Matrix metalloproteinase (MMP), a protease enzyme, participates in proteolytic cleavage of extracellular matrix proteins from Drosophila and mammals. But, recent studies have revealed other physiologically important roles of MMP in Drosophila. MMP contributes to cardioblast movement and distribution of collagen proteins during cardiogenesis in developing Drosophila. Tissue remodeling, especially tracheal development is also maintained by MMP. MMP regulates certain immunological functions in Drosophila such as wound repairing, plasmatocyte assemblage at the injured site of the basement membrane and glial response to axon degeneration in Drosophila nervous system. But, the contribution of MMP to tumor formation and metastasis in Drosophila has made it an interesting topic among researchers. Ovulation and egg laying are also found to be affected positively by MMP in Drosophila.

Acetylcholinesterase (AChE), an esterase enzyme, terminates synaptic transmission by hydrolyzing the neurotransmitter acetylcholine into acetate and choline. Found in membrane-bound form, AChE has also been reported to be secreted in soluble form by numerous enteric helminth parasites. Secretory AChE is considered to be an immunomodulator that may promote the survival of parasites against the host’s immune response. Our aim was to investigate the immunomodulation and survival strategy of helminth parasites Ascaridia galli inside the host Gallus gallus domesticus through analysis of AChE activity. The parasites, host intestinal tissue and post-secretory parasites were subjected to centrifugation, followed by AChE activity determination. The AChE activities among intestinal tissue, fresh parasites, excretory/secretory (E/S) product and post-secretory parasites were even compared. An inverse relationship between the reduced enzyme activity of the host’s intestinal tissue and the increased enzyme activity in the parasite was observed. Our study indicates that the increased AChE activities in fresh parasites, postsecretory parasites and E/S product are their survival strategy as well as a part of their adaptive features vis-à-vis the hostile environment of the host’sintestine.