Growth of Bacterial L Forms and Bacterial Protoplasts

Weibull, Claes; Beckman, H.

doi:10.1128/jb.79.5.638-649.1960

Cited by 21 publications

(22 citation statements)

References 20 publications

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“…As can be seen, spherical elements of various sizes are present in this culture. This is in accord with earlier observations on the same L form (Weibull and Beckman, 1960;Weibull and Lundin, 1961;Weibull and Lundin, 1962a). In addition, threadlike structures appear.…”

Section: Relationship Between the Viable Count Of Pplosupporting

confidence: 93%

“…Some threadlike material is also present, but this material can hardly be confused with the filaments found in PPLO cultures. These threads are not clearly revealed in slide cultures prepared from liquid L form cultures (Weibull and Beckman, 1960;Weibull and Lundin, 1961;Weibull and Lundin, 1962a), even after fixation with formaldehyde. It could be added that the spherical elements found in L cultures differ very much in size and shape from the coccoid elements present in cultures of the saprophytic PPLO (M. laidlawii).…”

Section: Discussionmentioning

confidence: 91%

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Morphology of Pleuropneumonia-Like Organisms and Bacterial L Forms Grown in Liquid Media

Weibull¹,

Lundin²

1963

J Bacteriol

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AND BRIrr-MARIE LUNDIN. Morphology of pleuropneumonia-like organisms and bacterial L forms grown in liquid media. J. Bacteriol. 85:440-445. 1963.-Cells of Mycoplasma hominis, M. laidlawivi, and two tissue-culture strains of pleuropneumonia-like organisms (PPLO) moving freely in liquid medium were photographed with an electronic flash as the light source. The photomicrographs thus obtained demonstrated that, in young cultures of high viability, the cells of these organisms were mainly filamentous or, in the case of M. laidlawii, coccoid. In old cultures of the same organisms containing predominantly nonviable cells, granular and vesicular elements were found. By the use of the same photographic technique, liquid cultures of a stable Proteus L form were studied. Although no filaments of uniform thickness were found, there were spherical bodies and some threadlike material connected with the spheres. When samples of PPLO cultures containing filamentous forms were transferred to agar blocks, the filaments were converted to more or less spherical bodies. This conversion could be prevented by fixing the PPLO with formaldehyde. The morphology of Proteus L forms was not noticeably altered by fixation with this reagent.

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Section: Relationship Between the Viable Count Of Pplosupporting

confidence: 93%

Section: Discussionmentioning

confidence: 91%

Morphology of Pleuropneumonia-Like Organisms and Bacterial L Forms Grown in Liquid Media

Weibull¹,

Lundin²

1963

J Bacteriol

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“…This view is in agreement with the results reported by Carey and Baron in studies on S. typhi spheroplasts (5). The similarities existing between the normal Proteus cells and Proteus L forms with respect to the formation, chemistry, and toxicity of their endotoxins indicate that the conversion of normal bacteria into L forms leaves many important functions of the organisms unichanged, as has been pointed out elsewhere (15,41). However, indications of marked differences in the functions of the Proteus L forms and their parent bacteria were obtained during the present study.…”

Section: Discussionsupporting

confidence: 69%

Chemical, Biological, and Structural Properties of StableProteusL Forms and Their Parent Bacteria

et al. 1967

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Proteus L forms were disrupted by osmotic shock, and the sedimentable material present in the homogenate was further fragmented in a Sorvall pressure cell. The pressure cell was also used for disrupting normal Proteus cells. The homogenates obtained were fractionated by differential centrifugation. Purified endotoxins were isolated from the major fractions by phenol extraction. Material extracted with phenol from the membrane fraction of the L forms was about as toxic and pyrogenic on a weight basis as the typical enterobacterial endotoxins isolated from cell walls of normal bacteria. The yield of extract from L forms was about one-third of that from an equal weight of normal bacteria. No differences in the gross chemical composition of the phenol extracts from the L forms and the normal cells could be ascertained. A close serological relationship existed between extracts obtained from two L forms and their respective parent bacteria, but no such relationship was found in the case of the third L form studied and its parent bacterium. Diaminopimelic acid was not detected in the membranes of the L forms, but these membranes contained most of the succinic dehydrogenase of the organisms. Only small amounts of this enzyme were present in the wall fraction of normal bacteria. The data obtained suggest that precursors of the Proteus endotoxins are formed either in the soluble protoplasm of normal cells and L forms or at sites on the membrane from which they are readily liberated into the protoplasm, whereas the final steps of the synthesis of these toxins take place at the cytoplasmic membrane. In normal cells, much endotoxin is transported to and concentrated in the walls.

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“…However, balanced growth has not been unequivocally established for cultures of osmotically fragile cells. On the contrary, many earlier investigations of macromolecular biosynthesis in "protoplast" cultures demonstrated unbalanced (3,5,11) linear, rather than exponential, growth (6), or a lag prior to the onset of growth (5,9). A previous study from this laboratory indicated that "protoplasts" of Streptococcusfaecalik (ATCC 9790) could be obtained by treatment with lysozyme in the presence of 0.5 M sucrose (8).…”

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confidence: 84%

Balanced Macromolecular Biosynthesis in “Protoplasts” of Streptococcus faecalis

1971

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Osmotically fragile forms of Streptococcus faecalis 9790 were grown in 0.5 M sucroseor 0.5 M NH,Cl-stabilized medium. The "protoplast" cultures exhibit an average growth rate constant of 0.66 to 0.94 mass doublings/hr. In a variety of experi:ments, turbidity and the net content of protein, ribonucleic acid (RNA) and deoxyribonucleic acid increase at the same rate, indicating balanced macromolecular biosynthesis. A total of two to three mass doublings was obtained, with no evidence of cell division. After osmotic shock, "protoplast" cultures released 93 to 94% of their RNA content in a form not sedimentable at 12,800 x g for 15 min, in contrast to streptococci, which released 7% of their RNA content after the same treatment.

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Growth of Bacterial L Forms and Bacterial Protoplasts

Cited by 21 publications

References 20 publications

Morphology of Pleuropneumonia-Like Organisms and Bacterial L Forms Grown in Liquid Media

Morphology of Pleuropneumonia-Like Organisms and Bacterial L Forms Grown in Liquid Media

Chemical, Biological, and Structural Properties of StableProteusL Forms and Their Parent Bacteria

Balanced Macromolecular Biosynthesis in “Protoplasts” of Streptococcus faecalis

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