Isolation of a spermatozoal immobilization factor from Staphylococcus aureus filtrates

Abstract

Staphylococcus aureus isolated from the cervix of an infertile woman was found to cause complete immobilization of human spermatozoa in vitro. Only the cell culture and cell-free supernatant showed immobilization activity, indicating that the sperm immobilization factor might be released extracellularly by the organism because no activity was observed with the washed cells. Heat treatment of the supernatant at 60 degrees C for 10 min waived its immobilizing activity, indicating that the active component may be a protein. The bioactive molecule from the supernatant was purified to homogeneity by ammonium sulfate precipitation, gel permeation chromatography, and ion exchange chromatography. Sperm immobilization factor (SIF) was found to be an approximately 20 kDa protein. SIF at a concentration of 10 microg/mL was required to cause 100% immobilization of human spermatozoa after 30 min of incubation at 37 degrees C, whereas a concentration of 150 microg/mL caused immediate immobilization, and a concentration of 200 microg/mL resulted in instant loss of viability of human spermatozoa, observed by eosin-nigrosin staining. Scanning electron microscopy showed that the treatment of human spermatozoa with SIF caused multiple defects in the head, midpiece, neck, and tail region of human spermatozoa.

Antifertility Effects of Sperm Impairing Factors Isolated from Bacteria in Male Mice

“…on seminal parameters do exist. In this regard, previously in our laboratory we have also isolated strains of S. aureus and E. coli that have been found to produce microbial factors with sperm immobilizing and sperm agglutinating properties in-vitro, respectively [12,13]. They were also found to possess excellent contraceptive efficacy in female BABL/c mice when administered intravaginally [10,17].…”

“…Animals were allowed to acclimatize to the new housing and experimental conditions for at least one week. Isolation and purification of sperm immobilization factor (SIF) from S. aureus SIF was extracted and purified from 72 h old cell culture of S. aureus by the method previously standardized in the laboratory [12]. Briefly, the cell culture of S. aureus grown in brain heart infusion (BHI) broth, under shake conditions (220 rpm) at 37°C for 72 h, was centrifuged at 10,000 rpm for 15 min at 4°C.…”

Intravaginal Delivery Approaches for Contraception: An Overview with Emphasis on Gels

“…On this account, microbial factors have flared up as the most reliable replacement to the chemical ingredients. In our laboratory, in pursuit of a newer contraceptive agent, a sperm immobilizing factor (SIF) has been extracted and purified from Staphylococcus aureus, isolated from a woman suffering from unexplained infertility (102). SIF having sperm immobilizing property, when administered in vivo, indicated complete blockage of conception in mouse model.…”

Isolation and Purification of Sperm Immobilizing/Agglutinating Factors from Bacteria and Their Corresponding Receptors from Human Spermatozoa

“…Fractions of 3 ml each were collected, and the absorbance of each fraction was read at 280 nm. Fractions (12)(13)(14)(15)(16)(17)(18) showing the immobilization activity were pooled and concentrated against PEG 6000 at 4°C (Figure 2a). These fractions were then applied onto DEAE cellulose column.…”

“…This purified fraction was then analyzed by SDS-PAGE against standard molecular weight markers (Figure 2c). The molecular weight of SIF was estimated to be ~20 kDa [18]. …”