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Dombach JL, Christensen GL, Allgood SC, Quintana JLJ, Detweiler CS. Inhibition of multiple staphylococcal growth states by a small molecule that disrupts membrane fluidity and voltage. mSphere 2024; 9:e0077223. [PMID: 38445864 PMCID: PMC10964410 DOI: 10.1128/msphere.00772-23] [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] [Received: 12/12/2023] [Accepted: 01/26/2024] [Indexed: 03/07/2024] Open
Abstract
New molecular approaches to disrupting bacterial infections are needed. The bacterial cell membrane is an essential structure with diverse potential lipid and protein targets for antimicrobials. While rapid lysis of the bacterial cell membrane kills bacteria, lytic compounds are generally toxic to whole animals. In contrast, compounds that subtly damage the bacterial cell membrane could disable a microbe, facilitating pathogen clearance by the immune system with limited compound toxicity. A previously described small molecule, D66, terminates Salmonella enterica serotype Typhimurium (S. Typhimurium) infection of macrophages and reduces tissue colonization in mice. The compound dissipates bacterial inner membrane voltage without rapid cell lysis under broth conditions that permeabilize the outer membrane or disable efflux pumps. In standard media, the cell envelope protects Gram-negative bacteria from D66. We evaluated the activity of D66 in Gram-positive bacteria because their distinct envelope structure, specifically the absence of an outer membrane, could facilitate mechanism of action studies. We observed that D66 inhibited Gram-positive bacterial cell growth, rapidly increased Staphylococcus aureus membrane fluidity, and disrupted membrane voltage while barrier function remained intact. The compound also prevented planktonic staphylococcus from forming biofilms and a disturbed three-dimensional structure in 1-day-old biofilms. D66 furthermore reduced the survival of staphylococcal persister cells and of intracellular S. aureus. These data indicate that staphylococcal cells in multiple growth states germane to infection are susceptible to changes in lipid packing and membrane conductivity. Thus, agents that subtly damage bacterial cell membranes could have utility in preventing or treating disease.IMPORTANCEAn underutilized potential antibacterial target is the cell membrane, which supports or associates with approximately half of bacterial proteins and has a phospholipid makeup distinct from mammalian cell membranes. Previously, an experimental small molecule, D66, was shown to subtly damage Gram-negative bacterial cell membranes and to disrupt infection of mammalian cells. Here, we show that D66 increases the fluidity of Gram-positive bacterial cell membranes, dissipates membrane voltage, and inhibits the human pathogen Staphylococcus aureus in several infection-relevant growth states. Thus, compounds that cause membrane damage without lysing cells could be useful for mitigating infections caused by S. aureus.
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Affiliation(s)
- Jamie L. Dombach
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Grace L. Christensen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Samual C. Allgood
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Joaquin L. J. Quintana
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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2
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Chen YN, Li HL, Huang JJ, Li MJ, Liao T, Zu XY. Antimicrobial activities and mechanism of sturgeon spermary protein extracts against Escherichia coli. Front Nutr 2022; 9:1021338. [PMID: 36263303 PMCID: PMC9575452 DOI: 10.3389/fnut.2022.1021338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
This study aimed to evaluate the antimicrobial activities and mechanism of sturgeon spermary protein extracts (SSPE) against Escherichia coli. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Cell structural change was analyzed using scanning electron microscopy-energy dispersive X-ray spectrometry and transmission electron microscope. Moreover, pH, zeta potential, membrane potential, intracellular ATP concentrations and the interaction of SSPE with genomic DNA were analyzed. Results showed that molecular weight of SSPE is 13.4 kDa, the content of basic amino acids is the highest, in which arginine accounts for 73.2%. The MIC and MBC of SSPE for E. coli were 0.05 and 5 mg/mL, respectively. After SSPE treatment, cell membrane permeability changes, zeta potential decrease and genomic DNA lysis occurred in E. coli, which indicated it exerted bacteriostatic effects either independently or simultaneously by destroying the cell membrane and genomic DNA. These findings indicated that SSPE has potential to be a natural antiseptic.
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Affiliation(s)
- Ya-Nan Chen
- Institute of Agricultural Products Processing and Nuclear Agricultural Technology, Hubei Academy of Agricultural Sciences, Wuhan, China,School of Biological Engineering and Food, Hubei University of Technology, Wuhan, China
| | - Hai-Lan Li
- Institute of Agricultural Products Processing and Nuclear Agricultural Technology, Hubei Academy of Agricultural Sciences, Wuhan, China,Key Laboratory of Agricultural Products Cold Chain Logistics, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Jia-Jun Huang
- School of Biological Engineering and Food, Hubei University of Technology, Wuhan, China
| | - Mei-Jin Li
- School of Biological Engineering and Food, Hubei University of Technology, Wuhan, China
| | - Tao Liao
- Institute of Agricultural Products Processing and Nuclear Agricultural Technology, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Xiao-Yan Zu
- Institute of Agricultural Products Processing and Nuclear Agricultural Technology, Hubei Academy of Agricultural Sciences, Wuhan, China,Key Laboratory of Agricultural Products Cold Chain Logistics, Ministry of Agriculture and Rural Affairs, Wuhan, China,*Correspondence: Xiao-Yan Zu
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3
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Cai Y, Zou G, Xi M, Hou Y, Shen H, Ao J, Li M, Wang J, Luo A. Juglone Inhibits Listeria monocytogenes ATCC 19115 by Targeting Cell Membrane and Protein. Foods 2022; 11:foods11172558. [PMID: 36076744 PMCID: PMC9455723 DOI: 10.3390/foods11172558] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/12/2022] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
Foodborne disease caused by Listeria monocytogenes is a major global food safety problem. A potential solution is the antimicrobial development of the highly bioactive natural product juglone, yet few studies exist on its antibacterial mechanism against L. monocytogenes. Thus, we aimed to elucidate the antibacterial mechanism of action of juglone against L. monocytogenes by determining the resultant cell morphology, membrane permeability, membrane integrity, and proteome changes. The minimum inhibitory concentration of juglone against L. monocytogenes was 50 μg/mL, and L. monocytogenes treated with juglone had longer lag phases compared to controls. Juglone induced L. monocytogenes cell dysfunction, leakage of potassium ions, and membrane potential hyperpolarization. Confocal laser scanning microscopy and field-emission-gun scanning electron microscope assays revealed clear membrane damage due to juglone treatment. Fourier transform infrared analyses showed that L. monocytogenes responded to juglone by some conformational and compositional changes in the molecular makeup of the cell membrane. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that juglone either destroyed proteins or inhibited proteins synthesis in L. monocytogenes. Therefore, our findings established juglone as a natural antibacterial agent with potential to control foodborne L. monocytogenes infections.
