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Purohit A, Pawar L, Yadav SK. Fermenter scale production of recombinant beta-mannanase by E. coli BL21 cells under microaerobic environment. Carbohydr Res 2024; 541:109150. [PMID: 38788560 DOI: 10.1016/j.carres.2024.109150] [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: 03/23/2024] [Revised: 04/29/2024] [Accepted: 05/18/2024] [Indexed: 05/26/2024]
Abstract
Aim of the study was to optimize and produce beta-mannanase at fermenter scale by using cheaper minimal media. Increased production of beta-mannanase from Microbacterium camelliasinensis CIAB417 was achieved by heterologous expression in E. coli BL21 (DE3). The scale-up production of beta-mannanase was optimized from shake flask to 5-L fermenter. The cost-effective minimal media (M9+e) without any vitamins was found to be most effective and optimized for culturing the cells. The same media displayed no significant fluctuation in the pH while culturing the cells for the production of beta-mannanase both at shake flask and fermenter level. Additionally, E. coli cells were able to produce similar amount of dry cell weight and recombinant beta-mannanase both in the presence of micro and macro-oxygen environment. The optimized media was demonstrated to show no significant drop in pH throughout the recombinant protein production process. In one litre medium, 2.0314 g dry weight of E. coli cells yielded 1.8 g of purified recombinant beta-mannanase. The purified enzyme was lyophilized and demonstrated to hydrolyse locust bean gum to release mannooligosaccharides.
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Affiliation(s)
- Anjali Purohit
- Center of Innovative and Applied Bioprocessing (CIAB), Sector-81, Knowledge City, Mohali, 140306, India
| | - Lata Pawar
- Center of Innovative and Applied Bioprocessing (CIAB), Sector-81, Knowledge City, Mohali, 140306, India
| | - Sudesh Kumar Yadav
- Center of Innovative and Applied Bioprocessing (CIAB), Sector-81, Knowledge City, Mohali, 140306, India; CSIR-Institute of Himalayan Bioresource Technology, Palampur, 176061, (HP), India.
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2
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Sørensen HV, Montserrat-Canals M, Loose JSM, Fisher SZ, Moulin M, Blakeley MP, Cordara G, Bjerregaard-Andersen K, Krengel U. Perdeuterated GbpA Enables Neutron Scattering Experiments of a Lytic Polysaccharide Monooxygenase. ACS OMEGA 2023; 8:29101-29112. [PMID: 37599915 PMCID: PMC10433351 DOI: 10.1021/acsomega.3c02168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/14/2023] [Indexed: 08/22/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are surface-active redox enzymes that catalyze the degradation of recalcitrant polysaccharides, making them important tools for energy production from renewable sources. In addition, LPMOs are important virulence factors for fungi, bacteria, and viruses. However, many knowledge gaps still exist regarding their catalytic mechanism and interaction with their insoluble, crystalline substrates. Moreover, conventional structural biology techniques, such as X-ray crystallography, usually do not reveal the protonation state of catalytically important residues. In contrast, neutron crystallography is highly suited to obtain this information, albeit with significant sample volume requirements and challenges associated with hydrogen's large incoherent scattering signal. We set out to demonstrate the feasibility of neutron-based techniques for LPMOs using N-acetylglucosamine-binding protein A (GbpA) from Vibrio cholerae as a target. GbpA is a multifunctional protein that is secreted by the bacteria to colonize and degrade chitin. We developed an efficient deuteration protocol, which yields >10 mg of pure 97% deuterated protein per liter expression media, which was scaled up further at international facilities. The deuterated protein retains its catalytic activity and structure, as demonstrated by small-angle X-ray and neutron scattering studies of full-length GbpA and X-ray crystal structures of its LPMO domain (to 1.1 Å resolution), setting the stage for neutron scattering experiments with its substrate chitin.
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Affiliation(s)
- H. V. Sørensen
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | - Mateu Montserrat-Canals
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
- Centre
for Molecular Medicine Norway, University
of Oslo, NO-0318 Oslo, Norway
| | - Jennifer S. M. Loose
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), NO-1340 Ås, Norway
| | - S. Zoë Fisher
- Science
Directorate, European Spallation Source
ERIC, P.O. Box 176, SE-221 00 Lund, Sweden
- Department
of Biology, Lund University, 35 Sölvegatan, SE-223 62 Lund, Sweden
| | - Martine Moulin
- Life Sciences
Group, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Cedex 9 Grenoble, France
| | - Matthew P. Blakeley
- Large-Scale
Structures Group, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Gabriele Cordara
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | | | - Ute Krengel
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
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3
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Varner TA, Mohamed-Raseek N, Miller AF. Assignments of 19F NMR resonances and exploration of dynamics in a long-chain flavodoxin. Arch Biochem Biophys 2021; 703:108839. [PMID: 33727041 DOI: 10.1016/j.abb.2021.108839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 12/23/2022]
Abstract
Flavodoxin is a small protein that employs a non-covalently bound flavin to mediate single-electron transfer at low potentials. The long-chain flavodoxins possess a long surface loop that is proposed to interact with partner proteins. We have incorporated 19F-labeled tyrosine in long-chain flavodoxin from Rhodopseudomonas palustris to gain a probe of possible loop dynamics, exploiting the presence of a Tyr in the long loop in addition to Tyr residues near the flavin. We report 19F resonance assignments for all four Tyrs, and demonstration of a pair of resonances in slow exchange, both corresponding to a Tyr adjacent to the flavin. We also provide evidence for dynamics affecting the Tyr in the long loop. Thus, we show that 19F NMR of 19F-Tyr labeled flavodoxin holds promise for monitoring possible changes in conformation upon binding to partner proteins.
