Study On The Nuchal Gland Of Rhabdophis Tigrinus Lateralis And Its Venom

Rhabdophis tigrinus, one of the colubridae, has no tubular rear-fanged teeth. It was demonstrated that this snake has two kinds of glands to produce venom, including Duvernoy gland located in the oral upper part, and nuchal glands distributed under the neck-back skin. Since Duvernoy gland was characterized as an venomous organ of this snake, a lot of papers were published about it's tissue structure, cell composition, properties and compositions of secreted venom as well as immunological properties. However, the study on the nuchal glands of Rhabdophis tigrinus yet remain to further be probe, especially the biochemical properties of secreted venom from the nuchal glands of Rhabdophis tigrinus laterlis.So, in this paper, we presented the study on the tissue structure of the nuchal glands and on the properties and components of the venoms from the nuchal glands. The main research works are as follows:1. Eight to thirteen pairs of nuchal glands were arranged in parallel, and each gland was in a shape of sphere like a pearl and isolated one another, and the nuchal glands had no ducts.2. The physical and chemical properties and the biological activities of the venom from the nuchal glands were determined, and the results indicated that the venoms were neurotoxic to mice (LD50 was 97.99 mg/kg), contained 87 % proteins by the Lowry method, and presented many bands of protein on SDS-PAGE. The venom hydrolyzed gelatin and casein, but the proteolytic activity was inhibited by EDTA. These results indicated it was possible to have metalloproteinase in the venom from the nuchal glands of Rhabdophis tigrinus laterlis. The other properties of the venom were measured. When the dosage of the venoms was up to 1 mg/ml, there were no activities of PLA, 5'-nucleotidase, alkaline phosphomonoesterase and phosphodiesterase in the venom; besides when the dosage of the venoms was up to 10 mg/ml, there were no coagulation or hematolysis activity in the venom. The antimicrobial experiments presented that the venom had not broad activities of antibiosis,and it just weakly influenced Streptococcus thermophilus and Bnfillus licheniformis (minimal inhibitory concentration was 12.5 mg/ml, inhibition zone was 6 mm and 8 mm respectively).3. A metalloproteinase with 81 KDa was isolated and purified from the venom by the way of ion-exchange chromatography and gel filtration chromatography. It exhibited only one band on SDS-PAGE, its hydrolytic activity was 0.56 U/mg when it hydrolyzed casein, its maximum pH was 8, and its maximum temperature was 40℃; EDTA, EGTA,β-mercaptoethanol could inhibit its hydrolytic activity, PMSF weakly inhibited its activity, K+ significantly inhibited its activity, Ca2+ and Zn2+ inhanced its activity. There were no activities of PLA, 5'-nucleotidase, alkaline phosphomonoesterase and phosphodiesterase, and no fibrinogenlytic activity and coagulation activity in the venom. Animal experiment indicated there was no hemorrhagic activity in the venom .In a brief, in this paper, the nuchal glands of Rhabdophis tigrinus laterlis and its venom were first reported, and a metalloproteinase was isolated and purified and its properties were measured .