QUANTITATIVE CONVERSION OF CELLS AND PROTOPLASTS OF
            <i>PROTEUS MIRABILIS</i>
            AND
            <i>ESCHERICHIA COLI</i>
            TO THE L-FORM

Landman, Otto E.; Altenbern, Robert A.; Ginoza, Herbert S.

doi:10.1128/jb.75.5.567-576.1958

Cited by 47 publications

(23 citation statements)

References 19 publications

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“…1958, ALTENBERN 1961, TAUBENECK 1962) it is not clear so far why under the same culture conditions one cell gives rise to a spheroplast type L-form and another cell will be transformed to a protoplast type L-form. Our results support the findings and opinions of other investigators (LANDMAN et al 1958, ALTENBERN 1961, TAUBENECK 1962) that these processes are influenced strongly by conditions of cult,ivation and by physical factors act.ing a t the surface of the agar medium. The' biochemical basis of the different modes of conversion, however, remains unknown.…”

Section: Discussionsupporting

confidence: 92%

Characterization of a stable spheroplast type L‐form of Proteus mirabilis D 52 as cell envelope mutant. I. Isolation, growth characteristics, biochemical activities, and sensitivity to bacteriophages

Gumpert

Taubeneck

1975

J of Basic Microbiology

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A stable spheroplast type L-form could be isolated by transferring 627 single colonies and 195 agar blocks with several colonies of unstable L-forms of Proteus mirabilis D 52 on agar media without supplements of penicillin. The L-form grows well on complex and synthetic agar media, however, it failed to grow in any of the liquid media which have been proved. With one except,ion (formation of acid from maltose) thel-form shows the same bioche mica1 activities like the parent rod-shaped bacterium. However, the insensitivity for variousphages and the failure of DAP in the envelopes demonstrate that there are profound alterations in the biosynthesis and structure of the murein and of the outer wall layers. The results of these investigations and a n ultrastructural analysis (GUMPERT and TAUBENECK 1975) show that the stable spheroplast type L-form LD 52B of Proteus inirabilis must be considered as a true cell envelope mutant.Among the different bacterial forms with altered cell envelopes the &able L-forms are those showing the most profound alterations. L-forms are protoplasts or spheroplasts which are able to grow and to multiply. Dependent on the presence or absence of cell wall structures and on their ability to revert to normal rod-shaped cells, they can be classified as unstable and stable protoplast type L-forms and unstable and stable spheroplast type L-forms, respectively (MARTIN 1964, TAUBENECK and GUM-PERT 1967). Many investigations were undertaken with Proteus mirabilis to explain especially the nature of the stable L-forms. I n a large number of experiments the production 0f.A and B type colonies as defined by DIENES and the isolation of stable protoplast type L-forms from A colonies have repeatedly been reported (DIENES and WEINBERGER 1951, KANDLER and KANDLER 1959, TAUBENECK 1962, TULASNE et al. 1960). However, it was only shortly mentioned by KANDLER and KANDLER (1956), SHARP and DIENES (1959), and TAUBENECK (1962) that also from B type colonies stable L-forms may be obtained. MARTIN (1964) described such an L-form in more detail. He found the cells to be surrounded by a cell wall structure and named this strains "stable spheroplast L-form".The present study describes experiments concerning isolation, conditions for induction, growth characteristics, biochemical activities, and sensitivity to phages of another stable spheroplast type L-form derived from Proteus mirabilis D 52. Together with an ultrastructural analysis (GUMPERT and TAUBENECK 1975) the results show that this stable spheroplast type L-form must be considered as a true envelope mutant. Whereas the main biochemical activities are the same like that of the rod-shaped parent bacteria, t,here are profound alterations in biosynthesis, structure, and function of the cell envelope.

