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Chan SJW, Zhu JY, Mia Soh WW, Bazan GC. Real-Time Monitoring of Mitochondrial Damage Using Conjugated Oligoelectrolytes. J Am Chem Soc 2024; 146:660-667. [PMID: 38131111 DOI: 10.1021/jacs.3c10531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Conjugated oligoelectrolytes (COEs) comprise a class of fluorescent reporters with tunable optical properties and lipid bilayer affinity. These molecules have proven effective in a range of bioimaging applications; however, their use in characterizing specific subcellular structures remains restricted. Such capabilities would broaden COE applications to understand cellular dysfunction, cell communication, and the targets of different pharmaceutical agents. Here, we disclose a novel COE derivative, COE-CN, which enables the visualization of mitochondria, including morphological changes and lysosomal fusion upon treatment with depolarizing agents. COE-CN is characterized by the presence of imidazolium solubilizing groups and an optically active cyanovinyl-linked distyrylbenzene core with intramolecular charge-transfer characteristics. Our current understanding is that the relatively shorter molecular length of COE-CN leads to weaker binding within lipid bilayer membranes, which allows sampling of internal cellular structures and ultimately to different localization relative to elongated COEs. As a means of practical demonstration, COE-CN can be used to diagnose cells with damaged mitochondria via flow cytometry. Coupled with an elongated COE that does not translocate upon depolarization, changes in ratiometric fluorescence intensity can be used to monitor mitochondrial membrane potential disruption, demonstrating the potential for use in diagnostic assays.
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Affiliation(s)
- Samuel J W Chan
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Ji-Yu Zhu
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Wilson Wee Mia Soh
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Guillermo C Bazan
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117544, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore
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2
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Mansour N, Mehanna S, Bodman-Smith K, Daher CF, Khnayzer RS. A Ru(II)-Strained Complex with 2,9-Diphenyl-1,10-phenanthroline Ligand Induces Selective Photoactivatable Chemotherapeutic Activity on Human Alveolar Carcinoma Cells via Apoptosis. Pharmaceuticals (Basel) 2023; 17:50. [PMID: 38256884 PMCID: PMC10819265 DOI: 10.3390/ph17010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 01/24/2024] Open
Abstract
[Ru(bipy)2(dpphen)]Cl2 (where bipy = 2,2'-bipyridine and dpphen = 2,9-diphenyl-1,10-phenanthroline) (complex 1) is a sterically strained compound that exhibits promising in vitro photocytotoxicity on an array of cell lines. Since lung adenocarcinoma cancer remains the most common lung cancer and the leading cause of cancer deaths, the current study aims to evaluate the plausible effect and uptake of complex 1 on human alveolar carcinoma cells (A549) and mesenchymal stem cells (MSC), and assess its cytotoxicity in vitro while considering its effect on cell morphology, membrane integrity and DNA damage. MSC and A549 cells showed similar rates of complex 1 uptake with a plateau at 12 h. Upon photoactivation, complex 1 exhibited selective, potent anticancer activity against A549 cells with phototoxicity index (PI) values of 16, 25 and 39 at 24, 48 and 72 h, respectively. This effect was accompanied by a significant increase in A549-cell rounding and detachment, loss of membrane integrity and DNA damage. Flow cytometry experiments confirmed that A549 cells undergo apoptosis when treated with complex 1 followed by photoactivation. In conclusion, this present study suggests that complex 1 might be a promising candidate for photochemotherapy with photoproducts that possess selective anticancer effects in vitro. These results are encouraging to probe the potential activity of this complex in vivo.
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Affiliation(s)
- Najwa Mansour
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon; (N.M.); (S.M.); (C.F.D.)
| | - Stephanie Mehanna
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon; (N.M.); (S.M.); (C.F.D.)
| | - Kikki Bodman-Smith
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK;
| | - Costantine F. Daher
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon; (N.M.); (S.M.); (C.F.D.)
| | - Rony S. Khnayzer
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon; (N.M.); (S.M.); (C.F.D.)
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3
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Mustroph H, Horobin RW. Classification and naming of polymethine dyes used as staining agents for microscopy. A short guide for biomedical investigators. Biotech Histochem 2023; 98:545-553. [PMID: 37877362 DOI: 10.1080/10520295.2023.2263837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023] Open
Abstract
The scientific literature contains many accounts of application of polymethine dyes, including cyanine dyes, as imaging agents, i.e., "biological stains," for microscopic investigation of biological materials. Currently, many such dyes are used as probes for living cells, i.e., "fluorescent probes." Polymethine dyes are defined here by two criteria. First, they possess a conjugated chain of (2n + 1) sp2-hybridized carbon atoms that connect a terminal π-electron-accepting (π-electron withdrawing) group with a terminal π-electron-donating group. Second, they have an odd number (2n + 3) of π-centers and an even number (2n + 4) of π-electrons in this chain, where n equals the number of -CR2=CR3- groups, usually vinylene groups -CH=CH-. Commercialization of diverse chemical types of many polymethine dyes has been attempted. The dyes that have achieved wide application, however, are limited in number and it is these dyes that are emphasized here. Because these polymethine dyes sometimes have been described by confusing, and sometimes confused, names, we clarify here the chemical categories and names of such dyes for the nonchemist, biomedical end user of such imaging agents. Nevertheless, the nomenclature presented here is not intended to replace the traditional "chromophore" categories of dyestuff chemistry, because the latter are held in place both by wide usage and by venerable authorities, such as the Colour Index.
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Affiliation(s)
| | - Richard W Horobin
- Chemical Biology, School of Chemistry, The University of Glasgow, Glasgow, Scotland, UK
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4
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Ernst P, Kim S, Yang Z, Liu XM, Zhou L. Characterization of the far-red fluorescent probe MitoView 633 for dynamic mitochondrial membrane potential measurement. Front Physiol 2023; 14:1257739. [PMID: 37936577 PMCID: PMC10627182 DOI: 10.3389/fphys.2023.1257739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/13/2023] [Indexed: 11/09/2023] Open
Abstract
Introduction: MitoView 633, a far-red fluorescent dye, exhibits the ability to accumulate within mitochondria in a membrane potential-dependent manner, as described by the Nernst equation. This characteristic renders it a promising candidate for bioenergetics studies, particularly as a robust indicator of mitochondrial membrane potential (DYm). Despite its great potential, its utility in live cell imaging has not been well characterized. Methods: This study seeks to characterize the spectral properties of MitoView 633 in live cells and evaluate its mitochondrial staining, resistance to photobleaching, and dynamics during DYm depolarization. The co-staining and imaging of MitoView 633 with other fluorophores such as MitoSOX Red and Fluo-4 AM were also examined in cardiomyocytes using confocal microscopy. Results and Discussion: Spectrum analysis showed that MitoView 633 emission could be detected at 660 ± 50 nm, and exhibited superior thermal stability compared to tetramethylrhodamine methyl ester (TMRM), a commonly used DYm indicator, which emits at 605 ± 25 nm. Confocal imaging unequivocally illustrated MitoView 633's specific localization within the mitochondrial matrix, corroborated by its colocalization with MitoTracker Green, a well-established mitochondrial marker. Furthermore, our investigation revealed that MitoView 633 exhibited minimal photobleaching at the recommended in vitro concentrations. Additionally, the dynamics of MitoView 633 fluoresce during carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP, a mitochondrial uncoupler)-induced DYm depolarization mirrored that of TMRM. Importantly, MitoView 633 demonstrated compatibility with co-staining alongside MitoSOX Red and Fluo-4 AM, enabling concurrent monitoring of DYm, mitochondrial ROS, and cytosolic Ca2+ in intact cells. Conclusion: These findings collectively underscore MitoView 633 as a superb molecular probe for the singular or combined assessment of DYm and other indicators in live cell imaging applications.
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Affiliation(s)
- Patrick Ernst
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Seulhee Kim
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Zengqiao Yang
- Department of Surgery, The Ohio State University, Columbus, OH, United States
| | - Xiaoguang Margaret Liu
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, United States
| | - Lufang Zhou
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Department of Surgery, The Ohio State University, Columbus, OH, United States
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Yang J, Li Z, Zhang D, Yamaguchi Y, Xiao W. Direct count of fluorescent microspheres in a microfluidic chip based on the capillary electrophoresis method. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023. [PMID: 37334474 DOI: 10.1039/d3ay00710c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Fluorescent microspheres (FMs) are tiny particles with special functions that are widely employed in biological research. Counting of microscale FMs is a great challenge by capillary electrophoresis. Herein we developed a method to count 2 μm FMs based on a microfluidic chip with a gradual change in inner size. Such a microfluidic chip can inhibit sample blocking at the inlet of the capillary. The results showed that FMs migrated in the wide part of the microchannel side by side, and then passed through the narrow part one by one. There was a linear relationship between the number of peaks in the electropherogram and concentration of FMs if they were running in the microchannel for more than 20 min. A high separation voltage may lead to aggregation of FMs in the microchannels, and about 2 × 104 FMs can be counted within 30 min by this microfluidic chip.
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Affiliation(s)
- Jing Yang
- Anhui Sanlian University, Hefei 230000, China
| | - Zhenqing Li
- Engineering Research Center of Optical Instrument and System, Key Lab of Optical Instruments and Equipment for Medical Engineering, Ministry of Education, Shanghai Key Lab of Modern Optical System, Shanghai Environmental Biosafety Instruments and Equipment Engineering Technology Research Center, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Dawei Zhang
- Engineering Research Center of Optical Instrument and System, Key Lab of Optical Instruments and Equipment for Medical Engineering, Ministry of Education, Shanghai Key Lab of Modern Optical System, Shanghai Environmental Biosafety Instruments and Equipment Engineering Technology Research Center, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Yoshinori Yamaguchi
- Picotecbio-Waseda Joint Research Lab, Faculty of Science and Engineering, Waseda University, Saitama, 367-0035, Japan.
| | - Wen Xiao
- Department of Pediatric Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Shanghai 200011, China.
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6
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Timofeeva L, Bondarenko G, Nikitushkin V, Simonova Y, Topchiy M, Eremenko I, Shleeva M, Mulyukin A, Kaprelyants A. On the molecular mechanism of nonspecific antimicrobial action of protonated diallylammonium polymers on mycobacterial cells. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Soret M, Bouchendhomme T, Cleach J, Jouy N, Crola Da Silva C, Devin A, Grard T, Lencel P. Measurement of fish freshness: Flow cytometry analysis of isolated muscle mitochondria. Food Chem 2022; 373:131690. [PMID: 34865931 DOI: 10.1016/j.foodchem.2021.131690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 01/26/2023]
Abstract
Mitochondria are real sensors of the physiological status of tissues. After the death of an animal, they maintain physiological activity for several days. This activity is highly dependent on the availability of nutrients in the tissue. In this study, flow cytometry was used to measure the membrane potential of mitochondria isolated from European seabass (Dicentrarchus labrax) red muscle stored in ice for seven days in order to characterize fish freshness. Two probes, TMRM and Rhodamine 123, were used to measure mitochondrial potential. During the first few days (D0 to D3), isolated mitochondria maintained high potential, and then lost their potential (from D3 to D5), but were always re-polarizable after addition of substrates (glutamate, malate and succinate). From D7, the mitochondria were more strongly depolarized and were difficult to repolarize by the substrates. Using flow cytometry, we demonstrated that mitochondria were an excellent marker to confirm seabass freshness.