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4
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Garcia BA, McDaniel MS, Loughran AJ, Johns JD, Narayanaswamy V, Fernandez Petty C, Birket SE, Baker SM, Barnaby R, Stanton BA, Foote JB, Rowe SM, Swords WE. Poly (acetyl, arginyl) glucosamine disrupts Pseudomonas aeruginosa biofilms and enhances bacterial clearance in a rat lung infection model. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35077346 PMCID: PMC8914243 DOI: 10.1099/mic.0.001121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer that has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity, which can normalize the rheological properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro, and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, and may warrant further evaluation as a therapeutic.
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Affiliation(s)
- Bryan A Garcia
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Medical University of South Carolina, Charleston, SC, USA.,Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Melissa S McDaniel
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Allister J Loughran
- Synedgen, Inc., Claremont, CA, USA.,St Jude Children's Research Hospital, Memphis, TN, USA
| | - J Dixon Johns
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | | | | | - Susan E Birket
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department of Cell Developmental and Integrative Physiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Shenda M Baker
- Synedgen, Inc., Claremont, CA, USA.,Synspira Therapeutics, Inc., Framingham, MA, USA
| | - Roxanna Barnaby
- Dartmouth Cystic Fibrosis Research Center, New Hanover, NH, USA
| | - Bruce A Stanton
- Dartmouth Cystic Fibrosis Research Center, New Hanover, NH, USA
| | - Jeremy B Foote
- Comparative Pathology Laboratory, at University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department of Cell Developmental and Integrative Physiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - W Edward Swords
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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5
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Jia R, Ge S, Ren S, Luo Y, Xiu L, Sanabil, Liu H, Cai D. Antibacterial mechanism of adzuki bean seed coat polyphenols and their potential application in preservation of fresh raw beef. Int J Food Sci Technol 2021. [DOI: 10.1111/ijfs.15292] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Rui Jia
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
| | - Sitong Ge
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
| | - Shida Ren
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
| | - Yanfei Luo
- ChangChun Customs District P.R.CHINA Changchun China
| | - Lin Xiu
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
| | - Sanabil
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
- University of Central Punjab Lahore Pakistan
| | - Huimin Liu
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
| | - Dan Cai
- College of Food Science and Engineering Jilin Agricultural University Changchun China
- National Engineering laboratory for Wheat and Corn Deep Processing Changchun China
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6
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Luo X, Ye X, Ding L, Zhu W, Yi P, Zhao Z, Gao H, Shu Z, Li S, Sang M, Wang J, Zhong W, Chen Z. Fine-Tuning of Alkaline Residues on the Hydrophilic Face Provides a Non-toxic Cationic α-Helical Antimicrobial Peptide Against Antibiotic-Resistant ESKAPE Pathogens. Front Microbiol 2021; 12:684591. [PMID: 34335511 PMCID: PMC8319832 DOI: 10.3389/fmicb.2021.684591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/11/2021] [Indexed: 11/18/2022] Open
Abstract
Antibiotic-resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) has become a serious threat to public health worldwide. Cationic α-helical antimicrobial peptides (CαAMPs) have attracted much attention as promising solutions in post-antibiotic era. However, strong hemolytic activity and in vivo inefficacy have hindered their pharmaceutical development. Here, we attempt to address these obstacles by investigating BmKn2 and BmKn2-7, two scorpion-derived CαAMPs with the same hydrophobic face and a distinct hydrophilic face. Through structural comparison, mutant design and functional analyses, we found that while keeping the hydrophobic face unchanged, increasing the number of alkaline residues (i.e., Lys + Arg residues) on the hydrophilic face of BmKn2 reduces the hemolytic activity and broadens the antimicrobial spectrum. Strikingly, when keeping the total number of alkaline residues constant, increasing the number of Lys residues on the hydrophilic face of BmKn2-7 significantly reduces the hemolytic activity but does not influence the antimicrobial activity. BmKn2-7K, a mutant of BmKn2-7 in which all of the Arg residues on the hydrophilic face were replaced with Lys, showed the lowest hemolytic activity and potent antimicrobial activity against antibiotic-resistant ESKAPE pathogens. Moreover, in vivo experiments indicate that BmKn2-7K displays potent antimicrobial efficacy against both the penicillin-resistant S. aureus and the carbapenem- and multidrug-resistant A. baumannii, and is non-toxic at the antimicrobial dosages. Taken together, our work highlights the significant functional disparity of Lys vs Arg in the scorpion-derived antimicrobial peptide BmKn2-7, and provides a promising lead molecule for drug development against ESKAPE pathogens.
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Affiliation(s)
- Xudong Luo
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China.,Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, China
| | - Xiangdong Ye
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China.,Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, China
| | - Li Ding
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China.,Department of Clinical Laboratory, Dongfeng Hospital, Hubei University of Medicine, Shiyan, China
| | - Wen Zhu
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Pengcheng Yi
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Zhiwen Zhao
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Huanhuan Gao
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Zhan Shu
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Shan Li
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Ming Sang
- Central Laboratory of Xiangyang No. 1 People's Hospital, Hubei University of Medicine, Shiyan, China
| | - Jue Wang
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Weihua Zhong
- Department of Rehabilitation Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Zongyun Chen
- Institute of Biomedicine and Hubei Key Laboratory of Embryonic Stem Cell Research, College of Basic Medicine, Hubei University of Medicine, Shiyan, China.,Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, China
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7
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Luo X, Ye X, Ding L, Zhu W, Zhao Z, Luo D, Liu N, Sun L, Chen Z. Identification of the scorpion venom-derived antimicrobial peptide Hp1404 as a new antimicrobial agent against carbapenem-resistant Acinetobacter baumannii. Microb Pathog 2021; 157:104960. [PMID: 34022355 DOI: 10.1016/j.micpath.2021.104960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 01/02/2023]
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) is becoming a troublesome issue worldwide, and anti-CRAB drug research and development is urgently needed. To identify new anti-CRAB drug leads, we investigated seven scorpion venom-derived α-helical peptides that differ in their sequence composition and length. Three peptides, Hp1404, ctriporin and Im5, showed antimicrobial activities against Acinetobacter baumannii. Further antimicrobial assays revealed that Hp1404 exhibited the best cell selectivity with high anti-CRAB and low hemolytic activities. Fluorescence assays demonstrated that Hp1404 can induce dose-dependent disruptions of the bacterial cell membrane, implying a membrane-lytic mode of action. Taken together, our work sheds light on the potential of the scorpion venom-derived peptide Hp1404 for the development of novel antimicrobial agents against CRAB infections.
