(Symposium on Bmterial Spores: Paper I). Cytology of Spore Formation and Germination

Walker, P. D.

doi:10.1111/j.1365-2672.1970.tb05229.x

Cited by 36 publications

(1 citation statement)

References 86 publications

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“…Transmission electronic microscopy (TEM) has traditionally been the technique used to study the formation and architecture of Firmicutes spores 3 . Pioneer TEM studies revealed that the general architecture of spores and the sporulation steps are conserved among Firmicutes species 4 . Firstly, the cell entering sporulation divides asymmetrically into a small cell, the forespore (or prespore) and a larger mother cell, both defining a sporangium (Fig.…”

Section: Introductionmentioning

confidence: 99%

A new fluorescence-based approach for direct visualization of coat formation during sporulation in Bacillus cereus

Lablaine,

Chamot,

Serrano

et al. 2023

Sci Rep

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The human pathogenic bacteria Bacillus cereus, Bacillus anthracis and the entomopathogenic Bacillus thuringiensis form spores encased in a protein coat surrounded by a balloon-like exosporium. These structures mediate spore interactions with its environment, including the host immune system, control the transit of molecules that trigger germination and thus are essential for the spore life cycle. Formation of the coat and exosporium has been traditionally visualized by transmission electronic microscopy on fixed cells. Recently, we showed that assembly of the exosporium can be directly observed in live B. cereus cells by super resolution-structured illumination microscopy (SR-SIM) using the membrane MitoTrackerGreen (MTG) dye. Here, we demonstrate that the different steps of coat formation can also be visualized by SR-SIM using MTG and SNAP-cell TMR-star dyes during B. cereus sporulation. We used these markers to characterize a subpopulation of engulfment-defective B. cereus cells that develops at a suboptimal sporulation temperature. Importantly, we predicted and confirmed that synthesis and accumulation of coat material, as well as synthesis of the σK-dependent protein BxpB, occur in cells arrested during engulfment. These results suggest that, unlike the well-studied model organism Bacillus subtilis, the activity of σK is not strictly linked to the state of forespore development in B. cereus.

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Section: Introductionmentioning

confidence: 99%

A new fluorescence-based approach for direct visualization of coat formation during sporulation in Bacillus cereus

Lablaine,

Chamot,

Serrano

et al. 2023

Sci Rep

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Zum Mechanismus des Membranwachstums. Untersuchungen an Bakterien mit der Gefrierätzung

Meyer

Richter

1971

J of Basic Microbiology

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With a strain of bacteria isolated from distilled water it is possible to demonstrate splitting of the cytoplasmic membrane during freeze-fracturing. The fracture faces of the membrane are covered with particles, but in these bacteria frequently smooth areas appear. A second feature is a network-?ike pattern in distribution of particles caused by many small arid round areas free of particles. Smooth areas and the network-like pattern are occurring especiallyinsampIes of growing cultures and of damaged cells, whereas in samples of non-growing cultures both are very seldom. I n earlier investigations the dislocation of particles could be attributed to alterations in the structural proteins of the membrane. Therefore, the same is assumed for the occurrence of areas without particles on physiological conditions. The network-like pattern corresponds probably to one stage in the mechanism of growth of the membrane that of widening of the"mes1ies" of the network-like arrangement of structural proteins by loosening in several spots.

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Autolysis of Thermoactinomyces vulgaris spores lacking carbon dioxide during germination

Kretschmer

Jacob

1983

J of Basic Microbiology

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Ultrathin sections of early germinating endospores of !Phermoactinomyces vulgaris were studied by electron microscope. Only spores aerated with a n air-COB mixture (5% C02) grow out, while spores aerated with air (0.03% CO,) lyse by the 25th min of inoculation. The lysis is due to progressive, unlimited degradation of the spore integuments and a lack of cell wall formation around the spore protoplast.The requirement of CO, for outgrowth could not be replaced by oxaloacetate. CO, seems to be needed to energize the dormant cytoplasmic membrane of the spore t o render i t capable of initiating active transport processes and of synthesizing the germ cell wall.Studying the germination behaviour of Thermoactinomyces vulgaris spores we found that aeration inhibited outgrowth. The initiation of germination, i.e. swelling and fall of optical density was not affected. The inhibitory effect of aeration was compensated by mixing 2-5% CO, to the flowing air during the first 15 min, or by using very dense spore suspensions. Measuring the respiratory activity of germinating spores we found that CO, was produced immediately after swelling. At first CO, was produced with low, but then with steadily increasing rate. This CO, accumulated in the unaerated cultures, but was eliminated in the aerated ones (KRETSCHMER and JACOB 1978).Since inhibition became irreversible already by the gth min after swelling, aeration is thought to damage the spores severely. I n order to elucidate the kind of damage and to discover the function of CO, in supporting outgrowth, the fine structure of spores germinated during aeration (0.03% CO,) was conipared to that of spores aerated with an air-CO, mixture (5% 0,).Spores of Thermoactinomyces vulgaris strain 4 were used. The procedures for harvesting spores from agar medium, for activation, storage and germination were described by STROHBACH and KRETSCHMER (1977). The spores were inoculated into liquid medium (salt-sucrose-casamino acids medium, 50 "C) a t a density of about 1.5. l o 7 . ml-I. One culture was aerated with prewarmed air (aerated spores) and the other with an air-5% CO, mixture (C0,-spores) by bubbling each with 20 1 h-1 gas per 7 0 ml medium. 0.02 M phosphate buffer was added to both cultures to maintain the p H a t about 7.0. After 25 min the spores were fixed with OsO, and embedded according t o KELLENBERGER et aZ. (1958). Ultrathin sections of the spores were studied with a n electronmicroscope Type SEM 3-2 (VEB Werk fur Fernsehelektronik, Berlin-Oberschoneweide) operating at 80 kV.Concerning fine structure as well as sporulation and germination behaviour the endospores of T . vulgaris are similar to those of bacilli (CROSS and ATTWELL 1975, KALAKOUTSKII and AGRE 1976, ENSIGN 1978. The spore integuments consist of an electron dense outer coat, a niultilayered inner coat and the inner pale cortex (Fig. 1). As is known from spores of bacilli and T. sacchari (FITZ-JAMES and YOUNG 1969, 28 S. KRETSCHMER and H.-E. JACOB c : W encloses the spore protoplast.d, e: The spore protoplast surroun...

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(Symposium on Bmterial Spores: Paper I). Cytology of Spore Formation and Germination

Cited by 36 publications

References 86 publications

A new fluorescence-based approach for direct visualization of coat formation during sporulation in Bacillus cereus

A new fluorescence-based approach for direct visualization of coat formation during sporulation in Bacillus cereus

Zum Mechanismus des Membranwachstums. Untersuchungen an Bakterien mit der Gefrierätzung

Autolysis of Thermoactinomyces vulgaris spores lacking carbon dioxide during germination

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