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Alreshidi M, Dunstan H, Roberts T, Bardakci F, Badraoui R, Adnan M, Saeed M, Alreshidi F, Albulaihed Y, Snoussi M. Changes in Amino Acid Metabolism of Staphylococcus aureus following Growth to the Stationary Phase under Adjusted Growth Conditions. Microorganisms 2022; 10:microorganisms10081503. [PMID: 35893561 PMCID: PMC9331416 DOI: 10.3390/microorganisms10081503] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
The sharp increase in infections due to Staphylococcus aureus is associated with its ability to adapt to changes in its habitat. This study aimed to investigate the differences in the cytoplasmic amino acid profiles of a clinical strain of S. aureus under five combinations of stress-induced conditions representative of a wound site by varying temperature 35-37 °C, adding 0-5% NaCl and adjusting pH 6-8. The results indicated that aspartic acid, lysine, glutamic acid and histidine were the most abundant cytoplasmic amino acids in the control samples grown under optimal growth conditions. However, the magnitudes and levels of these amino acids were altered under the various wound site conditions, which led to differential cytoplasmic amino acid profiles as characterized by multivariate analyses (PLS-DA). The total cytoplasmic amino acid content was significantly reduced in the cells grown with 2.5% NaCl added at pH 7 and 37 °C relative to the control samples and other growth regimes. However, all combinations of enhanced stress conditions showed unique and characteristic changes in the concentration profiles of the cytoplasmic amino acids. These outcomes supported the hypothesis that bacterial cells of S. aureus maintain different metabolic homeostasis under various stress-induced conditions. The potent capability of S. aureus to constantly and rapidly acclimatize to variations within the environment may reflect the crucial feature supporting its virulence as an opportunistic pathogenic bacterium to invade the wound site. Understanding the control systems governing these marked changes in amino acids during the adaptation to the potential wound site conditions of this dangerous bacterium may offer new clinical controls to combat infection.
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Affiliation(s)
- Mousa Alreshidi
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
- Molecular Diagnostic and Personalized Therapeutics Unit, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia
- Correspondence: ; Tel.: +96-65-0549-8890
| | - Hugh Dunstan
- InnovAAte Pty Ltd., 45 Hunter Street, Newcastle, NSW 2300, Australia;
| | - Tim Roberts
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, University Drive, Callaghan, NSW 2308, Australia;
| | - Fevzi Bardakci
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
| | - Riadh Badraoui
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
- Section of Histology-Cytology, Medicine Faculty of Tunis, University of Tunis El Manar, La Rabta, Tunis 1017, Tunisia
| | - Mohd Adnan
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
| | - Mohd Saeed
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
| | - Fayez Alreshidi
- Department of Family and Community Medicine, College of Medicine, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia;
| | - Yazeed Albulaihed
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
| | - Mejdi Snoussi
- Department of Biology, College of Science, University of Ha’il, Hail P.O. Box 2440, Saudi Arabia; (F.B.); (R.B.); (M.A.); (M.S.); (Y.A.); (M.S.)
- Laboratory of Genetics, Biodiversity and Valorisation of Bioresources, High Institute of Biotechnology, University of Monastir, Monastir 5000, Tunisia
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Loffredo MR, Savini F, Bobone S, Casciaro B, Franzyk H, Mangoni ML, Stella L. Inoculum effect of antimicrobial peptides. Proc Natl Acad Sci U S A 2021; 118:e2014364118. [PMID: 34021080 PMCID: PMC8166072 DOI: 10.1073/pnas.2014364118] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The activity of many antibiotics depends on the initial density of cells used in bacterial growth inhibition assays. This phenomenon, termed the inoculum effect, can have important consequences for the therapeutic efficacy of the drugs, because bacterial loads vary by several orders of magnitude in clinically relevant infections. Antimicrobial peptides are a promising class of molecules in the fight against drug-resistant bacteria because they act mainly by perturbing the cell membranes rather than by inhibiting intracellular targets. Here, we report a systematic characterization of the inoculum effect for this class of antibacterial compounds. Minimum inhibitory concentration values were measured for 13 peptides (including all-D enantiomers) and peptidomimetics, covering more than seven orders of magnitude in inoculated cell density. In most cases, the inoculum effect was significant for cell densities above the standard inoculum of 5 × 105 cells/mL, while for lower densities the active concentrations remained essentially constant, with values in the micromolar range. In the case of membrane-active peptides, these data can be rationalized by considering a simple model, taking into account peptide-cell association, and hypothesizing that a threshold number of cell-bound peptide molecules is required in order to cause bacterial killing. The observed effect questions the clinical utility of activity and selectivity determinations performed at a fixed, standardized cell density. A routine evaluation of the dependence of the activity of antimicrobial peptides and peptidomimetics on the inoculum should be considered.
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Affiliation(s)
- Maria Rosa Loffredo
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Filippo Savini
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Sara Bobone
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Bruno Casciaro
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Maria Luisa Mangoni
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy;
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy;
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Wieland T, Assmann J, Bethe A, Fidelak C, Gmoser H, Janßen T, Kotthaus K, Lübke-Becker A, Wieler LH, Urban GA. A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation. SENSORS 2021; 21:s21082771. [PMID: 33919962 PMCID: PMC8070953 DOI: 10.3390/s21082771] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 01/15/2023]
Abstract
The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.
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Affiliation(s)
- Tobias Wieland
- Department of Microsystems Engineering (IMTEK)—Laboratory of Sensors, University of Freiburg, 79110 Freiburg, Germany; (H.G.); (K.K.); (G.A.U.)
- Correspondence: ; Tel.: +49-761-203-7268
| | - Julia Assmann
- Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany; (J.A.); (A.B.); (A.L.-B.); (L.H.W.)
- Robert Koch Institute, ZBS4 Advanced Light and Electron Microscopy, 13353 Berlin, Germany
| | - Astrid Bethe
- Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany; (J.A.); (A.B.); (A.L.-B.); (L.H.W.)
| | | | - Helena Gmoser
- Department of Microsystems Engineering (IMTEK)—Laboratory of Sensors, University of Freiburg, 79110 Freiburg, Germany; (H.G.); (K.K.); (G.A.U.)
| | | | - Krishan Kotthaus
- Department of Microsystems Engineering (IMTEK)—Laboratory of Sensors, University of Freiburg, 79110 Freiburg, Germany; (H.G.); (K.K.); (G.A.U.)
| | - Antina Lübke-Becker
- Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany; (J.A.); (A.B.); (A.L.-B.); (L.H.W.)
| | - Lothar H. Wieler
- Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany; (J.A.); (A.B.); (A.L.-B.); (L.H.W.)
- Robert Koch Institute, 13353 Berlin, Germany
| | - Gerald A. Urban
- Department of Microsystems Engineering (IMTEK)—Laboratory of Sensors, University of Freiburg, 79110 Freiburg, Germany; (H.G.); (K.K.); (G.A.U.)
