Role of penicillin-binding proteins in the viability, morphology, stress tolerance and pathogenicity of Clavibacter michiganensis

2020 ◽  
Author(s):  
Xing Chen ◽  
Kaihong Bai ◽  
Qingyang Lyu ◽  
Na Jiang ◽  
Jianqiang Li ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Protective Role ◽  
Vbnc State ◽  
Clavibacter Michiganensis ◽  
Penicillin Binding Proteins ◽  
Class B ◽  
Increased Sensitivity ◽  
Type C ◽  
Adverse Environmental Conditions

Previous research has shown that penicillin-binding proteins (PBPs), enzymes involved in peptidoglycan (PG) assembly, could play an important role during the induction of viable but non-culturable (VBNC) state, which allows non-spore forming bacteria to survive adverse environmental conditions. The current study found that C. michiganensis has a total of seven PBP proteins. Mutant analysis indicated that deletion of either of the class B PBPs was lethal, and that the class A PBP, PBPC, had an important role in PG synthesis, with the ΔpbpC mutant having an altered cellular morphology that resulted in longer cells that were swollen at one end, and had thinner cell walls. The ΔpbpC mutant was also found to produce mucoid colonies in solid culture and a lower final cell titer in liquid medium, as well as having increased sensitivity to osmotic stress and lysozyme treatment, and surprisingly increased pathogenicity. The double mutant, ΔdacB/ΔpbpE also had a slightly altered phenotype resulting in longer cells. Further analysis revealed that both mutants had increased sensitivity to copper, which resulted in quicker induction into the VBNC state. However, only the ΔpbpC mutant had significantly reduced survivorship in the VBNC state. The study also confirmed the VBNC state significantly improved the survivorship of wild-type C. michiganensis cells in response to environmental stresses, and systemically demonstrated the protective role of the VBNC state in C. michiganensis, which is an important finding regarding its epidemiology, and has serious implications for disease management.

scholarly journals Role of Penicillin-Binding Proteins in the Initiation of the AmpC β-Lactamase Expression inEnterobacter cloacae

2000 ◽  
Vol 44 (1) ◽  
pp. 169-172 ◽  
Author(s):  
Dieter Pfeifle ◽  
Eva Janas ◽  
Bernd Wiedemann
Keyword(s):  
Escherichia Coli ◽  
Binding Proteins ◽  
Penicillin Binding Proteins

ABSTRACT Penicillin-binding proteins (PBPs) are involved in the regulation of β-lactamase expression by determining the level of anhydromuramylpeptides in the periplasmatic space. It was hypothesized that one or more PBPs act as a sensor in the β-lactamase induction pathway. We have performed induction studies with Escherichia coli mutants lacking one to four PBPs withdd-carboxypeptidase activity. Therefore, we conclude that a strong β-lactamase inducer must inhibit alldd-carboxypeptidases as well as the essential PBPs 1a, 1b, and/or 2.

scholarly journals Rod Shape Determination by the Bacillus subtilis Class B Penicillin-Binding Proteins Encoded by pbpA and pbpH

2003 ◽  
Vol 185 (16) ◽  
pp. 4717-4726 ◽  
Author(s):  
Yuping Wei ◽  
Teresa Havasy ◽  
Derrell C. McPherson ◽  
David L. Popham
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Binding Proteins ◽  
Structural Integrity ◽  
Sequence Similarity ◽  
Inducible Promoter ◽  
Penicillin Binding Proteins ◽  
Peptidoglycan Cell Wall ◽  
Class B ◽  
Shape Determination