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Affiliation(s)
- Xudong Luo
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China
| | - Xiangdong Ye
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China
| | - Li Ding
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Department of Clinical Laboratory, Dongfeng Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Wen Zhu
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Zhiwen Zhao
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Dan Luo
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Na Liu
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Luyue Sun
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China.
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8
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Luo X, Ding L, Ye X, Zhu W, Zhang K, Li F, Jiang H, Zhao Z, Chen Z. An Smp43-Derived Short-Chain α-Helical Peptide Displays a Unique Sequence and Possesses Antimicrobial Activity against Both Gram-Positive and Gram-Negative Bacteria. Toxins (Basel) 2021; 13:toxins13050343. [PMID: 34064808 PMCID: PMC8150835 DOI: 10.3390/toxins13050343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 01/15/2023] Open
Abstract
Scorpion venoms are rich resources of antimicrobial peptides (AMPs). While the short-chain noncysteine-containing AMPs have attracted much attention as templates for drug development, the antimicrobial potential of long-chain noncysteine-containing AMPs has been largely overlooked. Here, by using the online HeliQuest server, we designed and analyzed a series of 14-residue fragments of Smp43, a 43-residue long-chain noncysteine-containing AMP identified from the venom of Scorpio maurus palmatus. We found that Smp43(1-14) shows high antimicrobial activity against both Gram-positive and Gram-negative bacteria and is nontoxic to mammalian cells at the antimicrobial dosage. Sequence alignments showed that the designed Smp43(1-14) displays a unique primary structure that is different from other natural short-chain noncysteine-containing AMPs from scorpions, such as Uy17, Uy192 and IsCT. Moreover, the peptide Smp43(1-14) caused concentration-dependent fluorescence increases in the bacteria for all of the tested dyes, propidium iodide, SYTOXTM Green and DiSC3-5, suggesting that the peptide may kill the bacteria through the formation of pore structures in the plasma membrane. Taken together, our work sheds light on a new avenue for the design of novel short-chain noncysteine-containing AMPs and provides a good peptide template with a unique sequence for the development of novel drugs for use against bacterial infectious diseases.
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Affiliation(s)
- Xudong Luo
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan 442000, China
| | - Li Ding
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
- Department of Clinical Laboratory, Dongfeng Hospital, Hubei University of Medicine, Shiyan 442000, China
| | - Xiangdong Ye
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan 442000, China
| | - Wen Zhu
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
| | - Kaiyue Zhang
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
| | - Fangyan Li
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
| | - Huiwen Jiang
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
| | - Zhiwen Zhao
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
| | - Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China; (X.L.); (L.D.); (X.Y.); (W.Z.); (K.Z.); (F.L.); (H.J.); (Z.Z.)
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan 442000, China
- Correspondence: ; Tel.: +86-(0)-719-8469073
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9
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Zhao Z, Zhang K, Zhu W, Ye X, Ding L, Jiang H, Li F, Chen Z, Luo X. Two new cationic α-helical peptides identified from the venom gland of Liocheles australasiae possess antimicrobial activity against methicillin-resistant staphylococci. Toxicon 2021; 196:63-73. [PMID: 33836178 DOI: 10.1016/j.toxicon.2021.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/29/2021] [Accepted: 04/02/2021] [Indexed: 12/12/2022]
Abstract
Methicillin-resistant staphylococci have become growing threats to human health, and novel antimicrobials are urgently needed. Natural antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics. Here, two novel cationic α-helical antimicrobial peptides, Lausporin-1 and Lausporin-2, were identified from the venom gland of the scorpion L. australasiae through a cDNA library screening strategy. Biochemical analyses demonstrated that Lausporin-1 and Lausporin-2 are cationic α-helical amphipathic molecules. Antimicrobial assays demonstrated that the two peptides possess antibacterial activities against several species of antibiotic-resistant staphylococci. Importantly, they are active against methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus capitis, with the minimum inhibitory concentrations ranging from 2.5 to 10 μg/ml. Moreover, both peptides can induce dose-dependent plasma membrane disruptions of the bacteria. In short, our work expands the knowledge of the scorpion L. australasiae venom-derived AMPs and sheds light on the potential of Lausporin-1 and Lausporin-2 in the development of novel drugs against methicillin-resistant staphylococci.
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Affiliation(s)
- Zhiwen Zhao
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Kaiyue Zhang
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Wen Zhu
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Xiangdong Ye
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China
| | - Li Ding
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Department of Clinical Laboratory, Dongfeng Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Huiwen Jiang
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Fangyan Li
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China
| | - Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China
| | - Xudong Luo
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine, Shiyan, 442000, China.
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10
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Narayanaswamy VP, Keagy LL, Duris K, Wiesmann W, Loughran AJ, Townsend SM, Baker S. Novel Glycopolymer Eradicates Antibiotic- and CCCP-Induced Persister Cells in Pseudomonas aeruginosa. Front Microbiol 2018; 9:1724. [PMID: 30123191 PMCID: PMC6085434 DOI: 10.3389/fmicb.2018.01724] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/11/2018] [Indexed: 11/13/2022] Open
Abstract
Antibiotic treatments often fail to completely eradicate a bacterial infection, leaving behind an antibiotic-tolerant subpopulation of intact bacterial cells called persisters. Persisters are considered a major cause for treatment failure and are thought to greatly contribute to the recalcitrance of chronic infections. Pseudomonas aeruginosa infections are commonly associated with elevated levels of drug-tolerant persister cells, posing a serious threat to human health. This study represents the first time a novel large molecule polycationic glycopolymer, poly (acetyl, arginyl) glucosamine (PAAG), has been evaluated against antibiotic and carbonyl cyanide m-chlorophenylhydrazone induced P. aeruginosa persisters. PAAG eliminated eliminated persisters at concentrations that show no significant cytotoxicity on human lung epithelial cells. PAAG demonstrated rapid bactericidal activity against both forms of induced P. aeruginosa persister cells resulting in complete eradication of the in vitro persister cells within 24 h of treatment. PAAG demonstrated greater efficacy against persisters in vitro than antibiotics currently being used to treat persistent chronic infections such as tobramycin, colistin, azithromycin, aztreonam, and clarithromycin. PAAG caused rapid permeabilization of the cell membrane and caused significant membrane depolarization in persister cells. PAAG efficacy against these bacterial subpopulations suggests it may have substantial therapeutic potential for eliminating recurrent P. aeruginosa infections.