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A Novel Way for Whey: Cheese Whey Fermentation Produces an Effective and Environmentally-Safe Alternative to Chlorine. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9142800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cheese whey has been described as an environmental hazard due to its high organic content. Although it has been suggested that whey can be used as food disinfectant, it continues to pose an environmental problem because it still contains a high organic load. Here, we aimed to develop a low-cost, scalable fermentation protocol to produce a disinfectant from dairy waste that has very little organic content and high levels of lactic acid. Fermentation was achieved with industrial whey from ewe, goat, and cow’s milk, using a specific mesophilic-lactic acid bacteria starter mix over 120 h, which yielded the highest lactic acid production and the lowest lactose content. Antibacterial activity was observed against Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7, plus a total of thirteen other food pathogenic and spoilage strains, and antibacterial activities were determined to be highest after 120 h. We further validated this whey’s application as a disinfectant in shredded lettuce and compared its efficacy to that of chlorine, evaluating microbial quality, texture, color, and sensory perception, pH, and O2 and CO2 determinations. Results showed that not only was microbial quality better when using our whey solution (p < 0.05), but also the quality indicators for whey were statistically similar to those treated with chlorine. Hence, our work validates the use of an industrial waste whey as a low-cost, efficient, and environmentally safe disinfectant, with potential applications for minimally processed foodstuffs as an alternative to chlorine.
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Groo AC, Matougui N, Umerska A, Saulnier P. Reverse micelle-lipid nanocapsules: a novel strategy for drug delivery of the plectasin derivate AP138 antimicrobial peptide. Int J Nanomedicine 2018; 13:7565-7574. [PMID: 30532539 PMCID: PMC6241861 DOI: 10.2147/ijn.s180040] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Introduction Resistance to traditional antibiotics is an increasingly serious problem. Antimicrobial peptides (AMPs) have emerged as a new therapeutic class with great potential against infectious diseases, as they are less prone to induce resistance. Nanotechnology-based delivery strategies can improve the efficiency and stability of AMPs, particularly against proteolytic degradation. Lipid nanocapsules (LNCs) are a new generation of biomimetic nanocarriers and were used in this study to deliver peptides. Methods AMP-loaded reverse micelles (RM) were developed and incorpo rated into LNCs by the phase inversion process and the antimicrobial activity of the AMPs-loaded LNC was evaluated by the minimum inhibitory concentration method. We studied the activity of AMP solutions and AMP-loaded LNCs against Gram-positive and Gram-negative bacterial strains and then evaluated the encapsulation of a new cationic AMP called AP138. Finally, we analyzed the effect of enzymatic attack on AP138 and AP138-RM-LNCs after incubation with trypsin. Results AP138 was efficiently encapsulated in the LNCs (encapsulation efficiency = 97.8% at a drug loading of 0.151%), resulting in protection against degradation by proteases and the preservation of antimicrobial activity against Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus. Conclusion This study shows that RM-LNCs are an excellent candidate system to deliver AMPs.
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Affiliation(s)
- Anne-Claire Groo
- Normandie Univ, UNICAEN, CERMN - EA 4258, FR CNRS 3038 INC3M, SF 4206 ICORE, Caen, France,
| | - Nada Matougui
- Micro & Nanomédecines Translationelles-MINT, UNIV Angers, INSERM U1066, CNRS UMR 6021, UBL Universite Bretagne Loire, Angers, France
| | - Anita Umerska
- Micro & Nanomédecines Translationelles-MINT, UNIV Angers, INSERM U1066, CNRS UMR 6021, UBL Universite Bretagne Loire, Angers, France.,Université de Lorraine, CITHEFOR, Nancy, France
| | - Patrick Saulnier
- Micro & Nanomédecines Translationelles-MINT, UNIV Angers, INSERM U1066, CNRS UMR 6021, UBL Universite Bretagne Loire, Angers, France.,Angers University Hospital, Angers, France
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Umerska A, Cassisa V, Bastiat G, Matougui N, Nehme H, Manero F, Eveillard M, Saulnier P. Synergistic interactions between antimicrobial peptides derived from plectasin and lipid nanocapsules containing monolaurin as a cosurfactant against Staphylococcus aureus. Int J Nanomedicine 2017; 12:5687-5699. [PMID: 28848347 PMCID: PMC5557623 DOI: 10.2147/ijn.s139625] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Development of effective antibacterial agents for the treatment of infections caused by Gram-positive bacteria resistant to existing antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA), is an area of intensive research. In this work, the antibacterial efficacy of two antimicrobial peptides derived from plectasin, AP114 and AP138, used alone and in combination with monolaurin-lipid nanocapsules (ML-LNCs) was evaluated. Several interesting findings emerged from the present study. First, ML-LNCs and both plectasin derivatives showed potent activity against all 14 tested strains of S. aureus, independent of their resistance phenotype. Both peptides displayed a considerable adsorption (33%-62%) onto ML-LNCs without having an important impact on the particle properties such as size. The combinations of peptide with ML-LNC displayed synergistic effect against S. aureus, as confirmed by two methods: checkerboard and time-kill assays. This synergistic interaction enables a dose reduction and consequently decreases the risk of toxicity and has the potential of minimizing the development of resistance. Together, these results suggest that ML-LNCs loaded with a plectasin derivative may be a very promising drug delivery system for further development as a novel antibacterial agent against S. aureus, including MRSA.
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Affiliation(s)
- Anita Umerska
- MINT, UNIV Angers, INSERM 1066, CNRS 6021, Université Bretagne Loire, Angers, Cedex, France
| | | | - Guillaume Bastiat
- MINT, UNIV Angers, INSERM 1066, CNRS 6021, Université Bretagne Loire, Angers, Cedex, France
| | - Nada Matougui
- MINT, UNIV Angers, INSERM 1066, CNRS 6021, Université Bretagne Loire, Angers, Cedex, France
| | - Hassan Nehme
- MINT, UNIV Angers, INSERM 1066, CNRS 6021, Université Bretagne Loire, Angers, Cedex, France
| | - Florence Manero
- SCIAM (Service Commun d'Imagerie et d'Analyses Microscopiques), Angers, France
| | - Matthieu Eveillard
- Equipe ATIP AVENIR, CRCINA, Inserm, Université de Nantes, Université d'Angers, Angers, France
| | - Patrick Saulnier
- MINT, UNIV Angers, INSERM 1066, CNRS 6021, Université Bretagne Loire, Angers, Cedex, France
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Lim MP, Firdaus-Raih M, Nathan S. Nematode Peptides with Host-Directed Anti-inflammatory Activity Rescue Caenorhabditis elegans from a Burkholderia pseudomallei Infection. Front Microbiol 2016; 7:1436. [PMID: 27672387 PMCID: PMC5019075 DOI: 10.3389/fmicb.2016.01436] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/30/2016] [Indexed: 01/10/2023] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is among a growing number of bacterial pathogens that are increasingly antibiotic resistant. Antimicrobial peptides (AMPs) have been investigated as an alternative approach to treat microbial infections, as generally, there is a lower likelihood that a pathogen will develop resistance to AMPs. In this study, 36 candidate Caenorhabditis elegans genes that encode secreted peptides of <150 amino acids and previously shown to be overexpressed during infection by B. pseudomallei were identified from the expression profile of infected nematodes. RNA interference (RNAi)-based knockdown of 12/34 peptide-encoding genes resulted in enhanced nematode susceptibility to B. pseudomallei without affecting worm fitness. A microdilution test demonstrated that two peptides, NLP-31 and Y43C5A.3, exhibited anti-B. pseudomallei activity in a dose dependent manner on different pathogens. Time kill analysis proposed that these peptides were bacteriostatic against B. pseudomallei at concentrations up to 8× MIC90. The SYTOX green assay demonstrated that NLP-31 and Y43C5A.3 did not disrupt the B. pseudomallei membrane. Instead, gel retardation assays revealed that both peptides were able to bind to DNA and interfere with bacterial viability. In parallel, microscopic examination showed induction of cellular filamentation, a hallmark of DNA synthesis inhibition, of NLP-31 and Y43C5A.3 treated cells. In addition, the peptides also regulated the expression of inflammatory cytokines in B. pseudomallei infected macrophage cells. Collectively, these findings demonstrate the potential of NLP-31 and Y43C5A.3 as anti-B. pseudomallei peptides based on their function as immune modulators.
