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.

Cockroaches are insects of the order Blattodea, sometimes also called Blattaria, of which about 30 species out of 4,600 total are associated with human habitats. About four species are well known as pests. Among the best-known pest species are the American cockroach, Periplaneta americana, which is about 30 mm long; the German cockroach, Blattella germanica, about 15 mm long. We researched growing condition of in-vitro(temperature and humidity) for P. americana and B. germanica. The cockroach is divided in three sections; the body is flattened and broadly oval, with a shield-like pronotum covering its head. A pronotum is a plate-like structure that covers all or part of the dorsal surface of the thorax of certain insects. They also have chewing mouth parts, long, segmented antennae, and leathery fore wings with delicate hind wings. The third section of the cockroach is the abdomen. We measured size of head, abdomen, and body length during differential stages. Also, we checked number of egg, size of egg, hatching rates, period of former laying eggs, and laying periods etc.

Vitellogenins (Vgs) are precursors of the major egg storage protein, vitellin (Vn), in many oviparous animals. Insects Vgs are large molecules (200-kD) synthesized in the fat body in a process that involves substantial structural modifications (e.g., glycosylation, lipidation, phosphorylation, and proteolytic cleavage, etc.) of the nascent protein prior to its secretion and transport to the ovaries. However, the extent to which Vgs are processed in the fat body varies greatly among different insect groups. We were cloned Vgs partial genes PaVgs and BgVgs from Periplaneta americana and Blattella germanica. Real-time quantitative PCR shows that PaVgs and BgVgs were differential-regulated with aging. In insects, glutathione S-transferases (GSTs) are enzymes involved in detoxification of insecticides. We were cloned GST partial genes PaGST and BgGST from Periplaneta americana and Blattella germanica. Real-time quantitative PCR shows that PaGST and BgGST were up-regulated with aging, and the mRNA level of PaGST and BgGST was higher in 4℃ and 37℃ than room temperature. The expression level of PaGST and BgGST exposure to temperature stress suggests that PaGST and BgGST are up-regulated after exposure low and hige temperature treatments.

Olfactory sensitivity exhibits daily fluctuations. Several studies have suggested that the olfactory system in insects is modulated by both biogenic amines and neuropeptides. However, molecular and neural mechanisms underlying olfactory modulation in the periphery remain unclear since neuronal circuits regulating olfactory sensitivity have not been identified. Here, we investigated the structure and function of these signaling pathways in the peripheral olfactory system of the American cockroach, Periplaneta americana, utilizing in situ hybridization, qRT-PCR, and electrophysiological approaches. We showed that tachykinin was co-localized with the octopamine receptor in antennal neurons located near the antennal nerves. In addition, the tachykinin receptor was found to be expressed in most of the olfactory receptor neurons in antennae. Functionally, the effects direct injection of tachykinin peptides, dsRNAs of tachykinin, tachykinin receptors, and octopamine receptors provided further support for the view that both octopamine and tachykinin modulate olfactory sensitivity. Taken together, these findings demonstrated that octopamine and tachykinin in antennal neurons are olfactory regulators in the periphery. We propose here the hypothesis that octopamine released from neurons in the brain regulates the release of tachykinin from the octopamine receptor neurons in antennae, which in turn modulates the olfactory sensitivity of olfactory receptor neurons, which house tachykinin receptors.