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Benyamin MS, Perisin MP, Hellman CA, Schwalm ND, Jahnke JP, Sund CJ. Modeling control and transduction of electrochemical gradients in acid-stressed bacteria. iScience 2023; 26:107140. [PMID: 37404371 PMCID: PMC10316662 DOI: 10.1016/j.isci.2023.107140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 03/05/2023] [Accepted: 06/12/2023] [Indexed: 07/06/2023] Open
Abstract
Transmembrane electrochemical gradients drive solute uptake and constitute a substantial fraction of the cellular energy pool in bacteria. These gradients act not only as "homeostatic contributors," but also play a dynamic and keystone role in several bacterial functions, including sensing, stress response, and metabolism. At the system level, multiple gradients interact with ion transporters and bacterial behavior in a complex, rapid, and emergent manner; consequently, experiments alone cannot untangle their interdependencies. Electrochemical gradient modeling provides a general framework to understand these interactions and their underlying mechanisms. We quantify the generation, maintenance, and interactions of electrical, proton, and potassium potential gradients under lactic acid-stress and lactic acid fermentation. Further, we elucidate a gradient-mediated mechanism for intracellular pH sensing and stress response. We demonstrate that this gradient model can yield insights on the energetic limitations of membrane transport, and can predict bacterial behavior across changing environments.
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Affiliation(s)
- Marcus S. Benyamin
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
| | - Matthew P. Perisin
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
| | - Caleb A. Hellman
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
| | - Nathan D. Schwalm
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
| | - Justin P. Jahnke
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
| | - Christian J. Sund
- Biological and Biotechnology Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA
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2
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Fitzgerald BA, Wadud A, Slimak Z, Slonczewski JL. Enterococcus faecalis OG1RF Evolution at Low pH Selects Fusidate-Sensitive Mutants in Elongation Factor G and at High pH Selects Defects in Phosphate Transport. Appl Environ Microbiol 2023; 89:e0046623. [PMID: 37272807 PMCID: PMC10304957 DOI: 10.1128/aem.00466-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/15/2023] [Indexed: 06/06/2023] Open
Abstract
Enterococcus bacteria inhabit human and soil environments that show a wide range of pH values. Strains include commensals as well as antibiotic-resistant pathogens. We investigated the adaptation to pH stress in E. faecalis OG1RF by conducting experimental evolution under acidic (pH 4.8), neutral pH (pH 7.0), and basic (pH 9.0) conditions. A serial planktonic culture was performed for 500 generations and in a high-pH biofilm culture for 4 serial bead transfers. Nearly all of the mutations led to nonsynonomous codons, indicating adaptive selection. All of the acid-adapted clones from the planktonic culture showed a mutation in fusA (encoding elongation factor G). The acid-adapted fusA mutants had a trade-off of decreased resistance to fusidic acid (fusidate). All of the base-adapted clones from the planktonic cultures as well as some from the biofilm-adapted cultures showed mutations that affected the Pst phosphate ABC transporter (pstA, pstB, pstB2, pstC) and pyrR (pyrimidine biosynthesis regulator/uracil phosphoribosyltransferase). The biofilm cultures produced small-size colonies on brain heart infusion agar. These variants each contained a single mutation in pstB2, pstC, or pyrR. The pst and pyrR mutants outgrew the ancestral strain at pH 9.2, with a trade-off of lower growth at pH 4.8. Additional genes that had a mutation in multiple clones that evolved at high pH (but not at low pH) include opp1BCDF (oligopeptide ABC transporter), ccpA (catabolite control protein A), and ftsZ (septation protein). Overall, the experimental evolution of E. faecalis showed a strong pH dependence, favoring the fusidate-sensitive elongation factor G modification at low pH and the loss of phosphate transport genes at high pH. IMPORTANCE E. faecalis bacteria are found in dental biofilms, where they experience low pH as a result of fermentative metabolism. Thus, the effect of pH on antibiotic resistance has clinical importance. The loss of fusidate resistance is notable for OG1RF strains in which fusidate resistance is assumed to be a stable genetic marker. In endodontal infections, enterococci can resist calcium hydroxide therapy that generates extremely high pH values. In other environments, such as the soil and plant rhizosphere, enterococci experience acidification that is associated with climate change. Thus, the pH modulation of natural selection in enterococci is important for human health as well as for understanding soil environments.
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Affiliation(s)
| | - Ayman Wadud
- Department of Biology, Kenyon College, Gambier, Ohio, USA
| | - Zachary Slimak
- Department of Biology, Kenyon College, Gambier, Ohio, USA
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3
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Acciarri G, Gizzi FO, Torres Manno MA, Stülke J, Espariz M, Blancato VS, Magni C. Redundant potassium transporter systems guarantee the survival of Enterococcus faecalis under stress conditions. Front Microbiol 2023; 14:1117684. [PMID: 36846772 PMCID: PMC9945522 DOI: 10.3389/fmicb.2023.1117684] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/17/2023] [Indexed: 02/10/2023] Open
Abstract
Enterococcus is able to grow in media at pH from 5.0 to 9.0 and a high concentration of NaCl (8%). The ability to respond to these extreme conditions requires the rapid movement of three critical ions: proton (H+), sodium (Na+), and potassium (K+). The activity of the proton F0F1 ATPase and the sodium Na+ V0V1 type ATPase under acidic or alkaline conditions, respectively, is well established in these microorganisms. The potassium uptake transporters KtrI and KtrII were described in Enterococcus hirae, which were associated with growth in acidic and alkaline conditions, respectively. In Enterococcus faecalis, the presence of the Kdp (potassium ATPase) system was early established. However, the homeostasis of potassium in this microorganism is not completely explored. In this study, we demonstrate that Kup and KimA are high-affinity potassium transporters, and the inactivation of these genes in E. faecalis JH2-2 (a Kdp laboratory natural deficient strain) had no effect on the growth parameters. However, in KtrA defective strains (ΔktrA, ΔkupΔktrA) an impaired growth was observed under stress conditions, which was restored to wild type levels by external addition of K+ ions. Among the multiplicity of potassium transporters identify in the genus Enterococcus, Ktr channels (KtrAB and KtrAD), and Kup family symporters (Kup and KimA) are present and may contribute to the particular resistance of these microorganisms to different stress conditions. In addition, we found that the presence of the Kdp system in E. faecalis is strain-dependent, and this transporter is enriched in strains of clinical origin as compared to environmental, commensal, or food isolates.
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Affiliation(s)
- Giuliana Acciarri
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina
| | - Fernán O. Gizzi
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina
| | - Mariano A. Torres Manno
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina,Área Bioinformática, Departamento de Matemática y Estadística, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Jörg Stülke
- Department of General Microbiology, Georg August University, Göttingen, Germany
| | - Martín Espariz
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina,Área Bioinformática, Departamento de Matemática y Estadística, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Víctor S. Blancato
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina,Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos, FBioyF, UNR–Municipalidad de Granadero Baigorria, Rosario, Argentina
| | - Christian Magni
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Rosario, Argentina,Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos, FBioyF, UNR–Municipalidad de Granadero Baigorria, Rosario, Argentina,*Correspondence: Christian Magni, ✉
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Saxena P, Rauniyar S, Thakur P, Singh RN, Bomgni A, Alaba MO, Tripathi AK, Gnimpieba EZ, Lushbough C, Sani RK. Integration of text mining and biological network analysis: Identification of essential genes in sulfate-reducing bacteria. Front Microbiol 2023; 14:1086021. [PMID: 37125195 PMCID: PMC10133479 DOI: 10.3389/fmicb.2023.1086021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/23/2023] [Indexed: 05/02/2023] Open
Abstract
The growth and survival of an organism in a particular environment is highly depends on the certain indispensable genes, termed as essential genes. Sulfate-reducing bacteria (SRB) are obligate anaerobes which thrives on sulfate reduction for its energy requirements. The present study used Oleidesulfovibrio alaskensis G20 (OA G20) as a model SRB to categorize the essential genes based on their key metabolic pathways. Herein, we reported a feedback loop framework for gene of interest discovery, from bio-problem to gene set of interest, leveraging expert annotation with computational prediction. Defined bio-problem was applied to retrieve the genes of SRB from literature databases (PubMed, and PubMed Central) and annotated them to the genome of OA G20. Retrieved gene list was further used to enrich protein-protein interaction and was corroborated to the pangenome analysis, to categorize the enriched gene sets and the respective pathways under essential and non-essential. Interestingly, the sat gene (dde_2265) from the sulfur metabolism was the bridging gene between all the enriched pathways. Gene clusters involved in essential pathways were linked with the genes from seleno-compound metabolism, amino acid metabolism, secondary metabolite synthesis, and cofactor biosynthesis. Furthermore, pangenome analysis demonstrated the gene distribution, where 69.83% of the 116 enriched genes were mapped under "persistent," inferring the essentiality of these genes. Likewise, 21.55% of the enriched genes, which involves specially the formate dehydrogenases and metallic hydrogenases, appeared under "shell." Our methodology suggested that semi-automated text mining and network analysis may play a crucial role in deciphering the previously unexplored genes and key mechanisms which can help to generate a baseline prior to perform any experimental studies.