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Section: Discussionsupporting

confidence: 92%

Characterization of a stable spheroplast type L‐form of Proteus mirabilis D 52 as cell envelope mutant. I. Isolation, growth characteristics, biochemical activities, and sensitivity to bacteriophages

Gumpert

Taubeneck

1975

J of Basic Microbiology

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“…It is possible that the solid substrate can exert some protective effect on septation. L forms of gram-positive and gram-negative strains, and spheroplasts which are unable to divide in liquid media, can form colonies on agar plates (17).…”

Section: Resultsmentioning

confidence: 99%

Control of cell septation by lateral wall extension in a pH-conditional morphology mutant of Klebsiella pneumoniae

Satta¹,

Canepari²,

Botta³

et al. 1980

J Bacteriol

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The pH-conditional morphology mutant of Klebsiella pneumoniae strain MirM7 grows as cocci at pH 7 and as rods at pH 5.8. The mutant has a high-level mecillinam resistance (50% lethal dose > 200 ,ug/ml) in both forms. When broth cultures of the rod-shaped mutant were grown with 0.7 ,ug of mecillinam per ml, cells assumed a round shape and continued to divide at a higher rate than the untreated control. A MirM7 rod-shaped revertant (MirA12), when treated with the same antibiotic concentration, changed to coccal shape and stopped dividing. The penicillin-binding proteins (PBPs) of strains MirA12 and MirM7 were analyzed. K. pneumoniae had six major PBPs quite similar to those of Escherichia coli. No differences were seen in the PBPs of MirM7 cocci and rods and MirA12 cells. In particular, PBP2 was found to be prepent and similar in MirM7 rods and cocci and MirA12 cells. We suggest that in gram-negative rods, a control mechanism exists which prevents further septation in the absence of lateral cell wall elongation. The unique behavior of MirM7 is due to the fact that the control mechanism is not active in this strain. This model allows us to explain the preservation of shape in bacterial rods under various conditions of growth and the mechanism of bacterial killing by mecillinam.

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“…Wide ranges of protocols for obtaining L-forms have been described (e.g. Dienes, 1948;Landman et al, 1958;King and Gooder, 1970;Joseleau-Petit et al, 2007). Unfortunately, obtaining a pure and stable L-form strain is usually a tedious process with a low success rate (Onoda et al, 1987;Allan, 1991;Dell'Era et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

The rod to L‐form transition of Bacillus subtilis is limited by a requirement for the protoplast to escape from the cell wall sacculus

Domı́nguez-Cuevas

Mercier

Leaver

et al. 2011

Molecular Microbiology

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SummaryL-forms are variants of common bacteria that can grow and proliferate without a cell wall. Little is known about their molecular cell biology but they undergo a remarkable mode of proliferation that is independent of the normally essential FtsZdependent division machinery. We have isolated a strain of Bacillus subtilis that can quickly and quantitatively convert from the walled to the L-form state. Analysis of the transition process identified an unexpected 'escape' step needed for L-form emergence from the rod. Mutations in two different genes, walR and sepF, contribute to the high frequency of escape: walR, a transcriptional regulator involved in cell wall homeostasis; and sepF, required for accurate and efficient cell division. Time-lapse imaging shows that the mutations act by facilitating the release of the L-form from its walled parent cell but that they act in different ways. The walR mutation renders the activity of the protein partially constitutive, inappropriately upregulating the activity of autolytic enzymes that weaken the cell wall. The sepF mutation probably works by perturbing the formation of a properly constructed division septum, generating a mechanical breach in the wall. The new strain provides a powerful experimental system for studying the genetics and cell biology of L-forms.

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QUANTITATIVE CONVERSION OF CELLS AND PROTOPLASTS OF PROTEUS MIRABILIS AND ESCHERICHIA COLI TO THE L-FORM

Cited by 47 publications

References 19 publications

Characterization of a stable spheroplast type L‐form of Proteus mirabilis D 52 as cell envelope mutant. I. Isolation, growth characteristics, biochemical activities, and sensitivity to bacteriophages

Characterization of a stable spheroplast type L‐form of Proteus mirabilis D 52 as cell envelope mutant. I. Isolation, growth characteristics, biochemical activities, and sensitivity to bacteriophages

Control of cell septation by lateral wall extension in a pH-conditional morphology mutant of Klebsiella pneumoniae

The rod to L‐form transition of Bacillus subtilis is limited by a requirement for the protoplast to escape from the cell wall sacculus

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