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Affiliation(s)
- Mei-Perng Lim
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Mohd Firdaus-Raih
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan MalaysiaBangi, Malaysia; Malaysia Genome InstituteKajang, Malaysia
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Ng TB, Cheung RCF, Wong JH, Chan YS, Dan X, Pan W, Wang H, Guan S, Chan K, Ye X, Liu F, Xia L, Chan WY. Fungal proteinaceous compounds with multiple biological activities. Appl Microbiol Biotechnol 2016; 100:6601-6617. [PMID: 27338574 DOI: 10.1007/s00253-016-7671-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 11/30/2022]
Abstract
Fungi comprise organisms like molds, yeasts and mushrooms. They have been used as food or medicine for a long time. A large number of fungal proteins or peptides with diverse biological activities are considered as antibacterial, antifungal, antiviral and anticancer agents. They encompass proteases, ribosome inactivating proteins, defensins, hemolysins, lectins, laccases, ribonucleases, immunomodulatory proteins, and polysaccharopeptides. The target of the present review is to update the status of the various bioactivities of these fungal proteins and peptides and discuss their therapeutic potential.
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Affiliation(s)
- Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Randy Chi Fai Cheung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Jack Ho Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Yau Sang Chan
- State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, School of Medicine, Shenzhen University, Nanhai Ave 3688, 518060, Shenzhen, Guangdong, People's Republic of China
| | - Xiuli Dan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenliang Pan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Hexiang Wang
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, 100193, China
| | - Suzhen Guan
- Department of Social Medicine, College of Public Health, Xinjiang Medical University, Urumqi, 830011, China
| | - Ki Chan
- Biomedical and Tissue Engineering Research Group, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, China
| | - Xiuyun Ye
- College of Biological Sciences and Technology, Fuzhou University, Fuzhou, Fujian, China.,Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou, Fujian, China
| | - Fang Liu
- Department of Microbiology, Nankai University, Tianjin, China
| | - Lixin Xia
- State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, School of Medicine, Shenzhen University, Nanhai Ave 3688, 518060, Shenzhen, Guangdong, People's Republic of China
| | - Wai Yee Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
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10
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Water JJ, Smart S, Franzyk H, Foged C, Nielsen HM. Nanoparticle-mediated delivery of the antimicrobial peptide plectasin against Staphylococcus aureus in infected epithelial cells. Eur J Pharm Biopharm 2015; 92:65-73. [DOI: 10.1016/j.ejpb.2015.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 01/05/2015] [Accepted: 02/09/2015] [Indexed: 12/18/2022]
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Hyaluronic Acid-Based Nanogels Produced by Microfluidics-Facilitated Self-Assembly Improves the Safety Profile of the Cationic Host Defense Peptide Novicidin. Pharm Res 2015; 32:2727-35. [PMID: 25813840 DOI: 10.1007/s11095-015-1658-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/16/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Cationic host defence peptides constitute a promising class of therapeutic drug leads with a wide range of therapeutic applications, including anticancer therapy, immunomodulation, and antimicrobial activity. Although potent and efficacious, systemic toxicity and low chemical stability have hampered their commercial development. To overcome these challenges a novel nanogel-based drug delivery system was designed. METHOD The peptide novicidin was self-assembled with an octenyl succinic anhydride-modified analogue of hyaluronic acid, and this formulation was optimized using a microfluidics-based quality-by-design approach. RESULTS By applying design-of-experiment it was demonstrated that the encapsulation efficiency of novicidin (15% to 71%) and the zeta potential (-24 to -57 mV) of the nanogels could be tailored by changing the preparation process parameters, with a maximum peptide loading of 36 ± 4%. The nanogels exhibited good colloidal stability under different ionic strength conditions and allowed complete release of the peptide over 14 days. Furthermore, self-assembly of novicidin with hyaluronic acid into nanogels significantly improved the safety profile at least five-fold and six-fold when tested in HUVECs and NIH 3T3 cells, respectively, whilst showing no loss of antimicrobial activity against Escherichia coli and Staphylococcus aureus. CONCLUSION Formulation in nanogels could be a viable approach to improve the safety profile of host defence peptides.
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Levón J, Al-Samadi A, Mackiewicz Z, Coer A, Trebse R, Waris E, Konttinen YT. Human beta-defensin-3 producing cells in septic implant loosening. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:98. [PMID: 25655501 DOI: 10.1007/s10856-015-5440-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/17/2014] [Indexed: 06/04/2023]
Abstract
Human β-defensin-3 (hBD-3) has been found in synovial fluid and later in periprosthetic tissues in septic joint implant loosening. The aim of the present study was to identify its cellular sources. Tissue samples from 12 patients were analyzed. A fully automatic Leica BOND MAX staining robot was used. Affinity-purified rabbit anti-human hBD-3 IgG was applied in a two-layer horse radish peroxidase/anti-rabbit-labeled polymer method. Double immunofluorescence of hBD3 together with CD68, CD31, heat shock protein 47 (HSP47) and mast cell tryptase (MCT) staining was done. Human BD-3 was found in monocyte/macrophage-like cells, vascular endothelial cells and fibroblasts-like cells, but was weakly expressed in foreign body giant cells and negative in neutrophils. Human BD-3 was found in CD68 and CD31 immunoreactive cells, whereas HSP47 and MCT positive cells were hBD-3 negative. Immunostaining of hBD-3 was strong in some tissue areas but weak or absent in others. Monocyte/macrophages and endothelial cells were established in this study as the major cellular sources of hBD-3 in septic loosening, but fibroblasts and foreign body giant cells can also contribute to its production. The heterogeneous topological staining of hBD-3 suggests local regulation, possibly by bacterial products, damage-associated molecular patterns and cytokines. The results explain the increased synovial fluid/tissue concentrations of hBD-3 in septic loosening.