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Affiliation(s)
- Priya Saxena
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Shailabh Rauniyar
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Payal Thakur
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Ram Nageena Singh
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Alain Bomgni
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Mathew O. Alaba
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Abhilash Kumar Tripathi
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Etienne Z. Gnimpieba
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
- *Correspondence: Etienne Z. Gnimpieba,
| | - Carol Lushbough
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Rajesh Kumar Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Rajesh Kumar Sani,
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5
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Li G, Zheng X, Zhu Y, Long Y, Xia X. In-depth insights into the disruption of the microbiota-gut-blood barrier of model organism (Bombyx mori) by fluoride. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156220. [PMID: 35623528 DOI: 10.1016/j.scitotenv.2022.156220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
Fluoride is a serious health risk to animals and humans. The microbiota-gut-blood barrier (MGBB) plays an indispensable role in maintaining the systematic homeostasis of host organisms. However, the toxic effects of fluoride on MGBB of organisms have not been extensively investigated. Here, we used the silkworm interspecies model to explore the adverse effects of fluoride on the gut microbiota and intestinal tissue and circulating metabolites of organisms. Results showed that fluoride exposure significantly declined the body weight gain and survival rate of organisms and evidently damaged intestinal epithelial cells. In addition, fluoride altered the composition and abundance of intestinal microbiota, which was accompanied by changing gene expression levels of antimicrobial peptides in intestinal tissue. Shifts in the relative abundance of Enterococcus, Aquabacterium, Aureimonas and Methylobacterium in the gut had significant correlations with the concentrations of certain differential metabolites (e.g., amino acids, nucleotides, and nucleotide derivatives) in the bloodstream. Moreover, most circulating metabolites in related nucleotide metabolism pathways were upregulated, whereas those in the pathways of amino acid metabolism were downregulated. This study deepens our understanding of the disruptive effect of fluoride on the MGBB of host organisms and may provide a new insight into the preventive therapy of fluoride-induced diseases.
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Affiliation(s)
- Guannan Li
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing 400716, China
| | - Xi Zheng
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing 400716, China
| | - Yong Zhu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass, Southwest University, Chongqing 400716, China
| | - Yaohang Long
- Key Laboratory of Biology and Medical Engineering, Immune Cells and Antibody Engineering Research Center of Guizhou Province, School of Biology and Engineering, Guizhou Medical University, Guiyang 550025, Guizhou Province, China; Engineering Research Center of Medical Biotechnology, Guizhou Medical University, Guiyang 550025, Guizhou Province, China.
| | - Xuejuan Xia
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
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Deng JJ, Deng D, Wang ZL, Luo XC, Chen HP, Liu SY, Ma XY, Li JZ. Indole metabolism mechanisms in a new, efficient indole-degrading facultative anaerobe isolate Enterococcus hirae GDIAS-5. JOURNAL OF HAZARDOUS MATERIALS 2022; 434:128890. [PMID: 35452978 DOI: 10.1016/j.jhazmat.2022.128890] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/04/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Indole is an inter-species and inter-kingdom signaling molecule widespread in the natural world. A large amount of indole in livestock wastes makes it difficult to be degraded, which causes serious malodor. Identifying efficient and eco-friendly ways to eliminate it is an urgent task for the sustainable development of husbandry. While bioconversion is a widely accepted means, the mechanism of indole microbial degradation is little understood, especially under anaerobic conditions. Herein, a new Enterococcus hirae isolate GDIAS-5, effectively degraded 100 mg/L indole within 28 h aerobically or 5 days anaerobically. Three intermediates (oxindole, isatin, and catechol) were identified in indole degradation, and catechol was further degraded by a meta-cleavage catabolic pathway. Two important processes for GDIAS-5 indole utilization were discovered. One is Fe(III) uptake and reduction, which may be a critical process that is coupled with indole oxidation, and the other is the entire pathway directly involved in indole oxidation and metabolism. Furthermore, monooxygenase ycnE responsible for indole oxidation via the indole-oxindole-isatin pathway was identified for the first time. Bioinformatic analyses showed that ycnE from E. hirae formed a phylogenetically separate branch from monooxygenases of other species. These findings provide new targets and strategies for synthetic biological reconstruction of indole-degrading bacteria.
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Affiliation(s)
- Jun-Jin Deng
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, The Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding and Nutrition, No. 1 Dafeng Street, Wushan Road, Tianhe District, Guangzhou, Guangdong 510640, China
| | - Dun Deng
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, The Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding and Nutrition, No. 1 Dafeng Street, Wushan Road, Tianhe District, Guangzhou, Guangdong 510640, China
| | - Zhi-Lin Wang
- Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Xiao-Chun Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Panyu District, Guangzhou, Guangdong 510006, China
| | - Hong-Ping Chen
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, The Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding and Nutrition, No. 1 Dafeng Street, Wushan Road, Tianhe District, Guangzhou, Guangdong 510640, China
| | - Shu-Yang Liu
- School of Life Sciences and Engineering, Foshan University, Foshan, Guangdong 528225, China
| | - Xian-Yong Ma
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, The Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding and Nutrition, No. 1 Dafeng Street, Wushan Road, Tianhe District, Guangzhou, Guangdong 510640, China
| | - Jia-Zhou Li
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, The Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding and Nutrition, No. 1 Dafeng Street, Wushan Road, Tianhe District, Guangzhou, Guangdong 510640, China.
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7
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Braga LPP, Pereira RV, Martins LF, Moura LMS, Sanchez FB, Patané JSL, da Silva AM, Setubal JC. Genome-resolved metagenome and metatranscriptome analyses of thermophilic composting reveal key bacterial players and their metabolic interactions. BMC Genomics 2021; 22:652. [PMID: 34507539 PMCID: PMC8434746 DOI: 10.1186/s12864-021-07957-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/23/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Composting is an important technique for environment-friendly degradation of organic material, and is a microbe-driven process. Previous metagenomic studies of composting have presented a general description of the taxonomic and functional diversity of its microbial populations, but they have lacked more specific information on the key organisms that are active during the process. RESULTS Here we present and analyze 60 mostly high-quality metagenome-assembled genomes (MAGs) recovered from time-series samples of two thermophilic composting cells, of which 47 are potentially new bacterial species; 24 of those did not have any hits in two public MAG datasets at the 95% average nucleotide identity level. Analyses of gene content and expressed functions based on metatranscriptome data for one of the cells grouped the MAGs in three clusters along the 99-day composting process. By applying metabolic modeling methods, we were able to predict metabolic dependencies between MAGs. These models indicate the importance of coadjuvant bacteria that do not carry out lignocellulose degradation but may contribute to the management of reactive oxygen species and with enzymes that increase bioenergetic efficiency in composting, such as hydrogenases and N2O reductase. Strong metabolic dependencies predicted between MAGs revealed key interactions relying on exchange of H+, NH3, O2 and CO2, as well as glucose, glutamate, succinate, fumarate and others, highlighting the importance of functional stratification and syntrophic interactions during biomass conversion. Our model includes 22 out of 49 MAGs recovered from one composting cell data. Based on this model we highlight that Rhodothermus marinus, Thermobispora bispora and a novel Gammaproteobacterium are dominant players in chemolithotrophic metabolism and cross-feeding interactions. CONCLUSIONS The results obtained expand our knowledge of the taxonomic and functional diversity of composting bacteria and provide a model of their dynamic metabolic interactions.
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Affiliation(s)
- Lucas Palma Perez Braga
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Layla Farage Martins
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Livia Maria Silva Moura
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Bioinformática, Universidade de São Paulo, São Paulo, Brazil
| | - Fabio Beltrame Sanchez
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Bioinformática, Universidade de São Paulo, São Paulo, Brazil
| | | | - Aline Maria da Silva
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
| | - João Carlos Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
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Jia S, Hong H, Yang Q, Liu X, Zhuang S, Li Y, Liu J, Luo Y. TMT-based proteomic analysis of the fish-borne spoiler Pseudomonas psychrophila subjected to chitosan oligosaccharides in fish juice system. Food Microbiol 2020; 90:103494. [DOI: 10.1016/j.fm.2020.103494] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/04/2020] [Accepted: 03/17/2020] [Indexed: 01/16/2023]
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9
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Ahn SJ, Desai S, Blanco L, Lin M, Rice KC. Acetate and Potassium Modulate the Stationary-Phase Activation of lrgAB in Streptococcus mutans. Front Microbiol 2020; 11:401. [PMID: 32231651 PMCID: PMC7082836 DOI: 10.3389/fmicb.2020.00401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/26/2020] [Indexed: 12/28/2022] Open
Abstract
Fluctuating environments force bacteria to constantly adapt and optimize the uptake of substrates to maintain cellular and nutritional homeostasis. Our recent findings revealed that LrgAB functions as a pyruvate uptake system in Streptococcus mutans, and its activity is modulated in response to glucose and oxygen levels. Here, we show that the composition of the growth medium dramatically influences the magnitude and pattern of lrgAB activation. Specifically, tryptone (T) medium does not provide a preferred environment for stationary phase lrgAB activation, which is independent of external pyruvate concentration. The addition of pyruvate to T medium can elicit PlrgA activation during exponential growth, enabling the cell to utilize external pyruvate for improvement of cell growth. Through comparison of the medium composition and a series of GFP quantification assays for measurement of PlrgA activation, we found that acetate and potassium (K+) play important roles in eliciting PlrgA activation at stationary phase. Of note, supplementation of pooled human saliva to T medium induced lrgAB expression at stationary phase and in response to pyruvate, suggesting that LrgAB is likely functional in the oral cavity. High concentrations of acetate inhibit cell growth, while high concentrations of K+ negatively regulate lrgAB activation. qPCR analysis also revealed that growth in T medium (acetate/K+ limited) significantly affects the expression of genes related to the catabolic pathways of pyruvate, including the Pta/AckA pathway (acetate metabolism). Lastly, stationary phase lrgAB expression is not activated when S. mutans is cultured in T medium, even in a strain that overexpresses lytST. Taken together, these data suggest that lrgAB activation and pyruvate uptake in S. mutans are connected to acetate metabolism and potassium uptake systems, important for cellular and energy homeostasis. They also suggest that these factors need to be implemented when planning metabolic experiments and analyzing data in S. mutans studies that may be sensitive to stationary growth phase.