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Affiliation(s)
- Méline Soret
- Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, Institut Charles Viollette, USC ANSES, INRAE, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200 Boulogne-sur-Mer, France.
| | - Tiffanie Bouchendhomme
- Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, Institut Charles Viollette, USC ANSES, INRAE, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200 Boulogne-sur-Mer, France.
| | - Jérôme Cleach
- Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, Institut Charles Viollette, USC ANSES, INRAE, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200 Boulogne-sur-Mer, France.
| | - Nathalie Jouy
- Univ. Lille, Bio Imaging Center Lille, Lille, F-59000, France.
| | - Claire Crola Da Silva
- Univ. Claude Bernard Lyon 1, CarMeN Laboratory, INSERM U1060, INRAe, INSA, F-69500 Bron, France.
| | - Anne Devin
- UMR CNRS 5095 Institut de biochimie et génétique cellulaires (IBGC), F-33077 Bordeaux, France.
| | - Thierry Grard
- Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, Institut Charles Viollette, USC ANSES, INRAE, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200 Boulogne-sur-Mer, France.
| | - Philippe Lencel
- Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, Institut Charles Viollette, USC ANSES, INRAE, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200 Boulogne-sur-Mer, France.
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8
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Li W, Lin F, Hung A, Barlow A, Sani MA, Paolini R, Singleton W, Holden J, Hossain MA, Separovic F, O'Brien-Simpson NM, Wade JD. Enhancing proline-rich antimicrobial peptide action by homodimerization: influence of bifunctional linker. Chem Sci 2022; 13:2226-2237. [PMID: 35310489 PMCID: PMC8864714 DOI: 10.1039/d1sc05662j] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/16/2022] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial peptides (AMPs) are host defense peptides, and unlike conventional antibiotics, they possess potent broad spectrum activities and, induce little or no antimicrobial resistance. They are attractive lead molecules for rational development to improve their therapeutic index. Our current studies examined dimerization of the de novo designed proline-rich AMP (PrAMP), Chex1-Arg20 hydrazide, via C-terminal thiol addition to a series of bifunctional benzene or phenyl tethers to determine the effect of orientation of the peptides and linker length on antimicrobial activity. Antibacterial assays confirmed that dimerization per se significantly enhances Chex1-Arg20 hydrazide action. Greatest advantage was conferred using perfluoroaromatic linkers (tetrafluorobenzene and octofluorobiphenyl) with the resulting dimeric peptides 6 and 7 exhibiting potent action against Gram-negative bacteria, especially the World Health Organization's critical priority-listed multidrug-resistant (MDR)/extensively drug-resistant (XDR) Acinetobacter baumannii as well as preformed biofilms. Mode of action studies indicated these lead PrAMPs can interact with both outer and inner bacterial membranes to affect the membrane potential and stress response. Additionally, 6 and 7 possess potent immunomodulatory activity and neutralise inflammation via nitric oxide production in macrophages. Molecular dynamics simulations of adsorption and permeation mechanisms of the PrAMP on a mixed lipid membrane bilayer showed that a rigid, planar tethered dimer orientation, together with the presence of fluorine atoms that provide increased bacterial membrane interaction, is critical for enhanced dimer activity. These findings highlight the advantages of use of such bifunctional tethers to produce first-in-class, potent PrAMP dimers against MDR/XDR bacterial infections.
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Affiliation(s)
- Wenyi Li
- The Bio21 Institute of Molecular Science and Biotechnology Australia
- Melbourne Dental School, Centre for Oral Health Research Australia
| | - Feng Lin
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Australia
| | - Andrew Hung
- School of Science, RMIT University Australia
| | - Anders Barlow
- Materials Characterization and Fabrication Platform Australia
| | - Marc-Antoine Sani
- The Bio21 Institute of Molecular Science and Biotechnology Australia
- School of Chemistry, University of Melbourne Victoria 3010 Australia
| | - Rita Paolini
- Melbourne Dental School, Centre for Oral Health Research Australia
| | | | - James Holden
- Melbourne Dental School, Centre for Oral Health Research Australia
| | - Mohammed Akhter Hossain
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Australia
- School of Chemistry, University of Melbourne Victoria 3010 Australia
| | - Frances Separovic
- The Bio21 Institute of Molecular Science and Biotechnology Australia
- School of Chemistry, University of Melbourne Victoria 3010 Australia
| | - Neil M O'Brien-Simpson
- The Bio21 Institute of Molecular Science and Biotechnology Australia
- Melbourne Dental School, Centre for Oral Health Research Australia
| | - John D Wade
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Australia
- School of Chemistry, University of Melbourne Victoria 3010 Australia
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9
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Oberpaul M, Brinkmann S, Marner M, Mihajlovic S, Leis B, Patras MA, Hartwig C, Vilcinskas A, Hammann PE, Schäberle TF, Spohn M, Glaeser J. Combination of high-throughput microfluidics and FACS technologies to leverage the numbers game in natural product discovery. Microb Biotechnol 2022; 15:415-430. [PMID: 34165868 PMCID: PMC8867984 DOI: 10.1111/1751-7915.13872] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/17/2021] [Accepted: 06/06/2021] [Indexed: 12/21/2022] Open
Abstract
High-throughput platforms facilitating screening campaigns of environmental samples are needed to discover new products of natural origin counteracting the spreading of antimicrobial resistances constantly threatening human and agricultural health. We applied a combination of droplet microfluidics and fluorescence-activated cell sorting (FACS)-based technologies to access and assess a microbial environmental sample. The cultivation performance of our microfluidics workflow was evaluated in respect to the utilized cultivation media by Illumina amplicon sequencing of a pool of millions of droplets, respectively. This enabled the rational selection of a growth medium supporting the isolation of microbial diversity from soil (five phyla affiliated to 57 genera) including a member of the acidobacterial subgroup 1 (genus Edaphobacter). In a second phase, the entire diversity covered by 1071 cultures was used for an arrayed bioprospecting campaign, resulting in > 6000 extracts tested against human pathogens and agricultural pests. After redundancy curation by using a combinatorial chemical and genomic fingerprinting approach, we assigned the causative agents present in the extracts. Utilizing UHPLC-QTOF-MS/MS-guided fractionation and microplate-based screening assays in combination with molecular networking the production of bioactive ionophorous macrotetrolides, phospholipids, the cyclic lipopetides massetolides E, F, H and serratamolide A and many derivatives thereof was shown.
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Affiliation(s)
- Markus Oberpaul
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Stephan Brinkmann
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Michael Marner
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Sanja Mihajlovic
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Benedikt Leis
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Maria A. Patras
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Christoph Hartwig
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
| | - Andreas Vilcinskas
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
- Institute for Insect BiotechnologyJustus‐Liebig‐University‐GiessenGiessen35392Germany
| | | | - Till F. Schäberle
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
- Institute for Insect BiotechnologyJustus‐Liebig‐University‐GiessenGiessen35392Germany
- German Center for Infection Research (DZIF), Partner Site Giessen‐Marburg‐LangenGiessen35392Germany
| | - Marius Spohn
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for BioresourcesGiessen35392Germany
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10
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Klemz A, Wildner F, Tütüncü E, Gerevich Z. Regulation of Hippocampal Gamma Oscillations by Modulation of Intrinsic Neuronal Excitability. Front Neural Circuits 2022; 15:778022. [PMID: 35177966 PMCID: PMC8845518 DOI: 10.3389/fncir.2021.778022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
Ion channels activated around the subthreshold membrane potential determine the likelihood of neuronal firing in response to synaptic inputs, a process described as intrinsic neuronal excitability. Long-term plasticity of chemical synaptic transmission is traditionally considered the main cellular mechanism of information storage in the brain; however, voltage- and calcium-activated channels modulating the inputs or outputs of neurons are also subjects of plastic changes and play a major role in learning and memory formation. Gamma oscillations are associated with numerous higher cognitive functions such as learning and memory, but our knowledge of their dependence on intrinsic plasticity is by far limited. Here we investigated the roles of potassium and calcium channels activated at near subthreshold membrane potentials in cholinergically induced persistent gamma oscillations measured in the CA3 area of rat hippocampal slices. Among potassium channels, which are responsible for the afterhyperpolarization in CA3 pyramidal cells, we found that blockers of SK (KCa2) and KV7.2/7.3 (KCNQ2/3), but not the BK (KCa1.1) and IK (KCa3.1) channels, increased the power of gamma oscillations. On the contrary, activators of these channels had an attenuating effect without affecting the frequency. Pharmacological blockade of the low voltage-activated T-type calcium channels (CaV3.1–3.3) reduced gamma power and increased the oscillation peak frequency. Enhancement of these channels also inhibited the peak power without altering the frequency of the oscillations. The presented data suggest that voltage- and calcium-activated ion channels involved in intrinsic excitability strongly regulate the power of hippocampal gamma oscillations. Targeting these channels could represent a valuable pharmacological strategy against cognitive impairment.
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11
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Schulte M, Hensel M. Flow Cytometry-Based Single Cell Analyses of Bacterial Adaptation to Intracellular Environments. Methods Mol Biol 2022; 2427:105-117. [PMID: 35619029 DOI: 10.1007/978-1-0716-1971-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Since decades, flow cytometry (FC) is a powerful technique to perform single cell analyses with high accuracy and throughput. Moreover, FC is the method of choice to study bacterial cell heterogeneity and complements single-cell imaging techniques. The complex experimental approaches for FC sample preparation and the subsequent FC adjustment and gating strategy demand careful considerations to be successful when analyzing complex microbial populations, especially when liberated populations of intracellular bacterial pathogens, or bacterial pathogens inside intact host cells are analyzed. Here, we provide a set of experimental protocols for FC sample preparation of (1) in vitro cultured bacterial cells, (2) liberated intracellular bacteria from host cells, or (3) preparation of intact infected phagocytic or epithelial cells commonly used as host cells in infection biology. Since sample preparation, cytometer adjustment, and gating strategy are essential for experimental success, we aim to provide our expertise to support application of FC by other researchers.
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Affiliation(s)
- Marc Schulte
- Abteilung Mikrobiologie and CellNanOs-Center of Cellular Nanoanalytics Osnabrück, Fachbereich Biologie/Chemie, Universität Osnabrück Barbarastr, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie and CellNanOs-Center of Cellular Nanoanalytics Osnabrück, Fachbereich Biologie/Chemie, Universität Osnabrück Barbarastr, Osnabrück, Germany.
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12
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Desvals A, Fortino M, Lefebvre C, Rogier J, Michelin C, Alioui S, Rousset E, Pedone A, Lemercier G, Hoffmann N. Synthesis and characterization of polymethine dyes carrying thiobarbituric and carboxylic acid moieties. NEW J CHEM 2022. [DOI: 10.1039/d2nj00684g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymethine dyes are prepared using a convenient synthesis and characterized by physicochemical and computational methods.
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Affiliation(s)
- Arthur Desvals
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | | | - Corentin Lefebvre
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Johann Rogier
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Clément Michelin
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, 63000 Clermont-Ferrand, France
| | - Samy Alioui
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Elodie Rousset
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Alfonso Pedone
- Università di Modena e Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Gilles Lemercier
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Norbert Hoffmann
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
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13
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Lemma AS, Brynildsen MP. Toxin Induction or Inhibition of Transcription or Translation Posttreatment Increases Persistence to Fluoroquinolones. mBio 2021; 12:e0198321. [PMID: 34399616 PMCID: PMC8406316 DOI: 10.1128/mbio.01983-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 07/19/2021] [Indexed: 02/03/2023] Open
Abstract
Toxin-antitoxin modules are widespread in prokaryotes, and the capacity of toxin accumulation to increase the tolerances of bacteria to antibiotics has been well documented. The conventional model for this functionality implies that an overabundance of toxin arrests bacterial growth, which inhibits processes targeted by antibiotics and thereby limits their corruption and the lethal damage that would ensue. Implicit in this model is that toxins exert their influence on antibiotic lethality before and/or during treatment, even though they are also present and functional after treatment concludes. Given recent evidence establishing that the period following antibiotic treatment (recovery) is important for the survival of nongrowing bacterial populations treated with fluoroquinolones (FQs), we assayed to what extent toxins influence bacterial survival during the recovery period. With both LdrD and MazF, toxins of type I and II systems, respectively, controlling accumulation to occur only after FQ treatment of nongrowing cultures resulted in significant increases in persisters. Further genetic investigation revealed important roles for homologous recombination and nucleotide excision repair machinery. Focusing on the wild type, we did not observe any SOS-induced toxin functioning in this manner; however, an analogous phenomenon was observed for wild-type Escherichia coli as well as uropathogenic E. coli (UPEC) when transcription or translation was inhibited during the post-FQ recovery period. Collectively, these data reveal the capacity of toxins to thwart FQ killing even after the treatment has concluded and show that FQ treatment of nongrowing bacteria can be rendered largely ineffective if bacteria cannot readily resume translation and growth at the conclusion of treatment. IMPORTANCE Overabundances of toxins have been shown to increase the antibiotic tolerances of bacteria. Largely, these effects have been attributed to the abilities of toxins to inhibit bacterial growth before and during antibiotic exposure. In this study, we assessed to what extent toxins can influence bacterial survival following antibiotic treatment, rather than before or during. Using two mechanistically distinct toxins, we show that their accumulations after antibiotic exposure have the capacity to increase the abundances of fluoroquinolone persisters from nongrowing populations. Further, we show with wild-type and uropathogenic E. coli that chemical inhibition of growth, not just that induced by toxins, produces analogous results. These observations reveal another dimension of how toxins influence antibiotic tolerance and highlight the importance of postantibiotic physiology on bacterial survival.
