1
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Moreau F, Atamanyuk D, Blaukopf M, Barath M, Herczeg M, Xavier NM, Monbrun J, Airiau E, Henryon V, Leroy F, Floquet S, Bonnard D, Szabla R, Brown C, Junop MS, Kosma P, Gerusz V. Potentiating Activity of GmhA Inhibitors on Gram-Negative Bacteria. J Med Chem 2024; 67:6610-6623. [PMID: 38598312 PMCID: PMC11056994 DOI: 10.1021/acs.jmedchem.4c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/28/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
Inhibition of the biosynthesis of bacterial heptoses opens novel perspectives for antimicrobial therapies. The enzyme GmhA responsible for the first committed biosynthetic step catalyzes the conversion of sedoheptulose 7-phosphate into d-glycero-d-manno-heptose 7-phosphate and harbors a Zn2+ ion in the active site. A series of phosphoryl- and phosphonyl-substituted derivatives featuring a hydroxamate moiety were designed and prepared from suitably protected ribose or hexose derivatives. High-resolution crystal structures of GmhA complexed to two N-formyl hydroxamate inhibitors confirmed the binding interactions to a central Zn2+ ion coordination site. Some of these compounds were found to be nanomolar inhibitors of GmhA. While devoid of HepG2 cytotoxicity and antibacterial activity of their own, they demonstrated in vitro lipopolysaccharide heptosylation inhibition in Enterobacteriaceae as well as the potentiation of erythromycin and rifampicin in a wild-type Escherichia coli strain. These inhibitors pave the way for a novel treatment of Gram-negative infections.
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Affiliation(s)
- François Moreau
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
| | | | - Markus Blaukopf
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
| | - Marek Barath
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Institute
of Chemistry, Center for Glycomics, Slovak
Academy of Sciences, Dúbravská cesta 9, Bratislava SK-845 38, Slovakia
| | - Mihály Herczeg
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Department
of Pharmaceutical Chemistry, University
of Debrecen, Debrecen 4032, Hungary
| | - Nuno M. Xavier
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
- Centro
de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, 5° Piso, Campo Grande, Lisboa 1749-016, Portugal
| | | | | | | | - Frédéric Leroy
- Carbosynth
Limited, 8&9 Old
Station Business Park, Compton, Berkshire RG20 6NE, U.K.
| | | | - Damien Bonnard
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
| | - Robert Szabla
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Chris Brown
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Murray S. Junop
- Department
of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Paul Kosma
- Department
of Chemistry, University of Natural Resources
and Life Sciences, Muthgasse
18, Vienna A-1190, Austria
| | - Vincent Gerusz
- Mutabilis, 102 Avenue Gaston Roussel, Romainville 93230, France
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2
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Monterroso B, Margolin W, Boersma AJ, Rivas G, Poolman B, Zorrilla S. Macromolecular Crowding, Phase Separation, and Homeostasis in the Orchestration of Bacterial Cellular Functions. Chem Rev 2024; 124:1899-1949. [PMID: 38331392 PMCID: PMC10906006 DOI: 10.1021/acs.chemrev.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/01/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024]
Abstract
Macromolecular crowding affects the activity of proteins and functional macromolecular complexes in all cells, including bacteria. Crowding, together with physicochemical parameters such as pH, ionic strength, and the energy status, influences the structure of the cytoplasm and thereby indirectly macromolecular function. Notably, crowding also promotes the formation of biomolecular condensates by phase separation, initially identified in eukaryotic cells but more recently discovered to play key functions in bacteria. Bacterial cells require a variety of mechanisms to maintain physicochemical homeostasis, in particular in environments with fluctuating conditions, and the formation of biomolecular condensates is emerging as one such mechanism. In this work, we connect physicochemical homeostasis and macromolecular crowding with the formation and function of biomolecular condensates in the bacterial cell and compare the supramolecular structures found in bacteria with those of eukaryotic cells. We focus on the effects of crowding and phase separation on the control of bacterial chromosome replication, segregation, and cell division, and we discuss the contribution of biomolecular condensates to bacterial cell fitness and adaptation to environmental stress.
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Affiliation(s)
- Begoña Monterroso
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - William Margolin
- Department
of Microbiology and Molecular Genetics, McGovern Medical School, UTHealth-Houston, Houston, Texas 77030, United States
| | - Arnold J. Boersma
- Cellular
Protein Chemistry, Bijvoet Centre for Biomolecular Research, Faculty
of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Germán Rivas
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - Bert Poolman
- Department
of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Silvia Zorrilla
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
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3
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Chosy MB, Sun J, Rahn HP, Liu X, Brčić J, Wender PA, Cegelski L. Vancomycin-Polyguanidino Dendrimer Conjugates Inhibit Growth of Antibiotic-Resistant Gram-Positive and Gram-Negative Bacteria and Eradicate Biofilm-Associated S. aureus. ACS Infect Dis 2024; 10:384-397. [PMID: 38252999 DOI: 10.1021/acsinfecdis.3c00168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The global challenge of antibiotic resistance necessitates the introduction of more effective antibiotics. Here we report a potentially general design strategy, exemplified with vancomycin, that improves and expands antibiotic performance. Vancomycin is one of the most important antibiotics in use today for the treatment of Gram-positive infections. However, it fails to eradicate difficult-to-treat biofilm populations. Vancomycin is also ineffective in killing Gram-negative bacteria due to its inability to breach the outer membrane. Inspired by our seminal studies on cell penetrating guanidinium-rich transporters (e.g., octaarginine), we recently introduced vancomycin conjugates that effectively eradicate Gram-positive biofilm bacteria, persister cells and vancomycin-resistant enterococci (with V-r8, vancomycin-octaarginine), and Gram-negative pathogens (with V-R, vancomycin-arginine). Having shown previously that the spatial array (linear versus dendrimeric) of multiple guanidinium groups affects cell permeation, we report here for the first time vancomycin conjugates with dendrimerically displayed guanidinium groups that exhibit superior efficacy and breadth, presenting the best activity of V-r8 and V-R in single broad-spectrum compounds active against ESKAPE pathogens. Mode-of-action studies reveal cell-surface activity and enhanced vancomycin-like killing. The vancomycin-polyguanidino dendrimer conjugates exhibit no acute mammalian cell toxicity or hemolytic activity. Our study introduces a new class of broad-spectrum vancomycin derivatives and a general strategy to improve or expand antibiotic performance through combined mode-of-action and function-oriented design studies.
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Affiliation(s)
- Madeline B Chosy
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jiuzhi Sun
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Harrison P Rahn
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Xinyu Liu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jasna Brčić
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Paul A Wender
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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4
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Pahil KS, Gilman MSA, Baidin V, Clairfeuille T, Mattei P, Bieniossek C, Dey F, Muri D, Baettig R, Lobritz M, Bradley K, Kruse AC, Kahne D. A new antibiotic traps lipopolysaccharide in its intermembrane transporter. Nature 2024; 625:572-577. [PMID: 38172635 PMCID: PMC10794137 DOI: 10.1038/s41586-023-06799-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 10/30/2023] [Indexed: 01/05/2024]
Abstract
Gram-negative bacteria are extraordinarily difficult to kill because their cytoplasmic membrane is surrounded by an outer membrane that blocks the entry of most antibiotics. The impenetrable nature of the outer membrane is due to the presence of a large, amphipathic glycolipid called lipopolysaccharide (LPS) in its outer leaflet1. Assembly of the outer membrane requires transport of LPS across a protein bridge that spans from the cytoplasmic membrane to the cell surface. Maintaining outer membrane integrity is essential for bacterial cell viability, and its disruption can increase susceptibility to other antibiotics2-6. Thus, inhibitors of the seven lipopolysaccharide transport (Lpt) proteins that form this transenvelope transporter have long been sought. A new class of antibiotics that targets the LPS transport machine in Acinetobacter was recently identified. Here, using structural, biochemical and genetic approaches, we show that these antibiotics trap a substrate-bound conformation of the LPS transporter that stalls this machine. The inhibitors accomplish this by recognizing a composite binding site made up of both the Lpt transporter and its LPS substrate. Collectively, our findings identify an unusual mechanism of lipid transport inhibition, reveal a druggable conformation of the Lpt transporter and provide the foundation for extending this class of antibiotics to other Gram-negative pathogens.
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Affiliation(s)
- Karanbir S Pahil
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Morgan S A Gilman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Vadim Baidin
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Thomas Clairfeuille
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Patrizio Mattei
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Christoph Bieniossek
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Fabian Dey
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Dieter Muri
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Remo Baettig
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Michael Lobritz
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Kenneth Bradley
- Departments of Immunology, Infectious Disease and Ophthalmology (I2O), Medicinal Chemistry and Lead Discovery, Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
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5
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Ambite I, Tran TH, Butler DSC, Cavalera M, Wan MLY, Ahmadi S, Svanborg C. Therapeutic Effects of IL-1RA against Acute Bacterial Infections, including Antibiotic-Resistant Strains. Pathogens 2023; 13:42. [PMID: 38251349 PMCID: PMC10820880 DOI: 10.3390/pathogens13010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/25/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
Innate immunity is essential for the anti-microbial defense, but excessive immune activation may cause severe disease. In this study, immunotherapy was shown to prevent excessive innate immune activation and restore the anti-bacterial defense. E. coli-infected Asc-/- mice develop severe acute cystitis, defined by IL-1 hyper-activation, high bacterial counts, and extensive tissue pathology. Here, the interleukin-1 receptor antagonist (IL-1RA), which inhibits IL-1 hyper-activation in acute cystitis, was identified as a more potent inhibitor of inflammation and NK1R- and substance P-dependent pain than cefotaxime. Furthermore, IL-1RA treatment inhibited the excessive innate immune activation in the kidneys of infected Irf3-/- mice and restored tissue integrity. Unexpectedly, IL-1RA also accelerated bacterial clearance from infected bladders and kidneys, including antibiotic-resistant E. coli, where cefotaxime treatment was inefficient. The results suggest that by targeting the IL-1 response, control of the innate immune response to infection may be regained, with highly favorable treatment outcomes, including infections caused by antibiotic-resistant strains.
