Poster Presenter

Studies on the in vitro Spermicidal Activity of Sperm Immobilization Factor Isolated from Escherichia Coli: A Potential Candidate for Fertility Control
Kiranjeet Kaur, Vijay Prabha, Ravneet Sandhu, Siftjit Kaur, Vijay Kumar
India

Escherichia coli is one of the most frequent microorganism isolated from the semen with the most negative influence on sperm motility and morphology. Although several research groups have outlined the negative influence of various E. coli strains on motility and motility parameters of human spermatozoa in in vitro experiments but the mechanism of this immobilization has not been elucidated. We have undertaken an investigation into the mechanism of how bacteria immobilize spermatozoa. This report confirms the immobilization of spermatozoa by E. coli and demonstrates a sperm immobilization factor (SIF), excreted by E. coli which immobilizes spermatozoa. Further an attempt was made to isolate and purify SIF. The factor from 72 h old culture supernatant was purified to homogeneity by ammonium sulphate precipitation, gel permeation chromatography and ion exchange chromatography. The purified factor (56 kDa) not only had a remarkable sperm immobilizing activity, it had a spermicidal effect also. Spermatozoa immobilized by SIF after removing the SIF and resuspended in buffer did not gain motility indicating that this phenomenon is irreversible. Electron microscopic analysis of spermatozoa-SIF interactions revealed multiple and profound alterations in the morphological structures of spermatozoa indicating that these morphological defects might be accounting for the immobilization of spermatozoa by E. coli. In conclusion it may be stated that SIF isolated from E. coli having remarkable immobilizing and spermicidal activity and no adverse effect on erythrocytes holds potential for the development of vaginal contraceptive agent against unwanted pregnancies.