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Affiliation(s)
- Jaakko Levón
- Department of Anatomy, Institute of Biomedicine, BMH 1, PO Box 63, 00014, Helsinki, Finland,
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Chen X, Shi J, Chen R, Wen Y, Shi Y, Zhu Z, Guo S, Li L. Molecular chaperones (TrxA, SUMO, Intein, and GST) mediating expression, purification, and antimicrobial activity assays of plectasin inEscherichia coli. Biotechnol Appl Biochem 2015; 62:606-14. [PMID: 25311837 DOI: 10.1002/bab.1303] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/04/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Xin Chen
- Department of Respiratory Medicine; Zhujiang Hospital; Southern Medical University; Guangzhou People's Republic of China
| | - Jiawei Shi
- Nanfang Hospital; First Clinical Medical College; Southern Medical University; Guangzhou People's Republic of China
| | - Rui Chen
- Department of Respiratory Diseases; Sun Yat-sen Memorial Hospital; Sun Yat-sen University; Guangzhou People's Republic of China
| | - Yaoan Wen
- Nanfang Hospital; First Clinical Medical College; Southern Medical University; Guangzhou People's Republic of China
| | - Yu Shi
- Biosafety Level-3 Laboratory; School of Public Health and Tropical Medicine; Southern Medical University; Guangzhou People's Republic of China
| | - Zhe Zhu
- Department of Respiratory Medicine; Zhujiang Hospital; Southern Medical University; Guangzhou People's Republic of China
| | - Songwen Guo
- Department of Respiratory Medicine; Zhujiang Hospital; Southern Medical University; Guangzhou People's Republic of China
| | - Ling Li
- Biosafety Level-3 Laboratory; School of Public Health and Tropical Medicine; Southern Medical University; Guangzhou People's Republic of China
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14
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Leong WM, Geier R, Engstrom S, Ingham S, Ingham B, Smukowski M. Growth of Listeria monocytogenes, Salmonella spp., Escherichia coli O157:H7, and Staphylococcus aureus on cheese during extended storage at 25°C. J Food Prot 2014; 77:1275-88. [PMID: 25198588 DOI: 10.4315/0362-028x.jfp-14-047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Potentially hazardous foods require time/temperature control for safety. According to the U.S. Food and Drug Administration Food Code, most cheeses are potentially hazardous foods based on pH and water activity, and a product assessment is required to evaluate safety of storage >6 h at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15 days at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (mozzarella and Mexican-style), and reduced-sodium or reduced-fat types were tested. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (∼10(5) CFU/g). Cocktails were 10 strains of L. monocytogenes, 6 of Salmonella spp., or 5 of E. coli O157:H7 or S. aureus. Inoculated slices were vacuum packaged and stored at 25°C for ≤ 15 days, with surviving inocula enumerated every 3 days. Percent salt-in-the-moisture phase, percent titratable acidity, pH, water activity, and levels of indigenous/starter bacteria were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, 6 of SALM, 4 of LM, and 3 of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (average 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 3.02 log CFU/g (average 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (average 1.60 log CFU/g), and 0.41 to 2.90 log CFU/g (average 1.69 log CFU/g), respectively. Pathogen growth varied within cheese types or lots. Pathogen growth was influenced by pH and percent salt-in-the-moisture phase, and these two factors were used to establish growth/no-growth boundary conditions for safe, extended storage (≤25°C) of pasteurized milk cheeses. Pathogen growth/no-growth could not be predicted for Swiss-style cheeses, mold-ripened or bacterial surface-ripened cheeses, and cheeses made with nonbovine milk, as insufficient data were gathered. This challenge study data can support science-based decision making in a regulatory framework.
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Affiliation(s)
- Wan Mei Leong
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin 53706, USA
| | - Renae Geier
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin 53706, USA
| | - Sarah Engstrom
- rtech laboratories, Land O'Lakes, P.O. Box 64101, St. Paul, Minnesota 55164, USA
| | - Steve Ingham
- Division of Food Safety, Wisconsin Department of Agriculture, Trade and Consumer Protection, P.O. Box 8911, Madison, Wisconsin 53708, USA
| | - Barbara Ingham
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin 53706, USA.
| | - Marianne Smukowski
- Center for Dairy Research, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin 53706, USA
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15
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Su LC, Xie Z, Zhang Y, Nguyen KT, Yang J. Study on the Antimicrobial Properties of Citrate-Based Biodegradable Polymers. Front Bioeng Biotechnol 2014; 2:23. [PMID: 25023605 PMCID: PMC4090902 DOI: 10.3389/fbioe.2014.00023] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/17/2014] [Indexed: 02/05/2023] Open
Abstract
Citrate-based polymers possess unique advantages for various biomedical applications since citric acid is a natural metabolism product, which is biocompatible and antimicrobial. In polymer synthesis, citric acid also provides multiple functional groups to control the crosslinking of polymers and active binding sites for further conjugation of biomolecules. Our group recently developed a number of citrate-based polymers for various biomedical applications by taking advantage of their controllable chemical, mechanical, and biological characteristics. In this study, various citric acid derived biodegradable polymers were synthesized and investigated for their physicochemical and antimicrobial properties. Results indicate that citric acid derived polymers reduced bacterial proliferation to different degrees based on their chemical composition. Among the studied polymers, poly(octamethylene citrate) showed ~70-80% suppression to microbe proliferation, owing to its relatively higher ratio of citric acid contents. Crosslinked urethane-doped polyester elastomers and biodegradable photoluminescent polymers also exhibited significant bacteria reduction of ~20 and ~50% for Staphylococcus aureus and Escherichia coli, respectively. Thus, the intrinsic antibacterial properties in citrate-based polymers enable them to inhibit bacteria growth without incorporation of antibiotics, silver nanoparticles, and other traditional bacteria-killing agents suggesting that the citrate-based polymers are unique beneficial materials for wound dressing, tissue engineering, and other potential medical applications where antimicrobial property is desired.
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Affiliation(s)
- Lee-Chun Su
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Zhiwei Xie
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Yi Zhang
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Kytai Truong Nguyen
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Jian Yang
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park, PA, USA
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16
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Rajendran A, Endo M, Sugiyama H. State-of-the-Art High-Speed Atomic Force Microscopy for Investigation of Single-Molecular Dynamics of Proteins. Chem Rev 2013; 114:1493-520. [DOI: 10.1021/cr300253x] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Arivazhagan Rajendran
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho
Sakyo-ku, Kyoto 606-8502, Japan
| | - Masayuki Endo
- Institute
for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho,
Sakyo-ku, Kyoto 606-8501, Japan
- CREST, Japan Science and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Hiroshi Sugiyama
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho
Sakyo-ku, Kyoto 606-8502, Japan
- Institute
for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho,
Sakyo-ku, Kyoto 606-8501, Japan
- CREST, Japan Science and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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17
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Hein-Kristensen L, Knapp KM, Franzyk H, Gram L. Selectivity in the potentiation of antibacterial activity of α-peptide/β-peptoid peptidomimetics and antimicrobial peptides by human blood plasma. Res Microbiol 2013; 164:933-40. [DOI: 10.1016/j.resmic.2013.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 08/07/2013] [Indexed: 10/26/2022]
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18
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Alajlouni RA, Seleem MN. Targeting listeria monocytogenes rpoA and rpoD genes using peptide nucleic acids. Nucleic Acid Ther 2013; 23:363-7. [PMID: 23859300 DOI: 10.1089/nat.2013.0426] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Treating intracellular pathogens remains a considerable medical challenge because of the inefficient intracellular delivery of antimicrobials and the frequent emergence of bacterial resistance to therapeutic agents deemed the drugs of last resort. We investigated the capability of antisense peptide nucleic acids (PNAs) conjugated to the (KFF)3K cell penetrating peptide to target RNA polymerase α subunit (rpoA) and RNA polymerase sigma 70 (rpoD) in the intracellular pathogen Listeria monocytogenes. The PNAs tested displayed a concentration dependent inhibition of L. monocytogenes growth in pure culture at the micromolar level and significantly reduced intracellular L. monocytogenes in infected cell culture and Caenorhabditis elegans whole animal model. In vitro, the combined PNAs treatment was synergistic resulting in a clearance of L. monocytogenes at 0.5× the individual PNA concentration. This study demonstrates the potential of anti-rpoA PNA as an antibacterial agent and will provide the basis for improving and developing these PNAs to better target intracellular pathogens like Listeria. This study also establishes C. elegans as a potential model for the screening of PNAs.
