scholarly journals Identification of novel small molecule inhibitors of 4-diphosphocytidyl-2-C-methyl-d-erythritol (CDP-ME) kinase of Gram-negative bacteria

2011 ◽  
Vol 19 (19) ◽  
pp. 5886-5895 ◽  
Author(s):  
M. Tang ◽  
S.I. Odejinmi ◽  
Y.M. Allette ◽  
H. Vankayalapati ◽  
K. Lai
Keyword(s):  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals A small-molecule inhibitor of BamA impervious to efflux and the outer membrane permeability barrier

2019 ◽  
Vol 116 (43) ◽  
pp. 21748-21757 ◽  
Author(s):  
Elizabeth M. Hart ◽  
Angela M. Mitchell ◽  
Anna Konovalova ◽  
Marcin Grabowicz ◽  
Jessica Sheng ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Small Molecule ◽  
Cytoplasmic Membrane ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Bam Complex ◽  
Induced Aggregation

The development of new antimicrobial drugs is a priority to combat the increasing spread of multidrug-resistant bacteria. This development is especially problematic in gram-negative bacteria due to the outer membrane (OM) permeability barrier and multidrug efflux pumps. Therefore, we screened for compounds that target essential, nonredundant, surface-exposed processes in gram-negative bacteria. We identified a compound, MRL-494, that inhibits assembly of OM proteins (OMPs) by the β-barrel assembly machine (BAM complex). The BAM complex contains one essential surface-exposed protein, BamA. We constructed a bamA mutagenesis library, screened for resistance to MRL-494, and identified the mutation bamAE470K. BamAE470K restores OMP biogenesis in the presence of MRL-494. The mutant protein has both altered conformation and activity, suggesting it could either inhibit MRL-494 binding or allow BamA to function in the presence of MRL-494. By cellular thermal shift assay (CETSA), we determined that MRL-494 stabilizes BamA and BamAE470K from thermally induced aggregation, indicating direct or proximal binding to both BamA and BamAE470K. Thus, it is the altered activity of BamAE470K responsible for resistance to MRL-494. Strikingly, MRL-494 possesses a second mechanism of action that kills gram-positive organisms. In microbes lacking an OM, MRL-494 lethally disrupts the cytoplasmic membrane. We suggest that the compound cannot disrupt the cytoplasmic membrane of gram-negative bacteria because it cannot penetrate the OM. Instead, MRL-494 inhibits OMP biogenesis from outside the OM by targeting BamA. The identification of a small molecule that inhibits OMP biogenesis at the cell surface represents a distinct class of antibacterial agents.

scholarly journals Mechanistic aspects of maltotriose-conjugate translocation to the Gram-negative bacteria cytoplasm

2018 ◽  
Vol 2 (1) ◽  
pp. e201800242 ◽  
Author(s):  
Estelle Dumont ◽  
Julia Vergalli ◽  
Jelena Pajovic ◽  
Satya P Bhamidimarri ◽  
Koldo Morante ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Small Molecule ◽  
Single Channel ◽  
Efflux Pumps ◽  
Gram Negative Bacteria ◽  
Periplasmic Space ◽  
Gram Negative ◽  
Entry Pathway ◽  
Pass Through ◽  
Novel Antibiotics

Small molecule accumulation in Gram-negative bacteria is a key challenge to discover novel antibiotics, because of their two membranes and efflux pumps expelling toxic molecules. An approach to overcome this challenge is to hijack uptake pathways so that bacterial transporters shuttle the antibiotic to the cytoplasm. Here, we have characterized maltodextrin–fluorophore conjugates that can pass through both the outer and inner membranes mediated by components of theEscherichia colimaltose regulon. Single-channel electrophysiology recording demonstrated that the compounds permeate across the LamB channel leading to accumulation in the periplasm. We have also demonstrated that a maltotriose conjugate distributes into both the periplasm and cytoplasm. In the cytoplasm, the molecule activates the maltose regulon and triggers the expression of maltose binding protein in the periplasmic space indicating that the complete maltose entry pathway is induced. This maltotriose conjugate can (i) reach the periplasmic and cytoplasmic compartments to significant internal concentrations and (ii) auto-induce its own entry pathwayviathe activation of the maltose regulon, representing an interesting prototype to deliver molecules to the cytoplasm of Gram-negative bacteria.

