Fine Structure of Listeria monocytogenes
- M R Edwards, Stevens
- J. Bact
Rober tson has advanced the concept tha t all l ipoprotein membranes in and a round cells have the characterist ic triple-layered 'uni t membrane s t ructure" (8 10). O the r authors have reported occasional exceptions. Thus Lillibridge (6) described a single-layered m e m b r a n e in pepsiniferous cells in h u m a n stomach, and Kar re r (4) has ment ioned certain vesicles in lung phagocytes as being surrounded by thin, single-layered membranes differing from those conforming to Robertson 's uni t m e m b r a n e structure. In two previous studies (11, 12), the plasma m e m b r a n e of Staphylococcus aureus was seen as a single-layered structure about 50 A thick, resembling the exceptions to the uni t m e m b r a n e structure ment ioned above. In the course of subsequent efforts, it has been possible to demonstrate a typical triple-layered uni t membrane in the case of S. aureus, using a special preparat ive technique. This demonst ra t ion suggests tha t the plasma m e m b r a n e of S. aureus may possess a true uni t membrane structure, par t of which may be masked when observed after the usual prepara t ive techniques for electron microscopy.