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Affiliation(s)
- Taylor A Varner
- Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA
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4
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A novel approach for production of an active N-terminally truncated Ulp1 (SUMO protease 1) catalytic domain from Escherichia coli inclusion bodies. Protein Expr Purif 2020; 166:105507. [DOI: 10.1016/j.pep.2019.105507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/23/2019] [Accepted: 10/02/2019] [Indexed: 01/21/2023]
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5
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Cai M, Huang Y, Craigie R, Clore GM. A simple protocol for expression of isotope-labeled proteins in Escherichia coli grown in shaker flasks at high cell density. JOURNAL OF BIOMOLECULAR NMR 2019; 73:743-748. [PMID: 31677040 DOI: 10.1007/s10858-019-00285-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Protein expression in E. coli grown in shaker flasks is a routine and pivotal tool in many research laboratories. To maximize protein yields, cells are normally induced in the middle of the linear growth phase, typically at an OD600 of ≤ 1 for cells grown in Luria-Bertani (LB) medium at 37 °C. We recently showed that the E. coli linear growth phase can be extended to higher cell density when cells are cultured under less than optimal conditions such as in minimal medium and/or at lower temperatures. Maximizing the yield of protein per unit volume of culture is important for reducing the costs, especially when isotopically labeling is required. Here, we present a modified minimal medium and a simple protocol that can increase the protein yield up to fourfold in a pH-stabilized LB medium and up to sevenfold in a modified M9+ medium (M9++). When M9++ medium coupled with the high density (OD600 ~ 6) cell growth protocol are used to express uniformly 15N- or 15N/13C-labeled proteins, the amount of 15NH4Cl and 13C6-glucose for a given cell mass is reduced by 50% and ~ 65%, respectively, relative to the traditional low density (OD600 ~ 1) cell growth protocol with M9 medium; the inclusion of 0.1% LB in the minimal medium permits a reduction in the concentration of both the trace element solution and MgCl2, which can cause precipitation. Mass data indicate that inclusion of 0.1% LB does not significantly affect the isotope enrichment level.
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Affiliation(s)
- Mengli Cai
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Ying Huang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
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6
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Azatian SB, Kaur N, Latham MP. Increasing the buffering capacity of minimal media leads to higher protein yield. JOURNAL OF BIOMOLECULAR NMR 2019; 73:11-17. [PMID: 30613903 PMCID: PMC6441617 DOI: 10.1007/s10858-018-00222-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/22/2018] [Indexed: 05/03/2023]
Abstract
We describe a general and simple modification to the standard M9 minimal medium recipe that leads to an approximate twofold increase in the yield of heterologously expressed proteins in Escherichia coli BL21(DE3) bacteria. We monitored the growth of bacteria transformed with plasmids for three different test proteins in five minimal media with different concentrations of buffering salts and/or initial media pH. After purification of the over-expressed proteins, we found a clear correlation between the protein yield and change in media pH over time, where the minimal media that were the most buffered and therefore most resistant to change in pH produced the most protein. And in all three test protein cases, the difference in yield was nearly twofold between the best and worst buffering media. Thus, we propose that increasing the buffering capacity of M9 minimal media will generally lead to a similar increase for most of the proteins currently produced by this standard protein expression protocol. Moreover, we have qualitatively found that this effect also extends to deuterated M9 minimal media growths, which could lead to significant cost savings in these preparations.
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Affiliation(s)
- Stephan B Azatian
- Department of Chemistry and Biochemistry, Texas Tech University, 1204 Boston Ave., Lubbock, TX, 79423-1061, USA
| | - Navneet Kaur
- Department of Chemistry and Biochemistry, Texas Tech University, 1204 Boston Ave., Lubbock, TX, 79423-1061, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, 1204 Boston Ave., Lubbock, TX, 79423-1061, USA.
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7
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McCaig R, Morrison M. Characterization of Enterobacter Agglomerans Variants and Their Importance in Brewing. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-42-0023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Robert McCaig
- Molson Breweries of Canada Limited, Montreal, Quebec, Canada, H2L 2R5
| | - Margaret Morrison
- Molson Breweries of Canada Limited, Montreal, Quebec, Canada, H2L 2R5
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8
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Cai M, Huang Y, Yang R, Craigie R, Clore GM. A simple and robust protocol for high-yield expression of perdeuterated proteins in Escherichia coli grown in shaker flasks. JOURNAL OF BIOMOLECULAR NMR 2016; 66:85-91. [PMID: 27709314 PMCID: PMC5866134 DOI: 10.1007/s10858-016-0052-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/05/2016] [Indexed: 05/03/2023]
Abstract
We present a simple, convenient and robust protocol for expressing perdeuterated proteins in E. coli BL21(DE3) cells in shaker flasks that reduces D2O usage tenfold and d7-glucose usage by 30 %. Using a modified M9 medium and optimized growth conditions, we were able to grow cells in linear log phase to an OD600 of up to 10. Inducing the cells with isopropyl β-D-1-thiogalactopyranoside at an OD600 of 10, instead of less than 1, enabled us to increase the cell mass tenfold per unit volume of cell culture. We show that protein expression levels per cell are the same when induced at an OD600 between 1 and 10 under these growth conditions. Thus, our new protocol can increase protein yield per unit volume of cell culture tenfold. Adaptation of E. coli from H2O-based to D2O-based medium is also key for ensuring high levels of protein expression in D2O. We find that a simple three-step adaptation approach-Luria-Bertani (LB) medium in H2O to LB in D2O to modified-M9 medium in D2O is both simple and reliable. The method increases the yield of perdeuterated proteins by up to tenfold using commonly available air shakers without any requirement for specialized fermentation equipment.