The Development of New Small-Molecule Inhibitors Targeting Bacterial Metallo-β-lactamases

2018 ◽  
Vol 18 (10) ◽  
pp. 834-843 ◽  
Author(s):  
Ping Wang ◽  
Jing Cheng ◽  
Cong-Cong Liu ◽  
Kai Tang ◽  
Feng Xu ◽  
...  
Keyword(s):  
Small Molecule ◽  
Horizontal Transfer ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Major Threat ◽  
Extensively Drug Resistant ◽  
Genes Encoding ◽  
Recent Developments ◽  
Almost All

Metallo-β-lactamases (MBLs) are a family of Zn(II)-dependent enzymes that can hydrolyze almost all β-lactam antibiotics. Horizontal transfer of the genes encoding MBLs among Gram-negative bacteria pathogens has led to the emergence of extensively drug-resistant pathogens, which now represent a major threat to human health. As there is not to date yet a clinically available MBL inhibitor, the discovery of new MBL inhibitors has great urgency. This review highlights the recent developments in the discovery of small-molecule MBL inhibitors.

scholarly journals A small molecule that mitigates bacterial infection disrupts Gram-negative cell membranes and is inhibited by cholesterol and neutral lipids

2020 ◽  
Vol 16 (12) ◽  
pp. e1009119
Author(s):  
Jamie L. Dombach ◽  
Joaquin L. J. Quintana ◽  
Toni A. Nagy ◽  
Chun Wan ◽  
Amy L. Crooks ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Cell Membrane ◽  
Mammalian Cell ◽  
Small Molecule ◽  
Cell Membranes ◽  
Neutral Lipids ◽  
Intraperitoneal Administration ◽  
Membrane Integrity ◽  
Gram Negative Bacteria ◽  
Gram Negative

Infections caused by Gram-negative bacteria are difficult to fight because these pathogens exclude or expel many clinical antibiotics and host defense molecules. However, mammals have evolved a substantial immune arsenal that weakens pathogen defenses, suggesting the feasibility of developing therapies that work in concert with innate immunity to kill Gram-negative bacteria. Using chemical genetics, we recently identified a small molecule, JD1, that kills Salmonella enterica serovar Typhimurium (S. Typhimurium) residing within macrophages. JD1 is not antibacterial in standard microbiological media, but rapidly inhibits growth and curtails bacterial survival under broth conditions that compromise the outer membrane or reduce efflux pump activity. Using a combination of cellular indicators and super resolution microscopy, we found that JD1 damaged bacterial cytoplasmic membranes by increasing fluidity, disrupting barrier function, and causing the formation of membrane distortions. We quantified macrophage cell membrane integrity and mitochondrial membrane potential and found that disruption of eukaryotic cell membranes required approximately 30-fold more JD1 than was needed to kill bacteria in macrophages. Moreover, JD1 preferentially damaged liposomes with compositions similar to E. coli inner membranes versus mammalian cell membranes. Cholesterol, a component of mammalian cell membranes, was protective in the presence of neutral lipids. In mice, intraperitoneal administration of JD1 reduced tissue colonization by S. Typhimurium. These observations indicate that during infection, JD1 gains access to and disrupts the cytoplasmic membrane of Gram-negative bacteria, and that neutral lipids and cholesterol protect mammalian membranes from JD1-mediated damage. Thus, it may be possible to develop therapeutics that exploit host innate immunity to gain access to Gram-negative bacteria and then preferentially damage the bacterial cell membrane over host membranes.

Applications of small molecule activators and inhibitors of quorum sensing in Gram-negative bacteria

2012 ◽  
Vol 20 (9) ◽  
pp. 449-458 ◽  
Author(s):  
Warren R.J.D. Galloway ◽  
James T. Hodgkinson ◽  
Steven Bowden ◽  
Martin Welch ◽  
David R. Spring
Keyword(s):  
Quorum Sensing ◽  
Small Molecule ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals Preserving Vascular Integrity Protects Mice Against Multidrug-Resistant Gram-Negative Bacterial Infection

2020 ◽  
Author(s):  
Teclegiorgis Gebremariam ◽  
Lina Zhang ◽  
Sondus Alkhazraji ◽  
Yiyou Gu ◽  
Eman G. Youssef ◽  
...  
Keyword(s):  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Multidrug Resistant ◽  
Small Gtpase ◽  
World Health ◽  
Adjunctive Treatment ◽  
Emerging Pathogens ◽  
Vascular Integrity ◽  
Gram Negative ◽  
Pharmacological Inhibition

ABSTRACTThe rise in multidrug resistant (MDR) organisms portends a serious global threat to the healthcare system with nearly untreatable infectious diseases, including pneumonia and its often fatal sequelae, acute respiratory distress syndrome (ARDS) and sepsis. Gram-negative bacteria (GNB) including Acinetobacter baumannii, Pseudomonas aeruginosa, and carbapenemase-producing Klebsiella pneumoniae (CPKP), are among the World Health Organization and National Institutes of Health’s high priority MDR pathogens for targeted development of new therapies. Here we show that stabilizing the host’s vasculature by genetic deletion or pharmacological inhibition of the small GTPase ADP-ribosylation factor 6 (ARF6) increases survival rates of mice infected with A. baumannii, P. aeruginosa, CPKP pneumonia. We show that pharmacological inhibition of ARF6-GTP phenocopies endothelial-specific Arf6 disruption in enhancing survival of mice with A. baumannii pneumonia, suggesting that inhibition is on target. Finally, we show that the mechanism of protection elicited by these small molecule inhibitors is by restoration of vascular integrity disrupted by GNB lipopolysaccharide (LPS) activation of TLR4/MyD88/ARNO/ARF6 pathway. By targeting the host’s vasculature with small molecule inhibitors of ARF6 activation, we circumvent microbial drug resistance and provide a potential alternative/adjunctive treatment for emerging and re-emerging pathogens.