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Affiliation(s)
| | | | | | | | | | | | - Catharina Svanborg
- Division of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Faculty of Medicine, Lund University, 221 84 Lund, Sweden; (I.A.); (T.H.T.); (D.S.C.B.); (M.C.); (M.L.Y.W.); (S.A.)
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6
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Zheng L, Zhou R, Jiang B, Chen J, Hu M, Zhang T. Permeabilized whole cells containing co-expressed cyclomaltodextrinase and maltooligosyltrehalose synthase facilitate the synthesis of nonreducing maltoheptaose (N-G7) from β-cyclodextrin. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2023; 103:7061-7069. [PMID: 37337412 DOI: 10.1002/jsfa.12792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/05/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
BACKGROUND Maltodextrin is an important bulk ingredient in food and other industries; however, drawbacks such as uneven polymerization and high reducibility limit its utilization. Nonreducing maltoheptaose (N-G7) is a good substitute for maltodextrin owing to its single degree of polymerization and its nonreducing properties. In this study, in vitro cell factory biotransformation of β-cyclodextrin (β-CD) to N-G7 is demonstrated using coexpressed cyclomaltodextrinase (CDase, EC 3.2.1.54) and maltooligosyltrehalose synthase (MTSase, EC 5.4.99.15). However, the cell membrane prevents β-CD from entering the cell owing to its large diameter. RESULTS The amylase-deficient permeabilized host ΔycjM-ΔmalS-ΔlpxM is utilized for the coexpression of recombinant CDase and MTSase. Deletion of lpxM effectively allows the entry of β-cyclodextrin into the cell, despite its large diameter, without requiring any relevant cell membrane permeability-promoting reagent. This results in a 28.44% increase in the efficiency of β-CD entry into the cell, thus enabling intracellular N-G7 synthesis without the extracellular secretion of recombinant CDase and MTSase. After reacting for 5.5 h, the highest purity of N-G7 (65.50%) is obtained. However, hydrolysis decreases the purity of N-G7 to 49.30%, thus resulting in a conversion rate of 40.16% for N-G7 when the reaction lasts 6 h. Precise control of reaction time is crucial for obtaining high-purity N-G7. CONCLUSION Whole-cell catalysis avoids cell fragmentation and facilitates the creation of an eco-friendly, energy-efficient biotransformation system; thus, it is a promising approach for N-G7 synthesis. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Luhua Zheng
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
| | - Ruiqi Zhou
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
| | - Bo Jiang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Jingjing Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Miaomiao Hu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
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7
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Mikheyeva IV, Sun J, Huang KC, Silhavy TJ. Mechanism of outer membrane destabilization by global reduction of protein content. Nat Commun 2023; 14:5715. [PMID: 37714857 PMCID: PMC10504340 DOI: 10.1038/s41467-023-40396-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 07/26/2023] [Indexed: 09/17/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria such as Escherichia coli is an asymmetric bilayer with the glycolipid lipopolysaccharide (LPS) in the outer leaflet and glycerophospholipids in the inner. Nearly all integral OM proteins (OMPs) have a characteristic β-barrel fold and are assembled in the OM by the BAM complex, which contains one essential β-barrel protein (BamA), one essential lipoprotein (BamD), and three non-essential lipoproteins (BamBCE). A gain-of-function mutation in bamA enables survival in the absence of BamD, showing that the essential function of this protein is regulatory. Here, we demonstrate that the global reduction in OMPs caused by BamD loss weakens the OM, altering cell shape and causing OM rupture in spent medium. To fill the void created by OMP loss, phospholipids (PLs) flip into the outer leaflet. Under these conditions, mechanisms that remove PLs from the outer leaflet create tension between the OM leaflets, which contributes to membrane rupture. Rupture is prevented by suppressor mutations that release the tension by halting PL removal from the outer leaflet. However, these suppressors do not restore OM stiffness or normal cell shape, revealing a possible connection between OM stiffness and cell shape.
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Affiliation(s)
- Irina V Mikheyeva
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA
| | - Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA.
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8
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Mohakud NK, Panda RK, Singh D, Patra SD, Simnani FZ, Sinha A, Nandi A, Jha E, Singh S, Kaushik NK, Panda PK, Singh D, Verma SK, Suar M. Intrinsic insights to antimicrobial effects of Nitrofurantoin to multi drug resistant Salmonella enterica serovar Typhimurium ms202. Biomed Pharmacother 2023; 165:115180. [PMID: 37454596 DOI: 10.1016/j.biopha.2023.115180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/05/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
Emerging multidrug resistant (MDR) serovar of Salmonella has raised the concern of their impactful effect on pathogenic infection and mortality in human lead by the enteric diseases. In order to combat the battle against these MDR Salmonella pathogen, new drug molecules need to be evaluated for their potent antibacterial application. This study evaluates the mechanistic antimicrobial effect of nitrofurantoin against a MDR strain of Salmonella named S. enterica Typhimurium ms202. The antimicrobial effect of nitrofurantoin was studied through experimental and computational approach using standard microbiological and molecular techniques like growth curve analysis, live-dead analysis, oxidative stress evaluation using high throughput techniques like flow cytometry and fluorescent microscopy. The result showed a potent dose dependent antibacterial effect of nitrofurantoin against S. enterica Typhimurium ms202 with a MIC value of 64 µg/ml. Moreover, the mechanistic excavation of the phenomenon described the mechanism as an effect of molecular interaction of nitrofurantoin molecule with membrane receptor proteins OmpC of S. enterica Typhimurium ms202 leading to internalization of the nitrofurantoin heading towards the occurrence of cellular physiological disturbances through oxidative stress impeded by nitrofurantoin-Sod1 C protein interaction. The results indicated towards a synergistic effect of membrane damage, oxidative stress and genotoxicity for the antibacterial effect of nitrofurantoin against S. enterica Typhimurium ms202. The study described the potent dose-dependent application of nitrofurantoin molecule against MDR strains of Salmonella and guided towards their use in further discovered MDR strains.
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Affiliation(s)
- Nirmal Kumar Mohakud
- Kalinga Institute of Medical Sciences (KIMS), KIIT University, Bhubaneswar 751024, India; School of Biotechnology, KIIT University, Bhubaneswar 751024, India
| | - Rakesh Kumar Panda
- Kalinga Institute of Medical Sciences (KIMS), KIIT University, Bhubaneswar 751024, India; SCB Medical College, Cuttack, India
| | | | | | | | - Adrija Sinha
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India
| | - Aditya Nandi
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India
| | - Ealisha Jha
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India
| | - Sarita Singh
- BVG Life Sciences Limited, Sagar Complex, Old Pune-Mumbai Road, Chinchwad, Pune 411034, India
| | - Nagendra Kumar Kaushik
- Plasma Bioscience Research Center, Department of Electrical and Biological Physics, Kwangwoon University, 01897 Seoul, South Korea
| | - Pritam Kumar Panda
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Deobrat Singh
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.
| | - Suresh K Verma
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India.
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India.
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9
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Liu DY, Phillips L, Wilson DM, Fulton KM, Twine SM, Wong A, Linington RG. Collateral sensitivity profiling in drug-resistant Escherichia coli identifies natural products suppressing cephalosporin resistance. Nat Commun 2023; 14:1976. [PMID: 37031190 PMCID: PMC10082850 DOI: 10.1038/s41467-023-37624-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/22/2023] [Indexed: 04/10/2023] Open
Abstract
The rapid emergence of antimicrobial resistance presents serious health challenges to the management of infectious diseases, a problem that is further exacerbated by slowing rates of antimicrobial drug discovery in recent years. The phenomenon of collateral sensitivity (CS), whereby resistance to one drug is accompanied by increased sensitivity to another, provides new opportunities to address both these challenges. Here, we present a high-throughput screening platform termed Collateral Sensitivity Profiling (CSP) to map the difference in bioactivity of large chemical libraries across 29 drug-resistant strains of E. coli. CSP screening of 80 commercial antimicrobials demonstrated multiple CS interactions. Further screening of a 6195-member natural product library revealed extensive CS relationships in nature. In particular, we report the isolation of known and new analogues of borrelidin A with potent CS activities against cephalosporin-resistant strains. Co-dosing ceftazidime with borrelidin A slows broader cephalosporin resistance with no recognizable resistance to borrelidin A itself.
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Affiliation(s)
- Dennis Y Liu
- Department of Chemistry, Simon Fraser University, 8888 University Dr., V5A 1S6, Burnaby, BC, Canada
| | - Laura Phillips
- Department of Biology, Carleton University, 1125 Colonel By Dr., K1S 5B6, Ottawa, ON, Canada
| | - Darryl M Wilson
- Department of Chemistry, Simon Fraser University, 8888 University Dr., V5A 1S6, Burnaby, BC, Canada
| | - Kelly M Fulton
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Dr., K1N 5A2, Ottawa, ON, Canada
| | - Susan M Twine
- Department of Biology, Carleton University, 1125 Colonel By Dr., K1S 5B6, Ottawa, ON, Canada
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Dr., K1N 5A2, Ottawa, ON, Canada
| | - Alex Wong
- Department of Biology, Carleton University, 1125 Colonel By Dr., K1S 5B6, Ottawa, ON, Canada
- Institute for Advancing Health Through Agriculture, Texas A&M AgriLife, 1500 Research Parkway, 77845, College Station, TX, USA
| | - Roger G Linington
- Department of Chemistry, Simon Fraser University, 8888 University Dr., V5A 1S6, Burnaby, BC, Canada.
