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Yin Z, Feng S, Tong Y, Yang H. Adaptive mechanism of Acidithiobacillus thiooxidans CCTCC M 2012104 under stress during bioleaching of low-grade chalcopyrite based on physiological and comparative transcriptomic analysis. ACTA ACUST UNITED AC 2019; 46:1643-1656. [DOI: 10.1007/s10295-019-02224-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 08/07/2019] [Indexed: 11/27/2022]
Abstract
Abstract
Acidithiobacillus thiooxidans (A. thiooxidans) is often used for sulfur-bearing ores bioleaching, but its adaptive mechanism to harsh environments remains unclear. Here, we explored the adaptive mechanism of A. thiooxidans in the process of low-grade chalcopyrite bioleaching based on the physiology and comparative transcriptome analysis. It was indicated that A. thiooxidans maintains intracellular pH homeostasis by regulating unsaturated fatty acids, especially cyclopropane fatty acids, intracellular ATP, amino acid metabolism, and antioxidant factors. Comparative transcriptome analysis indicated that the key genes involved in sulfur oxidation, sor and soxABXYZ, were significantly up-regulated, generating more energy to resist extreme environmental stress by more active sulfur metabolism. Confocal laser scanning microscope analysis found that down-regulation of flagellar-related genes was likely to promote the biofilm formation. System-level understanding of leaching microorganisms under extreme stress can contribute to the evolution of these extremophiles via genetic engineering modification work, which further improves bioleaching in future.
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Affiliation(s)
- Zongwei Yin
- The Key Laboratory of Industrial Biotechnology Ministry of Education Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 School of Biotechnology Jiangnan University 1800 Lihu Road Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University) Ministry of Education Wuxi People’s Republic of China
| | - Shoushuai Feng
- The Key Laboratory of Industrial Biotechnology Ministry of Education Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 School of Biotechnology Jiangnan University 1800 Lihu Road Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University) Ministry of Education Wuxi People’s Republic of China
| | - Yanjun Tong
- grid.258151.a 0000 0001 0708 1323 State Key Laboratory of Food Science and Technology Jiangnan University Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 School of Food Science and Technology Jiangnan University 1800 Lihu Road Wuxi People’s Republic of China
| | - Hailin Yang
- The Key Laboratory of Industrial Biotechnology Ministry of Education Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 School of Biotechnology Jiangnan University 1800 Lihu Road Wuxi People’s Republic of China
- grid.258151.a 0000 0001 0708 1323 Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University) Ministry of Education Wuxi People’s Republic of China
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Mechanical stress compromises multicomponent efflux complexes in bacteria. Proc Natl Acad Sci U S A 2019; 116:25462-25467. [PMID: 31772020 DOI: 10.1073/pnas.1909562116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Physical forces have a profound effect on growth, morphology, locomotion, and survival of organisms. At the level of individual cells, the role of mechanical forces is well recognized in eukaryotic physiology, but much less is known about prokaryotic organisms. Recent findings suggest an effect of physical forces on bacterial shape, cell division, motility, virulence, and biofilm initiation, but it remains unclear how mechanical forces applied to a bacterium are translated at the molecular level. In Gram-negative bacteria, multicomponent protein complexes can form rigid links across the cell envelope and are therefore subject to physical forces experienced by the cell. Here we manipulate tensile and shear mechanical stress in the bacterial cell envelope and use single-molecule tracking to show that octahedral shear (but not hydrostatic) stress within the cell envelope promotes disassembly of the tripartite efflux complex CusCBA, a system used by Escherichia coli to resist copper and silver toxicity. By promoting disassembly of this protein complex, mechanical forces within the cell envelope make the bacteria more susceptible to metal toxicity. These findings demonstrate that mechanical forces can inhibit the function of cell envelope protein assemblies in bacteria and suggest the possibility that other multicomponent, transenvelope efflux complexes may be sensitive to mechanical forces including complexes involved in antibiotic resistance, cell division, and translocation of outer membrane components. By modulating the function of proteins within the cell envelope, mechanical stress has the potential to regulate multiple processes required for bacterial survival and growth.
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Metabolic adaptability shifts of cell membrane fatty acids of Komagataeibacter hansenii HDM1-3 improve acid stress resistance and survival in acidic environments. J Ind Microbiol Biotechnol 2019; 46:1491-1503. [PMID: 31512094 DOI: 10.1007/s10295-019-02225-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/07/2019] [Indexed: 12/17/2022]
Abstract
Komagataeibacter hansenii HDM1-3 (K. hansenii HDM1-3) has been widely applied for producing bacterial cellulose (BC). The yield of BC has been frequently limited by the acidification during sugar metabolism, due to the generation of organic acids such as acetic acid. In this study, the acid resistance mechanism of K. hansenii HDM1-3 has been investigated from the aspect of metabolic adaptability of cell membrane fatty acids. Firstly, we observed that the survival rate of K. hansenii HDM1-3 was decreased with lowered pH values (adjusted with acetic acids), accompanied by increased leakage rate. Secondly, the cell membrane adaptability in response to acid stress was evaluated, including the variations of cell membrane fluidity and fatty acid composition. The proportion of unsaturated fatty acids was increased (especially, C18-1w9c and C19-Cyc), unsaturation degree and chain length of fatty acids were also increased. Thirdly, the potential molecular regulation mechanism was further elucidated. Under acid stress, the fatty acid synthesis pathway was involved in the structure and composition variations of fatty acids, which was proved by the activation of both fatty acid dehydrogenase (des) and cyclopropane fatty acid synthase (cfa) genes, as well as the addition of exogenous fatty acids. The fatty acid synthesis of K. hansenii HDM1-3 may be mediated by the activation of two-component sensor signaling pathways in response to the acid stress. The acid resistance mechanism of K. hansenii HDM1-3 adds to our knowledge of the acid stress adaptation, which may facilitate the development of new strategies for improving the industrial performance of this species under acid stress.
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54
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Dong LJ, Lai YJ, Yu SJ, Liu JF. Speciation Analysis of the Uptake and Biodistribution of Nanoparticulate and Ionic Silver in Escherichia coli. Anal Chem 2019; 91:12525-12530. [DOI: 10.1021/acs.analchem.9b03359] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Li-Jie Dong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Jian Lai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Su-Juan Yu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Jing-Fu Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Fernandez M, Paulucci NS, Peppino Margutti M, Biasutti AM, Racagni GE, Villasuso AL, Agostini E, González PS. Membrane Rigidity and Phosphatidic Acid (PtdOH) Signal: Two Important Events in Acinetobacter guillouiae SFC 500-1A Exposed to Chromium(VI) and Phenol. Lipids 2019; 54:557-570. [PMID: 31475368 DOI: 10.1002/lipd.12187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 11/06/2022]
Abstract
The remodeling of membrane lipids is a mechanism that allows microorganisms to survive in unfavorable environments such as industrial effluents, which often contain inorganic and organic pollutants, like chromium and phenol. In the present work, we evaluated the effect of Cr(VI) and phenol on the membrane of Acinetobacter guillouiae SFC 500-1A, a bacterial strain isolated from tannery sediments where such pollutants can be found. The presence of lipid kinases and phospholipases and the changes in their activities under exposure to these pollutants were determined. Cr(VI) and Cr(VI) + phenol caused the membrane to become more rigid for up to 16 h after exposure. This could be due to an increase in cardiolipin (Ptd2 Gro) and a decrease in phosphatidylethanolamine (PtdEtn), which are indicative of more order and rigidity in the membrane. Increased phospholipase A activity (PLA, EC 3.1.1.4) could be responsible for the decrease in PtdEtn levels. Moreover, our results indicate that Cr(VI) and Cr(VI) + phenol trigger the phosphatidic acid (PtdOH) signal. The finding of significantly increased phosphatidylinositol-4-phosphate (PtdIns-4-P) levels means this is likely achieved via PtdIns-PLC/DGK. This report provides the first evidence that A. guillouiae SFC 500-1A is able to sense Cr(VI) and phenol, transduce this signal through changes in the physical state of the membrane, and trigger lipid-signaling events.
