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Hu H, Zhang YY, Ma H, Yang Y, Mei S, Li J, Xu JF, Zhang X. A Supramolecular Naphthalene Diimide Radical Anion with Efficient NIR-II Photothermal Conversion for E. coli-Responsive Photothermal Therapy. Angew Chem Int Ed Engl 2023; 62:e202308513. [PMID: 37607898 DOI: 10.1002/anie.202308513] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/21/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
We report a supramolecular naphthalene diimide (NDI) radical anion with efficient NIR-II photothermal conversion for E. coli-responsive photothermal therapy. The supramolecular radical anion (NDI-2CB[7])⋅- , which is obtained from the E. coli-induced in situ reduction of NDI-2CB[7] neutral complex, formed by the host-guest interaction between an NDI derivative and cucurbit[7]uril (CB[7]), exhibits unexpectedly strong NIR-II absorption and remarkable photothermal conversion capacity in aqueous solution. The NIR-II absorption is caused by the self-assembly of NDI radical anions to form supramolecular dimer radicals in aqueous solution, which is supported by theoretically predicted spectra. The (NDI-2CB[7])⋅- demonstrates excellent NIR-II photothermal antimicrobial activity (>99 %). This work provides a new approach for constructing NIR-II photothermal agents and non-contact treatments for bacterial infections.
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Affiliation(s)
- Hao Hu
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yang-Yang Zhang
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
| | - He Ma
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yuchong Yang
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Shan Mei
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jun Li
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518005, China
| | - Jiang-Fei Xu
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xi Zhang
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
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Poladyan A, Trchounian K, Paloyan A, Minasyan E, Aghekyan H, Iskandaryan M, Khoyetsyan L, Aghayan S, Tsaturyan A, Antranikian G. Valorization of whey-based side streams for microbial biomass, molecular hydrogen, and hydrogenase production. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12609-x. [PMID: 37289241 DOI: 10.1007/s00253-023-12609-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/09/2023]
Abstract
Side streams of the dairy industry are a suitable nutrient source for cultivating microorganisms, producing enzymes, and high-value chemical compounds. The heterotrophic Escherichia coli and chemolithoautotroph Ralstonia eutropha are of major biotechnological interest. R. eutropha is a model organism for producing O2-tolerant [NiFe]-hydrogenases (Hyds) (biocatalysts), and E. coli has found widespread use as an expression platform for producing recombinant proteins, molecular hydrogen (H2), and other valuable products. Aiming at developing suitable cultivation media from side streams of the dairy industry, the pre-treatment (filtration, dilution, and pH adjustment) of cheese (sweet) whey (SW) and curd (acid) whey (AW), with and without the use of ß-glucosidase, has been performed. Growth parameters (oxidation-reduction potential (ORP), pH changes, specific growth rate, biomass formation) of E. coli BW25113 and R. eutropha H16 type strains were monitored during cultivation on filtered and non-filtered SW and AW at 37 °C, pH 7.5 and 30 °C, pH 7.0, respectively. Along with microbial growth, measurements of pH and ORP indicated good fermentative growth. Compared to growth on fructose-nitrogen minimal salt medium (control), a maximum cell yield (OD600 4.0) and H2-oxidizing Hyd activity were achieved in the stationary growth phase for R. eutropha. Hyd-3-dependent H2 production by E. coli utilizing whey as a growth substrate was demonstrated. Moreover, good biomass production and prolonged H2 yields of ~ 5 mmol/L and cumulative H2 ~ 94 mL g/L dry whey (DW) (ß-glucosidase-treated) were observed during the cultivation of the engineered E. coli strain. These results open new avenues for effective whey treatment using thermostable β-glucosidase and confirm whey as an economically viable commodity for biomass and biocatalyst production. KEY POINTS: • Archaeal thermostable β-glucosidase isolated from the metagenome of a hydrothermal spring was used for lactose hydrolysis in whey. • Hydrogenase enzyme activity was induced during the growth of Ralstonia eutropha H16 on whey. • Enhanced biomass and H2 production was shown in a genetically modified strain of Escherichia coli.
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Affiliation(s)
- Anna Poladyan
- Department of Biochemistry, Microbiology, and Biotechnology, Yerevan State University, Yerevan, Armenia, 1 A. Manoukian Str, 0025, Yerevan, Armenia.
- Research Institute of Biology, Biology Faculty, Yerevan State University, 0025, Yerevan, Armenia.
| | - Karen Trchounian
- Department of Biochemistry, Microbiology, and Biotechnology, Yerevan State University, Yerevan, Armenia, 1 A. Manoukian Str, 0025, Yerevan, Armenia
- Research Institute of Biology, Biology Faculty, Yerevan State University, 0025, Yerevan, Armenia
| | - Ani Paloyan
- SPC "Armbiotechnology" NAS RA, Yerevan, Armenia
| | - Ela Minasyan
- Institute of Pharmacy, Yerevan State University, 0025, Yerevan, Armenia
| | - Hayarpi Aghekyan
- Department of Biochemistry, Microbiology, and Biotechnology, Yerevan State University, Yerevan, Armenia, 1 A. Manoukian Str, 0025, Yerevan, Armenia
- Research Institute of Biology, Biology Faculty, Yerevan State University, 0025, Yerevan, Armenia
| | - Meri Iskandaryan
- Department of Biochemistry, Microbiology, and Biotechnology, Yerevan State University, Yerevan, Armenia, 1 A. Manoukian Str, 0025, Yerevan, Armenia
- Research Institute of Biology, Biology Faculty, Yerevan State University, 0025, Yerevan, Armenia
| | | | - Sargis Aghayan
- Research Institute of Biology, Biology Faculty, Yerevan State University, 0025, Yerevan, Armenia
| | - Avetis Tsaturyan
- SPC "Armbiotechnology" NAS RA, Yerevan, Armenia
- Institute of Pharmacy, Yerevan State University, 0025, Yerevan, Armenia
| | - Garabed Antranikian
- Hamburg University of Technology, Institute of Technical Biocatalysis, Hamburg, Germany
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Iskandaryan M, Blbulyan S, Sahakyan M, Vassilian A, Trchounian K, Poladyan A. L-amino acids affect the hydrogenase activity and growth of Ralstonia eutropha H16. AMB Express 2023; 13:33. [PMID: 36932299 PMCID: PMC10023824 DOI: 10.1186/s13568-023-01535-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023] Open
Abstract
Ralstonia eutropha H16 is a chemolithoautotrophic bacterium with O2-tolerant hydrogenase (Hyds) enzymes. Hyds are expressed in the presence of gas mixtures (H2, O2, CO2) or under energy limitation and stress conditions. O2-tolerant Hyds are promising candidates as anode biocatalysts in enzymatic fuel cells (EFCs). Supplementation of 0.5% (w/v) yeast extract to the fructose-nitrogen (FN) growth medium enhanced H2-oxidizing Hyd activity ~ sixfold. Our study aimed to identify key metabolites (L-amino acids (L-AAs) and vitamins) in yeast extract that are necessary for the increased synthesis and activity of Hyds. A decrease in pH and a reduction in ORP (from + 240 ± 5 mV to - 180 mV ± 10 mV values) after 24 h of growth in the presence of AAs were observed. Compared to the FN-medium control, supplementation of 7.0 μmol/ml of the L-AA mixture stimulated the growth of bacteria ~ 1.9 to 2.9 fold, after 72 h. The whole cells' H2-oxidizing Hyd activity was not observed in control samples, whereas the addition of L-AAs, mainly glycine resulted in a maximum of ~ 22 ± 0.5 and 15 ± 0.3 U, g CDW-1 activity after 24 h and 72 h, respectively. Our results suggest a correlation between ORP, pH, and function of Hyds in R. eutropha H16 in the presence of key L-AAs. L-AAs used in small amounts can be proposed as signaling molecules or key components of Hyd maturation. These results are important for the optimization of O2-tolerant Hyds production as anode biocatalysts.