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Affiliation(s)
- Mengli Cai
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Ying Huang
- Laboratories of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Renbin Yang
- Laboratories of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Robert Craigie
- Laboratories of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - G M Clore
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
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9
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Robust High-Yield Methodologies for 2H and 2H/15N/13C Labeling of Proteins for Structural Investigations Using Neutron Scattering and NMR. Methods Enzymol 2015; 565:3-25. [DOI: 10.1016/bs.mie.2015.06.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Chingin K, Liang J, Hang Y, Hu L, Chen H. Rapid recognition of bacteremia in humans using atmospheric pressure chemical ionization mass spectrometry of volatiles emitted by blood cultures. RSC Adv 2015. [DOI: 10.1039/c4ra16502k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human bacteremia is rapidly diagnosed by direct atmospheric pressure chemical ionization mass spectrometry analysis of blood culture volatiles.
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Affiliation(s)
- Konstantin Chingin
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation
- East China Institute of Technology
- Nanchang 330013
- P.R. China
| | - Juchao Liang
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation
- East China Institute of Technology
- Nanchang 330013
- P.R. China
| | - Yaping Hang
- The Second Affiliated Hospital of Nanchang University
- Nanchang 330006
- P.R China
| | - Longhua Hu
- The Second Affiliated Hospital of Nanchang University
- Nanchang 330006
- P.R China
| | - Huanwen Chen
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation
- East China Institute of Technology
- Nanchang 330013
- P.R. China
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11
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Brandt JM, Charron K, Zhao L, MacDonald SJ, Medley JB. Calf serum constituent fractions influence polyethylene wear and microbial growth in knee simulator testing. Proc Inst Mech Eng H 2012; 226:427-40. [DOI: 10.1177/0954411912444248] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Calf serum lubricants consisting of various polypeptide constituent fractions are routinely used in knee wear simulators as part of the standardized test protocol. Three calf sera (bovine, new-born and alpha) were diluted as per the recommendation of ISO 14243-3 and used in displacement-controlled knee wear simulators to investigate their effects on polyethylene wear. Biochemical analyses included measuring total polypeptide degradation, electrophoretic profiles and low-molecular weight polypeptide concentrations to elucidate their involvement in the wear process. The effects of the various calf sera constituent fractions on microbial growth were also explored. The polyethylene wear rates and the results from the biochemical analyses for the three calf serum lubricants were all found to be statistically significantly different from each other. The lubricant derived from the alpha-calf serum was closest in constituent fractions to human synovial fluid. It also showed the lowest polyethylene wear rate (14.38 ± 0.85 mm3/million cycles) and the lowest amount of polypeptide degradation (7.77 ± 3.87%). Furthermore, the alpha-calf serum lubricant was associated with the least amount of change in the electrophoretic profile, the least change in low-molecular weight polypeptide concentration, and the lowest microbial growth in the presence of sodium azide (a microbial inhibitor conventionally used in implant wear testing). Replacing sodium azide with a broad spectrum antibiotic-antimycotic eradicated the microbial growth. Some speculation was entertained regarding the effect of alpha-calf serum on colloid-mediated boundary lubrication. Based on the results, it was recommended that ISO 14243-3 be modified to include guidelines on calf serum constituent fractions that would favour using alpha-calf serum in order to improve the fidelity of the simulation in knee implant wear testing.
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Affiliation(s)
- Jan-M Brandt
- Concordia Joint Replacement Group, Concordia Hip and Knee Institute, Canada
| | - Kory Charron
- Division of Orthopaedic Surgery, University of Western Ontario, Canada
| | - Lin Zhao
- Department of Biochemistry, University of Western Ontario, Canada
| | | | - John B Medley
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Canada
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12
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Adler HI, Fisher WD, Cohen A, Hardigree AA. MINIATURE escherichia coli CELLS DEFICIENT IN DNA. Proc Natl Acad Sci U S A 2010; 57:321-6. [PMID: 16591472 PMCID: PMC335508 DOI: 10.1073/pnas.57.2.321] [Citation(s) in RCA: 461] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- H I Adler
- BIOLOGY DIVISION, OAK RIDGE NATIONAL LABORATORY
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13
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Abstract
The sensitivity of monolayers of Ilford L-4 nuclear emulsion to beta(-)-particles is approximately 0.20 grain per particle emitted for H(3), and 0.025 grain per particle for p(32). The sensitivity for thick layers is 1.3 grains per tritium beta(-)-particle emitted within the emulsion. In electron microscopic autoradiographs the maximum resolution is approximately 0.1 micron for H(3) and 0.3 micron for p(32).
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14
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Ciznár I, Shands JW. Effect of Alkali on the Immunological Reactivity of Lipopolysaccharide from Salmonella typhimurium. Infect Immun 2010; 2:549-55. [PMID: 16557876 PMCID: PMC416049 DOI: 10.1128/iai.2.5.549-555.1970] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of mild alkaline hydrolysis on the immunological reactivity of Salmonella typhimurium lipopolysaccharide (LPS) was studied. Hydrolysis of LPS at 37 C in 0.01 to 0.25 n NaOH caused a decrease in precipitation of LPS by antiserum. Red cells sensitized with alkali-treated LPS were less responsive to hemagglutination by antiserum than were cells sensitized with heated LPS. Hemagglutination-inhibition studies showed that alkali-treated S. typhimurium LPS was antigenically deficient. Alkaline hydrolysis of S. typhimurium LPS destroys antigen 5 of the Kauffmann-White scheme by cleavage of O-acetyl groups. However, abequose, the immunodominant sugar for antigen 4, is also cleaved from the O side chains by alkali, suggesting the loss of more than one antigenic determinant. It is concluded that alkali treatment of LPS to promote the sensitization of red cells may alter the serological specificity and therefore places limitations on its use in serological studies.