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Affiliation(s)
- Marilina Fernandez
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Natalia S Paulucci
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Micaela Peppino Margutti
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Alicia M Biasutti
- Departamento de Química-FCEFQyN, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Graciela E Racagni
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Ana L Villasuso
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Elizabeth Agostini
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Paola S González
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
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56
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Scoma A, Garrido-Amador P, Nielsen SD, Røy H, Kjeldsen KU. The Polyextremophilic Bacterium Clostridium paradoxum Attains Piezophilic Traits by Modulating Its Energy Metabolism and Cell Membrane Composition. Appl Environ Microbiol 2019; 85:e00802-19. [PMID: 31126939 PMCID: PMC6643245 DOI: 10.1128/aem.00802-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 05/13/2019] [Indexed: 11/20/2022] Open
Abstract
In polyextremophiles, i.e., microorganisms growing preferentially under multiple extremes, synergistic effects may allow growth when application of the same extremes alone would not. High hydrostatic pressure (HP) is rarely considered in studies of polyextremophiles, and its role in potentially enhancing tolerance to other extremes remains unclear. Here, we investigated the HP-temperature response in Clostridium paradoxum, a haloalkaliphilic moderately thermophilic endospore-forming bacterium, in the range of 50 to 70°C and 0.1 to 30 MPa. At ambient pressure, growth limits were extended from the previously reported 63°C to 70°C, defining C. paradoxum as an actual thermophile. Concomitant application of high HP and temperature compared to standard conditions (i.e., ambient pressure and 50°C) remarkably enhanced growth, with an optimum growth rate observed at 22 MPa and 60°C. HP distinctively defined C. paradoxum physiology, as at 22 MPa biomass, production increased by 75% and the release of fermentation products per cell decreased by >50% compared to ambient pressure. This metabolic modulation was apparently linked to an energy-preserving mechanism triggered by HP, involving a shift toward pyruvate as the preferred energy and carbon source. High HPs decreased cell damage, as determined by Syto9 and propidium iodide staining, despite no organic solute being accumulated intracellularly. A distinct reduction in carbon chain length of phospholipid fatty acids (PLFAs) and an increase in the amount of branched-chain PLFAs occurred at high HP. Our results describe a multifaceted, cause-and-effect relationship between HP and cell metabolism, stressing the importance of applying HP to define the boundaries for life under polyextreme conditions.IMPORTANCE Hydrostatic pressure (HP) is a fundamental parameter influencing biochemical reactions and cell physiology; however, it is less frequently applied than other factors, such as pH, temperature, and salinity, when studying polyextremophilic microorganisms. In particular, how HP affects microbial tolerance to other and multiple extremes remains unclear. Here, we show that under polyextreme conditions of high pH and temperature, Clostridium paradoxum demonstrates a moderately piezophilic nature as cultures grow to highest cell densities and most efficiently at a specific combination of temperature and HP. Our results highlight the importance of considering HP when exploring microbial physiology under extreme conditions and thus have implications for defining the limits for microbial life in nature and for optimizing industrial bioprocesses occurring under multiple extremes.
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Affiliation(s)
- Alberto Scoma
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | - Paloma Garrido-Amador
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | | | - Hans Røy
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | - Kasper Urup Kjeldsen
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
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57
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Zhang T, Shi XC, Xia Y, Mai L, Tremblay PL. Escherichia coli adaptation and response to exposure to heavy atmospheric pollution. Sci Rep 2019; 9:10879. [PMID: 31350435 PMCID: PMC6659633 DOI: 10.1038/s41598-019-47427-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 07/16/2019] [Indexed: 12/30/2022] Open
Abstract
90% of the world population is exposed to heavy atmospheric pollution. This is a major public health issue causing 7 million death each year. Air pollution comprises an array of pollutants such as particulate matters, ozone and carbon monoxide imposing a multifactorial stress on living cells. Here, Escherichia coli was used as model cell and adapted for 390 generations to atmospheric pollution to assess its long-term effects at the genetic, transcriptomic and physiological levels. Over this period, E. coli evolved to grow faster and acquired an adaptive mutation in rpoB, which encodes the RNA polymerase β subunit. Transcriptomic and biochemical characterization showed alteration of the cell membrane composition resulting in lesser permeability after the adaptation process. A second significant change in the cell wall structure of the adapted strain was the greater accumulation of the exopolysaccharides colanic acid and cellulose in the extracellular fraction. Results also indicated that amino acids homeostasis was involved in E. coli response to atmospheric pollutants. This study demonstrates that adaptive mutation with transformative physiological impact can be fixed in genome after exposure to atmospheric pollution and also provides a comprehensive portrait of the cellular response mechanisms involved.
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Affiliation(s)
- Tian Zhang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, P.R. China.,School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, P.R. China
| | - Xiao-Chen Shi
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, P.R. China.,School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, P.R. China
| | - Yangyang Xia
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, P.R. China
| | - Liqiang Mai
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, P.R. China
| | - Pier-Luc Tremblay
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, P.R. China. .,School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, P.R. China.
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58
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Fonseca F, Pénicaud C, Tymczyszyn EE, Gómez-Zavaglia A, Passot S. Factors influencing the membrane fluidity and the impact on production of lactic acid bacteria starters. Appl Microbiol Biotechnol 2019; 103:6867-6883. [DOI: 10.1007/s00253-019-10002-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/25/2019] [Accepted: 06/27/2019] [Indexed: 01/09/2023]
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59
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Armengol E, Domenech O, Fusté E, Pérez-Guillén I, Borrell JH, Sierra JM, Vinas M. Efficacy of combinations of colistin with other antimicrobials involves membrane fluidity and efflux machinery. Infect Drug Resist 2019; 12:2031-2038. [PMID: 31372011 PMCID: PMC6628955 DOI: 10.2147/idr.s207844] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/17/2019] [Indexed: 11/24/2022] Open
Abstract
Objective Despite its use was abandoned several decades ago, the polycationic peptide colistin has become the last hope to treat severe infections caused by multidrug-resistant Gram-negative bacteria. Thus, the development of colistin resistance may seriously compromise the efficacy of treatment. Moreover, colistin has high toxicity being dose dependent. A potentially effective strategy to avoid resistance may be to combine colistin with other antimicrobials. This may help in the rescue of old antimicrobials and in reducing toxic undesired effects. Methods Antimicrobial susceptibility determination, efflux machinery function measurements in different conditions and measurement of inhibition of the extrusion by colistin were performed. Moreover, modifications of anisotropy of the membranes by using fluorescent dyes was accomplished. Results Sub-inhibitory concentrations of colistin have a synergistic effect with several antimicrobials that act intracellularly (targeting protein synthesis and DNA replication). This effect was demonstrated through the uptake increases of acridine orange. in Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumanii but also in an intrinsically colistin-resistant species as Serratia marcescens. Measurements of the anisotropy of bacterial membranes, as a measure of membrane fluidity, showed significant changes indicative of colistin activity. Conclusion The alterations in the cellular efflux machinery that resulted in higher intracellular concentrations of acridine orange, and likely of other antimicrobials combined with data of membrane fluidity and measured synergism in vitro allow us to envisage the use of these combinations to fight infections caused by multidrug–resistant bacteria.
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Affiliation(s)
- E Armengol
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - O Domenech
- Department of Pharmacy, Pharmaceutical Technology and Physical-Chemistry, University of Barcelona, Barcelona, Spain
| | - E Fusté
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain.,Department of Public Health, Mental Health and Perinatal Nursing. School of Nursing, University of Barcelona, Barcelona, Spain
| | - I Pérez-Guillén
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - J H Borrell
- Department of Pharmacy, Pharmaceutical Technology and Physical-Chemistry, University of Barcelona, Barcelona, Spain
| | - J M Sierra
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - M Vinas
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
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60
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Engineering microbial membranes to increase stress tolerance of industrial strains. Metab Eng 2019; 53:24-34. [DOI: 10.1016/j.ymben.2018.12.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/29/2018] [Accepted: 12/29/2018] [Indexed: 12/29/2022]
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61
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Fetoni AR, Paciello F, Rolesi R, Paludetti G, Troiani D. Targeting dysregulation of redox homeostasis in noise-induced hearing loss: Oxidative stress and ROS signaling. Free Radic Biol Med 2019; 135:46-59. [PMID: 30802489 DOI: 10.1016/j.freeradbiomed.2019.02.022] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/04/2019] [Accepted: 02/18/2019] [Indexed: 12/20/2022]
Abstract
Hearing loss caused by exposure to recreational and occupational noise remains a worldwide disabling condition and dysregulation of redox homeostasis is the hallmark of cochlear damage induced by noise exposure. In this review we discuss the dual function of ROS to both promote cell damage (oxidative stress) and cell adaptive responses (ROS signaling) in the cochlea undergoing a stressful condition such as noise exposure. We focus on animal models of noise-induced hearing loss (NIHL) and on the function of exogenous antioxidants to maintaining a physiological role of ROS signaling by distinguishing the effect of exogenous "direct" antioxidants (i.e. CoQ10, NAC), that react with ROS to decrease oxidative stress, from the exogenous "indirect" antioxidants (i.e. nutraceutics and phenolic compounds) that can activate cellular redox enzymes through the Keap1-Nrf2-ARE pathway. The anti-inflammatory properties of Nrf2 signaling are discussed in relation to the ROS/inflammation interplay in noise exposure. Unveiling the mechanisms of ROS regulating redox-associated signaling pathways is essential in providing relevant targets for innovative and effective therapeutic strategies against NIHL.
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Affiliation(s)
- Anna Rita Fetoni
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy; CNR Institute of Cell Biology and Neurobiology, Monterotondo, Italy
| | - Fabiola Paciello
- Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy; CNR Institute of Cell Biology and Neurobiology, Monterotondo, Italy
| | - Rolando Rolesi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gaetano Paludetti
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Diana Troiani
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.
