Effect of fertilizers on haemmocyanin (the oxygen binding protein in snail)

Abstract

Giant African snails (Achatina achatina) uses haemocyanin as their oxygen binding protein. Haemocyanin is a copper containing protein present in the animal’s haemolymph. It binds and transports oxygen and can exist in two conformations viz oxy-haemocyanin and deoxyhaemocyanin depending on the availability of oxygen. This work examines the effects of two fertilizers (NPK 20:10:10 and Urea) on haemocyanin. In the preliminary experiment results in which the environmental effect of these fertilizers on Achatina achatina were carried out revealed a negative change in function consequent upon weight loss and death. Haemocyanin
on reacting with ions such as those contained in the fertilizers for example nitrogen ion looses its function due to conversion to met-haemocyanin which has a reduced oxygen affinity. In determining the molecular cause of death in Achatina achatina, various concentrations of both fertilizers were reacted with purified haemocyanin and the spectra of the mixture read. Result
showed significant decrease in the magnitude of absorbance maxima as compared to normal control. The decrease suggests that haemocyanin’s oxygen binding affinity decreased. Varying the amount of fertilizers was to determine if concentration has any effect. In comparing the results of the different concentrations, observation was made that as the concentration of fertilizer increased, the absorbance decreased. Fertilizers therefore affects the pathophysiology of Achatina achatina by disrupting the activity of its oxygen carrier leading to a diseased condition and eventual death.
Keywords: Effect of NPK fertilizer; African Giant snail; Haemocyanin