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Trans-cinnamaldehyde inhibits Penicillium italicum by damaging mitochondria and inducing apoptosis mechanisms. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2022.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jin K, Xia H, Liu Y, Li J, Du G, Lv X, Liu L. Compartmentalization and transporter engineering strategies for terpenoid synthesis. Microb Cell Fact 2022; 21:92. [PMID: 35599322 PMCID: PMC9125818 DOI: 10.1186/s12934-022-01819-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 05/12/2022] [Indexed: 12/18/2022] Open
Abstract
Microbial cell factories for terpenoid synthesis form a less expensive and more environment-friendly approach than chemical synthesis and extraction, and are thus being regarded as mainstream research recently. Organelle compartmentalization for terpenoid synthesis has received much attention from researchers owing to the diverse physiochemical characteristics of organelles. In this review, we first systematically summarized various compartmentalization strategies utilized in terpenoid production, mainly plant terpenoids, which can provide catalytic reactions with sufficient intermediates and a suitable environment, while bypassing competing metabolic pathways. In addition, because of the limited storage capacity of cells, strategies used for the expansion of specific organelle membranes were discussed. Next, transporter engineering strategies to overcome the cytotoxic effects of terpenoid accumulation were analyzed. Finally, we discussed the future perspectives of compartmentalization and transporter engineering strategies, with the hope of providing theoretical guidance for designing and constructing cell factories for the purpose of terpenoid production.
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Ahmad A, Elisha IL, van Vuuren S, Viljoen A. Volatile phenolics: A comprehensive review of the anti-infective properties of an important class of essential oil constituents. PHYTOCHEMISTRY 2021; 190:112864. [PMID: 34311279 DOI: 10.1016/j.phytochem.2021.112864] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Historically, essential oils and their lead molecules have been extensively recognised for their anti-infective properties. In this context, certain volatile phenolics (VPs) have emerged as important antimicrobial compounds with excellent inhibitory activity against pathogenic bacteria and fungi, which further extends to drug-resistant and biofilm-forming micro-organisms. In this review, we aim to collate and discuss a number of published papers on the anti-infective activities of naturally occurring VPs with special emphasis on eugenol, isoeugenol, thymol and carvacrol, using Scopus Web of Science and PubMed databases. The biosynthesis and extraction of these VPs are discussed, while particular attention is given to their broad-spectrum antimicrobial activity and the mechanisms of action. We highlight combinational studies of the VPs with other phytocompounds and with commercially available drugs, which may be a promising and a rewarding future approach to combat antimicrobial resistance. These VPs alone, or concomitantly with other compounds or drugs, have the potential to be incorporated into different formulations for biomedical applications. An in-depth assessment of 2310 articles retrieved from the Scopus database spanning a 35-year period indicated 23.1% increase in global publication growth in VPs anti-infective research, with authors from Italy, Portugal and Austria dominating the research landscape. The dominant areas of investigations are identified as antimicrobial activity, antibacterial mechanism of action, antifungal mechanism of action, extraction methods and phytochemistry, use in the food industry, and for oral and dental anti-infective activity. Specific research areas, which require future attention include; antituberculosis research, nanoparticle formulation of antimicrobial active VP molecules, preclinical and clinical trials. The antimicrobial testing of isoeugenol was found to be the least studied of the VPs and this requires further attention.
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Affiliation(s)
- Aijaz Ahmad
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa; Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg, South Africa.
| | - Ishaku Leo Elisha
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa; Drug Development Section, Biochemistry Division, National Veterinary Research Institute, P.M.B. 01 Vom, Plateau State, Nigeria.
| | - Sandy van Vuuren
- Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, South Africa.
| | - Alvaro Viljoen
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa; SAMRC Herbal Drugs Research Unit, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa.
