101
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López Y, Tato M, Gargallo-Viola D, Cantón R, Vila J, Zsolt I. Mutant prevention concentration of ozenoxacin for quinolone-susceptible or -resistant Staphylococcus aureus and Staphylococcus epidermidis. PLoS One 2019; 14:e0223326. [PMID: 31596898 PMCID: PMC6785070 DOI: 10.1371/journal.pone.0223326] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/18/2019] [Indexed: 11/17/2022] Open
Abstract
Ozenoxacin (OZN) belongs to a new generation of non-fluorinated quinolones for the topical treatment of skin infections which has shown to be effective in the treatment of susceptible and resistant Gram-positive cocci. The mutant prevention concentration (MPC) of ozenoxacin, levofloxacin and ciprofloxacin was determined in quinolone-susceptible and -resistant strains including methicillin-susceptible S. aureus, methicillin-resistant S. aureus, methicillin-susceptible S. epidermidis and methicillin-resistant S. epidermidis with different profile of mutation in the quinolone resistance determining regions (QRDR). The MPC value of OZN for the methicillin-susceptible S. aureus strain susceptible to quinolones, without mutations in QRDR, was 0.05 mg/L, being 280-fold lower than that observed with ciprofloxacin and levofloxacin. In methicillin-susceptible and–resistant S. aureus strains with mutations in the gyrA or/and grlA genes the MPC of OZN went from 0.1 to 6 mg/L, whereas the MPC of levofloxacin and ciprofloxacin was > 50 mg/L for the same strains. For methicillin-susceptible and–resistant S. epidermidis the results were similar to those abovementioned for S. aureus. According to our results, the MPC of OZN was far below the quantity of ozenoxacin achieved in the epidermal layer, suggesting that the in vivo selection of mutants, if it occurs, will take place at low frequency. Ozenoxacin is an excellent candidate for the treatment of bacterial infections caused by susceptible and quinolone-resistant staphylococci isolated usually from skin infections.
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Affiliation(s)
- Y López
- Institute of Global Health of Barcelona, Barcelona, Spain
| | - M Tato
- Department of Clinical Microbiology, Hospital Universitario Ramón y Cajal & Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | | | - R Cantón
- Department of Clinical Microbiology, Hospital Universitario Ramón y Cajal & Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - J Vila
- Institute of Global Health of Barcelona, Barcelona, Spain.,Department of Clinical Microbiology, Hospital Clinic, School of Medicine, University of Barcelona, Spain
| | - I Zsolt
- Medical Department, Ferrer Internacional, Barcelona, Spain
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102
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Cabral DJ, Penumutchu S, Reinhart EM, Zhang C, Korry BJ, Wurster JI, Nilson R, Guang A, Sano WH, Rowan-Nash AD, Li H, Belenky P. Microbial Metabolism Modulates Antibiotic Susceptibility within the Murine Gut Microbiome. Cell Metab 2019; 30:800-823.e7. [PMID: 31523007 PMCID: PMC6948150 DOI: 10.1016/j.cmet.2019.08.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/24/2019] [Accepted: 08/20/2019] [Indexed: 12/22/2022]
Abstract
Although antibiotics disturb the structure of the gut microbiota, factors that modulate these perturbations are poorly understood. Bacterial metabolism is an important regulator of susceptibility in vitro and likely plays a large role within the host. We applied a metagenomic and metatranscriptomic approach to link antibiotic-induced taxonomic and transcriptional responses within the murine microbiome. We found that antibiotics significantly alter the expression of key metabolic pathways at the whole-community and single-species levels. Notably, Bacteroides thetaiotaomicron, which blooms in response to amoxicillin, upregulated polysaccharide utilization. In vitro, we found that the sensitivity of this bacterium to amoxicillin was elevated by glucose and reduced by polysaccharides. Accordingly, we observed that dietary composition affected the abundance and expansion of B. thetaiotaomicron, as well as the extent of microbiome disruption with amoxicillin. Our work indicates that the metabolic environment of the microbiome plays a role in the response of this community to antibiotics.
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Affiliation(s)
- Damien J Cabral
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Swathi Penumutchu
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Elizabeth M Reinhart
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Cheng Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55904, USA
| | - Benjamin J Korry
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Jenna I Wurster
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Rachael Nilson
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - August Guang
- Center for Computation & Visualization, Brown University, Brown University, Providence, RI 02906, USA; Center for Computational Biology of Human Disease, Brown University, Providence, RI 02906, USA
| | - William H Sano
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Aislinn D Rowan-Nash
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55904, USA
| | - Peter Belenky
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA.
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103
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Gene networks that compensate for crosstalk with crosstalk. Nat Commun 2019; 10:4028. [PMID: 31492904 PMCID: PMC6731275 DOI: 10.1038/s41467-019-12021-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 08/12/2019] [Indexed: 12/18/2022] Open
Abstract
Crosstalk is a major challenge to engineering sophisticated synthetic gene networks. A common approach is to insulate signal-transduction pathways by minimizing molecular-level crosstalk between endogenous and synthetic genetic components, but this strategy can be difficult to apply in the context of complex, natural gene networks and unknown interactions. Here, we show that synthetic gene networks can be engineered to compensate for crosstalk by integrating pathway signals, rather than by pathway insulation. We demonstrate this principle using reactive oxygen species (ROS)-responsive gene circuits in Escherichia coli that exhibit concentration-dependent crosstalk with non-cognate ROS. We quantitatively map the degree of crosstalk and design gene circuits that introduce compensatory crosstalk at the gene network level. The resulting gene network exhibits reduced crosstalk in the sensing of the two different ROS. Our results suggest that simple network motifs that compensate for pathway crosstalk can be used by biological networks to accurately interpret environmental signals. Crosstalk between genetic circuits is a major challenge for engineering sophisticated networks. Here the authors design networks that compensate for crosstalk by integrating, not insulating, pathways.
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104
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Stokes JM, Lopatkin AJ, Lobritz MA, Collins JJ. Bacterial Metabolism and Antibiotic Efficacy. Cell Metab 2019; 30:251-259. [PMID: 31279676 PMCID: PMC6990394 DOI: 10.1016/j.cmet.2019.06.009] [Citation(s) in RCA: 289] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023]
Abstract
Antibiotics target energy-consuming processes. As such, perturbations to bacterial metabolic homeostasis are significant consequences of treatment. Here, we describe three postulates that collectively define antibiotic efficacy in the context of bacterial metabolism: (1) antibiotics alter the metabolic state of bacteria, which contributes to the resulting death or stasis; (2) the metabolic state of bacteria influences their susceptibility to antibiotics; and (3) antibiotic efficacy can be enhanced by altering the metabolic state of bacteria. Altogether, we aim to emphasize the close relationship between bacterial metabolism and antibiotic efficacy as well as propose areas of exploration to develop novel antibiotics that optimally exploit bacterial metabolic networks.
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Affiliation(s)
- Jonathan M Stokes
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Infectious Disease & Microbiome Program, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA; Machine Learning for Pharmaceutical Discovery and Synthesis Consortium, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Allison J Lopatkin
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Infectious Disease & Microbiome Program, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Michael A Lobritz
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, 4070 Basel, Switzerland
| | - James J Collins
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Infectious Disease & Microbiome Program, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA; Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA.
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105
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Reactive Oxygen Species Production Is a Major Factor Directing the Postantibiotic Effect of Fluoroquinolones in Streptococcus pneumoniae. Antimicrob Agents Chemother 2019; 63:AAC.00737-19. [PMID: 31160286 DOI: 10.1128/aac.00737-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/26/2019] [Indexed: 11/20/2022] Open
Abstract
We studied the molecular mechanisms involved in the postantibiotic effect of the fluoroquinolones levofloxacin and moxifloxacin in Streptococcus pneumoniae Wild-type strain R6 had postantibiotic effects of 2.05 ± 0.10 h (mean ± standard deviation [SD]) and 3.23 ± 0.45 h at 2.5× and 10× MIC of levofloxacin, respectively. Moxifloxacin exhibited lower effects of 0.87 ± 0.1 and 2.41 ± 0.29 h at 2.5× and 10× MIC, respectively. Fluoroquinolone-induced chromosome fragmentation was measured at equivalent postantibiotic effects for levofloxacin (2.5× MIC) and moxifloxacin (10× MIC). After 2 h of drug removal, reductions were approximately 7-fold for levofloxacin and 3-fold for moxifloxacin, without further decreases at later times. Variations in reactive oxygen species production were detected after 4 to 6 h of drug withdrawals, with decreases ≥400-fold for levofloxacin and ≥800-fold for moxifloxacin at 6 h. In accordance, after 4 to 6 h of drug withdrawal, the levofloxacin-induced upregulation of the fatCDEB operon, introducing iron in the bacteria, decreased up to 2- to 3-fold, and the moxifloxacin-induced upregulation of several genes involved in the production of pyruvate was reduced 3- to 7-fold. In accordance, lower postantibiotic effects (up to 1 h) were observed in strain R6 ΔspxB, lacking the main enzyme involved in oxygen peroxide production, than in R6. Although no change in the recovery of chromosome fragmentation was observed between R6 and R6 ΔspxB, 3.5 × 103-fold lower reactive oxygen species production was observed in R6 ΔspxB, without changes after drug removal. These results show that reactive oxygen species are the main factors directing the postantibiotic effect of levofloxacin and moxifloxacin in S. pneumoniae.
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106
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Ctt1 catalase activity potentiates antifungal azoles in the emerging opportunistic pathogen Saccharomyces cerevisiae. Sci Rep 2019; 9:9185. [PMID: 31235707 PMCID: PMC6591360 DOI: 10.1038/s41598-019-45070-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022] Open
Abstract
Fungi respond to antifungal drugs by increasing their antioxidant stress response. How this impacts antifungal efficacy remains controversial and not well understood. Here we examine the role of catalase activity in the resistance of Saccharomyces cerevisiae to the common antifungals, fluconazole and miconazole, for which we report minimum inhibitory concentrations (MICs) of 104 and 19 μM, respectively. At sub-MIC concentrations, fluconazole and miconazole stimulate catalase activity 2-3-fold but, unexpectedly, deletion of cytosolic catalase (ctt1) makes cells more resistant to these azoles and to clotrimazole, itraconazole and posaconazole. On the other hand, upregulating Ctt1 activity by preconditioning with 0.2 mM H2O2 potentiates miconazole 32-fold and fluconazole 4-fold. Since H2O2 preconditioning does not alter the resistance of ctt1Δ cells, which possess negligible catalase activity, we link azole potentiation with Ctt1 upregulation. In contrast, sod2Δ cells deleted for mitochondrial superoxide dismutase are 4–8-fold more azole sensitive than wild-type cells, revealing that Sod2 activity protects cells against azole toxicity. In fact, the ctt1Δ mutant has double the Sod2 activity of wild-type cells so ctt1 deletion increases azole resistance in part by Sod2 upregulation. Notably, deletion of peroxisomal/mitochondrial cta1 or cytosolic sod1 does not alter fluconazole or miconazole potency.