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Affiliation(s)
- Ruba A Alajlouni
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine West Lafayette, Indiana, USA
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Zhang Y, Teng D, Mao R, Wang X, Xi D, Hu X, Wang J. High expression of a plectasin-derived peptide NZ2114 in Pichia pastoris and its pharmacodynamics, postantibiotic and synergy against Staphylococcus aureus. Appl Microbiol Biotechnol 2013; 98:681-94. [PMID: 23624708 DOI: 10.1007/s00253-013-4881-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/04/2013] [Accepted: 03/24/2013] [Indexed: 01/12/2023]
Abstract
NZ2114, a new variant of plectasin, was overexpressed in Pichia pastoris X-33 via pPICZαA for the first time. The total secreted protein of fermentation supernatant reached 2,390 mg/l (29 °C) and 2,310 mg/l (25 °C), and the recombinant NZ2114 (rNZ2114) reached 860 mg/l (29 °C) and 1,309 mg/l (25 °C) at 96 h induction in a 5-l fermentor, respectively.The rNZ2114 was purified by cation exchange chromatography, and its yield was 583 mg/l with 94.8 % purity. The minimal inhibitory concentration (MIC) of rNZ2114 to four ATCC strains of Staphyloccocus aureus was evaluated from 0.028 to 0.90 μM. Meanwhile, it showed potent activity (0.11-0.90 μM) to 20 clinical isolates of MRSA. The rNZ2114 killed over 99.9 % of tested S. aureus (ATCC 25923 and ATCC 43300) in Mueller-Hinton medium within 6 h when treated with 4 × MIC. The postantibiotic effect of rNZ2114 to S. aureus ATCC 25923 and ATCC 43300 was 18.6-45.6 and 1.7-3.5 h under 1×, 2×, and 4× MIC, respectively. The fractional inhibitory concentration index (FICI) indicated a synergistic effect between rNZ2114 and kanamycin, streptomycin, and vancomycin against S. aureus ATCC 25923 (FICI = 0.125), and additivity between rNZ2114 and ampicillin, spectinomycin (FICI = 0.625), respectively. To S. aureus ATCC 43300 [methicillin-resistant S. aureus (MRSA)], rNZ2114 showed a synergistic effect (FICI = 0.125-0.3125) with kanamycin, ampicillin, streptomycin, and vancomycin, and antagonism with spectinomycin (FICI = 8.0625). The rNZ2114 caused only less than 0.1 % hemolytic activity in the concentration of 128 μg/ml, and showed a good thermostability from 20 to 80 °C. In addition, it exhibited the highest activity at pH 8.0. These results suggested that large-scale production of NZ2114 is feasible using the P. pastoris expression system, and it could be a new potential antimicrobial agent for the prevention and treatment of S. aureus especially for MRSA infections.
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Affiliation(s)
- Yong Zhang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Beijing, 100081, China
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20
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Balakrishnan VS, Vad BS, Otzen DE. Novicidin's membrane permeabilizing activity is driven by membrane partitioning but not by helicity: a biophysical study of the impact of lipid charge and cholesterol. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:996-1002. [PMID: 23562965 DOI: 10.1016/j.bbapap.2013.03.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/05/2013] [Accepted: 03/25/2013] [Indexed: 12/11/2022]
Abstract
We have investigated the interactions between the antimicrobial peptide Novicidin (Nc) and vesicles containing the phospholipid DOPC, with various amounts of DOPG and cholesterol using circular dichroism spectroscopy, calcein release, equilibrium dialysis and isothermal titration calorimetry. Nc adopts a random coil structure in the absence of lipids and in the presence of vesicles containing 100% DOPC. Lipids with 25-40% DOPG induce the highest level of helicity in Nc; higher DOPG levels lead to lower helicity levels and an altered tertiary arrangement of the peptide. However, the ability of Nc to permeabilize vesicles correlates not with helicity but rather with its overall membrane affinity, which is enthalpically favorable but opposed by entropy. Permeabilization declines with increasing mole percentage PG. Changes in helicity correlate with changes in enthalpy, reflecting the enthalpy of helix formation, but not with affinity. There is also a large favorable enthalpic interaction between Nc and lipids in the absence of negative charge and structural changes. Cholesterol slightly reduces membrane permeabilization but has little effect on Nc affinity and secondary structure, and probably protects the membrane by inducing the liquid ordered state. We conclude that helicity is not a prerequisite for activity, and charge-charge interactions are not the only major driving force for AMP interactions with membranes. Our data are compatible with a model in which a superficial binding mode with a large membrane surface binding area per peptide is more efficient than a more intimate embedding within the membrane environment.
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Affiliation(s)
- Vijay S Balakrishnan
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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21
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Xi D, Teng D, Wang X, Mao R, Yang Y, Xiang W, Wang J. Design, expression and characterization of the hybrid antimicrobial peptide LHP7, connected by a flexible linker, against Staphylococcus and Streptococcus. Process Biochem 2013. [DOI: 10.1016/j.procbio.2013.01.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Mao R, Teng D, Wang X, Xi D, Zhang Y, Hu X, Yang Y, Wang J. Design, expression, and characterization of a novel targeted plectasin against methicillin-resistant Staphylococcus aureus. Appl Microbiol Biotechnol 2012; 97:3991-4002. [PMID: 23095942 DOI: 10.1007/s00253-012-4508-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 10/27/2022]
Abstract
A novel specifically targeted antimicrobial peptide (STAMP) that was especially effective against methicillin-resistant Staphylococcus aureus (MRSA) was designed by fusing the AgrD1 pheromone to the N-terminal end of plectasin. This STAMP was named Agplectasin, and its gene was synthesized and expressed in Pichia pastoris X-33 via pPICZαA. The highest amount of total secreted protein reached 1,285.5 mg/l at 108 h during the 120-h induction. The recombinant Agplectasin (rAgP) was purified by cation exchange chromatography and hydrophobic exchange chromatography; its yield reached 150 mg/l with 94 % purity. The rAgP exhibited strong bactericidal activity against S. aureus but not Staphylococcus epidermidis or other types of tested bacteria. A bactericidal kinetics assay showed that the rAgP killed over 99.9 % of tested S. aureus (ATCC 25923 and ATCC 43300) in both Mueller-Hinton medium and human blood within 10 h when treated with 4× minimal inhibitory concentration. The rAgP caused only approximately 1 % hemolysis of human blood cells, even when the concentration reached 512 μg/ml, making it potentially feasible as a clinical injection agent. In addition, it maintained a high activity over a wide range of pH values (2.0-10.0) and demonstrated a high thermal stability at 100 °C for 1 h. These results suggested that this STAMP has the potential to eliminate MRSA strains without disrupting the normal flora.