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10
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Mikheyeva IV, Sun J, Huang KC, Silhavy TJ. Mechanism of outer membrane destabilization by global reduction of protein content. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.19.529137. [PMID: 36865163 PMCID: PMC9980000 DOI: 10.1101/2023.02.19.529137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The outer membrane (OM) of Gram-negative bacteria such as Escherichia coli is an asymmetric bilayer with the glycolipid lipopolysaccharide (LPS) in the outer leaflet and glycerophospholipids in the inner. Nearly all integral OM proteins (OMPs) have a characteristic β-barrel fold and are assembled in the OM by the BAM complex, which contains one essential β-barrel protein (BamA), one essential lipoprotein (BamD), and three non-essential lipoproteins (BamBCE). A gain-of-function mutation in bamA enables survival in the absence of BamD, showing that the essential function of this protein is regulatory. We demonstrate that the global reduction in OMPs caused by BamD loss weakens the OM, altering cell shape and causing OM rupture in spent medium. To fill the void created by OMP loss, PLs flip into the outer leaflet. Under these conditions, mechanisms that remove PLs from the outer leaflet create tension between the OM leaflets, which contributes to membrane rupture. Rupture is prevented by suppressor mutations that release the tension by halting PL removal from the outer leaflet. However, these suppressors do not restore OM stiffness or normal cell shape, revealing a possible connection between OM stiffness and cell shape. Significance Statement The outer membrane (OM) is a selective permeability barrier that contributes to the intrinsic antibiotic resistance of Gram-negative bacteria. Biophysical characterization of the roles of the component proteins, lipopolysaccharides, and phospholipids is limited by both the essentiality of the OM and its asymmetrical organization. In this study, we dramatically change OM physiology by limiting the protein content, which requires phospholipid localization to the outer leaflet and thus disrupts OM asymmetry. By characterizing the perturbed OM of various mutants, we provide novel insight into the links among OM composition, OM stiffness, and cell shape regulation. These findings deepen our understanding of bacterial cell envelope biology and provide a platform for further interrogation of OM properties.
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Affiliation(s)
- Irina V. Mikheyeva
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA
| | - Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Thomas J. Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA
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11
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Lai L, Yang J, Sun W, Su X, Chen J, Chen X, Pei S. Design, synthesis and antibacterial evaluation of a novel class of tetrahydrobenzothiophene derivatives. RSC Med Chem 2023; 14:166-172. [PMID: 36760738 PMCID: PMC9890943 DOI: 10.1039/d2md00373b] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/09/2022] [Indexed: 12/11/2022] Open
Abstract
In this study, a new series of tetrahydrobenzothiophene derivatives have been designed. Newly designed molecules have been synthesized through a medicinal chemistry route, and their characterization was done by using NMR and HR-MS techniques. Biological evaluation of the synthesized compounds has been done on Gram-negative and Gram-positive bacteria. The marketed antibiotics such as ciprofloxacin and gentamicin were used as controls. The in vitro evaluation results have shown that most of the targeted compounds exhibit good potency in inhibiting the growth of bacteria, including E. coli (MIC: 0.64-19.92 μM), P. aeruginosa (MIC: 0.72-45.30 μM), Salmonella (MIC: 0.54-90.58 μM) and S. aureus (MIC: 1.11-99.92 μM). In particular, compound 3b showed excellent activity with an MIC value of 1.11 μM against E. coli, 1.00 μM against P. aeruginosa, 0.54 μM against Salmonella, and 1.11 μM against S. aureus. From the results, a promising lead compound was identified for future development.
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Affiliation(s)
- Lin Lai
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
| | - Jinhua Yang
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
| | - Wanlin Sun
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
| | - Xiaoyan Su
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
| | - Jun Chen
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
| | - Xinan Chen
- German Institute of Engineering, Chongqing College of Mobile Communtion Chongqing 401520 China
| | - Shuchen Pei
- Key Laboratory of Industrial Fermentation Microorganism, Chongqing University of Science and Technology Chongqing 401331 China
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12
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Strategies for efficient extracellular secretion of recombinant cyclomaltodextrinase by Escherichia coli. FOOD BIOSCI 2022. [DOI: 10.1016/j.fbio.2022.102203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Butler D, Ambite I, Wan MLY, Tran TH, Wullt B, Svanborg C. Immunomodulation therapy offers new molecular strategies to treat UTI. Nat Rev Urol 2022; 19:419-437. [PMID: 35732832 PMCID: PMC9214477 DOI: 10.1038/s41585-022-00602-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2022] [Indexed: 12/13/2022]
Abstract
Innovative solutions are needed for the treatment of bacterial infections, and a range of antibacterial molecules have been explored as alternatives to antibiotics. A different approach is to investigate the immune system of the host for new ways of making the antibacterial defence more efficient. However, the immune system has a dual role as protector and cause of disease: in addition to being protective, increasing evidence shows that innate immune responses can become excessive and cause acute symptoms and tissue pathology during infection. This role of innate immunity in disease suggests that the immune system should be targeted therapeutically, to inhibit over-reactivity. The ultimate goal is to develop therapies that selectively attenuate destructive immune response cascades, while augmenting the protective antimicrobial defence but such treatment options have remained underexplored, owing to the molecular proximity of the protective and destructive effects of the immune response. The concept of innate immunomodulation therapy has been developed successfully in urinary tract infections, based on detailed studies of innate immune activation and disease pathogenesis. Effective, disease-specific, immunomodulatory strategies have been developed by targeting specific immune response regulators including key transcription factors. In acute pyelonephritis, targeting interferon regulatory factor 7 using small interfering RNA or treatment with antimicrobial peptide cathelicidin was protective and, in acute cystitis, targeting overactive effector molecules such as IL-1β, MMP7, COX2, cAMP and the pain-sensing receptor NK1R has been successful in vivo. Furthermore, other UTI treatment strategies, such as inhibiting bacterial adhesion and vaccination, have also shown promise. Hyperactivation of innate immunity is a disease determinant in urinary tract infections (UTIs). Modulation of innate immunity has promise as a therapy for UTIs. In this Review, the authors discuss potential mechanisms and immunomodulatory therapeutic strategies in UTIs. Excessive innate immune responses to infection cause symptoms and pathology in acute pyelonephritis and acute cystitis. Innate immunomodulation therapy is, therefore, a realistic option for treating these conditions. Targeting excessive innate immune responses at the level of transcription has been successful in animal models. Innate immunomodulation therapy reduces excessive inflammation and tissue pathology and accelerates bacterial clearance from infected kidneys and bladders in mice. Innate immunomodulation therapy also accelerates the clearance of antibiotic-resistant bacterial strains.
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Affiliation(s)
- Daniel Butler
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Ines Ambite
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Murphy Lam Yim Wan
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Thi Hien Tran
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Björn Wullt
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Catharina Svanborg
- Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, Sweden.
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14
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Phase separation in the outer membrane of Escherichia coli. Proc Natl Acad Sci U S A 2021; 118:2112237118. [PMID: 34716276 DOI: 10.1073/pnas.2112237118] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/20/2021] [Indexed: 11/18/2022] Open
Abstract
Gram-negative bacteria are surrounded by a protective outer membrane (OM) with phospholipids in its inner leaflet and lipopolysaccharides (LPS) in its outer leaflet. The OM is also populated with many β-barrel outer-membrane proteins (OMPs), some of which have been shown to cluster into supramolecular assemblies. However, it remains unknown how abundant OMPs are organized across the entire bacterial surface and how this relates to the lipids in the membrane. Here, we reveal how the OM is organized from molecular to cellular length scales, using atomic force microscopy to visualize the OM of live bacteria, including engineered Escherichia coli strains and complemented by specific labeling of abundant OMPs. We find that a predominant OMP in the E. coli OM, the porin OmpF, forms a near-static network across the surface, which is interspersed with barren patches of LPS that grow and merge with other patches during cell elongation. Embedded within the porin network is OmpA, which forms noncovalent interactions to the underlying cell wall. When the OM is destabilized by mislocalization of phospholipids to the outer leaflet, a new phase appears, correlating with bacterial sensitivity to harsh environments. We conclude that the OM is a mosaic of phase-separated LPS-rich and OMP-rich regions, the maintenance of which is essential to the integrity of the membrane and hence to the lifestyle of a gram-negative bacterium.
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15
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Patel H, Wu ZX, Chen Y, Bo L, Chen ZS. Drug resistance: from bacteria to cancer. MOLECULAR BIOMEDICINE 2021; 2:27. [PMID: 35006446 PMCID: PMC8607383 DOI: 10.1186/s43556-021-00041-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 04/22/2021] [Indexed: 12/14/2022] Open
Abstract
The phenomenon of drug resistance has been a hindrance to therapeutic medicine since the late 1940s. There is a plethora of factors and mechanisms contributing to progression of drug resistance. From prokaryotes to complex cancers, drug resistance is a prevailing issue in clinical medicine. Although there are numerous factors causing and influencing the phenomenon of drug resistance, cellular transporters contribute to a noticeable majority. Efflux transporters form a huge family of proteins and are found in a vast number of species spanning from prokaryotes to complex organisms such as humans. During the last couple of decades, various approaches in analyses of biochemistry and pharmacology of transporters have led us to understand much more about drug resistance. In this review, we have discussed the structure, function, potential causes, and mechanisms of multidrug resistance in bacteria as well as cancers.
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Affiliation(s)
- Harsh Patel
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Zhuo-Xun Wu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Yanglu Chen
- Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Letao Bo
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA.