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Affiliation(s)
- Annabel S. Lemma
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
| | - Mark P. Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
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14
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Nag D, Dastidar DG, Chakrabarti G. Natural flavonoid morin showed anti-bacterial activity against Vibrio cholera after binding with cell division protein FtsA near ATP binding site. Biochim Biophys Acta Gen Subj 2021; 1865:129931. [PMID: 34023444 DOI: 10.1016/j.bbagen.2021.129931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 05/17/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Increasing antibiotic-resistance in bacterial strains has boosted the need to find new targets for drug delivery. FtsA, a major bacterial divisome protein can be a potent novel drug-target. METHODS AND RESULTS This study finds, morin (3,5,7,2',4'-pentahydroxyflavone), a bio-available flavonoid, had anti-bacterial activities against Vibrio cholerae, IC50 (50 μM) and MIC (150 μM). Morin (2 mM) kills ~20% of human lung fibroblast (WI38) and human intestinal epithelial (HIEC-6) cells in 24 h in-vitro. Fluorescence studies showed morin binds to VcFtsA (FtsA of V. cholerae) with a Kd of 4.68 ± 0.4 μM, inhibiting the protein's polymerization by 72 ± 7% at 25 μM concentration. Morin also affected VcFtsA's ATPase activity, recording ~80% reduction at 20 μM concentration. The in-silico binding study indicated binding sites of morin and ATP on VcFtsA had overlapping amino acids. Mant-ATP, a fluorescent ATP-derivative, showed increased fluorescence on binding to VcFtsA in absence of morin, but in its presence, Mant-ATP fluorescence decreased. VcFtsA-S40A mutant protein did not bind to morin. CONCLUSIONS VcFtsA-morin interaction inhibits the polymerization of the protein by affecting its ATPase activity. The destabilized VcFtsA assembly in-turn affected the cell division in V. cholerae, yielding an elongated morphology. GENERAL SIGNIFICANCE Collectively, these findings explore the anti-bacterial effect of morin on V. cholerae cells targeting VcFtsA, encouraging it to become a potent anti-bacterial agent. Low cytotoxicity of morin against human cells (host) is therapeutically advantageous. This study will also help in synthesizing novel derivatives that can target VcFtsA more efficiently.
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Affiliation(s)
- Debasish Nag
- Department of Biotechnology And Dr. B. C. Guha Centre for Genetic Engineering And Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, WB 700 019, India
| | - Debabrata Ghosh Dastidar
- Department of Biotechnology And Dr. B. C. Guha Centre for Genetic Engineering And Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, WB 700 019, India; Guru Nanak Institute of Pharmaceutical Science & Technology, 157/F Nilgunj Road, Panihati, Kolkata 700114, West Bengal, India
| | - Gopal Chakrabarti
- Department of Biotechnology And Dr. B. C. Guha Centre for Genetic Engineering And Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, WB 700 019, India.
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15
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Anandamide alters the membrane properties, halts the cell division and prevents drug efflux in multidrug resistant Staphylococcus aureus. Sci Rep 2021; 11:8690. [PMID: 33888802 PMCID: PMC8062478 DOI: 10.1038/s41598-021-88099-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/08/2021] [Indexed: 02/02/2023] Open
Abstract
Antibiotic resistance is a serious public health problem throughout the world. Overcoming methicillin and multidrug-resistant Staphylococcus aureus (MRSA/MDRSA) infections has become a challenge and there is an urgent need for new therapeutic approaches. We have previously demonstrated that the endocannabinoid Anandamide (AEA) can sensitize MRSA to antibiotics. Here we have studied the mechanism of action using a MDRSA clinical isolate that are sensitized by AEA to methicillin and norfloxacin. We found that AEA treatment halts the growth of both antibiotic-sensitive and antibiotic-resistant S. aureus. The AEA-treated bacteria become elongated and the membranes become ruffled with many protrusions. AEA treatment also leads to an increase in the percentage of bacteria having a complete septum, suggesting that the cell division is halted at this stage. The latter is supported by cell cycle analysis that shows an accumulation of bacteria in the G2/M phase after AEA treatment. We further observed that AEA causes a dose-dependent membrane depolarization that is partly relieved upon time. Nile red staining of the bacterial membranes indicates that AEA alters the membrane structures. Importantly, 4'-6-diamidino-2-phenylindole (DAPI) accumulation assay and ethidium bromide efflux (EtBr) assay unveiled that AEA leads to a dose-dependent drug accumulation by inhibiting drug efflux. In conclusion, our study demonstrates that AEA interferes with cell division, alters the membrane properties of MDRSA, and leads to increased intracellular drug retention, which can contribute to the sensitization of MDRSA to antibiotics.
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16
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Valente KP, Suleman A, Brolo AG. Exploring Diffusion and Cellular Uptake: Charged Gold Nanoparticles in an in Vitro Breast Cancer Model. ACS APPLIED BIO MATERIALS 2020; 3:6992-7002. [PMID: 35019358 DOI: 10.1021/acsabm.0c00872] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Gold nanoparticles have emerged as a prominent tool in nanomedicine, particularly for applications in cancer diagnostic and treatment. One of the challenges for the successful implementation of gold nanoparticles in cancer therapy is their delivery to the specific cancer area within the tumor microenvironment. The presence of cancer enables a poorly organized vascularization system, increasing the pressure with the microenvironment, limiting the uptake of particles. The physicochemical properties of the gold nanoparticles (size, shape, and surface charge) also have a significant effect on diffusion to the tumor site and cellular uptake. In this work, we analyzed the transport of 10 nm gold nanoparticles with different surface charges (neutral, negative, and positive) through a hydrogel composite. Three-dimensional in vitro models composed of breast cancer cells loaded in the hydrogel composite were used for the qualitative and quantitative evaluation of cellular uptake of the gold nanoparticles. Surprisingly, an inverse correlation between the diffusion coefficients of the nanoparticles and cellular uptake was demonstrated. Positively charged gold nanoparticles displayed high cellular uptake, although their diffusion coefficient indicated slow transport through the hydrogel matrix. Neutral particles, on the other hand, displayed fast diffusion but the lowest cellular uptake. The results obtained indicate that nanoparticle diffusion and cellular uptake should be studied together in realistic in vitro models for a true evaluation of transport in tumor microenvironments.
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Affiliation(s)
- Karolina P Valente
- Department of Mechanical Engineering, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada.,Centre for Advanced Materials and Related Technology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Afzal Suleman
- Department of Mechanical Engineering, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Alexandre G Brolo
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada.,Centre for Advanced Materials and Related Technology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
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17
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Zhao YM, Patange A, Sun DW, Tiwari B. Plasma-activated water: Physicochemical properties, microbial inactivation mechanisms, factors influencing antimicrobial effectiveness, and applications in the food industry. Compr Rev Food Sci Food Saf 2020; 19:3951-3979. [PMID: 33337045 DOI: 10.1111/1541-4337.12644] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/20/2020] [Accepted: 09/16/2020] [Indexed: 12/19/2022]
Abstract
Novel nonthermal inactivation technologies have been increasingly popular over the traditional thermal food processing methods due to their capacity in maintaining microbial safety and other quality parameters. Plasma-activated water (PAW) is a cutting-edge technology developed around a decade ago, and it has attracted considerable attention as a potential washing disinfectant. This review aims to offer an overview of the fundamentals and potential applications of PAW in the agri-food sector. A detailed description of the interactions between plasma and water can help to have a better understanding of PAW, hence the physicochemical properties of PAW are discussed. Further, this review elucidates the complex inactivation mechanisms of PAW, including oxidative stress and physical effect. In particular, the influencing factors on inactivation efficacy of PAW, including processing factors, characteristics of microorganisms, and background environment of water are extensively described. Finally, the potential applications of PAW in the food industry, such as surface decontamination for various food products, including fruits and vegetables, meat and seafood, and also the treatment on quality parameters are presented. Apart from decontamination, the applications of PAW for seed germination and plant growth, as well as meat curing are also summarized. In the end, the challenges and limitations of PAW for scale-up implementation, and future research efforts are also discussed. This review demonstrates that PAW has the potential to be successfully used in the food industry.
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Affiliation(s)
- Yi-Ming Zhao
- Food Refrigeration and Computerised Food Technology (FRCFT), School of Biosystems and Food Engineering, University College Dublin, National University of Ireland, Belfield, Dublin, Ireland.,Food Chemistry and Technology Department, Teagasc Food Research Centre Ashtown, Dublin, Ireland
| | - Apurva Patange
- Food Chemistry and Technology Department, Teagasc Food Research Centre Ashtown, Dublin, Ireland
| | - Da-Wen Sun
- Food Refrigeration and Computerised Food Technology (FRCFT), School of Biosystems and Food Engineering, University College Dublin, National University of Ireland, Belfield, Dublin, Ireland
| | - Brijesh Tiwari
- Food Chemistry and Technology Department, Teagasc Food Research Centre Ashtown, Dublin, Ireland
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18
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Navarro Chica CE, de Haan BJ, Faas MM, Smink AM, Sierra L, de Vos P, López BL. Design and characterization of Squalene-Gusperimus nanoparticles for modulation of innate immunity. Int J Pharm 2020; 590:119893. [PMID: 32956823 DOI: 10.1016/j.ijpharm.2020.119893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/12/2020] [Accepted: 09/14/2020] [Indexed: 01/18/2023]
Abstract
Immunosuppressive drugs are widely used for the treatment of autoimmune diseases and to prevent rejection in organ transplantation. Gusperimus is a relatively safe immunosuppressive drug with low cytotoxicity and reversible side effects. It is highly hydrophilic and unstable. Therefore, it requires administration in high doses which increases its side effects. To overcome this, here we encapsulated gusperimus as squalene-gusperimus nanoparticles (Sq-GusNPs). These nanoparticles (NPs) were obtained from nanoassembly of the squalene gusperimus (Sq-Gus) bioconjugate in water, which was synthesized starting from squalene. The size, charge, and dispersity of the Sq-GusNPs were optimized using the response surface methodology (RSM). The colloidal stability of the Sq-GusNPs was tested using an experimental block design at different storage temperatures after preparing them at different pH conditions. Sq-GusNPs showed to be colloidally stable, non-cytotoxic, readily taken up by cells, and with an anti-inflammatory effect sustained over time. We demonstrate that gusperimus was stabilized through its conjugation with squalene and subsequent formation of NPs allowing its controlled release. Overall, the Sq-GusNPs have the potential to be used as an alternative in approaches for the treatment of different pathologies where a controlled release of gusperimus could be required.
