Osmotic Properties of Protoplasts of Micrococcus lysodeikticus

Gilby, A.R.; Few, A. V.

doi:10.1099/00221287-20-2-321

Cited by 14 publications

(12 citation statements)

References 6 publications

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“…Caprylic acid did not lyse protoplasts but induced their contraction as shown by increases in the O.D. (Gilby BE Few, 1959) and observed microscopically and the rate at which this occurred was dependent on the fatty acid concentration. Capric acid (5.0 m) produced an initial rapid increase in the O.D.…”

Section: Lysis Of Protoplasts Of B Megaterium By Caprylic and Capricmentioning

confidence: 87%

Physicochemical Effects of Long Chain Fatty Acids on Bacterial Cells and their Protoplasts

Galbraith

Miller

1973

Journal of Applied Bacteriology

129

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Fatty acids of chain length > C,, induced lysis of protoplasts at pH 7.4 when the concentration was nearly bactericidd. At p H 6, lauric and linoleic acids produced lysis above bactericidal concentrations but, at pH 8, lysk was produced by the same acids below bactericidal concentrations. The lysis was immediate a t p H 8, but at pH 6 the effect was preceded by contraction of protoplasts. At pH 7.4 the order of lytic activity between individual fatty acids was similar to that of bactericidal activity and the response of protoplasts of Bacillwr megaterium relative to those of 2Mimcoccus lyeodeikticus reflected differences in bactericidal sensitivity though whole cells were much less sensitive to fatty acid-induced leakage effects then protoplasts. Reversal agents antagonized the lysis of protoplasts by fatty acids. A physicochemical basis for the action of fatty acids and reversal agents on protoplasts and whole cells is discussed.ANTIBACTERIAL EIWECTS of long chain fatty acids have already been discussed in relation to bactericidal activity and physicochemical properties in solution (Galbraith, Miller, Paton & Thompson, 1971 ;Galbraith & Miller, 1973a).Several workers have produced evidence which suggests that antibacterial compounds with lipophilic and hydrophilic properties act on the cytoplasmic membrane (Hugo, 1967; Salton, 1968). The most convenient method of investigating the interaction between these antibacterial compounds and the bacterial membrane involves the use of protoplasts and spheroplasts. Gilby & Few (1957, 1960) have demonstrated the lysis of protoplasts by surface active agents and correlated the lytic activity with antibacterial activity on whole bacterial cells. In previous work with long chain fatty acids (Galbraith & Miller, 1973a) the reversible uptake of 14C labelled fatty acids by bacterial cells and protoplasts also indicated that the probable site of action of the fatty acids was the cytoplasmic membrane and so in the present work the lysis of protoplasts has been studied in order to investigate the relationship between antibacterial action and phyaicochemical activity on the membrane. The studies have included the effects of pH, aliphatic chain length, reversal agents and the sensitivity of the individual bacterial species which were used to determine bactericidal activity and uptake. An attempt was also made to investigate the physicochemical effects of fatty acids on whole cells in order to determine whether the overall response is similar to that found with protoplasts in the absence of the cell wall. Materials and MethodsCultures and media The organisms used were Bacillus megaterium NCIB 9521 and Micrococcus lysodeiktieus NCIB 9278. Bacterial suspensions and protoplasts of B. megaterium were prepared [6471

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Section: Lysis Of Protoplasts Of B Megaterium By Caprylic and Capricmentioning

confidence: 87%

Physicochemical Effects of Long Chain Fatty Acids on Bacterial Cells and their Protoplasts

Galbraith

Miller

1973

Journal of Applied Bacteriology

129

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“…Bacteria are difficult to plasmolyse and the extent of shrinkage is usually slight (Weibull, 1956). Volumes of protoplasts vary slightly with the external conditions, the osmotically inert fraction of the total volume being 36 yo for protoplasts of Bacillus megatmiurn (Weibull, 1955) and 76 yo for those of Micrococcus Zysodeikticus (Gilby & Few, 1959). The process of vacuolation of the spheroplasts is rather slow; this probably accounts for the continuous changes in the optical densities of their suspensions (Fig.…”

Section: Discussionmentioning

confidence: 99%

The Preparation and Properties of Spheroplasts of Aerobacter aerogenes

Gebicki¹,

James²

1960

Journal of General Microbiology

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SUMMARYCells of A e r o b e aerogenes growing in a nutrient medium were lysed by 1000 u. penicillin/ml. When the medium contained penicillin and sucrose, bacterial mass continued to increase on incubation, although no further cell division took place. After growth for 3 hr. in the presence of penicillin, all the rod-shaped bacteria were converted to fragile spheroplasts. The internal osmotic pressure of the spheroplasts was estimated by direct counts of the intact cells in solutions containing various concentrations of sucrose, sodium chloride or mixed phosphates. Measurements of optical densities of suspensions were unsuitable for the estimation of the numbers of spheroplasts. Morphological study suggested the existence of a spheroplast cell wall outside the protoplasmic membrane.

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“…However, increased numbers of phagocytes were not observed in the medulla when the kidneys of animals undergoing diuresis were examined histologically at various intervals after Staphylococcal challenge. Finally, these natural defenses, namely, antibody, complement, and lysozyme, can injure the cell wall of most urinary pathogens so that they form protoplasts (25)(26)(27). These protoplasts are lysed in a hypotonic or isotonic environment, but are preserved in hypertonic solutions (28).…”

Section: Discussionmentioning

confidence: 99%

Prevention of Pyelonephritis by Water Diuresis: Evidence for the Role of Medullary Hypertonicity in Promoting Renal Infection *

Andriole¹,

Epstein²

1965

J. Clin. Invest.

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The medulla of the kidney is much more susceptible to infection than the cortex (1-5). The unique vulnerability of the renal medulla has been ascribed in the past to its anatomical location (6), to its relatively poor circulation (7), and to its chemical composition, in particular to its content of ammonia and ammonia-producing enzymes that inhibit the action of complement (8).The present experiments suggest that the susceptibility of the medulla to infection is determined at least in part by another of its properties, namely, its habitual hypertonicity. A simple method for inducing chronic water diuresis in rats has provided a model for studying many aspects of experimental pyelonephritis. Renal infection in rats can be prevented by decreasing the normally hypertonic environment of the renal medulla through sustained water diuresis. MethodsAnimals. White female Sprague-Dawley strain rats, weighing 150 to 200 g were used. Animals were weighed on the first and last days of each experiment.All animals were fed Purina lab chow pellets and tap water ad libitum.Water diuresis. Chronic water diuresis was induced in rats by the simple method of adding 5%o glucose to their drinking water. The volume of fluid intake and *

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Osmotic Properties of Protoplasts of Micrococcus lysodeikticus

Cited by 14 publications

References 6 publications

Physicochemical Effects of Long Chain Fatty Acids on Bacterial Cells and their Protoplasts

Physicochemical Effects of Long Chain Fatty Acids on Bacterial Cells and their Protoplasts

The Preparation and Properties of Spheroplasts of Aerobacter aerogenes

Prevention of Pyelonephritis by Water Diuresis: Evidence for the Role of Medullary Hypertonicity in Promoting Renal Infection *

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