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Affiliation(s)
- I Ciznár
- Department of Microbiology, University of Florida College of Medicine, Gainesville, Florida 32601
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15
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GILLIES NE. The Use of Auxotrophic Mutants to Study Restoration in Escherichia Coli B after Ultra-violet-irradiation. ACTA ACUST UNITED AC 2009; 3:379-87. [PMID: 13705370 DOI: 10.1080/09553006114550441] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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16
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Garber ED, Hackett AJ, Franklin R. The Virulence of Biochemical Mutants of Klebsiella Pneumoniae. Proc Natl Acad Sci U S A 2006; 38:693-7. [PMID: 16589163 PMCID: PMC1063636 DOI: 10.1073/pnas.38.8.693] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- E D Garber
- Naval Biological Laboratory and U. S. Naval Medical Research Unit No. 1, Naval Supply Center, Oakland, California
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17
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Kornberg A, Zimmerman SB, Kornberg SR, Josse J. ENZYMATIC SYNTHESIS OF DEOXYRIBONUCLEIC ACID. INFLUENCE OF BACTERIOPHAGE T2 ON THE SYNTHETIC PATHWAY IN HOST CELLS. Proc Natl Acad Sci U S A 2006; 45:772-85. [PMID: 16590443 PMCID: PMC222636 DOI: 10.1073/pnas.45.6.772] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- A Kornberg
- DEPARTMENT OF MICROBIOLOGY, WASHINGTON UNIVERSITY SCHOOL OF MEDICINE, ST. LOUIS
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18
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Bryson V, Davidson H. Spontaneous and Ultra-Violet-Induced Mutations to Phage Resistance in Escherichia Coli. Proc Natl Acad Sci U S A 2006; 37:784-91. [PMID: 16589028 PMCID: PMC1063471 DOI: 10.1073/pnas.37.12.784] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- V Bryson
- Biological Laboratory, Cold Spring Harbor, New York
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19
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Affiliation(s)
- T F Anderson
- Eldridge Reeves Johnson Research Foundation, University of Pennsylvania, Philadelphia 4, Pennsylvania
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20
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Kelner A. PHOTOREACTIVATION OF ULTRAVIOLET-IRRADIATED ESCHERICHIA COLI, WITH SPECIAL REFERENCE TO THE DOSE-REDUCTION PRINCIPLE AND TO ULTRAVIOLET-INDUCED MUTATION. J Bacteriol 2006; 58:511-22. [PMID: 16561813 PMCID: PMC385659 DOI: 10.1128/jb.58.4.511-522.1949] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- A Kelner
- The Biological Laboratory, Cold Spring Harbor, L. I., New York
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21
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Affiliation(s)
- R B Roberts
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, D. C
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22
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Affiliation(s)
- S S Cohen
- The Children's Hospital of Philadelphia (Department of Pediatrics), Philadelphia
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23
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NEWCOMBE HB, WHITEHEAD HA. Photoreversal of ultraviolet-induced mutagenic and lethal effects in Escherichia coli. J Bacteriol 2004; 61:243-51. [PMID: 14824105 PMCID: PMC385995 DOI: 10.1128/jb.61.3.243-251.1951] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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24
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SANDS MK, ROBERTS RB. The effects of a tryptophan-histidine deficiency in a mutant of Escherichia coli. J Bacteriol 2004; 63:505-11. [PMID: 14938323 PMCID: PMC169301 DOI: 10.1128/jb.63.4.505-511.1952] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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25
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WHITEHEAD HA. A factor released by irradiated cells that induces recovery of viability of ultraviolet irradiated bacteria. Can J Microbiol 2003; 1:266-70. [PMID: 14364350 DOI: 10.1139/m55-034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
From an examination of the dose–survival curve of E. coli B/r, it was evident that the rate of survival increases with the number of cells plated as though the irradiated bacteria themselves contributed some growth restoring activity. Studies on the supernatant fluid from an irradiated suspension indicates the presence of a "restoring factor" which gives up to a fourfold increase in survival of a previously irradiated and washed suspension. The release of the "restoring factor" by irradiated cells is proportional to the rate of killing and not the degree of inactivation. The activity is apparently due to the release of some cellular constituents by living cells as a physiological response to radiation injury and not to cell disintegration products.
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26
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Galhardo RS, Almeida CE, Leitão AC, Cabral-Neto JB. Repair of DNA lesions induced by hydrogen peroxide in the presence of iron chelators in Escherichia coli: participation of endonuclease IV and Fpg. J Bacteriol 2000; 182:1964-8. [PMID: 10715004 PMCID: PMC101895 DOI: 10.1128/jb.182.7.1964-1968.2000] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, the repair of lethal DNA damage induced by H(2)O(2) requires exonuclease III, the xthA gene product. Here, we report that both endonuclease IV (the nfo gene product) and exonuclease III can mediate the repair of lesions induced by H(2)O(2) under low-iron conditions. Neither the xthA nor the nfo mutants was sensitive to H(2)O(2) in the presence of iron chelators, while the xthA nfo double mutant was significantly sensitive to this treatment, suggesting that both exonuclease III and endonuclease IV can mediate the repair of DNA lesions formed under such conditions. Sedimentation studies in alkaline sucrose gradients also demonstrated that both xthA and nfo mutants, but not the xthA nfo double mutant, can carry out complete repair of DNA strand breaks and alkali-labile bonds generated by H(2)O(2) under low-iron conditions. We also found indications that the formation of substrates for exonuclease III and endonuclease IV is mediated by the Fpg DNA glycosylase, as suggested by experiments in which the fpg mutation increased the level of cell survival, as well as repair of DNA strand breaks, in an AP endonuclease-null background.
