Electron Microscope Observations on the Behavior of the Bacterial Cytoplasmic Membrane During Cellular Division

Chapman, George B.

doi:10.1083/jcb.6.2.221

Cited by 44 publications

(26 citation statements)

References 19 publications

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“…The upper and lower parts of layer 3join at the inner edge of the cross-wall. This is a second point supporting the interpretation that layer 3 is the plasma membrane of the cell (Chapman, 1959).…”

Section: Resultssupporting

confidence: 67%

THE PLASMA MEMBRANE OF STAPHYLOCOCCUS AUREUS

Suganuma

1961

The Journal of Cell Biology

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Section: Resultssupporting

confidence: 67%

THE PLASMA MEMBRANE OF STAPHYLOCOCCUS AUREUS

Suganuma

1961

The Journal of Cell Biology

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“…In pneumococcus as in a number of other bacteria (19,20), the centripetal growth of the septal membrane precedes the formation of the crosswall, and in sections of this organism one finds the growing tip of the septal membrane either continuous with chondrioids ( Figs. 3 and 4) or with S membranes (Figs.…”

Section: Intracytoplasmie Membranes and Septal Growthmentioning

confidence: 96%

THE FINE STRUCTURE OF DIPLOCOCCUS PNEUMONIAE

Tomasz

Jamieson

Ottolenghi

1964

The Journal of Cell Biology

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A B S T R A C TThe fine structure of an unencapsulated strain of Diplococcus pneumoniae is described. A striking feature of thcsc bacteria is an intracytoplasmic m e m b r a n e system which appears to be an extension of septa of dividing bactcria. The possible function of these structures and their relationship to the plasma m e m b r a n e and other types of intracytoplasmic membranes found in pncumococcus is discussed. I N T R O D U C T I O NO u r main interest in the fine structure of Diplococcus pneumoniae stems from the fact that these bacteria readily undergo genetic transformation. Prior to undertaking electron microscope studies on this process, the fine structure of pneumococcal cells in thin sections was examined. During the preliminary stage of these studies on a transformable strain, we observed some unique membranous structures which, to the best of our knowledge, have not previously been described in bacteria. M A T E R I A L S A N D M E T H O D SUnencapsulated strains of Diplocoecus pneumoniae R6, R1, and some nutritional mutants derived from R6 were used in these studies. These strains were derived from Diplovoceus pneumoniae R36A (1) which has been used as a laboratory strain for over 20 years. Forty-ml batches of bacteria were grown in a modified Adams-Roe medium (2) (medium A) or in a semisynthetic medium (3) (medium B) at 37°C in 25 x 150 mm tubes, without aeration. Small inocula (105 cells/ml) of cells from the exponential phase of growth were used and the cultures were harvested in the late exponential phase. In these media, stationary phase cultures undergo spontaneous autolysis, the first recognizable stage of which is a quantitative conversion of the cocci to fragile spherical bodies of fairly uniform size which are deficient in their cell walls. Throughout this paper, such preparations will be referred to as "spheroplasts."The bacteria were fixed and stained according to the method of Ryter and Kellenberger (4), embedded in cross-linked methacrylate, and sectioned with a Porter-Blum mlcrotome using a diamond knife. The sections were stained with lead according to the method of Karnovsky (5) (method B) and were examined in the RCA electron microscopes models 2B, 3F, or in the Siemens Elmiskop I. R E S U L T SThe nuclear region of pneumococcus resembles that of other bacteria prepared by the method of Ryter and Kellenberger (4). It is located centrally in the cell, is devoid of a nuclear membrane, and has a density lower than that of the surrounding cytoplasm (Fig. 1). The nuclear region is filled with more or less tightly packed uniform fibrils 25 to 30 A wide (Fig. 2).Differences in the internal structure of the nuclear region could be observed from one experiment to another or even in adjacent cells within the same section, in spite of the fact that the preparative procedure was the same throughout.These variations were essentially of three types: variation in the degree of interpenetration of the nuclear region and the cytoplasm which ranged 453 on

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“…Entspreehende elek~ronenmikroskopische Befunde deuten zwar darauf bin, dab die cyboplasmatisehe Membran w~hrend der Teilung zeitlieh vor der Zellwand das Cytoplasma der belden Toehterzellen voneinander trennt, doch wird dieser Vorgang als i~eubildung eines Septums angesehen [11,12]. Entspreehende elek~ronenmikroskopische Befunde deuten zwar darauf bin, dab die cyboplasmatisehe Membran w~hrend der Teilung zeitlieh vor der Zellwand das Cytoplasma der belden Toehterzellen voneinander trennt, doch wird dieser Vorgang als i~eubildung eines Septums angesehen [11,12].…”

Section: Morphologie Des Vermehrungsvorgangesunclassified

Morphology and multiplication ofMycoplasma hominis in phase contrast

Bredt

1970

Z. med. Mikrobiol. u. Immunol.

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Morphology and Multiplication o] Mycoplasma hominis in Phase Contrast~ummary. Ten strains of M. hominis growing in liquid medium in coverslip chambers were observed by phase contrast microscope. The myeoplasmas grew on the glass as eoccoidal ceils, diploforms, filaments of different length, as ring-or discforms respectively, as rosettes, and as combinations of these basic structures. The coceoidal forms had diameters of 0.3--0.8 tzm, the filaments were about 0.3--0.4 t~m thick and up to more than 40 ~m long. Branching has been seen very seldom. No morphological differences were observed between the structures adhering to the glass and those moving free in tile medium. Variations of growth conditions caused only slight changes of morphology. The laboratory strain PG 21 formed after numerous passages on arteficial media mainly large coccoidal cells, whereas freshly isolated strains formed more rings and filaments. Single growing cells were observed continuously up to 10hrs and more in a slightly viscous medium (2.5~ gelatine added). The mycoplasmas multiplied by binary fission (1 h 40 rain to 3 hm), fragmentation of filaments and rings, and some budding-like processes. The separation of daughter cells seemed to be caused by some kind of constriction of the cell membrane or the cell plasma. During the process of replication reversible changes of the cell form were often observed, especially on small rings and short filaments. These changes too seemed to be caused by active constrictions of the cell membrane. The beginning fragmentation of filaments was sometimes reverting. There was no evidence for special growth cycles or submieroscopical elementary bodies. Zusammen/assung. Zehn S~mme yon M. hominis warden in fliissigem Medium in Deckglaskammeru phasenkontrastmikroskopisch beohachtet. StSrende Einwirkungen ~u0erer Kr~fte konnten durch die geschlossenen Kammeru weitgehend ansgeschaltet werden. Die Myeoplasmen wuchsen am Deckglas in Form yon kokkoiden Zellen, Diploformen, Filamenten unterschiedlicher L~nge, l~ing-bzw. Scheibenformen und Itosetten sowie in Kombination dieser Grundstruktnren. Ycrzweigungen waren selten. Die an Glas haftenden Strukturen unterschieden sich nlcht * Die Untersuchungen wurden yon der Deutschen Forschungsgemeinschaft unterstiltzt. --Frl. G. Maisch danke ich fiir technische Assistenz.

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Electron Microscope Observations on the Behavior of the Bacterial Cytoplasmic Membrane During Cellular Division

Cited by 44 publications

References 19 publications

THE PLASMA MEMBRANE OF STAPHYLOCOCCUS AUREUS

THE PLASMA MEMBRANE OF STAPHYLOCOCCUS AUREUS

THE FINE STRUCTURE OF DIPLOCOCCUS PNEUMONIAE

Morphology and multiplication ofMycoplasma hominis in phase contrast

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