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107
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Babele PK, Kumar J, Chaturvedi V. Proteomic De-Regulation in Cyanobacteria in Response to Abiotic Stresses. Front Microbiol 2019; 10:1315. [PMID: 31263458 PMCID: PMC6584798 DOI: 10.3389/fmicb.2019.01315] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 05/27/2019] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are oxygenic photoautotrophs, exhibiting a cosmopolitan distribution in almost all possible environments and are significantly responsible for half of the global net primary productivity. They are well adapted to the diverse environments including harsh conditions by evolving a range of fascinating repertoires of unique biomolecules and secondary metabolites to support their growth and survival. These phototrophs are proved as excellent models for unraveling the mysteries of basic biochemical and physiological processes taking place in higher plants. Several known species of cyanobacteria have tremendous biotechnological applications in diverse fields such as biofuels, biopolymers, secondary metabolites and much more. Due to their potential biotechnological and commercial applications in various fields, there is an imperative need to engineer robust cyanobacteria in such a way that they can tolerate and acclimatize to ever-changing environmental conditions. Adaptations to stress are mainly governed by a precise gene regulation pathways resulting in the expression of novel protein/enzymes and metabolites. Despite the demand, till date few proteins/enzymes have been identified which play a potential role in improving tolerance against abiotic stresses. Therefore, it is utmost important to study environmental stress responses related to post-genomic investigations, including proteomic changes employing advanced proteomics, synthetic and structural biology workflows. In this respect, the study of stress proteomics offers exclusive advantages to scientists working on these aspects. Advancements on these fields could be helpful in dissecting, characterization and manipulation of physiological and metabolic systems of cyanobacteria to understand the stress induced proteomic responses. Till date, it remains ambiguous how cyanobacteria perceive changes in the ambient environment that lead to the stress-induced proteins thus metabolic deregulation. This review briefly describes the current major findings in the fields of proteome research on the cyanobacteria under various abiotic stresses. These findings may improve and advance the information on the role of different class of proteins associated with the mechanism(s) of stress mitigation in cyanobacteria under harsh environmental conditions.
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Affiliation(s)
- Piyoosh Kumar Babele
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Jay Kumar
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Venkatesh Chaturvedi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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108
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Abstract
Chronic kidney disease (CKD) is a major cause of morbidity and premature mortality and represents a significant global public health issue. Underlying this burden are the many complications of CKD, including mineral and bone disorders, anemia, and accelerated cardiovascular disease. Hyperphosphatemia and elevated levels of fibroblast growth factor 23 (FGF23) have been identified as key independent risk factors for the adverse cardiovascular outcomes that frequently occur in patients with CKD. Auryxia® (ferric citrate; Keryx Biopharmaceuticals, Inc., Boston, MA, USA) is an iron-based compound with distinctive chemical characteristics and a mechanism of action that render it dually effective as a therapy in patients with CKD; it has been approved as a phosphate binder for the control of serum phosphate levels in adult CKD patients treated with dialysis and as an iron replacement product for the treatment of iron deficiency anemia in adult CKD patients not treated with dialysis. This review focuses on Auryxia, its mechanism of action, and the clinical attributes that differentiate it from other, non-pharmaceutical-grade, commercially available forms of ferric citrate and from other commonly used phosphate binder and iron supplement therapies for patients with CKD. Consistent with the chemistry and mechanism of action of Auryxia, multiple clinical studies have demonstrated its efficacy in both lowering serum phosphate levels and improving iron parameters in patients with CKD. Levels of FGF23 decrease significantly with Auryxia treatment, but the effects associated with the cardiovascular system remain to be evaluated in longer-term studies.
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Affiliation(s)
- Tomas Ganz
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
- CHS 47-200J, Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Ave., Los Angeles, CA, 90095, USA.
- CHS 47-200J, Department of Pathology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Ave., Los Angeles, CA, 90095, USA.
| | - Avi Bino
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Isidro B Salusky
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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109
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Nair RR, Sharan D, Sebastian J, Swaminath S, Ajitkumar P. Heterogeneity of ROS levels in antibiotic-exposed mycobacterial subpopulations confers differential susceptibility. MICROBIOLOGY-SGM 2019; 165:668-682. [PMID: 31091187 DOI: 10.1099/mic.0.000797] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phenotypically heterogeneous but genetically identical mycobacterial subpopulations exist in in vitro cultures, in vitro-infected macrophages, infected animal models and tuberculosis patients. In this regard, we recently reported the presence of two subpopulations of cells, which are phenotypically different in length and buoyant density, in mycobacterial cultures. These are the low-buoyant-density short-sized cells (SCs), which constitute ~10-20 % of the population, and the high-buoyant-density normal/long-sized cells (NCs), which form ~80-90 % of the population. The SCs were found to be significantly more susceptible to rifampicin (RIF), isoniazid (INH), H2O2 and acidified nitrite than the NCs. Here we report that the RIF-/INH-/H2O2-exposed SCs showed significantly higher levels of oxidative stress and therefore higher susceptibility than the equivalent number of exposed NCs. Significantly higher levels of hydroxyl radical and superoxide were found in the antibiotic-exposed SCs than in the equivalently exposed NCs. Different proportions of the subpopulation of SCs were found to have different levels of reactive oxygen species (ROS). The hydroxyl radical quencher, thiourea, and the superoxide dismutase mimic, TEMPOL, significantly reduced hydroxyl radical and superoxide levels, respectively, in the antibiotic-exposed SCs and NCs and thereby decreased their differential susceptibility to antibiotics. Thus, the present study shows that the heterogeneity of the reactive oxygen species (ROS) levels in these mycobacterial subpopulations confers differential susceptibility to antibiotics. We have discussed the possible mechanisms that can generate differential ROS levels in the antibiotic-exposed SCs and NCs. The present study advances our current understanding of the molecular mechanisms underlying antibiotic tolerance in mycobacteria.
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Affiliation(s)
- Rashmi Ravindran Nair
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Deepti Sharan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Jees Sebastian
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Sharmada Swaminath
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Parthasarathi Ajitkumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
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110
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Punchi Hewage AND, Yao H, Nammalwar B, Gnanasekaran KK, Lovell S, Bunce RA, Eshelman K, Phaniraj SM, Lee MM, Peterson BR, Battaile KP, Reitz AB, Rivera M. Small Molecule Inhibitors of the BfrB-Bfd Interaction Decrease Pseudomonas aeruginosa Fitness and Potentiate Fluoroquinolone Activity. J Am Chem Soc 2019; 141:8171-8184. [PMID: 31038945 PMCID: PMC6535718 DOI: 10.1021/jacs.9b00394] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
The iron storage
protein bacterioferritin (BfrB) is central to
bacterial iron homeostasis. The mobilization of iron from BfrB, which
requires binding by a cognate ferredoxin (Bfd), is essential to the
regulation of cytosolic iron levels in P. aeruginosa. This paper describes the structure-guided development of small
molecule inhibitors of the BfrB–Bfd protein–protein
interaction. The process was initiated by screening a fragment library
and followed by obtaining the structure of a fragment hit bound to
BfrB. The structural insights were used to develop a series of 4-(benzylamino)-
and 4-((3-phenylpropyl)amino)-isoindoline-1,3-dione analogs that selectively
bind BfrB at the Bfd binding site. Challenging P. aeruginosa cells with the 4-substituted isoindoline analogs revealed a dose-dependent
growth phenotype. Further investigation determined that the analogs
elicit a pyoverdin hyperproduction phenotype that is consistent with
blockade of the BfrB–Bfd interaction and ensuing irreversible
accumulation of iron in BfrB, with concomitant depletion of iron in
the cytosol. The irreversible accumulation of iron in BfrB prompted
by the 4-substituted isoindoline analogs was confirmed by visualization
of BfrB-iron in P. aeruginosa cell lysates separated
on native PAGE gels and stained for iron with Ferene S. Challenging P. aeruginosa cultures with a combination of commercial
fluoroquinolone and our isoindoline analogs results in significantly
lower cell survival relative to treatment with either antibiotic or
analog alone. Collectively, these findings furnish proof of concept
for the usefulness of small molecule probes designed to dysregulate
bacterial iron homeostasis by targeting a protein–protein interaction
pivotal for iron storage in the bacterial cell.
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Affiliation(s)
- Achala N D Punchi Hewage
- Department of Chemistry , University of Kansas , 2030 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Huili Yao
- Department of Chemistry , Louisiana State University , 229A Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Baskar Nammalwar
- Department of Chemistry , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | | | - Scott Lovell
- Protein Structure Laboratory , University of Kansas , 2034 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Richard A Bunce
- Department of Chemistry , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Kate Eshelman
- Department of Chemistry , University of Kansas , 2030 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Sahishna M Phaniraj
- Department of Medicinal Chemistry , University of Kansas , 2034 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Molly M Lee
- Department of Medicinal Chemistry , University of Kansas , 2034 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Blake R Peterson
- Department of Medicinal Chemistry , University of Kansas , 2034 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Kevin P Battaile
- IMCA-CAT , Hauptman Woodward Medical Research Institute , 9700 South Cass Avenue, Building 435A , Argonne , Illinois 60439 , United States
| | - Allen B Reitz
- Fox Chase Chemical Diversity Center, Inc. , 3805 Old Easton Road , Doylestown , Pennsylvania 18902 , United States
| | - Mario Rivera
- Department of Chemistry , Louisiana State University , 229A Choppin Hall , Baton Rouge , Louisiana 70803 , United States
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111
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AmpI Functions as an Iron Exporter To Alleviate β-Lactam-Mediated Reactive Oxygen Species Stress in Stenotrophomonas maltophilia. Antimicrob Agents Chemother 2019; 63:AAC.02467-18. [PMID: 30745379 DOI: 10.1128/aac.02467-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/18/2019] [Indexed: 12/15/2022] Open
Abstract
Stenotrophomonas maltophilia is an organism with a remarkable capacity for drug resistance with several antibiotic resistance determinants in its genome. S. maltophilia genome codes for L1 and L2, responsible for intrinsic β-lactam resistance. The Smlt3721 gene (denoted ampI), located downstream of the L2 gene, encodes an inner membrane protein. The existence of an L2 gene-ampI operon was verified by reverse transcription-PCR (RT-PCR). For aerobically grown S. maltophilia KJ, inactivation of ampI downregulated siderophore synthesis and iron acquisition systems and upregulated the iron storage system, as demonstrated by a transcriptome assay, suggesting that AmpI is involved in iron homeostasis. Compared with the wild-type KJ, an ampI mutant had an elevated intracellular iron level, as revealed by inductively coupled plasma mass spectrometry (ICP-MS) analysis, and increased sensitivity to H2O2, verifying the role of AmpI as an iron exporter. The β-lactam stress increased the intracellular reactive oxygen species (ROS) level and induced the expression of the L1 gene and L2 gene-ampI operon. Compared to its own parental strain, the ampI mutant had reduced growth in β-lactam-containing medium, and the ampI mutant viability was improved after complementation with plasmid pAmpI in either a β-lactamase-positive or β-lactamase-negative genetic background. Collectively, upon challenge with β-lactam, the inducibly expressed L1 and L2 β-lactamases contribute to β-lactam resistance by hydrolyzing β-lactam. AmpI functions as an iron exporter participating in rapidly weakening β-lactam-mediated ROS toxicity. The L1 gene and L2 gene-ampI operon enable S. maltophilia to effectively cope with β-lactam-induced stress.