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Affiliation(s)
- R S Galhardo
- Laboratório de Radiobiologia Molecular, Programa de Biologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Centro de Ciências da Saúde-Bloco G, Universidade Federal do Rio de Janeiro, CEP 21949-900 Rio de Janeiro, RJ, Brazil
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Lage C, Teixeira PC, Leitão AC. Non-coherent visible and infrared radiation increase survival to UV (254 nm) in Escherichia coli K12. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 54:155-61. [PMID: 10836546 DOI: 10.1016/s1011-1344(00)00010-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Interactions between visible or infrared (IR) and ultraviolet (UV, 254 nm) radiation have been studied in E. coli. Pre-illumination with non-coherent monochromatic 446, 466, 570 and 685 nm radiation, as well as with polychromatic red and IR radiation at room temperature, leads to increased cell survival after a subsequent irradiation with UV light. In the thermic range of the spectrum (red and IR), IR but not red light pre-treatment is able to increase cell survival to a subsequent lethal heat (51 degrees C) challenge, suggesting that increased UV survival may be due to IR-induced heat-shock response. On the other hand, visible-light-induced resistance may be due to a different mechanism, possibly involved with unknown bacterial light receptors.
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Affiliation(s)
- C Lage
- Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, UFRJ, Rio de Janeiro, RJ, Brazil.
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Almeida CE, Felício DL, Galhardo RS, Cabral-Neto JB, Leitão AC. Synergistic lethal effect between hydrogen peroxide and neocuproine (2,9-dimethyl 1,10-phenanthroline) in Escherichia coli. Mutat Res 1999; 433:59-66. [PMID: 10047780 DOI: 10.1016/s0921-8777(98)00064-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite 2,9-dimethyl 1,10-phenanthroline (NC) has been extensively used as a potential inhibitor of damage due to oxidative stress in biological systems, the incubation of E. coli cultures with the copper ion chelator NC prior to the challenge with hydrogen peroxide caused a lethal synergistic effect. The SOS response seems to be involved in the repair of the synergistic lesions through the recombination pathway. Furthermore, there is evidence for the UvrABC excinuclease participation in the repair of the synergistic lesions, and the base excision repair may also be required for bacterial survival to the synergistic effect mainly at high concentrations of H2O2, being the action of Fpg protein an important event. Incubation of lexA (Ind-) cultures with iron (II) ion chelator 2,2'-dipyridyl simultaneously with NC prevented the lethal synergistic effect. This result suggests an important role of the Fenton reaction on the phenomenon. NC treatment was able to increase the number of DNA strand breaks (DNAsb) induced by 10 mM of H2O2 in lexA (Ind-) strain and the simultaneous treatment with 2,2'-dipyridyl was able to block this effect.
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Affiliation(s)
- C E Almeida
- Laboratório de Radiobiologia Molecular, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Bloco G, Universidade Federal do Rio de Janeiro, Brazil
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Abstract
Two enzymes, designated, E-2 and E-2', catalyze different oxidation reactions of an aci-reductone intermediate in the methionine salvage pathway. E-2 and E-2', overproduced in Escherichia coli from the same gene, have the same protein component. E-2 and E-2' are separable on an anion exchange column or a hydrophobic column. Their distinct catalytic and chromatographic properties result from binding different metals. The apo-enzyme, obtained after metal is removed from either enzyme, is catalytically inactive. Addition of Ni2+ or Co2+ to the apo-protein yields E-2 activity. E-2' activity is obtained when Fe2+ is added. Production in intact E. coli of E-2 and E-2' depends on the availability of the corresponding metals. These observations suggest that the metal component dictates reaction specificity.
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Affiliation(s)
- Y Dai
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02453-2728, USA
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VAN TUBERGEN RP. The use of radioautography and electron microscopy for the localization of tritium label in bacteria. J Biophys Biochem Cytol 1998; 9:219-22. [PMID: 13780062 PMCID: PMC2224977 DOI: 10.1083/jcb.9.1.219] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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VAN TUBERGEN RP, SETLOW RB. Quantitative radioautographic studies on exponentially growing cultures of Escherichia coli. The distribution of parental DNA, RNA, protein, and cell wall among progeny cells. Biophys J 1998; 1:589-625. [PMID: 13924639 PMCID: PMC1366344 DOI: 10.1016/s0006-3495(61)86911-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Exponentially growing cultures of E. coli were examined by quantitative radioautographic techniques to determine the distribution of labeled DNA, RNA, protein, and cell wall among the progeny cells of successive generations. It was found that DNA is in large structures, non-randomly distributed in the progeny. About one-half of the cells have four such structures and approximately one-half contain these four structures plus four smaller ones. These structures show remarkable stability. Fewer than 3.5 per cent of the large structures break in one division time. Protein, RNA, and cell wall are all distributed randomly among progeny cells. The number of units of each component that show random segregation must be 200 or more.
