Composition Of The Defensive Secretion Of Blaps Femoralis And Preparation Of Chintin

Blaps femoralis (Fischer von Waldheim,1844), a semi-social insect, is dominant soil beetle in Northern China. The B. femoralis is widely used in Chinese traditional medicine as a medicinal material. Because the body contains medicinal and nutritional materials richly, it has a great potential to develop. Especially its defense gland secretion, which is normally used for defense and aggregation in daily activities, is toxic. The dissertation completed in thirty thousand characters. After summarzing different researches comprehensively, e.g. nutrition, we focus on the chemical compositions as well as the antibacterial activity of its defensive secretion, and chitin extraction from B. femoralis. Main achievements obtained as followings:1. By combined gas chromatography-mass spectroscopy (GC-MS) analysing, it showed the defensive secretion of B. femoralis contained 14 kinds of compounds. Three major compounds were 2-methyl-p-benzoquinone,1-tridecene, and 1-(2,4-dimethylfuran-3-yl)-ethanone. The remaining compounds with relative lower amount were identified as p-benzoquinone, hydroquinone,3,5-dihydroxytoluene, and dodecanal. In addition, no protein was detected in its defensive secretions. The above study is a foundational research to help us revealing the bacteriostatic action mechanism of the defensive secretion of B. femoralis. It also confirmed its medicinal value.2. We studied the bacteriostatic effect on five kinds of bacteria and four kinds of fungi. The results showed the inhibiting effect of defensive secretion to gram-positive bacterium is more significant than to gram-negative bacterium. The minimum inhibitory concentration of defensive secretion on Staphylococcus aureus is 4μL/mL.3. Chitin was extracted from B. femoralis by acid-base treatment. The average unit yield reaches up to 29.6 percent, which is higher than the productivity from shells of shrimp and crab. Chitosan is the deacetylated product of chitin. The degree of deacetylation in such chitosan production is 80.5%, viscosity-average molecular weight 3.32×105, and it's white crystal. This study provides a significant evidence to comprehensively utilize this resource in future.