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11
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Gonelimali FD, Lin J, Miao W, Xuan J, Charles F, Chen M, Hatab SR. Antimicrobial Properties and Mechanism of Action of Some Plant Extracts Against Food Pathogens and Spoilage Microorganisms. Front Microbiol 2018; 9:1639. [PMID: 30087662 PMCID: PMC6066648 DOI: 10.3389/fmicb.2018.01639] [Citation(s) in RCA: 232] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/02/2018] [Indexed: 11/13/2022] Open
Abstract
This work aims to evaluate the antimicrobial potential of ethanolic and water extracts of roselle (Hibiscus sabdariffa), rosemary (Rosmarinus officinalis), clove (Syzygium aromaticum), and thyme (Thymus vulgaris) on some food pathogens and spoilage microorganisms. Agar well diffusion method has been used to determine the antimicrobial activities and minimum inhibitory concentrations (MIC) of different plant extracts against Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli, Salmonella enteritidis, Vibrio parahaemolyticus, and Pseudomonas aeruginosa), and one fungus (Candida albicans). The extracts exhibited both antibacterial and antifungal activities against tested microorganisms. Ethanolic roselle extract showed significant antibacterial activity (P < 0.05) against all tested bacterial strains, while no inhibitory effect on Candida albicans (CA) was observed. Only the ethanolic extracts of clove and thyme showed antifungal effects against CA with inhibition zones ranging from 25.2 ± 1.4 to 15.8 ± 1.2 mm, respectively. Bacillus cereus (BC) appears to be the most sensitive strain to the aqueous extract of clove with a MIC of 0.315%. To enhance our understanding of antimicrobial activity mechanism of plant extracts, the changes in internal pH (pHint), and membrane potential were measured in Staphylococcus aureus (SA) and Escherichia coli (EC) cells after exposure to the plant extracts. The results indicated that the plant extracts significantly affected the cell membrane of Gram-positive and Gram-negative bacteria, as demonstrated by the decline in pHint as well as cell membrane hyperpolarization. In conclusion, plant extracts are of great value as natural antimicrobials and can use safely as food preservatives.
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Affiliation(s)
- Faraja D. Gonelimali
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
- Department of Food Science and Technology, College of Agricultural Science and Fisheries Technology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Jiheng Lin
- Zhoushan Institute of Food and Drug Inspection, Zhoushan, China
| | - Wenhua Miao
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
| | - Jinghu Xuan
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
| | - Fedrick Charles
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
| | - Meiling Chen
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
| | - Shaimaa R. Hatab
- College of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan, China
- Faculty of Environmental Agricultural Science, Arish University, North Sinai, Egypt
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12
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Shi C, Song K, Zhang X, Sun Y, Sui Y, Chen Y, Jia Z, Sun H, Sun Z, Xia X. Antimicrobial Activity and Possible Mechanism of Action of Citral against Cronobacter sakazakii. PLoS One 2016; 11:e0159006. [PMID: 27415761 PMCID: PMC4945043 DOI: 10.1371/journal.pone.0159006] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/24/2016] [Indexed: 11/19/2022] Open
Abstract
Citral is a flavor component that is commonly used in food, beverage and fragrance industries. Cronobacter sakazakii is a food-borne pathogen associated with severe illness and high mortality in neonates and infants. The objective of the present study was to evaluate antimicrobial effect of citral against C. sakazakii strains. The minimum inhibitory concentration (MIC) of citral against C. sakazakii was determined via agar dilution method, then Gompertz models were used to quantitate the effect of citral on microbial growth kinetics. Changes in intracellular pH (pHin), membrane potential, intracellular ATP concentration, and membrane integrity were measured to elucidate the possible antimicrobial mechanism. Cell morphology changes were also examined using a field emission scanning electron microscope. The MICs of citral against C. sakazakii strains ranged from 0.27 to 0.54 mg/mL, and citral resulted in a longer lag phase and lower growth rate of C. sakazakii compared to the control. Citral affected the cell membrane of C. sakazakii, as evidenced by decreased intracellular ATP concentration, reduced pHin, and cell membrane hyperpolarization. Scanning electron microscopy analysis further confirmed that C. sakazakii cell membranes were damaged by citral. These findings suggest that citral exhibits antimicrobial effect against C. sakazakii strains and could be potentially used to control C. sakazakii in foods. However, how it works in food systems where many other components may interfere with its efficacy should be tested in future research before its real application.
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Affiliation(s)
- Chao Shi
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Kaikuo Song
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiaorong Zhang
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Yi Sun
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Yue Sui
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Yifei Chen
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhenyu Jia
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Huihui Sun
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Zheng Sun
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiaodong Xia
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
- Sino-US Joint Research Center for Food Safety, Yangling, Shaanxi, China
- * E-mail:
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13
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Shi C, Zhang X, Sun Y, Yang M, Song K, Zheng Z, Chen Y, Liu X, Jia Z, Dong R, Cui L, Xia X. Antimicrobial Activity of Ferulic Acid Against Cronobacter sakazakii and Possible Mechanism of Action. Foodborne Pathog Dis 2016; 13:196-204. [PMID: 26919471 DOI: 10.1089/fpd.2015.1992] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen transmitted by food that affects mainly newborns, infants, and immune-compromised adults. In this study, the antibacterial activity of ferulic acid was tested against C. sakazakii strains. Minimum inhibitory concentration of ferulic acid against C. sakazakii strains was determined using the agar dilution method. Changes in intracellular pH, membrane potential and intracellular ATP concentration were measured to elucidate the possible antibacterial mechanism. Moreover, SYTO 9 nucleic acid staining was used to assess the effect of ferulic acid on bacterial membrane integrity. Cell morphology changes were observed under a field emission scanning electron microscope. The minimum inhibitory concentrations of ferulic acid against C. sakazakii strains ranged from 2.5 to 5.0 mg/mL. Addition of ferulic acid exerted an immediate and sustained inhibition of C. sakazakii proliferation. Ferulic acid affected the membrane integrity of C. sakazakii, as evidenced by intracellular ATP concentration decrease. Moreover, reduction of intracellular pH and cell membrane hyperpolarization were detected in C. sakazakii after exposure to ferulic acid. Reduction of green fluorescence indicated the injury of cell membrane. Electronic microscopy confirmed that cell membrane of C. sakazakii was damaged by ferulic acid. Our results demonstrate that ferulic acid has moderate antimicrobial activity against C. sakazakii. It exerts its antimicrobial action partly through causing cell membrane dysfunction and changes in cellular morphology. Considering its antimicrobial properties, together with its well-known nutritional functions, ferulic acid has potential to be developed as a supplement in infant formula or other foods to control C. sakazakii.