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Bouhlel Z, Arnold AA, Warschawski DE, Lemarchand K, Tremblay R, Marcotte I. Labelling strategy and membrane characterization of marine bacteria Vibrio splendidus by in vivo 2H NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:871-878. [DOI: 10.1016/j.bbamem.2019.01.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/03/2019] [Accepted: 01/31/2019] [Indexed: 01/15/2023]
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63
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Sakkos JK, Wackett LP, Aksan A. Enhancement of biocatalyst activity and protection against stressors using a microbial exoskeleton. Sci Rep 2019; 9:3158. [PMID: 30816335 PMCID: PMC6395662 DOI: 10.1038/s41598-019-40113-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 02/08/2019] [Indexed: 12/18/2022] Open
Abstract
Whole cell biocatalysts can perform numerous industrially-relevant chemical reactions. While they are less expensive than purified enzymes, whole cells suffer from inherent reaction rate limitations due to transport resistance imposed by the cell membrane. Furthermore, it is desirable to immobilize the biocatalysts to enable ease of separation from the reaction mixture. In this study, we used a layer-by-layer (LbL) self-assembly process to create a microbial exoskeleton which, simultaneously immobilized, protected, and enhanced the reactivity of a whole cell biocatalyst. As a proof of concept, we used Escherichia coli expressing homoprotocatechuate 2,3-dioxygenase (HPCD) as a model biocatalyst and coated it with up to ten alternating layers of poly(diallyldimethylammonium chloride) (PDADMAC) and silica. The microbial exoskeleton also protected the biocatalyst against a variety of external stressors including: desiccation, freeze/thaw, exposure to high temperatures, osmotic shock, as well as against enzymatic attack by lysozyme, and predation by protozoa. While we observed increased permeability of the outer membrane after exoskeleton deposition, this had a moderate effect on the reaction rate (up to two-fold enhancement). When the exoskeleton construction was followed by detergent treatment to permeabilize the cytoplasmic membrane, up to 15-fold enhancement in the reaction rate was reached. With the exoskeleton, we increased in the reaction rate constants as much as 21-fold by running the biocatalyst at elevated temperatures ranging from 40 °C to 60 °C, a supraphysiologic temperature range not accessible by unprotected bacteria.
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Affiliation(s)
- Jonathan K Sakkos
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Lawrence P Wackett
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
- The BioTechnology Institute, University of Minnesota, St. Paul, MN, 55108, USA
| | - Alptekin Aksan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
- The BioTechnology Institute, University of Minnesota, St. Paul, MN, 55108, USA.
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64
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Shelud'ko AV, Filip'echeva YA, Telesheva EM, Yevstigneyeva SS, Petrova LP, Katsy EI. Restoration of polar-flagellum motility and biofilm-forming capacity in the mmsB1 mutant of the alphaproteobacterium Azospirillum brasilense Sp245 points to a new role for a homologue of 3-hydroxyisobutyrate dehydrogenase. Can J Microbiol 2018; 65:144-154. [PMID: 30336067 DOI: 10.1139/cjm-2018-0481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The bacterium Azospirillum brasilense can swim and swarm owing to the rotation of a constitutive polar flagellum (Fla) and inducible lateral flagella, respectively. They also form biofilms on various interfaces. Experimental data on flagellar assembly and social behaviours in these bacteria are scarce. Here, for the first time, the chromosomal coding sequence mmsB1 for a homologue of 3-hydroxyisobutyrate dehydrogenase (protein accession Nos. ADT80774 and E7CWE2) was shown to play a role in the assembly of motile Fla and in biofilm biomass accumulation. In the previously obtained mutant SK039 of A. brasilense Sp245, an Omegon-Km insertion in mmsB1 was concurrent with changes in cell-surface properties and with suppression of Fla assembly (partial) and Fla-dependent motility (complete). Here, the immotile leaky Fla- mutant SK039 was complemented with the expression vector pRK415-borne mmsB1 gene of Sp245. In the complemented mutant, the elevated relative cell hydrophobicity and changed relative membrane fluidity of SK039 returned to the wild-type levels; also, biofilm biomass accumulation increased and even reached Sp245's levels under nutritionally rich conditions. In strain SK039 (pRK415-mmsB1), the percentage of cells with Fla became significantly higher than that in mutant SK039, and the Fla-driven swimming velocity was equal to that in strain Sp245.
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Affiliation(s)
- Andrei V Shelud'ko
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
| | - Yulia A Filip'echeva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
| | - Elizaveta M Telesheva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
| | - Stella S Yevstigneyeva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
| | - Lilia P Petrova
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
| | - Elena I Katsy
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.,Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia
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Adaptive Metabolism in Staphylococci: Survival and Persistence in Environmental and Clinical Settings. J Pathog 2018; 2018:1092632. [PMID: 30327733 PMCID: PMC6171259 DOI: 10.1155/2018/1092632] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/28/2018] [Accepted: 08/12/2018] [Indexed: 01/04/2023] Open
Abstract
Staphylococci are highly successful at colonizing a variety of dynamic environments, both nonpathogenic and those of clinical importance, and comprise the list of pathogens of global public health significance. Their remarkable survival and persistence can be attributed to a host of strategies, one of which is metabolic versatility—their ability to rapidly alter their metabolism in the presence of transient or long-term bacteriostatic and bactericidal conditions and facilitate cellular homeostasis. These attributes contribute to their widespread dissemination and challenging eradication particularly from clinical settings. The study of microbial behaviour at the metabolite level provides insight into mechanisms of survival and persistence under defined environmental and clinical conditions. This paper reviews the range of metabolic modulations that facilitate staphylococcal acclimatization and persistence in varying terrestrial and host conditions, and their public health ramifications in these settings.
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66
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Lessons in Membrane Engineering for Octanoic Acid Production from Environmental Escherichia coli Isolates. Appl Environ Microbiol 2018; 84:AEM.01285-18. [PMID: 30030228 DOI: 10.1128/aem.01285-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 07/10/2018] [Indexed: 01/01/2023] Open
Abstract
Fermentative production of many attractive biorenewable fuels and chemicals is limited by product toxicity in the form of damage to the microbial cell membrane. Metabolic engineering of the production organism can help mitigate this problem, but there is a need for identification and prioritization of the most effective engineering targets. Here, we use a set of previously characterized environmental Escherichia coli isolates with high tolerance and production of octanoic acid, a model membrane-damaging biorenewable product, as a case study for identifying and prioritizing membrane engineering strategies. This characterization identified differences in the membrane lipid composition, fluidity, integrity, and cell surface hydrophobicity from those of the lab strain MG1655. Consistent with previous publications, decreased membrane fluidity was associated with increased fatty acid production ability. Maintenance of high membrane integrity or longer membrane lipids seemed to be of less importance than fluidity. Cell surface hydrophobicity was also directly associated with fatty acid production titers, with the strength of this association demonstrated by plasmid-based expression of the multiple stress resistance outer membrane protein BhsA. This expression of bhsA was effective in altering hydrophobicity, but the direction and magnitude of the change differed between strains. Thus, additional strategies are needed to reliably engineer cell surface hydrophobicity. This work demonstrates the ability of environmental microbiological studies to impact the metabolic engineering design-build-test-learn cycle and possibly increase the economic viability of fermentative bioprocesses.IMPORTANCE The production of bulk fuels and chemicals in a bio-based fermentation process requires high product titers. This is often difficult to achieve, because many of the target molecules damage the membrane of the microbial cell factory. Engineering the composition of the membrane in order to decrease its vulnerability to this damage has proven to be an effective strategy for improving bioproduction, but additional strategies and engineering targets are needed. Here, we studied a small set of environmental Escherichia coli isolates that have higher production titers of octanoic acid, a model biorenewable chemical, than those of the lab strain MG1655. We found that membrane fluidity and cell surface hydrophobicity are strongly associated with improved octanoic acid production. Fewer genetic modification strategies have been demonstrated for tuning hydrophobicity relative to fluidity, leading to the conclusion that there is a need for expanding hydrophobicity engineering strategies in E. coli.