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Affiliation(s)
- Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Shailja Desai
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Loraine Blanco
- Department of Biology, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, United States
| | - Min Lin
- Department of Chemistry, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, United States
| | - Kelly C Rice
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
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Anaerobic reduction of europium by a Clostridium strain as a strategy for rare earth biorecovery. Sci Rep 2019; 9:14339. [PMID: 31586093 PMCID: PMC6778152 DOI: 10.1038/s41598-019-50179-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 07/25/2019] [Indexed: 11/13/2022] Open
Abstract
The biorecovery of europium (Eu) from primary (mineral deposits) and secondary (mining wastes) resources is of interest due to its remarkable luminescence properties, important for modern technological applications. In this study, we explored the tolerance levels, reduction and intracellular bioaccumulation of Eu by a site-specific bacterium, Clostridium sp. 2611 isolated from Phalaborwa carbonatite complex. Clostridium sp. 2611 was able to grow in minimal medium containing 0.5 mM Eu3+. SEM-EDX analysis confirmed an association between Eu precipitates and the bacterium, while TEM-EDX analysis indicated intracellular accumulation of Eu. According to the HR-XPS analysis, the bacterium was able to reduce Eu3+ to Eu2+ under growth and non-growth conditions. Preliminary protein characterization seems to indicate that a cytoplasmic pyruvate oxidoreductase is responsible for Eu bioreduction. These findings suggest the bioreduction of Eu3+ by Clostridium sp. as a resistance mechanism, can be exploited for the biorecovery of this metal.
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11
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Mehta S, Verma P, Tikku AP, Chandra A, Bains R, Banerjee G. Comparative evaluation of antimicrobial efficacy of triple antibiotic paste, calcium hydroxide, and a proton pump inhibitor against resistant root canal pathogens. Eur J Dent 2019; 11:53-57. [PMID: 28435366 PMCID: PMC5379835 DOI: 10.4103/ejd.ejd_159_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Objective: The objective of this study is to compare the antimicrobial efficacy of triple antibiotic paste (TAP) and a proton pump inhibitor (PPI) (omeprazole) in combination with calcium hydroxide (CH) against Enterococcus faecalis and Candida albicans. Materials and Methods: E. faecalis and C. albicans were subcultured and inoculated at 37° overnight and were treated with different dilutions of TAP, 25 μg/ml (Group 1), CH (Group 2, control), CH 16 mg/ml + omeprazole 2 mg/ml (Group 3a) (CH 16 mg/ml + omeprazole 4 mg)/ml (Group 3b) for 24, 48, and 72 h in sterile uncoated 96-well microtiter plates. Minimum concentration at which the medicaments produced least optical density was determined using ELISA reader (ELx 808 BioTek Inc., USA) device set at optical density of 630 nm. Results were analyzed statistically by one-way analysis of variance followed by Tukey's multiple comparison tests. The significance level was set at 0.05. Results: Mean concentration (irrespective of time) for TAP at which mean minimum optical density was recorded at 1.25 μg/ml (1:20 dilution) and 25 μg/ml (0 dilution) against E. faecalis and C. albicans, respectively. Least optical density for CH plus PPI group was obtained 1.6 μg/ml (1:10 dilution) and 16 μg/ml (0 dilution) for E. faecalis and C. albicans, respectively. However, CH alone showed a weaker antimicrobial action against either of the strains even at full concentration. Conclusions: PPI enhanced the antibacterial efficacy of CH against E. faecalis and C. albicans. However, TAP showed the best antibacterial property followed by CH plus PPIs against both the selected strains.
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Affiliation(s)
- Shibha Mehta
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Promila Verma
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Aseem Prakash Tikku
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Anil Chandra
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Rhythm Bains
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Gopa Banerjee
- Department of Microbiology, King George's Medical University, Lucknow, Uttar Pradesh, India
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12
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Ben Braïek O, Smaoui S. Enterococci: Between Emerging Pathogens and Potential Probiotics. BIOMED RESEARCH INTERNATIONAL 2019; 2019:5938210. [PMID: 31240218 PMCID: PMC6556247 DOI: 10.1155/2019/5938210] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/06/2019] [Accepted: 05/14/2019] [Indexed: 11/17/2022]
Abstract
Enterococci are ubiquitous microorganisms that could be found everywhere; in water, plant, soil, foods, and gastrointestinal tract of humans and animals. They were previously used as starters in food fermentation due to their biotechnological traits (enzymatic and proteolytic activities) or protective cultures in food biopreservation due to their produced antimicrobial bacteriocins called enterocins or as probiotics, live cells with different beneficial characteristics such as stimulation of immunity, anti-inflammatory activity, hypocholesterolemic effect, and prevention/treatment of some diseases. However, in the last years, the use of enterococci in foods or as probiotics caused an important debate because of their opportunistic pathogenicity implicated in several nosocomial infections due to virulence factors and antibiotic resistance, particularly the emergence of vancomycin-resistant enterococci. These virulence traits of some enterococci are associated with genetic transfer mechanisms. Therefore, the development of new enterococcal probiotics needs a strict assessment with regard to safety aspects for selecting the truly harmless enterococcal strains for safe applications. This review tries to give some data of the different points of view about this question.
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Affiliation(s)
- Olfa Ben Braïek
- Laboratory of Transmissible Diseases and Biologically Active Substances (LR99ES27), Faculty of Pharmacy, University of Monastir, Tunisia
| | - Slim Smaoui
- Laboratory of Microorganisms and Biomolecules of the Centre of Biotechnology of Sfax, Tunisia
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13
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Impaired oxidative stress and sulfur assimilation contribute to acid tolerance of Corynebacterium glutamicum. Appl Microbiol Biotechnol 2019; 103:1877-1891. [DOI: 10.1007/s00253-018-09585-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 10/27/2022]
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14
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Tan Z, Khakbaz P, Chen Y, Lombardo J, Yoon JM, Shanks JV, Klauda JB, Jarboe LR. Engineering Escherichia coli membrane phospholipid head distribution improves tolerance and production of biorenewables. Metab Eng 2017; 44:1-12. [DOI: 10.1016/j.ymben.2017.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 08/26/2017] [Accepted: 08/29/2017] [Indexed: 12/27/2022]
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15
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Shabayek S, Spellerberg B. Acid Stress Response Mechanisms of Group B Streptococci. Front Cell Infect Microbiol 2017; 7:395. [PMID: 28936424 PMCID: PMC5594096 DOI: 10.3389/fcimb.2017.00395] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 08/23/2017] [Indexed: 12/20/2022] Open
Abstract
Group B streptococcus (GBS) is a leading cause of neonatal mortality and morbidity in the United States and Europe. It is part of the vaginal microbiota in up to 30% of pregnant women and can be passed on to the newborn through perinatal transmission. GBS has the ability to survive in multiple different host niches. The pathophysiology of this bacterium reveals an outstanding ability to withstand varying pH fluctuations of the surrounding environments inside the human host. GBS host pathogen interations include colonization of the acidic vaginal mucosa, invasion of the neutral human blood or amniotic fluid, breaching of the blood brain barrier as well as survival within the acidic phagolysosomal compartment of macrophages. However, investigations on GBS responses to acid stress are limited. Technologies, such as whole genome sequencing, genome-wide transcription and proteome mapping facilitate large scale identification of genes and proteins. Mechanisms enabling GBS to cope with acid stress have mainly been studied through these techniques and are summarized in the current review
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Affiliation(s)
- Sarah Shabayek
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany.,Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal UniversityIsmailia, Egypt
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany
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16
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Abachi S, Lee S, Rupasinghe HPV. Molecular Mechanisms of Inhibition of Streptococcus Species by Phytochemicals. Molecules 2016; 21:E215. [PMID: 26901172 PMCID: PMC6273676 DOI: 10.3390/molecules21020215] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/04/2016] [Accepted: 02/06/2016] [Indexed: 12/11/2022] Open
Abstract
This review paper summarizes the antibacterial effects of phytochemicals of various medicinal plants against pathogenic and cariogenic streptococcal species. The information suggests that these phytochemicals have potential as alternatives to the classical antibiotics currently used for the treatment of streptococcal infections. The phytochemicals demonstrate direct bactericidal or bacteriostatic effects, such as: (i) prevention of bacterial adherence to mucosal surfaces of the pharynx, skin, and teeth surface; (ii) inhibition of glycolytic enzymes and pH drop; (iii) reduction of biofilm and plaque formation; and (iv) cell surface hydrophobicity. Collectively, findings from numerous studies suggest that phytochemicals could be used as drugs for elimination of infections with minimal side effects.
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Affiliation(s)
- Soheila Abachi
- Faculty of Agriculture, Dalhousie University, Truro, NS PO Box 550, Canada.
| | - Song Lee
- Faculty of Dentistry, Dalhousie University, Halifax, NS PO Box 15000, Canada.
