝胶电泳（SDS-PAGE）实验检测溶菌酶表达，并采用比浊法测定溶菌酶含量；用超滤管对分泌物进行纯化，得到分子量为10～30 kDa组分并进行抑菌曲线测定和细胞水平抗炎活性筛选。  结果  家蝇幼虫体外分泌物中存在溶菌酶，含量为（0.432 ± 0.01）μg/mg；家蝇幼虫体外分泌物中的10～30 kDa组分对大肠杆菌和金黄色葡萄球菌的生长均存在抑制作用；与对照组[（0.42 ± 0.02）μmol/L]比较，脂多糖组RAW264.7细胞中NO含量[（15.34 ± 2.05）μmol/L]明显升高，分泌物组RAW264.7细胞中NO含量[（7.32 ± 0.62）μmol/L]明显下降，表明家蝇幼虫体外分泌物中的10～30 kDa组分具有一定的抗炎功效。  结论  家蝇幼虫体外分泌物10～30 kDa组分中含有溶菌酶，具有抗菌抗炎活性。

Characterization and function of kuruma shrimp lysozyme possessing lytic activity against Vibrio species

  Objective  To investigate antibacterial and anti-inflammatory activities of secretory lysozyme from larvae of Musca domestic.  Methods  Secretions from the third instar larva of Musca domestic were collected; then the expression of lysozyme in the secretions was detected with sodium dodecyl-polyacryl gradient gel electrophoresis (SDS-PAGE) assay and the content of the lysozyme was measured with turbidimetry. The chemical components with the molecular weight (MW) of 10 – 30 kDa were purified from the secretion with millipore filter. The purifications' bacteriostasis against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was determined with bacteriostatic curve method and the anti-inflammatory activity was detected with RAW264.7 cells.  Results  The concentration of lysozyme in the secretions was 0.432 ± 0.01 μg/mg. Bacteriostatic curves of the secretions' components with MW of 10 – 30 kDa showed an inhibitory effect on the proliferation of both E. coli and S. aureus. Compared to that (0.42 ± 0.02 μmol/L) in the blank control, the concentration of nitric oxide (NO) in RAW264.7 cell culture fluid significantly increased to 15.34 ± 2.05 μmol/L in the lipopolysaccharide (LPS) group; while, the cell culture fluid NO concentration (7.32 ± 0.62 μmol/L) of the Musca domestic larvae secretion group was significantly decreased in comparison with that of LPS group, indicating the anti-inflammatory activity of secretion components with the MW of 10 – 30 kDa.  Conclusion  There is lysozyme in the secretory components with the MW of 10 – 30 kDa from larvae of Musca domestic and the components have antibacterial and anti-inflammatory activities.