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Affiliation(s)
- Carlos E Navarro Chica
- Grupo de Investigación Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Antioquia, Colombia; Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9713 GZ Groningen, The Netherlands.
| | - Bart J de Haan
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9713 GZ Groningen, The Netherlands
| | - M M Faas
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9713 GZ Groningen, The Netherlands
| | - Alexandra M Smink
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9713 GZ Groningen, The Netherlands
| | - Ligia Sierra
- Grupo de Investigación Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Antioquia, Colombia
| | - Paul de Vos
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9713 GZ Groningen, The Netherlands
| | - Betty L López
- Grupo de Investigación Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Antioquia, Colombia
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19
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Schuster M, Steinberg G. The fungicide dodine primarily inhibits mitochondrial respiration in Ustilago maydis, but also affects plasma membrane integrity and endocytosis, which is not found in Zymoseptoria tritici. Fungal Genet Biol 2020; 142:103414. [PMID: 32474016 PMCID: PMC7526662 DOI: 10.1016/j.fgb.2020.103414] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 11/03/2022]
Abstract
Early reports in the fungus Ustilago maydis suggest that the amphipathic fungicide dodine disrupts the fungal plasma membrane (PM), thereby killing this corn smut pathogen. However, a recent study in the wheat pathogen Zymoseptoria tritici does not support such mode of action (MoA). Instead, dodine inhibits mitochondrial ATP-synthesis, both in Z. tritici and U. maydis. This casts doubt on an fungicidal activity of dodine at the PM. Here, we use a cell biological approach and investigate further the effect of dodine on the plasma membrane in both fungi. We show that dodine indeed breaks the integrity of the PM in U. maydis, indicated by a concentration-dependent cell depolarization. In addition, the fungicide reduces PM fluidity and arrests endocytosis by inhibiting the internalization of endocytic vesicles at the PM. This is likely due to impaired recruitment of the actin-crosslinker fimbrin to endocytic actin patches. However, quantitative data reveal that the effect on mitochondria represents the primary MoA in U. maydis. None of these plasma membrane-associated effects were found in dodine-treated Z. tritici cells. Thus, the physiological effect of an anti-fungal chemistry can differ between pathogens. This merits consideration when characterizing a given fungicide.
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Affiliation(s)
- Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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20
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Use of a Fluorescence-Based Assay To Measure Escherichia coli Membrane Potential Changes in High Throughput. Antimicrob Agents Chemother 2020; 64:AAC.00910-20. [PMID: 32631824 DOI: 10.1128/aac.00910-20] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 06/30/2020] [Indexed: 11/20/2022] Open
Abstract
Bacterial membrane potential is difficult to measure using classical electrophysiology techniques due to the small cell size and the presence of the peptidoglycan cell wall. Instead, chemical probes are often used to study membrane potential changes under conditions of interest. Many of these probes are fluorescent molecules that accumulate in a charge-dependent manner, and the resulting fluorescence change can be analyzed via flow cytometry or using a fluorescence microplate reader. Although this technique works well in many Gram-positive bacteria, it generates fairly low signal-to-noise ratios in Gram-negative bacteria due to dye exclusion by the outer membrane. We detail an optimized workflow that uses the membrane potential probe, 3,3'-diethyloxacarbocyanine iodide [DiOC2(3)], to measure Escherichia coli membrane potential changes in high throughput and describe the assay conditions that generate significant signal-to-noise ratios to detect membrane potential changes using a fluorescence microplate reader. A valinomycin calibration curve demonstrates this approach can robustly report membrane potentials over at least an ∼144-mV range with an accuracy of ∼12 mV. As a proof of concept, we used this approach to characterize the effects of some commercially available small molecules known to elicit membrane potential changes in other systems, increasing the repertoire of compounds known to perturb E. coli membrane energetics. One compound, the eukaryotic Ca2+ channel blocker amlodipine, was found to alter E. coli membrane potential and decrease the MIC of kanamycin, further supporting the value of this screening approach. This detailed methodology permits studying E. coli membrane potential changes quickly and reliably at the population level.
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21
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Li B, Yang N, Shan Y, Wang X, Hao Y, Mao R, Teng D, Fan H, Wang J. Therapeutic potential of a designed CSαβ peptide ID13 in Staphylococcus aureus-induced endometritis of mice. Appl Microbiol Biotechnol 2020; 104:6693-6705. [PMID: 32506158 PMCID: PMC7275135 DOI: 10.1007/s00253-020-10685-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/07/2020] [Accepted: 05/17/2020] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus is a common pathogen that can cause clinical and subclinical endometritis in humans and animals. In this study, a designed CSαβ peptide ID13 from DLP4 exhibited high stable antibacterial activity in simulated gastric fluid (90.79%), serum (99.54%), and different pH buffers (> 99%) against S. aureus CVCC 546 and lower cytotoxicity (89.62% viability) than its parent peptide DLP4 (74.14% viability) toward mouse endometrial epithelial cells (MEECs). ID13 caused a depolarization of bacterial membrane and downregulation of the expression of genes involved in membrane potential maintenance and biofilm formation. The in vitro efficacy analysis of ID13 showed a synergistic effect with vancomycin, ampicillin, rifampin, and ciprofloxacin; intracellular antimicrobial activity against S. aureus CVCC 546 in MEECs; and the ability to inhibit lipoteichoic acid-induced pro-inflammatory cytokines from RAW 264.7. In the S. aureus-induced endometritis of mice, similar to vancomycin, ID13 remarkably alleviated pathological conditions, inhibited the production of cytokines (TNF-α, IL-1ß, IL-6, and IL-10), and suppressed the TLR2-NF-κB signal pathway. Collectively, these results suggest that ID13 could be a potential candidate peptide for therapeutic application in S. aureus-induced endometritis. Key Points •Higher antibacterial activity and lower hemolysis of ID13 than DLP4. •ID13 could downregulate the genes of bacterial survival and infection. •ID13 could alleviate the S. aureus-induced endometritis of mice. •ID13 could regulate the cytokines and suppress the TLR2-NF-κB signal pathway.
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Affiliation(s)
- Bing Li
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Na Yang
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Yuxue Shan
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.,Tianjin Animal Science and Veterinary Research Institute, Tianjin, 300381, People's Republic of China
| | - Xiumin Wang
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Ya Hao
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China.,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Ruoyu Mao
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China. .,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
| | - Da Teng
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China. .,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
| | - Huan Fan
- Tianjin Animal Science and Veterinary Research Institute, Tianjin, 300381, People's Republic of China
| | - Jianhua Wang
- Team of Alternatives to Antibiotics, Gene Engineering Lab, Feed Research Institute, Chinese Academy of Agricultural Science, Beijing, 100081, People's Republic of China. .,Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
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22
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Boix-Lemonche G, Lekka M, Skerlavaj B. A Rapid Fluorescence-Based Microplate Assay to Investigate the Interaction of Membrane Active Antimicrobial Peptides with Whole Gram-Positive Bacteria. Antibiotics (Basel) 2020; 9:antibiotics9020092. [PMID: 32093104 PMCID: PMC7168298 DOI: 10.3390/antibiotics9020092] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 01/08/2023] Open
Abstract
Background: Membrane-active antimicrobial peptides (AMPs) are interesting candidates for the development of novel antimicrobials. Although their effects were extensively investigated in model membrane systems, interactions of AMPs with living microbial membranes are less known due to their complexity. The aim of the present study was to develop a rapid fluorescence-based microplate assay to analyze the membrane effects of AMPs in whole Staphylococcus aureus and Staphylococcus epidermidis. Methods: Bacteria were exposed to bactericidal and sub-inhibitory concentrations of two membrane-active AMPs in the presence of the potential-sensitive dye 3,3′-dipropylthiadicarbocyanine iodide (diSC3(5)) and the DNA staining dye propidium iodide (PI), to simultaneously monitor and possibly distinguish membrane depolarization and membrane permeabilization. Results: The ion channel-forming gramicidin D induced a rapid increase of diSC3(5), but not PI fluorescence, with slower kinetics at descending peptide concentrations, confirming killing due to membrane depolarization. The pore-forming melittin, at sub-MIC and bactericidal concentrations, caused, respectively, an increase of PI fluorescence in one or both dyes simultaneously, suggesting membrane permeabilization as a key event. Conclusions: This assay allowed the distinction between specific membrane effects, and it could be applied in the mode of action studies as well as in the screening of novel membrane-active AMPs.
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Affiliation(s)
- Gerard Boix-Lemonche
- Department of Medicine, University of Udine, Piazzale Kolbe, 4, 33100 Udine, Italy
- Correspondence: (G.B.-L.); (B.S.)
| | - Maria Lekka
- Polytechnic Department of Engineering and Architecture, University of Udine, Via delle Scienze 206, 33100 Udine, Italy
| | - Barbara Skerlavaj
- Department of Medicine, University of Udine, Piazzale Kolbe, 4, 33100 Udine, Italy
- Correspondence: (G.B.-L.); (B.S.)
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23
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Nikitushkin VD, Trenkamp S, Demina GR, Shleeva MO, Kaprelyants AS. Metabolic profiling of dormant Mycolicibacterium smegmatis cells' reactivation reveals a gradual assembly of metabolic processes. Metabolomics 2020; 16:24. [PMID: 32025943 DOI: 10.1007/s11306-020-1645-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/22/2020] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Under gradual acidification of the culture medium mycobacterial cells transit into a specific state characterized by low level of metabolic activity and morphological alterations. This state of non-replicative persistence (dormancy) is directly linked to physiological drug resistance, which complicates the efforts to eradicate the latent forms of TB. In order to find new anti-latent TB compounds, the metabolic processes which may occur in the state of dormancy and during the transition into the active state (reactivation) should be characterized. OBJECTIVES In the current study we analyzed the untargeted metabolomic profiles of dormant and reactivating Mycolicibacterium smegmatis cells (a model microorganism, bearing many common physiological traits of MTB), on the global scale level, since the characterization and analysis of the metabolites' dynamics would provide a comprehensive overview on global biochemical responses of the bacteria to stress conditions. METHODS The reactivation process was tracked by measuring the value of membrane potential, applying a ratio-metric approach, by the method of flow-cytometry. The crucial timepoints were selected and the bacteria were sampled to LC-MS metabolic profiling. RESULTS Reactivation of these cells after 60 days of storage revealed that this process proceeds in two stages: (I) a period, which lasts for 10 h and is characterized by a constant CFU number, unchangeable cell size, a minuscule increase of respiratory activity and a noticeable increase in membrane potential value, indicating the onset of the first metabolic processes during this time interval; the second phase (10-26 h) is characterized by acceleration of endogenous respiration, changes in the size of the cells and it finishes with the beginning of cells division. Analysis of the changes in the relative abundances of KEGG-annotated metabolites revealed that a significant number of metabolites, such as stearic acid, glycerol, D-glucose, trehalose-6-phosphate decrease their concentrations over the reactivation time, whereas in contrast, such metabolites as dodecanoic acid, mycobactin S, and other compounds of PG/AG biosynthesis are synthesized during reactivation. Differential analysis of metabolic profiles disclosed the activation of a number of metabolic pathways at the early reactivation stage: biosynthesis of secondary metabolites, purine and pyrimidine metabolism, glycerophospholipid and fatty acids metabolism etc. CONCLUSION: The data obtained indicate, despite the long-term storage of dormant cells in a state of minimal metabolic activity, according to metabolic profiling, they still retained a large number of metabolites. In the process of reactivation, the incremental stochastic assembly of the complete metabolic pathways occurs.