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Affiliation(s)
- Meri Iskandaryan
- Department of Biochemistry, Microbiology, and Biotechnology, Biology Faculty, YSU, Yerevan, Armenia
| | - Syuzanna Blbulyan
- Department of Biochemistry, Microbiology, and Biotechnology, Biology Faculty, YSU, Yerevan, Armenia
| | - Mayramik Sahakyan
- Department of Biochemistry, Microbiology, and Biotechnology, Biology Faculty, YSU, Yerevan, Armenia
| | - Anait Vassilian
- Research Institute of Biology, Biology Faculty, YSU, Yerevan, Armenia
| | - Karen Trchounian
- Department of Biochemistry, Microbiology, and Biotechnology, Biology Faculty, YSU, Yerevan, Armenia.,Research Institute of Biology, Biology Faculty, YSU, Yerevan, Armenia
| | - Anna Poladyan
- Department of Biochemistry, Microbiology, and Biotechnology, Biology Faculty, YSU, Yerevan, Armenia. .,Research Institute of Biology, Biology Faculty, YSU, Yerevan, Armenia.
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Wu D, Zhang Z, Li X, Han J, Hu Q, Yu Y, Mao Z. Cucurbit[10]uril-based supramolecular radicals: Powerful arms to kill facultative anaerobic bacteria. J Control Release 2023; 354:626-634. [PMID: 36681280 DOI: 10.1016/j.jconrel.2023.01.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 01/11/2023] [Accepted: 01/14/2023] [Indexed: 01/23/2023]
Abstract
Two water-soluble supramolecular complexes (CB[10]⊃PSA and CB[10]⊃TPE-cyc) are constructed based on the host-guest interaction between cucurbit[10]uril (CB[10]) and perylene diimide derivative (PSA) or tetracationic cyclophane (TPE-cyc). Attributing to the matched redox potential, both supramolecular complexes can be specifically reduced into corresponding supramolecular radical cations or anions by facultative anaerobic E. coli. Benefiting from the strong near-infrared (NIR) absorption, CB[10]⊃PSA radical anions and CB[10]⊃TPE-cyc radical cations act as efficient NIR photosensitizers and perform an excellent antimicrobial activity (close to 100%) via PTT. In addition, the biocompatibility of TPE-cyc is notably improved under the protection of CB[10], guaranteeing its biosafety for in vivo application. CB[10]⊃PSA radical anions and CB[10]⊃TPE-cyc radical cations are in situ generated in the E. coli-infected abscess of mice and effectively inhibit the bacterial infection without obvious system toxicity. It is anticipated that this supramolecular strategy may pave a new way for the selective bacteria inhibition to regulate the balance of different bacterial flora.
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Affiliation(s)
- Dan Wu
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Zhankui Zhang
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Xinyue Li
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Jin Han
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China..
| | - Qinglian Hu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, PR China..
| | - Yuan Yu
- Zhejiang Provincial Key Laboratory of Fiber Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018, PR China..
| | - Zhengwei Mao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, PR China..
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Arbter P, Widderich N, Utesch T, Hong Y, Zeng AP. Control of redox potential in a novel continuous bioelectrochemical system led to remarkable metabolic and energetic responses of Clostridium pasteurianum grown on glycerol. Microb Cell Fact 2022; 21:178. [PMID: 36050762 PMCID: PMC9434860 DOI: 10.1186/s12934-022-01902-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 08/11/2022] [Indexed: 11/25/2022] Open
Abstract
Background Electro-fermentation (EF) is an emerging tool for bioprocess intensification. Benefits are especially expected for bioprocesses in which the cells are enabled to exchange electrons with electrode surfaces directly. It has also been demonstrated that the use of electrical energy in BES can increase bioprocess performance by indirect secondary effects. In this case, the electricity is used to alter process parameters and indirectly activate desired pathways. In many bioprocesses, oxidation-reduction potential (ORP) is a crucial process parameter. While C. pasteurianum fermentation of glycerol has been shown to be significantly influenced electrochemically, the underlying mechanisms are not clear. To this end, we developed a system for the electrochemical control of ORP in continuous culture to quantitatively study the effects of ORP alteration on C. pasteurianum by metabolic flux analysis (MFA), targeted metabolomics, sensitivity and regulation analysis. Results In the ORP range of −462 mV to −250 mV, the developed algorithm enabled a stable anodic electrochemical control of ORP at desired set-points and a fixed dilution rate of 0.1 h−1. An overall increase of 57% in the molar yield for 1,3-propanediol was observed by an ORP increase from −462 to −250 mV. MFA suggests that C. pasteurianum possesses and uses cellular energy generation mechanisms in addition to substrate-level phosphorylation. The sensitivity analysis showed that ORP exerted its strongest impact on the reaction of pyruvate-ferredoxin-oxidoreductase. The regulation analysis revealed that this influence is mainly of a direct nature. Hence, the observed metabolic shifts are primarily caused by direct inhibition of the enzyme upon electrochemical production of oxygen. A similar effect was observed for the enzyme pyruvate-formate-lyase at elevated ORP levels. Conclusions The results show that electrochemical ORP alteration is a suitable tool to steer the metabolism of C. pasteurianum and increase product yield for 1,3-propanediol in continuous culture. The approach might also be useful for application with further anaerobic or anoxic bioprocesses. However, to maximize the technique's efficiency, it is essential to understand the chemistry behind the ORP change and how the microbial system responds to it by transmitted or direct effects. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01902-5.
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Affiliation(s)
- Philipp Arbter
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestraße 15, 21073, Hamburg, Germany
| | - Niklas Widderich
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestraße 15, 21073, Hamburg, Germany
| | - Tyll Utesch
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestraße 15, 21073, Hamburg, Germany
| | - Yaeseong Hong
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestraße 15, 21073, Hamburg, Germany
| | - An-Ping Zeng
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310024, Zhejiang, China.
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Hu H, Wang H, Yang Y, Xu JF, Zhang X. A Bacteria-Responsive Porphyrin for Adaptable Photodynamic/Photothermal Therapy. Angew Chem Int Ed Engl 2022; 61:e202200799. [PMID: 35332634 DOI: 10.1002/anie.202200799] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Indexed: 12/17/2022]
Abstract
We report a cationic porphyrin 5,10,15,20-tetrakis-(4-N-methylpyridyl)-porphyrin (TMPyP) that can respond to specific bacteria, followed by adaptable photodynamic/photothermal therapy processes. TMPyP could be reduced to phlorin by facultative anaerobes with a strong reducing ability such as E. coli and S. typhimurium in hypoxic environments, possessing strong NIR absorption and remarkable photothermal conversion capacity, thus demonstrating excellent antimicrobial activity (>99 %) by photothermal therapy. While in an aerobic environment with aerobic bacteria, TMPyP functioned as a typical photosensitizer that killed bacteria effectively (>99.9 %) by photodynamic therapy. By forming a host-guest complex with cucurbit[7]uril, the biocompatibility of TMPyP significantly improved. This kind of bacteria-responsive porphyrin shows specificity and adaptivity in antimicrobial treatment and holds potential in non-invasive treatments of bacterial infections.