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112
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Ajiboye TO, Aliyu NO, Ajala-Lawal RA. Lophirones B and C induce oxidative cellular death pathway in Acinetobacter baumannii by inhibiting DNA gyrase. Microb Pathog 2019; 130:226-231. [PMID: 30872146 DOI: 10.1016/j.micpath.2019.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/02/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
Abstract
We evaluated the inactivation of DNA gyrase on the oxidative stress response and sensitivity of A. baumannii to lophirones B and C. The sensitivity of parental and the mutant strains of A. baumannii to lophirones B and C was determined using minimum inhibitory concentration (MIC) and time-kill sensitivity. Inactivation of sodB, katG, recA enhanced the sensitivity of A. baumannii to lophirones B and C. Furthermore, this inactivation increased the accumulation of superoxide anion radical and hydrogen peroxide in lophirones B and C-treated A. baumannii, which was reversed in the presence of thiourea. Inactivation of gyrA stalled lophirones B and C-mediated ROS accumulation in A. baumannii. In addition, lophirones B and C raised the Fe2+ contents of A. baumannii. Dipyridyl (Fe chelator) reversed the sensitivity of A. baumannii to lophirones B and C. Lophirones significantly lowered the NAD+/NADH ratio of A. baumannii. The results of this study revealed that the impact of DNA gyrase in lophirones B and C-mediated ROS accumulation, Fe2+ release and cell death.
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Affiliation(s)
- T O Ajiboye
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria.
| | - N O Aliyu
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria
| | - R A Ajala-Lawal
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria
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113
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Lag Phase Is a Dynamic, Organized, Adaptive, and Evolvable Period That Prepares Bacteria for Cell Division. J Bacteriol 2019; 201:JB.00697-18. [PMID: 30642990 DOI: 10.1128/jb.00697-18] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Lag is a temporary period of nonreplication seen in bacteria that are introduced to new media. Despite latency being described by Müller in 1895, only recently have we gained insights into the cellular processes characterizing lag phase. This review covers literature to date on the transcriptomic, proteomic, metabolomic, physiological, biochemical, and evolutionary features of prokaryotic lag. Though lag is commonly described as a preparative phase that allows bacteria to harvest nutrients and adapt to new environments, the implications of recent studies indicate that a refinement of this view is well deserved. As shown, lag is a dynamic, organized, adaptive, and evolvable process that protects bacteria from threats, promotes reproductive fitness, and is broadly relevant to the study of bacterial evolution, host-pathogen interactions, antibiotic tolerance, environmental biology, molecular microbiology, and food safety.
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114
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Verderosa AD, Dhouib R, Fairfull-Smith KE, Totsika M. Profluorescent Fluoroquinolone-Nitroxides for Investigating Antibiotic⁻Bacterial Interactions. Antibiotics (Basel) 2019; 8:antibiotics8010019. [PMID: 30836686 PMCID: PMC6466543 DOI: 10.3390/antibiotics8010019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 01/13/2023] Open
Abstract
Fluorescent probes are widely used for imaging and measuring dynamic processes in living cells. Fluorescent antibiotics are valuable tools for examining antibiotic⁻bacterial interactions, antimicrobial resistance and elucidating antibiotic modes of action. Profluorescent nitroxides are 'switch on' fluorescent probes used to visualize and monitor intracellular free radical and redox processes in biological systems. Here, we have combined the inherent fluorescent and antimicrobial properties of the fluoroquinolone core structure with the fluorescence suppression capabilities of a nitroxide to produce the first example of a profluorescent fluoroquinolone-nitroxide probe. Fluoroquinolone-nitroxide (FN) 14 exhibited significant suppression of fluorescence (>36-fold), which could be restored via radical trapping (fluoroquinolone-methoxyamine 17) or reduction to the corresponding hydroxylamine 20. Importantly, FN 14 was able to enter both Gram-positive and Gram-negative bacterial cells, emitted a measurable fluorescence signal upon cell entry (switch on), and retained antibacterial activity. In conclusion, profluorescent nitroxide antibiotics offer a new powerful tool for visualizing antibiotic⁻bacterial interactions and researching intracellular chemical processes.
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Affiliation(s)
- Anthony D Verderosa
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4006, Australia.
| | - Rabeb Dhouib
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4006, Australia.
| | - Kathryn E Fairfull-Smith
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
| | - Makrina Totsika
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4006, Australia.
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115
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Kim SY, Park C, Jang HJ, Kim BO, Bae HW, Chung IY, Kim ES, Cho YH. Antibacterial strategies inspired by the oxidative stress and response networks. J Microbiol 2019; 57:203-212. [DOI: 10.1007/s12275-019-8711-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 11/29/2022]
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116
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Briffotaux J, Liu S, Gicquel B. Genome-Wide Transcriptional Responses of Mycobacterium to Antibiotics. Front Microbiol 2019; 10:249. [PMID: 30842759 PMCID: PMC6391361 DOI: 10.3389/fmicb.2019.00249] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/30/2019] [Indexed: 11/13/2022] Open
Abstract
Antibiotics can stimulate or depress gene expression in bacteria. The analysis of transcriptional responses of Mycobacterium to antimycobacterial compounds has improved our understanding of the mode of action of various drug classes and the efficacy and effect of such compounds on the global metabolism of Mycobacterium. This approach can provide new insights for known antibiotics, for example those currently used for tuberculosis treatment, as well as help to identify the mode of action and predict the targets of new compounds identified by whole-cell screening assays. In addition, changes in gene expression profiles after antimycobacterial treatment can provide information about the adaptive ability of bacteria to escape the effects of antibiotics and allow monitoring of the physiology of the bacteria during treatment. Genome-wide expression profiling also makes it possible to pinpoint genes differentially expressed between drug sensitive Mycobacterium and multidrug-resistant clinical isolates. Finally, genes involved in adaptive responses and drug tolerance could become new targets for improving the efficacy of existing antibiotics.
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Affiliation(s)
- Julien Briffotaux
- Department of Tuberculosis Control and Prevention, Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen, China.,Emerging Bacterial Pathogens Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Shengyuan Liu
- Department of Tuberculosis Control and Prevention, Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen, China
| | - Brigitte Gicquel
- Department of Tuberculosis Control and Prevention, Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen, China.,Emerging Bacterial Pathogens Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,Mycobacterial Genetics Unit, Institut Pasteur, Paris, France
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117
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Wang G, Pang J, Hu X, Nie T, Lu X, Li X, Wang X, Lu Y, Yang X, Jiang J, Li C, Xiong YQ, You X. Daphnetin: A Novel Anti- Helicobacter pylori Agent. Int J Mol Sci 2019; 20:ijms20040850. [PMID: 30781382 PMCID: PMC6412720 DOI: 10.3390/ijms20040850] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/02/2019] [Accepted: 02/12/2019] [Indexed: 02/08/2023] Open
Abstract
Background: Antibiotic-resistant H. pylori was increasingly found in infected individuals, which resulted in treatment failure and required alternative therapeutic strategies. Daphnetin, a coumarin-derivative compound, has multiple pharmacological activities. Methods: The mechanism of daphnetin on H. pylori was investigated focusing on its effect on cell morphologies, transcription of genes related to virulence, adhesion, and cytotoxicity to human gastric epithelial (GES-1) cell line. Results: Daphnetin showed good activities against multidrug resistant (MDR) H. pylori clinical isolates, with minimal inhibitory concentration (MIC) values ranging from 25 to 100 μg/mL. In addition, daphnetin exposure resulted in H. pylori morphological changes. Moreover, daphnetin caused increased translocation of phosphatidylserine (PS), DNA damage, and recA expression, and RecA protein production vs. control group. Of great importance, daphnetin significantly decreased H. pylori adhesion to GES-1 cell line vs. control group, which may be related to the reduced expression of colonization related genes (e.g., babA and ureI). Conclusions: These results suggested that daphnetin has good activity against MDR H. pylori. The mechanism(s) of daphnetin against H. pylori were related to change of membrane structure, increase of DNA damage and PS translocation, and decrease of H. pylori attachment to GES-1 cells.
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Affiliation(s)
- Genzhu Wang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jing Pang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xinxin Hu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Tongying Nie
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xi Lu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xue Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xiukun Wang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Yun Lu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xinyi Yang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jiandong Jiang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Congran Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA 90502, USA.
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
| | - Xuefu You
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
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118
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Minasyan H. Sepsis: mechanisms of bacterial injury to the patient. Scand J Trauma Resusc Emerg Med 2019; 27:19. [PMID: 30764843 PMCID: PMC6376788 DOI: 10.1186/s13049-019-0596-4] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/01/2019] [Indexed: 12/17/2022] Open
Abstract
In bacteremia the majority of bacterial species are killed by oxidation on the surface of erythrocytes and digested by local phagocytes in the liver and the spleen. Sepsis-causing bacteria overcome this mechanism of human innate immunity by versatile respiration, production of antioxidant enzymes, hemolysins, exo- and endotoxins, exopolymers and other factors that suppress host defense and provide bacterial survival. Entering the bloodstream in different forms (planktonic, encapsulated, L-form, biofilm fragments), they cause different types of sepsis (fulminant, acute, subacute, chronic, etc.). Sepsis treatment includes antibacterial therapy, support of host vital functions and restore of homeostasis. A bacterium killing is only one of numerous aspects of antibacterial therapy. The latter should inhibit the production of bacterial antioxidant enzymes and hemolysins, neutralize bacterial toxins, modulate bacterial respiration, increase host tolerance to bacterial products, facilitate host bactericidal mechanism and disperse bacterial capsule and biofilm.
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119
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Enhanced NADH Metabolism Involves Colistin-Induced Killing of Bacillus subtilis and Paenibacillus polymyxa. Molecules 2019; 24:molecules24030387. [PMID: 30678237 PMCID: PMC6384706 DOI: 10.3390/molecules24030387] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/08/2019] [Accepted: 01/22/2019] [Indexed: 11/17/2022] Open
Abstract
The commonly believed mechanism of colistin against Gram-negative bacteria is to cause cell membrane lysis, whereas the mechanism of colistin against Gram-positive bacteria is extremely fragmented. In this study, we found that colistin treatment on Bacillus subtilis WB800, Paenibacillus polymyxa C12 and Paenibacillus polymyxa ATCC842 enhances not only the activities of α-ketoglutaric dehydrogenase and malate dehydrogenase in tricarboxylic acid (TCA) cycle, but also the relative expression levels of their encoding genes. Additionally, the oxaloacetate concentration also increases. Interestingly, the analysis of the relative expression of genes specific for respiratory chain showed that colistin treatment stimulates the respiratory chain in Gram-positive bacteria. Accordingly, the NAD+/NADH ratio increases and the oxidative level is then boosted up. As a result, the intensive oxidative damages are induced in Gram-positive bacteria and cells are killed. Notably, both rotenone and oligomycin, respectively, inhibiting NADH dehydrogenase and phosphorylation on respiratory chain can downgrade oxidative stress formation, thus alleviating the colistin-induced killing of Gram-positive cells. Besides, thiourea-based scavenging for reactive oxygen species also rescues the colistin-subjected cells. These data collectively demonstrate that colistin stimulates both TCA cycle and respiratory chain in Gram-positive bacteria, leading to the enhancement of NADH metabolism and resulting in the generation of oxidative damages in Gram-positive cells. Our studies provide a better understanding of antibacterial mechanism of colistin against Gram-positive bacteria, which is important for knowledge on bacterial resistance to colistin happening via the inhibition of respiratory chain and manipulation of its production.