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Affiliation(s)
- Vadim D Nikitushkin
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071.
| | - Sandra Trenkamp
- Metabolomic Discoveries GmbH, Am Mühlenberg 11, 14476, Potsdam, Germany
| | - Galina R Demina
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
| | - Margarita O Shleeva
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
| | - Arseny S Kaprelyants
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
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Hall AE, Engevik MA, Oezguen N, Haag A, Versalovic J. ClC transporter activity modulates histidine catabolism in Lactobacillus reuteri by altering intracellular pH and membrane potential. Microb Cell Fact 2019; 18:212. [PMID: 31830990 PMCID: PMC6909576 DOI: 10.1186/s12934-019-1264-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/02/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Histamine is a key mediator of the anti-inflammatory activity conferred by the probiotic organism Lactobacillus reuteri ATCC PTA 6475 in animal models of colitis and colorectal cancer. In L. reuteri, histamine synthesis and secretion requires L-histidine decarboxylase and a L-histidine/histamine exchanger. Chloride channel (ClC)-family proton/chloride antiporters have been proposed to act as electrochemical shunts in conjunction with amino acid decarboxylase systems, correcting ion imbalances generated by decarboxylation through fixed ratio exchange of two chloride ions for one proton. This family is unique among transporters by facilitating ion flux in either direction. Here we examine the histidine decarboxylase system in relation to ClC antiporters in the probiotic organism Lactobacillus reuteri. RESULTS In silico analyses reveal that L. reuteri possesses two ClC transporters, EriC and EriC2, as well as a complete histidine decarboxylase gene cluster (HDC) for the synthesis and export of histamine. When the transport activity of either proton/chloride antiporter is disrupted by genetic manipulation, bacterial histamine output is reduced. Using fluorescent reporter assays, we further show that ClC transporters affect histamine output by altering intracellular pH and membrane potential. ClC transport also alters the expression and activity of two key HDC genes: the histidine decarboxylase (hdcA) and the histidine/histamine exchanger (hdcP). CONCLUSIONS Histamine production is a potentially beneficial feature for intestinal microbes by promoting long-term colonization and suppression of inflammation and host immune responses. ClC transporters may serve as tunable modulators for histamine production by L. reuteri and other gut microbes.
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Affiliation(s)
- Anne E Hall
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology, Texas Children's Hospital, Houston, TX, 77030, USA
- Infectious Disease Laboratories, Akron Children's Hospital, Akron, OH, 44308, USA
| | - Melinda A Engevik
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology, Texas Children's Hospital, Houston, TX, 77030, USA
| | - Numan Oezguen
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology, Texas Children's Hospital, Houston, TX, 77030, USA
| | - Anthony Haag
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology, Texas Children's Hospital, Houston, TX, 77030, USA
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Pathology, Texas Children's Hospital, Houston, TX, 77030, USA.
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Liu H, Li Z, Cao Y, Cui Y, Yang X, Meng Z, Wang R. Effect of chondrocyte mitochondrial dysfunction on cartilage degeneration: A possible pathway for osteoarthritis pathology at the subcellular level. Mol Med Rep 2019; 20:3308-3316. [PMID: 31432161 PMCID: PMC6755144 DOI: 10.3892/mmr.2019.10559] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 04/04/2019] [Indexed: 11/28/2022] Open
Abstract
Previous studies identified that chondrocyte apoptosis serves an important role in osteoarthritis (OA). However, the mechanisms of cartilage degeneration induced by apoptosis remain unclear. The present study investigated the role of mitochondrial dysfunction in OA pathology. A total of 30 cartilage samples presenting an Outerbridge score ranging between 0 and III were collected during total knee arthroplasty. Half of the samples were embedded for observation by transmission electron microscopy. The remaining samples were digested, and chondrocytes were isolated from normal and OA tissues. Subsequently, the enzymatic activity of factors of the mitochondrial respiratory chain (MRC), and mitochondrial membrane potential (Δψm), were quantified. Furthermore, chondrocytes were treated with rotenone (Ro), a specific inhibitor of the MRC, and curcumin (Cur), a mitochondrial protective agent, with the aim of analyzing the relationship between mitochondrial dysfunction and chondrocyte apoptosis. The mitochondria of OA chondrocytes showed apoptosis-associated morphological alterations compared with normal cells. The Δψm and the activity of MRC enzymes were decreased in OA chondrocytes. Moreover, compared with normal chondrocytes, treatment with Ro was able to induce morphological changes reminiscent of the phenotype observed in OA chondrocytes. Additionally, Ro inhibited cellular proliferation, increased the apoptotic rate, and decreased the Δψm and the secretion of type II collagen. Furthermore, Cur could partly reverse the effects caused by treatment with Ro. The present data suggested that mitochondrial function was impaired in OA chondrocytes, resulting in an increased chondrocyte apoptosis and decreased type II collagen secretion. In addition, treatment with Cur protected the mitochondrial function and prevented cartilage degeneration. Collectively, the present results suggested that mitochondrial dysfunction may aggravate cartilage degeneration in the pathogenesis of OA.
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Affiliation(s)
- Heng Liu
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Zhuoyang Li
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Yongping Cao
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Yunpeng Cui
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Xin Yang
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Zhichao Meng
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
| | - Rui Wang
- Department of Orthopedics, Peking University First Hospital, Beijing 100034, P.R. China
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Smitten KL, Southam HM, de la Serna JB, Gill MR, Jarman PJ, Smythe CGW, Poole RK, Thomas JA. Using Nanoscopy To Probe the Biological Activity of Antimicrobial Leads That Display Potent Activity against Pathogenic, Multidrug Resistant, Gram-Negative Bacteria. ACS NANO 2019; 13:5133-5146. [PMID: 30964642 DOI: 10.1021/acsnano.8b08440] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Medicinal leads that are also compatible with imaging technologies are attractive, as they facilitate the development of therapeutics through direct mechanistic observations at the molecular level. In this context, the uptake and antimicrobial activities of several luminescent dinuclear RuII complexes against E. coli were assessed and compared to results obtained for another ESKAPE pathogen, the Gram-positive major opportunistic pathogen Enterococcus faecalis, V583. The most promising lead displays potent activity, particularly against the Gram-negative bacteria, and potency is retained in the uropathogenic multidrug resistant EC958 ST131 strain. Exploiting the inherent luminescent properties of this complex, super-resolution STED nanoscopy was used to image its initial localization at/in cellular membranes and its subsequent transfer to the cell poles. Membrane damage assays confirm that the complex disrupts the bacterial membrane structure before internalization. Mammalian cell culture and animal model studies indicate that the complex is not toxic to eukaryotes, even at concentrations that are several orders of magnitude higher than its minimum inhibitory concentration (MIC). Taken together, these results have identified a lead molecular architecture for hard-to-treat, multiresistant, Gram-negative bacteria, which displays activities that are already comparable to optimized natural product-based leads.
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Affiliation(s)
- Kirsty L Smitten
- Department of Chemistry , The University of Sheffield , Western Bank , Sheffield S3 7HF , U.K
| | - Hannah M Southam
- Department of Molecular Biology and Biotechnology , The University of Sheffield , Western Bank , Sheffield S10 2TN , U.K
| | - Jorge Bernardino de la Serna
- Central Laser Facility, Rutherford Appleton Laboratory, Research Complex at Harwell , Science and Technology Facilities Council , Harwell-Oxford , Didcot OX11 0QX , U.K
- Department of Physics , King's College London , London WC2R 2LS , U.K
| | - Martin R Gill
- Department of Chemistry , The University of Sheffield , Western Bank , Sheffield S3 7HF , U.K
| | - Paul J Jarman
- Department of Biomedical Science , The University of Sheffield , Western Bank , Sheffield S10 2TN , U.K
| | - Carl G W Smythe
- Department of Biomedical Science , The University of Sheffield , Western Bank , Sheffield S10 2TN , U.K
| | - Robert K Poole
- Department of Molecular Biology and Biotechnology , The University of Sheffield , Western Bank , Sheffield S10 2TN , U.K
| | - Jim A Thomas
- Department of Chemistry , The University of Sheffield , Western Bank , Sheffield S3 7HF , U.K
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Very rapid flow cytometric assessment of antimicrobial susceptibility during the apparent lag phase of microbial (re)growth. Microbiology (Reading) 2019; 165:439-454. [DOI: 10.1099/mic.0.000777] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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van Hensbergen VP, Movert E, de Maat V, Lüchtenborg C, Le Breton Y, Lambeau G, Payré C, Henningham A, Nizet V, van Strijp JAG, Brügger B, Carlsson F, McIver KS, van Sorge NM. Streptococcal Lancefield polysaccharides are critical cell wall determinants for human Group IIA secreted phospholipase A2 to exert its bactericidal effects. PLoS Pathog 2018; 14:e1007348. [PMID: 30321240 PMCID: PMC6201954 DOI: 10.1371/journal.ppat.1007348] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 10/25/2018] [Accepted: 09/20/2018] [Indexed: 12/21/2022] Open
Abstract
Human Group IIA secreted phospholipase A2 (hGIIA) is an acute phase protein with bactericidal activity against Gram-positive bacteria. Infection models in hGIIA transgenic mice have suggested the importance of hGIIA as an innate defense mechanism against the human pathogens Group A Streptococcus (GAS) and Group B Streptococcus (GBS). Compared to other Gram-positive bacteria, GAS is remarkably resistant to hGIIA activity. To identify GAS resistance mechanisms, we exposed a highly saturated GAS M1 transposon library to recombinant hGIIA and compared relative mutant abundance with library input through transposon-sequencing (Tn-seq). Based on transposon prevalence in the output library, we identified nine genes, including dltA and lytR, conferring increased hGIIA susceptibility. In addition, seven genes conferred increased hGIIA resistance, which included two genes, gacH and gacI that are located within the Group A Carbohydrate (GAC) gene cluster. Using GAS 5448 wild-type and the isogenic gacI mutant and gacI-complemented strains, we demonstrate that loss of the GAC N-acetylglucosamine (GlcNAc) side chain in the ΔgacI mutant increases hGIIA resistance approximately 10-fold, a phenotype that is conserved across different GAS serotypes. Increased resistance is associated with delayed penetration of hGIIA through the cell wall. Correspondingly, loss of the Lancefield Group B Carbohydrate (GBC) rendered GBS significantly more resistant to hGIIA-mediated killing. This suggests that the streptococcal Lancefield antigens, which are critical determinants for streptococcal physiology and virulence, are required for the bactericidal enzyme hGIIA to exert its bactericidal function.
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Affiliation(s)
- Vincent P. van Hensbergen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Elin Movert
- Department of Experimental Medical Science, Section for Immunology, Lund University, Lund, Sweden
| | - Vincent de Maat
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | - Yoann Le Breton
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States of America
| | - Gérard Lambeau
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Department of Biochemistry, Valbonne, France
| | - Christine Payré
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Department of Biochemistry, Valbonne, France
| | - Anna Henningham
- Department of Pediatrics and Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Jos A. G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Britta Brügger
- Heidelberg University, Biochemistry Center (BZH), Heidelberg, Germany
| | - Fredric Carlsson
- Department of Experimental Medical Science, Section for Immunology, Lund University, Lund, Sweden
- Department of Biology, Section for Molecular Cell Biology, Lund University, Lund, Sweden
| | - Kevin S. McIver
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States of America
| | - Nina M. van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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Abstract
Bacterial populations harbor a small fraction of cells that display transient multidrug tolerance. These so-called persister cells are extremely difficult to eradicate and contribute to the recalcitrance of chronic infections. Several signaling pathways leading to persistence have been identified. However, it is poorly understood how the effectors of these pathways function at the molecular level. In a previous study, we reported that the conserved GTPase Obg induces persistence in Escherichia coli via transcriptional upregulation of the toxin HokB. In the present study, we demonstrate that HokB inserts in the cytoplasmic membrane where it forms pores. The pore-forming capacity of the HokB peptide is demonstrated by in vitro conductance measurements on synthetic and natural lipid bilayers, revealing an asymmetrical conductance profile. Pore formation is directly linked to persistence and results in leakage of intracellular ATP. HokB-induced persistence is strongly impeded in the presence of a channel blocker, thereby providing a direct link between pore functioning and persistence. Furthermore, the activity of HokB pores is sensitive to the membrane potential. This sensitivity presumably results from the formation of either intermediate or mature pore types depending on the membrane potential. Taken together, these results provide a detailed view on the mechanistic basis of persister formation through the effector HokB.IMPORTANCE There is increasing awareness of the clinical importance of persistence. Indeed, persistence is linked to the recalcitrance of chronic infections, and evidence is accumulating that persister cells constitute a pool of viable cells from which resistant mutants can emerge. Unfortunately, persistence is a poorly understood process at the mechanistic level. In this study, we unraveled the pore-forming activity of HokB in E. coli and discovered that these pores lead to leakage of intracellular ATP, which is correlated with the induction of persistence. Moreover, we established a link between persistence and pore activity, as the number of HokB-induced persister cells was strongly reduced using a channel blocker. The latter opens opportunities to reduce the number of persister cells in a clinical setting.