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Affiliation(s)
- Hao Hu
- Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Hua Wang
- Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yuchong Yang
- Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jiang-Fei Xu
- Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xi Zhang
- Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China
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Hu H, Wang H, Yang Y, Xu J, Zhang X. A Bacteria‐Responsive Porphyrin for Adaptable Photodynamic/Photothermal Therapy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hao Hu
- Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China
| | - Hua Wang
- Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China
| | - Yuchong Yang
- Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China
| | - Jiang‐Fei Xu
- Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China
| | - Xi Zhang
- Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China
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8
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Akermann A, Weiermüller J, Chodorski JN, Nestriepke MJ, Baclig MT, Ulber R. Optimization of bioprocesses with Brewers’ spent grain and
Cellulomonas uda. Eng Life Sci 2021; 22:132-151. [PMID: 35382540 PMCID: PMC8961044 DOI: 10.1002/elsc.202100053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/05/2021] [Accepted: 07/29/2021] [Indexed: 01/09/2023] Open
Abstract
Brewers’ spent grain (BSG) is a low‐value by‐product of the brewing process, which is produced in large quantities every year. In this study, the lignocellulosic feedstock (solid BSG) was used to optimize fermentations with Cellulomonas uda. Under aerobic conditions, maximum cellulase activities of 0.98 nkat∙mL−1, maximum xylanase activities of 5.00 nkat∙mL−1 and cell yields of 0.22 gCells∙gBSG−1 were achieved. Under anaerobic conditions, enzyme activities and cell yields were lower, but valuable liquid products (organic acids, ethanol) were produced with a yield of 0.41 gProd∙gBSG−1. The growth phase of the organisms was monitored by measuring extracellular concentrations of two fluorophores pyridoxin (aerobic) and tryptophan (anaerobic) and by cell count. By combining reductive with anaerobic conditions, the ratio of ethanol to acetate was increased from 1.08 to 1.59 molEtOH∙molAc−1. This ratio was further improved to 9.2 molEtOH∙molAc−1 by lowering the pH from 7.4 to 5.0 without decreasing the final ethanol concentration. A fermentation in a bioreactor with 15 w% BSG instead of 5 w% BSG quadrupled the acetate concentration, whilst ethanol was removed by gas stripping. This study provides various ideas for optimizing and monitoring fermentations with solid substrates, which can support feasibility and incorporation into holistic biorefining approaches in the future.
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Affiliation(s)
- Alexander Akermann
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Jens Weiermüller
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | | | - Malte Jakob Nestriepke
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Maria Teresa Baclig
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Roland Ulber
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
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Nothling MD, Cao H, McKenzie TG, Hocking DM, Strugnell RA, Qiao GG. Bacterial Redox Potential Powers Controlled Radical Polymerization. J Am Chem Soc 2021; 143:286-293. [PMID: 33373526 DOI: 10.1021/jacs.0c10673] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Microbes employ a remarkably intricate electron transport system to extract energy from the environment. The respiratory cascade of bacteria culminates in the terminal transfer of electrons onto higher redox potential acceptors in the extracellular space. This general and inducible mechanism of electron efflux during normal bacterial proliferation leads to a characteristic fall in bulk redox potential (Eh), the degree of which is dependent on growth phase, the microbial taxa, and their physiology. Here, we show that the general reducing power of bacteria can be subverted to induce the abiotic production of a carbon-centered radical species for targeted bioorthogonal molecular synthesis. Using two species, Escherichia coli and Salmonella enterica serovar Typhimurium as model microbes, a common redox active aryldiazonium salt is employed to intervene in the terminal respiratory electron flow, affording radical production that is mediated by native redox-active molecular shuttles and active bacterial metabolism. The aryl radicals are harnessed to initiate and sustain a bioorthogonal controlled radical polymerization via reversible addition-fragmentation chain transfer (BacRAFT), yielding a synthetic extracellular matrix of "living" vinyl polymers with predetermined molecular weight and low dispersity. The ability to interface the ubiquitous reducing power of bacteria into synthetic materials design offers a new means for creating engineered living materials with promising adaptive and self-regenerative capabilities.
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Affiliation(s)
- Mitchell D Nothling
- Department of Chemical Engineering, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hanwei Cao
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Thomas G McKenzie
- Department of Chemical Engineering, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Dianna M Hocking
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Richard A Strugnell
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Greg G Qiao
- Department of Chemical Engineering, University of Melbourne, Melbourne, VIC 3010, Australia
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Poladyan A, Blbulyan S, Sahakyan M, Lenz O, Trchounian A. Growth of the facultative chemolithoautotroph Ralstonia eutropha on organic waste materials: growth characteristics, redox regulation and hydrogenase activity. Microb Cell Fact 2019; 18:201. [PMID: 31739794 PMCID: PMC6859627 DOI: 10.1186/s12934-019-1251-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/08/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The chemolithoautotrophic β-proteobacterium Ralstonia eutropha H16 (Cupriavidus necator) is one of the most studied model organisms for growth on H2 and CO2. R. eutropha H16 is also a biologically significant bacterium capable of synthesizing O2-tolerant [NiFe]-hydrogenases (Hyds), which can be used as anode biocatalysts in enzyme fuel cells. For heterotrophic growth of R. eutropha, various sources of organic carbon and energy can be used. RESULTS Growth, bioenergetic properties, and oxidation-reduction potential (ORP) kinetics were investigated during cultivation of R. eutropha H16 on fructose and glycerol or lignocellulose-containing brewery spent grain hydrolysate (BSGH). BSGH was used as carbon and energy source by R. eutropha H16, and the activities of the membrane-bound hydrogenase (MBH) and cytoplasmic, soluble hydrogenase (SH) were measured in different growth phases. Growth of R. eutropha H16 on optimized BSGH medium yielded ~ 0.7 g cell dry weight L-1 with 3.50 ± 0.02 (SH) and 2.3 ± 0.03 (MBH) U (mg protein)-1 activities. Upon growth on fructose and glycerol, a pH drop from 7.0 to 6.7 and a concomitant decrease of ORP was observed. During growth on BSGH, in contrast, the pH and ORP stayed constant. The growth rate was slightly stimulated through addition of 1 mM K3[Fe(CN)6], whereas temporarily reduced growth was observed upon addition of 3 mM dithiothreitol. The overall and N,N'-dicyclohexylcarbodiimide-sensitive ATPase activities of membrane vesicles were ~ 4- and ~ 2.5-fold lower, respectively, upon growth on fructose and glycerol (FGN) compared with only fructose utilization (FN). Compared to FN, ORP was lower upon bacterial growth on FGN, GFN, and BSGH. CONCLUSIONS Our results suggest that reductive conditions and low ATPase activity might be signals for energy depletion, which, in turn, leads to increased hydrogenase biosynthesis to overcome this unfavorable situation. Addition of fructose or microelements have no, or a negative, influence on hydrogenase activity. Organic wastes (glycerol, BSGH) are promising carbon and energy sources for the formation of biomass harboring significant amounts of the biotechnologically relevant hydrogenases MBH and SH. The results are valuable for using microbial cells as producers of hydrogenase enzymes as catalysts in enzymatic fuel cells.
