An Evaluation of SDS-Polyacrylamide Gel Electrophoretic Analysis for the Determination of Intrageneric Relationships of Vairimorpha Isolates

Abstract

Extracts of hydrophilic exosporal proteins of three described species and three undescribed isolates of microsporidia of the genus Vairimorpha were studied by SDS-polyacrylamide gel electrophoresis. The protein profiles from the six isolates consisted of peptide bands ranging in number from 23 to 30. The relative mobilities of the bands were compared between isolates and coefficients of similarity were calculated. Two distinct groups were apparent: Vairimorpha necatrix, Vairimorpha plodiae, Vairimorpha heterosporum , and an undescribed isolate from the lepidopteran Heliothis armigera formed a related group, while the microsporidian isolates from the lepidopterans Alabama argillacea and Utethesia bella were more related to each other than to the former group. The reliability, however, of similarity coefficients as indicators of species relatedness appears to be questionable as the value is dependent on the number of bands detectable. Other techniques may be more useful for determining intrageneric relatedness than SDS-PAGE.