Bacterial Protoplasts Induced by Penicillin

Lederberg, Joshua

doi:10.1073/pnas.42.9.574

Cited by 302 publications

(142 citation statements)

References 8 publications

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“…was used for making the protoplasts. From Gram-negative bacteria only penicillin-induced ' protoplasts ' were studied, prepared according to the technique of Lederberg (1956).. Bu,ered saline solution. 0.9 g. NaC1/100 ml.…”

Section: Methodsmentioning

confidence: 99%

“…Megacin concentrates of high activity now offer an opportunity to investigate the specificity of megacin action on protoplast preparations made from different organisms ( Table 2). Some of our ' protoplast ' preparations were made by the penicillin technique (Lederberg, 1956). While we designate all our preparations as 'protoplast', that is only for the sake of simplicity, since we accept the distinction between penicillin-and lysozymeformed 'protoplasts' (Brenner et al 1958).…”

Section: The Speci$city Of Megacin Actionmentioning

confidence: 99%

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Mode of Action of Megacin

Ivánovics

Alfoldi

Nagy

1959

Journal of General Microbiology

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SUMMARY : Megacin however highly bactericidal for sensitive organisms was not adsorbed by them. Its bactericidal action was markedly dependent on temperature. The viability of organisms exposed to megacin at 0' was not affected. When megacin was added to exponentially growing Bacillus megatm'um there was cessation of growth followed by a gradual decrease in turbidity of the culture. The decrease in turbidity was, however, not associated with a total lysis of individual organisms; rather it. was the consequence of the escape of the dense intracellular material from the organisms. Intracellular components, i.e. substances which absorbed in the ultraviolet region escaped from the bacteria into the medium while cell wall remained essentially intact. When B. megaterium suspended in a medium containing lactose was exposed to megacin, p-galactosidase appeared on the surface of bacteria.Protoplast preparations made from Bacillus megaterium and Mimococcus aurantiacus (both sensitive to megacin) were converted into ghost-like structures on the addition of megacin. On the other hand, protoplasts made from insensitive species resisted megacin. Observations indicate that megacin causes a radical change in the osmotic barrier of sensitive organisms by attacking the cytoplasmic membrane. Data available suggest that megacin is either an enzyme which breaks down the osmotic barrier of sensitive cells, or is a substance capable of activating the intrinsic enzymes of cells which lead to an autolysis of cytoplasm.

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Section: Methodsmentioning

confidence: 99%

Section: The Speci$city Of Megacin Actionmentioning

confidence: 99%

Mode of Action of Megacin

Ivánovics

Alfoldi

Nagy

1959

Journal of General Microbiology

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“…Spheroplasts are Gram-negative bacteria that have lost their peptidoglycan layer but not their outer membrane, whereas protoplasts lack both a peptidoglycan layer and an outer membrane, either because they were formed from Gram-positive bacteria, or because their outer membrane has been stripped away [70]. Various agents convert bacteria into these altered forms, with the peptidoglycan synthesis inhibitor penicillin G [71] and the peptidoglycan digesting enzyme lysozyme [72] among the first discovered. The significance of these early observations, incidentally, was not lost on researchers at Merck, Fujisawa or Sankyo, all three companies developing screens for cellwall synthesis inhibiting antibiotics based on spheroplast formation [73].…”

Section: Spheroplast and Protoplast Formationmentioning

confidence: 99%

Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action

Cushnie

O’Driscoll

Lamb

2016

Cell. Mol. Life Sci.

155

124

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“…In order to achieve suffi cient killing of the parent cells, it is essential to incubate the cells in penicillin for 6-24 h. The primary action of ampicillin/penicillin on sensitive bacteria is to induce protoplast formation by interfering with cell wall synthesis 60 . These protoplasts then burst osmotically, releasing nutrients into the minimal medium.…”

Section: Isolation and Identifi Cation Of Auxotrophic Mutantsmentioning

confidence: 99%

“…Growth in the presence of ampicillin or penicillin in the complete or enriched medium ordinarily causes lysis but in a hypertonic medium, the cells are instead converted to protoplasts 57,60,62 . In the method of Gorini and Kaufman 61 , 0.6 M sucrose and 0.01 M Mg SO 4 were added to the penicillin selection medium in order to prevent lysis and thereby to decrease crossfeeding.…”

Section: Isolation and Identifi Cation Of Auxotrophic Mutantsmentioning

confidence: 99%

Auxotrophy in rhizobia revisited

Yadav

2007

Indian J Microbiol

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Among the various types of mutations studied in rhizobia, the auxotrophic mutations (which confer on the mutants the inability to synthesize certain essential substances such as amino acids, vitamins and nucleic acids), are the most favoured ones as these can be used as suitable markers for genetic analysis. An important property of rhizobia is their effectiveness i.e. their ability to fi x atmospheric nitrogen into ammonia within the nodule. Special interest in this category of mutations by rhizobial geneticists is due to the fact that there is a strong correlation between the metabolic defects and the ineffectiveness (Nod -and/or Fix -) of the rhizobial strains. Auxotrophic mutants of various species of rhizobia with defects in the synthesis of nucleic bases, vitamins and amino acids have been obtained by mutagenising with physical, chemical and Tn5 mutagens. These mutants have been used in mapping studies as well as in establishing a correlation between its metabolic requirement and symbiotic relationship with the host plant. The present review deals with the isolation of auxotrophs, and their genetic, biochemical and symbiotic characterization. The review also encompasses the studies on the elucidation of biosynthetic pathways of nutritional substances in rhizobia.

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Bacterial Protoplasts Induced by Penicillin

Cited by 302 publications

References 8 publications

Mode of Action of Megacin

Mode of Action of Megacin

Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action

Auxotrophy in rhizobia revisited

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