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Affiliation(s)
- Ruoyu Mao
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Beijing 100081, China
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23
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Blueman D, Bousfield C. The use of larval therapy to reduce the bacterial load in chronic wounds. J Wound Care 2012; 21:244-53. [DOI: 10.12968/jowc.2012.21.5.244] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - C. Bousfield
- School of Nursing, Midwifery and Physiotherapy, Division of Nursing, University of Nottingham, Queens Medical Centre, UK
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24
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Structural and Functional Analysis of Proteins by High-Speed Atomic Force Microscopy. STRUCTURAL AND MECHANISTIC ENZYMOLOGY - BRINGING TOGETHER EXPERIMENTS AND COMPUTING 2012; 87:5-55. [DOI: 10.1016/b978-0-12-398312-1.00002-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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25
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Rieg S, Kaasch AJ, Wehrle J, Hofmann SC, Szymaniak-Vits M, Saborowski V, Jonas D, Kalbacher H, Seifert H, Kern WV. Susceptibility of clinical Staphylococcus aureus isolates to innate defense antimicrobial peptides. Microbes Infect 2011; 13:761-5. [DOI: 10.1016/j.micinf.2011.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/22/2011] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
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26
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Sublethal triclosan exposure decreases susceptibility to gentamicin and other aminoglycosides in Listeria monocytogenes. Antimicrob Agents Chemother 2011; 55:4064-71. [PMID: 21746948 DOI: 10.1128/aac.00460-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human food-borne pathogen Listeria monocytogenes is capable of persisting in food processing plants despite cleaning and sanitation and is likely exposed to sublethal biocide concentrations. This could potentially affect susceptibility of the bacterium to biocides and other antimicrobial agents. The purpose of the present study was to determine if sublethal biocide concentrations affected antibiotic susceptibility in L. monocytogenes. Exposure of L. monocytogenes strains EGD and N53-1 to sublethal concentrations of Incimaxx DES (containing peroxy acids and hydrogen peroxide) and Triquart Super (containing quaternary ammonium compound) in four consecutive cultures did not alter the frequency of antibiotic-tolerant isolates, as determined by plating on 2× the MIC for a range of antibiotics. Exposure of eight strains of L. monocytogenes to 1 and 4 μg/ml triclosan did not alter triclosan sensitivity. However, all eight strains became resistant to gentamicin (up to 16-fold increase in MIC) after exposure to sublethal triclosan concentrations. Gentamicin-resistant isolates of strains N53-1 and 4446 were also resistant to other aminoglycosides, such as kanamycin, streptomycin, and tobramycin. Gentamicin resistance remained at a high level also after five subcultures without triclosan or gentamicin. Aminoglycoside resistance can be caused by mutations in the target site, the 16S rRNA gene. However, such mutations were not detected in the N53-1-resistant isolates. A combination of gentamicin and ampicillin is commonly used in listeriosis treatment. The triclosan-induced resistance is, hence, of great concern. Further investigations are needed to determine the molecular mechanisms underlying the effect of triclosan.
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Hesketh A, Hill C, Mokhtar J, Novotna G, Tran N, Bibb M, Hong HJ. Genome-wide dynamics of a bacterial response to antibiotics that target the cell envelope. BMC Genomics 2011; 12:226. [PMID: 21569315 PMCID: PMC3123327 DOI: 10.1186/1471-2164-12-226] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 05/11/2011] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND A decline in the discovery of new antibacterial drugs, coupled with a persistent rise in the occurrence of drug-resistant bacteria, has highlighted antibiotics as a diminishing resource. The future development of new drugs with novel antibacterial activities requires a detailed understanding of adaptive responses to existing compounds. This study uses Streptomyces coelicolor A3(2) as a model system to determine the genome-wide transcriptional response following exposure to three antibiotics (vancomycin, moenomycin A and bacitracin) that target distinct stages of cell wall biosynthesis. RESULTS A generalised response to all three antibiotics was identified which involves activation of transcription of the cell envelope stress sigma factor σ(E), together with elements of the stringent response, and of the heat, osmotic and oxidative stress regulons. Attenuation of this system by deletion of genes encoding the osmotic stress sigma factor σ(B) or the ppGpp synthetase RelA reduced resistance to both vancomycin and bacitracin. Many antibiotic-specific transcriptional changes were identified, representing cellular processes potentially important for tolerance to each antibiotic. Sensitivity studies using mutants constructed on the basis of the transcriptome profiling confirmed a role for several such genes in antibiotic resistance, validating the usefulness of the approach. CONCLUSIONS Antibiotic inhibition of bacterial cell wall biosynthesis induces both common and compound-specific transcriptional responses. Both can be exploited to increase antibiotic susceptibility. Regulatory networks known to govern responses to environmental and nutritional stresses are also at the core of the common antibiotic response, and likely help cells survive until any specific resistance mechanisms are fully functional.
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Affiliation(s)
- Andy Hesketh
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Chris Hill
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jehan Mokhtar
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Gabriela Novotna
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Ngat Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Mervyn Bibb
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Hee-Jeon Hong
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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Resistance and tolerance to tropodithietic acid, an antimicrobial in aquaculture, is hard to select. Antimicrob Agents Chemother 2011; 55:1332-7. [PMID: 21263047 DOI: 10.1128/aac.01222-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The antibacterial compound tropodithietic acid (TDA) is produced by bacteria of the marine Roseobacter clade and is thought to explain the fish probiotic properties of some roseobacters. The aim of the present study was to determine the antibacterial spectrum of TDA and the likelihood of development of TDA resistance. A bacterial extract containing 95% TDA was effective against a range of human-pathogenic bacteria, including both Gram-negative and Gram-positive bacteria. TDA was bactericidal against Salmonella enterica serovar Typhimurium SL1344 and Staphylococcus aureus NCTC 12493 and killed both growing and nongrowing cells. Several experimental approaches were used to select mutants resistant to TDA or subpopulations of strains with enhanced tolerance to TDA. No approach (single exposures to TDA extract administered via different methods, screening of a transposon library for resistant mutants, or prolonged exposure to incremental concentrations of TDA) resulted in resistant or tolerant strains. After more than 300 generations exposed to sub-MIC and MIC concentrations of a TDA-containing extract, strains tolerant to 2× the MIC of TDA for wild-type strains were selected, but the tolerance disappeared after one passage in medium without TDA extract. S. Typhimurium mutants with nonfunctional efflux pump and porin genes had the same TDA susceptibility as wild-type strains, suggesting that efflux pumps and porins are not involved in innate tolerance to TDA. TDA is a promising broad-spectrum antimicrobial in part due to the fact that enhanced tolerance is difficult to gain and that the TDA-tolerant phenotype appears to confer only low-level resistance and is very unstable.
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29
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Dorosz J, Gofman Y, Kolusheva S, Otzen D, Ben-Tal N, Nielsen NC, Jelinek R. Membrane interactions of novicidin, a novel antimicrobial peptide: phosphatidylglycerol promotes bilayer insertion. J Phys Chem B 2010; 114:11053-60. [PMID: 20690652 DOI: 10.1021/jp1052248] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Novicidin is an antimicrobial peptide derived from ovispirin, a cationic peptide which originated from the ovine cathelicidin SMAP-29. Novicidin, however, has been designed to minimize the cytotoxic properties of SMAP-29 and ovisipirin toward achieving potential therapeutic applications. We present an analysis of membrane interactions and lipid bilayer penetration of novicidin, using an array of biophysical techniques and biomimetic membrane assemblies, complemented by Monte Carlo (MC) simulations. The data indicate that novicidin interacts minimally with zwitterionic bilayers, accounting for its low hemolytic activity. Negatively charged phosphatidylglycerol, on the other hand, plays a significant role in initiating membrane binding of novicidin, and promotes peptide insertion into the interface between the lipid headgroups and the acyl chains. The significant insertion into bilayers containing negative phospholipids might explain the enhanced antibacterial properties of novicidin. Overall, this study highlights two distinct outcomes for membrane interactions of novicidin, and points to a combination between electrostatic attraction to the lipid/water interface and penetration into the subsurface lipid headgroups region as important determinants for the biological activity of novicidin.