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Abstract
If thin sections of Escherichia coli, labeled uniformly with tritium, are radioautographed calculations, based on the distribution of section sizes show that the number of H3 decays per section should be very close to a Poisson distribution. We might, therefore, expect that the distribution of radioautographic grain counts among random cross-sections should follow a Poisson distribution. It can then be inferred that a deviation from a Poisson indicates a high concentration of label in a preferred region. This region can then be identified by analysis of serial section and comparison with electron micrographs. Sections of cells labeled with leucine-H3 gave a Poisson distribution of grain counts, and it was concluded that proteins were distributed fairly uniformly throughout the cell. The situation was not changed if labeled cells were placed in chloramphenicol or if very short pulses of label were used. When Escherichia coli is grown in presence of chloramphenicol a major morphological change concerns the nuclear region: it becomes more regular in outline, nearly spherical, and occupies a smaller proportion of the cell length. The previously described association between DNA labeled with thymidine-H3 and the nuclear region was confirmed by showing that the distribution of the label in the cell followed exactly the morphological changes of the nuclear region. It was also shown that the concentration of DNA in the nuclear region was at least 45 times higher than that of the cytoplasm. Several morphological features of cells grown in chloramphenicol and examined in the electron microscope are discussed.
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JARVIS FG, MESENKO MT, TIBBS KE. Production of Vi antigen on a chemically defined medium by a coliform bacterium. J Bacteriol 1998; 80:673-6. [PMID: 13789618 PMCID: PMC278907 DOI: 10.1128/jb.80.5.673-676.1960] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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34
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DENES G. Enzyme repression as the control mechanism in the synthesis of induced beta-galactosidase. Nature 1998; 188:852-3. [PMID: 13721846 DOI: 10.1038/188852a0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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RIBI E, HASKINS WT, LANDY M, MILNER KC. Preparation and host-reactive properties of endotoxin with low content of nitrogen and lipid. ACTA ACUST UNITED AC 1998; 114:647-63. [PMID: 14491836 PMCID: PMC2180377 DOI: 10.1084/jem.114.5.647] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Endotoxins of low lipid content prepared from S. enteritidis by the aqueous ether method have been further treated to remove bound lipid by non-hydrolytic procedures. Such endotoxins, containing as little as 2 per cent lipid A, were as potent in stimulating a variety of physiological responses as those prepared by the well known phenol-water or Boivin procedures which yield products containing as much as 30 per cent lipid A. To verify the difference in lipid content between the aqueous ether preparations and other types of endotoxins, three different methods of lipid analysis were employed: determination of chloroform-soluble material released by hydrolysis with hydrochloric acid (lipid A) or with acetic acid (lipid W), and estimation of total bound fatty acids. These methods were in accord in showing the magnitude of the difference. No more than one-half of the fatty acids present in endotoxin were associated with the fraction designated lipid A. Methods are described for the preparation of potent endotoxins with analytical values for nitrogen, phosphorus, hexosamine, carbohydrate, and fatty acid which do not differ appreciably from those of the classical, non-toxic, haptenic polysaccharides.
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Abstract
Coggin, J. H., Jr. (The University of Chicago, Chicago, Ill.), and W. R. Martin. 6-Diazo-5-oxo-l-norleucine inhibition of Escherichia coli. J. Bacteriol. 89:1348-1353. 1965.-The glutamine analogue 6-diazo-5-oxo-l-norleucine (DON) induced filaments and spheroplasts in Escherichia coli during the transition of sensitive populations to a state of resistance. Resistance developed at a frequency suggesting mutant selection. The morphology of cells resistant to 100 mug of DON per ml was indistinguishable from that of sensitive cells. DON-resistant cells exhibited an extended growth lag when cultured in the absence of the drug. This extended lag could be reduced to the lag time of parent sensitive cells by a combination of d-glucosamine and inosine or by DON. Viable counts during the lag period of resistant cells indicate that this lag results from a decrease in the number of cells during the first 2 hr of incubation. A combination of d-glucosamine and inosine was required for complete prevention of the DON inhibition of sensitive cells. The results indicate that DON not only inhibits de novo purine biosynthesis but that it also prevents hexosamine synthesis and, ultimately, cell-wall synthesis in E. coli.
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ALFOELDI L, STENT GS, HOOGS M, HILL R. PHYSIOLOGICAL EFFECTS OF THE RNA CONTROL (RC) GENE IN E. COLI. Mol Genet Genomics 1996; 94:285-302. [PMID: 14095092 DOI: 10.1007/bf00894773] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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LEBOY PS, COX EC, FLAKS JG. THE CHROMOSOMAL SITE SPECIFYING A RIBOSOMAL PROTEIN IN ESCHERICHIA COLI. Proc Natl Acad Sci U S A 1996; 52:1367-74. [PMID: 14243510 PMCID: PMC300454 DOI: 10.1073/pnas.52.6.1367] [Citation(s) in RCA: 242] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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41
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Jin LZ, Ho YW, Ali MA, Abdullah N, Jalaludin S. Effect of adherent Lactobacillus spp. on in vitro adherence of salmonellae to the intestinal epithelial cells of chicken. THE JOURNAL OF APPLIED BACTERIOLOGY 1996; 81:201-6. [PMID: 8760330 DOI: 10.1111/j.1365-2672.1996.tb04501.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Single strains of Lactobacillus acidophilus and Lact. fermentum, isolated from chicken intestine, were used to study in vitro interactions with Salmonella enteritidis, Salm. pullorum or Salm. typhimurium in an ileal epithelial cell (IEC) radioactive assay. Exclusion, competition and displacement phenomena were investigated by respectively incubating (a) lactobacilli and IEC together, prior to addition of salmonellae, (b) lactobacilli, IEC and salmonellae together, and (c) salmonellae and IEC, followed by the lactobacilli. Lactobacilli were selected for study because of their strong ability to adhere to IEC and poor aggregation with salmonellae. The results demonstrated that Lact. acidophilus significantly reduced (P < 0.05) the attachment of Salm. pullorum to IEC in the tests for exclusion and competition, but not in the displacement tests. Lactobacillus fermentum was found to have some ability to reduce the attachment of Salm. typhimurium to IEC under the conditions of exclusion (P < 0.08), competition (P < 0.09), but not displacement. However, both Lact. acidophilus and Lact. fermentum were unable to reduce the adherence of Salm. enteritidis to IEC under any of the conditions.
