scholarly journals Bedaquiline Eliminates Bactericidal Activity of β-Lactams against Mycobacterium abscessus

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Marissa Lindman ◽  
Thomas Dick
Keyword(s):  
Cell Wall ◽  
Treatment Outcome ◽  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Bactericidal Activity ◽  
Mycobacterium Abscessus ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Lung Infections ◽  
Synthase Inhibitor

ABSTRACT The β-lactams imipenem and cefoxitin are used for the treatment of Mycobacterium abscessus lung infections. Here, we show that these cell wall synthesis inhibitors trigger a lethal bacterial ATP burst by increasing oxidative phosphorylation. Cotreatment of M. abscessus with the antimycobacterial ATP synthase inhibitor bedaquiline suppresses this ATP burst and eliminates the bactericidal activity of β-lactams. Thus, the addition of bedaquiline to β-lactam-containing regimes may negatively affect treatment outcome.

scholarly journals Genome-Wide Screening Identifies Six Genes That Are Associated with Susceptibility to Escherichia coli Microcin PDI

2015 ◽  
Vol 81 (20) ◽  
pp. 6953-6963 ◽  
Author(s):  
Zhe Zhao ◽  
Lauren J. Eberhart ◽  
Lisa H. Orfe ◽  
Shao-Yeh Lu ◽  
Thomas E. Besser ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Atp Synthase ◽  
Disulfide Bonds ◽  
Gene Knockout ◽  
Single Gene ◽  
Site Directed Mutagenesis ◽  
Content Type ◽  
E Coli ◽  
Synthase Inhibitor ◽  
Loss Of Susceptibility

ABSTRACTThe microcin PDI inhibits a diverse group of pathogenicEscherichia colistrains. Coculture of a single-gene knockout library (BW25113;n= 3,985 mutants) against a microcin PDI-producing strain (E. coli25) identified six mutants that were not susceptible (ΔatpA, ΔatpF, ΔdsbA, ΔdsbB, ΔompF, and ΔompR). Complementation of these genes restored susceptibility in all cases, and the loss of susceptibility was confirmed through independent gene knockouts inE. coliO157:H7 Sakai. Heterologous expression ofE. coliompFconferred susceptibility toSalmonella entericaandYersinia enterocoliticastrains that are normally unaffected by microcin PDI. The expression of chimeric OmpF and site-directed mutagenesis revealed that the K47G48N49region within the first extracellular loop ofE. coliOmpF is a putative binding site for microcin PDI. OmpR is a transcriptional regulator forompF, and consequently loss of susceptibility by the ΔompRstrain most likely is related to this function. Deletion of AtpA and AtpF, as well as AtpE and AtpH (missed in the original library screen), resulted in the loss of susceptibility to microcin PDI and the loss of ATP synthase function. Coculture of a susceptible strain in the presence of an ATP synthase inhibitor resulted in a loss of susceptibility, confirming that a functional ATP synthase complex is required for microcin PDI activity. Intransexpression ofompFin the ΔdsbAand ΔdsbBstrains did not restore a susceptible phenotype, indicating that these proteins are probably involved with the formation of disulfide bonds for OmpF or microcin PDI.

scholarly journals Interplay between Antibiotic Efficacy and Drug-Induced Lysis Underlies Enhanced Biofilm Formation at Subinhibitory Drug Concentrations

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Wen Yu ◽  
Kelsey M. Hallinen ◽  
Kevin B. Wood
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Cell Lysis ◽  
Living Cells ◽  
Cell Wall Synthesis ◽  
Drug Induced ◽  
Trade Off ◽  
Content Type ◽  
Subinhibitory Concentrations ◽  
Antibiotic Efficacy

ABSTRACTSubinhibitory concentrations of antibiotics have been shown to enhance biofilm formation in multiple bacterial species. While antibiotic exposure has been associated with modulated expression of many biofilm-related genes, the mechanisms of drug-induced biofilm formation remain a focus of ongoing research efforts and may vary significantly across species. In this work, we investigate antibiotic-induced biofilm formation inEnterococcus faecalis, a leading cause of nosocomial infections. We show that biofilm formation is enhanced by subinhibitory concentrations of cell wall synthesis inhibitors but not by inhibitors of protein, DNA, folic acid, or RNA synthesis. Furthermore, enhanced biofilm is associated with increased cell lysis, increases in extracellular DNA (eDNA) levels, and increases in the density of living cells in the biofilm. In addition, we observe similar enhancement of biofilm formation when cells are treated with nonantibiotic surfactants that induce cell lysis. These findings suggest that antibiotic-induced biofilm formation is governed by a trade-off between drug toxicity and the beneficial effects of cell lysis. To understand this trade-off, we developed a simple mathematical model that predicts changes in antibiotic-induced biofilm formation due to external perturbations, and we verified these predictions experimentally. Specifically, we demonstrate that perturbations that reduce eDNA (DNase treatment) or decrease the number of living cells in the planktonic phase (a second antibiotic) decrease biofilm induction, while chemical inhibitors of cell lysis increase relative biofilm induction and shift the peak to higher antibiotic concentrations. Overall, our results offer experimental evidence linking cell wall synthesis inhibitors, cell lysis, increased eDNA levels, and biofilm formation inE. faecaliswhile also providing a predictive quantitative model that sheds light on the interplay between cell lysis and antibiotic efficacy in developing biofilms.

