Relationship of shape to initiation of new sites of envelope growth in Streptococcus faecium cells treated with beta-lactam antibiotics

Higgins, M. L.; Ferrero, Marta; Daneo-Moore, L

doi:10.1128/jb.167.2.562-569.1986

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…1). faecalis have been shown to be inhibited by /3-1actam antibiotics [14]. If so the protein content of the supernatant fluids from protoplast preparations from antibiotic treated cultures should be higher than those from control untreated ones.…”

Section: Resultsmentioning

confidence: 99%

Spherical and rod shaped protoplasts from β-lactam antibiotic treated cultures of Bacillus subtilis

Wright¹

1988

FEMS Microbiology Letters

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Addition of β‐lactams to exponentially growing cultures of an autolytically deficient Bacillus subtilis metc3 lyt‐2 strain FJ6 caused increase in optical density to stop after 1 h when it had about doubled, and thereafter to remain constant for at least 6 h. The number of protoplasts to be derived per unit dry weight of bacteria started to fall when the antibiotic was added and after 1 h had reached 50% of the initial value. Also during the first hour but after a lag of 20–30 min an increasing number of membrane bound rod shaped protoplasts were seen among the normal spherical ones. These swelled to spheres and ultimately burst if the concentration of sucrose in the suspending fluid was gradually reduced. These results would be best explained by rapid inhibition of initiation of cell division followed by membrane damage to an increasing proportion of cells.

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Section: Resultsmentioning

confidence: 99%

Spherical and rod shaped protoplasts from β-lactam antibiotic treated cultures of Bacillus subtilis

Wright¹

1988

FEMS Microbiology Letters

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“…Shockman (27) and Blumberg and Strominger (2) enlarged on this hypothesis, adding that the poorly cross-linked wall resulting from penicillin action was too weak to resist the strain. This has recently been emphasized with studies of S. faecium (7). On the other hand, Tomasz (29) focused on the phenomenon of tolerance.…”

Section: Discussionmentioning

confidence: 99%

Turgor pressure responses of a gram-negative bacterium to antibiotic treatment, measured by collapse of gas vesicles

Pinette

Koch

1988

J Bacteriol

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The internal hydrostatic pressure of Ancylobacter aquaticus was measured by collapsing the gas vesicles with an externally applied pressure. Turgor pressure was measured in conjunction with various antibiotic treatments to elucidate some aspects of the biophysics of gram-negative cell wall function. Differences in the effects of these drugs either alone or in combination with other treatments were related to known biochemical activities of these drugs. Our previous work, demonstrating a heterogeneous cellular response to beta-lactam antibodies, was confirmed and extended. Most of the cell wall growth-inhibiting antibiotics resulted in some cells (those in component I) developing a higher pressure, while the remainder (those in component II) lost turgor. Although the fraction of the cells in each component varied a little from subculture to subculture, it did not vary with time or choice of antibiotic treatment. Mecillinam gave a nearly monophasic response. All antibiotics blocking macromolecular synthesis gave monophasic curves. The 50% collapse pressure in some cases, however, was lower higher, or the same as the control.

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“…It should be noted, however, that separation of those cells affected by the drug very early in the division cycle was obviously somewhat hampered (Fig. 3, column 2), reminiscent of the situation described for streptococci (19).…”

Section: ])mentioning

confidence: 99%

Onset of penicillin-induced bacteriolysis in staphylococci is cell cycle dependent

et al. 1989

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Synchronously growing staphylococci were treated with "Ilytic"concentrations of penicillin at different stages of their division cycle. Coulter Counter measurements and light microscopy were used to determine the onset of bacteriolysis. Independent of the stage of the division cycle at which peniciBin was added, (i) the ceUs were always able to perform the next cel division; (ii) the folowing division, however, did not take place; and (iii) instead, at this time, when the onset of the subsequent cell separation was observed in control cultures, lysis of the penicillin-treated cells occurred. These results support a recent model (P. Giesbrecht, H. Labischinski, and J. Wecke, Arch. Microbiol. 141:315-324, 1985) explaining penicillin-induced bacteriolysis of staphylococci as the result of a special morphogenetic mistake during cross wal formation.The mechanism of bacteriolysis by penicillin has been the subject of research for a long time. The many details brought forth by biochemical studies led to different explanations for the lytic death of bacteria. Since the mid-1960s it has been known that penicillin reduces the degree of cross-linking of the bacterial cell wall (28), and the conclusion was that a therefore less-resistant cell wall would no longer be capable of withstanding the relatively high osmotic pressures inside the bacteria. Other investigations showed that with pneumococci, treatment with penicillin induced the release of inhibitors of their autolytic wall enzymes; the resulting triggering of these wall enzymes was regarded as being responsible for lysis (29).In contrast, it has been reported (24, 30) that in the course of a penicillin treatment the autolytic activity of staphylococci decreased rather than increased and that the synthesis of wall material was hardly affected by lytic concentrations of penicillin. Electron microscopic results which showed that even with optimal "lytic" doses of penicillin, staphylococci could build a more or less functioning cross wall (15) and the discovery of new extraplasmatic vesicular structures led to a new model of penicillin-induced bacteriolysis proposed by 13,21). According to this model, penicillin-induced bacteriolysis results from the punching of a few minute holes into the peripheral wall due to the lytic activity of these vesicular structures, which have been named murosomes. Under nonantibiotic conditions, the murosomes perform an essential function: they trigger the cutting process, the first step of cell separation in staphylococci after completion of cell division (13, 21). The lethal event at the relatively low lytic penicillin G concentration (about 0.1 ,ug/ml for the staphylococcal strain used) seemed to be caused by an abnormal local distribution of the wall material synthesized during penicillin G treatment; lytic death occurred as the result of such a special morphogenetic mistake during cross wall formation, which regularly took place when the onset of the normal cell separation process was no longer preceded by sufficient cross wall assembl...

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Relationship of shape to initiation of new sites of envelope growth in Streptococcus faecium cells treated with beta-lactam antibiotics

Cited by 5 publications

References 17 publications

Spherical and rod shaped protoplasts from β-lactam antibiotic treated cultures of Bacillus subtilis

Spherical and rod shaped protoplasts from β-lactam antibiotic treated cultures of Bacillus subtilis

Turgor pressure responses of a gram-negative bacterium to antibiotic treatment, measured by collapse of gas vesicles

Onset of penicillin-induced bacteriolysis in staphylococci is cell cycle dependent

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