ELECTRON MICROSCOPY OF PLASMOLYSIS IN
            <i>ESCHERICHIA COLI</i>

Cota-Robles, E. H.

doi:10.1128/jb.85.3.499-503.1963

Cited by 53 publications

(25 citation statements)

References 6 publications

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“…Accumulations of electron-dense material were seen frequently in the bays of the plasmolyzed cells. The appearance of these cells was in general the same as that of Escherichia coli cells plasmolyzed by suspension in concentrated solutions of sugars or salts (1,4,14) except that the marine pseudomonad seemed to have a more contracted irregular outline. A freeze-etched preparation of the plasmolyzed cells also showed evidence of bays and indentations ( Fig.…”

Section: Effect Of Washing Solution On Cell Morphologymentioning

confidence: 71%

K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

1970

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When cells of a marine pseudomonad were washed with a solution consisting of 0.3 M NaCl, 0.05 M MgSO4, and 0.01 M KCl (complete salts), they maintained their normal morphology. When washed with a solution of 0.05 M MgSO4, they became plasmolyzed as indicated by both phase and electron microscopy. Suspensions of cells washed with 0.05 M MgSO4 showed an increase in optical density (OD) when 0.3 M NaCl was added, and this was followed by a decrease in OD upon the further addition of 0.01 M KCl. Salts of other monovalent cations were not effective in replacing K+ in producing the OD decrease. Phase-contrast microscopy revealed that the increase in OD was accompanied by a decrease in cell size, and the decrease in OD, by an increase in the cell size. Both phase and electron microscopy showed that the K+-dependent decrease in OD was accompanied by deplasmolysis of the cells. Na+ was required in the suspending medium in addition to K+ to obtain deplasmolysis. The intracellular K+ concentration in cells which had been washed with complete salts and which had retained their normal morphology was found to be 0.290 M. In cells plasmolyzed by washing with 0.05 M MgSO4, the intracellular K+ concentration was 0.004 M. Deplasmolyzed cells contained 0.330 M K+. The membrane profile of plasmolyzed cells was retained when protoplasts were formed. The protoplasts became spherical if incubated in a solution permitting the deplasmolysis of the parent cells. The evidence obtained indicates that plasmolysis and deplasmolysis under the conditions described was due to the loss and gain, respectively, of K+ by the cells. The effect of Na+ could be ascribed to its capacity to control the porosity of the cytoplasmic membrane of this organism. 850

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Section: Effect Of Washing Solution On Cell Morphologymentioning

confidence: 71%

K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

1970

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“…In a further analysis of the consequences of pnd gene expression we have found a drastic effect on the response of cells to hypertonic medium. Ordinarily, E. coli cells are plasmolyzed in such a medium: internal water is lost, the cytoplasm shrinks, and the cytoplasmic membrane is caused to retract from the cell wall (3,8,32). But when we exposed the cells to a hypertonic sucrose solution after the addition of rifampicin to induce the pnd protein, plasmolysis was largely abolished.…”

Section: Induction Of Plasmolysis In Cells Carrying the Pnd Genementioning

confidence: 99%

Nucleotide Sequence of the pnd Gene in Plasmid R483 and Role of the pnd Gene Product in Plasmolysis

Ono

Akimoto

Ohnishi

1987

Microbiology and Immunology

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The pnd gene of R plasmid R483, like the srnB gene of the F plasmid, increases the degradation of stable RNA in Escherichia coli. The nucleotide sequence of the pnd locus was determined and compared with that of the srnB locus. The genes have open reading frames that are 54% homologous, and both have an upstream inverted repeat sequence.The pnd gene expression seems to decrease the osmotic barrier of the cytoplasmic membrane, since no plasmolytic vacuoles were formed in the cells carrying the gene when the cells were exposed to hypertonic sucrose solution.This result suggests that RNase I in the periplasm passes through the altered membrane to degrade stable RNA in the cytoplasm.

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“…1-4). This configuration has generally been attributed to shrinkage of the protoplast by hypertonic solutions (10). The ends of the protoplast generally appeared blunt or indented, and the resulting polar spaces were continuous with the narrower lateral periplasmic space ( Fig.…”

mentioning

confidence: 94%

Cytochemical Localization of Certain Phosphatases in Escherichia coli

et al. 1970

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Cytochemical studies of Escherichia coli at the light and electron microscopic levels have revealed alkaline phosphatase, hexose monophosphatase, and cyclic phosphodiesterase reaction products in the periplasmic space and at the cell surface. In preparations for both light and electron microscopy, reaction product filled polar caplike enlargements of the periplasmic space, such as those described in plasmolyzed cells, indicating significant terminal concentrations of these enzymes; dense substance was often seen within these polar caps in morphological specimens. Staining of the bacterial surface was commonly encountered, but could represent artifactual accumulation of precipitate along the cell wall. Alkaline phosphatase was demonstrated with several substrates (ethanolamine phosphate, glycerophosphate, p -nitrophenylphosphate, and glucose-6-phosphate) over a wide p H range in a bacterial strain (C-90) known to be constitutive for this enzyme, whereas strains deficient in this enzyme (U-7, repressed K-37), showed no activity with these substrates. Hexose monophosphatase and cyclic phosphodiesterase activities were characterized by reaction-product deposition with specific substrates at acid or neutral, but not at alkaline, p H in strains of E. coli lacking alkaline phosphatase (U-7 and repressed K-37). Fixation in Formalin or the use of calcium as a capture reagent seemed to interfere with periplasmic staining in cells prepared for electron microscopy. Formalin fixation had little effect on biochemical assays of the phosphatase activity of intact cells in suspension, but partially reduced the activity evident in sonically treated extracts or in suspensions of dispersed cryostat sections. Glutaraldehyde treatment impaired enzyme activity more drastically.

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ELECTRON MICROSCOPY OF PLASMOLYSIS IN ESCHERICHIA COLI

Cited by 53 publications

References 6 publications

K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

Nucleotide Sequence of the pnd Gene in Plasmid R483 and Role of the pnd Gene Product in Plasmolysis

Cytochemical Localization of Certain Phosphatases in Escherichia coli

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ELECTRON MICROSCOPY OF PLASMOLYSIS IN ESCHERICHIA COLI

Cited by 53 publications

References 6 publications

K + -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

K + -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

Nucleotide Sequence of the pnd Gene in Plasmid R483 and Role of the pnd Gene Product in Plasmolysis

Cytochemical Localization of Certain Phosphatases in Escherichia coli

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K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution

K ⁺ -Dependent Deplasmolysis of a Marine Pseudomonad Plasmolyzed in a Hypotonic Solution