Morphological analysis of the division cycle of two Escherichia coli substrains during slow growth

Woldringh, Conrad L.; Jong, M A De; Berg, WB van den; Koppes, L H

doi:10.1128/jb.131.1.270-279.1977

Cited by 155 publications

(80 citation statements)

References 29 publications

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“…Cells grown in rich media have an average diameter of z1 µm, which is too thick for a reliable identification of most macromolecules. Slow growth in minimal medium results in cells with a diameter of z400 nm (Woldringh et al, 1977), improving tomogram quality significantly and thereby facilitating the recognition of macromolecular complexes. We recorded tomograms of E. coli cells grown in minimal media up to midexponential and stationary phases (Fig.…”

Section: Additional Proteins Associated With 100s Ribosomesmentioning

confidence: 99%

Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

Ortiz

Brandt

Matias

et al. 2010

Journal of Cell Biology

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Section: Additional Proteins Associated With 100s Ribosomesmentioning

confidence: 99%

Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

Ortiz

Brandt

Matias

et al. 2010

Journal of Cell Biology

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“…136, 1978 on July 15, 2020 by guest http://jb.asm.org/ Downloaded from of cell walls dried onto collodion films. We considered these results to be more readily interpretable than measurements of widths of dried whole cells (e.g., 51,53). The measured width of a cell depends on its cross-sectional shape, and this is not easily predictable for dried whole cells since it depends on properties of their contents.…”

Section: Selection Of Triton-resistant Variantsmentioning

confidence: 99%

Detergent-resistant variants of Bacillus subtilis with reduced cell diameter

Tilby¹

1978

J Bacteriol

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Variants of Bacillus subtilis resistant to the detergent Triton X-100 may exhibit: (i) normal cell morphology, (ii) reduced cell diameter, or (iii) helical cell shape. One variant of type ii was studied in some detail. Triton resistance, cell diameter reduction, and poor sporulation all may have resulted from a single mutation. High concentrations of Triton caused rapid lysis of wild-type cells. B. subtilis adapted to low Triton concentrations such that, upon subsequent exposure to higher concentrations, growth continued, although it bacame inhibited at very high concentrations. The variant studied retained its sensitivity to Triton-induced lysis but, after adaptation, grew at very high Triton levels. In this strain, cell diameter and cross-sectional area were reduced to about 73 and 50%, respectively, of those of wild type, yet the cells grew at normal rates, and DNA/protein/RNA ratios were largely unaltered. Peptidoglycan content per unit of cell surface area was higher in the variant than in the wild type under at least certain growth conditions.

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“…Measurement of cell length. Analysis of cell length was obtained using electron microscopy of cells prepared by agar filtration according to the method of Woldringh et al (15). For each size distribution at least 300 cells were measured.…”

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Synchronization of cell division in microorganisms by percoll gradients

Dwek¹,

Kobrin²,

Grossman³

et al. 1980

J Bacteriol

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We describe a method for obtaining synchronously dividing cells of bacteria (Escherichia coli B and K-12 and Bacillus subtilis 168) and fission yeasts (Schizosaccharomycespombe) by the use of Percoll density gradients.Several synchronization techniques have been developed for the study of sequential changes during the division cycle of bacteria. The methods consist of induction of synchrony by specific environmental shifts (such as temperature [3] or nutrition [11]) or by separation of newly divided cells by filtration (4) or by centrifugation (6). One of the best methods for selection of newly divided cells is the membrane elution technique developed by Helmstetter (2). The method consists of selectively eluting newly divided cells from a randomly growing culture adsorbed to an inverted Millipore membrane filter. The advantage of this technique is that the physiological perturbations are minimal. The major disadvantages are the low yield of cells, which renders conventional biochemical methods inapplicable, and the fact that satisfactory synchrony is obtained only with strains B/r (2) and B (10) of Escherchia coli. Since many cell division mutants were isolated in E. coli K-12, which is not easily synchronized by the membrane elution technique (13), we looked for another method for obtaining newly divided cells which will be more general and also applicable for E. coli K-12. Our results with sucrose gradients (1, 6) were unsatisfactory due to an inhibitory effect on the cells and to poor synchrony, and Ludox gradients, which have also been used (9), are toxic and very viscous.We describe here separation of newly divided cells by the use of Percoll gradients. Percoll has been previously used in mammalian tissue cultures for separation of cells and cell organelles (7) and for enrichment of viable cells. Percoll is colloidal silica which is coated with polyvinylpyrrolidone to protect the cells from toxic effects. One of the major advantages of Percoll is that there is no free polymer in the solution, and therefore the viscosity is relatively low, even at high densities, and the osmotic properties are good. It was found by Pertoft et al. (8) that mammalian cells are less inhibited by Percoll than by other density gradients such as Ficoll, metdizamide, and sodium metrizoate.We studied the effect of Percoll on several microorganisms and its possible use for obtaining synchronously dividing cultures. The results presented in this communication indicate that synchronized cultures can be obtained in bacteria (E. coli B and K-12 and Bacillus subtilis 168) and in yeasts (Schizosaccharomyces pombe) by selecting newly divided cells from an exponentially growing culture.MATERIALS AND METHODS Strains and growth conditions. E. coli K-12 DG-76 (F-thyA47 leu-6 dra-3 str-153; kindly supplied by B. Bachmann) and E. coli B (thyA ilvA; obtained in our laboratory by mutagenesis of E. coli B) were grown in a minimal salts medium (2) containing 0.2% glucose and supplemented, when required, with 20 ,ug of thymine, 50 ,ug of the required ...

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Morphological analysis of the division cycle of two Escherichia coli substrains during slow growth

Cited by 155 publications

References 29 publications

Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

Detergent-resistant variants of Bacillus subtilis with reduced cell diameter

Synchronization of cell division in microorganisms by percoll gradients

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