scholarly journals Porins and small-molecule translocation across the outer membrane of Gram-negative bacteria

2019 ◽  
Vol 18 (3) ◽  
pp. 164-176 ◽  
Author(s):  
Julia Vergalli ◽  
Igor V. Bodrenko ◽  
Muriel Masi ◽  
Lucile Moynié ◽  
Silvia Acosta-Gutiérrez ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Small Molecule ◽  
Gram Negative Bacteria ◽  
Gram Negative

Quorum Sensing in Gram-Negative Bacteria: Small-Molecule Modulation of AHL and AI-2 Quorum Sensing Pathways

2011 ◽  
Vol 111 (1) ◽  
pp. 28-67 ◽  
Author(s):  
Warren R. J. D. Galloway ◽  
James T. Hodgkinson ◽  
Steven D. Bowden ◽  
Martin Welch ◽  
David R. Spring
Keyword(s):  
Quorum Sensing ◽  
Small Molecule ◽  
Gram Negative Bacteria ◽  
Gram Negative

Composites of Bacterial Cellulose and Small Molecule-Decorated Gold Nanoparticles for Treating Gram-Negative Bacteria-Infected Wounds

Small ◽  
2017 ◽  
Vol 13 (27) ◽  
pp. 1700130 ◽  
Author(s):  
Ying Li ◽  
Yue Tian ◽  
Wenshu Zheng ◽  
Yan Feng ◽  
Rong Huang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Cellulose ◽  
Small Molecule ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Infected Wounds

Characterizing and Overcoming Resistance to Aminomethylspectinomycins in Gram-negative Bacteria

2021 ◽  
Author(s):  
◽  
Nisha Das ◽  
Keyword(s):  
Small Molecule ◽  
Legionella Pneumophila ◽  
Bacterial Infections ◽  
Enzyme Assay ◽  
Bacterial Species ◽  
Enteric Bacteria ◽  
Response Analysis ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli

Spectinomycin (SPC) is a broad-spectrum aminocyclitol antibiotic. Its use in agriculture has led to widespread resistance in enteric bacteria, necessitating the development of more effective analogs. Aminomethyl spectinomycins (amSPC) are modified spectinomycins with increased potency against many bacterial species. These species include Legionella pneumophila, which harbors a chromosomally encoded aminoglycoside modifying enzyme (AME). In this study, we follow up on this observation and examine the extent to which the amSPCs are substrates for AMEs through adenylation (ANTs) and phosphorylation (APH). APH(9)-Ia and ANT(3")(9) were expressed in E. coli BL21(DE3) and purified using the Ni-affinity chromatography. The ability of AMEs to modify and inactivate amSPCs has been examined by two unique biochemical assays, including an agar-based enzyme assay. Binding of APH (9)-Ia and ANT (3")(9) to spectinomycin and amSPCs has been studied using Thermal Denaturation assay and MicroScale Thermophoresis (MST). The microbiological role of these enzymes has been examined by minimum inhibitory concentration (MIC) shifts using an arabinose inducible expression of APH (9)-Ia and ANT (3")(9) in E.coli K12 and JW ΔtolC strains. Our agar-based enzyme assay shows the inactivation of spectinomycin by APH(9)-Ia. Phosphorylated spectinomycin and adenylated spectinomycin products upon incubation with APH(9)-Ia and ANT(3",9), respectively, have been identified using MALDI-MS. APH(9)-Ia induction studies in E. coli tolC knock-out strains reveal a MIC increase against spectinomycin in the presence of 2% arabinose compared to no shift with amSPCs. ANT (3")(9) showed an increase in MIC against spectinomycin as well as amSPCs. In conclusion, amSPCs are not inactivated by APH (9)-Ia in vivo but are inactivated by ANT (3")(9). Most Gram-negative bacteria isolated in clinics possess one or more AMEs. By overcoming modification by AMEs, amSPCs can be a valuable tool in overcoming resistance in Gram-negative bacterial infections. We also conducted a high throughput screen of a polar small molecule library against two multi-drug resistant clinical isolates of Escherichia coli that encode aminoglycoside modifying enzyme for small molecule potentiators of amSPCs to yield 12 possible potentiating molecules that have been confirmed by dose-response analysis. Future work as a continuation of this project will involve further analysis of any existing synergy between the potentiating molecules and amSPCs and target validation of these potentiators.

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