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120
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Khodour Y, Kaguni LS, Stiban J. Iron-sulfur clusters in nucleic acid metabolism: Varying roles of ancient cofactors. Enzymes 2019; 45:225-256. [PMID: 31627878 DOI: 10.1016/bs.enz.2019.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite their relative simplicity, iron-sulfur clusters have been omnipresent as cofactors in myriad cellular processes such as oxidative phosphorylation and other respiratory pathways. Recent research advances confirm the presence of different clusters in enzymes involved in nucleic acid metabolism. Iron-sulfur clusters can therefore be considered hallmarks of cellular metabolism. Helicases, nucleases, glycosylases, DNA polymerases and transcription factors, among others, incorporate various types of clusters that serve differing roles. In this chapter, we review our current understanding of the identity and functions of iron-sulfur clusters in DNA and RNA metabolizing enzymes, highlighting their importance as regulators of cellular function.
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Affiliation(s)
- Yara Khodour
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Johnny Stiban
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine.
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121
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Mu C, Prosser KE, Harrypersad S, MacNeil GA, Panchmatia R, Thompson JR, Sinha S, Warren JJ, Walsby CJ. Activation by Oxidation: Ferrocene-Functionalized Ru(II)-Arene Complexes with Anticancer, Antibacterial, and Antioxidant Properties. Inorg Chem 2018; 57:15247-15261. [PMID: 30495936 DOI: 10.1021/acs.inorgchem.8b02542] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Organometallic Ru(II)-cymene complexes linked to ferrocene (Fc) via nitrogen heterocycles have been synthesized and studied as cytotoxic agents. These compounds are analogues of Ru(II)-arene piano-stool anticancer complexes such as RAPTA-C. The Ru center was coordinated by pyridine, imidazole, and piperidine with 0-, 1-, or 2-carbon bridges to Fc to give six bimetallic, dinuclear compounds, and the properties of these complexes were compared with their non-Fc-functionalized parent compounds. Crystal structures for five of the compounds, their Ru-cymene parent compounds, and an unusual trinuclear compound were determined. Cyclic voltammetry was used to determine the formal MIII/II potentials of each metal center of the Ru-cymene-Fc complexes, with distinct one-electron waves observed in each case. The Fc-functionalized complexes were found to exhibit good cytotoxicity against HT29 human colon adenocarcinoma cells, whereas the parent compounds were inactive. Similarly, antibacterial activity from the Ru-cymene-Fc compounds was observed against Bacillus subtilis, but not from the unfunctionalized complexes. In both cases, the IC50 values correlated quantitatively with the Fc+/0 reduction potentials. This is consistent with more facile oxidation to give ferrocenium, and subsequent generation of toxic reactive oxygen species, leading to greater cytotoxicity. The antioxidant properties of the complexes were quantified by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. EC50 values indicate that linking of the Ru and Fc centers promotes antioxidant activity.
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Affiliation(s)
- Changhua Mu
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Kathleen E Prosser
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Shane Harrypersad
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Gregory A MacNeil
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Rikesh Panchmatia
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - John R Thompson
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Soumalya Sinha
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Jeffrey J Warren
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
| | - Charles J Walsby
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby V5A 1S6 , British Columbia , Canada
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122
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Nuti S, Fernández-Lodeiro J, Del Secco B, Rampazzo E, Rodríguez-González B, Capelo JL, Silva V, Igrejas G, Poeta P, Torres C, Zaccheroni N, Prodi L, Oliveira E, Lodeiro C. Engineered Nanostructured Materials for Ofloxacin Delivery. Front Chem 2018; 6:554. [PMID: 30538980 PMCID: PMC6277636 DOI: 10.3389/fchem.2018.00554] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/29/2018] [Indexed: 12/03/2022] Open
Abstract
Antibiotic resistance is emerging as a growing worldwide problem and finding solutions to this issue is becoming a new challenge for scientists. As the development of new drugs slowed down, advances in nanotechnology offer great opportunities, with the possibility of designing new systems for carrying, delivery and administration of drugs already in use. Engineered combinations of the synthetic, broad-spectrum antibiotic ofloxacin, rarely studied in this field, with different types of silver, mesoporous silica-based and Pluronic/silica-based nanoparticles have been explored. The nanocarriers as silver core@silica mesoporous (AgMSNPs) and dye-doped silica nanoparticles functionalized with ofloxacin were synthesized and their antibacterial properties studied against S. aureus and E. coli. The best antibacterial results were obtained for the AgMSNPs nanosystem@ofloxacin for the strain S. aureus ATCC 25923, with MIC and MBC values of 5 and 25 μg/mL, proving the efficacy and synergetic effect of the antibiotic and the Ag core of the nanoparticles.
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Affiliation(s)
- Silvia Nuti
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal
- G. Ciamician Department of Chemistry, University of Bologna, Bologna, Italy
| | - Javier Fernández-Lodeiro
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal
- Proteomass Scientific Society, Costa de Caparica, Portugal
| | | | - Enrico Rampazzo
- G. Ciamician Department of Chemistry, University of Bologna, Bologna, Italy
| | | | - José L. Capelo
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal
- Proteomass Scientific Society, Costa de Caparica, Portugal
| | - Vanessa Silva
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- Veterinary Science Department, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- LAQV-REQUIMTE, Faculty of Science and Technology, Nova University of Lisbon, Lisbon, Portugal
| | - Gilberto Igrejas
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- LAQV-REQUIMTE, Faculty of Science and Technology, Nova University of Lisbon, Lisbon, Portugal
| | - Patrícia Poeta
- Veterinary Science Department, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
- LAQV-REQUIMTE, Faculty of Science and Technology, Nova University of Lisbon, Lisbon, Portugal
| | - Cármen Torres
- Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain
| | - Nelsi Zaccheroni
- G. Ciamician Department of Chemistry, University of Bologna, Bologna, Italy
| | - Luca Prodi
- G. Ciamician Department of Chemistry, University of Bologna, Bologna, Italy
| | - Elisabete Oliveira
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal
- Proteomass Scientific Society, Costa de Caparica, Portugal
| | - Carlos Lodeiro
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal
- Proteomass Scientific Society, Costa de Caparica, Portugal
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123
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Arokiyaraj S, Bharanidharan R, Agastian P, Shin H. Chemical composition, antioxidant activity and antibacterial mechanism of action from Marsilea minuta leaf hexane: methanol extract. Chem Cent J 2018; 12:105. [PMID: 30343444 PMCID: PMC6768035 DOI: 10.1186/s13065-018-0476-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 10/10/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the present study, hexane: methanol (50:50) leaf extract of Marisela minuta has been evaluated for its chemical composition, antioxidant effect and the antimicrobial mechanism of action against food borne pathogenic bacteria. RESULTS The phytochemical evaluation of extract by GC/MS revealed the major abundance of benzoic acid-4-ethoxyethyl ester (43.39%) and farnesol acetate (18.42%). The extract exhibited potential antioxidant and free radical scavenging properties with promising antibacterial activities against the test pathogens with Pseudomonas aeruginosa being the most susceptible with maximum inhibition zone (17 mm) and IC50 value of 125 µg, respectively. The significant (p < 0.05) increase in intracellular super oxide dismutase (SOD), protein leakage, extracellular alkaline phosphatase and lactate dehydrogenase in treated test pathogens suggested an increase in oxidative stress reveling the mechanism of action of phytochemicals. Scanning electron microscopy analysis of treated pathogens also showed swollen and distorted cells. The bioactive molecules in the extract were efficiently docked with virulent enzymes and farnesol acetate showed best energy value of - 5.19 and - 4.27 kcal/mol towards Topoisomerase IV and SHV-2 respectively. Benzoic acid-4-ethoxyethyl ester showed best binding against TEM-72 with low binding energy value of - 4.35 kcal/mol. CONCLUSION Due to its antioxidant and antibacterial properties, the leaf extract of M. minuta may act as promising natural additives to prevent food spoilage bacteria.
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Affiliation(s)
- Selvaraj Arokiyaraj
- Department of Food Science and Biotechnology, College of Life Science, Sejong University, Seoul, 05006, Republic of Korea
| | - Rajaraman Bharanidharan
- Department of International Agricultural Technology, Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang, Gangwon, 25354, Republic of Korea
- Institute of Green Bioscience and Technology, Seoul National University, Pyeongchang, Gangwon, 25354, Republic of Korea
| | - Paul Agastian
- Department of Plant Biology and Biotechnology, Loyola College, Nungambakkam, Chennai, 600034, India
| | - Hakdong Shin
- Department of Food Science and Biotechnology, College of Life Science, Sejong University, Seoul, 05006, Republic of Korea.
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124
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Li J, Ma L, Liao X, Liu D, Lu X, Chen S, Ye X, Ding T. Ultrasound-Induced Escherichia coli O157:H7 Cell Death Exhibits Physical Disruption and Biochemical Apoptosis. Front Microbiol 2018; 9:2486. [PMID: 30459727 PMCID: PMC6232819 DOI: 10.3389/fmicb.2018.02486] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/28/2018] [Indexed: 12/30/2022] Open
Abstract
Ultrasound has attracted great interest of both industry and scientific communities for its potential use as a physical processing and preservation tool. In this study, Escherichia coli O157:H7 was selected as the model microbe to investigate the ultrasound-induced cell death. Slight variations in membrane potential and ion exchanges across membrane induced by low-intensity ultrasound increased the membrane permeability of E. coli O157:H7, and this reversible sublethal effect can preserve the viability of E. coli O157:H7 and meanwhile be beneficial for bioprocessing application. In comparison, high-intensity ultrasound resulted in irreversible lethal effect on E. coli O157:H7, which can be applied in the field of microbial inactivation. In addition, both low- and high-intensity ultrasound induced either physical destruction or trigger genetically encoded apoptosis of E. coli O157:H7. Accumulation of reactive oxygen species and decrease of adenosine tri-phosphate might be related to the physiological and biochemical hallmarks of apoptosis, including exposed phosphatidylserine and activated caspases in E. coli O157:H7. The result provides novel insight into the mechanisms of non-thermal physical treatment on the inactivation of bacteria and lays foundation for the further research on the cell signaling and metabolic pathway in apoptotic bacteria.
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Affiliation(s)
- Jiao Li
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
| | - Luyao Ma
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Xinyu Liao
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
| | - Donghong Liu
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
| | - Xiaonan Lu
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Shiguo Chen
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
| | - Xingqian Ye
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
| | - Tian Ding
- Department of Food Science and Nutrition, National Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou, China.,Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou, China
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125
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Rebollo-Ramirez S, Krokowski S, Lobato-Márquez D, Thomson M, Pennisi I, Mostowy S, Larrouy-Maumus G. Intact Cell Lipidomics Reveal Changes to the Ratio of Cardiolipins to Phosphatidylinositols in Response to Kanamycin in HeLa and Primary Cells. Chem Res Toxicol 2018; 31:688-696. [PMID: 29947513 PMCID: PMC6103485 DOI: 10.1021/acs.chemrestox.8b00038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Indexed: 01/03/2023]
Abstract
Antimicrobial resistance is a major threat the world is currently facing. Development of new antibiotics and the assessment of their toxicity represent important challenges. Current methods for addressing antibiotic toxicity rely on measuring mitochondrial damage using ATP and/or membrane potential as a readout. In this study, we propose an alternative readout looking at changes in the lipidome on intact and unprocessed cells by matrix-assisted laser desorption ionization mass spectrometry. As a proof of principle, we evaluated the impact of known antibiotics (levofloxacin, ethambutol, and kanamycin) on the lipidome of HeLa cells and mouse bone marrow-derived macrophages. Our methodology revealed that clinically relevant concentrations of kanamycin alter the ratio of cardiolipins to phosphatidylinositols. Unexpectedly, only kanamycin had this effect even though all antibiotics used in this study led to a decrease in the maximal mitochondrial respiratory capacity. Altogether, we report that intact cell-targeted lipidomics can be used as a qualitative method to rapidly assess the toxicity of aminoglycosides in HeLa and primary cells. Moreover, these results demonstrate there is no direct correlation between the ratio of cardiolipins to phosphatidylinositols and the maximal mitochondrial respiratory capacity.