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67
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Wang QY, Zeng XA, Liu ZW, Brennan CS. Variations in cellular membrane fatty acid composition ofEscherichia coliin resistance to pulsed electric fields induced by eugenol. J FOOD PROCESS PRES 2018. [DOI: 10.1111/jfpp.13740] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Qian-Yi Wang
- School of Food Science and Engineering; South China University of Technology; Guangzhou China
- Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center); Guangzhou China
| | - Xin-An Zeng
- School of Food Science and Engineering; South China University of Technology; Guangzhou China
- Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center); Guangzhou China
| | - Zhi-Wei Liu
- College of Food Science and Technology; Hunan Agricultural University; Changsha China
| | - Charles S. Brennan
- Department of Wine, Food and Molecular Biosciences; Lincoln University; Lincoln New Zealand
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68
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Luo J, Song Z, Ning J, Cheng Y, Wang Y, Cui F, Shen Y, Wang M. The ethanol-induced global alteration in Arthrobacter simplex and its mutants with enhanced ethanol tolerance. Appl Microbiol Biotechnol 2018; 102:9331-9350. [DOI: 10.1007/s00253-018-9301-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/22/2018] [Accepted: 08/03/2018] [Indexed: 11/27/2022]
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69
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Man DKW, Kanno T, Manzo G, Robertson BD, Lam JKW, Mason AJ. Rifampin- or Capreomycin-Induced Remodeling of the Mycobacterium smegmatis Mycolic Acid Layer Is Mitigated in Synergistic Combinations with Cationic Antimicrobial Peptides. mSphere 2018; 3:e00218-18. [PMID: 30021876 PMCID: PMC6052339 DOI: 10.1128/msphere.00218-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 06/24/2018] [Indexed: 01/15/2023] Open
Abstract
The mycobacterial cell wall affords natural resistance to antibiotics. Antimicrobial peptides (AMPs) modify the surface properties of mycobacteria and can act synergistically with antibiotics from differing classes. Here, we investigate the response of Mycobacterium smegmatis to the presence of rifampin or capreomycin, either alone or in combination with two synthetic, cationic, α-helical AMPs that are distinguished by the presence (D-LAK120-HP13) or absence (D-LAK120-A) of a kink-inducing proline. Using a combination of high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) metabolomics, diphenylhexatriene (DPH) fluorescence anisotropy measurements, and laurdan emission spectroscopy, we show that M. smegmatis responds to challenge with rifampin or capreomycin by substantially altering its metabolism and, in particular, by remodeling the cell envelope. Overall, the changes are consistent with a reduction of trehalose dimycolate and an increase of trehalose monomycolate and are associated with increased rigidity of the mycolic acid layer observed following challenge by capreomycin but not rifampin. Challenge with D-LAK120-A or D-LAK120-HP13 induced no or modest changes, respectively, in mycomembrane metabolites and did not induce a significant increase in the rigidity of the mycolic acid layer. Furthermore, the response to rifampin or capreomycin was significantly reduced when these were combined with D-LAK120-HP13 and D-LAK120-A, respectively, suggesting a possible mechanism for the synergy of these combinations. The remodeling of the mycomembrane in M. smegmatis is therefore identified as an important countermeasure deployed against rifampin or capreomycin, but this can be mitigated and the efficacy of rifampin or capreomycin potentiated by combining the drug with AMPs.IMPORTANCE We have used a combined NMR metabolomics/biophysical approach to better understand differences in the mechanisms of two closely related antimicrobial peptides, as well as the response of the model organism Mycobacterium smegmatis to challenge with first- or second-line antibiotics used against mycobacterial pathogens. We show that, in addition to membrane damage, the triggering of oxidative stress may be an important part of the mechanism of action of one AMP. The metabolic shift that accompanied rifampin and, particularly, capreomycin challenge was associated with modest and more dramatic changes, respectively, in the mycomembrane, providing a rationale for how the response to one antibiotic may affect bacterial penetration and, hence, the action of another. This study presents the first insights into how antimicrobial peptides may operate synergistically with existing antibiotics whose efficacy is waning or sensitize MDR mycobacteria and/or latent mycobacterial infections to them, prolonging the useful life of these drugs.
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Affiliation(s)
- DeDe Kwun-Wai Man
- Institute of Pharmaceutical Sciences, School of Cancer & Pharmaceutical Sciences, King's College London, London, United Kingdom
- Department of Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Tokuwa Kanno
- Institute of Pharmaceutical Sciences, School of Cancer & Pharmaceutical Sciences, King's College London, London, United Kingdom
| | - Giorgia Manzo
- Institute of Pharmaceutical Sciences, School of Cancer & Pharmaceutical Sciences, King's College London, London, United Kingdom
| | - Brian D Robertson
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, United Kingdom
| | - Jenny K W Lam
- Department of Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - A James Mason
- Institute of Pharmaceutical Sciences, School of Cancer & Pharmaceutical Sciences, King's College London, London, United Kingdom
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70
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Changes in the lipid composition of Bradyrhizobium cell envelope reveal a rapid response to water deficit involving lysophosphatidylethanolamine synthesis from phosphatidylethanolamine in outer membrane. Res Microbiol 2018; 169:303-312. [DOI: 10.1016/j.resmic.2018.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022]
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71
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Cui S, Hang F, Liu X, Xu Z, Liu Z, Zhao J, Zhang H, Chen W. Effect of acids produced from carbohydrate metabolism in cryoprotectants on the viability of freeze-dried Lactobacillus and prediction of optimal initial cell concentration. J Biosci Bioeng 2018; 125:513-518. [DOI: 10.1016/j.jbiosc.2017.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/03/2017] [Accepted: 12/12/2017] [Indexed: 12/14/2022]
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72
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Shi Y, Yue X, An L. Integrated regulation triggered by a cryophyte ω-3 desaturase gene confers multiple-stress tolerance in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2131-2148. [PMID: 29432580 PMCID: PMC6019038 DOI: 10.1093/jxb/ery050] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 02/02/2018] [Indexed: 05/16/2023]
Abstract
ω-3 fatty acid desaturases (FADs) are thought to contribute to plant stress tolerance mainly through linolenic acid (C18:3)-induced membrane stabilization, but a comprehensive analysis of their roles in stress adaptation is lacking. Here, we isolated a microsomal ω-3 FAD gene (CbFAD3) from a cryophyte (Chorispora bungeana) and elucidated its functions in stress tolerance. CbFAD3, exhibiting a high identity to Arabidopsis AtFAD3, was up-regulated by abiotic stresses. Its functionality was verified by heterogonous expression in yeast. Overexpression of CbFAD3 in tobacco constitutively increased C18:3 in both leaves and roots, which maintained the membrane fluidity, and enhanced plant tolerance to cold, drought, and salt stresses. Notably, the constitutively increased C18:3 induced a sustained activation of plasma membrane Ca2+-ATPase, thereby, changing the stress-induced Ca2+ signaling. The reactive oxygen species (ROS) scavenging system, which was positively correlated with the level of C18:3, was also activated in the transgenic lines. Microarray analysis showed that CbFAD3-overexpressing plants increased the expression of stress-responsive genes, most of which are affected by C18:3, Ca2+, or ROS. Together, CbFAD3 confers tolerance to multiple stresses in tobacco through the C18:3-induced integrated regulation of membrane, Ca2+, ROS, and stress-responsive genes. This is in contrast with previous observations that simply attribute stress tolerance to membrane stabilization.
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Affiliation(s)
- Yulan Shi
- Extreme Stress Resistance and Biotechnology Laboratory, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, PR China
| | - Xiule Yue
- School of Life Sciences, Lanzhou University, Lanzhou, PR China
| | - Lizhe An
- Extreme Stress Resistance and Biotechnology Laboratory, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, PR China
- School of Life Sciences, Lanzhou University, Lanzhou, PR China
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73
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Evaluation of membrane fluidity of multidrug-resistant isolates of Escherichia coli and Staphylococcus aureus in presence and absence of antibiotics. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 181:150-156. [PMID: 29567316 DOI: 10.1016/j.jphotobiol.2018.03.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/29/2018] [Accepted: 03/04/2018] [Indexed: 11/24/2022]
Abstract
In the face of the serious problem of antimicrobial resistance and the global dissemination of multidrug-resistant (MDR) bacteria, it is relevant to deeply study such bacteria both genetically and phenotypically. It is well known that bacteria have the ability to modify the biophysical properties of their cytoplasmic membranes, namely fluidity, in order to survive and thrive in hostile environments. The aim of this study was to assess and compare the membrane fluidity among multidrug-resistant (MDR) isolates of Escherichia coli and Staphylococcus aureus in absence and in presence of antibiotics (ceftazidime or ciprofloxacin). The membrane fluidity was monitored at 24-h intervals up to three days and at the sixth day, by measuring the anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) and the generalized polarization (GP) of Laurdan (6-dodecanoyl-2-dimethylaminonaphthalene). The anisotropy values as well as the Laurdan excitation GP (GPexc) values obtained from all three E. coli strains (two MDR isolates and one susceptible reference strain) were quite similar and indicative of a very alike membrane phospholipid composition, regardless harboring or not resistance to multiple antimicrobials. Nonetheless, in the case of S. aureus, the anisotropy values were more increased in methicillin-resistant S. aureus (MRSA) isolates in comparison to the reference strain, meaning they have a less fluid membrane. Equally, GPexc values were statistically different among the three S. aureus strains and showed that the two MRSA isolates had more rigid membranes than the susceptible strain. The exposition of MDR isolates of S. aureus to subinhibitory concentrations of ciprofloxacin did not affect neither the anisotropy values nor the GPexc values, therefore, not altering membrane fluidity. Membrane integrity, assessed by the Live/Dead staining, of all strains and conditions studied was maintained over the six days. Thus, these preliminary studies on membrane properties of MDR isolates demonstrate that i) MRSA seem to have a more rigid membrane that susceptible S. aureus and ii) the presence of subinhibitory concentrations of antibiotics does not significantly alter the membrane fluidity of S. aureus, regardless being MDR or susceptible, but slightly affect the membrane fluidity of E. coli.