scholarly journals Bacteriophage SP01 Gene Product 56 Inhibits Bacillus subtilis Cell Division by Interacting with FtsL and Disrupting Pbp2B and FtsW Recruitment

2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Gene Product ◽  
Fluorescent Protein ◽  
Lytic Bacteriophage ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Ftsz Ring ◽  
Green Fluorescent

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.

scholarly journals Transcriptional Inhibition of the F1F0-Type ATP Synthase Has Bactericidal Consequences on the Viability of Mycobacteria

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Matthew B. McNeil ◽  
Heath W. K. Ryburn ◽  
Liam K. Harold ◽  
Justin F. Tirados ◽  
Gregory M. Cook
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Atp Synthase ◽  
Bactericidal Activity ◽  
Mycobacterium Smegmatis ◽  
Drug Target ◽  
Potent Inhibitor ◽  
Time Dependent ◽  
Content Type ◽  
Transcriptional Inhibition ◽  
Delayed Time

ABSTRACT Bedaquiline, an inhibitor of the mycobacterial ATP synthase, has revolutionized the treatment of Mycobacterium tuberculosis infection. Although a potent inhibitor, it is characterized by poorly understood delayed time-dependent bactericidal activity. Here, we demonstrate that in contrast to bedaquiline, the transcriptional inhibition of the ATP synthase in M. tuberculosis and Mycobacterium smegmatis has rapid bactericidal activity. These results validate the mycobacterial ATP synthase as a drug target with the potential for rapid bactericidal activity.

scholarly journals TBAJ-876 Displays Bedaquiline-Like Mycobactericidal Potency without Retaining the Parental Drug’s Uncoupler Activity

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Jickky Palmae Sarathy ◽  
Priya Ragunathan ◽  
Christopher B. Cooper ◽  
Anna M. Upton ◽  
Gerhard Grüber ◽  
...  
Keyword(s):  
Electron Transport ◽  
Atp Synthase ◽  
Mechanism Of Action ◽  
Bactericidal Activity ◽  
Atp Synthesis ◽  
Synthase Inhibitor ◽  
Time Kill

ABSTRACT The diarylquinoline F1FO-ATP synthase inhibitor bedaquiline (BDQ) displays protonophore activity. Thus, uncoupling electron transport from ATP synthesis appears to be a second mechanism of action of this antimycobacterial drug. Here, we show that the new BDQ analogue TBAJ-876 did not retain the parental drug’s protonophore activity. Comparative time-kill analyses revealed that both compounds exert the same bactericidal activity. These results suggest that the uncoupler activity is not required for the bactericidal activity of diarylquinolines.

scholarly journals Interaction of Platelets and Anidulafungin against Aspergillus fumigatus

2012 ◽  
Vol 57 (1) ◽  
pp. 626-628 ◽  
Author(s):  
Susanne Perkhofer ◽  
Barbara Striessnig ◽  
Bettina Sartori ◽  
Barbara Hausott ◽  
Helmut W. Ott ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Untreated Control ◽  
Germination Rate ◽  
Human Platelets ◽  
Cell Wall Synthesis ◽  
Content Type

ABSTRACTThe combination of platelets and anidulafungin at 0.03 μg/ml significantly (P< 0.05) reduced the germination rate and hyphal elongation inAspergillus fumigatuscompared to those with either anidulafungin only or an untreated control. Platelets decreased the expression of thefksgene, which plays an important role in cell wall synthesis. Our results suggest that human platelets plus anidulafungin might contribute to defense againstA. fumigatus.

scholarly journals An Alternative and Conserved Cell Wall Enzyme That Can Substitute for the Lipid II Synthase MurG