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Affiliation(s)
- Sonia Rebollo-Ramirez
- MRC
Centre for Molecular Bacteriology and Infection, Department of Life
Sciences, Faculty of Natural Sciences, Imperial
College London, London SW7 2AZ, U.K.
| | - Sina Krokowski
- MRC
Centre for Molecular Bacteriology and Infection, Department of Medicine,
Section of Microbiology, Imperial College
London, London W12 0NN, U.K.
- Department
of Immunology and Infection, London School
of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K.
| | - Damian Lobato-Márquez
- MRC
Centre for Molecular Bacteriology and Infection, Department of Medicine,
Section of Microbiology, Imperial College
London, London W12 0NN, U.K.
- Department
of Immunology and Infection, London School
of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K.
| | - Michael Thomson
- MRC
Centre for Molecular Bacteriology and Infection, Department of Life
Sciences, Faculty of Natural Sciences, Imperial
College London, London SW7 2AZ, U.K.
| | - Ivana Pennisi
- MRC
Centre for Molecular Bacteriology and Infection, Department of Life
Sciences, Faculty of Natural Sciences, Imperial
College London, London SW7 2AZ, U.K.
| | - Serge Mostowy
- MRC
Centre for Molecular Bacteriology and Infection, Department of Medicine,
Section of Microbiology, Imperial College
London, London W12 0NN, U.K.
- Department
of Immunology and Infection, London School
of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K.
| | - Gerald Larrouy-Maumus
- MRC
Centre for Molecular Bacteriology and Infection, Department of Life
Sciences, Faculty of Natural Sciences, Imperial
College London, London SW7 2AZ, U.K.
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126
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Huang X, Duan X, Li J, Niu J, Yuan S, Wang X, Lambert N, Li X, Xu J, Gong Z, Yan S, Xie L, Xie J. The Synergistic Effect of Exogenous Glutamine and Rifampicin Against Mycobacterium Persisters. Front Microbiol 2018; 9:1625. [PMID: 30079057 PMCID: PMC6062616 DOI: 10.3389/fmicb.2018.01625] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 06/28/2018] [Indexed: 12/22/2022] Open
Abstract
Persisters, stochastic dormant variants of normal bacteria cell, represent a significant portion of the survivors upon exposure to antibiotics and other environmental stresses, which contributes substantially to high level antibiotics tolerance. Glutamine is a crucial component of the Mycobacteria nitrogen pool that is indispensable for survival upon stresses. To study whether a synergistic effect exists between glutamine and antibiotics against Mycobacterial persisters, the efficacy of rifampicin alone or together with exogenous glutamine upon Mycobacterium smegmatis mc2 155 persisters was monitored. The result showed that glutamine decreases M. smegmatis tolerance to rifampicin upon starvation. The reactive oxygen species level of the strains treated with rifampicin and glutamine increased. The synergism of glutamine and rifampicin to kill persisters might derive from altering the oxidative phosphorylation and TCA cycle, as both evidenced by both ATP level increase and transcriptome change. Glutamine might represent a synergistic agent of rifampicin to kill Mycobacteria persisters.
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Affiliation(s)
- Xue Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xiangke Duan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Jiang Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Jingjing Niu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Siqi Yuan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xiaoyu Wang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Nzungize Lambert
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xue Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Junqi Xu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Zhen Gong
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Shuangquan Yan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Longxiang Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
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127
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Robertson J, Gizdavic-Nikolaidis M, Nieuwoudt MK, Swift S. The antimicrobial action of polyaniline involves production of oxidative stress while functionalisation of polyaniline introduces additional mechanisms. PeerJ 2018; 6:e5135. [PMID: 29967756 PMCID: PMC6026458 DOI: 10.7717/peerj.5135] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/08/2018] [Indexed: 12/31/2022] Open
Abstract
Polyaniline (PANI) and functionalised polyanilines (fPANI) are novel antimicrobial agents whose mechanism of action was investigated. Escherichia coli single gene deletion mutants revealed that the antimicrobial mechanism of PANI likely involves production of hydrogen peroxide while homopolymer poly(3-aminobenzoic acid), P3ABA, used as an example of a fPANI, disrupts metabolic and respiratory machinery, by targeting ATP synthase and causes acid stress. PANI was more active against E. coli in aerobic, compared to anaerobic, conditions, while this was apparent for P3ABA only in rich media. Greater activity in aerobic conditions suggests involvement of reactive oxygen species. P3ABA treatment causes an increase in intracellular free iron, which is linked to perturbation of metabolic enzymes and could promote reactive oxygen species production. Addition of exogenous catalase protected E. coli from PANI antimicrobial action; however, this was not apparent for P3ABA treated cells. The results presented suggest that PANI induces production of hydrogen peroxide, which can promote formation of hydroxyl radicals causing biomolecule damage and potentially cell death. P3ABA is thought to act as an uncoupler by targeting ATP synthase resulting in a futile cycle, which precipitates dysregulation of iron homeostasis, oxidative stress, acid stress, and potentially the fatal loss of proton motive force.
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Affiliation(s)
- Julia Robertson
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | | | | | - Simon Swift
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
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128
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Influence of Reactive Oxygen Species on De Novo Acquisition of Resistance to Bactericidal Antibiotics. Antimicrob Agents Chemother 2018; 62:AAC.02354-17. [PMID: 29581120 DOI: 10.1128/aac.02354-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/22/2018] [Indexed: 12/16/2022] Open
Abstract
The radical-based theory proposes that three major classes of bactericidal antibiotics, i.e., β-lactams, quinolones, and aminoglycosides, have in common the downstream formation of lethal levels of reactive oxygen species (ROS) as part of the killing mechanism. If bactericidal antibiotics exhibit a common mechanism, then it is to be expected that the acquisition of resistance against these drugs would have some shared traits as well. Indeed, cells made resistant to one bactericidal antibiotic more rapidly became resistant to another. This effect was absent after induced resistance to a bacteriostatic drug. De novo acquisition of resistance to one bactericidal antibiotic provided partial protection to killing by bactericidal antibiotics from a different class. This protective effect was observed in short-term experiments. No protective effect was detected during 24-h exposures, suggesting that cross-resistance did not occur. In the wild-type strain, exposure to bactericidal antibiotics increased intracellular ROS levels. This increase in ROS levels was not observed when strains resistant to these drugs were exposed to the same concentrations. These results indicate that de novo acquisition of resistance to the bactericidal drugs tested involves a common cellular response that provides protection against ROS accumulation upon exposure to this type of antibiotics. A central mechanism or at least a few common elements within the separate mechanisms possibly play a role during the acquisition of antibiotic resistance.
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129
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Death and population dynamics affect mutation rate estimates and evolvability under stress in bacteria. PLoS Biol 2018; 16:e2005056. [PMID: 29750784 PMCID: PMC5966242 DOI: 10.1371/journal.pbio.2005056] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/23/2018] [Accepted: 04/12/2018] [Indexed: 11/29/2022] Open
Abstract
The stress-induced mutagenesis hypothesis postulates that in response to stress, bacteria increase their genome-wide mutation rate, in turn increasing the chances that a descendant is able to better withstand the stress. This has implications for antibiotic treatment: exposure to subinhibitory doses of antibiotics has been reported to increase bacterial mutation rates and thus probably the rate at which resistance mutations appear and lead to treatment failure. More generally, the hypothesis posits that stress increases evolvability (the ability of a population to generate adaptive genetic diversity) and thus accelerates evolution. Measuring mutation rates under stress, however, is problematic, because existing methods assume there is no death. Yet subinhibitory stress levels may induce a substantial death rate. Death events need to be compensated by extra replication to reach a given population size, thus providing more opportunities to acquire mutations. We show that ignoring death leads to a systematic overestimation of mutation rates under stress. We developed a system based on plasmid segregation that allows us to measure death and division rates simultaneously in bacterial populations. Using this system, we found that a substantial death rate occurs at the tested subinhibitory concentrations previously reported to increase mutation rate. Taking this death rate into account lowers and sometimes removes the signal for stress-induced mutagenesis. Moreover, even when antibiotics increase mutation rate, we show that subinhibitory treatments do not increase genetic diversity and evolvability, again because of effects of the antibiotics on population dynamics. We conclude that antibiotic-induced mutagenesis is overestimated because of death and that understanding evolvability under stress requires accounting for the effects of stress on population dynamics as much as on mutation rate. Our goal here is dual: we show that population dynamics and, in particular, the numbers of cell divisions are crucial but neglected parameters in the evolvability of a population, and we provide experimental and computational tools and methods to study evolvability under stress, leading to a reassessment of the magnitude and significance of the stress-induced mutagenesis paradigm. The effect of environmental stress on bacterial mutagenesis has been a paradigm-shift discovery. Recent developments include evidence that various antibiotics increase mutation rates in bacteria when used at subinhibitory concentrations. It is therefore suggested that such treatments promote resistance evolution because they increase the generation of genetic variation on which natural selection can act. However, existing methods to compute mutation rate neglect the effect of stress on death and population dynamics. Developing new experimental and computational tools, we find that taking death into account significantly lowers the signal for stress-induced mutagenesis. Moreover, we show that treatments that increase mutation rate do not always lead to increased genetic diversity, which questions the standard paradigm of increased evolvability under stress.
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130
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Our Evolving Understanding of the Mechanism of Quinolones. Antibiotics (Basel) 2018; 7:antibiotics7020032. [PMID: 29642475 PMCID: PMC6023003 DOI: 10.3390/antibiotics7020032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/30/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022] Open
Abstract
The maintenance of DNA supercoiling is essential for the proper regulation of a plethora of biological processes. As a consequence of this mode of regulation, ahead of the replication fork, DNA replication machinery is prone to introducing supercoiled regions into the DNA double helix. Resolution of DNA supercoiling is essential to maintain DNA replication rates that are amenable to life. This resolution is handled by evolutionarily conserved enzymes known as topoisomerases. The activity of topoisomerases is essential, and therefore constitutes a prime candidate for targeting by antibiotics. In this review, we present hallmark investigations describing the mode of action of quinolones, one of the antibacterial classes targeting the function of topoisomerases in bacteria. By chronologically analyzing data gathered on the mode of action of this imperative antibiotic class, we highlight the necessity to look beyond primary drug-target interactions towards thoroughly understanding the mechanism of quinolones at the level of the cell.
