Cloning and Characterization of Antibacterial Genes in Periplaneta americana and Blattella germanica

다국어 초록 (Multilingual Abstract)

Lysozyme was the first humoral antibacterial factor to be studied in insects and it was considered the main immune factor in the haemolymph. Lysozymes are enzymes characterized by their ability to break down bacterial cell walls. We identified four lysozymes(c1, c2, c3, and I type)-encoding cDNAs from P. americana. It was deduced protein sequences are basic in nature, contain 138 amino acids(c1), 139 amino acids(c2), 141 amino acids(c3), and 143 amino acids(I) including conserved cysteine residues. Transcriptional profiles indicated that the predominant form is constitutively expressed and up-regulated upon immune challenge by heat stress. When injected lipoplysaccharide (LPS), lysozymes (I, c1, and c2) was up-regulated in the body. In addition, the expression levels of lysozymes(I, c1, and c2) in the P. americana significantly increased after two hour by injection of LPS. We were cloning and analysis of chitinase from B. germanica. The chitinase was deduced protein sequences are contain 539 amino acid residues long. The chitinase were up-regulated by injection of LPS in B. germanica. the expression levels of chitinase in the B. germanica significantly increased after four hour by injection of LPS. The cDNA encoding the chitinase of B. germanica was expressed as a 67-kDa band in the baculovirus-infected insect cells and the extracts of the recombinant baculovirus-infected cells showed anti-bacterial activity(0.0125㎍/㎖: 2.5±0.3, 0.00125㎍/㎖: 0.6±0.4mm) to C. albican on the plate.