Mutations Affecting Penicillin-binding Proteins 2a, 2b and 3 in Bacillus subtilis Alter Cell Shape and Peptidoglycan Metabolism

Shohayeb, Mohamed; Chopra, Ian

doi:10.1099/00221287-133-7-1733

Cited by 14 publications

(23 citation statements)

References 22 publications

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“…It is well-known that penicillin and other 3-lactam antibiotics inhibit septum formation of bacterial cells and cause aberrant morphology (11,16). Similar effects have also been observed with B. subtilis mutants that are defective in penicillin-binding proteins 2a, 2b, and 3 (23).…”

Section: Discussionsupporting

confidence: 65%

Lysis and aberrant morphology of Bacillus subtilis cells caused by surfactants and their relation to autolysin activity

Tsuchido

Svarachorn

Soga

et al. 1990

Antimicrob Agents Chemother

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The surfactants tested in this study lysed Bacilus subtilis 168 cells at the logarithmic growth phase. Results obtained with inhibitors and a mutant that had defective autolytic enzymes suggested that cell lysis resulted from the deregulation of autolysin activity. The addition of surfactants at sublytic concentrations produced twisted cells, filamented cells, or both. Autolysins extracted with 5 M LiCl from the cell wall fraction and lysozyme added to cells that were treated with surfactants restored the apparently normal cell rod morphology, suggesting that surfactants interfere with the role of autolysins in normal construction of the cell envelope. The rates of cellular autolysis and autolysin activity remaining in growing cells after exposure to a surfactant at a sublytic concentration decreased, although the rate of turnover of cell wall peptidoglycan was the same as that of control cells. Surfactants were suggested to interact with the regulatory system of autolysins and, thus, to affect the activities of autolysins in B. subls cells and to cause either morphological changes or cell autolysis, depending on the concentration of surfactants.

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Section: Discussionsupporting

confidence: 65%

Lysis and aberrant morphology of Bacillus subtilis cells caused by surfactants and their relation to autolysin activity

Tsuchido

Svarachorn

Soga

et al. 1990

Antimicrob Agents Chemother

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“…As a consequence of APF overproduction, the cells of L. gasseri 4B2(pVM23) and 4B2(pVM24) became twisted and enlarged in diameter. A similar twisted cell shape phenotype was observed with mutants of penicillin binding protein PBP2a, which is involved in peptidoglycan production in Bacillus subtilis (28). Also, other mutations that influence peptidoglycan production cause different changes in the shape of B. subtilis (28) and E. coli (20,21,28,30,35) cells.…”

Section: Discussionsupporting

confidence: 49%

“…A similar twisted cell shape phenotype was observed with mutants of penicillin binding protein PBP2a, which is involved in peptidoglycan production in Bacillus subtilis (28). Also, other mutations that influence peptidoglycan production cause different changes in the shape of B. subtilis (28) and E. coli (20,21,28,30,35) cells. Altered cell wall composition may lead to changes in the affinity of antibiotics for their target or their susceptibility to their target and make the cells more or less sensitive to cell wall-targeted antibiotics.…”

Section: Discussionsupporting

confidence: 49%

Contribution of Aggregation-Promoting Factor to Maintenance of Cell Shape in Lactobacillus gasseri 4B2