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Affiliation(s)
- Anna Poladyan
- Department of Biochemistry, Microbiology and Biotechnology, Biology Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia
| | - Syuzanna Blbulyan
- Department of Biochemistry, Microbiology and Biotechnology, Biology Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia
| | - Mayramik Sahakyan
- Research Institute of Biology, Biology Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia
| | - Oliver Lenz
- Institute of Chemistry, Technical University of Berlin, 17. Juni 135, 10623, Berlin, Germany
| | - Armen Trchounian
- Department of Biochemistry, Microbiology and Biotechnology, Biology Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia. .,Research Institute of Biology, Biology Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia.
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Olszewska-Widdrat A, Schiro G, Reichel VE, Faivre D. Reducing Conditions Favor Magnetosome Production in Magnetospirillum magneticum AMB-1. Front Microbiol 2019; 10:582. [PMID: 30984131 PMCID: PMC6450187 DOI: 10.3389/fmicb.2019.00582] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 03/07/2019] [Indexed: 01/06/2023] Open
Abstract
Magnetotactic bacteria (MTB) are a heterogeneous group of Gram-negative prokaryotes, which all produce special magnetic organelles called magnetosomes. The magnetosome consists of a magnetic nanoparticle, either magnetite (Fe3O4) or greigite (Fe3S4), embedded in a membrane, which renders the systems colloidaly stable, a desirable property for biotechnological applications. Although these bacteria are able to regulate the formation of magnetosomes through a biologically-controlled mechanism, the environment in general and the physico–chemical conditions surrounding the cells in particular also influence biomineralization. This work thus aims at understanding how such external conditions, in particular the extracellular oxidation reduction potential, influence magnetite formation in the strain Magnetospirillum magneticum AMB-1. Controlled cultivation of the microorganisms was performed at different redox potential in a bioreactor and the formation of magnetosomes was assessed by microscopic and spectroscopic techniques. Our results show that the formation of magnetosomes is inhibited at the highest potential tested (0 mV), whereas biomineralization is facilitated under reduced conditions (-500 mV). This result improves the understanding of the biomineralization process in MTB and provides useful information in sight of a large scale production of magnetosomes for different applications.
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Affiliation(s)
| | - Gabriele Schiro
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany
| | - Victoria E Reichel
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany
| | - Damien Faivre
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany.,Aix-Marseille University, CEA, CNRS, BIAM, Saint-Paul-lés-Durance, France
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Synthesis and antibacterial activity of iron-hexacyanocobaltate nanoparticles. J Biol Inorg Chem 2018; 23:385-398. [PMID: 29478176 DOI: 10.1007/s00775-018-1544-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
This paper deals with the synthesis and characterization of iron-hexacyanocobaltate (FeHCC) and its antibacterial properties. The nanoparticles were prepared by a facile co-precipitation technique. Crystal structure, particle morphology, and elemental composition were determined using X-ray Powder Diffraction, X-ray fluorescence spectroscopy, Transmission Electron Microscopy (TEM), and Infrared Spectroscopy (IR). The antibacterial activity of the FeHCC nanoparticles was tested against Escherichia coli and Staphylococcus aureus as models for Gram-negative and Gram-positive bacteria, respectively, by bacterial counting method and microscopic visualization (TEM, FEG-SEM, and fluorescence microscopy). The results showed that the FeHCC nanoparticles bind to the bacterial cells, inhibit bacterial growth in a dose- and time-dependent manner, inducing a loss of the membrane potential, the production of reactive oxygen species and the release of macromolecules (nucleic acids and proteins) in the extracellular environment. To the best of our knowledge, this is the first study reporting the antimicrobial effects of metal-hexacyanometallates suggesting practical uses of these materials in different areas, such as self-cleaning surfaces or food packaging.
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Hirano SI, Matsumoto N. Electrochemically applied potentials induce growth and metabolic shift changes in the hyperthermophilic bacterium Thermotoga maritima MSB8. Biosci Biotechnol Biochem 2017; 81:1619-1626. [DOI: 10.1080/09168451.2017.1329618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Bioelectrochemical systems are an attractive technology for regulating microbial activity. The effect of an applied potential on hydrolysis of starch in Thermotoga maritima as a model bacterium was investigated in this study. A cathodic potential (−0.6 and −0.8 V) induced 5-h earlier growth initiation of T. maritima with starch as the polymeric substrate than that without electrochemical regulation. Moreover, metabolic patterns of starch consumption were altered by the cathodic potential. While acetate, H2, and CO2 were the major products of starch consumption in the control experiment without electrolysis, lactate accumulation was detected rather than decreased acetate and H2 levels in the bioelectrochemical system experiments with the cathodic potential. These results indicate that the applied potential could control microbial activities related to the hydrolysis of polymeric organic substances and shift carbon and electron flux to a lactate-producing reaction in T. maritima.
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Affiliation(s)
- Shin-ichi Hirano
- Biotechnology Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko-shi, Japan
| | - Norio Matsumoto
- Biotechnology Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko-shi, Japan
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Liato V, Labrie S, Aïder M. Electro-activation of potassium acetate, potassium citrate and calcium lactate: impact on solution acidity, Redox potential, vibrational properties of Raman spectra and antibacterial activity on E. coli O157:H7 at ambient temperature. SPRINGERPLUS 2016; 5:1760. [PMID: 27833832 PMCID: PMC5081071 DOI: 10.1186/s40064-016-3453-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/29/2016] [Indexed: 11/10/2022]
Abstract
AIMS To study the electro-activation of potassium acetate, potassium citrate and calcium lactate aqueous solutions and to evaluate their antimicrobial effect against E. coli O157:H7 at ambient temperature. METHODS AND RESULTS Potassium acetate, potassium citrate and calcium lactate aqueous solutions were electrically excited in the anodic compartment of a four sectional electro-activation reactor. Different properties of the electro-activated solutions were measured such as: solutions acidity (pH and titratable), Redox potential and vibrational properties by Raman spectroscopy. Moreover, the antimicrobial activity of these solutions was evaluated against E. coli O157:H7. The results showed a pH decrease from 7.07 ± 0.08, 7.53 ± 0.12 and 6.18 ± 0.1 down to 2.82 ± 0.1, 2.13 ± 0.09 and 2.26 ± 0.15, after 180 min of electro-activation of potassium acetate, potassium citrate and calcium lactate solution, respectively. These solutions were characterized by high oxidative ORP of +1076 ± 12, +958 ± 11 and +820 ± 14 mV, respectively. Raman scattering analysis of anolytes showed stretching vibrations of the hydrogen bonds with the major changes within the region of 3410-3430 cm-1. These solutions were used against E. coli O157:H7 and the results from antimicrobial assays showed high antibacterial effect with a population reduction of ≥6 log CFU/ml within 5 min of treatment. CONCLUSIONS This study demonstrated the effectiveness of the electro-activation to confer to aqueous solutions of organic salts of highly reactive properties that differ them from their conjugated commercial acids. The electro-activated solutions demonstrated significant antimicrobial activity against E. coli O157:H7. SIGNIFICANCE AND IMPACT OF STUDY This study opens new possibilities to use electro-activated solutions of salts of weak organic acids as food preservatives to develop safe, nutritive and low heat processed foods.