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16
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Hu W, Wang Y, Yang B, Lin C, Yu H, Liu G, Deng Z, Ou HY, He X. Bacterial YedK represses plasmid DNA replication and transformation through its DNA single-strand binding activity. Microbiol Res 2021; 252:126852. [PMID: 34454309 DOI: 10.1016/j.micres.2021.126852] [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: 07/02/2021] [Revised: 07/30/2021] [Accepted: 08/21/2021] [Indexed: 10/20/2022]
Abstract
The SOS response-associated peptidase (SRAP) is an ancient protein superfamily in all domains of life. The mammalian SRAP was recently reported to covalently bind to the abasic sites (AP) in single stranded (ss) DNA to shield the chromosome integrity. YedK, the Escherichia coli SRAP, is not functionally characterized. Here we report the fortuitous pull-down of YedK from bacterial cell lysates by short (<20 bp) double stranded (ds) DNAs, further enrichment of YedK was observed when single stranded (ss) DNA was added. YedK can bind multiple DNA substrates, particularly with a high affinity to DNA duplex with single strand segment. As a SRAP protein, the involvement of YedK in SOS response was extensively examined, however yedK mutant of Escherichia coli showed no difference from the wild type strain upon the treatments with UV and various DNA damaging reagents, indicating its non-essentiality or redundancy in E. coli. Surprisingly, yedK mutants derived from Escherichia coli and Samonella enterica both showed an increased plasmid DNA transformation efficiency compared to the wild types. In accordance with this, induction of YedK effectively decreased the copy number of plasmid DNA. Site-directed mutagenesis of YedK demonstrated that residues involved in single strand DNA binding and cysteine residue at position 2 from N-terminus can discharge the repression of the plasmid transformation efficiency.
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Affiliation(s)
- Wenyue Hu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Yuli Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Bingxu Yang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Chen Lin
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Hao Yu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Guang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Hong-Yu Ou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Xinyi He
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
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17
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Yang EC, Hsieh YY, Chuang LY. Comparison of the Phytochemical Composition and Antibacterial Activities of the Various Extracts from Leaves and Twigs of Illicium verum. Molecules 2021; 26:molecules26133909. [PMID: 34206777 PMCID: PMC8272203 DOI: 10.3390/molecules26133909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 11/16/2022] Open
Abstract
Previous studies have revealed the numerous biological activities of the fruits of Illicium verum; however, the activities of its leaves and twigs have remained undiscovered. The study aimed to investigate the phytochemical components and antibacterial activity of the various extracts from the leaves and twigs of Illicium verum. The herbal extracts were prepared by supercritical CO2 extraction (SFE) and 95% ethanol extraction, followed by partition extraction based on solvent polarity. Analysis of antimicrobial activity was conducted through the usage of nine clinical antibiotic- resistant isolates, including Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. Among the tested samples, the SFE extracts exhibited broader and stronger antibacterial activities against the test strains, with a range of MIC between 0.1–4.0 mg/mL and MBC between 0.2–4.5 mg/mL. Observations made through scanning electron microscopy revealed potential mechanism of the antimicrobial activities involved disruption of membrane integrity of the test pathogens. Evaluation of the chemical composition by gas chromatography-mass spectrometry indicated the presence of anethole, anisyl aldehyde, anisyl acetone and anisyl alcohol within the SFE extracts, demonstrating significant correlations with the antibacterial activities observed. Therefore, the leaves and twigs of Illicium verum hold great potential in being developed as new natural antibacterial agents.
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Affiliation(s)
- Emirlyn-Cheng Yang
- Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong, China;
| | - Ya-Yun Hsieh
- Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan;
| | - Li-Yeh Chuang
- Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan;
- Department of Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan
- Correspondence:
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18
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Bishop RE. Phospholipid transporter shifts into reverse. Nat Struct Mol Biol 2020; 28:8-10. [PMID: 33361785 DOI: 10.1038/s41594-020-00546-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Russell E Bishop
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.
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19
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Lundstedt E, Kahne D, Ruiz N. Assembly and Maintenance of Lipids at the Bacterial Outer Membrane. Chem Rev 2020; 121:5098-5123. [PMID: 32955879 DOI: 10.1021/acs.chemrev.0c00587] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The outer membrane of Gram-negative bacteria is essential for their survival in harsh environments and provides intrinsic resistance to many antibiotics. This membrane is remarkable; it is a highly asymmetric lipid bilayer. The inner leaflet of the outer membrane contains phospholipids, whereas the fatty acyl chains attached to lipopolysaccharide (LPS) comprise the hydrophobic portion of the outer leaflet. This lipid asymmetry, and in particular the exclusion of phospholipids from the outer leaflet, is key to creating an almost impenetrable barrier to hydrophobic molecules that can otherwise pass through phospholipid bilayers. It has long been known that these lipids are not made in the outer membrane. It is now believed that conserved multisubunit protein machines extract these lipids after their synthesis is completed at the inner membrane and transport them to the outer membrane. A longstanding question is how the cell builds and maintains this asymmetric lipid bilayer in coordination with the assembly of the other components of the cell envelope. This Review describes the trans-envelope lipid transport systems that have been identified to participate in outer-membrane biogenesis: LPS transport via the Lpt machine, and phospholipid transport via the Mla pathway and several recently proposed transporters.
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Affiliation(s)
- Emily Lundstedt
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, United States
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20
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Soh SM, Jang H, Mitchell RJ. Loss of the lipopolysaccharide (LPS) inner core increases the electrocompetence of Escherichia coli. Appl Microbiol Biotechnol 2020; 104:7427-7435. [PMID: 32676713 DOI: 10.1007/s00253-020-10779-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/28/2020] [Accepted: 07/05/2020] [Indexed: 12/19/2022]
Abstract
Mutations that shorten the lipopolysaccharide (LPS) in Escherichia coli were found to significantly increase the number of transformants after electroporation. The loss of the LPS outer core increased the number of transformants with plasmid pAmCyan (3.3 kb) from 5.0 × 105 colony-forming units (CFU)/μg in the wild-type E. coli BW25113 to 3.3 × 107 CFU/μg in a ΔwaaG background, a 66.2-fold increase in efficiency. Truncation of the inner core improved this even further, with the ΔwaaF mutant exhibiting the best transformation efficiencies obtained, i.e., a 454.7-fold increase in the number of colonies over the wild-type strain. Similar results were obtained when a larger plasmid (pDA1; 11.3 kb) was used, with the ΔwaaF mutant once more giving the best transformation rates, i.e., a 73.7-fold increase. Subsequent tests proved that the enhanced transformabilities of these mutants were not due to a better survival or their surface charge properties, nor from preferential binding of these strains to the plasmid. Using N-phenyl-1-naphthylamine (NPN), we confirmed that the outer membranes of these mutant strains were more permeable. We also found that they leaked more ATP (3.4- and 2.0-fold higher for the ΔwaaF and ΔwaaG mutants, respectively, than wild-type E. coli BW25113), suggesting that the inner membrane stability is also reduced, helping to explain how the DNA enters these cells more easily. KEY POINTS: • LPS inner core gene knockouts increase the electrocompetence of E. coli. • No significant difference in survival, surface charge, or DNA binding was evident. • The LPS inner core mutants, however, exhibited higher outer membrane permeability. • Their inner membranes were also leaky, based on supernatant ATP concentrations.
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Affiliation(s)
- Sandrine M Soh
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Hyochan Jang
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Robert J Mitchell
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea.
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21
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Chen L, Liu C, Liu X, Wang GY. Phylogenetic analysis and screening of antimicrobial and cytotoxic activities of culturable bacteria associated with the ascidian Botryllus schlosseri. J Appl Microbiol 2020; 129:892-905. [PMID: 32311814 DOI: 10.1111/jam.14667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/25/2020] [Accepted: 04/12/2020] [Indexed: 11/26/2022]
Abstract
AIMS Isolating culturable bacteria associated with ascidian (Botryllus schlosseri) and investigating their bioactivities to discover new marine microbial resources with potential to produce novel bioactive natural products. METHODS AND RESULTS A total of 357 bacteria were isolated from the ascidian B. schlosseri from the coast of Weihai in the north Yellow Sea, China. Of these, 203 isolates were identified by 16S rRNA gene sequencing and they belonged to 52 genera from 30 families in five phyla. The antimicrobial activities and cytotoxic activities of all isolates were determined. Of the 357 isolates, 135 isolates demonstrated antimicrobial activities, and the crude extracts of five isolates showed strong cytotoxicity against human hepatocellular carcinoma Bel 7402 or human cervical carcinoma HeLa cells. CONCLUSIONS Our study revealed the diversity of bacteria associated with the ascidian B. schlosseri and reported a broad spectrum of antimicrobial and cytotoxic activities displayed by these isolates. SIGNIFICANCE AND IMPACT OF THE STUDY Our results suggest that the culturable bacteria associated with the ascidian B. schlosseri may be a potential source for novel bioactive compounds.
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Affiliation(s)
- L Chen
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
| | - C Liu
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
| | - X Liu
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
| | - G-Y Wang
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai, China
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22
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Genetic and Chemical-Genetic Interactions Map Biogenesis and Permeability Determinants of the Outer Membrane of Escherichia coli. mBio 2020; 11:mBio.00161-20. [PMID: 32156814 PMCID: PMC7064757 DOI: 10.1128/mbio.00161-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Gram-negative bacteria are intrinsically resistant to many antibiotics due to their outer membrane barrier. Although the outer membrane has been studied for decades, there is much to uncover about the biology and permeability of this complex structure. Investigating synthetic genetic interactions can reveal a great deal of information about genetic function and pathway interconnectivity. Here, we performed synthetic genetic arrays (SGAs) in Escherichia coli by crossing a subset of gene deletion strains implicated in outer membrane permeability with nonessential gene and small RNA (sRNA) deletion collections. Some 155,400 double-deletion strains were grown on rich microbiological medium with and without subinhibitory concentrations of two antibiotics excluded by the outer membrane, vancomycin and rifampin, to probe both genetic interactions and permeability. The genetic interactions of interest were synthetic sick or lethal (SSL) gene deletions that were detrimental to the cell in combination but had a negligible impact on viability individually. On average, there were ∼30, ∼36, and ∼40 SSL interactions per gene under no-drug, rifampin, and vancomycin conditions, respectively; however, many of these involved frequent interactors. Our data sets have been compiled into an interactive database called the Outer Membrane Interaction (OMI) Explorer, where genetic interactions can be searched, visualized across the genome, compared between conditions, and enriched for gene ontology (GO) terms. A set of SSL interactions revealed connectivity and permeability links between enterobacterial common antigen (ECA) and lipopolysaccharide (LPS) of the outer membrane. This data set provides a novel platform to generate hypotheses about outer membrane biology and permeability.IMPORTANCE Gram-negative bacteria are a major concern for public health, particularly due to the rise of antibiotic resistance. It is important to understand the biology and permeability of the outer membrane of these bacteria in order to increase the efficacy of antibiotics that have difficulty penetrating this structure. Here, we studied the genetic interactions of a subset of outer membrane-related gene deletions in the model Gram-negative bacterium E. coli We systematically combined these mutants with 3,985 nonessential gene and small RNA deletion mutations in the genome. We examined the viability of these double-deletion strains and probed their permeability characteristics using two antibiotics that have difficulty crossing the outer membrane barrier. An understanding of the genetic basis for outer membrane integrity can assist in the development of new antibiotics with favorable permeability properties and the discovery of compounds capable of increasing outer membrane permeability to enhance the activity of existing antibiotics.