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17
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Vardanyan Z, Gevorkyan V, Ananyan M, Vardapetyan H, Trchounian A. Effects of various heavy metal nanoparticles on Enterococcus hirae and Escherichia coli growth and proton-coupled membrane transport. J Nanobiotechnology 2015; 13:69. [PMID: 26474562 PMCID: PMC4609144 DOI: 10.1186/s12951-015-0131-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/06/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Due to bacterial resistance to antibiotics there is a need for new antimicrobial agents. In this respect nanoparticles can be used as they have expressed antibacterial activity simultaneously being more reactive compared to their bulk material. The action of zinc (II), titanium (IV), copper (II) and (I) oxides thin films with nanostructured surface and silver nanoscale particles on Enterococcus hirae and Escherichia coli growth and membrane activity was studied by using microbiological, potentiometric and spectrophotometric methods. RESULTS It was revealed that sapphire base plates with deposited ZnO, TiO2, CuO and Cu2O nanoparticles had no effects neither on E. hirae nor E. coli growth both on agar plates and in liquid medium. Concentrated Ag nanoparticles colloid solution markedly affected bacterial growth which was expressed by changing growth properties. E. hirae was able to grow only at <1:200 dilutions of Ag nanoparticles while E. coli grew even at 1:10 dilution. At the same time Ag nanoparticles directly affected membranes, as the FOF1-ATPase activity and H(+)-coupled transport was changed either (E. coli were less susceptible to nanoparticles compared to E. hirae). Ag nanoparticles increased H(+) and K(+) transport even in the presence of N,N'-dicyclohexylcarbodiimide (DCCD), inhibitor of FOF1. The stoichiometry of DCCD-inhibited ion fluxes was disturbed. CONCLUSIONS These results point out to distinguishing antibacterial effects of Ag nanoparticles on different bacteria; the difference between effects can be explained by peculiarities in bacterial membrane structure and properties. H(+)-K(+)-exchange disturbance by Ag nanoparticles might be involved in antibacterial effects on E. hirae. The role of FOF1 in antibacterial action of Ag nanoparticles was shown using atpD mutant lacked β subunit in F1.
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Affiliation(s)
- Zaruhi Vardanyan
- Research Institute of Biology, Faculty of Biology, Yerevan State University, 1 A. Manoukian Str., 0025, Yerevan, Armenia.
| | - Vladimir Gevorkyan
- Department of Materials Technology and Structures of Electronic Technique, Institute of Mathematics and High Technologies, Russian-Armenian (Slavonic) University, 123 H. Emin Str., 0051, Yerevan, Armenia.
| | - Michail Ananyan
- "Nano-industry" Concern, 4 Bardin Str., 1 bulk, 119334, Moscow, Russia.
| | - Hrachik Vardapetyan
- Department of Medicinal Biochemistry and Biotechnology, Institute of Mathematics and High Technologies, Russian-Armenian (Slavonic) University, 123 H. Emin Str., 0051, Yerevan, Armenia.
| | - Armen Trchounian
- Research Institute of Biology, Faculty of Biology, Yerevan State University, 1 A. Manoukian Str., 0025, Yerevan, Armenia.
- Department of Medicinal Biochemistry and Biotechnology, Institute of Mathematics and High Technologies, Russian-Armenian (Slavonic) University, 123 H. Emin Str., 0051, Yerevan, Armenia.
- Department of Microbiology, Microbes and Plants Biotechnology, Faculty of Biology, Yerevan State University, 1 A. Manoukian Str., 0025, Yerevan, Armenia.
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18
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Ran S, Liu B, Jiang W, Sun Z, Liang J. Transcriptome analysis of Enterococcus faecalis in response to alkaline stress. Front Microbiol 2015; 6:795. [PMID: 26300863 PMCID: PMC4528170 DOI: 10.3389/fmicb.2015.00795] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/22/2015] [Indexed: 11/13/2022] Open
Abstract
Enterococcus faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing. We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs) for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections.
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Affiliation(s)
- Shujun Ran
- Shanghai Key Laboratory of Stomatology, Department of Endodontics and Operative Dentistry, School of Medicine, Ninth People's Hospital, Shanghai Jiao Tong University Shanghai, China
| | - Bin Liu
- Shanghai Key Laboratory of Stomatology, Department of Endodontics and Operative Dentistry, School of Medicine, Ninth People's Hospital, Shanghai Jiao Tong University Shanghai, China
| | - Wei Jiang
- Shanghai Key Laboratory of Stomatology, Department of Endodontics and Operative Dentistry, School of Medicine, Ninth People's Hospital, Shanghai Jiao Tong University Shanghai, China
| | - Zhe Sun
- Shanghai Key Laboratory of Stomatology, Department of Endodontics and Operative Dentistry, School of Medicine, Ninth People's Hospital, Shanghai Jiao Tong University Shanghai, China
| | - Jingping Liang
- Shanghai Key Laboratory of Stomatology, Department of Endodontics and Operative Dentistry, School of Medicine, Ninth People's Hospital, Shanghai Jiao Tong University Shanghai, China
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19
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Ran SJ, Jiang W, Zhu CL, Liang JP. Exploration of the mechanisms of biofilm formation byEnterococcus faecalisin glucose starvation environments. Aust Dent J 2015; 60:143-53. [PMID: 25990488 DOI: 10.1111/adj.12324] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2014] [Indexed: 11/26/2022]
Affiliation(s)
- SJ Ran
- Department of Endodontics and Operative Dentistry; Shanghai Key Laboratory of Stomatology; Ninth People's Hospital; School of Medicine; Shanghai Jiao Tong University; Shanghai China
| | - W Jiang
- Department of Endodontics and Operative Dentistry; Shanghai Key Laboratory of Stomatology; Ninth People's Hospital; School of Medicine; Shanghai Jiao Tong University; Shanghai China
| | - CL Zhu
- Shanghai Research Institute of Stomatology; Ninth People's Hospital; School of Medicine; Shanghai Jiao Tong University; Shanghai China
| | - JP Liang
- Department of Endodontics and Operative Dentistry; Shanghai Key Laboratory of Stomatology; Ninth People's Hospital; School of Medicine; Shanghai Jiao Tong University; Shanghai China
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20
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Senouci-Rezkallah K, Jobin MP, Schmitt P. Adaptive responses of Bacillus cereus ATCC14579 cells upon exposure to acid conditions involve ATPase activity to maintain their internal pH. Microbiologyopen 2015; 4:313-322. [PMID: 25740257 PMCID: PMC4398511 DOI: 10.1002/mbo3.239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/17/2014] [Accepted: 12/22/2014] [Indexed: 11/08/2022] Open
Abstract
This study examined the involvement of ATPase activity in the acid tolerance response (ATR) of Bacillus cereus ATCC14579 strain. In the current work, B. cereus cells were grown in anaerobic chemostat culture at external pH (pHe ) 7.0 or 5.5 and at a growth rate of 0.2 h-1 . Population reduction and internal pH (pHi ) after acid shock at pH 4.0 was examined either with or without ATPase inhibitor N,N'-dicyclohexylcarbodiimide (DCCD) and ionophores valinomycin and nigericin. Population reduction after acid shock at pH 4.0 was strongly limited in cells grown at pH 5.5 (acid-adapted cells) compared with cells grown at pH 7.0 (unadapted cells), indicating that B. cereus cells grown at low pHe were able to induce a significant ATR and Exercise-induced increase in ATPase activity. However, DCCD and ionophores had a negative effect on the ability of B. cereus cells to survive and maintain their pHi during acid shock. When acid shock was achieved after DCCD treatment, pHi was markedly dropped in unadapted and acid-adapted cells. The ATPase activity was also significantly inhibited by DCCD and ionophores in acid-adapted cells. Furthermore, transcriptional analysis revealed that atpB (ATP beta chain) transcripts was increased in acid-adapted cells compared to unadapted cells before and after acid shock. Our data demonstrate that B. cereus is able to induce an ATR during growth at low pH. These adaptations depend on the ATPase activity induction and pHi homeostasis. Our data demonstrate that the ATPase enzyme can be implicated in the cytoplasmic pH regulation and in acid tolerance of B. cereus acid-adapted cells.
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Affiliation(s)
- Khadidja Senouci-Rezkallah
- UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université d'Avignon, 84914, Avignon, France.,Faculté des Sciences de la Nature et de la Vie, Université de Mascara, Mascara, Algérie.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Michel P Jobin
- UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université d'Avignon, 84914, Avignon, France
| | - Philippe Schmitt
- UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université d'Avignon, 84914, Avignon, France
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21
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Ali S, Hasan K, Bin Asif H, Abbasi A. Environmental enterococci: I. Prevalence of virulence, antibiotic resistance and species distribution in poultry and its related environment in Karachi, Pakistan. Lett Appl Microbiol 2014. [DOI: 10.1111/lam.12208] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S.A. Ali
- International Center for Chemical and Biological Sciences (ICCBS); HEJ Research Institute of Chemistry; University of Karachi; Karachi Pakistan
| | - K.A. Hasan
- International Center for Chemical and Biological Sciences (ICCBS); HEJ Research Institute of Chemistry; University of Karachi; Karachi Pakistan
| | - H. Bin Asif
- International Center for Chemical and Biological Sciences (ICCBS); HEJ Research Institute of Chemistry; University of Karachi; Karachi Pakistan
| | - A. Abbasi
- International Center for Chemical and Biological Sciences (ICCBS); HEJ Research Institute of Chemistry; University of Karachi; Karachi Pakistan
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22
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Engevik MA, Aihara E, Montrose MH, Shull GE, Hassett DJ, Worrell RT. Loss of NHE3 alters gut microbiota composition and influences Bacteroides thetaiotaomicron growth. Am J Physiol Gastrointest Liver Physiol 2013; 305:G697-711. [PMID: 24072680 PMCID: PMC3840232 DOI: 10.1152/ajpgi.00184.2013] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Changes in the intestinal microbiota have been linked to diabetes, obesity, inflammatory bowel disease, and Clostridium difficile (C. difficile)-associated disease. Despite this, it remains unclear how the intestinal environment, set by ion transport, affects luminal and mucosa-associated bacterial composition. Na(+)/H(+)-exchanger isoform 3 (NHE3), a target of C. difficile toxin B, plays an integral role in intestinal Na(+) absorption. Thus the NHE3-deficient mouse model was chosen to examine the effect of pH and ion composition on bacterial growth. We hypothesized that ion transport-induced change in the intestinal environment would lead to alteration of the microbiota. Region-specific changes in ion composition and pH correlated with region-specific alteration of luminal and mucosal-associated bacteria with general decreases in Firmicutes and increases in Bacteroidetes members. Bacteroides thetaiotaomicron (B. thetaiotaomicron) increased in NHE3(-/-) terminal ileum and was examined in vitro to determine whether altered Na(+) was sufficient to affect growth. Increased in vitro growth of B. thetaiotaomicron occurred in 43 mM Na(+) correlating with the NHE3(-/-) mouse terminal ileum [Na(+)]. NHE3(-/-) terminal ileum displayed increased fut2 mRNA and fucosylation correlating with B. thetaiotaomicron growth. Inoculation of B. thetaiotaomicron in wild-type and NHE3(-/-) terminal ileum organoids displayed increased fut2 and fucosylation, indicating that B. thetaiotaomicron alone is sufficient for the increased fucosylation seen in vivo. These data demonstrate that loss of NHE3 alters the intestinal environment, leading to region-specific changes in bacteria, and shed light on the growth requirements of some gut microbiota members, which is vital for creating better treatments of complex diseases with an altered gut microbiota.