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Affiliation(s)
- Chao Shi
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Xiaorong Zhang
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Yi Sun
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Miaochun Yang
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Kaikuo Song
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Zhiwei Zheng
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Yifei Chen
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Xin Liu
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Zhenyu Jia
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Rui Dong
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Lu Cui
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
| | - Xiaodong Xia
- College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China
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Goto T, Hirabayashi T, Morimoto H, Yamazaki K, Inoue N, Matsuyama H, Yumoto I. Contribution of intracellular negative ion capacity to Donnan effect across the membrane in alkaliphilic Bacillus spp. J Bioenerg Biomembr 2016; 48:87-96. [PMID: 26749514 DOI: 10.1007/s10863-015-9641-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/27/2015] [Indexed: 10/22/2022]
Abstract
To elucidate the energy production mechanism of alkaliphiles, the relationship between the H(+) extrusion rate by the respiratory chain and the corresponding ATP synthesis rate was determined in the facultative alkaliphile Bacillus cohnii YN-2000 and compared with those in the obligate alkaliphile Bacillus clarkii DSM 8720(T) and the neutralophile Bacillus subtilis IAM 1026. Under high aeration condition, much higher ATP synthesis rates and larger Δψ in the alkaliphilic Bacillus spp. grown at pH 10 than those in the neutralophilic B. subtilis grown at pH 7 were observed. This high ATP productivity could be attributed to the larger Δψ in alkaliphiles than in B. subtilis because the H(+) extrusion rate in alkaliphiles cannot account for the high ATP productivity. However, the large Δψ in the alkaliphiles could not be explained only by the H(+) translocation rate in the respiratory chain in alkaliphiles. There is a possibility that the Donnan effect across the membrane has the potential to contribute to the large Δψ. To estimate the contribution of the Donnan effect to the large Δψ in alkaliphilic Bacillus spp. grown at pH 10, intracellular negative ion capacity was examined. The intracellular negative ion capacities in alkaliphiles grown at pH 10 under high aeration condition corresponding to their intracellular pH (pH 8.1) were much higher than those in alkaliphiles grown under low aeration condition. A proportional relationship is revealed between the negative ion capacity and Δψ in alkaliphiles grown under different aeration conditions. This relationship strongly suggests that the intracellular negative ion capacity contributes to the formation of Δψ through the Donnan effect in alkaliphilic Bacillus spp. grown at pH 10.
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Affiliation(s)
- Toshitaka Goto
- Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 060-8589, Japan.,Bioproduction Research Insitute, National Institute of Advanced Science and Technology, 2-17-2-1, Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido, 062-8517, Japan
| | - Toshinao Hirabayashi
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Minaminosawa, Minami-ku, Sapporo, Hokkaido, 005-8601, Japan
| | - Hajime Morimoto
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Minaminosawa, Minami-ku, Sapporo, Hokkaido, 005-8601, Japan
| | - Koji Yamazaki
- Department of Marine Bioresources Chemistry, Faculty of Fisheries, Hokkaido University, 3-1-1, Minoto-cho, Hakodate, Hokkaido, 041-0821, Japan
| | - Norio Inoue
- Department of Marine Bioresources Chemistry, Faculty of Fisheries, Hokkaido University, 3-1-1, Minoto-cho, Hakodate, Hokkaido, 041-0821, Japan
| | - Hidetoshi Matsuyama
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Minaminosawa, Minami-ku, Sapporo, Hokkaido, 005-8601, Japan
| | - Isao Yumoto
- Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido, 060-8589, Japan. .,Bioproduction Research Insitute, National Institute of Advanced Science and Technology, 2-17-2-1, Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido, 062-8517, Japan.
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15
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Shi C, Sun Y, Zhang X, Zheng Z, Yang M, Ben H, Song K, Cao Y, Chen Y, Liu X, Dong R, Xia X. Antimicrobial effect of lipoic acid against Cronobacter sakazakii. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.05.041] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Oncul S, Cuce EM, Aksu B, Inhan Garip A. Effect of extremely low frequency electromagnetic fields on bacterial membrane. Int J Radiat Biol 2015; 92:42-9. [PMID: 26514970 DOI: 10.3109/09553002.2015.1101500] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE The effect of extremely low frequency electromagnetic fields (ELF-EMF) on bacteria has attracted attention due to its potential for beneficial uses. This research aimed to determine the effect of ELF-EMF on bacterial membrane namely the membrane potential, surface potential, hydrophobicity, respiratory activity and growth. MATERIALS AND METHODS Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were subjected to ELF-EMF, 50 Hz, 1 mT for 2 h. Membrane potential was determined by fluorescence spectroscopy with or without EDTA (Ethylenediaminetetraacetic acid) with DisC3(5) (3,3-dipropylthiacarbocyanine iodide), zeta potential measurements were performed by electrophoretic mobility, hydrophobicity of the membrane was measured with MATH (Microbial Adhesion to Hydrocarbons) test, respiratory activity was determined with CTC (5-Cyano-2,3-ditolyl tetrazolium chloride), colony forming unit (CFU) and DAPI (4',6-diamidino-2-phenylindole, dihydrochloride) was used for growth determinations. RESULTS ELF-EMF caused changes in physicochemical properties of both Gram-positive and Gram-negative bacteria. Hyperpolarization was seen in S. aureus and EDTA-treated E. coli. Surface potential showed a positive shift in S. aureus contrariwise to the negative shift seen in EDTA-untreated E. coli. Respiratory activity increased in both bacteria. A slight decrease in growth was observed. CONCLUSION These results show that ELF-EMF affects the crucial physicochemical processes in both Gram-positive and Gram-negative bacteria which need further research.
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Affiliation(s)
- Sule Oncul
- a Biophysics Department , School of Medicine, Faculty of Medicine, Medeniyet University , Istanbul
| | - Esra M Cuce
- b Department of Biophysics , Marmara University School of Medicine , Istanbul , Turkey
| | - Burak Aksu
- c Department of Microbiology , Marmara University School of Medicine , Istanbul , Turkey
| | - Ayse Inhan Garip
- b Department of Biophysics , Marmara University School of Medicine , Istanbul , Turkey
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17
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Kirpichnikova AA, Rudashevskaya EL, Yemelyanov VV, Shishova MF. Ca(2+)-Transport through Plasma Membrane as a Test of Auxin Sensitivity. PLANTS (BASEL, SWITZERLAND) 2014; 3:209-22. [PMID: 27135501 PMCID: PMC4844295 DOI: 10.3390/plants3020209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 03/09/2014] [Accepted: 03/13/2014] [Indexed: 11/16/2022]
Abstract
Auxin is one of the crucial regulators of plant growth and development. The discovered auxin cytosolic receptor (TIR1) is not involved in the perception of the hormone signal at the plasma membrane. Instead, another receptor, related to the ABP1, auxin binding protein1, is supposed to be responsible for the perception at the plasma membrane. One of the fast and sensitive auxin-induced reactions is an increase of Ca(2+) cytosolic concentration, which is suggested to be dependent on the activation of Ca(2+) influx through the plasma membrane. This investigation was carried out with a plasmalemma enriched vesicle fraction, obtained from etiolated maize coleoptiles. The magnitude of Ca(2+) efflux through the membrane vesicles was estimated according to the shift of potential dependent fluorescent dye diS-C₃-(5). The obtained results showed that during coleoptiles ageing (3rd, 4th and 5th days of seedling etiolated growth) the magnitude of Ca(2+) efflux from inside-out vesicles was decreased. Addition of ABP1 led to a recovery of Ca(2+) efflux to the level of the youngest and most sensitive cells. Moreover, the efflux was more sensitive, responding from 10(-8) to 10(-6) M 1-NAA, in vesicles containing ABP1, whereas native vesicles showed the highest efflux at 10(-6) M 1-NAA. We suggest that auxin increases plasma membrane permeability to Ca(2+) and that ABP1 is involved in modulation of this reaction.