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23
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran.,Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran.,Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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de la Calle ME, Cabrera G, Cantero D, Valle A, Bolivar J. A genetically engineered Escherichia coli strain overexpressing the nitroreductase NfsB is capable of producing the herbicide D-DIBOA with 100% molar yield. Microb Cell Fact 2019; 18:86. [PMID: 31109333 PMCID: PMC6526606 DOI: 10.1186/s12934-019-1135-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/08/2019] [Indexed: 11/10/2022] Open
Abstract
Background The use of chemical herbicides has helped to improve agricultural production, although its intensive use has led to environmental damages. Plant allelochemicals are interesting alternatives due to their diversity and degradability in the environment. However, the main drawback of this option is their low natural production, which could be overcome by its chemical synthesis. In the case of the allelochemical DIBOA ((2,4-dihydroxy-2H)-1,4-benzoxazin-3(4H)-one), the synthesis of the analogous compound D-DIBOA (2-deoxy-DIBOA) has been achieved in two steps. However, the scale up of this synthesis is hindered by the second step, which uses an expensive catalyst and is an exothermic reaction, with hydrogen release and a relatively low molar yield (70%). We have previously explored the “Green Chemistry” alternative of using E. coli strains overexpressing the nitroreductase NfsB as a whole-cell-biocatalyst to replace this second step, although the molar yield in this case was lower than that of the chemical synthesis. Results In this work, we engineered an E. coli strain capable of carrying out this reaction with 100% molar yield and reaching a D-DIBOA concentration up to 379% respect to the highest biotransformation yield previously reported. This was achieved by a screening of 34 E. coli mutant strains in order to improve D-DIBOA production that led to the construction of the ΔlapAΔfliQ double mutant as an optimum genetic background for overexpression of the NfsB enzyme and D-DIBOA synthesis. Also, the use of a defined medium instead of a complex one, the optimization of the culture conditions and the development of processes with several substrate loads allowed obtaining maxima yields and concentrations. Conclusions The high yields and concentrations of D-DIBOA reached by the microbial-cell-factory approach developed in this work will facilitate its application to industrial scale. Also, the use of an optimized defined medium with only an organic molecule (glucose as carbon and energy source) in its composition will also facilitate the downstream processes. Electronic supplementary material The online version of this article (10.1186/s12934-019-1135-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria Elena de la Calle
- Department of Chemical Engineering and Food Technology, University of Cadiz, Campus Universitario de Puerto Real, Puerto Real, 11510, Cadiz, Spain.,Institute of Viticulture and Agri-Food Research (IVAGRO)-International Campus of Excellence (ceiA3), University of Cadiz, Puerto Real, Spain
| | - Gema Cabrera
- Department of Chemical Engineering and Food Technology, University of Cadiz, Campus Universitario de Puerto Real, Puerto Real, 11510, Cadiz, Spain.,Institute of Viticulture and Agri-Food Research (IVAGRO)-International Campus of Excellence (ceiA3), University of Cadiz, Puerto Real, Spain
| | - Domingo Cantero
- Department of Chemical Engineering and Food Technology, University of Cadiz, Campus Universitario de Puerto Real, Puerto Real, 11510, Cadiz, Spain.,Institute of Viticulture and Agri-Food Research (IVAGRO)-International Campus of Excellence (ceiA3), University of Cadiz, Puerto Real, Spain
| | - Antonio Valle
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, University of Cadiz, Campus Universitario de Puerto Real, Puerto Real, 11510, Cadiz, Spain. .,Institute of Viticulture and Agri-Food Research (IVAGRO)-International Campus of Excellence (ceiA3), University of Cadiz, Puerto Real, Spain.
| | - Jorge Bolivar
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, University of Cadiz, Campus Universitario de Puerto Real, Puerto Real, 11510, Cadiz, Spain. .,Institute of Biomolecules (INBIO), University of Cadiz, Puerto Real, Spain.
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Kahler CM, Sarkar-Tyson M, Kibble EA, Stubbs KA, Vrielink A. Enzyme targets for drug design of new anti-virulence therapeutics. Curr Opin Struct Biol 2018; 53:140-150. [PMID: 30223251 DOI: 10.1016/j.sbi.2018.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 08/30/2018] [Accepted: 08/30/2018] [Indexed: 12/19/2022]
Abstract
Society has benefitted greatly from the use of antibiotics. Unfortunately, the misuse of these valuable molecules has resulted in increased levels of antibiotic resistance, a major global and public health issue. This resistance and the reliance on a small number of biological targets for the development of antibiotics emphasizes the need for new targets. A critical aspect guiding the development of new antimicrobials through a rational structure-guided approach is to understand the molecular structures of specific biological targets of interest. Here we give an overview of the structures of bacterial virulence enzyme targets involved in protein folding, peptidoglycan biosynthesis and cell wall modification. These include enzymes of the thiol-disulphide oxidoreductase pathway (DSB enzymes), peptidyl-proly cis/trans isomerases (Mips), enzymes from the Mur pathway and enzymes involved in lipopolysaccharide modification (EptA and ArnT). We also present progress towards inhibitor design of these targets for the development of novel anti-virulence therapeutic agents.
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Affiliation(s)
- Charlene M Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Emily A Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Keith A Stubbs
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Alice Vrielink
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia; Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
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26
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Synthesis, interfacial properties, and antimicrobial activity of a new cationic gemini surfactant. KOREAN J CHEM ENG 2018. [DOI: 10.1007/s11814-018-0133-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Ebbensgaard A, Mordhorst H, Aarestrup FM, Hansen EB. The Role of Outer Membrane Proteins and Lipopolysaccharides for the Sensitivity of Escherichia coli to Antimicrobial Peptides. Front Microbiol 2018; 9:2153. [PMID: 30245684 PMCID: PMC6137088 DOI: 10.3389/fmicb.2018.02153] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/22/2018] [Indexed: 01/20/2023] Open
Abstract
Bacterial resistance to classical antibiotics is emerging worldwide. The number of infections caused by multidrug resistant bacteria is increasing and becoming a serious threat for human health globally. In particular, Gram-negative pathogens including multidrug resistant Escherichia coli are of serious concern being resistant to the currently available antibiotics. All Gram-negative bacteria are enclosed by an outer membrane which acts as an additional protection barrier preventing the entry of toxic compounds including antibiotics and antimicrobial peptides (AMPs). In this study we report that the outer membrane component lipopolysaccharide (LPS) plays a crucial role for the antimicrobial susceptibility of E. coli BW25113 against the cationic AMPs Cap18, Cap11, Cap11-1-18m2, melittin, indolicidin, cecropin P1, cecropin B, and the polypeptide antibiotic colistin, whereas the outer membrane protease OmpT and the lipoprotein Lpp only play a minor role for the susceptibility against cationic AMPs. Increased susceptibility toward cationic AMPs was found for LPS deficient mutants of E. coli BW25113 harboring deletions in any of the genes required for the inner part of core-oligosaccharide of the LPS, waaC, waaE, waaF, waaG, and gmhA. In addition, our study demonstrates that the antimicrobial activity of Cap18, Cap11, Cap11-1-18m2, cecropin B, and cecropin P1 is not only dependent on the inner part of the core oligosaccharide, but also on the outer part and its sugar composition. Finally, we demonstrated that the antimicrobial activity of selected Cap18 derivatives harboring amino acid substitutions in the hydrophobic interface, are non-active against wild-type E. coli ATCC29522. By deleting waaC, waaE, waaF, or waaG the antimicrobial activity of the non-active derivatives can be partially or fully restored, suggesting a very close interplay between the LPS core oligosaccharide and the specific Cap18 derivative. Summarizing, this study implicates that the nature of the outer membrane component LPS has a big impact on the antimicrobial activity of cationic AMPs against E. coli. In particular, the inner as well as the outer part of the core oligosaccharide are important elements determining the antimicrobial susceptibility of E. coli against cationic AMPs.
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Affiliation(s)
- Anna Ebbensgaard
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark.,Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Hanne Mordhorst
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Frank M Aarestrup
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Egon B Hansen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
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Cell-based screen for discovering lipopolysaccharide biogenesis inhibitors. Proc Natl Acad Sci U S A 2018; 115:6834-6839. [PMID: 29735709 DOI: 10.1073/pnas.1804670115] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
New drugs are needed to treat gram-negative bacterial infections. These bacteria are protected by an outer membrane which prevents many antibiotics from reaching their cellular targets. The outer leaflet of the outer membrane contains LPS, which is responsible for creating this permeability barrier. Interfering with LPS biogenesis affects bacterial viability. We developed a cell-based screen that identifies inhibitors of LPS biosynthesis and transport by exploiting the nonessentiality of this pathway in Acinetobacter We used this screen to find an inhibitor of MsbA, an ATP-dependent flippase that translocates LPS across the inner membrane. Treatment with the inhibitor caused mislocalization of LPS to the cell interior. The discovery of an MsbA inhibitor, which is universally conserved in all gram-negative bacteria, validates MsbA as an antibacterial target. Because our cell-based screen reports on the function of the entire LPS biogenesis pathway, it could be used to identify compounds that inhibit other targets in the pathway, which can provide insights into vulnerabilities of the gram-negative cell envelope.