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Stress Resistance Development and Genome-Wide Transcriptional Response of Escherichia coli O157:H7 Adapted to Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde. Appl Environ Microbiol 2018; 84:AEM.01616-18. [PMID: 30217837 DOI: 10.1128/aem.01616-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/02/2018] [Indexed: 01/05/2023] Open
Abstract
Thymol, carvacrol, and trans-cinnamaldehyde are essential oil (EO) compounds with broad-spectrum antimicrobial activities against foodborne pathogens, including Escherichia coli O157:H7. However, little is known regarding direct resistance and cross-resistance development in E. coli O157:H7 after adaptation to sublethal levels of these compounds, and information is scarce on microbial adaptive responses at a molecular level. The present study demonstrated that E. coli O157:H7 was able to grow in the presence of sublethal thymol (1/2T), carvacrol (1/2C), or trans-cinnamaldehyde (1/2TC), displaying an extended lag phase duration and a lower maximum growth rate. EO-adapted cells developed direct resistance against lethal EO treatments and cross-resistance against heat (58°C) and oxidative (50 mM H2O2) stresses. However, no induction of acid resistance (simulated gastric fluid, pH 1.5) was observed. RNA sequencing revealed a large number (310 to 338) of differentially expressed (adjusted P value [Padj ], <0.05; fold change, ≥5) genes in 1/2T and 1/2C cells, while 1/2TC cells only showed 27 genes with altered expression. In accordance with resistance phenotypes, the genes related to membrane, heat, and oxidative stress responses and genes related to iron uptake and metabolism were upregulated. Conversely, virulence genes associated with motility, biofilm formation, and efflux pumps were repressed. This study demonstrated the development of direct resistance and cross-resistance and characterized whole-genome transcriptional responses in E. coli O157:H7 adapted to sublethal thymol, carvacrol, or trans-cinnamaldehyde. The data suggested that caution should be exercised when using EO compounds as food antimicrobials, due to the potential stress resistance development in E. coli O157:H7.IMPORTANCE The present study was designed to understand transcriptomic changes and the potential development of direct and cross-resistance in essential oil (EO)-adapted Escherichia coli O157:H7. The results demonstrated altered growth behaviors of E. coli O157:H7 during adaptation in sublethal thymol, carvacrol, and trans-cinnamaldehyde. Generally, EO-adapted bacteria showed enhanced resistance against subsequent lethal EO, heat, and oxidative stresses, with no induction of acid resistance in simulated gastric fluid. A transcriptomic analysis revealed the upregulation of related stress resistance genes and a downregulation of various virulence genes in EO-adapted cells. This study provides new insights into microbial EO adaptation behaviors and highlights the risk of resistance development in adapted bacteria.
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OuYang Q, Tao N, Jing G. Transcriptional profiling analysis of Penicillium digitatum, the causal agent of citrus green mold, unravels an inhibited ergosterol biosynthesis pathway in response to citral. BMC Genomics 2016; 17:599. [PMID: 27514516 PMCID: PMC4982135 DOI: 10.1186/s12864-016-2943-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/18/2016] [Indexed: 11/17/2022] Open
Abstract
Background Green mold caused by Penicillium digitatum is the most damaging postharvest diseases of citrus fruit. Previously, we have observed that citral dose-dependently inhibited the mycelial growth of P. digitatum, with the minimum inhibitory concentration (MIC) of 1.78 mg/mL, but the underlying molecular mechanism is barely understood. Results In this study, the transcriptional profiling of the control and 1/2MIC-citral treated P. digitatum mycelia after 30 min of exposure were analyzed by RNA-Seq. A total of 6355 genes, including 2322 up-regulated and 4033 down-regulated genes, were found to be responsive to citral. These genes were mapped to 155 KEGG pathways, mainly concerning mRNA surveillance, RNA polymerase, RNA transport, aminoacyl-tRNA biosynthesis, ABC transporter, glycolysis/gluconeogenesis, citrate cycle, oxidative phosphorylation, sulfur metabolism, nitrogen metabolism, inositol phosphate metabolism, fatty acid biosynthesis, unsaturated fatty acids biosynthesis, fatty acid metabolism, and steroid biosynthesis. Particularly, citral exposure affected the expression levels of five ergosterol biosynthetic genes (e.g. ERG7, ERG11, ERG6, ERG3 and ERG5), which corresponds well with the GC-MS results, the reduction in ergosterol content, and accumulation of massive lanosterol. In addition, ERG11, the gene responsible for lanosterol 14α-demethylase, was observed to be the key down-regulated gene in response to citral. Conclusion Our present finding suggests that citral could exhibit its antifungal activity against P. digitatum by the down-regulation of ergosterol biosynthesis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2943-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiuli OuYang
- School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China
| | - Nengguo Tao
- School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China.