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Affiliation(s)
- Anastasia A. Kirpichnikova
- Department of Plant Physiology and Biochemistry, St. Petersburg State University, Universitetskaya emb. 7/9, St. Petersburg 199034, Russia; E-Mails: (A.A.K.); (V.V.Y.)
| | - Elena L. Rudashevskaya
- Department of Plant Physiology and Biochemistry, St. Petersburg State University, Universitetskaya emb. 7/9, St. Petersburg 199034, Russia; E-Mails: (A.A.K.); (V.V.Y.)
| | - Vladislav V. Yemelyanov
- Department of Plant Physiology and Biochemistry, St. Petersburg State University, Universitetskaya emb. 7/9, St. Petersburg 199034, Russia; E-Mails: (A.A.K.); (V.V.Y.)
- Department of Genetics and Biotechnology, St. Petersburg State University, Universitetskaya emb. 7/9, St. Petersburg 199034, Russia
| | - Maria F. Shishova
- Department of Plant Physiology and Biochemistry, St. Petersburg State University, Universitetskaya emb. 7/9, St. Petersburg 199034, Russia; E-Mails: (A.A.K.); (V.V.Y.)
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18
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Clementi EA, Marks LR, Roche-Håkansson H, Håkansson AP. Monitoring changes in membrane polarity, membrane integrity, and intracellular ion concentrations in Streptococcus pneumoniae using fluorescent dyes. J Vis Exp 2014:e51008. [PMID: 24637356 DOI: 10.3791/51008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact cellular functions, including energetics and signal transductions. While both fluorescent and electrophysiological methods, including electrode usage and patch-clamping, have been well developed for measuring these events in eukaryotic cells, methodology for measuring similar events in microorganisms have proven more challenging to develop given their small size in combination with the more complex outer surface of bacteria shielding the membrane. During our studies of death-initiation in Streptococcus pneumoniae (pneumococcus), we wanted to elucidate the role of membrane events, including changes in polarity, integrity, and intracellular ion concentrations. Searching the literature, we found that very few studies exist. Other investigators had monitored radioisotope uptake or equilibrium to measure ion fluxes and membrane potential and a limited number of studies, mostly in Gram-negative organisms, had seen some success using carbocyanine or oxonol fluorescent dyes to measure membrane potential, or loading bacteria with cell-permeant acetoxymethyl (AM) ester versions of ion-sensitive fluorescent indicator dyes. We therefore established and optimized protocols for measuring membrane potential, rupture, and ion-transport in the Gram-positive organism S. pneumoniae. We developed protocols using the bis-oxonol dye DiBAC4(3) and the cell-impermeant dye propidium iodide to measure membrane depolarization and rupture, respectively, as well as methods to optimally load the pneumococci with the AM esters of the ratiometric dyes Fura-2, PBFI, and BCECF to detect changes in intracellular concentrations of Ca(2+), K(+), and H(+), respectively, using a fluorescence-detection plate reader. These protocols are the first of their kind for the pneumococcus and the majority of these dyes have not been used in any other bacterial species. Though our protocols have been optimized for S. pneumoniae, we believe these approaches should form an excellent starting-point for similar studies in other bacterial species.
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Affiliation(s)
- Emily A Clementi
- Department of Microbiology and Immunology, University at Buffalo, State University of New York
| | - Laura R Marks
- Department of Microbiology and Immunology, University at Buffalo, State University of New York
| | | | - Anders P Håkansson
- Department of Microbiology and Immunology, University at Buffalo, State University of New York; Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, State University of New York; New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, State University of New York;
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19
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Lamers RP, Cavallari JF, Burrows LL. The efflux inhibitor phenylalanine-arginine beta-naphthylamide (PAβN) permeabilizes the outer membrane of gram-negative bacteria. PLoS One 2013; 8:e60666. [PMID: 23544160 PMCID: PMC3609863 DOI: 10.1371/journal.pone.0060666] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/01/2013] [Indexed: 11/19/2022] Open
Abstract
Active efflux of antimicrobial agents is a primary mechanism by which bacterial pathogens can become multidrug resistant. The combined use of efflux pump inhibitors (EPIs) with pump substrates is under exploration to overcome efflux-mediated multidrug resistance. Phenylalanine-arginine β-naphthylamide (PAβN) is a well-studied EPI that is routinely combined with fluoroquinolone antibiotics, but few studies have assessed its utility in combination with β-lactam antibiotics. The initial goal of this study was to assess the efficacy of β-lactams in combination with PAβN against the opportunistic pathogen, Pseudomonas aeruginosa. PAβN reduced the minimal inhibitory concentrations (MICs) of several β-lactam antibiotics against P. aeruginosa; however, the susceptibility changes were not due entirely to efflux inhibition. Upon PAβN treatment, intracellular levels of the chromosomally-encoded AmpC β-lactamase that inactivates β-lactam antibiotics were significantly reduced and AmpC levels in supernatants correspondingly increased, potentially due to permeabilization of the outer membrane. PAβN treatment caused a significant increase in uptake of 8-anilino-1-naphthylenesulfonic acid, a fluorescent hydrophobic probe, and sensitized P. aeruginosa to bulky antibiotics (e.g. vancomycin) that are normally incapable of crossing the outer membrane, as well as to detergent-like bile salts. Supplementation of growth media with magnesium to stabilize the outer membrane increased MICs in the presence of PAβN and restored resistance to vancomycin. Thus, PAβN permeabilizes bacterial membranes in a concentration-dependent manner at levels below those typically used in combination studies, and this additional mode of action should be considered when using PAβN as a control for efflux studies.