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Affiliation(s)
- Viacheslav Liato
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, QC G1V 0A6 Canada ; Department of Soil Sciences and Agri-Food Engineering, Université Laval, Quebec, QC G1V 0A6 Canada
| | - Steve Labrie
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, QC G1V 0A6 Canada ; Department of Food Sciences, Université Laval, Quebec, QC G1V 0A6 Canada
| | - Mohammed Aïder
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, QC G1V 0A6 Canada ; Department of Soil Sciences and Agri-Food Engineering, Université Laval, Quebec, QC G1V 0A6 Canada ; Laval University, 2425 Rue de l'Agriculture, Pavillon P. Comtois, Quebec, QC G1V 0A6 Canada
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15
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Thomas SC, Alhasawi A, Auger C, Omri A, Appanna VD. The role of formate in combatting oxidative stress. Antonie van Leeuwenhoek 2015; 109:263-71. [PMID: 26626058 DOI: 10.1007/s10482-015-0629-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/28/2015] [Indexed: 01/14/2023]
Abstract
The interaction of keto-acids with reactive oxygen species (ROS) is known to produce the corresponding carboxylic acid with the concomitant formation of CO2. Formate is liberated when the keto-acid glyoxylate neutralizes ROS. Here we report on how formate is involved in combating oxidative stress in the nutritionally-versatile Pseudomonas fluorescens. When the microbe was subjected to hydrogen peroxide (H2O2), the levels of formate were 8 and two-fold higher in the spent fluid and the soluble cell-free extracts obtained in the stressed cultures compared to the controls respectively. Formate was subsequently utilized as a reducing force to generate NADPH and succinate. The former is mediated by formate dehydrogenase (FDH-NADP), whose activity was enhanced in the stressed cells. Fumarate reductase that catalyzes the conversion of fumarate into succinate was also markedly increased in the stressed cells. These enzymes were modulated by H2O2. While the stressed whole cells produced copious amounts of formate in the presence of glycine, the cell-free extracts synthesized ATP and succinate from formate. Although the exact role of formate in anti-oxidative defence has to await further investigation, the data in this report suggest that this carboxylic acid may be a potent reductive force against oxidative stress.
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Affiliation(s)
- Sean C Thomas
- Faculty of Science, Engineering and Architecture, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Azhar Alhasawi
- Faculty of Science, Engineering and Architecture, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Christopher Auger
- Faculty of Science, Engineering and Architecture, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Abdelwahab Omri
- Faculty of Science, Engineering and Architecture, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Vasu D Appanna
- Faculty of Science, Engineering and Architecture, Laurentian University, Sudbury, ON, P3E 2C6, Canada.
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Liato V, Labrie S, Benali M, Aider M. Application of response surface methodology for the optimization of the production of electro-activated solutions in a three-cell reactor. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.eaef.2015.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Ghazaryan A, Blbulyan S, Poladyan A, Trchounian A. Redox stress in geobacilli from geothermal springs: Phenomenon and membrane-associated response mechanisms. Bioelectrochemistry 2015; 105:1-6. [DOI: 10.1016/j.bioelechem.2015.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 04/08/2015] [Indexed: 10/23/2022]
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18
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Vardanyan Z, Trchounian A. Cu(II), Fe(III) and Mn(II) combinations as environmental stress factors have distinguishing effects on Enterococcus hirae. J Environ Sci (China) 2015; 28:95-100. [PMID: 25662243 DOI: 10.1016/j.jes.2014.06.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 06/04/2023]
Abstract
Pollution by various heavy metals as environmental stress factors might affect bacteria. It was established that iron (Fe(III)), manganese (Mn(II)) and copper (Cu(II)) ion combinations caused effects on Enterococcus hirae that differed from the sum of the effects when the metals were added separately. It was shown that the Cu2+-Fe3+ combination decreased the growth and ATPase activity of membrane vesicles of wild-type E. hirae ATCC9790 and atpD mutant (with defective FoF1-ATPase) MS116. Addition of Mn2+-Fe3+ combinations within the same concentration range had no effects on growth compared to control (without heavy metals). ATPase activity was increased in the presence of Mn2+-Fe3+, while together with 0.2 mmol/L N,N'-dicyclohexylcarbodiimide (DCCD), ATPase activity was decreased compared to control (when only 0.2 mmol/L DCCD was present). These results indicate that heavy metals ion combinations probably affect the FOF1-ATPase, leading to conformational changes. Moreover the action may be direct or be mediated by environment redox potential. The effects observed when Fe3+ was added separately disappeared in both cases, which might be a result of competing processes between Fe3+ and other heavy metals. These findings are novel and improve the understanding of heavy metals ions effects on bacteria, and could be applied for regulation of stress response patterns in the environment.
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Affiliation(s)
- Zaruhi Vardanyan
- Department of Biophysics, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia.
| | - Armen Trchounian
- Department of Microbiology, Plants and Microbes Biotechnology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia.
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Comparable effects of low-intensity electromagnetic irradiation at the frequency of 51.8 and 53 GHz and antibiotic ceftazidime on Lactobacillus acidophilus growth and survival. Cell Biochem Biophys 2014; 67:829-35. [PMID: 23516095 DOI: 10.1007/s12013-013-9571-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of low-intensity electromagnetic irradiation (EMI) with the frequencies of 51.8 and 53 GHz on Lactobacillus acidophilus growth and survival were revealed. These effects were compared with antibacterial effects of antibiotic ceftazidime. Decrease in bacterial growth rate by EMI was comparable with the inhibitory effect of ceftazidime (minimal inhibitory concentration-16 μM) and no enhanced action was observed with combined effects of EMI and the antibiotic. However, EMI-enhanced antibiotic inhibitory effect on bacterial survival. The kinetics of the bacterial suspension oxidation-reduction potential up to 24 h of the growth was changed by EMI and ceftazidime. The changes were more strongly expressed by combined effects of EMI and antibiotic especially up to 12 h. Moreover, EMI did not change overall energy (glucose)-dependent H(+) efflux across the membrane but it increased N,N'-dicyclohexylcarbodiimide (DCCD)-inhibited H(+) efflux. In contrast, this EMI in combination with ceftazidime decreased DCCD-sensitive H(+) efflux. Low-intensity EMI had inhibitory effect on L. acidophilus bacterial growth and survival. The effect on bacterial survival was more significant in the combination with ceftazidime. The H(+)-translocating F 0 F 1-ATPase, for which DCCD is specific inhibitor, might be a target for EMI and ceftazidime. The revealed bactericide effects on L. acidophilus can be applied in biotechnology, food producing and safety technology.