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Affiliation(s)
- Melinda A. Engevik
- Departments of 1Molecular and Cellular Physiology and ,3Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Eitaro Aihara
- Departments of 1Molecular and Cellular Physiology and ,3Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Marshall H. Montrose
- Departments of 1Molecular and Cellular Physiology and ,3Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Gary E. Shull
- 2Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati; ,3Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Daniel J. Hassett
- 2Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati;
| | - Roger T. Worrell
- Departments of 1Molecular and Cellular Physiology and ,3Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
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23
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Torgomyan H, Ohanyan V, Blbulyan S, Trchounian A. Changes in ion transport through membranes, ATPase activity and antibiotics effects in Enterococcus hirae after low intensity electromagnetic irradiation of 51.8 and 53.0 GHz frequencies. Biophysics (Nagoya-shi) 2013. [DOI: 10.1134/s0006350913040167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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24
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Ran S, He Z, Liang J. Survival of Enterococcus faecalis during alkaline stress: changes in morphology, ultrastructure, physiochemical properties of the cell wall and specific gene transcripts. Arch Oral Biol 2013; 58:1667-76. [PMID: 24112733 DOI: 10.1016/j.archoralbio.2013.08.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/19/2013] [Accepted: 08/28/2013] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The aim of this investigation was to study the biochemical mechanisms employed by the endodontic pathogen Enterococcus faecalis to survive alkaline environment during biofilm formation. DESIGN E. faecalis ATCC33186 was inoculated in media at pH 7, 9, 10 and 11 for biofilm formation. The morphology and ultrastructure of biofilm cells were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The physiochemical properties of the cell wall were investigated by measuring the hydrophobicity and Na(+)K(+)-ATPase and H(+)K(+)-ATPase activity. The expression of stress and virulence genes was quantified by real-time quantitative polymerase chain reaction. RESULTS E. faecalis grown in alkaline medium developed an irregular shape and asymmetrical septation. The activity of Na(+)K(+)-ATPase increased dramatically with rising pH, whereas the activity of H(+)K(+)-ATPase exhibited no increase, except at pH 10. A marked increase in cell surface hydrophobicity was also observed with increased pH and time. In addition, transcription of most of the genes tested increased 2- to 15-fold at pH 9 or 10 compared with pH 7 and increased more than 50-fold at pH 11, which is generally recognised as nearly lethal stress. CONCLUSIONS E. faecalis survival and biofilm formation under alkaline stress was unrelated to H(+)K(+)-ATPase but was correlated with an increase in Na(+)K(+)-ATPase activity and cell-surface hydrophobicity in addition to the up-regulation of genes involved in stress response and biofilm formation. These characteristics may explain why E. faecalis resists alkaline root canal medications.
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Affiliation(s)
- Shujun Ran
- Department of Endodontics and Operative Dentistry, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, No. 639, Zhizaoju Road, Shanghai 200011, China
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25
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Wylie CE, Shaw DJ, Fordyce FM, Lilly A, McGorum BC. Equine grass sickness in Scotland: A case-control study of signalment- and meteorology-related risk factors. Equine Vet J 2013; 46:64-71. [DOI: 10.1111/evj.12077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 02/22/2013] [Indexed: 11/29/2022]
Affiliation(s)
- C. E. Wylie
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
| | - D. J. Shaw
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
| | | | - A. Lilly
- James Hutton Institute; Aberdeen UK
| | - B. C. McGorum
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
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26
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Baykov AA, Malinen AM, Luoto HH, Lahti R. Pyrophosphate-fueled Na+ and H+ transport in prokaryotes. Microbiol Mol Biol Rev 2013; 77:267-76. [PMID: 23699258 PMCID: PMC3668671 DOI: 10.1128/mmbr.00003-13] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In its early history, life appeared to depend on pyrophosphate rather than ATP as the source of energy. Ancient membrane pyrophosphatases that couple pyrophosphate hydrolysis to active H(+) transport across biological membranes (H(+)-pyrophosphatases) have long been known in prokaryotes, plants, and protists. Recent studies have identified two evolutionarily related and widespread prokaryotic relics that can pump Na(+) (Na(+)-pyrophosphatase) or both Na(+) and H(+) (Na(+),H(+)-pyrophosphatase). Both these transporters require Na(+) for pyrophosphate hydrolysis and are further activated by K(+). The determination of the three-dimensional structures of H(+)- and Na(+)-pyrophosphatases has been another recent breakthrough in the studies of these cation pumps. Structural and functional studies have highlighted the major determinants of the cation specificities of membrane pyrophosphatases and their potential use in constructing transgenic stress-resistant organisms.
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Affiliation(s)
- Alexander A. Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Anssi M. Malinen
- Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland
| | - Heidi H. Luoto
- Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland
| | - Reijo Lahti
- Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland
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The Effects of Manganese (II) But Not Nickel (II) Ions on Enterococcus hirae Cell Growth, Redox Potential Decrease, and Proton-Coupled Membrane Transport. Cell Biochem Biophys 2013; 67:1301-6. [DOI: 10.1007/s12013-013-9662-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rosinski-Chupin I, Sauvage E, Mairey B, Mangenot S, Ma L, Da Cunha V, Rusniok C, Bouchier C, Barbe V, Glaser P. Reductive evolution in Streptococcus agalactiae and the emergence of a host adapted lineage. BMC Genomics 2013; 14:252. [PMID: 23586779 PMCID: PMC3637634 DOI: 10.1186/1471-2164-14-252] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/01/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND During host specialization, inactivation of genes whose function is no more required is favored by changes in selective constraints and evolutionary bottlenecks. The Gram positive bacteria Streptococcus agalactiae (also called GBS), responsible for septicemia and meningitis in neonates also emerged during the seventies as a cause of severe epidemics in fish farms. To decipher the genetic basis for the emergence of these highly virulent GBS strains and of their adaptation to fish, we have analyzed the genomic sequence of seven strains isolated from fish and other poikilotherms. RESULTS Comparative analysis shows that the two groups of GBS strains responsible for fish epidemic diseases are only distantly related. While strains belonging to the clonal complex 7 cannot be distinguished from their human CC7 counterparts according to their gene content, strains belonging to the ST260-261 types probably diverged a long time ago. In this lineage, specialization to the fish host was correlated with a massive gene inactivation and broad changes in gene expression. We took advantage of the low level of sequence divergence between GBS strains and of the emergence of sublineages to reconstruct the different steps involved in this process. Non-homologous recombination was found to have played a major role in the genome erosion. CONCLUSIONS Our results show that the early phase of genome reduction during host specialization mostly involves accumulation of small and likely reversible indels, followed by a second evolutionary step marked by a higher frequency of large deletions.
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Affiliation(s)
- Isabelle Rosinski-Chupin
- Unité de Biologie des Bactéries Pathogènes à Gram Positif, 28 rue du Docteur Roux, Paris Cedex 15, France.
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Gandi P, Vasireddi SR, Gurram SR, Darasani K. Evaluation of the Antibacterial efficacy of Omeprazole with Sodium Hypochlorite as an Endodontic Irrigating Solution- An Invivo Study. J Int Oral Health 2013; 5:14-20. [PMID: 24155586 PMCID: PMC3768071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 02/22/2013] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Proton pump inhibitors are used in endodontic disinfection of root canals for elimination of enterococcus faecalis. This invivo study on Wistner Rats is carried out to determine antimicrobial efficacy of proton pump inhibitor in combination with sodium hypochlorite & Mixture of Isomer of tetracycline, acid and detergent (MTAD) against E. Faecalis Materials & Methods: Periapical lesions were induced on the 30 Incisor teeth of 30 male Wistner rats (10per group). After 28 days, root canals of each tooth were instrumented to 35# k file, during the process of instrumentation canals were irrigated with their respective irrigation solutions. Group-1: 2% CHX + 5.2% NaOCL, Group-2: MTAD(Dentsply Tulsa Dental, Tulsa, OK) + 5.2% NaOCL, Group-3: 8.5% Omeprazole (Dr Reddy's labs private limited - Hyderabad) + 5.2% NaOCL. Microbiological samples were collected by using #35 sterilized paper points after 28 days of inducing periapical lesions, Sample (S1) was collected before instrumentation and Sample (S2) was collected after instrumentation and Irrigation data were subjected to analysis of variance, followed by Newman Keuls Post Hoc test. RESULTS Microbiological Analysis revealed significant decrease of colony forming units from S1 to S2 Samples in all the 3 groups. CONCLUSION Our data showed that association of Omeprazole with NaOCL showed a superior antibacterial efficacy against Enterococcus faecalis in comparision with other irrigants. Key words: Sodium Hypochlorite, Chlorhexidine, Gluconate, MTAD, Omeprazole.