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Affiliation(s)
- Ryan P. Lamers
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Joseph F. Cavallari
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Lori L. Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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20
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Ouberai M, El Garch F, Bussiere A, Riou M, Alsteens D, Lins L, Baussanne I, Dufrêne YF, Brasseur R, Decout JL, Mingeot-Leclercq MP. The Pseudomonas aeruginosa membranes: A target for a new amphiphilic aminoglycoside derivative? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1716-27. [DOI: 10.1016/j.bbamem.2011.01.014] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/05/2011] [Accepted: 01/23/2011] [Indexed: 12/31/2022]
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21
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Extracts of edible and medicinal plants damage membranes of Vibrio cholerae. Appl Environ Microbiol 2010; 76:6888-94. [PMID: 20802077 DOI: 10.1128/aem.03052-09] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The use of natural compounds from plants can provide an alternative approach against food-borne pathogens. The mechanisms of action of most plant extracts with antimicrobial activity have been poorly studied. In this work, changes in membrane integrity, membrane potential, internal pH (pH(in)), and ATP synthesis were measured in Vibrio cholerae cells after exposure to extracts of edible and medicinal plants. A preliminary screen of methanolic, ethanolic, and aqueous extracts of medicinal and edible plants was performed. Minimal bactericidal concentrations (MBCs) were measured for extracts showing high antimicrobial activity. Our results indicate that methanolic extracts of basil (Ocimum basilicum L.), nopal cactus (Opuntia ficus-indica var. Villanueva L.), sweet acacia (Acacia farnesiana L.), and white sagebrush (Artemisia ludoviciana Nutt.) are the most active against V. cholera, with MBCs ranging from 0.5 to 3.0 mg/ml. Using four fluorogenic techniques, we studied the membrane integrity of V. cholerae cells after exposure to these four extracts. Extracts from these plants were able to disrupt the cell membranes of V. cholerae cells, causing increased membrane permeability, a clear decrease in cytoplasmic pH, cell membrane hyperpolarization, and a decrease in cellular ATP concentration in all strains tested. These four plant extracts could be studied as future alternatives to control V. cholerae contamination in foods and the diseases associated with this microorganism.
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Chongsiriwatana NP, Barron AE. Comparing bacterial membrane interactions of antimicrobial peptides and their mimics. Methods Mol Biol 2010; 618:171-82. [PMID: 20094865 DOI: 10.1007/978-1-60761-594-1_12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Interactions with bacterial membranes are integral to the mechanisms of action of all antimicrobial peptides (AMPs), regardless of their final cellular targets. Here, we describe in detail two biophysical techniques that can be used to measure the membrane activities of AMPs and antimicrobial peptidomimetics: (1) a calcein leakage assay to investigate interactions between AMPs/peptidomimetics with large unilamellar vesicles and (2) a potential-sensitive dye-based depolarization assay to investigate interactions with the membranes of live bacteria. By comparing the membrane interactions of AMPs and their mimics, these techniques can provide insights into their extent of mimicry and their antimicrobial mechanisms.
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Joanne P, Falord M, Chesneau O, Lacombe C, Castano S, Desbat B, Auvynet C, Nicolas P, Msadek T, El Amri C. Comparative study of two plasticins: specificity, interfacial behavior, and bactericidal activity. Biochemistry 2009; 48:9372-83. [PMID: 19711984 DOI: 10.1021/bi901222p] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A comparative study was designed to evaluate the staphylococcidal efficiency of two sequence-related plasticins from the dermaseptin superfamily we screened previously. Their bactericidal activities against Staphylococcus aureus as well as their chemotactic potential were investigated. The impact of the GraS/GraR two-component system involved in regulating resistance to cationic antimicrobial peptides (CAMPs) was evaluated. Membrane disturbing activity was quantified by membrane depolarization assays using the diS-C3 probe and by membrane integrity assays measuring beta-galactosidase activity with recombinant strain ST1065 reflecting compromised membranes and cytoplasmic leakage. Interactions of plasticins with membrane models composed of either zwitterionic lipids mimicking the S. aureus membrane of CAMP-resistant strains or anionic lipids mimicking the negative charge-depleted membrane of CAMP-sensitive strains were analyzed by jointed Brewster angle microscopy (BAM), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and differential scanning calorimetry (DSC) to yield detailed information about the macroscopic interfacial organization, in situ conformation, orientation of the peptides at the lipid-solvent interface, and lipid-phase disturbance. We clearly found evidence of distinct interfacial behaviors of plasticins we linked to the distribution of charges along the peptides and structural interconversion properties at the membrane interface. Our results also suggest that amidation might play a key role in GraS/GraR-mediated CAMP sensing at the bacterial surface.
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Affiliation(s)
- Pierre Joanne
- Universite Pierre et Marie Curie, ER3-Biogenese des signaux peptidiques, 75251 Paris Cedex 05, France
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Bot C, Prodan C. Probing the membrane potential of living cells by dielectric spectroscopy. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 38:1049-59. [DOI: 10.1007/s00249-009-0507-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 06/02/2009] [Accepted: 06/08/2009] [Indexed: 11/29/2022]
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Smallwood CR, Marco AG, Xiao Q, Trinh V, Newton SMC, Klebba PE. Fluoresceination of FepA during colicin B killing: effects of temperature, toxin and TonB. Mol Microbiol 2009; 72:1171-80. [PMID: 19432807 PMCID: PMC3082853 DOI: 10.1111/j.1365-2958.2009.06715.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We studied the reactivity of 35 genetically engineered Cys sulphydryl groups at different locations in Escherichia coli FepA. Modification of surface loop residues by fluorescein maleimide (FM) was strongly temperature-dependent in vivo, whereas reactivity at other sites was much less affected. Control reactions with bovine serum albumin showed that the temperature dependence of loop residue reactivity was unusually high, indicating that conformational changes in multiple loops (L2, L3, L4, L5, L7, L8, L10) transform the receptor to a more accessible form at 37 degrees C. At 0 degrees C colicin B binding impaired or blocked labelling at 8 of 10 surface loop sites, presumably by steric hindrance. Overall, colicin B adsorption decreased the reactivity of more than half of the 35 sites, in both the N- and C- domains of FepA. However, colicin B penetration into the cell at 37 degrees C did not augment the chemical modification of any residues in FepA. The FM modification patterns were similarly unaffected by the tonB locus. FepA was expressed at lower levels in a tonB host strain, but when we accounted for this decrease its FM labelling was comparable whether TonB was present or absent. Thus we did not detect TonB-dependent structural changes in FepA, either alone or when it interacted with colicin B at 37 degrees C. The only changes in chemical modification were reductions from steric hindrance when the bacteriocin bound to the receptor protein. The absence of increases in the reactivity of N-domain residues argues against the idea that the colicin B polypeptide traverses the FepA channel.
