Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology


Throughout the past decade, there has been remarkable increase of interest in studies of bacterial L-forms and mycoplasmas. These studies have enriched our understanding of the functions of various components of bacterial cells. Questions of primary interest deal with the probable role of L-forms in recurrent infections and in disease. The purpose of this investigation was to determine the effect of Listeria L-forms on impregnation of mammals. Infection appeared to disturb pregnancy by disruption of implantation of the embryo or by abortion or reabsorption of the embryo. Infection appeared to disturb conception by prevention of implantation of the embryo or by prevention of penetration of the egg by sperm. Results of the second and third studies implied that abortion would be the most probable mechanism. Data from this investigation indicate that the infection may be enhanced by the indiscriminate and/or low-level administration of antibiotics to animals. Low-level administration of antibiotics in feed could result in a potential danger to brood animals. Induction of the L-form in vivo from the potential or actual pathogenic bacterium could be economically harmful during and after impregnation. Further, the L-form within the system could revert to the pathogenic bacterial form. The mouse placenta is the most complex placenta of any animal. Therefore, the effects of Listeria L-forms on porcine, equine, bovine, ovine or other placentae may be more pronounced than these effects found in mice.

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South Dakota State University Theses



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South Dakota State University