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30
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Mutation and Suppressor Analysis of the Essential Lipopolysaccharide Transport Protein LptA Reveals Strategies To Overcome Severe Outer Membrane Permeability Defects in Escherichia coli. J Bacteriol 2017; 200:JB.00487-17. [PMID: 29109183 DOI: 10.1128/jb.00487-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/26/2017] [Indexed: 11/20/2022] Open
Abstract
In Gram-negative bacteria, lipopolysaccharide (LPS) contributes to the robust permeability barrier of the outer membrane (OM), preventing the entry of toxic molecules, such as detergents and antibiotics. LPS is transported from the inner membrane (IM) to the OM by the Lpt multiprotein machinery. Defects in LPS transport compromise LPS assembly at the OM and result in increased antibiotic sensitivity. LptA is a key component of the Lpt machine that interacts with the IM protein LptC and chaperones LPS through the periplasm. We report here the construction of lptA41, a quadruple mutant in four conserved amino acids potentially involved in LPS or LptC binding. Although viable, the mutant displays increased sensitivity to several antibiotics (bacitracin, rifampin, and novobiocin) and the detergent SDS, suggesting that lptA41 affects LPS transport. Indeed, lptA41 is defective in Lpt complex assembly, and its lipid A carries modifications diagnostic of LPS transport defects. We also selected and characterized two phenotypic bacitracin-resistant suppressors of lptA41 One mutant, in which only bacitracin sensitivity is suppressed, harbors a small in-frame deletion in mlaA, which codes for an OM lipoprotein involved in maintaining OM asymmetry by reducing accumulation of phospholipids in the outer leaflet. The other mutant, in which bacitracin, rifampin, and SDS sensitivity is suppressed, harbors an additional amino acid substitution in LptA41 and a nonsense mutation in opgH, encoding a glycosyltransferase involved in periplasmic membrane-derived oligosaccharide synthesis. Characterization of the suppressor mutants highlights different strategies adopted by the cell to overcome OM defects caused by impaired LPS transport.IMPORTANCE Lipopolysaccharide (LPS) is the major constituent of the outer membrane (OM) of most Gram-negative bacteria, forming a barrier against antibiotics. LPS is synthesized at the inner membrane (IM), transported across the periplasm, and assembled at the OM by the multiprotein Lpt complex. LptA is the periplasmic component of the Lpt complex, which bridges IM and OM and ferries LPS across the periplasm. How the cell coordinates the processes involved in OM biogenesis is not completely understood. We generated a mutant partially defective in lptA that exhibited increased sensitivity to antibiotics and selected for suppressors of the mutant. The analysis of two independent suppressors revealed different strategies adopted by the cell to overcome defects in LPS biogenesis.
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Weinkauf H, Brehm-Stecher B. Sodium Polyphosphate and Polyethylenimine Enhance the Antimicrobial Activities of Plant Essential Oils. SCIENCEOPEN RESEARCH 2016. [DOI: 10.14293/s2199-1006.1.sor-life.z72tp0.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
<p>Plant extracts have been used for millennia for treatment of disease, with much recent interest focusing on the antimicrobial activities of plant essential oils (EOs). Although EOs are active against common microbial pathogens, their effective use as topical, environmental or food antimicrobials will require EO-based formulations with enhanced antimicrobial activities. In the present study, two polyionic compounds, sodium polyphosphate (polyP, a polyanion) and polyethylenimine (PEI, a polycation), were evaluated for their abilities to enhance the antimicrobial activities of six EOs against the human pathogens <em>Escherichia coli</em> O157:H7, <em>Salmonella enterica</em> subsp. <em>enterica </em>ser Minnesota, <em>Pseudomonas aeruginosa</em>, <em>Listeria monocytogenes</em>, <em>Staphylococcus aureus </em>and <em>Candida albicans</em>. EOs tested were cinnamon, clove, regular and redistilled oregano and two types of thyme oil. EOs were examined via disk diffusion and broth microdilution, either alone or in the presence of sub-inhibitory levels of polyP or PEI. Both polyP and PEI were found to be effective enhancers of EO activity against all strains examined, and calculation of fractional inhibitory indices for select EO/organism pairings demonstrated that true synergy was possible with this enhancement approach. Experiments with a deep rough strain of S. Minnesota probed the role of the outer membrane in both intrinsic resistance to EOs and enhancement by polyions. The use of polyP and PEI for boosting the antimicrobial activities of EOs may eventually facilitate the development of more effective EO-based antimicrobial treatments for use in applications such as wound treatment, surface disinfection, or as GRAS antimicrobials for use in foods or on food contact surfaces.</p>
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Chong H, Ching CB. Development of Colorimetric-Based Whole-Cell Biosensor for Organophosphorus Compounds by Engineering Transcription Regulator DmpR. ACS Synth Biol 2016; 5:1290-1298. [PMID: 27346389 DOI: 10.1021/acssynbio.6b00061] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
It is useful for whole-cell biosensors to be based on colorimetric detection because the output signal can be easily visualized. However, colorimetric-based whole-cell biosensors suffer higher detection limits as compared to bioluminescence- or fluorescence-based biosensors. In this work, we attempt to reduce the detection limit for a colorimetric-based whole-cell biosensor by applying directed evolution techniques on a transcription regulator, DmpR, to alter the expression level of its cognate promoter, which was fused to mRFP1 to output red coloration in the presence of organophosphate pesticides containing a phenolic group. We selected the two best-performing mutants, DM01 and DM12, which were able to develop red coloration in the presence of parathion as low as 10 μM after just 6 h of induction at 30 °C. This suggests that engineering of the transcription regulator in the sensing domain is useful for improving various properties of whole-cell biosensors, such as reducing the detection limit for simple colorimetric detection of organophosphate pesticides.
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Affiliation(s)
- Huiqing Chong
- Temasek Laboratories, National University of Singapore 117411, Singapore
| | - Chi Bun Ching
- Temasek Laboratories, National University of Singapore 117411, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore 117585, Singapore
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33
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Gomes C, Martínez-Puchol S, Palma N, Horna G, Ruiz-Roldán L, Pons MJ, Ruiz J. Macrolide resistance mechanisms in Enterobacteriaceae: Focus on azithromycin. Crit Rev Microbiol 2016; 43:1-30. [DOI: 10.3109/1040841x.2015.1136261] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Cláudia Gomes
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic ? Universitat de Barcelona, Spain
| | - Sandra Martínez-Puchol
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic ? Universitat de Barcelona, Spain
| | - Noemí Palma
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic ? Universitat de Barcelona, Spain
| | - Gertrudis Horna
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic ? Universitat de Barcelona, Spain
- Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Maria J Pons
- Universidad Peruana de Ciencias Aplicadas, Lima, Peru
| | - Joaquim Ruiz
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic ? Universitat de Barcelona, Spain
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Hsu PC, Jefferies D, Khalid S. Molecular Dynamics Simulations Predict the Pathways via Which Pristine Fullerenes Penetrate Bacterial Membranes. J Phys Chem B 2016; 120:11170-11179. [DOI: 10.1021/acs.jpcb.6b06615] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pin-Chia Hsu
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Damien Jefferies
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
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35
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Nobre TM, Martynowycz MW, Andreev K, Kuzmenko I, Nikaido H, Gidalevitz D. Modification of Salmonella Lipopolysaccharides Prevents the Outer Membrane Penetration of Novobiocin. Biophys J 2016; 109:2537-2545. [PMID: 26682812 DOI: 10.1016/j.bpj.2015.10.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/23/2015] [Accepted: 10/08/2015] [Indexed: 11/29/2022] Open
Abstract
Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate lipopolysaccharides from isogenic mutants of Salmonella sp., one lacking the modification, the other fully modified. These lipopolysaccharides were reconstituted as monolayers at the air-water interface, and their properties, as well as their interaction with a large lipophilic drug, novobiocin, was studied. X-ray reflectivity showed that the drug penetrated the monolayer of the unmodified lipopolysaccharides reaching the hydrophobic region, but was prevented from this penetration into the modified lipopolysaccharides. Results correlate with behavior of bacterial cells, which become resistant to antibiotics after PhoPQ-regulated modifications. Grazing incidence x-ray diffraction showed that novobiocin produced a striking increase in crystalline coherence length, and the size of the near-crystalline domains.
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Affiliation(s)
- Thatyane M Nobre
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California; Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California.
| | - Michael W Martynowycz
- Center for Molecular Study of Condensed Soft Matter and Department of Physics, Illinois Institute of Technology, Chicago, Illinois; X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois
| | - Konstantin Andreev
- Center for Molecular Study of Condensed Soft Matter and Department of Physics, Illinois Institute of Technology, Chicago, Illinois
| | - Ivan Kuzmenko
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California
| | - David Gidalevitz
- Center for Molecular Study of Condensed Soft Matter and Department of Physics, Illinois Institute of Technology, Chicago, Illinois.