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Affiliation(s)
- Padma Gandi
- Department of Conservative Dentistry & Endodontics, SVS Institute of Dental Sciences, Andhra Pradesh, India
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Koch-Koerfges A, Pfelzer N, Platzen L, Oldiges M, Bott M. Conversion of Corynebacterium glutamicum from an aerobic respiring to an aerobic fermenting bacterium by inactivation of the respiratory chain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:699-708. [PMID: 23416842 DOI: 10.1016/j.bbabio.2013.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/25/2013] [Accepted: 02/05/2013] [Indexed: 02/03/2023]
Abstract
In this study a comparative analysis of three Corynebacterium glutamicum ATCC 13032 respiratory chain mutants lacking either the cytochrome bd branch (ΔcydAB), or the cytochrome bc1-aa3 branch (Δqcr), or both branches was performed. The lack of cytochrome bd oxidase was inhibitory only under conditions of oxygen limitation, whereas the absence of a functional cytochrome bc1-aa3 supercomplex led to decreases in growth rate, biomass yield, respiration and proton-motive force (pmf) and a strongly increased maintenance coefficient under oxygen excess. These results show that the bc1-aa3 supercomplex is of major importance for aerobic respiration. For the first time, a C. glutamicum strain with a completely inactivated aerobic respiratory chain was obtained (ΔcydABΔqcr), named DOOR (devoid of oxygen respiration), which was able to grow aerobically in BHI (brain-heart infusion) glucose complex medium with a 70% reduced biomass yield compared to the wild type. Surprisingly, reasonable aerobic growth was also possible in glucose minimal medium after supplementation with peptone. Under these conditions, the DOOR strain displayed a fermentative type of catabolism with l-lactate as major and acetate and succinate as minor products. The DOOR strain had about 2% of the oxygen consumption rate of the wild type, showing the absence of additional terminal oxidases. The pmf of the DOOR mutant was reduced by about 30% compared to the wild type. Candidates for pmf generation in the DOOR strain are succinate:menaquinone oxidoreductase, which probably can generate pmf in the direction of fumarate reduction, and F1FO-ATP synthase, which can couple ATP hydrolysis to the export of protons.
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Membrane-integral pyrophosphatase subfamily capable of translocating both Na+ and H+. Proc Natl Acad Sci U S A 2013; 110:1255-60. [PMID: 23297210 DOI: 10.1073/pnas.1217816110] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the strategies used by organisms to adapt to life under conditions of short energy supply is to use the by-product pyrophosphate to support cation gradients in membranes. Transport reactions are catalyzed by membrane-integral pyrophosphatases (PPases), which are classified into two homologous subfamilies: H(+)-transporting (found in prokaryotes, protists, and plants) and Na(+)-transporting (found in prokaryotes). Transport activities have been believed to require specific machinery for each ion, in accordance with the prevailing paradigm in membrane transport. However, experiments using a fluorescent pH probe and (22)Na(+) measurements in the current study revealed that five bacterial PPases expressed in Escherichia coli have the ability to simultaneously translocate H(+) and Na(+) into inverted membrane vesicles under physiological conditions. Consistent with data from phylogenetic analyses, our results support the existence of a third, dual-specificity bacterial Na(+),H(+)-PPase subfamily, which apparently evolved from Na(+)-PPases. Interestingly, genes for Na(+),H(+)-PPase have been found in the major microbes colonizing the human gastrointestinal tract. The Na(+),H(+)-PPases require Na(+) for hydrolytic and transport activities and are further activated by K(+). Based on ionophore effects, we conclude that the Na(+) and H(+) transport reactions are electrogenic and do not result from secondary antiport effects. Sequence comparisons further disclosed four Na(+),H(+)-PPase signature residues located outside the ion conductance channel identified earlier in PPases using X-ray crystallography. Our results collectively support the emerging paradigm that both Na(+) and H(+) can be transported via the same mechanism, with switching between Na(+) and H(+) specificities requiring only subtle changes in the transporter structure.
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Torgomyan H, Ohanyan V, Blbulyan S, Kalantaryan V, Trchounian A. Electromagnetic irradiation of Enterococcus hirae at low-intensity 51.8- and 53.0-GHz frequencies: changes in bacterial cell membrane properties and enhanced antibiotics effects. FEMS Microbiol Lett 2012; 329:131-7. [DOI: 10.1111/j.1574-6968.2012.02512.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/15/2012] [Accepted: 01/24/2012] [Indexed: 11/26/2022] Open
Affiliation(s)
- Heghine Torgomyan
- Department of Biophysics; Faculty of Radiophysics; Yerevan State University; Yerevan; Armenia
| | - Vahe Ohanyan
- Department of Biophysics; Faculty of Radiophysics; Yerevan State University; Yerevan; Armenia
| | - Syuzanna Blbulyan
- Department of Medical Biology and Bioengineering; Russian-Armenian (Slavonic) State University; Yerevan; Armenia
| | - Vitaly Kalantaryan
- Department of Radiophysics of High Frequencies and Telecommunication; Faculty of Radiophysics; Yerevan State University; Yerevan; Armenia
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Nyanga-Koumou AP, Ouoba LII, Kobawila SC, Louembe D. Response mechanisms of lactic acid bacteria to alkaline environments: a review. Crit Rev Microbiol 2011; 38:185-90. [PMID: 22168378 DOI: 10.3109/1040841x.2011.640978] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Regulation of the cytoplasmic or internal pH (pHin) is a fundamental requirement for the survival and viability of bacteria. The optimum pHin for most bacteria is near the neutral point (pH 7.0). Therefore, bacteria may have some strategies to adapt themselves to the acidity or alkalinity of cytoplasm. As other microorganisms, lactic acid bacteria (LAB) are able to maintain a neutral or near neutral cytoplasmic pH even when the pH of the external medium varies. Mechanisms facilitating survival and growth under alkaline conditions of LAB are reviewed. These mechanisms are: (i) the active potassium extrusion and the potassium-proton antiport system, (ii) the sodium-proton antiport system, (iii) the proton-translocating adenosine triphosphatase (ATPase), (iv) the formation of transmembrane proton gradients (ΔpH) in a reversed direction, and (v) the adaptation, cross-protection, and changes in protein synthesis.
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Affiliation(s)
- Armand P Nyanga-Koumou
- Département de Biologie Cellulaire et Moléculaire, Faculté des Sciences, Université Marien N'Gouabi, Brazzaville, Congo
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Poladyan A, Trchounian A. Transport of protons and potassium ions across the membranes of bacteria Enterococcus hirae dependent on ATP and nicotinamide adenine dinucleotides. Biophysics (Nagoya-shi) 2011. [DOI: 10.1134/s0006350911040208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
Diverse mechanisms for pH sensing and cytoplasmic pH homeostasis enable most bacteria to tolerate or grow at external pH values that are outside the cytoplasmic pH range they must maintain for growth. The most extreme cases are exemplified by the extremophiles that inhabit environments with a pH of below 3 or above 11. Here, we describe how recent insights into the structure and function of key molecules and their regulators reveal novel strategies of bacterial pH homeostasis. These insights may help us to target certain pathogens more accurately and to harness the capacities of environmental bacteria more efficiently.
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Affiliation(s)
- Terry A. Krulwich
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, Box 1603, 1 Gustave L. Levy Place, New York, NY 10029, USA; Tel. 212-241-7280; Fax. 212-996-7214
| | - George Sachs
- Departments of Physiology and Medicine, David Geffen School of Medicine at UCLA, 405 Hilgard Ave., Los Angeles, California 90024, USA Tel. 310-268-3923, Fax 310-312-9478
| | - Etana Padan
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem 91904, Israel, Tel. 972 2 6585094, Fax 972 2 658947
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36
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Transcriptomic and phenotypic responses of Listeria monocytogenes strains possessing different growth efficiencies under acidic conditions. Appl Environ Microbiol 2010; 76:4836-50. [PMID: 20511423 DOI: 10.1128/aem.00315-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In an experiment delineating aciduric strains, food and clinical Listeria monocytogenes isolates tended to produce the most biomass whereas ovine and avian strains produced comparatively less biomass when exposed to high levels of sodium diacetate (SD) and potassium sorbate. Compared to reference strains that exhibited greater acid sensitivity, representative food isolates with comparatively good growth capacities in the presence of 21 mM SD at pH 5.0 accumulated reduced levels of acetate anion and K(+) ion. The aciduric nature of SD-resistant strains was also reflected by comparatively high tolerance to pH 2.4 (HCl) acid challenges, a property boosted by the presence of SD. Exposure to elevated levels of SD (21 mM SD at pH 5.0) was found to have broad effects on gene expression, as differentiated from effects caused by mildly acidic conditions (pH 5.0). SD-resistant strain FW04/0025 was more responsive to elevated SD, increasing the expression of 222 genes (>2-fold change [P < 0.05]), compared to the more sensitive EGD reference strain, which exhibited increases in expression of 112 genes. Key differences between the strains in relation to SD-enhanced transcripts were notably associated with the cell envelope, oxidative stress management, and intermediary metabolism. SD thus appears to differentially influence growth efficiency and survival of strains, under conditions relevant to acidic foods, that could be due to altered cell wall and metabolic phenotypes.