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30
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Patakova P, Kolek J, Sedlar K, Koscova P, Branska B, Kupkova K, Paulova L, Provaznik I. Comparative analysis of high butanol tolerance and production in clostridia. Biotechnol Adv 2018; 36:721-738. [DOI: 10.1016/j.biotechadv.2017.12.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 12/24/2022]
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Abstract
Mitochondria are key organelles implicated in energy supply and apoptosis. Therefore, tracking mitochondria and measuring their membrane potential is of crucial interest to monitor the CD95-mediated apoptotic signal. In this chapter, we report how we evaluate the drop of the mitochondrial transmembrane potential in leukemic cells and adherent triple negative breast cancer cells exposed to cytotoxic CD95L. We describe a simple, robust, and well-established protocol using classical fluorescent probes, DIOC6(3) and TMRM. Living cells are loaded with these cationic dyes, which accumulate in mitochondria. After CD95 activation, organelle depolarization is assessed using flow cytometry.
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32
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Sianglum W, Saeloh D, Tongtawe P, Wootipoom N, Indrawattana N, Voravuthikunchai SP. Early Effects of Rhodomyrtone on Membrane Integrity in Methicillin-Resistant Staphylococcus aureus. Microb Drug Resist 2017; 24:882-889. [PMID: 29215320 DOI: 10.1089/mdr.2016.0294] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Strong evidence of high potency of rhodomyrtone as a promising antibacterial agent against pathogenic gram-positive bacteria has been clearly demonstrated in our previous work. The aim of this study was to provide insight into early action of rhodomyrtone, an acylphloroglucinol, on membrane damage in multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA). Early effects of rhodomyrtone on the bacterial membrane integrity were detected in a time-course study. Flow cytometry revealed a reduction in green fluorescent emission and increase in uptake of propidium iodide in rhodomyrtone-treated bacterial cells in a concentration- and time-dependent manner. Disruption of cytoplasmic membrane was further monitored by measuring cellular adenosine triphosphate (ATP) and potassium ion (K+). Leakage of both ATP and K+ and significant decrease in intracellular ATP in MRSA were observed following treatment. Pronounced changes in the bacterial ultrastructure and morphology were confirmed by transmission electron microscopy and scanning electron microscopy. Bacterial cell disruption, holes in cell surface, and bulge formations were noted in rhodomyrtone-treated cells. In this study, we provided relevant data to clarify that rhodomyrtone is a bacterial cell membrane-damaging agent. A possible early effect of this novel compound involves bacterial membrane disruption.
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Affiliation(s)
- Wipawadee Sianglum
- 1 Department of Microbiology and Excellence Research Laboratory on Natural Products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University , Hat Yai, Thailand
| | - Dennapa Saeloh
- 2 Faculty of Medical Technology, Prince of Songkla University , Hat Yai, Thailand
| | - Pongsri Tongtawe
- 3 Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University , Pathumtanee, Thailand
| | - Natthakul Wootipoom
- 4 Immunology and Virology Unit, Department of Pathology, Faculty of Medicine, Prince of Songkla University , Hat Yai, Thailand
| | - Nitaya Indrawattana
- 5 Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University , Bangkok, Thailand
| | - Supayang Piyawan Voravuthikunchai
- 1 Department of Microbiology and Excellence Research Laboratory on Natural Products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University , Hat Yai, Thailand
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Groundwater PW, Narlawar R, Liao VWY, Bhattacharya A, Srivastava S, Kunal K, Doddareddy M, Oza PM, Mamidi R, Marrs ECL, Perry JD, Hibbs DE, Panda D. A Carbocyclic Curcumin Inhibits Proliferation of Gram-Positive Bacteria by Targeting FtsZ. Biochemistry 2017; 56:514-524. [DOI: 10.1021/acs.biochem.6b00879] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Paul W. Groundwater
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Rajeshwar Narlawar
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Vivian Wan Yu Liao
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Anusri Bhattacharya
- Department
of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Shalini Srivastava
- Department
of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Kishore Kunal
- Department
of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Munikumar Doddareddy
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Pratik M. Oza
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Ramesh Mamidi
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Emma C. L. Marrs
- Microbiology
Department, Freeman Hospital, High Heaton, Newcastle upon Tyne NE7 7DN, United Kingdom
| | - John D. Perry
- Microbiology
Department, Freeman Hospital, High Heaton, Newcastle upon Tyne NE7 7DN, United Kingdom
| | - David E. Hibbs
- Faculty
of Pharmacy, The University of Sydney, Pharmacy and Bank Building, Science
Road, Sydney, NSW 2006, Australia
| | - Dulal Panda
- Department
of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
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Shuona C, Hua Y, Jingjing C, Hui P, Zhi D. Physiology and bioprocess of single cell of Stenotrophomonas maltophilia in bioremediation of co-existed benzo[a]pyrene and copper. JOURNAL OF HAZARDOUS MATERIALS 2017; 321:9-17. [PMID: 27607928 DOI: 10.1016/j.jhazmat.2016.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/19/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are generally present in mixtures in the e-waste dismantling areas, posing serious health risk to the local people. Bioremediation has been considered as a promising approach for PAHs and heavy metals removal. In this study, we applied flow cytometry to obtain a better understanding of membrane potential (MP), apoptosis and cell cycle of Stenotrophomonas maltophilia affected by combined pollutants of benzo[a]pyrene(BaP) and Cu(II). The results showed that BaP was the main factor damaging the cell membrane and influencing the MP. S. maltophilia could even protect against upsetting situation by encouraging early apoptosis, whereby compromised cells committed suicide, as a result, which, in turn, facilitated the metabolism of the bacteria with high-vitality. Furthermore, even if the bacterial cell division was blocked and stopped reproduction, a large number of key enzymes inside cells could still be used for degradation of BaP. The expression of protein related to the transport and metabolism of BaP, regulation of redox reactions and phosphorylation in bacterial cell during bioprocess were evident different.
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Affiliation(s)
- Chen Shuona
- College of Natural Resources and Environment of South China Agricultural University, Guangzhou 510642, China
| | - Yin Hua
- Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education; School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
| | - Chang Jingjing
- College of Natural Resources and Environment of South China Agricultural University, Guangzhou 510642, China
| | - Peng Hui
- Department of Chemistry, School of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Dang Zhi
- Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education; School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
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Aebisher D, Bartusik D, Tabarkiewicz J. Laser flow cytometry as a tool for the advancement of clinical medicine. Biomed Pharmacother 2017; 85:434-443. [DOI: 10.1016/j.biopha.2016.11.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/08/2016] [Accepted: 11/08/2016] [Indexed: 12/11/2022] Open
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Friehs E, AlSalka Y, Jonczyk R, Lavrentieva A, Jochums A, Walter JG, Stahl F, Scheper T, Bahnemann D. Toxicity, phototoxicity and biocidal activity of nanoparticles employed in photocatalysis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2016. [DOI: 10.1016/j.jphotochemrev.2016.09.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Andreyeva AY, Soldatov AA, Mukhanov VS. The influence of acute hypoxia on the functional and morphological state of the black scorpionfish red blood cells. In Vitro Cell Dev Biol Anim 2016; 53:312-319. [PMID: 27834044 DOI: 10.1007/s11626-016-0111-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/21/2016] [Indexed: 10/24/2022]
Abstract
The investigation of the mechanisms of red blood cell steadiness to the oxygen lack in tolerant teleosts is of current scientific interest. Black scorpionfish, Scorpaena porcus L., is a widespread benthal species in the Black Sea and is highly resistant to hypoxic influence. The morphological state of black scorpionfish red blood cells under acute hypoxia was assessed using DNA-binding dye SYBR Green I and fluorescent microscopy. Changes in membrane potential of mitochondria and functional activity of cells were determined by rhodamine 123 (R123) and fluorescein diacetate (FDA) fluorescence. Oxygen deficiency leads to bidirectional changes in volume of erythrocytes and their nuclei. Between 0.57 and 1.76 mg О2 l-1, both parameters increased on 3-12 and 7-21%, respectively. At 1.76-4.03, cells shrank on 1.5-6.0% and nucleus size decreased on 1.5-3%. Acute hypoxia induced a significant increase of R123 (12-60%) and FDA (30-184%) fluorescence. These reactions are caused by a probable decrease in erythrocyte membrane permeability.
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Affiliation(s)
- Aleksandra Y Andreyeva
- Department of Animal Physiology and Biochemistry, Institute of Marine Biological Research, Russian Academy of Sciences, Leninsky Ave, 14, Moscow, Russia, 119991.
| | - Aleksander A Soldatov
- Department of Animal Physiology and Biochemistry, Institute of Marine Biological Research, Russian Academy of Sciences, Leninsky Ave, 14, Moscow, Russia, 119991
| | - Vladimir S Mukhanov
- Department of Plankton, Institute of Marine Biological Research, Russian Academy of Sciences, Moscow, Russia
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38
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Fan XY, Chen XY, Liu YJ, Zhong HM, Jiang FL, Liu Y. Oxidative stress-mediated intrinsic apoptosis in human promyelocytic leukemia HL-60 cells induced by organic arsenicals. Sci Rep 2016; 6:29865. [PMID: 27432798 PMCID: PMC4949440 DOI: 10.1038/srep29865] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/27/2016] [Indexed: 01/09/2023] Open
Abstract
Arsenic trioxide has shown the excellent therapeutic efficiency for acute promyelocytic leukemia. Nowadays, more and more research focuses on the design of the arsenic drugs, especially organic arsenicals, and on the mechanism of the inducing cell death. Here we have synthesized some organic arsenicals with Schiff base structure, which showed a better antitumor activity for three different kinds of cancer cell lines, namely HL-60, SGC 7901 and MCF-7. Compound 2a (2-(((4-(oxoarsanyl)phenyl)imino)methyl)phenol) and 2b (2-methoxy-4-(((4-(oxoarsanyl)phenyl)imino)methyl)phenol) were chosen for further mechanism study due to their best inhibitory activities for HL-60 cells, of which the half inhibitory concentration (IC50) were 0.77 μM and 0.51 μM, respectively. It was illustrated that 2a or 2b primarily induced the elevation of reactive oxygen species, decrease of glutathione level, collapse of mitochondrial membrane potential, release of cytochrome c, activation of Caspase-3 and apoptosis, whereas all of the phenomena can be eliminated by the addition of antioxidants. Therefore, we concluded that compound 2a and 2b can induce the oxidative stress-mediated intrinsic apoptosis in HL-60 cells. Both the simplicity of structure with Schiff base group and the better anticancer efficiency demonstrate that organic arsenicals are worthy of further exploration as a class of potent antitumor drugs.