ABSTRACT The peptidoglycan cell wall determines the shape and structural integrity of a bacterial cell. Class B penicillin-binding proteins (PBPs) carry a transpeptidase activity that cross-links peptidoglycan strands via their peptide side chains, and some of these proteins are directly involved in cell shape determination. No Bacillus subtilis PBP with a clear role in rod shape maintenance has been identified. However, previous studies showed that during outgrowth of pbpA mutant spores, the cells grew in an ovoid shape for several hours before they recovered and took on a normal rod shape. It was postulated that another PBP, expressed later during outgrowth, was able to compensate for the lack of the pbpA product, PBP2a, and to guide the formation of a rod shape. The B. subtilis pbpH (ykuA) gene product is predicted to be a class B PBP with greatest sequence similarity to PBP2a. We found that a pbpH-lacZ fusion was expressed at very low levels in early log phase and increased in late log phase. A pbpH null mutant was indistinguishable from the wild-type, but a pbpA pbpH double mutant was nonviable. When pbpH was placed under the control of an inducible promoter in a pbpA mutant, viability was dependent on pbpH expression. Growth of this strain in the absence of inducer resulted in conversion of the cells from rods to ovoid/round shapes and lysis. We conclude that PBP2a and PbpH play redundant roles in formation of a rod-shaped peptidoglycan cell wall.

scholarly journals A Mother Cell-Specific Class B Penicillin-Binding Protein, PBP4b, in Bacillus subtilis

2004 ◽  
Vol 186 (1) ◽  
pp. 258-261 ◽  
Author(s):  
Yuping Wei ◽  
Derrell C. McPherson ◽  
David L. Popham
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Mother Cell ◽  
Binding Proteins ◽  
Binding Protein ◽  
Specific Class ◽  
Penicillin Binding Protein ◽  
Penicillin Binding Proteins ◽  
Peptidoglycan Structure ◽  
Class B

ABSTRACT The Bacillus subtilis genome encodes 16 penicillin-binding proteins (PBPs), some of which are involved in synthesis of the spore peptidoglycan. The pbpI (yrrR) gene encodes a class B PBP, PBP4b, and is transcribed in the mother cell by RNA polymerase containing σE. Loss of PBP4b, alone and in combination with other sporulation-specific PBPs, had no effect on spore peptidoglycan structure.

Investigations on the role of CH…O interactions and its impact on stability and specificity of penicillin binding proteins

2015 ◽  
Vol 65 ◽  
pp. 85-92 ◽  
Author(s):  
P. Lavanya ◽  
Sudha Ramaiah ◽  
Harpeet Singh ◽  
Renu Bahadur ◽  
Anand Anbarasu
Keyword(s):  
Binding Proteins ◽  
Penicillin Binding Proteins

scholarly journals Role of AmpD, OprF and penicillin-binding proteins in β-lactam resistance in clinical isolates of Pseudomonas aeruginosa

2007 ◽  
Vol 56 (6) ◽  
pp. 809-814 ◽  
Author(s):  
Simona Bratu ◽  
David Landman ◽  
Jyoti Gupta ◽  
John Quale
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Binding Proteins ◽  
Clinical Isolates ◽  
Rt Pcr ◽  
Penicillin Binding Proteins ◽  
Genomic Deletions ◽  
Cephalosporin Resistance ◽  
Outer Membrane Permeability

In this study, the mechanisms leading to increased chromosomal AmpC β-lactamase expression and the contributory roles of the outer-membrane protein OprF and penicillin-binding proteins were analysed in 33 characterized clinical isolates of Pseudomonas aeruginosa. The genes ampD and ampE were analysed by PCR and DNA sequencing. Expression of the gene oprF was assessed using real-time RT-PCR, and penicillin-binding proteins were analysed using a chemiluminescence assay. Several of the isolates with increased ampC expression had major deletions affecting ampD, although in some isolates the mechanism of increased ampC expression could not be ascertained. Occasional isolates had increased expression of both ampC and oprF but remained susceptible to cephalosporins, suggesting that increased β-lactamase activity could not offset increased outer-membrane permeability. There were no discernible changes in penicillin-binding proteins. Genomic deletions in ampD were observed in selected clinical isolates of P. aeruginosa with increased expression of the AmpC β-lactamase. For some isolates, cephalosporin resistance was dependent upon the interplay of ampC and oprF expression.

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