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Slonczewski JL, Fujisawa M, Dopson M, Krulwich TA. Cytoplasmic pH measurement and homeostasis in bacteria and archaea. Adv Microb Physiol 2009; 55:1-79, 317. [PMID: 19573695 DOI: 10.1016/s0065-2911(09)05501-5] [Citation(s) in RCA: 289] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Of all the molecular determinants for growth, the hydronium and hydroxide ions are found naturally in the widest concentration range, from acid mine drainage below pH 0 to soda lakes above pH 13. Most bacteria and archaea have mechanisms that maintain their internal, cytoplasmic pH within a narrower range than the pH outside the cell, termed "pH homeostasis." Some mechanisms of pH homeostasis are specific to particular species or groups of microorganisms while some common principles apply across the pH spectrum. The measurement of internal pH of microbes presents challenges, which are addressed by a range of techniques under varying growth conditions. This review compares and contrasts cytoplasmic pH homeostasis in acidophilic, neutralophilic, and alkaliphilic bacteria and archaea under conditions of growth, non-growth survival, and biofilms. We present diverse mechanisms of pH homeostasis including cell buffering, adaptations of membrane structure, active ion transport, and metabolic consumption of acids and bases.
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Gong Y, Tian XL, Sutherland T, Sisson G, Mai J, Ling J, Li YH. Global transcriptional analysis of acid-inducible genes in Streptococcus mutans: multiple two-component systems involved in acid adaptation. MICROBIOLOGY-SGM 2009; 155:3322-3332. [PMID: 19608608 DOI: 10.1099/mic.0.031591-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus mutans in dental biofilms is regularly exposed to cycles of acidic pH during the ingestion of fermentable dietary carbohydrates. The ability of S. mutans to tolerate low pH is crucial for its virulence and pathogenesis in dental caries. To better understand its acid tolerance mechanisms, we performed genome-wide transcriptional analysis of S. mutans in response to an acidic pH signal. The preliminary results showed that adaptation of S. mutans to pH 5.5 induced differential expression of nearly 14 % of the genes in the genome, including 169 upregulated genes and 108 downregulated genes, largely categorized into nine functional groups. One of the most interesting findings was that the genes encoding multiple two-component systems (TCSs), including CiaHR, LevSR, LiaSR, ScnKR, Hk/Rr1037/1038 and ComDE, were upregulated during acid adaptation. Real-time qRT-PCR confirmed the same trend in the expression profiles of these genes at pH 5.5. To determine the roles of these transduction systems in acid adaptation, mutants with a deletion of the histidine-kinase-encoding genes were constructed and assayed for the acid tolerance response (ATR). The results revealed that inactivation of each of these systems resulted in a mutant that was impaired in ATR, since pre-exposure of these mutants to pH 5.5 did not induce the same level of protection against lethal pH levels as the parent did. A competitive fitness assay showed that all the mutants were unable to compete with the parent strain for persistence in dual-strain mixed cultures at acidic pH, although, with the exception of the mutant in liaS, little effect was observed at neutral pH. The evidence from this study suggests that the multiple TCSs are required for S. mutans to orchestrate its signal transduction networks for optimal adaptation to acidic pH.
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Affiliation(s)
- Yongxing Gong
- Department of Applied Oral Sciences, Dalhousie University, Halifax, Canada
| | - Xiao-Lin Tian
- Department of Applied Oral Sciences, Dalhousie University, Halifax, Canada
| | - Tara Sutherland
- Department of Applied Oral Sciences, Dalhousie University, Halifax, Canada
| | - Gary Sisson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Junni Mai
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, PR China.,Department of Applied Oral Sciences, Dalhousie University, Halifax, Canada
| | - Junqi Ling
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, PR China
| | - Yung-Hua Li
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada.,Department of Applied Oral Sciences, Dalhousie University, Halifax, Canada
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Ohanyan V, Sarkisyan A, Tadevosyan A, Trchounian A. The effect of low-intensity coherent extremely high frequency electromagnetic radiation on growth parameters for Enterococcus hirae bacteria. Biophysics (Nagoya-shi) 2009. [DOI: 10.1134/s0006350908050151] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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40
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Papadimitriou K, Pratsinis H, Nebe-von-Caron G, Kletsas D, Tsakalidou E. Acid tolerance of Streptococcus macedonicus as assessed by flow cytometry and single-cell sorting. Appl Environ Microbiol 2007; 73:465-76. [PMID: 17098924 PMCID: PMC1796968 DOI: 10.1128/aem.01244-06] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 10/27/2006] [Indexed: 12/27/2022] Open
Abstract
An in situ flow cytometric viability assay employing carboxyfluorescein diacetate and propidium iodide was used to identify Streptococcus macedonicus acid tolerance phenotypes. The logarithmic-phase acid tolerance response (L-ATR) was evident when cells were (i) left to autoacidify unbuffered medium, (ii) transiently exposed to nonlethal acidic pH, or (iii) systematically grown under suboptimal acidic conditions (acid habituation). Stationary-phase ATR was also detected; this phenotype was gradually degenerated while cells resided at this phase. Single-cell analysis of S. macedonicus during induction of L-ATR revealed heterogeneity in both the ability and the rate of tolerance acquisition within clonal populations. L-ATR was found to be partially dependent on de novo protein synthesis and compositional changes of the cell envelope. Interestingly, acid-habituated cells were interlaced in lengthier chains and exhibited an irregular pattern of active peptidoglycan biosynthesis sites when probed with BODIPY FL vancomycin. L-ATR caused cells to retain their membrane potential after lethal challenge, as judged by ratiometric analysis with oxonol [DiBAC(4)(3)]. Furthermore, F-ATPase was important during the induction of L-ATR, but in the case of a fully launched response, inhibition of F-ATPase affected acid resistance only partially. Activities of both F-ATPase and the glucose-specific phosphoenolpyruvate-dependent phosphotransferase system were increased after L-ATR induction, distinguishing S. macedonicus from oral streptococci. Finally, the in situ viability assessment was compared to medium-based recovery after single-cell sorting, revealing that the culturability of subpopulations with identical fluorescence characteristics is dependent on the treatments imposed to the cells prior to acid challenge.
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Affiliation(s)
- Konstantinos Papadimitriou
- Laboratory of Dairy Research, Department of Food Science and Technology, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
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Aslangul E, Massias L, Meulemans A, Chau F, Andremont A, Courvalin P, Fantin B, Ruimy R. Acquired gentamicin resistance by permeability impairment in Enterococcus faecalis. Antimicrob Agents Chemother 2006; 50:3615-21. [PMID: 17065620 PMCID: PMC1635182 DOI: 10.1128/aac.00390-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococci are intrinsically resistant to low levels of aminoglycosides. We previously selected in vitro and in vivo Enterococcus faecalis with intermediate-level resistance to gentamicin that did not abolish synergism with a cell-wall-active agent (E. Aslangul et al., Antimicrob. Agents Chemother. 49:4144-4148, 2005). The aim of this study was to investigate the mechanism of resistance to gentamicin in the 1688-G3 third-step mutant (MIC, 512 microg/ml) of E. faecalis JH2-2. No mutations were found in the genes for L6 ribosomal protein and the four copies of 16S rRNA. Production of a known aminoglycoside-modifying enzyme was unlikely due to the distinct resistance phenotype and absence of the corresponding genes. Efflux was also unlikely since ethidium bromide MICs were similar for JH2-2 and 1688-G3 and since the pump inhibitors reserpine and verapamil had no effect on gentamicin resistance in both strains. To study gentamicin accumulation, we developed a nonisotopic method based on a fluorescent polarization immunoassay. Impaired gentamicin accumulation was observed in 1688-G3 compared to JH2-2 and was only partially reversible by the N,N'-dicyclohexylcarbodiimide (DCCD) uncoupler agent. The lower sensitivity of 1688-G3 to DCCD suggested alteration of the FoF1-ATPase. However, no mutations were detected in the structural genes (atp) for the Fo channel and no difference in transcript levels of atpB and atpE was found between 1688-G3 and JH2-2. Our data are compatible with acquisition of intermediate-level gentamicin resistance by uptake impairment in E. faecalis.
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Affiliation(s)
- Elisabeth Aslangul
- EA 3964, Faculté de Médecine de l'Université Paris 7, 46, rue Henri Huchard, 75870 Paris Cedex 18, France.
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Poladyan A, Kirakosyan G, Trchounian A. Growth and proton-potassium exchange in the bacterium Enterococcus hirae: the effect of protonophore and the role of redox potential. Biophysics (Nagoya-shi) 2006. [DOI: 10.1134/s0006350906030171] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Poladyan A, Trchounian A. The increase in the number of accessible SH-groups in the enterococcal membrane vesicles by ATP and nicotinamide adenine dinucleotides. Curr Microbiol 2006; 52:300-4. [PMID: 16550463 DOI: 10.1007/s00284-005-0293-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Accepted: 11/03/2005] [Indexed: 11/27/2022]
Abstract
The number of accessible SH groups was determined in membrane vesicles prepared from Enterococcus hirae grown under anaerobic conditions at alkaline pH (pH 8.0). Addition of ATP or nicotinamide adenine dinucleotides (NAD(+) +NADH) to the vesicles caused a approximately 4-fold or approximately 1.9-fold increase in the number of SH-groups, respectively. This was inhibited by treatment with N-ethylmaleimide. The increase was significant when ATP and NAD(+) +NADH both were added. The change was lacking in the presence of the F0F1-ATPase inhibitors N,N'-diclohexylcarbodiimide or sodium azide. This was also absent in atp mutant with defect in the F0F1-ATPase and, in addition, it was less in potassium ion-free medium. These results are correlated with data about K+-dependent F0F1-ATPase activity, suggesting a relationship between the F0F1-ATPase and K+ uptake Trk-like system. The latter may be regulated by NAD or NADH mediating conformational changes.