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Affiliation(s)
- Jerzy Dorosz
- Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University, Beer Sheva 84105, Israel
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30
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Thomsen LE, Gottlieb CT, Gottschalk S, Wodskou TT, Kristensen HH, Gram L, Ingmer H. The heme sensing response regulator HssR in Staphylococcus aureus but not the homologous RR23 in Listeria monocytogenes modulates susceptibility to the antimicrobial peptide plectasin. BMC Microbiol 2010; 10:307. [PMID: 21122114 PMCID: PMC3001719 DOI: 10.1186/1471-2180-10-307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 12/01/2010] [Indexed: 11/15/2022] Open
Abstract
Background Host defence peptides (HDPs), also known as antimicrobial peptides (AMPs), have emerged as potential new therapeutics and their antimicrobial spectrum covers a wide range of target organisms. However, the mode of action and the genetics behind the bacterial response to HDPs is incompletely understood and such knowledge is required to evaluate their potential as antimicrobial therapeutics. Plectasin is a recently discovered HDP active against Gram-positive bacteria with the human pathogen, Staphylococcus aureus (S. aureus) being highly susceptible and the food borne pathogen, Listeria monocytogenes (L. monocytogenes) being less sensitive. In the present study we aimed to use transposon mutagenesis to determine the genetic basis for S. aureus and L. monocytogenes susceptibility to plectasin. Results In order to identify genes that provide susceptibility to plectasin we constructed bacterial transposon mutant libraries of S. aureus NCTC8325-4 and L. monocytogenes 4446 and screened for increased resistance to the peptide. No resistant mutants arose when L. monocytogenes was screened on plates containing 5 and 10 fold Minimal Inhibitory Concentration (MIC) of plectasin. However, in S. aureus, four mutants with insertion in the heme response regulator (hssR) were 2-4 fold more resistant to plectasin as compared to the wild type. The hssR mutation also enhanced resistance to the plectasin-like defensin eurocin, but not to other classes of HDPs or to other stressors tested. Addition of plectasin did not influence the expression of hssR or hrtA, a gene regulated by HssR. The genome of L. monocytogenes LO28 encodes a putative HssR homologue, RR23 (in L. monocytogenes EGD-e lmo2583) with 48% identity to the S. aureus HssR, but a mutation in the rr23 gene did not change the susceptibility of L. monocytogenes to plectasin. Conclusions S. aureus HssR, but not the homologue RR23 from L. monocytogenes, provides susceptibility to the defensins plectasin and eurocin. Our data suggest that a functional difference between response regulators HssR and RR23 is responsible for the difference in plectasin susceptibility observed between S. aureus and L. monocytogenes.
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Affiliation(s)
- Line E Thomsen
- Department of Veterinary Disease Biology, University of Copenhagen, DK-1870 Frederiksberg C, Denmark.
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Schuppler M, Loessner MJ. The Opportunistic Pathogen Listeria monocytogenes: Pathogenicity and Interaction with the Mucosal Immune System. Int J Inflam 2010; 2010:704321. [PMID: 21188219 PMCID: PMC3003996 DOI: 10.4061/2010/704321] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/01/2010] [Indexed: 12/22/2022] Open
Abstract
Listeria monocytogenes is an opportunistic foodborne pathogen causing listeriosis, an often fatal infection leading to meningitis, sepsis, or infection of the fetus and abortion in susceptible individuals. It was recently found that the bacterium can also cause acute, self-limiting febrile gastroenteritis in healthy individuals. In the intestinal tract, L. monocytogenes penetrates the mucosa directly via enterocytes, or indirectly via invasion of Peyer's patches. Animal models for L. monocytogenes infection have provided many insights into the mechanisms of pathogenesis, and the development of new model systems has allowed the investigation of factors that influence adaptation to the gastrointestinal environment as well as adhesion to and invasion of the intestinal mucosa. The mucosal surfaces of the gastrointestinal tract are permanently exposed to an enormous antigenic load derived from the gastrointestinal microbiota present in the human bowel. The integrity of the important epithelial barrier is maintained by the mucosal immune system and its interaction with the commensal flora via pattern recognition receptors (PRRs). Here, we discuss recent advances in our understanding of the interaction of L. monocytogenes with the host immune system that triggers the antibacterial immune responses on the mucosal surfaces of the human gastrointestinal tract.
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Affiliation(s)
- Markus Schuppler
- Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstraße 7, 8092 Zurich, Switzerland
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Andersen AS, Sandvang D, Schnorr KM, Kruse T, Neve S, Joergensen B, Karlsmark T, Krogfelt KA. A novel approach to the antimicrobial activity of maggot debridement therapy. J Antimicrob Chemother 2010; 65:1646-54. [PMID: 20542901 PMCID: PMC2904663 DOI: 10.1093/jac/dkq165] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Objectives Commercially produced sterile green bottle fly Lucilia sericata maggots are successfully employed by practitioners worldwide to clean a multitude of chronic necrotic wounds and reduce wound bacterial burdens during maggot debridement therapy (MDT). Secretions from the maggots exhibit antimicrobial activity along with other activities beneficial for wound healing. With the rise of multidrug-resistant bacteria, new approaches to identifying the active compounds responsible for the antimicrobial activity within this treatment are imperative. Therefore, the aim of this study was to use a novel approach to investigate the output of secreted proteins from the maggots under conditions mimicking clinical treatments. Methods cDNA libraries constructed from microdissected salivary glands and whole maggots, respectively, were treated with transposon-assisted signal trapping (TAST), a technique selecting for the identification of secreted proteins. Several putative secreted components of insect immunity were identified, including a defensin named lucifensin, which was produced recombinantly as a Trx-fusion protein in Escherichia coli, purified using immobilized metal affinity chromatography and reverse-phase HPLC, and tested in vitro against Gram-positive and Gram-negative bacterial strains. Results Lucifensin was active against Staphylococcus carnosus, Streptococcus pyogenes and Streptococcus pneumoniae (MIC 2 mg/L), as well as Staphylococcus aureus (MIC 16 mg/L). The peptide did not show antimicrobial activity towards Gram-negative bacteria. The MIC of lucifensin for the methicillin-resistant S. aureus and glycopeptide-intermediate S. aureus isolates tested ranged from 8 to >128 mg/L. Conclusions The TAST results did not reveal any highly secreted compounds with putative antimicrobial activity, implying an alternative antimicrobial activity of MDT. Lucifensin showed antimicrobial activities comparable to other defensins and could have potential as a future drug candidate scaffold, for redesign for other applications besides the topical treatment of infected wounds.