et al. 2003

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Aggregation-promoting factor (APF) was originally described as a protein involved in the conjugation and autoaggregation of Lactobacillus gasseri 4B2, whose corresponding apf gene was cloned and sequenced. In this report, we identified and sequenced an additional apf gene located in the region upstream of the previously published one. Inactivation of both apf genes was unsuccessful, indicating that APF function may be essential for the cell. Overproduction of APF proteins caused drastic alteration in the cell shape of this strain. These cells were irregular, twisted, enlarged, and tightly bound in unbreakable clumps of chains. Down-regulation of APF synthesis was achieved by cloning of the apf2 promoter region on a high-copy-number plasmid, which recruited a putative apf activator. As a consequence, the shape of the corresponding recombinant cells was elongated (filamentous) and cell division sites were no longer visible. None of the induced changes in APF production levels was clearly correlated with modifications of the aggregation phenotype. This report shows, for the first time, that APF proteins are mainly critical for L. gasseri 4B2 cell shape maintenance.Lactic acid bacteria are normal inhabitants of the human oral cavity and gastrointestinal (GI) and urogenital tracts. Interest in the health-promoting effects of specific lactic acid bacterial strains has increased in recent years (10, 12). Survival and persistence of probiotic bacteria in the human GI tract is often reported to provide them a competitive advantage. One of the proposed mechanisms that could increase the potential of bacteria to survive and persist in the GI tract is their ability to aggregate (13). However, this hypothesis has never been confirmed.To study the importance of aggregation, we chose an aggregating strain, Lactobacillus gasseri 4B2 (previously classified as L. plantarum 4B2), whose 32-kDa aggregation-promoting factor (APF) has already been described (25). This protein was purified from the culture supernatant as one of the most abundant proteins. The function of APF as a factor of aggregation was shown in vitro. After three subsequent washing steps, L. gasseri 4B2 lost its ability to aggregate. Addition of purified APF or of filtered supernatant reaggregated the washed cells. Furthermore, the role of APF in conjugation was also demonstrated (25). The frequency of pAM␤1 conjugal transfer (among Lactobacillus species whose aggregation is APF dependent) was increased upon addition of L. gasseri 4B2 filtered supernatant to the mating mixture. Since neither the apf gene nor any apf mutant was available, the exact physiological role of APF could not be demonstrated. Subsequent N-terminal sequencing of the L. gasseri 4B2 APF protein enabled the cloning and sequencing of the apf gene (accession no. Y08498; L. Morelli et al., direct submission).Recently, we showed that four L. johnsonii and two L. gasseri strains contain two apf genes in their genomes (34). Analysis of the gene organization, amino acid composition, and physical propert...

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“…There are at least 16 PBPs in B. subtilis (not including YvbJ) and their functions are redundant and overlapping (Sauvage et al, 2008). They are involved in synthesis and degradation of the peptidoglycan (reviewed in Sauvage et al, 2008), cell elongation and morphology (Shohayeb and Chopra, 1987;Wei et al, 2003), division (Yanouri et al, 1993), and sporulation (Sowell and Buchanan, 1983;Daniel et al, 1994;Popham et al, 1999;McPherson et al, 2001). yvbJ mutant cells had a normal appearance as visualized by phase microscopy, indicating that if there was any defect in cell division or morphology, it was not visually obvious.…”

Section: Characterization Of Yvbjmentioning

confidence: 99%

Identification of host genes that affect acquisition of an integrative and conjugative element in Bacillus subtilis

Johnson

Grossman

2014

Molecular Microbiology

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Summary Conjugation, a major type of horizontal gene transfer in bacteria, involves transfer of DNA from a donor to a recipient using donor-encoded conjugation machinery. Using a high throughput screen (Tn-seq), we identified genes in recipients that contribute to acquisition of the integrative and conjugative element ICEBs1 by Bacillus subtilis. We found that null mutations in some genes caused an increase, and others a decrease in conjugation efficiency. Some mutations affected conjugation only when present in recipients. Other mutations affected conjugation when present in donors or recipients. Most of the genes identified are known or predicted to affect the cell envelope. Several encode enzymes involved in phospholipid biosynthesis and one encodes a homolog of penicillin binding proteins. Two of the genes identified also affected conjugation of Tn916, indicating that their roles in conjugation may be general. We did not identify any genes in recipients that were essential for ICEBs1 conjugation, indicating that if there are such genes, then these are either essential for cell growth or redundant. Our results indicate that acquisition of ICEBs1, and perhaps other conjugative elements, is robust and not easily avoided by mutation and that several membrane-related functions affect the efficiency of conjugation.

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Mutations Affecting Penicillin-binding Proteins 2a, 2b and 3 in Bacillus subtilis Alter Cell Shape and Peptidoglycan Metabolism

Cited by 14 publications

References 22 publications

Lysis and aberrant morphology of Bacillus subtilis cells caused by surfactants and their relation to autolysin activity

Lysis and aberrant morphology of Bacillus subtilis cells caused by surfactants and their relation to autolysin activity

Contribution of Aggregation-Promoting Factor to Maintenance of Cell Shape in Lactobacillus gasseri 4B2

Identification of host genes that affect acquisition of an integrative and conjugative element in Bacillus subtilis

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