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Affiliation(s)
- Anna Poladyan
- Department of Biophysics of the Biological Faculty, Yerevan State University, 1 Alex Manoukian Str., 375025, Yerevan, Armenia
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Martínez-Cuesta MC, Requena T, Peláez C. Cell membrane damage induced by lacticin 3147 enhances aldehyde formation in Lactococcus lactis IFPL730. Int J Food Microbiol 2006; 109:198-204. [PMID: 16504327 DOI: 10.1016/j.ijfoodmicro.2006.01.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 09/19/2005] [Accepted: 01/02/2006] [Indexed: 11/30/2022]
Abstract
Amino acid catabolism is mainly initiated in Lactococcus lactis by a transamination reaction that leads to the formation of alpha-keto acids. In addition, a novel alpha-keto acid decarboxylase enzyme, rare in lactic acid bacteria, responsible for the conversion of alpha-keto acids into aldehydes has been reported in L. lactis IFPL730. The effect of lacticin 3147-induced cell damage on both amino acid transamination and alpha-keto acid decarboxylation by L. lactis IFPL730 leading to the formation of aldehydes from amino acids was investigated. Cell membrane permeabilization induced by lacticin 3147 facilitated the diffusion of amino acids into the cells and thus, enhanced amino acid transamination and formation of alpha-keto acids. However, alpha-keto acid decarboxylation was not affected by cell membrane permeabilization since decarboxylation of alpha-keto acids in both control and lacticin 3147-treated cells were similar, suggesting that these substrates could freely diffuse inside the cells. Nevertheless, the formation of 2-methylbutyraldehyde from isoleucine was enhanced in lacticin 3147-treated cells. The increase in alpha-keto acids formation rate by L. lactis IFPL730 due to lacticin 3147-induced cell damage, led to a concomitant increase in the subsequent decarboxylation reaction that complete the metabolic pathway to aldehyde production from amino acids. The present study points out to the use of the food grade lacticin 3147 along with L. lactis IFPL730 as a valuable tool in the development of cheese flavour.
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Affiliation(s)
- M Carmen Martínez-Cuesta
- Department of Dairy Science and Technology, Instituto del Frío, CSIC, José Antonio Novais 10, Ciudad Universitaria, 28040 Madrid, Spain.
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Karandashova IV, Elanskaya IV. Genetic Control and Mechanisms of Salt and Hyperosmotic Stress Resistance in Cyanobacteria. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-006-0001-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Lolkema JS, Chaban Y, Boekema EJ. Subunit composition, structure, and distribution of bacterial V-type ATPases. J Bioenerg Biomembr 2004; 35:323-35. [PMID: 14635778 DOI: 10.1023/a:1025776831494] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The overall structure of V-ATPase complexes resembles that of F-type ATPases, but the stalk region is different and more complex. Database searches followed by sequence analysis of the five water-soluble stalk region subunits C-G revealed that (i) to date V-ATPases are found in 16 bacterial species, (ii) bacterial V-ATPases are closer to archaeal A-ATPases than to eukaryotic V-ATPases, and (iii) different groups of bacterial V-ATPases exist. Inconsistencies in the nomenclature of types and subunits are addressed. Attempts to assign subunit positions in V-ATPases based on biochemical experiments, chemical cross-linking, and electron microscopy are discussed. A structural model for prokaryotic and eukaryotic V-ATPases is proposed. The prokaryotic V-ATPase is considered to have a central stalk between headpiece and membrane flanked by two peripheral stalks. The eukaryotic V-ATPases have one additional peripheral stalk.
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Affiliation(s)
- Juke S Lolkema
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
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Martín-Galiano AJ, Balsalobre L, Fenoll A, de la Campa AG. Genetic characterization of optochin-susceptible viridans group streptococci. Antimicrob Agents Chemother 2003; 47:3187-94. [PMID: 14506029 PMCID: PMC201122 DOI: 10.1128/aac.47.10.3187-3194.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2003] [Revised: 04/07/2003] [Accepted: 06/20/2003] [Indexed: 11/20/2022] Open
Abstract
Two clinical isolates of viridans group streptococci (VS) with different degrees of susceptibility to optochin (OPT), i.e., fully OPT-susceptible (Opt(s)) VS strain 1162/99 (for which the MIC was equal to that for Streptococcus pneumoniae, 0.75 micro g/ml) and intermediate Opt(s) VS strain 1174/97 (MIC, 6 micro g/ml) were studied. Besides being OPT susceptible, they showed characteristics typical of VS, such as bile insolubility; lack of reaction with pneumococcal capsular antibodies; and lack of hybridization with rRNA (AccuProbe)-, lytA-, and pnl-specific pneumococcal probes. However, these VS Opt(s) strains and VS type strains hybridized with ant, a gene not present in S. pneumoniae. A detailed characterization of the genes encoding the 16S rRNA and SodA classified isolates 1162/99 and 1174/97 as Streptococcus mitis. Analysis of the atpCAB region, which encodes the c, a, and b subunits of the F(0)F(1) H(+)-ATPase, the target of optochin, revealed high degrees of similarity between S. mitis 1162/99 and S. pneumoniae in atpC, atpA, and the N terminus of atpB. Moreover, amino acid identity between S. mitis 1174/97 and S. pneumoniae was found in alpha helix 5 of the a subunit. The organization of the chromosomal region containing the atp operon of the two Opt(s) VS and VS type strains was spr1284-atpC, with spr1284 being located 296 to 556 bp from atpC, whereas in S. pneumoniae this distance was longer than 68 kb. In addition, the gene order in S. pneumoniae was IS1239-74 bp-atpC. The results suggest that the full OPT susceptibility of S. mitis 1162/99 is due to the acquisition of atpC, atpA, and part of atpB from S. pneumoniae and that the intermediate OPT susceptibility of S. mitis 1174/97 correlates with the amino acid composition of its a subunit.
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Affiliation(s)
- Antonio J Martín-Galiano
- Unidad de Genética Bacteriana (Consejo Superior de Investigaciones Científicas), Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
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Cotter PD, Hill C. Surviving the acid test: responses of gram-positive bacteria to low pH. Microbiol Mol Biol Rev 2003; 67:429-53, table of contents. [PMID: 12966143 PMCID: PMC193868 DOI: 10.1128/mmbr.67.3.429-453.2003] [Citation(s) in RCA: 763] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-positive bacteria possess a myriad of acid resistance systems that can help them to overcome the challenge posed by different acidic environments. In this review the most common mechanisms are described: i.e., the use of proton pumps, the protection or repair of macromolecules, cell membrane changes, production of alkali, induction of pathways by transcriptional regulators, alteration of metabolism, and the role of cell density and cell signaling. We also discuss the responses of Listeria monocytogenes, Rhodococcus, Mycobacterium, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, oral streptococci, and lactic acid bacteria to acidic environments and outline ways in which this knowledge has been or may be used to either aid or prevent bacterial survival in low-pH environments.
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Affiliation(s)
- Paul D Cotter
- Department of Microbiology and National Food Biotechnology Centre, University College Cork, Cork, Ireland
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Swerczek T. Saprotrophic fungi and bacteria and commensal bacteria that infect frost-damaged pastures may be contributing to gut microbial overgrowth and lesions associated with the mare reproductive loss syndrome. J Equine Vet Sci 2002. [DOI: 10.1016/s0737-0806(02)70057-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Martín-Galiano AJ, Gorgojo B, Kunin CM, de la Campa AG. Mefloquine and new related compounds target the F(0) complex of the F(0)F(1) H(+)-ATPase of Streptococcus pneumoniae. Antimicrob Agents Chemother 2002; 46:1680-7. [PMID: 12019076 PMCID: PMC127268 DOI: 10.1128/aac.46.6.1680-1687.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The activities of mefloquine (MFL) and related compounds against previously characterized Streptococcus pneumoniae strains carrying defined amino acid substitutions in the c subunit of the F(0)F(1) H(+)-ATPase were studied. In addition, a series of MFL-resistant (Mfl(r)) strains were isolated and characterized. A good correlation was observed between inhibition of growth and inhibition of the membrane-associated F(0)F(1) H(+)-ATPase activity. MFL was about 10-fold more active than optochin and about 200-fold more active than quinine in inhibiting both the growth and the ATPase activities of laboratory pneumococcal strain R6. Mutant strains were inhibited by the different compounds to different degrees, depending on their specific mutations in the c subunit. The resistant strains studied had point mutations that changed amino acid residues in either the c subunit or the a subunit of the F(0) complex. Changes in the c subunit were located in one of the two transmembrane alpha helices: residues M13, G14, G20, M23, and N24 of helix 1 and residues M44, G47, V48, A49, and V57 of helix 2. Changes in the a subunit were also found in either of the transmembrane alpha helices, helix 5 or 6: residue L186 of helix 5 and residues W206, F209, and S214 of helix 6. These results suggest that the transmembrane helices of the c and a subunits interact and that the mutated residues are important for the structure of the F(0) complex and proton translocation.
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Affiliation(s)
- Antonio Javier Martín-Galiano
- Unidad de Genética Bacteriana (Consejo Superior de Investigaciones Científicas), Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
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