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Affiliation(s)
- Anders S Andersen
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen S, Denmark
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Fazakerley J, Crossley J, McEwan N, Carter S, Nuttall T. In vitro antimicrobial efficacy of β-defensin 3 against Staphylococcus pseudintermedius isolates from healthy and atopic canine skin. Vet Dermatol 2010; 21:463-8. [PMID: 20492622 DOI: 10.1111/j.1365-3164.2010.00893.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
β-Defensins (BDs) are highly conserved antimicrobial peptides important in innate defence against bacteria. β-Defensin 3 has a specific role in protecting the skin. This study quantified the minimal inhibitory concentration (MIC) of human (h)BD3 against Staphylococcus pseudintermedius isolates from atopic and healthy dogs. Single colony isolates (1 × 10(5) colony-forming units/mL log phase) were cultured with doubling dilutions of hBD3 in sodium phosphate buffer from 0.8 to 50 μg/mL at 37 °C for 2 h, before adding 100 μL of tryptone soy broth and incubating for a further 20 h. Bacterial growth was assessed as the mean optical density at 540 nm corrected for background. The median MIC was 12.5 μg hBD3/mL (range 3.125-25 μg/mL; n=22). Forty-five percent of the isolates were inhibited at ≤ 6.25 μg hBD3/mL, and 90% were inhibited at ≤ 12.5 μg hBD3/mL. Bacterial growth was not inhibited at ≤ 1.6 μg hBD3/mL. There were no significant differences in the inhibition by hBD3 of isolates from atopic (median MIC 12.5 μg/mL, range 6.25-25 μg/mL, n=14) and healthy dogs (median MIC 9.4 μg/mL, range 3.125-12.5 μg/mL, n = 8); from noninfected colonized sites (median MIC 12.5 μg/mL, range 3.125-25 μg/mL, n=16) and infected lesions (median MIC 9.4 μg/mL, range 6.25-12.5 μg/mL, n=6); or between sample sites (nose median MIC 12.5 μg/mL, range 6.25-25 μg/mL, n=5; perineum median MIC 12.5 μg/mL, range 3.125-25 μg/mL, n=7; ear median MIC 6.25 μg/mL, range 6.25-12.5 μg/mL, n=4; lesions median MIC 9.4 μg/mL, range 6.25-12.5 μg/mL, n=6). In conclusion, hBD3 inhibited the growth of canine S. pseudintermedius isolates in vitro irrespective of origin.
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Affiliation(s)
- Jennifer Fazakerley
- The University of Liverpool School of Veterinary Science, Leahurst Campus, Neston, Cheshire CH64 7TE, UK
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Fantner GE, Barbero RJ, Gray DS, Belcher AM. Kinetics of antimicrobial peptide activity measured on individual bacterial cells using high-speed atomic force microscopy. NATURE NANOTECHNOLOGY 2010; 5:280-5. [PMID: 20228787 PMCID: PMC3905601 DOI: 10.1038/nnano.2010.29] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 02/03/2010] [Indexed: 05/15/2023]
Abstract
Observations of real-time changes in living cells have contributed much to the field of cellular biology. The ability to image whole, living cells with nanometre resolution on a timescale that is relevant to dynamic cellular processes has so far been elusive. Here, we investigate the kinetics of individual bacterial cell death using a novel high-speed atomic force microscope optimized for imaging live cells in real time. The increased time resolution (13 s per image) allows the characterization of the initial stages of the action of the antimicrobial peptide CM15 on individual Escherichia coli cells with nanometre resolution. Our results indicate that the killing process is a combination of a time-variable incubation phase (which takes seconds to minutes to complete) and a more rapid execution phase.
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Affiliation(s)
- Georg E Fantner
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Kotarsky K, Sitnik KM, Stenstad H, Kotarsky H, Schmidtchen A, Koslowski M, Wehkamp J, Agace WW. A novel role for constitutively expressed epithelial-derived chemokines as antibacterial peptides in the intestinal mucosa. Mucosal Immunol 2010; 3:40-8. [PMID: 19812544 DOI: 10.1038/mi.2009.115] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intestinal-derived chemokines have a central role in orchestrating immune cell influx into the normal and inflamed intestine. Here, we identify the chemokine CCL6 as one of the most abundant chemokines constitutively expressed by both murine small intestinal and colonic epithelial cells. CCL6 protein localized to crypt epithelial cells, was detected in the gut lumen and reached high concentrations at the mucosal surface. Its expression was further enhanced in the small intestine following in vivo administration of LPS or after stimulation of the small intestinal epithelial cell line, mIC(c12), with IFNgamma, IL-4 or TNFalpha. Recombinant- and intestinal-derived CCL6 bound to a subset of the intestinal microflora and displayed antibacterial activity. Finally, the human homologs to CCL6, CCL14 and CCL15 were also constitutively expressed at high levels in human intestinal epithelium, were further enhanced in inflammatory bowel disease and displayed similar antibacterial activity. These findings identify a novel role for constitutively expressed, epithelial-derived chemokines as antimicrobial peptides in the intestinal mucosa.
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Affiliation(s)
- K Kotarsky
- Immunology Section, Department of Experimental Medical Sciences, Lund University, Lund, Sweden.
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Abstract
One of the most significant advances in medical history is the discovery and development of antibiotics, which in the middle of last century was flourishing and appeared to be the ultimate solution to the treatment of life-threatening human bacterial diseases. However, lately there has been a huge decline in the rate of discovery of new antimicrobial intervention strategies in parallel with an increasing incidence of multidrug-resistant pathogens; if these circumstances do not change we will continue to approach the end of the antibiotic era. Facing this dark future, scientists are considering new strategies for intervention tailored around the appropriate (selective) stimulation of the host's immune system, and particularly rapid acting innate immunity, as an alternative to direct targeting of microbial pathogens. One recent player in such an immunomodulatory strategy is the naturally occurring host defence peptides (HDP) and their synthetic innate defence regulator (IDR) analogues. In this chapter, we will discuss the potential therapeutic use of HDPs and IDRs as immunomodulatory agents.
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Affiliation(s)
- Håvard Jenssen
- Department of Science, Systems, and Models, Roskilde University, Roskilde, Denmark
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Therapeutic approaches using host defence peptides to tackle herpes virus infections. Viruses 2009; 1:939-64. [PMID: 21994576 PMCID: PMC3185547 DOI: 10.3390/v1030939] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 10/11/2009] [Accepted: 11/16/2009] [Indexed: 01/07/2023] Open
Abstract
One of the most common viral infections in humans is caused by herpes simplex virus (HSV). It can easily be treated with nucleoside analogues (e.g., acyclovir), but resistant strains are on the rise. Naturally occurring antimicrobial peptides have been demonstrated to possess antiviral activity against HSV. New evidence has also indicated that these host defence peptides are able to selectively stimulate the innate immune system to fight of infections. This review will focus on the anti-HSV activity of such peptides (both natural and synthetic), describe their mode of action and their clinical potential.
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Sleator RD, Watson D, Hill C, Gahan CGM. The interaction between Listeria monocytogenes and the host gastrointestinal tract. MICROBIOLOGY-SGM 2009; 155:2463-2475. [PMID: 19542009 DOI: 10.1099/mic.0.030205-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Listeria monocytogenes is a ubiquitous bacterium that causes significant foodborne disease with high mortality rates in immunocompromised adults. In pregnant women foodborne infection can give rise to infection of the fetus resulting in miscarriage. In addition, the bacterium has recently been demonstrated to cause localized gastrointestinal symptoms, predominantly in immunocompetent individuals. The murine model of systemic L. monocytogenes infection has provided numerous insights into the mechanisms of pathogenesis of this organism. However, recent application of transcriptomic and proteomic approaches as well as the development of new model systems has allowed a focus upon factors that influence adaptation to gastrointestinal environments and adhesion to and invasion of the gastrointestinal mucosa. In addition, the availability of a large number of complete L. monocytogenes genome sequences has permitted inter-strain comparisons and the identification of factors that may influence the emergence of 'epidemic' phenotypes. Here we review some of the exciting recent developments in the analysis of the interaction between L. monocytogenes and the host gastrointestinal tract.
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Affiliation(s)
- Roy D Sleator
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Debbie Watson
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Colin Hill
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Cormac G M Gahan
- School of Pharmacy, University College Cork, Cork, Ireland
- Department of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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