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Poladyan A, Trchounian K, Sawers RG, Trchounian A. Hydrogen-oxidizing hydrogenases 1 and 2 ofEscherichia coliregulate the onset of hydrogen evolution and ATPase activity, respectively, during glucose fermentation at alkaline pH. FEMS Microbiol Lett 2013; 348:143-8. [DOI: 10.1111/1574-6968.12281] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/17/2013] [Indexed: 11/29/2022] Open
Affiliation(s)
- Anna Poladyan
- Department of Microbiology, Plants and Microbes Biotechnology; Faculty of Biology; Yerevan State University; Yerevan Armenia
| | - Karen Trchounian
- Department of Biophysics; Faculty of Biology; Yerevan State University; Yerevan Armenia
- Institute of Biology/Microbiology; Martin Luther University of Halle-Wittenberg; Halle Germany
| | - R. Gary Sawers
- Institute of Biology/Microbiology; Martin Luther University of Halle-Wittenberg; Halle Germany
| | - Armen Trchounian
- Department of Microbiology, Plants and Microbes Biotechnology; Faculty of Biology; Yerevan State University; Yerevan Armenia
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Lin J, Xu Y, Brookes PC, He Y, Xu J. Spatial and temporal variations in pentachlorophenol dissipation at the aerobic--anaerobic interfaces of flooded paddy soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 178:433-440. [PMID: 23628887 DOI: 10.1016/j.envpol.2013.03.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
Pentachlorophenol (PCP) dissipation occurs naturally in flooded soils and although dissipation half-lives vary between soil profiles at the millimeter-scale the reason is poorly understood. Vertical variations of PCP dissipation were investigated in three typical Chinese paddy soils; Soil 1 (Umbraqualf), Soil 2 (Plinthudult) and Soil 3 (Tropudult). The soil depth was divided into a surface and a deep layer based upon different PCP dissipations in the surface layer of 40-93, 42-88 and 16-100% for Soils 1-3 respectively. In the deep layer, PCP was greatly dissipated in Soil 2, but much less in Soil 1 and Soil 3. Correlation analysis indicated that SO4(2-) and Fe(III) were negatively related to PCP dissipation. SO4(2-) and Cl(-) were highly mobile in the flooded soil profiles. Fe(III) reduction increased with increasing soil depth, and was inhibited by high SO4(2-) concentrations.
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Affiliation(s)
- Jiajiang Lin
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058, China
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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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23
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Hirano S, Matsumoto N, Morita M, Sasaki K, Ohmura N. Electrochemical control of redox potential affects methanogenesis of the hydrogenotrophic methanogen Methanothermobacter thermautotrophicus. Lett Appl Microbiol 2013; 56:315-21. [PMID: 23413966 DOI: 10.1111/lam.12059] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 02/04/2023]
Abstract
To investigate the precise effect of the redox potential on the methanogenesis of the hydrogenotrophic methanogen Methanothermobacter thermautotrophicus by using an electrochemical redox controlling system without adding oxidizing or reducing agents. A bioelectrochemical system was applied to control the redox conditions in culture and to measure the methane-producing activity of M. thermautotrophicus at a constant potential from +0·2 to -0·8 V (vs Ag/AgCl). Methane production and growth of M. thermautotrophicus were 1·6 and 3·5 times increased at -0·8 V, compared with control experiments without electrolysis, respectively, while methanogenesis was suppressed between +0·2 and -0·2 V. A clear relationship between an electrochemically regulated redox potential and methanogenesis was revealed.
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Affiliation(s)
- S Hirano
- Biotechnology Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko, Japan.
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24
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Ignatova M, Guével B, Com E, Haddad N, Rossero A, Bogard P, Prévost H, Guillou S. Two-dimensional fluorescence difference gel electrophoresis analysis of Listeria monocytogenes submitted to a redox shock. J Proteomics 2013. [DOI: 10.1016/j.jprot.2012.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Liu CG, Xue C, Lin YH, Bai FW. Redox potential control and applications in microaerobic and anaerobic fermentations. Biotechnol Adv 2012. [PMID: 23178703 DOI: 10.1016/j.biotechadv.2012.11.005] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Many fermentation products are produced under microaerobic or anaerobic conditions, in which oxygen is undetectable by dissolved oxygen probe, presenting a challenge for process monitoring and control. Extracellular redox potentials that can be detected conveniently affect intracellular redox homeostasis and metabolism, and consequently control profiles of fermentation products, which provide an alternative for monitoring and control of these fermentation processes. This article reviews updated progress in the impact of redox potentials on gene expression, protein biosynthesis and metabolism as well as redox potential control strategies for more efficient production of fermentation products, taking ethanol fermentation by the yeast Saccharomyces under microaerobic conditions and butanol production by the bacterium Clostridium under anaerobic conditions as examples.
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Affiliation(s)
- Chen-Guang Liu
- School of Life Sciences and Biotechnology, Dalian University of Technology, Dalian 116023, China
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Lin J, He Y, Xu J. Changing redox potential by controlling soil moisture and addition of inorganic oxidants to dissipate pentachlorophenol in different soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2012; 170:260-267. [PMID: 22842055 DOI: 10.1016/j.envpol.2012.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 06/29/2012] [Accepted: 07/01/2012] [Indexed: 06/01/2023]
Abstract
The potential for dissipation of pentachlorophenol (PCP) was investigated in soils from four different sites in China. These were an umbraqualf (Soil 1), a Plinthudult (Soil 2), a Haplustalf (Soil 3) and an Argiustoll (Soil 4) which were either flooded, to produce anaerobic conditions, or incubated aerobically at 60% water-holding capacity (WHC). The dissipation of PCP in Soil 1 at 60% WHC was higher than under flooded condition, while the opposite occurred in the other three soils. Under flooded conditions, the redox potential decreased significantly in Soil 1 and Soil 4, where sulphate reduction was occurred and the dissipation of PCP was statistically significant (about 96% and 98%, respectively) at the end of incubation. After addition of inorganic oxidants, dissipation of PCP was significantly inhibited by FeCl(3), while Na(2)SO(4) and NaNO(3) had different effects, depending upon the soil type.
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Affiliation(s)
- Jiajiang Lin
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058, China
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Poladyan A, Avagyan A, Vassilian A, Trchounian A. Oxidative and Reductive Routes of Glycerol and Glucose Fermentation by Escherichia coli Batch Cultures and Their Regulation by Oxidizing and Reducing Reagents at Different pHs. Curr Microbiol 2012; 66:49-55. [DOI: 10.1007/s00284-012-0240-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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28
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A novel protein Jpk induces bacterial cell death through reactive oxygen species. Gene 2012; 504:274-8. [PMID: 22652273 DOI: 10.1016/j.gene.2012.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 05/03/2012] [Accepted: 05/10/2012] [Indexed: 11/22/2022]
Abstract
Jpk, a trans-acting regulatory factor associating with the position-specific regulatory element of Hoxa-7, has been reported to induce cell death in both prokaryotic and eukaryotic cells upon overexpression. The N- and C-terminal deleted variants of Jpk were constructed and then the toxicity of each construct was analyzed by checking the viability of the cells and the concomitant morphological changes through electron microscopy following the expression. The N-terminus of Jpk harboring transmembrane domain seemed to be more toxic to bacterial cell than C-terminus and the morphology of bacterial cells expressing N-terminal Jpk was similar to that induced by full length Jpk. The toxicity caused by Jpk protein in bacterial cell was through the production of ROS, which was decreased by an antioxidant (DTT) in a concentration dependent manner. The finding described in this study provides valuable clues on the relationship between Jpk toxicity and ROS generation.