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Trent MS, Stead CM, Tran AX, Hankins JV. Invited review: Diversity of endotoxin and its impact on pathogenesis. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120040201] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipopolysaccharide or LPS is localized to the outer leaflet of the outer membrane and serves as the major surface component of the bacterial cell envelope. This remarkable glycolipid is essential for virtually all Gram-negative organisms and represents one of the conserved microbial structures responsible for activation of the innate immune system. For these reasons, the structure, function, and biosynthesis of LPS has been an area of intense research. The LPS of a number of bacteria is composed of three distinct regions — lipid A, a short core oligosaccharide, and the O-antigen polysaccharide. The lipid A domain, also known as endotoxin, anchors the molecule in the outer membrane and is the bioactive component recognized by TLR4 during human infection. Overall, the biochemical synthesis of lipid A is a highly conserved process; however, investigation of the lipid A structures of various organisms shows an impressive amount of diversity. These differences can be attributed to the action of latent enzymes that modify the canonical lipid A molecule. Variation of the lipid A domain of LPS serves as one strategy utilized by Gram-negative bacteria to promote survival by providing resistance to components of the innate immune system and helping to evade recognition by TLR4. This review summarizes the biochemical machinery required for the production of diverse lipid A structures of human pathogens and how structural modification of endotoxin impacts pathogenesis.
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Affiliation(s)
- M. Stephen Trent
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA,
| | - Christopher M. Stead
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - An X. Tran
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Jessica V. Hankins
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
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Gronow S, Brade H. Invited review: Lipopolysaccharide biosynthesis: which steps do bacteria need to survive? ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519010070010301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A detailed knowledge of LPS biosynthesis is of the utmost importance in understanding the function of the outer membrane of Gram-negative bacteria. The regulation of LPS biosynthesis affects many more compartments of the bacterial cell than the outer membrane and thus contributes to the understanding of the physiology of Gram-negative bacteria in general, on the basis of which only mechanisms of virulence and antibiotic resistance can be studied to find new targets for antibacterial treatment. The study of LPS biosynthesis is also an excellent example to demonstrate the limitations of `genomics' and `proteomics', since secondary gene products can be studied only by the combined tools of molecular genetics, enzymology and analytical structural biochemistry. Thus, the door to the field of `glycomics' is opened.
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Affiliation(s)
- Sabine Gronow
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany,
| | - Helmut Brade
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
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A Transposon Screen Identifies Genetic Determinants of Vibrio cholerae Resistance to High-Molecular-Weight Antibiotics. Antimicrob Agents Chemother 2016; 60:4757-63. [PMID: 27216069 DOI: 10.1128/aac.00576-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/19/2016] [Indexed: 12/22/2022] Open
Abstract
Gram-negative bacteria are notoriously resistant to a variety of high-molecular-weight antibiotics due to the limited permeability of their outer membrane (OM). The basis of OM barrier function and the genetic factors required for its maintenance remain incompletely understood. Here, we employed transposon insertion sequencing to identify genes required for Vibrio cholerae resistance to vancomycin and bacitracin, antibiotics that are thought to be too large to efficiently penetrate the OM. The screen yielded several genes whose protein products are predicted to participate in processes important for OM barrier functions and for biofilm formation. In addition, we identified a novel factor, designated vigA (for vancomycin inhibits growth), that has not previously been characterized or linked to outer membrane function. The vigA open reading frame (ORF) codes for an inner membrane protein, and in its absence, cells became highly sensitive to glycopeptide antibiotics (vancomycin and ramoplanin) and bacitracin but not to other large antibiotics or detergents. In contrast to wild-type (WT) cells, the vigA mutant was stained with fluorescent vancomycin. These observations suggest that VigA specifically prevents the periplasmic accumulation of certain large antibiotics without exerting a general role in the maintenance of OM integrity. We also observed marked interspecies variability in the susceptibilities of Gram-negative pathogens to glycopeptides and bacitracin. Collectively, our findings suggest that the OM barrier is not absolute but rather depends on specific OM-antibiotic interactions.
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Canli K, Akata I, Altuner EM. IN VITRO ANTIMICROBIAL ACTIVITY SCREENING OF XYLARIA HYPOXYLON. AFRICAN JOURNAL OF TRADITIONAL, COMPLEMENTARY, AND ALTERNATIVE MEDICINES : AJTCAM 2016; 13:42-46. [PMID: 28852719 PMCID: PMC5566152 DOI: 10.21010/ajtcam.v13i4.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Fungi have a potential of using both as nutritive and medicinal food stuff. Because of containing several therapeutic agents, they are reported to be used for hundreds of years to treat several diseases caused by bacteria, fungi, viruses and parasites. The aim of this study is to determine the in vitro antimicrobial activity of Xylaria hypoxylon, which were collected from Yomra, Trabzon, Turkey. MATERIALS AND METHODS X. hypoxylon samples were air dried and extracted by using ethanol. Antimicrobial activity of X. hypoxylon ethanol extracts were investigated against 21 bacterial and 2 fungal strains, namely, Bacillus subtilis DSMZ 1971, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231, Candida albicans DSMZ 1386, Enterobacter aerogenes ATCC 13048, Enterococcus durans, Enterococcus faecalis ATCC 29212, Enterococcus faecium, Escherichia coli ATCC 25922, Escherichia coli CFAI, Klebsiella pneumoniae, Listeria innocula, Listeria monocytogenes ATCC 7644, Pseudomonas aeruginosa DSMZ 50071, Pseudomonas fluorescence P1, Salmonella enteritidis ATCC 13075, Salmonella infantis, Salmonella kentucky, Salmonella typhimurium SL 1344, Staphylococcus aureus ATCC 25923, Staphylococcus carnosus MC1.B, Staphylococcus epidermidis DSMZ 20044 and Streptococcus agalactiae DSMZ 6784 by using the disk diffusion method. RESULTS It is observed that ethanol extracts of X. hypoxylon has antimicrobial activity against several Gram positive and Gram negative microorganisms tested. As a result of the study, an antimicrobial activity of X. hypoxylon found against most of strains used in the study. CONCLUSION The results of our study clearly puts forward that X. hypoxylon could have a possible medicinal use.
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Affiliation(s)
- Kerem Canli
- Dokuz Eylül University, Faculty of Science, Department of Biology, Buca, İzmir, TURKEY
| | - Ilgaz Akata
- Ankara University, Faculty of Science, Department of Biology, TR 06100, Ankara, TURKEY
| | - Ergin Murat Altuner
- Kastamonu University, Faculty of Science and Arts, Department of Biology, TR 37150, Kastamonu, TURKEY
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Kowata H, Tochigi S, Kusano T, Kojima S. Quantitative measurement of the outer membrane permeability in Escherichia coli lpp and tol-pal mutants defines the significance of Tol-Pal function for maintaining drug resistance. J Antibiot (Tokyo) 2016; 69:863-870. [PMID: 27168313 DOI: 10.1038/ja.2016.50] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/16/2016] [Accepted: 04/05/2016] [Indexed: 02/05/2023]
Abstract
Ensuring the stability of the outer membrane permeability barrier is crucial for maintaining drug resistance in Gram-negative bacteria. Lpp protein and Tol-Pal complex are responsible for this function and are widely distributed among Gram-negative bacteria. Thus, these proteins are potential targets to permeabilize the outer membrane barrier. Although deleting these proteins is known to impair the outer membrane stability, the effect of the deletion on the outer membrane barrier property and on the drug resistance has not been fully characterized and evaluated in a quantitative manner. Here, we determined the outer membrane permeability of Escherichia coli Δlpp and Δtol-pal mutants by the assay using intact cells and liposomes reconstituted with the outer membrane proteins. We determined that there was 3- to 5-fold increase of the permeability in Δtol-pal mutants, but not in Δlpp mutant, compared with that in the parental strain. The permeability increase in Δtol-pal mutants occurred without affecting the function of outer membrane diffusion channels, and was most pronounced in the cells at exponential growth phase. The impact of tol-pal deletion on the drug resistance was revealed to be almost comparable with that of deletion of acrAB, a major multidrug efflux transporter of E. coli that makes a predominant contribution to drug resistance. Our observations highlight the importance of Tol-Pal as a possible target to combat multidrug-resistant Gram-negative bacteria.
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Affiliation(s)
- Hikaru Kowata
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Saeko Tochigi
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Tomonobu Kusano
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Seiji Kojima
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
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Metabolic Fingerprinting of Pseudomonas putida DOT-T1E Strains: Understanding the Influence of Divalent Cations in Adaptation Mechanisms Following Exposure to Toluene. Metabolites 2016; 6:metabo6020014. [PMID: 27128955 PMCID: PMC4931545 DOI: 10.3390/metabo6020014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas putida strains can adapt and overcome the activity of toxic organic solvents by the employment of several resistant mechanisms including efflux pumps and modification to lipopolysaccharides (LPS) in their membranes. Divalent cations such as magnesium and calcium play a crucial role in the development of solvent tolerance in bacterial cells. Here, we have used Fourier transform infrared (FT-IR) spectroscopy directly on cells (metabolic fingerprinting) to monitor bacterial response to the absence and presence of toluene, along with the influence of divalent cations present in the growth media. Multivariate analysis of the data using principal component-discriminant function analysis (PC-DFA) showed trends in scores plots, illustrating phenotypic alterations related to the effect of Mg(2+), Ca(2+) and toluene on cultures. Inspection of PC-DFA loadings plots revealed that several IR spectral regions including lipids, proteins and polysaccharides contribute to the separation in PC-DFA space, thereby indicating large phenotypic response to toluene and these cations. Finally, the saturated fatty acid ratio from the FT-IR spectra showed that upon toluene exposure, the saturated fatty acid ratio was reduced, while it increased in the presence of divalent cations. This study clearly demonstrates that the combination of metabolic fingerprinting with appropriate chemometric analysis can result in practicable knowledge on the responses of important environmental bacteria to external stress from pollutants such as highly toxic organic solvents, and indicates that these changes are manifest in the bacterial cell membrane. Finally, we demonstrate that divalent cations improve solvent tolerance in P. putida DOT‑T1E strains.