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74
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Singh VK, Sirobhushanam S, Ring RP, Singh S, Gatto C, Wilkinson BJ. Roles of pyruvate dehydrogenase and branched-chain α-keto acid dehydrogenase in branched-chain membrane fatty acid levels and associated functions in Staphylococcus aureus. J Med Microbiol 2018; 67:570-578. [PMID: 29498620 DOI: 10.1099/jmm.0.000707] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Membrane fluidity to a large extent is governed by the presence of branched-chain fatty acids (BCFAs). Branched-chain α-keto acid dehydrogenase (BKD) is the key enzyme in BCFA synthesis. A Staphylococcus aureus BKD-deficient strain still produced substantial levels of BCFAs. Pyruvate dehydrogenase (PDH) with structural similarity to BKD has been speculated to contribute to BCFAs in S. aureus. METHODOLOGY This study was carried out using BKD-, PDH- and BKD : PDH-deficient derivatives of methicillin-resistant S. aureus strain JE2. Differences in growth kinetics were evaluated spectrophotometrically, membrane BCFAs using gas chromatography and membrane fluidity by fluorescence polarization. Carotenoid levels were estimated by measuring A465 of methanol extracts from 48 h cultures. MIC values were determined by broth microdilution.Results/Key findings. BCFAs made up 50 % of membrane fatty acids in wild-type but only 31 % in the BKD-deficient mutant. BCFA level was ~80 % in the PDH-deficient strain and 38 % in the BKD : PDH-deficient strain. BKD-deficient mutant showed decreased membrane fluidity, the PDH-deficient mutant showed increased membrane fluidity. The BKD- and PDH-deficient strains grew slower and the BKD : PDH-deficient strain grew slowest at 37 °C. However at 20 °C, the BKD- and BKD : PDH-deficient strains grew only a little followed by autolysis of these cells. The BKD-deficient strain produced higher levels of staphyloxanthin. The PDH-deficient and BKD : PDH-deficient strains produced very little staphyloxanthin. The BKD-deficient strain showed increased susceptibility to daptomycin. CONCLUSION The BCFA composition of the cell membrane in S. aureus seems to significantly impact cell growth, membrane fluidity and resistance to daptomycin.
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Affiliation(s)
- Vineet K Singh
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Sirisha Sirobhushanam
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Robert P Ring
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Saumya Singh
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Craig Gatto
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Brian J Wilkinson
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
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Membrane engineering via trans-unsaturated fatty acids production improves succinic acid production in Mannheimia succiniciproducens. J Ind Microbiol Biotechnol 2018; 45:555-566. [PMID: 29380151 DOI: 10.1007/s10295-018-2016-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 01/23/2018] [Indexed: 12/11/2022]
Abstract
Engineering of microorganisms to produce desired bio-products with high titer, yield, and productivity is often limited by product toxicity. This is also true for succinic acid (SA), a four carbon dicarboxylic acid of industrial importance. Acid products often cause product toxicity to cells through several different factors, membrane damage being one of the primary factors. In this study, cis-trans isomerase from Pseudomonas aeruginosa was expressed in Mannheimia succiniciproducens to produce trans-unsaturated fatty acid (TUFA) and to reinforce the cell membrane of M. succiniciproducens. The engineered strain showed significant decrease in membrane fluidity as production of TUFA enabled tight packing of fatty acids, which made cells to possess more rigid cell membrane. As a result, the membrane-engineered M. succiniciproducens strain showed higher tolerance toward SA and increased production of SA compared with the control strain without membrane engineering. The membrane engineering approach employed in this study will be useful for increasing tolerance to, and consequently enhancing production of acid products.
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76
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Marielle B, Sarrah G. Assessment of bacterial membrane fluidity by flow cytometry. J Microbiol Methods 2017; 143:50-57. [DOI: 10.1016/j.mimet.2017.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/13/2017] [Accepted: 10/14/2017] [Indexed: 10/18/2022]
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77
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Ding Q, Alborzi S, Bastarrachea LJ, Tikekar RV. Novel sanitization approach based on synergistic action of UV-A light and benzoic acid: Inactivation mechanism and a potential application in washing fresh produce. Food Microbiol 2017; 72:39-54. [PMID: 29407404 DOI: 10.1016/j.fm.2017.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/03/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022]
Abstract
Antimicrobial activity of the simultaneous UV-A light and benzoic acid (BA) treatment against stationary phase Escherichia coli O157:H7 was investigated. While 15 mM BA or UV-A light exposure for 30 min alone caused < 1 logarithmic reduction in the bacterial population, > 5 logarithmic reductions were induced by the simultaneous application of UV-A and 15 mM BA in 30 min, demonstrating a synergistic antimicrobial effect. Due to its ability to increase cell membrane permeability, addition of EDTA (1 mM) was able to decrease the required concentration of BA in the simultaneous treatment from 15 to 8 mM. Microbial inactivation was a result of simultaneous membrane damage, intracellular acidification, and intracellular oxidative stress. The simultaneous treatment was effective in the presence of organic load of up to 500 mg/L of chemical oxygen demand (COD) and was able to lower cross-contamination risk during simulated washing of spinach (Spinacia oleracea) without adversely affecting its color.
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Affiliation(s)
- Qiao Ding
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD 20742, United States
| | - Solmaz Alborzi
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD 20742, United States
| | - Luis J Bastarrachea
- Department of Nutrition, Dietetics and Food Sciences, Utah State University, 8700 Old Main Hill, Logan, UT 84322, United States
| | - Rohan V Tikekar
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD 20742, United States.
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78
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El Khoury M, Swain J, Sautrey G, Zimmermann L, Van Der Smissen P, Décout JL, Mingeot-Leclercq MP. Targeting Bacterial Cardiolipin Enriched Microdomains: An Antimicrobial Strategy Used by Amphiphilic Aminoglycoside Antibiotics. Sci Rep 2017; 7:10697. [PMID: 28878347 PMCID: PMC5587548 DOI: 10.1038/s41598-017-10543-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/11/2017] [Indexed: 01/31/2023] Open
Abstract
Some bacterial proteins involved in cell division and oxidative phosphorylation are tightly bound to cardiolipin. Cardiolipin is a non-bilayer anionic phospholipid found in bacterial inner membrane. It forms lipid microdomains located at the cell poles and division plane. Mechanisms by which microdomains are affected by membrane-acting antibiotics and the impact of these alterations on membrane properties and protein functions remain unclear. In this study, we demonstrated cardiolipin relocation and clustering as a result of exposure to a cardiolipin-acting amphiphilic aminoglycoside antibiotic, the 3′,6-dinonyl neamine. Changes in the biophysical properties of the bacterial membrane of P. aeruginosa, including decreased fluidity and increased permeability, were observed. Cardiolipin-interacting proteins and functions regulated by cardiolipin were impacted by the amphiphilic aminoglycoside as we demonstrated an inhibition of respiratory chain and changes in bacterial shape. The latter effect was characterized by the loss of bacterial rod shape through a decrease in length and increase in curvature. It resulted from the effect on MreB, a cardiolipin dependent cytoskeleton protein as well as a direct effect of 3′,6-dinonyl neamine on cardiolipin. These results shed light on how targeting cardiolipin microdomains may be of great interest for developing new antibacterial therapies.
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Affiliation(s)
- Micheline El Khoury
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, avenue E. Mounier 73, UCL B1.73.05, 1200, Brussels, Belgium
| | - Jitendriya Swain
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, avenue E. Mounier 73, UCL B1.73.05, 1200, Brussels, Belgium
| | - Guillaume Sautrey
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, avenue E. Mounier 73, UCL B1.73.05, 1200, Brussels, Belgium.,Université de Lorraine, UMR CNRS UL 7565, 1 Blvd. Des Aiguillettes, BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex, Nancy, France
| | - Louis Zimmermann
- Université Grenoble Alpes, Joseph Fourier/CNRS, Institut de Pharmacochimie Moléculaire, rue de la Chimie, F-38041, Grenoble, France
| | - Patrick Van Der Smissen
- Université Catholique de Louvain, de Duve Institute, avenue Hippocrate 75, UCL B1.75.05, 1200, Brussels, Belgium
| | - Jean-Luc Décout
- Université Grenoble Alpes, Joseph Fourier/CNRS, Institut de Pharmacochimie Moléculaire, rue de la Chimie, F-38041, Grenoble, France
| | - Marie-Paule Mingeot-Leclercq
- Université catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, avenue E. Mounier 73, UCL B1.73.05, 1200, Brussels, Belgium.
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79
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Damage to the microbial cell membrane during pyrolytic sugar utilization and strategies for increasing resistance. ACTA ACUST UNITED AC 2017; 44:1279-1292. [DOI: 10.1007/s10295-017-1958-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/20/2017] [Indexed: 11/25/2022]
Abstract
Abstract
Lignocellulosic biomass is an appealing feedstock for the production of biorenewable fuels and chemicals, and thermochemical processing is a promising method for depolymerizing it into sugars. However, trace compounds in this pyrolytic sugar syrup are inhibitory to microbial biocatalysts. This study demonstrates that hydrophobic inhibitors damage the cell membrane of ethanologenic Escherichia coli KO11+lgk. Adaptive evolution was employed to identify design strategies for improving pyrolytic sugar tolerance and utilization. Characterization of the resulting evolved strain indicates that increased resistance to the membrane-damaging effects of the pyrolytic sugars can be attributed to a glutamine to leucine mutation at position 29 of carbon storage regulator CsrA. This single amino acid change is sufficient for decreasing EPS protein production and increasing membrane integrity when exposed to pyrolytic sugars.