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Affiliation(s)
- L Z Jin
- Department of Animal Science, Universiti Pertanian Malaysia, Serdang, Selangor, Malaysia
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42
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Wilson JM, Oliva B, Cassels R, O'Hanlon PJ, Chopra I. SB 205952, a novel semisynthetic monic acid analog with at least two modes of action. Antimicrob Agents Chemother 1995; 39:1925-33. [PMID: 8540693 PMCID: PMC162858 DOI: 10.1128/aac.39.9.1925] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The biological properties of SB 205952, a nitrofuryl oxazole derivative of monic acid, differ from those of the closely related antibacterial agent mupirocin. Compared with mupirocin, SB 205952 has increased antimicrobial potency, an extended spectrum including mupirocin-resistant staphylococci, and rapid bactericidal activity. SB 205952, like mupirocin, is a potent inhibitor of bacterial isoleucyl-tRNA synthetase (IRS) in mupirocin-susceptible organisms but does not inhibit IRS from mupirocin-resistant staphylococci, indicating that SB 205952 has more than one mechanism of action. SB 205952 rapidly inhibits protein, RNA, and DNA syntheses in mupirocin-susceptible and mupirocin-resistant staphylococci. In each case, the effect on RNA synthesis is relaxed by treatment with chloramphenicol, indicating that inhibition of RNA synthesis is probably a secondary consequence of stringent control. It is proposed that SB 205952 possesses one or more mechanisms of action in addition to IRS inhibition, probably mediated by its nitrofuryl component.
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Affiliation(s)
- J M Wilson
- SmithKline Beecham Pharmaceuticals, Brockham Park Research Centre, Betchworth, Surrey, United Kingdom
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43
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Hydrogen peroxide induces the repair of UV-damaged DNA inEscherichia coli: AlexA-independent butuvrA- andrecA-dependent mechanism. Curr Microbiol 1994. [DOI: 10.1007/bf01577443] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Spencer RJ, Chesson A. The effect of Lactobacillus spp. on the attachment of enterotoxigenic Escherichia coli to isolated porcine enterocytes. THE JOURNAL OF APPLIED BACTERIOLOGY 1994; 77:215-20. [PMID: 7961193 DOI: 10.1111/j.1365-2672.1994.tb03066.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A total of 43 strains of lactobacilli were isolated from the gastrointestinal tract of piglets at the time of weaning. Isolates, grown on solid media, were allocated to strongly adherent or non/weakly adherent groups on the basis of numbers attaching to isolated porcine enterocytes. Strains of Lactobacillus fermentum were disproportionally represented amongst the strongly-adherent strains and Lact. acidophilus and Lact. salivarius amongst the non/weakly-adherent group. Lactobacilli showed significantly better attachment ability when grown on agar than when grown in broth culture. Strongly adherent strains were not found to effect the attachment of enterotoxigenic Escherichia coli to porcine enterocytes, tested under the conditions of exclusion (lactobacilli added to the enterocytes before E. coli), competition (lactobacilli and E. coli added simultaneously) and displacement (E. coli added before lactobacilli). Tests were made with [14C]-labelled E. coli. Suspensions of bacteria and enterocytes were passed through a filter selected to retain enterocytes but pass free bacterial cells. Counts (dpm) obtained from filters after solubilization were taken as a measure of E. coli attachment. Some strains of lactobacilli coaggregated with enterotoxigenic E. coli with K88 fimbriae, but not with a K88-negative mutants strain. These were excluded from the competitive exclusion experiments. In the apparent absence of a direct effect on the association of E. coli with host tissue, removal of potential gut pathogens by aggregation could contribute to the probiotic properties ascribed to lactic acid bacteria.
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Affiliation(s)
- R J Spencer
- Rowett Research Institute, Bucksburn, Aberdeen, UK
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45
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Menezes S, Teixeira P. Lethal interaction between heat and methylene blue in Escherichia coli. Int J Hyperthermia 1992; 8:689-99. [PMID: 1402144 DOI: 10.3109/02656739209038004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Hyperthermia treatment is shown to act synergistically with methylene blue (MB), from the end point of lethality in Gram-negative Escherichia coli bacteria. That this lethality is correlated to the damage produced in DNA by the dye is deduced from the fact that bacteria differing in capacity for repair are almost equally sensitive to heat, but differ considerably in sensitivity to concomitant heat and dye treatment. It is demonstrated that the damage is repairable by the excision-repair system. The role of temperature seems to be that of facilitating the incorporation of the dye, which enables the latter to intercalate into the DNA. Ability of the outer membrane of E. coli AB1157 bacteria to act as a barrier to the penetration of MB remains almost intact up to 46 degrees C, but above this temperature it seems to disrupt abruptly (but reversibly), leading to inactivation of the cells by the dye. Since hyperthermia is in current use for the treatment of cancer, it is suggested that if this synergism also exists in mammalian cells, MB could eventually be used independently of its photodynamic action as an adjuvant in cancer therapy.