| | - Guoxing Jing
- School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China
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Augmenting the Activity of Monoterpenoid Phenols against Fungal Pathogens Using 2-Hydroxy-4-methoxybenzaldehyde that Target Cell Wall Integrity. Int J Mol Sci 2015; 16:26850-70. [PMID: 26569223 PMCID: PMC4661847 DOI: 10.3390/ijms161125988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 10/27/2015] [Accepted: 11/02/2015] [Indexed: 12/15/2022] Open
Abstract
Disruption of cell wall integrity system should be an effective strategy for control of fungal pathogens. To augment the cell wall disruption efficacy of monoterpenoid phenols (carvacrol, thymol), antimycotic potency of benzaldehyde derivatives that can serve as chemosensitizing agents were evaluated against strains of Saccharomyces cerevisiae wild type (WT), slt2Δ and bck1Δ (mutants of the mitogen-activated protein kinase (MAPK) and MAPK kinase kinase, respectively, in the cell wall integrity pathway). Among fourteen compounds investigated, slt2Δ and bck1Δ showed higher susceptibility to nine benzaldehydes, compared to WT. Differential antimycotic activity of screened compounds indicated "structure-activity relationship" for targeting the cell wall integrity, where 2-hydroxy-4-methoxybenzaldehyde (2H4M) exhibited the highest antimycotic potency. The efficacy of 2H4M as an effective chemosensitizer to monoterpenoid phenols (viz., 2H4M + carvacrol or thymol) was assessed in yeasts or filamentous fungi (Aspergillus, Penicillium) according to European Committee on Antimicrobial Susceptibility Testing or Clinical Laboratory Standards Institute M38-A protocols, respectively. Synergistic chemosensitization greatly lowers minimum inhibitory or fungicidal concentrations of the co-administered compounds. 2H4M also overcame the tolerance of two MAPK mutants (sakAΔ, mpkCΔ) of Aspergillus fumigatus to fludioxonil (phenylpyrrole fungicide). Collectively, 2H4M possesses chemosensitizing capability to magnify the efficacy of monoterpenoid phenols, which improves target-based (viz., cell wall disruption) antifungal intervention.
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Hershkovitz V, Sela N, Taha-Salaime L, Liu J, Rafael G, Kessler C, Aly R, Levy M, Wisniewski M, Droby S. De-novo assembly and characterization of the transcriptome of Metschnikowia fructicola reveals differences in gene expression following interaction with Penicillium digitatum and grapefruit peel. BMC Genomics 2013; 14:168. [PMID: 23496978 PMCID: PMC3608080 DOI: 10.1186/1471-2164-14-168] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 02/25/2013] [Indexed: 11/11/2022] Open
Abstract
Background The yeast Metschnikowia fructicola is an antagonist with biological control activity against postharvest diseases of several fruits. We performed a transcriptome analysis, using RNA-Seq technology, to examine the response of M. fructicola with citrus fruit and with the postharvest pathogen, Penicillium digitatum. Results More than 26 million sequencing reads were assembled into 9,674 unigenes. Approximately 50% of the unigenes could be annotated based on homology matches in the NCBI database. Based on homology, sequences were annotated with a gene description, gene ontology (GO term), and clustered into functional groups. An analysis of differential expression when the yeast was interacting with the fruit vs. the pathogen revealed more than 250 genes with specific expression responses. In the antagonist-pathogen interaction, genes related to transmembrane, multidrug transport and to amino acid metabolism were induced. In the antagonist-fruit interaction, expression of genes involved in oxidative stress, iron homeostasis, zinc homeostasis, and lipid metabolism were induced. Patterns of gene expression in the two interactions were examined at the individual transcript level by quantitative real-time PCR analysis (RT-qPCR). Conclusion This study provides new insight into the biology of the tritrophic interactions that occur in a biocontrol system such as the use of the yeast, M. fructicola for the control of green mold on citrus caused by P. digitatum.