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80
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Guo Y, Tian X, Huang R, Tao X, Shah NP, Wei H, Wan C. A physiological comparative study of acid tolerance of Lactobacillus plantarum ZDY 2013 and L. plantarum ATCC 8014 at membrane and cytoplasm levels. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1295-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Varnava KG, Ronimus RS, Sarojini V. A review on comparative mechanistic studies of antimicrobial peptides against archaea. Biotechnol Bioeng 2017; 114:2457-2473. [PMID: 28734066 DOI: 10.1002/bit.26387] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 07/18/2017] [Indexed: 12/22/2022]
Abstract
Archaea was until recently considered as a third domain of life in addition to bacteria and eukarya but recent studies support the existence of only two superphyla (bacteria and archaea). The fundamental differences between archaeal, bacterial, and eukaryal cells are probably the main reasons for the comparatively lower susceptibility of archaeal strains to current antimicrobial agents. The possible emerging pathogenicity of archaea and the role of archaeal methanogens in methane emissions, a potent greenhouse gas, has led many researchers to examine the sensitivity patterns of archaea and make attempts to find agents that have significant anti-archaeal activity. Even though antimicrobial peptides (AMPs) are well known with several published reviews concerning their mode of action against bacteria and eukarya, to our knowledge, to date no reviews are available that focus on the action of these peptides against archaea. Herein, we present a review on all the peptides that have been tested against archaea. In addition, in an attempt to shed more light on possible future work that needs to be performed we have included a brief overview of the chemical characteristics, spectrum of activity, and the known mechanism of action of each of these peptides against bacteria and/or fungi. We also discuss the nature of and key physiological differences between Archaea, Bacteria, and Eukarya that are relevant to the development of anti-archaeal peptides. Despite our relatively limited knowledge about archaea, available data suggest that AMPs have an even broader spectrum of activity than currently recognized.
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Affiliation(s)
- Kyriakos G Varnava
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Ron S Ronimus
- Rumen Microbiology, AgResearch Ltd., Palmerston North, New Zealand
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82
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Vinçon-Laugier A, Cravo-Laureau C, Mitteau I, Grossi V. Temperature-Dependent Alkyl Glycerol Ether Lipid Composition of Mesophilic and Thermophilic Sulfate-Reducing Bacteria. Front Microbiol 2017; 8:1532. [PMID: 28848536 PMCID: PMC5552659 DOI: 10.3389/fmicb.2017.01532] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/28/2017] [Indexed: 11/13/2022] Open
Abstract
The occurrence of non-isoprenoid alkyl glycerol ether lipids in Bacteria and natural environments is increasingly being reported and the specificity and diagenetic stability of these lipids make them powerful biomarkers for biogeochemical and environmental studies. Yet the environmental controls on the biosynthesis of these peculiar membrane lipids remain poorly documented. Here, the lipid content of two mesophilic (Desulfatibacillum aliphaticivorans and Desulfatibacillum alkenivorans) and one thermophilic (Thermodesulfobacterium commune) sulfate-reducing bacteria-whose membranes are mostly composed of ether lipids-was investigated as a function of growth temperature (20-40°C and 54-84°C, respectively). For all strains, the cellular lipid content was lower at sub- or supra-optimal growth temperature, but the relative proportions of dialkyl glycerols, monoalkyl glycerols and fatty acids remained remarkably stable whatever the growth temperature. Rather than changing the proportions of the different lipid classes, the three strains responded to temperature changes by modifying the average structural composition of the alkyl and acyl chains constitutive of their membrane lipids. Major adaptive mechanisms concerned modifications of the level of branching and of the proportions of the different methyl branched lipids. Specifically, an increase in temperature induced mesophilic strains to produce less dimethyl branched dialkyl glycerols and 10-methyl branched lipids relative to linear structures, and the thermophilic strain to decrease the proportion of anteiso relative to iso methyl branched compounds. These modifications were in agreement with a regulation of the membrane fluidity. In one mesophilic and the thermophilic strains, a modification of the growth temperature further induced changes in the relative proportions of sn-2 vs sn-1 monoalkyl glycerols, suggesting an unprecedented mechanism of homeoviscous adaptation in Bacteria. Strong linear correlations observed between different ratios of alkyl glycerols and temperature allow to hypothesize the use of these specific lipids as indicators of temperature changes in the environment.
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Affiliation(s)
| | - Cristiana Cravo-Laureau
- Equipe Environnement et Microbiologie, UMR CNRS 5254, Université de Pau et des Pays de l'Adour, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les MatériauxPau, France
| | - Isabelle Mitteau
- Equipe Environnement et Microbiologie, UMR CNRS 5254, Université de Pau et des Pays de l'Adour, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les MatériauxPau, France
| | - Vincent Grossi
- Laboratoire de Géologie de Lyon, UMR CNRS 5276, Université Lyon 1Villeurbanne, France
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83
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Haddaji N, Mahdhi AK, Ismaiil MB, Bakhrouf A. Effect of environmental stress on cell surface and membrane fatty acids of Lactobacillus plantarum. Arch Microbiol 2017; 199:1243-1250. [DOI: 10.1007/s00203-017-1395-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 05/02/2017] [Accepted: 06/05/2017] [Indexed: 12/31/2022]
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84
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Siliakus MF, van der Oost J, Kengen SWM. Adaptations of archaeal and bacterial membranes to variations in temperature, pH and pressure. Extremophiles 2017; 21:651-670. [PMID: 28508135 PMCID: PMC5487899 DOI: 10.1007/s00792-017-0939-x] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 04/29/2017] [Indexed: 12/30/2022]
Abstract
The cytoplasmic membrane of a prokaryotic cell consists of a lipid bilayer or a monolayer that shields the cellular content from the environment. In addition, the membrane contains proteins that are responsible for transport of proteins and metabolites as well as for signalling and energy transduction. Maintenance of the functionality of the membrane during changing environmental conditions relies on the cell's potential to rapidly adjust the lipid composition of its membrane. Despite the fundamental chemical differences between bacterial ester lipids and archaeal ether lipids, both types are functional under a wide range of environmental conditions. We here provide an overview of archaeal and bacterial strategies of changing the lipid compositions of their membranes. Some molecular adjustments are unique for archaea or bacteria, whereas others are shared between the two domains. Strikingly, shared adjustments were predominantly observed near the growth boundaries of bacteria. Here, we demonstrate that the presence of membrane spanning ether-lipids and methyl branches shows a striking relationship with the growth boundaries of archaea and bacteria.
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Affiliation(s)
- Melvin F Siliakus
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
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85
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Wu C, Huang J, Zhou R. Genomics of lactic acid bacteria: Current status and potential applications. Crit Rev Microbiol 2017; 43:393-404. [PMID: 28502225 DOI: 10.1080/1040841x.2016.1179623] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Lactic acid bacteria (LAB) are widely used for the production of a variety of foods and feed raw materials where they contribute to flavor and texture of the fermented products. In addition, specific LAB strains are considered as probiotic due to their health-promoting effects in consumers. Recently, the genome sequencing of LAB is booming and the increased amount of published genomics data brings unprecedented opportunity for us to reveal the important traits of LAB. This review describes the recent progress on LAB genomics and special emphasis is placed on understanding the industry-related physiological features based on genomics analysis. Moreover, strategies to engineer metabolic capacity and stress tolerance of LAB with improved industrial performance are also discussed.
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Affiliation(s)
- Chongde Wu
- a College of Light Industry, Textile & Food Engineering, Sichuan University , Chengdu , China.,b Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University , Chengdu , China
| | - Jun Huang
- a College of Light Industry, Textile & Food Engineering, Sichuan University , Chengdu , China.,b Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University , Chengdu , China
| | - Rongqing Zhou
- a College of Light Industry, Textile & Food Engineering, Sichuan University , Chengdu , China.,b Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University , Chengdu , China
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86
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Lipid A structural modifications in extreme conditions and identification of unique modifying enzymes to define the Toll-like receptor 4 structure-activity relationship. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1439-1450. [PMID: 28108356 DOI: 10.1016/j.bbalip.2017.01.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 01/23/2023]
Abstract
Strategies utilizing Toll-like receptor 4 (TLR4) agonists for treatment of cancer, infectious diseases, and other targets report promising results. Potent TLR4 antagonists are also gaining attention as therapeutic leads. Though some principles for TLR4 modulation by lipid A have been described, a thorough understanding of the structure-activity relationship (SAR) is lacking. Only through a complete definition of lipid A-TLR4 SAR is it possible to predict TLR4 signaling effects of discrete lipid A structures, rendering them more pharmacologically relevant. A limited 'toolbox' of lipid A-modifying enzymes has been defined and is largely composed of enzymes from mesophile human and zoonotic pathogens. Expansion of this 'toolbox' will result from extending the search into lipid A biosynthesis and modification by bacteria living at the extremes. Here, we review the fundamentals of lipid A structure, advances in lipid A uses in TLR4 modulation, and the search for novel lipid A-modifying systems in extremophile bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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87
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Jin JC, Wu XJ, Xu J, Wang BB, Jiang FL, Liu Y. Ultrasmall silver nanoclusters: Highly efficient antibacterial activity and their mechanisms. Biomater Sci 2017; 5:247-257. [DOI: 10.1039/c6bm00717a] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study the antibacterial activities of bifunctional fluorescent DHLA-AgNCs against three types of bacteria, and the antibacterial mechanisms against differentE. colistrains are different.