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Affiliation(s)
- Xiao-Yang Fan
- State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Xin-You Chen
- School of Chemistry and Materials Science, Hubei Engineering University, Xiaogan 432000, P. R. China
| | - Yu-Jiao Liu
- State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Hui-Min Zhong
- State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Feng-Lei Jiang
- State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yi Liu
- State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.,School of Chemistry and Materials Science, Hubei Engineering University, Xiaogan 432000, P. R. China
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Boda SK, Basu B. Engineered biomaterial and biophysical stimulation as combinatorial strategies to address prosthetic infection by pathogenic bacteria. J Biomed Mater Res B Appl Biomater 2016; 105:2174-2190. [PMID: 27404048 DOI: 10.1002/jbm.b.33740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/08/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022]
Abstract
A plethora of antimicrobial strategies are being developed to address prosthetic infection. The currently available methods for implant infection treatment include the use of antibiotics and revision surgery. Among the bacterial strains, Staphylococcus species pose significant challenges particularly, with regard to hospital acquired infections. In order to combat such life threatening infectious diseases, researchers have developed implantable biomaterials incorporating nanoparticles, antimicrobial reinforcements, surface coatings, slippery/non-adhesive and contact killing surfaces. This review discusses a few of the biomaterial and biophysical antimicrobial strategies, which are in the developmental stage and actively being pursued by several research groups. The clinical efficacy of biophysical stimulation methods such as ultrasound, electric and magnetic field treatments against prosthetic infection depends critically on the stimulation protocol and parameters of the treatment modality. A common thread among the three biophysical stimulation methods is the mechanism of bactericidal action, which is centered on biophysical rupture of bacterial membranes, the generation of reactive oxygen species (ROS) and bacterial membrane depolarization evoked by the interference of essential ion-transport. Although the extent of antimicrobial effect, normally achieved through biophysical stimulation protocol is insufficient to warrant therapeutic application, a combination of antibiotic/ROS inducing agents and biophysical stimulation methods can elicit a clinically relevant reduction in viable bacterial numbers. In this review, we present a detailed account of both the biomaterial and biophysical approaches for achieving maximum bacterial inactivation. Summarizing, the biophysical stimulation methods in a combinatorial manner with material based strategies can be a more potent solution to control bacterial infections. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2174-2190, 2017.
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Affiliation(s)
- Sunil Kumar Boda
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Bikramjit Basu
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, 560012, India
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40
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Keane J, Tajouri L, Gray B. Recombinant human growth hormone and insulin-like growth factor-1 do not affect mitochondrial derived highly reactive oxygen species production in peripheral blood mononuclear cells under conditions of substrate saturation in-vitro. Nutr Metab (Lond) 2016; 13:45. [PMID: 27382409 PMCID: PMC4932701 DOI: 10.1186/s12986-016-0105-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/30/2016] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The purpose of this study was to investigate the mitochondrial effects exerted by physiological and supra-physiological concentrations of recombinant human growth hormone (rhGH) and recombinant insulin-like growth factor-1 (rIGF-1) under conditions of substrate saturation in peripheral blood mononuclear cells (PBMCs). METHODS PBMCs from healthy male subjects were treated with either rhGH, at concentrations of 0.5, 5 and 50 μg/L, or rIGF-1 at concentrations of 100, 300 and 500 μg/L for 4 h. Mitochondrial membrane potential (Δψm) and mitochondrial levels of highly reactive oxygen species (hROS) were subsequently analysed. This analysis was performed by flow cytometry in digitonin permeabilized cells, following treatment with saturating concentrations of various respiratory substrate combinations and the use of specific electron transport chain (ETC.) complex inhibitors, enabling control over both the sites of electron entry into the ETC. at complexes I and II and the entry of electrons from reduced carriers involved in β-oxidation at the level of ubiquinol. RESULTS Neither rhGH nor rIGF-1 exerted any significant effect on Δψm or the rate of hROS production in either lymphocyte or monocyte sub-populations under any of the respiratory conditions analysed. CONCLUSION That neither hormone was capable of attenuating levels of oxidative stress mediated via either complex I linked respiration or lipid-derived respiration could have serious health implications for the use of rhGH in healthy individuals, which is frequently associated with significant increases in the bioavailability of free fatty acids (FFA). Such elevated supplies of lipid-derived substrates to the mitochondria could lead to oxidative damage which would negatively impact mitochondrial function.
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Affiliation(s)
- James Keane
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland Australia
| | - Lotti Tajouri
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland Australia
| | - Bon Gray
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland Australia
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41
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Monitoring the live to dead transition of bacteria during thermal stress by a multi-method approach. J Microbiol Methods 2016; 123:24-30. [DOI: 10.1016/j.mimet.2016.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 11/21/2022]
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42
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Premkumar KV, Chaube SK. Increased level of reactive oxygen species persuades postovulatory aging-mediated spontaneous egg activation in rat eggs cultured in vitro. In Vitro Cell Dev Biol Anim 2016; 52:576-88. [PMID: 26896066 DOI: 10.1007/s11626-016-0007-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/25/2016] [Indexed: 11/29/2022]
Abstract
The present study was aimed to find out whether increased level of reactive oxygen species (ROS) particularity hydrogen peroxide (H2O2) could persuade postovulatory aging-mediated abortive spontaneous egg activation (SEA) in rat eggs cultured in vitro. For this purpose, ROS and H2O2 levels, mitochondria distribution and its membrane potential, p286-CaMK-II, Emi2, Thr-161 phophorylated cyclin-dependent protein kinase1 (Cdk1) as well as cyclin B1 levels, in vitro effects of 3-tert-butyl-4 hydroxy anisole (BHA), pentoxifylline and dibutyryl-adenosine 3',5'-cyclic monophosphate (db-cAMP) were analyzed during postovulatory aging-induced abortive SEA in vitro. Data of the present study suggest that postovulatory aging increased H2O2 levels, disturbed mitochondrial distribution pattern and mitochondrial membrane potential (MMP) in eggs. There was an significant increase of p286-CaMK-II level, while Emi2 level reduced significantly during egg aging in vitro. The reduced Emi2 level was associated with decreased Thr-161 phosphorylated cyclin-dependent kinase-1 (Cdk1) as well as cyclin B1 level in aged eggs that underwent abortive SEA. Further, supplementation of pentoxifylline, db-cAMP, and BHA protected postovulatory aging-mediated abortive SEA in concentration-dependent manner. These data suggest that postovulatory aging increased H2O2 levels, reduced MMP, and increased p286-CaMK-II. The increased p286-CaMK-II was associated with reduced Emi2 level and maturation-promoting factor levels during postovulatory aging-mediated abortive SEA. Drugs that elevate cAMP directly or indirectly and BHA protected postovulatory aging-mediated abortive SEA possibly by reducing ROS level in rat eggs cultured in vitro.
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Affiliation(s)
- Karuppanan V Premkumar
- Cell Physiology Laboratory, Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi, 221005, UP, India
| | - Shail K Chaube
- Cell Physiology Laboratory, Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi, 221005, UP, India.
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43
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Mok WWK, Park JO, Rabinowitz JD, Brynildsen MP. RNA Futile Cycling in Model Persisters Derived from MazF Accumulation. mBio 2015; 6:e01588-15. [PMID: 26578677 PMCID: PMC4659464 DOI: 10.1128/mbio.01588-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 10/19/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Metabolism plays an important role in the persister phenotype, as evidenced by the number of strategies that perturb metabolism to sabotage this troublesome subpopulation. However, the absence of techniques to isolate high-purity populations of native persisters has precluded direct measurement of persister metabolism. To address this technical challenge, we studied Escherichia coli populations whose growth had been inhibited by the accumulation of the MazF toxin, which catalyzes RNA cleavage, as a model system for persistence. Using chromosomally integrated, orthogonally inducible promoters to express MazF and its antitoxin MazE, bacterial populations that were almost entirely tolerant to fluoroquinolone and β-lactam antibiotics were obtained upon MazF accumulation, and these were subjected to direct metabolic measurements. While MazF model persisters were nonreplicative, they maintained substantial oxygen and glucose consumption. Metabolomic analysis revealed accumulation of all four ribonucleotide monophosphates (NMPs). These results are consistent with a MazF-catalyzed RNA futile cycle, where the energy derived from catabolism is dissipated through continuous transcription and MazF-mediated RNA degradation. When transcription was inhibited, oxygen consumption and glucose uptake decreased, and nucleotide triphosphates (NTPs) and NTP/NMP ratios increased. Interestingly, the MazF-inhibited cells were sensitive to aminoglycosides, and this sensitivity was blocked by inhibition of transcription. Thus, in MazF model persisters, futile cycles of RNA synthesis and degradation result in both significant metabolic demands and aminoglycoside sensitivity. IMPORTANCE Metabolism plays a critical role in controlling each stage of bacterial persistence (shutdown, stasis, and reawakening). In this work, we generated an E. coli strain in which the MazE antitoxin and MazF toxin were artificially and independently inducible, and we used this strain to generate model persisters and study their metabolism. We found that even though growth of the model persisters was inhibited, they remained highly metabolically active. We further uncovered a futile cycle driven by continued transcription and MazF-mediated transcript degradation that dissipated the energy derived from carbon catabolism. Interestingly, the existence of this futile cycle acted as an Achilles' heel for MazF model persisters, rendering them vulnerable to killing by aminoglycosides.
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Affiliation(s)
- Wendy W K Mok
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
| | - Junyoung O Park
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA Department of Chemistry, Princeton University, Princeton, New Jersey, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
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44
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Langemann T, Mayr UB, Meitz A, Lubitz W, Herwig C. Multi-parameter flow cytometry as a process analytical technology (PAT) approach for the assessment of bacterial ghost production. Appl Microbiol Biotechnol 2015; 100:409-18. [PMID: 26521248 DOI: 10.1007/s00253-015-7089-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/29/2015] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
Abstract
Flow cytometry (FCM) is a tool for the analysis of single-cell properties in a cell suspension. In this contribution, we present an improved FCM method for the assessment of E-lysis in Enterobacteriaceae. The result of the E-lysis process is empty bacterial envelopes-called bacterial ghosts (BGs)-that constitute potential products in the pharmaceutical field. BGs have reduced light scattering properties when compared with intact cells. In combination with viability information obtained from staining samples with the membrane potential-sensitive fluorescent dye bis-(1,3-dibutylarbituric acid) trimethine oxonol (DiBAC4(3)), the presented method allows to differentiate between populations of viable cells, dead cells, and BGs. Using a second fluorescent dye RH414 as a membrane marker, non-cellular background was excluded from the data which greatly improved the quality of the results. Using true volumetric absolute counting, the FCM data correlated well with cell count data obtained from colony-forming units (CFU) for viable populations. Applicability of the method to several Enterobacteriaceae (different Escherichia coli strains, Salmonella typhimurium, Shigella flexneri 2a) could be shown. The method was validated as a resilient process analytical technology (PAT) tool for the assessment of E-lysis and for particle counting during 20-l batch processes for the production of Escherichia coli Nissle 1917 BGs.
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Affiliation(s)
- Timo Langemann
- BIRD-C GmbH & Co KG, Dr.-Bohr-Gasse 2-8, A-1030, Vienna, Austria.,RCPE-Research Center Pharmaceutical Engineering GmbH, Inffeldgasse 13, A-8010, Graz, Austria
| | | | - Andrea Meitz
- RCPE-Research Center Pharmaceutical Engineering GmbH, Inffeldgasse 13, A-8010, Graz, Austria
| | - Werner Lubitz
- BIRD-C GmbH & Co KG, Dr.-Bohr-Gasse 2-8, A-1030, Vienna, Austria.,Center of Molecular Biology, University of Vienna, Dr.-Bohr-Gasse 9, A-1030, Vienna, Austria
| | - Christoph Herwig
- Research Division Biochemical Engineering, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1A 166/4, A-1060, Vienna, Austria.