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Affiliation(s)
- Vera Hershkovitz
- Department of Postharvest and Food Sciences, ARO, the Volcani Center, Bet Dagan, 50250, Israel
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Ahmad A, Khan A, Manzoor N. Reversal of efflux mediated antifungal resistance underlies synergistic activity of two monoterpenes with fluconazole. Eur J Pharm Sci 2013; 48:80-6. [DOI: 10.1016/j.ejps.2012.09.016] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 08/04/2012] [Accepted: 09/25/2012] [Indexed: 01/18/2023]
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Key cytomembrane ABC transporters of Saccharomyces cerevisiae fail to improve the tolerance to d-limonene. Biotechnol Lett 2012; 34:1505-9. [DOI: 10.1007/s10529-012-0931-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 04/04/2012] [Indexed: 10/28/2022]
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Zhang Y, Muend S, Rao R. Dysregulation of ion homeostasis by antifungal agents. Front Microbiol 2012; 3:133. [PMID: 22493595 PMCID: PMC3319912 DOI: 10.3389/fmicb.2012.00133] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 03/20/2012] [Indexed: 11/17/2022] Open
Abstract
Ion-signaling and transduction networks are central to fungal development and virulence because they regulate gene expression, filamentation, host association, and invasion, pathogen stress response and survival. Dysregulation of ion homeostasis rapidly mediates cell death, forming the mechanistic basis by which a growing number of amphipathic but structurally unrelated compounds elicit antifungal activity. Included in this group is carvacrol, a terpenoid phenol that is a prominent component of oregano and other plant essential oils. Carvacrol triggers an early dose-dependent Ca2+ burst and long lasting pH changes in the model yeast Saccharomyces cerevisiae. The distinct phases of ionic transients and a robust transcriptional response that overlaps with Ca2+ stress and nutrient starvation point to specific signaling events elicited by plant terpenoid phenols, rather than a non-specific lesion of the membrane, as was previously considered. We discuss the potential use of plant essential oils and other agents that disrupt ion-signaling pathways as chemosensitizers to augment conventional antifungal therapy, and to convert fungistatic drugs with strong safety profiles into fungicides.
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Affiliation(s)
- Yongqiang Zhang
- Department of Physiology, The Johns Hopkins University School of Medicine Baltimore, MD, USA
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Kim JH, Chan KL, Faria NCG, Martins MDL, Campbell BC. Targeting the oxidative stress response system of fungi with redox-potent chemosensitizing agents. Front Microbiol 2012; 3:88. [PMID: 22438852 PMCID: PMC3305922 DOI: 10.3389/fmicb.2012.00088] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 02/22/2012] [Indexed: 11/28/2022] Open
Abstract
The cellular antioxidant system is a target in the antifungal action of amphotericin B (AMB) and itraconazole (ITZ), in filamentous fungi. The sakAΔ mutant of Aspergillus fumigatus, a mitogen-activated protein kinase (MAPK) gene deletion mutant in the antioxidant system, was found to be more sensitive to AMB or ITZ than other A. fumigatus strains, a wild type and a mpkCΔ mutant (a MAPK gene deletion mutant in the polyalcohol sugar utilization system). Complete fungal kill (≥99.9%) by ITZ or AMB was also achieved by much lower dosages for the sakAΔ mutant than for the other strains. It appears msnA, an Aspergillus ortholog to Saccharomyces cerevisiaeMSN2 (encoding a stress-responsive C2H2-type zinc-finger regulator) and sakA and/or mpkC (upstream MAPKs) are in the same stress response network under tert-butyl hydroperoxide (t-BuOOH)-, hydrogen peroxide (H2O2)- or AMB-triggered toxicity. Of note is that ITZ-sensitive yeast pathogens were also sensitive to t-BuOOH, showing a connection between ITZ sensitivity and antioxidant capacity of fungi. Enhanced antifungal activity of AMB or ITZ was achieved when these drugs were co-applied with redox-potent natural compounds, 2,3-dihydroxybenzaldehyde, thymol or salicylaldehyde, as chemosensitizing agents. We concluded that redox-potent compounds, which target the antioxidant system in fungi, possess a chemosensitizing capacity to enhance efficacy of conventional drugs.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
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Campbell BC, Chan KL, Kim JH. Chemosensitization as a means to augment commercial antifungal agents. Front Microbiol 2012; 3:79. [PMID: 22393330 PMCID: PMC3289909 DOI: 10.3389/fmicb.2012.00079] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 02/15/2012] [Indexed: 11/13/2022] Open
Abstract
Antimycotic chemosensitization and its mode of action are of growing interest. Currently, use of antifungal agents in agriculture and medicine has a number of obstacles. Foremost of these is development of resistance or cross-resistance to one or more antifungal agents. The generally high expense and negative impact, or side effects, associated with antifungal agents are two further issues of concern. Collectively, these problems are exacerbated by efforts to control resistant strains, which can evolve into a treadmill of higher dosages for longer periods. This cycle in turn, inflates cost of treatment, dramatically. A further problem is stagnation in development of new and effective antifungal agents, especially for treatment of human mycoses. Efforts to overcome some of these issues have involved using combinations of available antimycotics (e.g., combination therapy for invasive mycoses). However, this approach has had inconsistent success and is often associated with a marked increase in negative side effects. Chemosensitization by natural compounds to increase effectiveness of commercial antimycotics is a somewhat new approach to dealing with the aforementioned problems. The potential for safe natural products to improve antifungal activity has been observed for over three decades. Chemosensitizing agents possess antifungal activity, but at insufficient levels to serve as antimycotics, alone. Their main function is to disrupt fungal stress response, destabilize the structural integrity of cellular and vacuolar membranes or stimulate production of reactive oxygen species, augmenting oxidative stress and apoptosis. Use of safe chemosensitizing agents has potential benefit to both agriculture and medicine. When co-applied with a commercial antifungal agent, an additive or synergistic interaction may occur, augmenting antifungal efficacy. This augmentation, in turn, lowers effective dosages, costs, negative side effects and, in some cases, countermands resistance.