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Affiliation(s)
- Jian-Cheng Jin
- State Key Laboratory of Virology
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- P. R. China
| | - Xiao-Juan Wu
- State Key Laboratory of Virology
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- P. R. China
| | - Juan Xu
- State Key Laboratory of Virology
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- P. R. China
| | - Bei-Bei Wang
- 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
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88
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Cesari AB, Paulucci NS, Biasutti MA, Reguera YB, Gallarato LA, Kilmurray C, Dardanelli MS. Reorganization of Azospirillum brasilense cell membrane is mediated by lipid composition adjustment to maintain optimal fluidity during water deficit. J Appl Microbiol 2016; 120:185-94. [PMID: 26535566 DOI: 10.1111/jam.12994] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 11/30/2022]
Abstract
AIMS We study the Azospirillum brasilense tolerance to water deficit and the dynamics of adaptive process at the level of the membrane. METHODS AND RESULTS Azospirillum brasilense was exposed to polyethylene glycol (PEG) growth and PEG shock. Tolerance, phospholipids and fatty acid (FA) composition and membrane fluidity were determined. Azospirillum brasilense was able to grow in the presence of PEG; however, its viability was reduced. Cells grown with PEG showed membrane fluidity similar to those grown without, the lipid composition was modified, increasing phosphatidylcholine and decreasing phosphatidylethanolamine amounts. The unsaturation FAs degree was reduced. The dynamics of the adaptive response revealed a decrease in fluidity 20 min after the addition of PEG, indicating that the PEG has a fluidizing effect on the hydrophobic region of the cell membrane. Fluidity returned to initial values after 60 min of PEG exposure. CONCLUSION Azospirillum brasilense is able to perceive osmotic changes by changing the membrane fluidity. This effect is offset by changes in the composition of membrane phospholipid and FA, contributing to the homeostasis of membrane fluidity under water deficit. SIGNIFICANCE AND IMPACT OF THE STUDY This knowledge can be used to develop new Azospirillum brasilense formulations showing an adapted membrane to water deficit.
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Affiliation(s)
- A B Cesari
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - N S Paulucci
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - M A Biasutti
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Y B Reguera
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - L A Gallarato
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - C Kilmurray
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - M S Dardanelli
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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89
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López G, Heredia R, Boeris P, Lucchesi G. Content of cardiolipin of the membrane and sensitivity to cationic surfactants in Pseudomonas putida. J Appl Microbiol 2016; 121:1004-14. [DOI: 10.1111/jam.13238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 06/27/2016] [Accepted: 07/13/2016] [Indexed: 02/04/2023]
Affiliation(s)
- G.A. López
- Departamento de Biología Molecular; Facultad de Ciencias Exactas; Físico-Químicas y Naturales; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
| | - R.M. Heredia
- Departamento de Biología Molecular; Facultad de Ciencias Exactas; Físico-Químicas y Naturales; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
| | - P.S. Boeris
- Departamento de Biología Molecular; Facultad de Ciencias Exactas; Físico-Químicas y Naturales; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
| | - G.I. Lucchesi
- Departamento de Biología Molecular; Facultad de Ciencias Exactas; Físico-Químicas y Naturales; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
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90
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Fozo EM, Rucks EA. The Making and Taking of Lipids: The Role of Bacterial Lipid Synthesis and the Harnessing of Host Lipids in Bacterial Pathogenesis. Adv Microb Physiol 2016; 69:51-155. [PMID: 27720012 DOI: 10.1016/bs.ampbs.2016.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In order to survive environmental stressors, including those induced by growth in the human host, bacterial pathogens will adjust their membrane physiology accordingly. These physiological changes also include the use of host-derived lipids to alter their own membranes and feed central metabolic pathways. Within the host, the pathogen is exposed to many stressful stimuli. A resulting adaptation is for pathogens to scavenge the host environment for readily available lipid sources. The pathogen takes advantage of these host-derived lipids to increase or decrease the rigidity of their own membranes, to provide themselves with valuable precursors to feed central metabolic pathways, or to impact host signalling and processes. Within, we review the diverse mechanisms that both extracellular and intracellular pathogens employ to alter their own membranes as well as their use of host-derived lipids in membrane synthesis and modification, in order to increase survival and perpetuate disease within the human host. Furthermore, we discuss how pathogen employed mechanistic utilization of host-derived lipids allows for their persistence, survival and potentiation of disease. A more thorough understanding of all of these mechanisms will have direct consequences for the development of new therapeutics, and specifically, therapeutics that target pathogens, while preserving normal flora.
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Affiliation(s)
- E M Fozo
- University of Tennessee, Knoxville, TN, United States.
| | - E A Rucks
- Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States.
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91
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Antibacterial Activity and Membrane-Disruptive Mechanism of 3-p-trans-Coumaroyl-2-hydroxyquinic Acid, a Novel Phenolic Compound from Pine Needles of Cedrus deodara, against Staphylococcus aureus. Molecules 2016; 21:molecules21081084. [PMID: 27548123 PMCID: PMC6273998 DOI: 10.3390/molecules21081084] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 12/22/2022] Open
Abstract
Recently, we reported that a novel phenolic compound isolated from Cedrus deodara, 3-p-trans-coumaroyl-2-hydroxyquinic acid (CHQA), exhibits a potent antioxidant activity. The present study aimed to evaluate the antibacterial activity of CHQA against eleven food-borne pathogens and to elucidate its mechanism of action against Staphylococcus aureus. The results from minimum inhibitory concentration (MIC) determinations showed that CHQA exhibited moderate inhibitory effects on all of the tested pathogens with MIC values ranging from 2.5-10 mg/mL. Membrane potential measurements and flow cytometric analysis demonstrated that CHQA damaged the cytoplasmic membrane of S. aureus, causing a significant membrane hyperpolarization with a loss of membrane integrity. Moreover, CHQA induced an increase in membrane fluidity and conformational changes in membrane protein of S. aureus, suggesting that CHQA probably acts on the cell membrane by interactions with membrane lipid and protein. Transmission electron microscopic observations further confirmed that CHQA disrupted the cell membrane of S. aureus and caused severe morphological changes, which even led to leakage of intracellular constituents. These findings indicated that CHQA could have the potential to serve as a natural antibacterial agent to control and prevent the growth of pathogens in food and in food-processing environments.
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92
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Wang LH, Wang MS, Zeng XA, Liu ZW. Temperature-mediated variations in cellular membrane fatty acid composition of Staphylococcus aureus in resistance to pulsed electric fields. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1791-800. [DOI: 10.1016/j.bbamem.2016.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/25/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
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93
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Wu Y, Bai J, Zhong K, Huang Y, Gao H. A dual antibacterial mechanism involved in membrane disruption and DNA binding of 2R,3R-dihydromyricetin from pine needles of Cedrus deodara against Staphylococcus aureus. Food Chem 2016; 218:463-470. [PMID: 27719936 DOI: 10.1016/j.foodchem.2016.07.090] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 06/09/2016] [Accepted: 07/12/2016] [Indexed: 01/01/2023]
Abstract
The antibacterial activity and mechanism of 2R,3R-dihydromyricetin (DMY) against Staphylococcus aureus were investigated. The minimum inhibitory concentration of DMY against S. aureus was 0.125mg/ml, and the growth inhibitory assay also revealed that DMY showed a potent antibacterial activity against S. aureus. Massive nucleotide leakage and flow cytometric analysis demonstrated that DMY disrupted the membrane integrity of S. aureus. Morphological changes and membrane hyperpolarization of S. aureus cells treated with DMY further suggested that DMY destroyed cell membrane. Meanwhile, DMY probably interacted with membrane lipids and proteins, causing a significant reduction in membrane fluidity and changes in conformation of membrane protein. Moreover, DMY could interact with S. aureus DNA through the groove binding mode. Overall, the results suggested that DMY could be applied as a candidate for the development of new food preservatives as it achieved bactericidal activity by damaging cell membrane and binding to intracellular DNA.
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Affiliation(s)
- Yanping Wu
- Department of Food Science and Technology, College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu 610065, China
| | - Jinrong Bai
- Department of Food Science and Technology, College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu 610065, China
| | - Kai Zhong
- Department of Food Science and Technology, College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu 610065, China
| | - Yina Huang
- Department of Public Health, West China Medical School, Sichuan University, Chengdu 610041, China.
| | - Hong Gao
- Department of Food Science and Technology, College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu 610065, China.