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Affiliation(s)
| | | | - Qiaobin Xiao
- The Department of Chemistry & Biochemistry University of Oklahoma, Norman OK 73019
| | - Vy Trinh
- The Department of Chemistry & Biochemistry University of Oklahoma, Norman OK 73019
| | - Salete M. C. Newton
- The Department of Chemistry & Biochemistry University of Oklahoma, Norman OK 73019
| | - Phillip E. Klebba
- The Department of Chemistry & Biochemistry University of Oklahoma, Norman OK 73019
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Abstract
We develop a theoretical framework to describe the dielectric response of live cells in suspensions when placed in low external electric fields. The treatment takes into account the presence of the cell's membrane and of the charge movement at the membrane's surfaces. For spherical cells suspended in aqueous solutions, we give an analytic solution for the dielectric function, which is shown to account for the alpha- and beta-plateaus seen in many experimental data. The effect of different physical parameters on the dielectric curves is methodically analyzed.
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Brooijmans RJW, Poolman B, Schuurman-Wolters GK, de Vos WM, Hugenholtz J. Generation of a membrane potential by Lactococcus lactis through aerobic electron transport. J Bacteriol 2007; 189:5203-9. [PMID: 17496098 PMCID: PMC1951855 DOI: 10.1128/jb.00361-07] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis, a facultative anaerobic lactic acid bacterium, is known to have an increased growth yield when grown aerobically in the presence of heme. We have now established the presence of a functional, proton motive force-generating electron transfer chain (ETC) in L. lactis under these conditions. Proton motive force generation in whole cells was measured using a fluorescent probe (3',3'-dipropylthiadicarbocyanine), which is sensitive to changes in membrane potential (Delta psi). Wild-type cells, grown aerobically in the presence of heme, generated a Delta psi even in the presence of the F(1)-F(o) ATPase inhibitor N,N'-dicyclohexylcarbodiimide, while a cytochrome bd-negative mutant strain (CydA Delta) did not. We also observed high oxygen consumption rates by membrane vesicles prepared from heme-grown cells, compared to CydA Delta cells, upon the addition of NADH. This demonstrates that NADH is an electron donor for the L. lactis ETC and demonstrates the presence of a membrane-bound NADH-dehydrogenase. Furthermore, we show that the functional respiratory chain is present throughout the exponential and late phases of growth.
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Affiliation(s)
- R J W Brooijmans
- Kluyver Centre for Genomics of Industrial Fermentation, Wageningen Centre for Food Sciences, Wageningen, The Netherland
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Lo CJ, Leake MC, Pilizota T, Berry RM. Nonequivalence of membrane voltage and ion-gradient as driving forces for the bacterial flagellar motor at low load. Biophys J 2007; 93:294-302. [PMID: 17416615 PMCID: PMC1914430 DOI: 10.1529/biophysj.106.095265] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many bacterial species swim using flagella. The flagellar motor couples ion flow across the cytoplasmic membrane to rotation. Ion flow is driven by both a membrane potential (V(m)) and a transmembrane concentration gradient. To investigate their relation to bacterial flagellar motor function we developed a fluorescence technique to measure V(m) in single cells, using the dye tetramethyl rhodamine methyl ester. We used a convolution model to determine the relationship between fluorescence intensity in images of cells and intracellular dye concentration, and calculated V(m) using the ratio of intracellular/extracellular dye concentration. We found V(m) = -140 +/- 14 mV in Escherichia coli at external pH 7.0 (pH(ex)), decreasing to -85 +/- 10 mV at pH(ex) 5.0. We also estimated the sodium-motive force (SMF) by combining single-cell measurements of V(m) and intracellular sodium concentration. We were able to vary the SMF between -187 +/- 15 mV and -53 +/- 15 mV by varying pH(ex) in the range 7.0-5.0 and extracellular sodium concentration in the range 1-85 mM. Rotation rates for 0.35-microm- and 1-microm-diameter beads attached to Na(+)-driven chimeric flagellar motors varied linearly with V(m). For the larger beads, the two components of the SMF were equivalent, whereas for smaller beads at a given SMF, the speed increased with sodium gradient and external sodium concentration.
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Affiliation(s)
- Chien-Jung Lo
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, United Kingdom
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Wei N, Mi MT, Zhou Y. Influences of lovastatin on membrane ion flow and intracellular signaling in breast cancer cells. Cell Mol Biol Lett 2006; 12:1-15. [PMID: 17103090 PMCID: PMC6275703 DOI: 10.2478/s11658-006-0050-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 06/28/2006] [Indexed: 11/24/2022] Open
Abstract
Lovastatin, an inhibitor of cellular cholesterol synthesis, has an apparent anti-cancer property, but the detailed mechanisms of its anti-cancer effects remain poorly understood. We investigated the molecular mechanism of Lovastatin anti-tumor function through the study of its effect on membrane ion flow, gap junctional intercellular communication (GJIC), and the pathways of related signals in MCF-7 mammary cancer cells. After treatment for 24–72 h with 4, 8 or 16 μmol/L Lovastatin, cellular proliferation was examined via the MTT assay, and changes in membrane potential and cellular [Ca2+]i were monitored using confocal laser microscopy. In addition, the expression of plasma membrane calcium ATPase isoform 1 (PMCA1) mRNA was analyzed via RT-PCR, the GJIC function was examined using the scrape-loading dye transfer (SLDT) technique, and MAPK phosphorylation levels were tested with the kinase activity assay. The results showed that Lovastatin treatment significantly inhibited the growth of MCF-7 breast cancer cells. It also increased the negative value of the membrane potential, leading to the hyperpolarization of cells. Moreover, Lovastatin treatment continuously enhanced [Ca2+]i, although the levels of PMCA1 mRNA were unchanged. GJIC was also upregulated in MCF-7 cells, with transfer of LY Fluorescence reaching 4 to 5 rows of cells from the scraped line after treatment with 16 μmol/L Lovastatin for 72 h. Finally, downregulation of ERK1 and p38MAPK phosphorylation were found in Lovastatin-treated MCF-7 cells. It could be deduced that Lovastatin can induce changes in cellular hyperpolarization and intracellular Ca2+ distributions, and increase GJIC function. These effects may result in changes in the downstream signal cascade, inhibiting the growth of MCF-7 cells.
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Affiliation(s)
- Na Wei
- Department of Nutrition and Food Hygiene, Third Military Medical University, Chongqing, 400038 P.R. China
| | - Man Tian Mi
- Department of Nutrition and Food Hygiene, Third Military Medical University, Chongqing, 400038 P.R. China
| | - Yong Zhou
- Department of Nutrition and Food Hygiene, Third Military Medical University, Chongqing, 400038 P.R. China
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