The Organ Distribution, Characterization and Modification of Acetylcholinesterase Activity in Adult African Grasshopper: Zonocerus sp Linn.

Abstract

Aim: To determine the organ distribution and characterization of acetylcholinesterase in the adult African variegated grasshoppers – Zonocerus variegatus and Zonocerus elegans. (Zonocerus Sp. Linn) Place and Duration of the Study: The insect model: African variegated grasshoppers are gotten from the Open green fields at the Federal University of Technology, Akure, Nigeria, and research was carried out between March and June, 2016 in the Enzymology laboratory, Biochemistry department, Federal University of Technology, Akure, Nigeria. Methodology: Twenty (20) adults variegated grasshoppers were taken from the Open field in the University community, and taken to the Biology department for Identification. After identification, the specimen was weighed, freeze, dissected into fractions (Head, Thorax and Abdomen) and then homogenized to get the crude protein extract. The crude enzyme extract is further purified using the Ion-exchange chromatography with column bed packed with DEAE – Sephadex A50. The protein content of the purified AChE was determined using the Lowry method while the Acetylcholinesterase activity was determined by the Ellman’s assay procedures. The characterization of AChE was tested by modifying agent such as N-Bromo Succinamide (NBS) which confirms the presence of key aromatic proteins involve in catalysis at the active site of the enzyme. Results: The protein concentration according to their fractions: Head (35.7%), Thorax (29.2%), and Abdomen (35.1%). The AChE activity according to their fractions: Head (38.6%), Thorax (23.7%), and Abdomen (37.7%). The specific activity which relates the AChE activity to protein content is given: Head (28.8%), Thorax (40.4%), and Abdomen (30.8%). From the Organ distribution and AChE activity, it was observed that the Head Fractions has the Highest protein content, and Enzyme activity. Comparatively, there are slight differences in the Enzyme activity of the Head and Abdominal fractions which represents the two peaks in the AChE chart. As well, the thorax has the highest specific activity. The modification by the chemical agent NBS shows a drastic decrease (about 50%) in Enzyme activity and characterize enzyme active site with aromatic proteins especially tryptophan residues. Conclusion: Research findings shows the dominance of AChE protein in the Head region, hence high enzyme activity (useful for nervous coordination) as well as presence of tryptophan residues at the enzyme active site. The importance of research is useful in enzymology, neuroscience and public health.