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94
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Gadea R, Fernández Fuentes MÁ, Pérez Pulido R, Gálvez A, Ortega E. Adaptive tolerance to phenolic biocides in bacteria from organic foods: Effects on antimicrobial susceptibility and tolerance to physical stresses. Food Res Int 2016; 85:131-143. [PMID: 29544828 DOI: 10.1016/j.foodres.2016.04.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/19/2016] [Accepted: 04/24/2016] [Indexed: 11/26/2022]
Abstract
The aim of the present study was to analyze the effects of step-wise exposure of biocide-sensitive bacteria from organic foods to phenolic biocides triclosan (TC) and hexachlorophene [2,2'-methylenebis(3,4,6-trichlorophenol)] (CF). The analysis included changes in the tolerance to the biocide itself, the tolerance to other biocides, and cross-resistance to clinically important antibiotics. The involvement of efflux mechanisms was also studied as well as the possible implication of modifications in cytoplasmic membrane fluidity in the resistance mechanisms. The influence of biocide tolerance on growth capacity of the adapted strains and on subsequent resistance to other physical stresses has also been analyzed. Repeated exposure of bacteria from organic foods to phenolic biocides resulted in most cases in partially increased tolerance to the same biocide, to dissimilar biocides and other antimicrobial compounds. Nine TC-adapted strains and six CF-adapted strains were able to develop high levels of biocide tolerance, and these were stable in the absence of biocide selective pressure. Most strains adapted to TC and one CF-adapted strain showed significantly higher anisotropy values than their corresponding wildtype strains, suggesting that changes in membrane fluidity could be involved in biocide adaptation. Exposure to gradually increasing concentrations of CF induced a decrease in heat tolerance. Biocide adaptation had no significant effects of gastric acid or bile resistance, suggesting that biocide adaptation should not influence survival in the gastrointestinal tract.
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Affiliation(s)
- Rebeca Gadea
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain
| | - Miguel Ángel Fernández Fuentes
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain
| | - Rubén Pérez Pulido
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain
| | - Antonio Gálvez
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain.
| | - Elena Ortega
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain
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95
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Antibacterial activity of curcumin via apoptosis-like response in Escherichia coli. Appl Microbiol Biotechnol 2016; 100:5505-14. [PMID: 26960318 DOI: 10.1007/s00253-016-7415-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/21/2016] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
Abstract
Curcumin, a naturally occurring phenolic compound, has been shown to exhibit antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, etc., but the mechanism remains unclear. The present study was designed to investigate the novel antibacterial mechanism of curcumin that shows an apoptosis-like response in E. coli. We found that curcumin induces membrane damage at relatively high concentrations, but there was no effect at the minimum inhibitory concentration (MIC). At the MIC, curcumin-treated cells displayed various apoptotic markers such as reactive oxygen species (ROS) accumulation, membrane depolarization, and Ca(2+) influx. Expression of RecA protein, which mediates a bacterial apoptosis-like response, was also increased by curcumin. In order to evaluate the influence of RecA on the appearance of other apoptotic markers, phosphatidylserine (PS) exposure and DNA fragmentation were examined and compared with a RecA deletion strain (ΔRecA). These markers were detected in E. coli wild-type cells, but not in ΔRecA cells. In conclusion, our data demonstrate that curcumin induces an apoptosis-like response in E. coli that involves RecA.
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96
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Marisa Heredia R, Sabrina Boeris P, Sebastián Liffourrena A, Fernanda Bergero M, Alberto López G, Inés Lucchesi G. Release of outer membrane vesicles in Pseudomonas putida as a response to stress caused by cationic surfactants. MICROBIOLOGY-SGM 2016; 162:813-822. [PMID: 26925774 DOI: 10.1099/mic.0.000265] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pseudomonas putida A (ATCC 12633), a degrader of cationic surfactants, releases outer membrane vesicles (OMVs) when grown with tetradecyltrimethylammonium bromide (TTAB) as the sole carbon, nitrogen and energy source. The OMVs exhibit a bilayer structure and were found to be composed of lipopolysaccharides, proteins and phospholipids (PLs) such as cardiolipin, phosphatidylcholine, phosphatidic acid and phosphatidylglycerol (PG). The OMVs showed a marked increase in the PG content, approximately 43 % higher than the amount registered in the parent cells from which the vesicles were derived. After growth of P. putida with TTAB, the amount of lipoprotein covalently cross-linked to the peptidoglycan showed a twofold decrease when compared with values found after growth without the surfactant [16 ± 2 and 28 ± 3 μg (mg cell envelope protein)- 1, respectively]. This decrease in the amount of lipoprotein can be related to areas of loss of contact between the outer membrane and the peptidoglycan and, therefore, to OMV production. In addition, due to its amphiphilic nature, TTAB can contribute to OMV biogenesis, through a physical mechanism, by induction of the curvature of the membrane. Taking into account that OVMs were produced when the cells were grown under external stress, caused by the surfactant, and that TTAB was detected in the vesicles [48 nmol TTAB (nmol PL)- 1], we concluded that this system of TTAB elimination is a mechanism that P. putida A (ATCC 12633) would utilize for alleviating stress caused by cationic surfactants.
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Affiliation(s)
- Romina Marisa Heredia
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
| | - Paola Sabrina Boeris
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
| | - Andrés Sebastián Liffourrena
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
| | - María Fernanda Bergero
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
| | - Gastón Alberto López
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
| | - Gloria Inés Lucchesi
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA Río Cuarto, Córdoba, Argentina
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97
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Wan C, Chen S, Wen L, Liu X, Lee DJ, Yang X. Biosynthesis, characterization and potentiality of lipopeptides produced by Bacillus flexus S1 without inductive carbon sources. RSC Adv 2016. [DOI: 10.1039/c6ra17510d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study newly isolated a bacterial stain ofBacillus flexusS1 which had abilities of synthesizing lipopeptides without any inductive operations, and thus it could effectively save operational procedures or cost.
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Affiliation(s)
- Chunli Wan
- Department of Environmental Science and Engineering
- Fudan University
- Shanghai 200433
- China
| | - Si Chen
- Department of Environmental Science and Engineering
- Fudan University
- Shanghai 200433
- China
| | - Lei Wen
- Department of Environmental Science and Engineering
- Fudan University
- Shanghai 200433
- China
| | - Xiang Liu
- Department of Environmental Science and Engineering
- Fudan University
- Shanghai 200433
- China
| | - Duu-Jong Lee
- Department of Chemical Engineering
- National Taiwan University of Science and Technology
- Taipei 106
- Taiwan
| | - Xue Yang
- State Key Laboratory of Pollution Control and Resources Reuse
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
- China
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98
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Huang R, Pan M, Wan C, Shah NP, Tao X, Wei H. Physiological and transcriptional responses and cross protection of Lactobacillus plantarum ZDY2013 under acid stress. J Dairy Sci 2015; 99:1002-1010. [PMID: 26627851 DOI: 10.3168/jds.2015-9993] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 08/27/2015] [Indexed: 01/20/2023]
Abstract
Acid tolerance responses (ATR) in Lactobacillus plantarum ZDY2013 were investigated at physiological and molecular levels. A comparison of composition of cell membrane fatty acids (CMFA) between acid-challenged and unchallenged cells showed that acid adaptation evoked a significantly higher percentage of saturated fatty acids and cyclopropane fatty acids in acid-challenged than in unchallenged cells. In addition, reverse transcription-quantitative PCR analysis in acid-adapted cells at different pH values (ranging from 3.0 to 4.0) indicated that several genes were differently regulated, including those related to proton pumps, amino acid metabolism, sugar metabolism, and class I and class III stress response pathways. Expression of genes involved in fatty acid synthesis and production of alkali was significantly upregulated. Upon exposure to pH 4.5 for 2 h, a higher survival rate (higher viable cell count) of Lactobacillus plantarum ZDY2013 was achieved following an additional challenge to 40 mM hydrogen peroxide for 60 min, but no difference in survival rate of cells was found with further challenge to heat, ethanol, or salt. Therefore, we concluded that the physiological and metabolic changes of acid-treated cells of Lactobacillus plantarum ZDY2013 help the cells resist damage caused by acid, and further initiated global response signals to bring the whole cell into a state of defense to other stress factors, especially hydrogen peroxide.
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Affiliation(s)
- Renhui Huang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China; Jiangxi-OAI Joint Research Institute, Nanchang University, 235 Nanjing Donglu, Nanchang 330047, P. R. China
| | - Mingfang Pan
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China; Jiangxi-OAI Joint Research Institute, Nanchang University, 235 Nanjing Donglu, Nanchang 330047, P. R. China
| | - Cuixiang Wan
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China.
| | - Nagendra P Shah
- Food and Nutritional Science, School of Biological Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Xueying Tao
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China; Jiangxi-OAI Joint Research Institute, Nanchang University, 235 Nanjing Donglu, Nanchang 330047, P. R. China
| | - Hua Wei
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China; Jiangxi-OAI Joint Research Institute, Nanchang University, 235 Nanjing Donglu, Nanchang 330047, P. R. China
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99
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Microscopic characterization of the bacterial cell envelope of Planococcus halocryophilus Or1 during subzero growth at −15 °C. Polar Biol 2015. [DOI: 10.1007/s00300-015-1826-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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100
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Yu H, Meng X, Aflakpui FWK, Luo L. A salt-induced butA gene of Tetragenococcus halophilus confers salt tolerance to Escherichia coli by heterologous expression of its dual copies. ANN MICROBIOL 2015. [DOI: 10.1007/s13213-015-1160-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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