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45
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Upadhyay A, Fontes F, Gonzalez-Juarrero M, McNeil MR, Crans DC, Jackson M, Crick DC. Partial Saturation of Menaquinone in Mycobacterium tuberculosis: Function and Essentiality of a Novel Reductase, MenJ. ACS CENTRAL SCIENCE 2015; 1:292-302. [PMID: 26436137 PMCID: PMC4582327 DOI: 10.1021/acscentsci.5b00212] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 05/12/2023]
Abstract
Menaquinone (MK) with partially saturated isoprenyl moieties is found in a wide range of eubacteria and Archaea. In many Gram-positive organisms, including mycobacteria, it is the double bond found in the β-isoprene unit that is reduced. Mass spectral characterization of menaquinone from mycobacterial knockout strains and heterologous expression hosts demonstrates that Rv0561c (designated menJ) encodes an enzyme which reduces the β-isoprene unit of menaquinone in Mycobacterium tuberculosis, forming the predominant form of menaquinone found in mycobacteria. MenJ is highly conserved in mycobacteria species but is not required for growth in culture. Disruption of menJ reduces mycobacterial electron transport efficiency by 3-fold, but mycobacteria are able to maintain ATP levels by increasing the levels of the total menaquinone in the membrane; however, MenJ is required for M. tuberculosis survival in host macrophages. Thus, MK with partially hydrogenated isoprenyl moieties represents a novel virulence factor and MenJ is a contextually essential enzyme and a potential drug target in pathogenic mycobacteria and other Gram-positive pathogens.
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Affiliation(s)
- Ashutosh Upadhyay
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Fabio
L. Fontes
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Mercedes Gonzalez-Juarrero
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Michael R. McNeil
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Debbie C. Crans
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Mary Jackson
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Dean C. Crick
- Department
of Microbiology, Immunology and Pathology, Department of Chemistry, and Cell and Molecular
Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
- Mycobacteria Research Laboratories,
Department of Microbiology, Immunology and Pathology, 1682 Campus
Delivery, Fort Collins, CO 80523, USA. E-mail: . Tel: (+1) 970 491 3308. Fax: (+1) 970 491 1815
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Ray S, Jindal B, Kunal K, Surolia A, Panda D. BT-benzo-29 inhibits bacterial cell proliferation by perturbing FtsZ assembly. FEBS J 2015; 282:4015-33. [PMID: 26258635 DOI: 10.1111/febs.13403] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/16/2015] [Accepted: 08/05/2015] [Indexed: 01/02/2023]
Abstract
We have identified a potent antibacterial agent N-(4-sec-butylphenyl)-2-(thiophen-2-yl)-1H-benzo[d]imidazole-4-carboxamide (BT-benzo-29) from a library of benzimidazole derivatives that stalled bacterial division by inhibiting FtsZ assembly. A short (5 min) exposure of BT-benzo-29 disassembled the cytokinetic Z-ring in Bacillus subtilis cells without affecting the cell length and nucleoids. BT-benzo-29 also perturbed the localization of early and late division proteins such as FtsA, ZapA and SepF at the mid-cell. Further, BT-benzo-29 bound to FtsZ with a dissociation constant of 24 ± 3 μm and inhibited the assembly and GTPase activity of purified FtsZ. A docking analysis suggested that BT-benzo-29 may bind to FtsZ at the C-terminal domain near the T7 loop. BT-benzo-29 displayed significantly weaker inhibitory effects on the assembly and GTPase activity of two mutants (L272A and V275A) of FtsZ supporting the prediction of the docking analysis. Further, BT-benzo-29 did not appear to inhibit DNA duplication and nucleoid segregation and it did not perturb the membrane potential of B. subtilis cells. The results suggested that BT-benzo-29 exerts its potent antibacterial activity by inhibiting FtsZ assembly. Interestingly, BT-benzo-29 did not affect the membrane integrity of mammalian red blood cells. BT-benzo-29 bound to tubulin with a much weaker affinity than FtsZ and exerted significantly weaker effects on mammalian cells than on the bacterial cells indicating that the compound may have a strong antibacterial potential.
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Affiliation(s)
- Shashikant Ray
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Bhavya Jindal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Kishore Kunal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Avadhesha Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Dulal Panda
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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47
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Dreier J, Ruggerone P. Interaction of antibacterial compounds with RND efflux pumps in Pseudomonas aeruginosa. Front Microbiol 2015; 6:660. [PMID: 26217310 PMCID: PMC4495556 DOI: 10.3389/fmicb.2015.00660] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/16/2015] [Indexed: 01/14/2023] Open
Abstract
Pseudomonas aeruginosa infections are becoming increasingly difficult to treat due to intrinsic antibiotic resistance and the propensity of this pathogen to accumulate diverse resistance mechanisms. Hyperexpression of efflux pumps of the Resistance-Nodulation-Cell Division (RND)-type multidrug efflux pumps (e.g., MexAB-OprM), chromosomally encoded by mexAB-oprM, mexCD-oprJ, mexEF-oprN, and mexXY (-oprA) is often detected in clinical isolates and contributes to worrying multi-drug resistance phenotypes. Not all antibiotics are affected to the same extent by the aforementioned RND efflux pumps. The impact of efflux on antibiotic activity varies not only between different classes of antibiotics but also between members of the same family of antibiotics. Subtle differences in physicochemical features of compound-pump and compound-solvent interactions largely determine how compounds are affected by efflux activity. The combination of different high-resolution techniques helps to gain insight into the functioning of these molecular machineries. This review discusses substrate recognition patterns based on experimental evidence and computer simulations with a focus on MexB, the pump subunit of the main RND transporter in P. aeruginosa.
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Affiliation(s)
- Jürg Dreier
- Basilea Pharmaceutica International Ltd.,Basel, Switzerland
| | - Paolo Ruggerone
- Dipartimento di Fisica, Università di Cagliari – Cittadella UniversitariaMonserrato, Italy
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48
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Boda SK, Bajpai I, Basu B. Inhibitory effect of direct electric field and HA-ZnO composites on S. aureus biofilm formation. J Biomed Mater Res B Appl Biomater 2015; 104:1064-75. [PMID: 26014126 DOI: 10.1002/jbm.b.33455] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/09/2015] [Accepted: 05/02/2015] [Indexed: 11/05/2022]
Abstract
In addressing the issue of prosthetic infection, we demonstrate herein how direct electric field (DC EF) stimulation can effectively inhibit biofilm formation, when pathogenic Staphylococcus aureus (MRSA, USA 300) are grown on HA-xZnO (x = 0, 5, 7.5, and 10 wt %) biocomposites in vitro. After bacterial preincubation for 4 h, a low intensity DC EF (1V/cm) was applied for different time periods (t = 6, 12, 18, and 24 h). The bacterial viability and biofilm maturation were evaluated by a combination of biochemical assays, fluorescence/confocal microscopy, and flow cytometry. The results confirm a time-dependent and composition-independent decrease in bacterial viability and biofilm formation on HA-xZnO composites w.r.t EF-treated HA. Flow cytometry analysis indicated that 12 h EF application resulted in membrane depolarization of ∼35% of S. aureus populations on HA-xZnO composites. The live/dead assay results revealed ∼60% decline in viable bacterial numbers with a concomitant 3.5-fold increase in the production of reactive oxygen species (ROS) after 18 h of EF. The loss in bacterial viability and biofilm instability is due to the synergistic bactericidal action of ZnO and EF. Taken together, the use of engineered biomaterial substrate with antimicrobial reinforcement coupled with continuous low intensity EF application can be adopted to treat prosthetic implant associated infection. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1064-1075, 2016.
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Affiliation(s)
- Sunil Kumar Boda
- Laboratory for Biomaterials, Materials Research Center, Indian Institute of Science, Bangalore, 560012, India
| | - Indu Bajpai
- Laboratory for Biomaterials, Materials Research Center, Indian Institute of Science, Bangalore, 560012, India.,School of Materials Science and Engineering, Yeungnam University, Gyeongsan, Gyeongbuk, 712749, South Korea
| | - Bikramjit Basu
- Laboratory for Biomaterials, Materials Research Center, Indian Institute of Science, Bangalore, 560012, India.,Bio-Engineering Program, Indian Institute of Science, Bangalore, 560012, India
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49
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Carvalho F, Atilano ML, Pombinho R, Covas G, Gallo RL, Filipe SR, Sousa S, Cabanes D. L-Rhamnosylation of Listeria monocytogenes Wall Teichoic Acids Promotes Resistance to Antimicrobial Peptides by Delaying Interaction with the Membrane. PLoS Pathog 2015; 11:e1004919. [PMID: 26001194 PMCID: PMC4441387 DOI: 10.1371/journal.ppat.1004919] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/27/2015] [Indexed: 11/29/2022] Open
Abstract
Listeria monocytogenes is an opportunistic Gram-positive bacterial pathogen responsible for listeriosis, a human foodborne disease. Its cell wall is densely decorated with wall teichoic acids (WTAs), a class of anionic glycopolymers that play key roles in bacterial physiology, including protection against the activity of antimicrobial peptides (AMPs). In other Gram-positive pathogens, WTA modification by amine-containing groups such as D-alanine was largely correlated with resistance to AMPs. However, in L. monocytogenes, where WTA modification is achieved solely via glycosylation, WTA-associated mechanisms of AMP resistance were unknown. Here, we show that the L-rhamnosylation of L. monocytogenes WTAs relies not only on the rmlACBD locus, which encodes the biosynthetic pathway for L-rhamnose, but also on rmlT encoding a putative rhamnosyltransferase. We demonstrate that this WTA tailoring mechanism promotes resistance to AMPs, unveiling a novel link between WTA glycosylation and bacterial resistance to host defense peptides. Using in vitro binding assays, fluorescence-based techniques and electron microscopy, we show that the presence of L-rhamnosylated WTAs at the surface of L. monocytogenes delays the crossing of the cell wall by AMPs and postpones their contact with the listerial membrane. We propose that WTA L-rhamnosylation promotes L. monocytogenes survival by decreasing the cell wall permeability to AMPs, thus hindering their access and detrimental interaction with the plasma membrane. Strikingly, we reveal a key contribution of WTA L-rhamnosylation for L. monocytogenes virulence in a mouse model of infection. Listeria monocytogenes is a foodborne bacterial pathogen that preferentially infects immunocompromised hosts, eliciting a severe and often lethal disease. In humans, clinical manifestations range from asymptomatic intestinal carriage and gastroenteritis to harsher systemic states of the disease such as sepsis, meningitis or encephalitis, and fetal infections. The surface of L. monocytogenes is decorated with wall teichoic acids (WTAs), a class of carbohydrate-based polymers that contributes to cell surface-related events with implications in physiological processes, such as bacterial division or resistance to antimicrobial peptides (AMPs). The addition of other molecules to the backbone of WTAs modulates their chemical properties and consequently their functionality. In this context, we studied the role of WTA tailoring mechanisms in L. monocytogenes, whose WTAs are strictly decorated with monosaccharides. For the first time, we link WTA glycosylation with AMP resistance by showing that the decoration of L. monocytogenes WTAs with l-rhamnose confers resistance to host defense peptides. We suggest that this resistance is based on changes in the permeability of the cell wall that delay its crossing by AMPs and therefore promote the protection of the bacterial membrane integrity. Importantly, we also demonstrate the significance of this WTA modification in L. monocytogenes virulence.
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Affiliation(s)
- Filipe Carvalho
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Magda L Atilano
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rita Pombinho
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Gonçalo Covas
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Richard L Gallo
- Division of Dermatology, Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Sérgio R Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sandra Sousa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal
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Reineke K, Sevenich R, Hertwig C, Janßen T, Fröhling A, Knorr D, Wieler LH, Schlüter O. Comparative study on the high pressure inactivation behavior of the Shiga toxin-producing Escherichia coli O104:H4 and O157:H7 outbreak strains and a non-pathogenic surrogate. Food Microbiol 2015; 46:184-194. [DOI: 10.1016/j.fm.2014.07.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 07/01/2014] [Accepted: 07/26/2014] [Indexed: 12/13/2022]
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