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131
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Mack SG, Turner RL, Dwyer DJ. Achieving a Predictive Understanding of Antimicrobial Stress Physiology through Systems Biology. Trends Microbiol 2018. [PMID: 29530606 DOI: 10.1016/j.tim.2018.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The dramatic spread and diversity of antibiotic-resistant pathogens has significantly reduced the efficacy of essentially all antibiotic classes, bringing us ever closer to a postantibiotic era. Exacerbating this issue, our understanding of the multiscale physiological impact of antimicrobial challenge on bacterial pathogens remains incomplete. Concerns over resistance and the need for new antibiotics have motivated the collection of omics measurements to provide systems-level insights into antimicrobial stress responses for nearly 20 years. Although technological advances have markedly improved the types and resolution of such measurements, continued development of mathematical frameworks aimed at providing a predictive understanding of complex antimicrobial-associated phenotypes is critical to maximize the utility of multiscale data. Here we highlight recent efforts utilizing systems biology to enhance our knowledge of antimicrobial stress physiology. We provide a brief historical perspective of antibiotic-focused omics measurements, highlight new measurement discoveries and trends, discuss examples and opportunities for integrating measurements with mathematical models, and describe future challenges for the field.
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Affiliation(s)
- Sean G Mack
- Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA
| | - Randi L Turner
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Daniel J Dwyer
- Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA; Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA; Institute for Physical Sciences & Technology, University of Maryland, College Park, MD 20742, USA; Department of Bioengineering, University of Maryland, College Park, MD 20742, USA; Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA.
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132
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Nie T, Zhang C, Huang A, Li P. Epigallocatechin Gallate-Mediated Cell Death Is Triggered by Accumulation of Reactive Oxygen Species Induced via the Cpx Two-Component System in Escherichia coli. Front Microbiol 2018; 9:246. [PMID: 29497416 PMCID: PMC5819313 DOI: 10.3389/fmicb.2018.00246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 01/31/2018] [Indexed: 12/31/2022] Open
Abstract
The high antimicrobial activity of epigallocatechin gallate (EGCG), the most bioactive component of tea polyphenol with a number of health benefits, is well-known. However, little is known about the mechanism involved. Here, we discovered the relationship between reactive oxygen species (ROS), the Cpx system, and EGCG-mediated cell death. We first found an increase in ampicillin resistance as well as the transcription level of a LD-transpeptidase (LD-TPase) involved in cell wall synthesis; ycbB transcription was upregulated whereas that of another LD-TPase, ynhG, appeared to be constant after a short exposure of Escherichia coli to sub-inhibitory doses of EGCG. Additionally, the transcription level of cpxP, a downstream gene belonging to the Cpx regulon, was positively correlated with the concentration of EGCG, and significant upregulation was detected when cells were treated with high doses of EGCG. Through analysis of a cpxR deletion strain (ΔcpxR), we identified a constant ROS level and a notable increase in the survival rate of ΔcpxR, while the ROS level increased and the survival rate decreased remarkably in the wild-type strain. Furthermore, thiourea, which is an antioxidant, reduced the ROS level and antimicrobial activity of EGCG. Taken together, these results suggest that EGCG induces ROS formation by activating the Cpx system and mediates cell death.
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Affiliation(s)
- Tao Nie
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chenlu Zhang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Antian Huang
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China.,Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ping Li
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
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133
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Panda S, Rout TK, Prusty AD, Ajayan PM, Nayak S. Electron Transfer Directed Antibacterial Properties of Graphene Oxide on Metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1702149. [PMID: 29315841 DOI: 10.1002/adma.201702149] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/27/2017] [Indexed: 05/28/2023]
Abstract
Nanomaterials such as silver nanoparticles and graphene-based composites are known to exhibit biocidal activities. However, interactions with surrounding medium or supporting substrates can significantly influence this activity. Here, it is shown that superior antimicrobial properties of natural shellac-derived graphene oxide (GO) coatings is obtained on metallic films, such as Zn, Ni, Sn, and steel. It is also found that such activities are directly correlated to the electrical conductivity of the GO-metal systems; the higher the conductivity the better is the antibacterial activity. GO-metal substrate interactions serve as an efficient electron sink for the bacterial respiratory pathway, where electrons modify oxygen containing functional groups on GO surfaces to generate reactive oxygen species (ROS). A concerted effect of nonoxidative electron transfer mechanism and consequent ROS mediated oxidative stress to the bacteria result in an enhanced antimicrobial action of naturally derived GO-metal films. The lack of germicidal effect in exposed cells for GO supported on electrically nonconductive substrates such as glass corroborates the above hypothesis. The results can lead to new GO coated antibacterial metal surfaces important for environmental and biomedical applications.
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Affiliation(s)
- Sunita Panda
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT) University, Bhubaneswar, Odisha, 751024, India
| | - Tapan K Rout
- Tata Steel Limited, Jajpur, Odisha, 755026, India
| | - Agnish Dev Prusty
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, 751007, India
| | - Pulickel M Ajayan
- Department of Materials Science and Nano Engineering, Rice University, Houston, TX, 77005, USA
| | - Sasmita Nayak
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT) University, Bhubaneswar, Odisha, 751024, India
- Kalinga Institute of Medical Sciences, Kalinga Institute of Industrial Technology (KIIT) University, Bhubaneswar, Odisha, 751024, India
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134
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Hall CW, Mah TF. Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria. FEMS Microbiol Rev 2018; 41:276-301. [PMID: 28369412 DOI: 10.1093/femsre/fux010] [Citation(s) in RCA: 849] [Impact Index Per Article: 141.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/22/2017] [Indexed: 02/06/2023] Open
Abstract
Biofilms are surface-attached groups of microbial cells encased in an extracellular matrix that are significantly less susceptible to antimicrobial agents than non-adherent, planktonic cells. Biofilm-based infections are, as a result, extremely difficult to cure. A wide range of molecular mechanisms contribute to the high degree of recalcitrance that is characteristic of biofilm communities. These mechanisms include, among others, interaction of antimicrobials with biofilm matrix components, reduced growth rates and the various actions of specific genetic determinants of antibiotic resistance and tolerance. Alone, each of these mechanisms only partially accounts for the increased antimicrobial recalcitrance observed in biofilms. Acting in concert, however, these defences help to ensure the survival of biofilm cells in the face of even the most aggressive antimicrobial treatment regimens. This review summarises both historical and recent scientific data in support of the known biofilm resistance and tolerance mechanisms. Additionally, suggestions for future work in the field are provided.
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135
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Albers P, Weytjens B, De Mot R, Marchal K, Springael D. Molecular processes underlying synergistic linuron mineralization in a triple-species bacterial consortium biofilm revealed by differential transcriptomics. Microbiologyopen 2018; 7:e00559. [PMID: 29314727 PMCID: PMC5911999 DOI: 10.1002/mbo3.559] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 10/16/2017] [Indexed: 01/28/2023] Open
Abstract
The proteobacteria Variovorax sp. WDL1, Comamonas testosteroni WDL7, and Hyphomicrobium sulfonivorans WDL6 compose a triple‐species consortium that synergistically degrades and grows on the phenylurea herbicide linuron. To acquire a better insight into the interactions between the consortium members and the underlying molecular mechanisms, we compared the transcriptomes of the key biodegrading strains WDL7 and WDL1 grown as biofilms in either isolation or consortium conditions by differential RNAseq analysis. Differentially expressed pathways and cellular systems were inferred using the network‐based algorithm PheNetic. Coculturing affected mainly metabolism in WDL1. Significantly enhanced expression of hylA encoding linuron hydrolase was observed. Moreover, differential expression of several pathways involved in carbohydrate, amino acid, nitrogen, and sulfur metabolism was observed indicating that WDL1 gains carbon and energy from linuron indirectly by consuming excretion products from WDL7 and/or WDL6. Moreover, in consortium conditions, WDL1 showed a pronounced stress response and overexpression of cell to cell interaction systems such as quorum sensing, contact‐dependent inhibition, and Type VI secretion. Since the latter two systems can mediate interference competition, it prompts the question if synergistic linuron degradation is the result of true adaptive cooperation or rather a facultative interaction between bacteria that coincidentally occupy complementary metabolic niches.
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Affiliation(s)
- Pieter Albers
- Division of Soil and Water Management, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
| | - Bram Weytjens
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.,Department of Information Technology, IDLab, IMEC, Ghent University, Gent, Belgium.,Bioinformatics Institute Ghent, Gent, Belgium
| | - René De Mot
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Kathleen Marchal
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.,Department of Information Technology, IDLab, IMEC, Ghent University, Gent, Belgium.,Bioinformatics Institute Ghent, Gent, Belgium
| | - Dirk Springael
- Division of Soil and Water Management, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
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136
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Slachmuylders L, Van Acker H, Brackman G, Sass A, Van Nieuwerburgh F, Coenye T. Elucidation of the mechanism behind the potentiating activity of baicalin against Burkholderia cenocepacia biofilms. PLoS One 2018; 13:e0190533. [PMID: 29293658 PMCID: PMC5749847 DOI: 10.1371/journal.pone.0190533] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/16/2017] [Indexed: 11/19/2022] Open
Abstract
Reduced antimicrobial susceptibility due to resistance and tolerance has become a serious threat to human health. An approach to overcome this reduced susceptibility is the use of antibiotic adjuvants, also known as potentiators. These are compounds that have little or no antibacterial effect on their own but increase the susceptibility of bacterial cells towards antimicrobial agents. Baicalin hydrate, previously described as a quorum sensing inhibitor, is such a potentiator that increases the susceptibility of Burkholderia cenocepacia J2315 biofilms towards tobramycin. The goal of the present study is to elucidate the molecular mechanisms behind the potentiating activity of baicalin hydrate and related flavonoids. We first determined the effect of multiple flavonoids on susceptibility of B. cenocepacia J2315 towards tobramycin. Increased antibiotic susceptibility was most pronounced in combination with apigenin 7-O-glucoside and baicalin hydrate. For baicalin hydrate, also other B. cepacia complex strains and other antibiotics were tested. The potentiating effect was only observed for aminoglycosides and was both strain- and aminoglycoside-dependent. Subsequently, gene expression was compared between baicalin hydrate treated and untreated cells, in the presence and absence of tobramycin. This revealed that baicalin hydrate affected cellular respiration, resulting in increased reactive oxygen species production in the presence of tobramycin. We subsequently showed that baicalin hydrate has an impact on oxidative stress via several pathways including oxidative phosphorylation, glucarate metabolism and by modulating biosynthesis of putrescine. Furthermore, our data strongly suggest that the influence of baicalin hydrate on oxidative stress is unrelated to quorum sensing. Our data indicate that the potentiating effect of baicalin hydrate is due to modulating the oxidative stress response, which in turn leads to increased tobramycin-mediated killing.
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Affiliation(s)
- Lisa Slachmuylders
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Gilles Brackman
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Andrea Sass
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | | | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- * E-mail:
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137
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Fe-S Clusters Emerging as Targets of Therapeutic Drugs. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:3647657. [PMID: 29445445 PMCID: PMC5763138 DOI: 10.1155/2017/3647657] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 01/11/2023]
Abstract
Fe-S centers exhibit strong electronic plasticity, which is of importance for insuring fine redox tuning of protein biological properties. In accordance, Fe-S clusters are also highly sensitive to oxidation and can be very easily altered in vivo by different drugs, either directly or indirectly due to catabolic by-products, such as nitric oxide species (NOS) or reactive oxygen species (ROS). In case of metal ions, Fe-S cluster alteration might be the result of metal liganding to the coordinating sulfur atoms, as suggested for copper. Several drugs presented through this review are either capable of direct interaction with Fe-S clusters or of secondary Fe-S clusters alteration following ROS or NOS production. Reactions leading to Fe-S cluster disruption are also reported. Due to the recent interest and progress in Fe-S biology, it is very likely that an increasing number of drugs already used in clinics will emerge as molecules interfering with Fe-S centers in the near future. Targeting Fe-S centers could also become a promising strategy for drug development.