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Vardanyan Z, Trchounian A. Fe(III) and Fe(II) ions different effects on Enterococcus hirae cell growth and membrane-associated ATPase activity. Biochem Biophys Res Commun 2011; 417:541-5. [PMID: 22166211 DOI: 10.1016/j.bbrc.2011.11.159] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 11/30/2011] [Indexed: 11/16/2022]
Abstract
Enterococcus hirae is able to grow under anaerobic conditions during glucose fermentation (pH 8.0) which is accompanied by acidification of the medium and drop in its oxidation-reduction potential (E(h)) from positive values to negative ones (down to ∼-200 mV). In this study, iron (III) ions (Fe(3+)) have been shown to affect bacterial growth in a concentration-dependent manner (within the range of 0.05-2 mM) by decreasing lag phase duration and increasing specific growth rate. While iron(II) ions (Fe(2+)) had opposite effects which were reflected by suppressing bacterial growth. These ions also affected the changes in E(h) values during bacterial growth. It was revealed that ATPase activity with and without N,N'-dicyclohexylcarbodiimide (DCCD), an inhibitor of the F(0)F(1)-ATPase, increased in the presence of even low Fe(3+) concentration (0.05 mM) but decreased in the presence of Fe(2+). It was established that Fe(3+) and Fe(2+) both significantly inhibited the proton-potassium exchange of bacteria, but stronger effects were in the case of Fe(2+) with DCCD. Such results were observed with both wild-type ATCC9790 and atpD mutant (with defective F(0)F(1)) MS116 strains but they were different with Fe(3+) and Fe(2+). It is suggested that the effects of Fe(3+) might be due to interaction of these ions with F(0)F(1) or there might be a Fe(3+)-dependent ATPase different from F(0)F(1) in these bacteria that is active even in the presence of DCCD. Fe(2+) inhibits E. hirae cell growth probably by strong effect on E(h) leading to changes in F(0)F(1) and decreasing its activity.
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Affiliation(s)
- Zaruhi Vardanyan
- Department of Biophysics of the Biology Faculty, Yerevan State University, Yerevan, Armenia
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Soghomonyan D, Akopyan K, Trchounian A. pH and oxidation-reduction potential change of environment during growth of lactic acid bacteria: Effects of oxidizers and reducers. APPL BIOCHEM MICRO+ 2011. [DOI: 10.1134/s0003683811010157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vardanyan Z, Trchounian A. The effects of copper (II) ions on Enterococcus hirae cell growth and the proton-translocating FoF1 ATPase activity. Cell Biochem Biophys 2010; 57:19-26. [PMID: 20352375 DOI: 10.1007/s12013-010-9078-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Enterococcus hirae grow well under anaerobic conditions at alkaline pH (pH 8.0) producing acids by glucose fermentation. Bacterial growth was shown to be accompanied by decrease of redox potential from positive values (approximately +35 mV) to negative ones (approximately -220 mV). An oxidizer copper (II) ions (Cu(2+)) affected bacterial growth in a concentration-dependent manner (within the range of 0.05 mM to 1 mM) increasing lag phase duration and decreasing specific growth rate. These effects were observed with the wild-type strain ATCC9790 and the atpD mutant strain MS116 (with absent beta subunit of F(1) of the F(o)F(1) ATPase) both. Also ATPase activity and proton-potassium ions exchange were assessed with and without N,N'-dicyclohexylcarbodiimide (DCCD), inhibitor of the F(o)F(1) ATPase. In both cases (DCCD +/-), even low Cu(2+) concentrations had noticeable effect on ATPase activity, but with less visible concentration-dependent manner. Changes in the number of accessible SH-groups were observed with E. hirae ATCC9790 and MS116 membrane vesicles. In both strains Cu(2+) markedly decreased the number of SH-groups in the presence of K(+) ions. The addition of ATP increased the amount of accessible SH-groups in ATCC9790 and decreased this number in MS116; Cu(2+) blocked ATP-installed increase in SH-groups number in ATCC9790. H(+)-K(+)-exchange of bacteria was markedly inhibited by Cu(2+), but stronger effects were detected together with DCCD. Moreover, discrimination between Cu(2+) and other bivalent cation--Ni(2+) was shown. It is suggested that Cu(2+) ions inhibit E. hirae cell growth by direct affect on the F(o)F(1) ATPase leading to conformational changes in this protein complex and decrease in its activity.
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Affiliation(s)
- Zaruhi Vardanyan
- Department of Biophysics of the Biological Faculty, Yerevan State University, 1 A. Manoukian Str, 0025, Yerevan, Armenia
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Lin YH, Chien WS, Duan KJ. Correlations between reduction–oxidation potential profiles and growth patterns of Saccharomyces cerevisiae during very-high-gravity fermentation. Process Biochem 2010. [DOI: 10.1016/j.procbio.2010.01.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Xie XH, Li EL, Tang ZK. Real-time monitoring of induced adaptation of redox active Escherichia coli biofilm by EQCM-controlled extracellular redox environment. Electrochem commun 2010. [DOI: 10.1016/j.elecom.2010.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Ignatova M, Prévost H, Leguerinel I, Guillou S. Growth and reducing capacity of Listeria monocytogenes under different initial redox potential. J Appl Microbiol 2010; 108:256-65. [DOI: 10.1111/j.1365-2672.2009.04426.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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35
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Santiago-Gómez MP, Thanh HT, De Coninck J, Cachon R, Kermasha S, Belin JM, Gervais P, Husson F. Modeling hexanal production in oxido-reducing conditions by the yeast Yarrowia lipolytica. Process Biochem 2009. [DOI: 10.1016/j.procbio.2009.04.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ignatova M, Leguerinel I, Guilbot M, Prévost H, Guillou S. Modelling the effect of the redox potential and pH of heating media onListeria monocytogenesheat resistance. J Appl Microbiol 2008; 105:875-83. [DOI: 10.1111/j.1365-2672.2008.03812.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pham TH, Mauvais G, Vergoignan C, De Coninck J, Dumont F, Lherminier J, Cachon R, Feron G. Gaseous environments modify physiology in the brewing yeastSaccharomyces cerevisiaeduring batch alcoholic fermentation. J Appl Microbiol 2008; 105:858-74. [DOI: 10.1111/j.1365-2672.2008.03821.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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38
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Copper (II) ions affect Escherichia coli membrane vesicles' SH-groups and a disulfide-dithiol interchange between membrane proteins. Cell Biochem Biophys 2008; 51:45-50. [PMID: 18458828 DOI: 10.1007/s12013-008-9014-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2007] [Accepted: 04/21/2008] [Indexed: 11/27/2022]
Abstract
The SH-groups in Escherichia coli membrane vesicles, prepared from cells grown in fermentation conditions on glucose at slightly alkaline pH, have a role in the F0F1-ATPase operation. The changes in the number of these groups by ATP are observed under certain conditions. In this study, copper ions (Cu2+) in concentration of 0.1 mM were shown to increase the number of SH-groups in 1.5- to 1.6-fold independent from K+ ions, and the suppression of the increased level of SH-groups by ATP was determined for Cu2+ in the presence of K+. Moreover, the increase in the number of SH-groups by Cu2+ was absent as well as the inhibition in ATP-dependent increasing SH-groups number by Cu2+ lacked when vesicles were treated with N-ethylmaleimide (NEM), specific thiol-reagent. Such an effect was not observed with zinc (Zn2+), cobalt (Co2+), or Cu+ ions. The increased level of SH-groups was observed in the hycE or hyfR mutants with defects in hydrogenases 3 or 4, whereas the ATP-dependent increase in the number of these groups was determined in hycE not in hyfR mutants. Both changes in SH-groups number disappeared in the atp or hyc mutants deleted for the F0F1-ATPase or hydrogenase 3 (no activity of hydrogenase 4 was detected in the hyc mutant used). A direct effect of Cu2+ but not Cu+ on the F0F1-ATPase is suggested to lead to conformational changes or damaging consequences, increasing accessible SH-groups number and disturbing disulfide-dithiol interchange within a protein-protein complex, where this ATPase works with K+ uptake system or hydrogenase 4 (Hyd-4); breaks in disulfides are not ruled out.
