Participation of the Cytoplasmic Membrane in the Growth and Spore Formation of Bacilli

Abstract

A polyester embedding technique was used to study the early stages of spore formation in members of the genus Bacillus in order to investigate further the origin and nature of the initial spore septum and the resulting forespore envelope. Whereas previously, with a methacrylate procedure, this layer had appeared to be continuous with the cell wall, this study reveals it as a double layer of cytoplasmic membrane. Perisporal, membranous organelles connected both to the developing forspore envelope and to the cytoplasmic membrane were encountered in the four species studied. Similar organelles were prominent during growth at the sites of transverse septa formation. These were connected to, or continuous with, the cytoplasmic membrane and often adherent to the chromatin bodies of the dividing bacilli.

The Localization of Cytochromes and Carotenoids in Isolated Bacterial Membranes and Envelopes

“…It can be concluded that other investigators working with mcmbraue preparations described as "protoplast membranes" are also dealing with the whole plasma-mesosome membrane system. At present there is no way of distinguishing between plasma aud mesosome membraucs aud as suggested by Fitz-James (1960) there may be uo real difference, a conclusion supported by recent evidence from ultra-centrifuge data obtained in our laboratory.…”

“…With the improved methods of fixing and sectioning bacteria for the electron microscope it became apparent that bacterial cells possessed a well-developed intracellular membrane system (Ryter aud Kellenberger, 1958) originating from the invagiuation of the plasma membrane to give the "mesosome" .structiue (Fitz-James, 1960). Salton and Chajmiau (1962) showed that the membrane fractions isolated from Microeoeeus lysodeikticus contained both plasma and mososome membranes.…”

Fine Structure of Intracytoplasmic Membrane System in Listeria Monocytogenes

“…Using their technique, several investigators (3)(4)(5)(6)(7)(8) have observed in sections of some bacteria and streptomycetes that the cytoplasm contains complex and membraneous organelles, which have been designated as the intracytoplasmic membrane system by GLAUERT and HoPwooD (4). Our recent observation on the membrane system in Corynebacterium diphtheriae (9) has prompted a similar study on the intracellular structure of Listeria monocytogenes, an organism which also belongs to the family Corynebacteriaceae.…”

Ultrastructure of the Obligately Anaerobic Bacteria Clostridium Kluyveri and Cl. Acetobutylicum

“…15). On this basis they can be termed mesosomes as defined by Fitz-James (1960). In sections the plasma membrane cannot be traced completely round a mesosomal profile and therefore in both plasmolysed and normal cells the membrane is either discontinuous or has variable staining characteristics.…”