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138
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Arias-Sánchez FI, Allen RC, Hall AR. Effects of prior exposure to antibiotics on bacterial adaptation to phages. J Evol Biol 2017; 31:277-286. [PMID: 29218855 DOI: 10.1111/jeb.13220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 11/30/2017] [Indexed: 11/27/2022]
Abstract
Understanding adaptation to complex environments requires information about how exposure to one selection pressure affects adaptation to others. For bacteria, antibiotics and viral parasites (phages) are two of the most common selection pressures and are both relevant for treatment of bacterial infections: increasing antibiotic resistance is generating significant interest in using phages in addition or as an alternative to antibiotics. However, we lack knowledge of how exposure to antibiotics affects bacterial responses to phages. Specifically, it is unclear how the negative effects of antibiotics on bacterial population growth combine with any possible mutagenic effects or physiological responses to influence adaptation to other stressors such as phages, and how this net effect varies with antibiotic concentration. Here, we experimentally addressed the effect of pre-exposure to a wide range of antibiotic concentrations on bacterial responses to phages. Across 10 antibiotics, we found a strong association between their effects on bacterial population size and subsequent population growth in the presence of phages (which in these conditions indicates phage-resistance evolution). We detected some evidence of mutagenesis among populations treated with fluoroquinolones and β-lactams at sublethal doses, but these effects were small and not consistent across phage treatments. These results show that, although stressors such as antibiotics can boost adaptation to other stressors at low concentrations, these effects are weak compared to the effect of reduced population growth at inhibitory concentrations, which in our experiments strongly reduced the likelihood of subsequent phage-resistance evolution.
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Affiliation(s)
| | - R C Allen
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - A R Hall
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
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139
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El Khoury JY, Boucher N, Bergeron MG, Leprohon P, Ouellette M. Penicillin induces alterations in glutamine metabolism in Streptococcus pneumoniae. Sci Rep 2017; 7:14587. [PMID: 29109543 PMCID: PMC5673960 DOI: 10.1038/s41598-017-15035-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/19/2017] [Indexed: 11/09/2022] Open
Abstract
Penicillin is a bactericidal antibiotic that inhibits the synthesis of the peptidoglycan by targeting penicillin-binding proteins. This study aimed to assess through transcriptional profiling the stress response of S. pneumoniae strains after exposure to lethal penicillin concentrations to understand further the mode of action of penicillin. Two experimental designs (time-course and dose-response) were used for monitoring the effect of penicillin on the transcriptional profile. The expression of some genes previously shown to be modulated by penicillin was altered, including ciaRH, pstS and clpL. Genes of the glnRA and glnPQ operons were among the most downregulated genes in the three strains. These genes are involved in glutamine synthesis and uptake and LC-MS work confirmed that penicillin treatment increases the intracellular glutamine concentrations. Glutamine conferred a protective role against penicillin when added to the culture medium. Glutamine synthetase encoded by glnA catalyses the transformation of glutamate and ammonium into glutamine and its chemical inhibition by the inhibitor L-methionine sulfoximine is shown to sensitize S. pneumoniae to penicillin, including penicillin-resistant clinical isolates. In summary, a combination of RNA-seq and metabolomics revealed that penicillin interferes with glutamine metabolism suggesting strategies that could eventually be exploited for combination therapy or for reversal of resistance.
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Affiliation(s)
- Jessica Y El Khoury
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Nancy Boucher
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Michel G Bergeron
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Philippe Leprohon
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Marc Ouellette
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada.
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140
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Courtney CM, Goodman SM, Nagy TA, Levy M, Bhusal P, Madinger NE, Detweiler CS, Nagpal P, Chatterjee A. Potentiating antibiotics in drug-resistant clinical isolates via stimuli-activated superoxide generation. SCIENCE ADVANCES 2017; 3:e1701776. [PMID: 28983513 PMCID: PMC5627983 DOI: 10.1126/sciadv.1701776] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/13/2017] [Indexed: 05/25/2023]
Abstract
The rise of multidrug-resistant (MDR) bacteria is a growing concern to global health and is exacerbated by the lack of new antibiotics. To treat already pervasive MDR infections, new classes of antibiotics or antibiotic adjuvants are needed. Reactive oxygen species (ROS) have been shown to play a role during antibacterial action; however, it is not yet understood whether ROS contribute directly to or are an outcome of bacterial lethality caused by antibiotics. We show that a light-activated nanoparticle, designed to produce tunable flux of specific ROS, superoxide, potentiates the activity of antibiotics in clinical MDR isolates of Escherichia coli, Salmonella enterica, and Klebsiella pneumoniae. Despite the high degree of antibiotic resistance in these isolates, we observed a synergistic interaction between both bactericidal and bacteriostatic antibiotics with varied mechanisms of action and our superoxide-producing nanoparticles in more than 75% of combinations. As a result of this potentiation, the effective antibiotic concentration of the clinical isolates was reduced up to 1000-fold below their respective sensitive/resistant breakpoint. Further, superoxide-generating nanoparticles in combination with ciprofloxacin reduced bacterial load in epithelial cells infected with S. enterica serovar Typhimurium and increased Caenorhabditis elegans survival upon infection with S. enterica serovar Enteriditis, compared to antibiotic alone. This demonstration highlights the ability to engineer superoxide generation to potentiate antibiotic activity and combat highly drug-resistant bacterial pathogens.
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Affiliation(s)
- Colleen M. Courtney
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Samuel M. Goodman
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Toni A. Nagy
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Max Levy
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Pallavi Bhusal
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Nancy E. Madinger
- Division of Infectious Diseases, University of Colorado Denver, Aurora, CO 80045, USA
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Prashant Nagpal
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA
- Materials Science and Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Anushree Chatterjee
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA
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141
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Use antibiotics in cell culture with caution: genome-wide identification of antibiotic-induced changes in gene expression and regulation. Sci Rep 2017; 7:7533. [PMID: 28790348 PMCID: PMC5548911 DOI: 10.1038/s41598-017-07757-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 06/29/2017] [Indexed: 01/29/2023] Open
Abstract
Standard cell culture guidelines often use media supplemented with antibiotics to prevent cell contamination. However, relatively little is known about the effect of antibiotic use in cell culture on gene expression and the extent to which this treatment could confound results. To comprehensively characterize the effect of antibiotic treatment on gene expression, we performed RNA-seq and ChIP-seq for H3K27ac on HepG2 cells, a human liver cell line commonly used for pharmacokinetic, metabolism and genomic studies, cultured in media supplemented with penicillin-streptomycin (PenStrep) or vehicle control. We identified 209 PenStrep-responsive genes, including transcription factors such as ATF3 that are likely to alter the regulation of other genes. Pathway analyses found a significant enrichment for "xenobiotic metabolism signaling" and "PXR/RXR activation" pathways. Our H3K27ac ChIP-seq identified 9,514 peaks that are PenStrep responsive. These peaks were enriched near genes that function in cell differentiation, tRNA modification, nuclease activity and protein dephosphorylation. Our results suggest that PenStrep treatment can significantly alter gene expression and regulation in a common liver cell type such as HepG2, advocating that antibiotic treatment should be taken into account when carrying out genetic, genomic or other biological assays in cultured cells.
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142
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de la Campa AG, Ferrándiz MJ, Martín-Galiano AJ, García MT, Tirado-Vélez JM. The Transcriptome of Streptococcus pneumoniae Induced by Local and Global Changes in Supercoiling. Front Microbiol 2017; 8:1447. [PMID: 28824578 PMCID: PMC5534458 DOI: 10.3389/fmicb.2017.01447] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/17/2017] [Indexed: 01/28/2023] Open
Abstract
The bacterial chromosome is compacted in a manner optimal for DNA transactions to occur. The degree of compaction results from the level of DNA-supercoiling and the presence of nucleoid-binding proteins. DNA-supercoiling is homeostatically maintained by the opposing activities of relaxing DNA topoisomerases and negative supercoil-inducing DNA gyrase. DNA-supercoiling acts as a general cis regulator of transcription, which can be superimposed upon other types of more specific trans regulatory mechanism. Transcriptomic studies on the human pathogen Streptococcus pneumoniae, which has a relatively small genome (∼2 Mb) and few nucleoid-binding proteins, have been performed under conditions of local and global changes in supercoiling. The response to local changes induced by fluoroquinolone antibiotics, which target DNA gyrase subunit A and/or topoisomerase IV, involves an increase in oxygen radicals which reduces cell viability, while the induction of global supercoiling changes by novobiocin (a DNA gyrase subunit B inhibitor), or by seconeolitsine (a topoisomerase I inhibitor), has revealed the existence of topological domains that specifically respond to such changes. The control of DNA-supercoiling in S. pneumoniae occurs mainly via the regulation of topoisomerase gene transcription: relaxation triggers the up-regulation of gyrase and the down-regulation of topoisomerases I and IV, while hypernegative supercoiling down-regulates the expression of topoisomerase I. Relaxation affects 13% of the genome, with the majority of the genes affected located in 15 domains. Hypernegative supercoiling affects 10% of the genome, with one quarter of the genes affected located in 12 domains. However, all the above domains overlap, suggesting that the chromosome is organized into topological domains with fixed locations. Based on its response to relaxation, the pneumococcal chromosome can be said to be organized into five types of domain: up-regulated, down-regulated, position-conserved non-regulated, position-variable non-regulated, and AT-rich. The AT content is higher in the up-regulated than in the down-regulated domains. Genes within the different domains share structural and functional characteristics. It would seem that a topology-driven selection pressure has defined the chromosomal location of the metabolism, virulence and competence genes, which suggests the existence of topological rules that aim to improve bacterial fitness.
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Affiliation(s)
- Adela G de la Campa
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain.,Presidencia, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - María J Ferrándiz
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain
| | - Antonio J Martín-Galiano
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain
| | - María T García
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad ComplutenseMadrid, Spain
| | - Jose M Tirado-Vélez
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain
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143
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Machuca J, Recacha E, Briales A, Díaz-de-Alba P, Blazquez J, Pascual Á, Rodríguez-Martínez JM. Cellular Response to Ciprofloxacin in Low-Level Quinolone-Resistant Escherichia coli. Front Microbiol 2017; 8:1370. [PMID: 28769919 PMCID: PMC5516121 DOI: 10.3389/fmicb.2017.01370] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/05/2017] [Indexed: 11/13/2022] Open
Abstract
Bactericidal activity of quinolones has been related to a combination of DNA fragmentation, reactive oxygen species (ROS) production and programmed cell death (PCD) systems. The underlying molecular systems responsible for reducing bactericidal effect during antimicrobial therapy in low-level quinolone resistance (LLQR) phenotypes need to be clarified. To do this and also define possible new antimicrobial targets, the transcriptome profile of isogenic Escherichia coli harboring quinolone resistance mechanisms in the presence of a clinical relevant concentration of ciprofloxacin was evaluated. A marked differential response to ciprofloxacin of either up- or downregulation was observed in LLQR strains. Multiple genes implicated in ROS modulation (related to the TCA cycle, aerobic respiration and detoxification systems) were upregulated (sdhC up to 63.5-fold) in mutants with LLQR. SOS system components were downregulated (recA up to 30.7-fold). yihE, a protective kinase coding for PCD, was also upregulated (up to 5.2-fold). SdhC inhibition sensitized LLQR phenotypes (up to ΔLog = 2.3 after 24 h). At clinically relevant concentrations of ciprofloxacin, gene expression patterns in critical systems to bacterial survival and mutant development were significantly modified in LLQR phenotypes. Chemical inhibition of SdhC (succinate dehydrogenase) validated modulation of ROS as an interesting target for bacterial sensitization.