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Affiliation(s)
- Bruce C. Campbell
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
| | - Kathleen L. Chan
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
| | - Jong H. Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of AgricultureAlbany, CA, USA
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Mechanism of antifungal activity of terpenoid phenols resembles calcium stress and inhibition of the TOR pathway. Antimicrob Agents Chemother 2010; 54:5062-9. [PMID: 20921304 DOI: 10.1128/aac.01050-10] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Terpenoid phenols, including carvacrol, are components of oregano and other plant essential oils that exhibit potent antifungal activity against a wide range of pathogens, including Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa. To gain a mechanistic view of the cellular response to terpenoid phenols, we used Saccharomyces cerevisiae as a model organism and monitored temporal changes in metabolic activity, cytosolic and vacuolar pH, and Ca(2+) transients. Using a panel of related compounds, we observed dose-dependent Ca(2+) bursts that correlated with antifungal efficacy. Changes in pH were long lasting and followed the Ca(2+) transients. A vma mutant lacking functional vacuolar H(+)-ATPase (V-ATPase) and defective in ion homeostasis was hypersensitive to carvacrol toxicity, consistent with a role for ionic disruptions in mediating cell death. Genomic profiling within 15 min of exposure revealed a robust transcriptional response to carvacrol, closely resembling that of calcium stress. Genes involved in alternate metabolic and energy pathways, stress response, autophagy, and drug efflux were prominently upregulated, whereas repressed genes mediated ribosome biogenesis and RNA metabolism. These responses were strongly reminiscent of the effects of rapamycin, the inhibitor of the TOR pathway of nutrient sensing. The results point to the activation of specific signaling pathways downstream of cellular interaction with carvacrol rather than a nonspecific lesion of membranes, as has been previously proposed.
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Qiu J, Wang D, Xiang H, Feng H, Jiang Y, Xia L, Dong J, Lu J, Yu L, Deng X. Subinhibitory concentrations of thymol reduce enterotoxins A and B and alpha-hemolysin production in Staphylococcus aureus isolates. PLoS One 2010; 5:e9736. [PMID: 20305813 PMCID: PMC2840024 DOI: 10.1371/journal.pone.0009736] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 02/20/2010] [Indexed: 11/25/2022] Open
Abstract
Background Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., α-hemolysin and enterotoxins) by S. aureus. Methodology/Principal Findings Secretion of α-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF) release assays were performed to elucidate the biological relevance of changes in α-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding α-hemolysin, SEA and SEB, respectively) was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of α-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. Conclusions/Significance Subinhibitory concentrations of thymol decreased the production of α-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with β-lactams and glycopeptide antibiotics, which induce expression of α-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors.
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Affiliation(s)
- Jiazhang Qiu
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Dacheng Wang
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Hua Xiang
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Haihua Feng
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Youshuai Jiang
- College of Life Science and Technology, Heilongjiang August First Agricultural University, Daqing Heilongjiang, People's Republic of China
| | - Lijie Xia
- College of Veterinary Medicine, Yangzhou University, Yangzhou Jiangsu, People's Republic of China
| | - Jing Dong
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Jing Lu
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
| | - Lu Yu
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
- * E-mail: (LY); (XD)
| | - Xuming Deng
- Institute of Zoonoses, College of Animal Sciences and Veterinary Medicine, Jilin University, Changchun Jilin, People's Republic of China
- * E-mail: (LY); (XD)
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