Mechanism of sperm immobilization by Escherichia coli.
OBJECTIVE
To explore the influence of Escherichia coli on the motility of human spermatozoa and its possible mechanism.


METHODS
Highly motile preparations of spermatozoa from normozoospermic patients were coincubated with Escherichia coli for 4 hours. At 1, 2 and 4 hours of incubation, sperm motility was determined. The factor responsible for sperm immobilization without agglutination was isolated and purified from filtrates.


RESULTS
This report confirms the immobilization of spermatozoa by E. coli and demonstrates sperm immobilization factor (SIF) excreted by E. coli. Further this factor was purified by ammonium sulfate precipitation, gel permeation chromatography, and ion-exchange chromatography. Purified SIF (56 kDa) caused instant immobilization without agglutination of human spermatozoa at 800 microg/mL and death at 2.1 mg/mL. Spermatozoa incubated with SIF revealed multiple and profound alterations involving all superficial structures of spermatozoa as observed by scanning electron microscopy.


CONCLUSIONS
In conclusion, these results have shown immobilization of spermatozoa by E. coli and demonstrate a factor (SIF) produced and secreted by E. coli which causes variable structural damage as probable morphological correlates of immobilization.
Prabha
Vijay
V
Department of Microbiology, Panjab University, Chandigarh-160014, India. satishvijay11@yahoo.com
Sandhu
Ravneet
R
Kaur
Siftjit
S
Kaur
Kiranjeet
K
Sarwal
Abha
A
Mavuduru
Ravimohan S
RS
Singh
Shravan Kumar
SK