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Stepanyan K, Balayan M, Vassilian A, Pepoyan A, Trchounian A. Some growth peculiarities and membrane characteristics of probiotic strains of Escherichia coli. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2007. [DOI: 10.1134/s1990747807040095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kirakosyan G, Trchounian A. Redox sensing by Escherichia coli: Effects of copper ions as oxidizers on proton-coupled membrane transport. Bioelectrochemistry 2007; 70:58-63. [PMID: 16713752 DOI: 10.1016/j.bioelechem.2006.03.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2005] [Indexed: 11/19/2022]
Abstract
Escherichia coli is able to grow under anaerobic fermentation conditions upon a decrease in redox potential (E(h)). Indeed, upon a transition of E. coli MC4100 wild-type culture to stationary growth phase a decrease in E(h) from the positive values ( approximately +100 mV) to the negative ones ( approximately -520 mV) was observed, the acidification of the medium and the H(2) production were obtained. An oxidizer, copper ions (Cu(2+)) affected a bacterial growth in a concentration-dependent manner (of 0.1 mM to 10 mM) increasing latent (lag) growth phase duration, delaying logarithmic (log) growth phase and decreasing specific growth rate. Acidification of the medium and the N,N'-dicyclohexylcarbodiimide (DCCD)- and azide-sensitive proton-potassium exchange by bacteria were inhibited, H(2) production upon growth and under assays disappeared with Cu(2+) (0.1 mM). These effects were observed with hycE but not hyfR and hyc(A-H) mutants and under aerobic conditions. Cu(2+) also increased membrane proton conductance. Copper ions are suggested to affect directly the F(0)F(1)-ATPase associated with potassium uptake transport system and/or formate hydrogenlyase composed with hydrogenase 4. A role of the F(0)F(1)-ATPase in redox sensing under fermentation is proposed.
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Affiliation(s)
- Gayane Kirakosyan
- Department of Biophysics, Biological Faculty, Yerevan State University, 1 Alex Manoukian Str., 375025 Yerevan, Armenia
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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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42
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Krzepiłko A, Swieciło A, Wawryn J, Zadrag R, Kozioł S, Bartosz G, Biliński T. Ascorbate restores lifespan of superoxide-dismutase deficient yeast. Free Radic Res 2005; 38:1019-24. [PMID: 15621721 DOI: 10.1080/10715760410001717327] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Yeast (Saccharomyces cerevisiae) mutants lacking CuZn-superoxide dismutase (CuZnSOD) are hypersensitive to oxygen and have significantly decreased replicative life span. Both these defects can be ameliorated by exogenous ascorbate. The effect of ascorbate on life span is complicated by auto-oxidation of its compound in the medium. If negative effects of auto-oxidation are prevented by exchange of the medium, ascorbate prolongs not only mean but also maximal replicative life span of the yeast in the atmosphere of air and of pure oxygen. These results demonstrate that life span shortening due to the lack of a vital antioxidant enzyme can be ameliorated by a low-molecular weight antioxidant.
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Affiliation(s)
- Anna Krzepiłko
- Zamość College of Agriculture, ul. Szczebrzeska 102, PL 22-400 Zamość, Poland
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Kirakosyan G, Bagramyan K, Trchounian A. Redox sensing by Escherichia coli: effects of dithiothreitol, a redox reagent reducing disulphides, on bacterial growth. Biochem Biophys Res Commun 2005; 325:803-6. [PMID: 15541361 DOI: 10.1016/j.bbrc.2004.10.119] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Indexed: 11/20/2022]
Abstract
Escherichia coli is able to grow with a high rate under anaerobic conditions upon decrease in redox potential (E(h)) both either in slightly alkaline (pH 7.5) or acidic (pH 5.5) medium. Upon transition of E. coli MC4100 culture to stationary growth phase a decrease in E(h) from the positive values of +120 to +160 mV to the negative ones of -380 to -550 mV, and the H(2) production are observed at various pH. A redox reagent dl-dithiothreitol (DTT) in a concentration of 3mM reduces E(h) to the negative values, and increases a latent (lag) growth phase duration, as well as delays a logarithmic growth phase independently of pH. At alkaline and acidic pH the changes in membrane potential (DeltaPsi) are observed in the presence of 3mM DTT. K(+) uptake is recovered. At pH 5.5 the H(2) production is suppressed by DTT only in a higher concentration of 10 mM. The results suggest DTT effects that are in addition to the effects of E(h). The mechanism of DTT action on bacterial growth might be intermediated through thiol group modulation of the membrane proteins, which is reflected as the generation of DeltaPsi as well as K(+) accumulation and the activity of the membrane-associated enzymes.
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Affiliation(s)
- Gayane Kirakosyan
- Department of Biophysics, Yerevan State University, 1 Alex Manoukian Str., Yerevan 375025, Armenia
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Waché Y, Riondet C, Diviès C, Cachon R. Effect of reducing agents on the acidification capacity and the proton motive force of Lactococcus lactis ssp. cremoris resting cells. Bioelectrochemistry 2002; 57:113-8. [PMID: 12160606 DOI: 10.1016/s1567-5394(02)00051-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Reducing agents are potential inhibitors of the microbial growth. We have shown recently that dithiothreitol (DTT), NaBH(4) and H(2) can modify the proton motive force of resting cells of Escherichia coli by increasing the membrane protons permeability [Eur. J. Biochem. 262 (1999) 595]. In the present work, the effect of reducing agents on the resting cells of Lactococcus lactis ssp. cremoris, a species widely employed in dairy processes was investigated. DTT did not affect the acidification nor the DeltapH, in contrast to the effect previously reported on E. coli. The DeltaPsi was slightly increased (30 mV) at low pH (pH 4) in the presence of 31 mM DTT or 2.6 mM NaBH(4). In the case of Na(2)S(2)O(4), small amounts (0.9 mM) drastically decreased the acidification range and this product was shown to abolish the DeltapH. These results are discussed in terms of the diversity of action of the chemical reagents and strain sensitivity.
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Affiliation(s)
- Yves Waché
- Laboratoire de Microbiologie de l'ENSBANA (UMR INRA-Université de Bourgogne), 1, esplanade Erasme, 21000 Dijon, France.
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