Isolation and Partial Characterization of Proteins from the Mammillary Coat of Ascaris lumbricoides Fertilized Egg

Abstract

Background and Objectives: The Center for Disease Control (CDC) reported in 2013 that the worldwide prevalence of Ascaris lumbricoides infection is 20% of the world's population or a total of 2 billion. Its high prevalence is almost always associated with poor sanitary practices based on several epidemiological studies. Ascaris is usually diagnosed by examining and describing the morphology of the eggs. While it has extensively been described morphologically, few information have been reported about the eggs' biochemistry especially the macromolecular characteristics of their proteins found on the exterior covering. Unembryonated eggs that are passed out from stool are considered diagnostic stages, which aid in laboratory diagnosis and detection. Morphological examination of eggs is valuable but exploring the protein in their mammillary coat is worthwhile for the development of future diagnostic kits. This study, therefore, is aimed at isolating and partially characterizing the external proteins of the eggs' mammillary coating.

Methodology: Ascaris lumbricoides' fertilized corticated eggs from formalinized pooled fecal samples of infected individuals were collected by capillary catch method. Protein coat from the eggs were removed by vortex agitation of the samples in 5% sodium dodecyl sulphate solution followed by ammonium sulfate precipitation. Precipitated proteins were reconstituted in phosphate buffered saline and its molecular weight was determined using SDS-PAGE.

Results and Conclusion: Two distinct protein bands with molecular weights of 75 kilodaltons and 200 kilodaltons were detected. The 75 kDa protein was suspected to be the major constituent of the albuminoid coat while the 200 kDa proteins have not yet been previously identified.