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
L. Zhang ◽  
K. Ramijan ◽  
V. J. Carrión ◽  
L. T. van der Aart ◽  
J. Willemse ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sequence Similarity ◽  
Streptomyces Coelicolor ◽  
Genomic Analysis ◽  
Environmental Harm ◽  
Cell Wall Synthesis ◽  
Precursor Molecule ◽  
Content Type ◽  
Lipid Ii ◽  
A Cell

ABSTRACT The cell wall is a stress-bearing structure and a unifying trait in bacteria. Without exception, synthesis of the cell wall involves formation of the precursor molecule lipid II by the activity of the essential biosynthetic enzyme MurG, which is encoded in the division and cell wall synthesis (dcw) gene cluster. Here, we present the discovery of a cell wall enzyme that can substitute for MurG. A mutant of Kitasatospora viridifaciens lacking a significant part of the dcw cluster, including murG, surprisingly produced lipid II and wild-type peptidoglycan. Genomic analysis identified a distant murG homologue, which encodes a putative enzyme that shares only around 31% amino acid sequence identity with MurG. We show that this enzyme can replace the canonical MurG, and we therefore designated it MglA. Orthologues of mglA are present in 38% of all genomes of Kitasatospora and members of the sister genus Streptomyces. CRISPR interference experiments showed that K. viridifaciens mglA can also functionally replace murG in Streptomyces coelicolor, thus validating its bioactivity and demonstrating that it is active in multiple genera. All together, these results identify MglA as a bona fide lipid II synthase, thus demonstrating plasticity in cell wall synthesis. IMPORTANCE Almost all bacteria are surrounded by a cell wall, which protects cells from environmental harm. Formation of the cell wall requires the precursor molecule lipid II, which in bacteria is universally synthesized by the conserved and essential lipid II synthase MurG. We here exploit the unique ability of an actinobacterial strain capable of growing with or without its cell wall to discover an alternative lipid II synthase, MglA. Although this enzyme bears only weak sequence similarity to MurG, it can functionally replace MurG and can even do so in organisms that naturally have only a canonical MurG. The observation that MglA proteins are found in many actinobacteria highlights the plasticity in cell wall synthesis in these bacteria and demonstrates that important new cell wall biosynthetic enzymes remain to be discovered.

The fungal-specific subunit i/j of F1FO-ATP synthase stimulates the pathogenicity of Candida albicans independent of oxidative phosphorylation

2020 ◽  
Author(s):  
Yajing Zhao ◽  
Yan Lyu ◽  
Yanli Zhang ◽  
Shuixiu Li ◽  
Yishan Zhang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Fungal Infections ◽  
Critical Role ◽  
Antifungal Drug ◽  
F1fo Atp Synthase

Abstract Invasive fungal infections are a major cause of human mortality due in part to a very limited antifungal drug arsenal. The identification of fungal-specific pathogenic mechanisms is considered a crucial step to current antifungal drug development and represents a significant goal to increase the efficacy and reduce host toxicity. Although the overall architecture of F1FO-ATP synthase is largely conserved in both fungi and mammals, the subunit i/j (Su i/j, Atp18) and subunit k (Su k, Atp19) are proteins not found in mammals and specific to fungi. Here, the role of Su i/j and Su k in Candida albicans was characterized by an in vivo assessment of the virulence and in vitro growth and mitochondrial function. Strikingly, the atp18Δ/Δ mutant showed significantly reduced pathogenicity in systemic murine model. However, this substantial defect in infectivity exists without associated defects in mitochondrial oxidative phosphorylation or proliferation in vitro. Analysis of virulence-related traits reveals normal in both mutants, but shows cell wall defects in composition and architecture in the case of atp18Δ/Δ. We also find that the atp18Δ/Δ mutant is more susceptible to attack by macrophages than wild type, which may correlate well with the abnormal cell wall function and increased sensitivity to oxidative stress. In contrast, no significant changes were observed in any of these studies for the atp19Δ/Δ. These results demonstrate that the fungal-specific Su i/j, but not Su k of F1FO-ATP synthase may play a critical role in C. albicans infectivity and represent another opportunity for new therapeutic target investigation. Lay Abstract This study aims to investigate biological functions of fungal-specific subunit i/j and subunit k of ATP synthase in C. albicans oxidative phosphorylation and virulence potential. Our results revealed that subunit i/j, and not subunit k, is critical for C. albicans pathogenicity.

scholarly journals Lysis of a Lactococcus lactis Dipeptidase Mutant and Rescue by Mutation in the Pleiotropic Regulator CodY