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Affiliation(s)
- Jesús Machuca
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
| | - Esther Recacha
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
| | - Alejandra Briales
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Departamento de Microbiología, Universidad de SevillaSevilla, Spain
| | - Paula Díaz-de-Alba
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
| | - Jesús Blazquez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Álvaro Pascual
- Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena y Virgen del RocíoSeville, Spain
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
| | - José-Manuel Rodríguez-Martínez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de SevillaSevilla, Spain
- Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
- Departamento de Microbiología, Universidad de SevillaSevilla, Spain
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144
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Bodine TJ, Evangelista MA, Chang HT, Ayoub CA, Samuel BS, Sucgang R, Zechiedrich L. Escherichia coli DNA ligase B may mitigate damage from oxidative stress. PLoS One 2017; 12:e0180800. [PMID: 28700629 PMCID: PMC5507437 DOI: 10.1371/journal.pone.0180800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 06/21/2017] [Indexed: 01/02/2023] Open
Abstract
Escherichia coli encodes two DNA ligases, ligase A, which is essential under normal laboratory growth conditions, and ligase B, which is not. Here we report potential functions of ligase B. We found that across the entire Enterobacteriaceae family, ligase B is highly conserved in both amino acid identity and synteny with genes associated with oxidative stress. Deletion of ligB sensitized E. coli to specific DNA damaging agents and antibiotics resulted in a weak mutator phenotype, and decreased biofilm formation. Overexpression of ligB caused a dramatic extension of lag phase that eventually resumed normal growth. The ligase function of ligase B was not required to mediate the extended lag phase, as overexpression of a ligase-deficient ligB mutant also blocked growth. Overexpression of ligB during logarithmic growth caused an immediate block of cell growth and DNA replication, and death of about half of cells. These data support a potential role for ligase B in the base excision repair pathway or the mismatch repair pathway.
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Affiliation(s)
- Truston J. Bodine
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, United States of America
| | - Michael A. Evangelista
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Huan Ting Chang
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
- Department of BioSciences, Rice University, Houston, TX, United States of America
| | - Christopher A. Ayoub
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
| | - Buck S. Samuel
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX, United States of America
| | - Richard Sucgang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Lynn Zechiedrich
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States of America
- Department of Pharmacology, Baylor College of Medicine, Houston, TX, United States of America
- * E-mail:
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145
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DNA Backbone Sulfur-Modification Expands Microbial Growth Range under Multiple Stresses by its anti-oxidation function. Sci Rep 2017; 7:3516. [PMID: 28615635 PMCID: PMC5471199 DOI: 10.1038/s41598-017-02445-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 04/11/2017] [Indexed: 11/26/2022] Open
Abstract
DNA phosphorothioate (PT) modification is a sulfur modification on the backbone of DNA introduced by the proteins DndA-E. It has been detected within many bacteria isolates and metagenomic datasets, including human pathogens, and is considered to be widely distributed in nature. However, little is known about the physiological function of this modification, and thus its evolutionary significance and application potential remains largely a mystery. In this study, we focused on the advantages of DNA PT modification to bacterial cells coping with environmental stresses. We show that the mesophile Escherichia coli and the extremophile Shewanella piezotolerans both expanded their growth ranges following exposure to extreme temperature, salinity, pH, pressure, UV, X-ray and heavy metals as a result of DNA phophorothioation. The phophorothioated DNA reacted to both H2O2 and hydroxyl radicals in vivo, and protected genomic DNA as well as sensitive enzymes from intracellular oxidative damage. We further demonstrate that this process has evolved separate from its associated role in DNA restriction and modification. These findings provide a physiological role for a covalent modification widespread in nature and suggest possible applications in biotechnology and biomedicine.
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146
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Guzmán-Trampe S, Ceapa CD, Manzo-Ruiz M, Sánchez S. Synthetic biology era: Improving antibiotic’s world. Biochem Pharmacol 2017; 134:99-113. [DOI: 10.1016/j.bcp.2017.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/26/2017] [Indexed: 12/12/2022]
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147
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Nandi R, Mishra S, Maji TK, Manna K, Kar P, Banerjee S, Dutta S, Sharma SK, Lemmens P, Saha KD, Pal SK. A novel nanohybrid for cancer theranostics: folate sensitized Fe 2O 3 nanoparticles for colorectal cancer diagnosis and photodynamic therapy. J Mater Chem B 2017; 5:3927-3939. [PMID: 32264254 DOI: 10.1039/c6tb03292c] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Organic-inorganic nanohybrids are becoming popular for their potential biological applications, including diagnosis and treatment of cancerous cells. The motive of this study is to synthesise a nanohybrid for the diagnosis and therapy of colorectal cancer. Here we have developed a facile and cost-effective synthesis of folic acid (FA) templated Fe2O3 nanoparticles with excellent colloidal stability in water using a hydrothermal method for the theranostics applications. The attachment of FA to Fe2O3 was confirmed using various spectroscopic techniques including FTIR and picosecond resolved fluorescence studies. The nanohybrid (FA-Fe2O3) is a combination of two nontoxic ingredients FA and Fe2O3, showing remarkable photodynamic therapeutic (PDT) activity in human colorectal carcinoma cell lines (HCT 116) via generation of intracellular ROS. The light induced enhanced ROS activity of the nanohybrid causes significant nuclear DNA damage, as confirmed from the comet assay. Assessment of p53, Bax, Bcl2, cytochrome c (cyt c) protein expression and caspase 9/3 activity provides vivid evidence for cell death via an apoptotic pathway. In vitro magnetic resonance imaging (MRI) experiments in folate receptor (FR) overexpressed cancer cells (HCT 116) and FR deficient human embryonic kidney cells (HEK 293) reveal the target specificity of the nanohybrid towards cancer cells, and are thus pronounced MRI contrasting agents for the diagnosis of colorectal cancer.
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Affiliation(s)
- Ramesh Nandi
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
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148
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Untargeted metabolomics analysis reveals key pathways responsible for the synergistic killing of colistin and doripenem combination against Acinetobacter baumannii. Sci Rep 2017; 7:45527. [PMID: 28358014 PMCID: PMC5371981 DOI: 10.1038/srep45527] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/28/2017] [Indexed: 12/21/2022] Open
Abstract
Combination therapy is deployed for the treatment of multidrug-resistant Acinetobacter baumannii, as it can rapidly develop resistance to current antibiotics. This is the first study to investigate the synergistic effect of colistin/doripenem combination on the metabolome of A. baumannii. The metabolite levels were measured using LC-MS following treatment with colistin (2 mg/L) or doripenem (25 mg/L) alone, and their combination at 15 min, 1 hr and 4 hr (n = 4). Colistin caused early (15 min and 1 hr) disruption of the bacterial outer membrane and cell wall, as demonstrated by perturbation of glycerophospholipids and fatty acids. Concentrations of peptidoglycan biosynthesis metabolites decreased at 4 hr by doripenem alone, reflecting its mechanism of action. The combination induced significant changes to more key metabolic pathways relative to either monotherapy. Down-regulation of cell wall biosynthesis (via D-sedoheptulose 7-phosphate) and nucleotide metabolism (via D-ribose 5-phosphate) was associated with perturbations in the pentose phosphate pathway induced initially by colistin (15 min and 1 hr) and later by doripenem (4 hr). We discovered that the combination synergistically killed A. baumannii via time-dependent inhibition of different key metabolic pathways. Our study highlights the significant potential of systems pharmacology in elucidating the mechanism of synergy and optimizing antibiotic pharmacokinetics/pharmacodynamics.
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149
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Li XM, Liu J, Du YK, Wen ZG, Wang JT, Yang PL. Antibacterial activity and mechanism of the ethanol extracts from Sonchus brachyotus DC. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2017. [DOI: 10.1080/10942912.2016.1261152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Xiu-Mei Li
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Jing Liu
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Yong-Kai Du
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Zhi-Guo Wen
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Ji-Tong Wang
- Beijing Institute of Food Control, Beijing Municipal Bureau of Agriculture, Beijing, P.R. China
| | - Pei-Long Yang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
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150
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Larsen EL, Cejvanovic V, Kjaer LK, Pedersen MT, Popik SD, Hansen LK, Andersen JT, Jimenez-Solem E, Broedbaek K, Petersen M, Weimann A, Henriksen T, Lykkesfeldt J, Torp-Pedersen C, Poulsen HE. Clarithromycin, trimethoprim, and penicillin and oxidative nucleic acid modifications in humans: randomised, controlled trials. Br J Clin Pharmacol 2017; 83:1643-1653. [PMID: 28185274 DOI: 10.1111/bcp.13261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 12/29/2022] Open
Abstract
AIMS In vitro studies have demonstrated that formation of reactive oxygen species (ROS) contributes to the effect of bactericidal antibiotics. The formation of ROS is not restricted to bacteria, but also occurs in mammalian cells. Oxidative stress is linked to several diseases. This study investigates whether antibiotic drugs induce oxidative stress in healthy humans as a possible mechanism for adverse reactions to the antibiotic drugs. METHODS This study contains information from two randomised, controlled trials. Participants underwent 1 week treatment with clarithromycin, trimethoprim, phenoxymethylpenicillin (penicillin V), or placebo. Oxidative modifications were measured as 24-h urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and plasma levels of malondialdehyde before and after treatment as a measurement of DNA oxidation, RNA oxidation, and lipid peroxidation, respectively. RESULTS Clarithromycin significantly increased urinary excretion of 8-oxodG by 22.0% (95% confidence interval (CI): 3.6-40.4%) and 8-oxoGuo by 14.9% (95% CI: 3.7-26.1%). Further, we demonstrated that trimethoprim significantly lowered urinary excretion of 8-oxodG by 21.7% (95% CI: 5.8-37.6%), but did not influence urinary excretion of 8-oxoGuo. Penicillin V did not influence urinary excretion of 8-oxodG or 8-oxoGuo. None of the antibiotic drugs influenced plasma levels of malondialdehyde. CONCLUSION Clarithromycin significantly increases oxidative nucleic acid modifications. Increased oxidative modifications might explain some of clarithromycin's known adverse reactions. Trimethoprim significantly lowers DNA oxidation but not RNA oxidation. Penicillin V had no effect on oxidative nucleic acid modifications.
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Affiliation(s)
- Emil List Larsen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Vanja Cejvanovic
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Laura Kofoed Kjaer
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Thorup Pedersen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sara Daugaard Popik
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Lina Kallehave Hansen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jon Traerup Andersen
- Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Espen Jimenez-Solem
- Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Broedbaek
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Morten Petersen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Allan Weimann
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Trine Henriksen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens Lykkesfeldt
- Section of Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | | | - Henrik Enghusen Poulsen
- Laboratory of Clinical Pharmacology (Q7642), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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