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Antimicrobial Activity of Some Novel Armed Thiophene Derivatives and Petra/Osiris/Molinspiration (POM) Analyses. Molecules 2016; 21:molecules21020222. [PMID: 26901173 PMCID: PMC6273311 DOI: 10.3390/molecules21020222] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 11/16/2022] Open
Abstract
Tetrasubstituted 2-acetylthiophene derivative 5 was synthesized and then condensed with various nitrogen nucleophiles such as 5-amino-1,2,4-triazole, 2-aminobenzimidazole, aniline or p-chloroaniline to afford the corresponding iminothiophene derivatives 6-8a,b. Condensation of thiophene 5 with malononitrile as carbon nucleophile afforded compound 9, which underwent nucleophilic addition with DMF-DMA to afford compound 10. The newly synthesized products were characterized by elemental analysis, IR, MS, ¹H-(13)C-NMR and CHN analysis and then evaluated for their antimicrobial activity. Results of the in vitro antibacterial activity showed that thiophene derivative 7 was found to be more potent than the standard drug gentamicin against Pseudomonas aeruginosa. Some of these compounds showed potential antimicrobial activities. Molecular docking and Osiris/Molinspiration analyses show the crucial role and impact of substituents on bioactivity and indicate the unfavorable structural parameters in actual drug design: more substitution with electronic donor group doesn't guarantee more effective bioactivity. This study should greatly help in an intelligent and a controlled pharmacomodulation of antibiotics.
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Bruckner S, Bilitewski U, Schobert R. Synthesis and Antibacterial Activity of Four Stereoisomers of the Spider-Pathogenic Fungus Metabolite Torrubiellone D. Org Lett 2016; 18:1136-9. [PMID: 26871963 DOI: 10.1021/acs.orglett.6b00245] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sebastian Bruckner
- Organic
Chemistry Laboratory, University Bayreuth, Universitaetsstrasse 30, 95440 Bayreuth, Germany
| | - Ursula Bilitewski
- Helmholtz Centre
for Infection Research, Inhoffenstrasse
7, 38124 Braunschweig, Germany
| | - Rainer Schobert
- Organic
Chemistry Laboratory, University Bayreuth, Universitaetsstrasse 30, 95440 Bayreuth, Germany
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The influence of rough lipopolysaccharide structure on molecular interactions with mammalian antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:197-209. [DOI: 10.1016/j.bbamem.2015.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/03/2015] [Accepted: 11/12/2015] [Indexed: 11/21/2022]
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Cold Stress Makes Escherichia coli Susceptible to Glycopeptide Antibiotics by Altering Outer Membrane Integrity. Cell Chem Biol 2016; 23:267-277. [DOI: 10.1016/j.chembiol.2015.12.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/02/2015] [Accepted: 12/22/2015] [Indexed: 11/20/2022]
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Antimicrobial Activities of Methanol, Ethanol and Supercritical CO2 Extracts of Philippine Piper betle L. on Clinical Isolates of Gram Positive and Gram Negative Bacteria with Transferable Multiple Drug Resistance. PLoS One 2016; 11:e0146349. [PMID: 26741962 PMCID: PMC4704777 DOI: 10.1371/journal.pone.0146349] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/10/2015] [Indexed: 11/20/2022] Open
Abstract
Piper betle L. has traditionally been used in alternative medicine in different countries for various therapeutic purposes, including as an anti-infective agent. However, studies reported in the literature are mainly on its activities on drug susceptible bacterial strains. This study determined the antimicrobial activities of its ethanol, methanol, and supercritical CO2 extracts on clinical isolates of multiple drug resistant bacteria which have been identified by the Infectious Disease Society of America as among the currently more challenging strains in clinical management. Assay methods included the standard disc diffusion method and the broth microdilution method for the determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) of the extracts for the test microorganisms. This study revealed the bactericidal activities of all the P. betle leaf crude extracts on methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii, with minimum bactericidal concentrations that ranged from 19μg/ml to 1250 μg/ml. The extracts proved to be more potent against the Gram positive MRSA and VRE than for the Gram negative test bacteria. VRE isolates were more susceptible to all the extracts than the MRSA isolates. Generally, the ethanol extracts proved to be more potent than the methanol extracts and supercritical CO2 extracts as shown by their lower MICs for both the Gram positive and Gram negative MDRs. MTT cytotoxicity assay showed that the highest concentration (100 μg/ml) of P. betle ethanol extract tested was not toxic to normal human dermal fibroblasts (HDFn). Data from the study firmly established P. betle as an alternative source of anti-infectives against multiple drug resistant bacteria.
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47
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Catania C, Ajo-Franklin C, Bazan GC. Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis. RSC Adv 2016. [DOI: 10.1039/c6ra23083k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Conjugated oligoelectrolytes (COE) increase outer membrane permeability inEscherichia coli,improve transport of small molecules through the cell envelope and thus accelerate whole-cell catalysis.
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Affiliation(s)
- Chelsea Catania
- Materials Department
- University of California
- Santa Barbara 93106
- USA
| | - Caroline M. Ajo-Franklin
- Physical Biosciences Division
- Materials Science Division and Synthetic Biology Institute
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Guillermo C. Bazan
- Center for Polymers and Organic Solids
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara 93106
- USA
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Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli. Appl Microbiol Biotechnol 2015; 100:2311-25. [DOI: 10.1007/s00253-015-7152-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/08/2015] [Accepted: 11/06/2015] [Indexed: 01/03/2023]
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Couce A, Rodríguez-Rojas A, Blázquez J. Bypass of genetic constraints during mutator evolution to antibiotic resistance. Proc Biol Sci 2015; 282:20142698. [PMID: 25716795 DOI: 10.1098/rspb.2014.2698] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Genetic constraints can block many mutational pathways to optimal genotypes in real fitness landscapes, yet the extent to which this can limit evolution remains to be determined. Interestingly, mutator bacteria elevate only specific types of mutations, and therefore could be very sensitive to genetic constraints. Testing this possibility is not only clinically relevant, but can also inform about the general impact of genetic constraints in adaptation. Here, we evolved 576 populations of two mutator and one wild-type Escherichia coli to doubling concentrations of the antibiotic cefotaxime. All strains carried TEM-1, a β-lactamase enzyme well known by its low availability of mutational pathways. Crucially, one of the mutators does not elevate any of the relevant first-step mutations known to improve cefatoximase activity. Despite this, both mutators displayed a similar ability to evolve more than 1000-fold resistance. Initial adaptation proceeded in parallel through general multi-drug resistance mechanisms. High-level resistance, in contrast, was achieved through divergent paths; with the a priori inferior mutator exploiting alternative mutational pathways in PBP3, the target of the antibiotic. These results have implications for mutator management in clinical infections and, more generally, illustrate that limits to natural selection in real organisms are alleviated by the existence of multiple loci contributing to fitness.
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Affiliation(s)
- Alejandro Couce
- Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain Unité Mixte de Recherche 1137 (IAME-INSERM), 75018 Paris, France
| | - Alexandro Rodríguez-Rojas
- Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain Institut für Biologie, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jesús Blázquez
- Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain Instituto de Biomedicina de Sevilla (IBIS), 41013 Sevilla, Spain
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Srinivasan B, Tonddast-Navaei S, Skolnick J. Ligand binding studies, preliminary structure-activity relationship and detailed mechanistic characterization of 1-phenyl-6,6-dimethyl-1,3,5-triazine-2,4-diamine derivatives as inhibitors of Escherichia coli dihydrofolate reductase. Eur J Med Chem 2015; 103:600-14. [PMID: 26414808 DOI: 10.1016/j.ejmech.2015.08.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/29/2015] [Accepted: 08/09/2015] [Indexed: 01/16/2023]
Abstract
Gram-negative bacteria are implicated in the causation of life-threatening hospital-acquired infections. They acquire rapid resistance to multiple drugs and available antibiotics. Hence, there is the need to discover new antibacterial agents with novel scaffolds. For the first time, this study explores the 1,3,5-triazine-2,4-diamine and 1,2,4-triazine-2,4-diamine group of compounds as potential inhibitors of Escherichia coli DHFR, a pivotal enzyme in the thymidine and purine synthesis pathway. Using differential scanning fluorimetry, DSF, fifteen compounds with various substitutions on either the 3rd or 4th positions on the benzene group of 6,6-dimethyl-1-(benzene)-1,3,5-triazine-2,4-diamine were shown to bind to the enzyme with varying affinities. Then, the dose dependence of inhibition by these compounds was determined. Preliminary quantitative structure-activity relationship analysis and docking studies implicate the alkyl linker group and the sulfonyl fluoride group in increasing the potency of inhibition. 4-[4-[3-(4,6-diamino-2,2-dimethyl-1,3,5-triazin-1-yl)phenyl]butyl]benzenesulfonyl fluoride (NSC120927), the best hit from the study and a molecule with no reported inhibition of E. coli DHFR, potently inhibits the enzyme with a Ki value of 42.50 ± 5.34 nM, followed by 4-[6-[4-(4,6-diamino-2,2-dimethyl-1,3,5-triazin-1-yl)phenyl]hexyl]benzenesulfonyl fluoride (NSC132279), with a Ki value of 100.9 ± 12.7 nM. Detailed kinetic characterization of the inhibition brought about by five small-molecule hits shows that these inhibitors bind to the dihydrofolate binding site with preferential binding to the NADPH-bound binary form of the enzyme. Furthermore, in search of novel diaminotriazine scaffolds, it is shown that lamotrigine, a 1,2,4-triazine-3,5-diamine and a sodium-ion channel blocker class of antiepileptic drug, also inhibits E. coli DHFR. This is the first comprehensive study on the binding and inhibition brought about by diaminotriazines of a gram-negative prokaryotic enzyme and provides valuable insights into the SAR as an aid to the discovery of novel antibiotics.
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Affiliation(s)
- Bharath Srinivasan
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, 950, Atlantic Drive, Atlanta, GA 30332, United States.
| | - Sam Tonddast-Navaei
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, 950, Atlantic Drive, Atlanta, GA 30332, United States.
| | - Jeffrey Skolnick
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, 950, Atlantic Drive, Atlanta, GA 30332, United States.
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