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Chenxi Huang ◽  
Jhonatan A. Hernandez-Valdes ◽  
Oscar P. Kuipers ◽  
Jan Kok
Keyword(s):  
Cell Wall ◽  
Amino Acid ◽  
Nitrogen Metabolism ◽  
Lactococcus Lactis ◽  
Cell Shape ◽  
Single Point Mutation ◽  
Binding Motif ◽  
Acid Uptake ◽  
Cell Wall Synthesis ◽  
Content Type

ABSTRACT Lactococcus lactis subsp. cremoris MG1363 is a model for the lactic acid bacteria (LAB) used in the dairy industry. The proteolytic system, consisting of a proteinase, several peptide and amino acid uptake systems, and a host of intracellular peptidases, plays a vital role in nitrogen metabolism and is of eminent importance for flavor formation in dairy products. The dipeptidase PepV functions in the last stages of proteolysis. A link between nitrogen metabolism and peptidoglycan (PG) biosynthesis was underlined by the finding that deletion of the dipeptidase gene pepV (creating strain MGΔpepV) resulted in a prolonged lag phase when the mutant strain was grown with a high concentration of glycine. In addition, most MGΔpepV cells lyse and have serious defects in their shape. This phenotype is due to a shortage of alanine, since adding alanine can rescue the growth and shape defects. Strain MGΔpepV is more resistant to vancomycin, an antibiotic targeting peptidoglycan d-Ala–d-Ala ends, which confirmed that MGΔpepV has an abnormal PG composition. A mutant of MGΔpepV was obtained in which growth inhibition and cell shape defects were alleviated. Genome sequencing showed that this mutant has a single point mutation in the codY gene, resulting in an arginine residue at position 218 in the DNA-binding motif of CodY being replaced by a cysteine residue. Thus, this strain was named MGΔpepVcodYR218C. Transcriptome sequencing (RNA-seq) data revealed a dramatic derepression in peptide uptake and amino acid utilization in MGΔpepVcodYR218C. A model of the connections among PepV activity, CodY regulation, and PG synthesis of L. lactis is proposed. IMPORTANCE Precise control of peptidoglycan synthesis is essential in Gram-positive bacteria for maintaining cell shape and integrity as well as resisting stresses. Although neither the dipeptidase PepV nor alanine is essential for L. lactis MG1363, adequate availability of either ensures proper cell wall synthesis. We broaden the knowledge about the dipeptidase PepV, which acts as a linker between nitrogen metabolism and cell wall synthesis in L. lactis.

scholarly journals D-Methionine and D-Phenylalanine Improve Lactococcus lactis F44 Acid Resistance and Nisin Yield by Governing Cell Wall Remodeling

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Hao Wu ◽  
Ershu Xue ◽  
Ning Zhi ◽  
Qianqian Song ◽  
Kairen Tian ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Lactococcus Lactis ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Acid Resistance ◽  
Cell Wall Synthesis ◽  
Nisin Production ◽  
Content Type ◽  
Nisin Yield

ABSTRACT Lactococcus lactis encounters various environmental challenges, especially acid stress, during its growth. The cell wall can maintain the integrity and shape of the cell under environmental stress, and d-amino acids play an important role in cell wall synthesis. Here, by analyzing the effects of 19 different d-amino acids on the physiology of L. lactis F44, we found that exogenously supplied d-methionine and d-phenylalanine increased the nisin yield by 93.22% and 101.29%, respectively, as well as significantly increasing the acid resistance of L. lactis F44. The composition of the cell wall in L. lactis F44 with exogenously supplied d-Met or d-Phe was further investigated via a vancomycin fluorescence experiment and a liquid chromatography-mass spectrometry assay, which demonstrated that d-Met could be incorporated into the fifth position of peptidoglycan (PG) muropeptides and d-Phe could be added to the fourth and fifth positions. Moreover, overexpression of the PG synthesis gene murF further enhanced the levels of d-Met and d-Phe involved in PG and increased the survival rate under acid stress and the nisin yield of the strain. This study reveals that the exogenous supply of d-Met or d-Phe can change the composition of the cell wall and influence acid tolerance as well as nisin yield in L. lactis. IMPORTANCE As d-amino acids play an important role in cell wall synthesis, we analyzed the effects of 19 different d-amino acids on L. lactis F44, demonstrating that d-Met and d-Phe can participate in peptidoglycan (PG) synthesis and improve the acid resistance and nisin yield of this strain. murF overexpression further increased the levels of d-Met and d-Phe incorporated into PG and contributed to the acid resistance of the strain. These findings suggest that d-Met and d-Phe can be incorporated into PG to improve the acid resistance and nisin yield of L. lactis, and this study provides new ideas for the enhancement of nisin production.

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