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Affiliation(s)
- S Menezes
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
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46
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Abstract
Fimbriae (pili) on the surface of bacteria have been suggested to facilitate adherence to mucosal epithelial surfaces. Three Pseudomonas cepacia cystic fibrosis isolates were screened for their ability to agglutinate erythrocytes (HA), a characteristic of some fimbrial types. One strain, designated PC103, was HA+, while another, PC109, was HA-. A fimbriated (f+) HA+ derivative of PC109 (PC2(13)) was selected by repeated erythrocyte adsorption. The two HA+ strains were shown by transmission electron microscopy to possess fimbriae which averaged 4.8 +/- 1.36 nm in width and 200 to greater than 2,100 nm in length (PCE2(13)) and 3.4 to 11.4 nm in diameter and 280 to 720 nm in length (PC103). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins prepared from PC103, PC109, and PCE2(13) indicated that the putative fimbrial subunit had a mass of 16 kDa. Western blot (immunoblot) analysis of sheared cell supernatants indicated that the 16-kDa subunit from PC103 and PCE2(13) reacted with antibody to the P. aeruginosa PAK pilin subunit. Southern blot analysis of a SalI digest of PC103 DNA showed DNA fragments which hybridized to P. aeruginosa PAK probes containing either the pilin structural gene (pilA) or the pilin accessory genes (pilB, -C, and -D) but not the conserved N-terminal region of pilA. A 15-kb band was common to both hybridizations, indicating that this fragment contains the PC103 fimbrial gene cluster. These results indicated the presence of homology between P. aeruginosa PAK and PC103 fimbriae but also suggested that the P. cepacia fimbriae are not type IV-like. The importance of fimbriae in adherence to A549 cells (type II pneumocytes) was assessed with PC109 (f-) and PCE2(13) (f+). PCE2(13) had an approximately 20-fold-higher level of adherence to A549 cells than PC109. This suggested that fimbriation of P. cepacia is associated with increased adherence in vitro.
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Affiliation(s)
- M Kuehn
- Division of Infectious Disease, Children's Hospital, Seattle, Washington
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47
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Bernardo-Filho M, Leitao AC, Alcantara-Gomes R. Neighbour restoration: a possible explanation for some "broken" survival curves of UV-irradiated Escherichia coli K12 cells. J Basic Microbiol 1992; 32:373-80. [PMID: 1487817 DOI: 10.1002/jobm.3620320605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Survival curves for UV irradiation of five non-filamenting strains of E. coli K12 decrease exponentially at moderate levels of radiation but are broken at high levels of radiation. That is, it appears a change in the slope of survival curves, featuring a tail. As this phenomenon was observed with strains bearing uvrA and recA mutations it must be independent of the products of these genes. Experiments with isolated surviving colonies and synchronized cultures eliminated genetic and phenotypic heterogeneity as reasons for the tails in the survival curves. UV survival increased 10- to 15-fold when UV-irradiated cells were plated either with cells unable to grow in the plating medium or with bacterial cell-free extracts. We suggest that factors related to the high cell densities used to obtain survival curves at high radiation levels (neighbour restoration) could be responsible for the survival increases, generating the tailed survival curves.
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Affiliation(s)
- M Bernardo-Filho
- Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Brasil
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48
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Asad NR, Leitão AC. Effects of metal ion chelators on DNA strand breaks and inactivation produced by hydrogen peroxide in Escherichia coli: detection of iron-independent lesions. J Bacteriol 1991; 173:2562-8. [PMID: 2013574 PMCID: PMC207821 DOI: 10.1128/jb.173.8.2562-2568.1991] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In order to study the role of metallic ions in the H2O2 inactivation of Escherichia coli cells, H2O2-sensitive mutants were treated with metal ion chelators and then submitted to H2O2 treatment. o-Phenanthroline, dipyridyl, desferrioxamine, and neocuproine were used as metal chelators. Cell sensitivity to H2O2 treatment was not modified by neocuproine, suggesting that copper has a minor role in OH production in E. coli. On the other hand, prior treatment with iron chelators protected the cells against the H2O2 lethal effect, indicating that iron participates in the production of OH. However, analysis of DNA sedimentation profiles and DNA degradation studies indicated that these chelators did not completely block the formation of DNA single-strand breaks by H2O2 treatment. Thiourea, a scavenger of OH, caused a reduction in both H2O2 sensitivity and DNA single-strand break production. The breaks observed after treatment with metal chelators and H2O2 were repaired 60 min after H2O2 elimination in xthA but not polA mutant cells. Therefore, we propose that there are at least two pathways for H2O2-induced DNA lesions: one produced by H2O2 through iron oxidation and OH production, in which lesions are repaired by the products of the xthA and polA genes, and the other produced by an iron-independent pathway in which DNA repair requires polA gene products but not those of the xthA gene.
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Affiliation(s)
- N R Asad
- Departamento de Radiobiologia, Instituto de Biofísica Carlos, Chagas Filho, Universidade Federal de Rio de Janeiro, Brazil
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49
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Olsen O, Borriss R, Simon O, Thomsen KK. Hybrid Bacillus (1-3,1-4)-beta-glucanases: engineering thermostable enzymes by construction of hybrid genes. MOLECULAR & GENERAL GENETICS : MGG 1991; 225:177-85. [PMID: 2005860 DOI: 10.1007/bf00269845] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hybrid (1-3,1-4)-beta-glucanase genes were constructed by extension of overlapping segments of the (1-3,1-4)-beta-glucanase genes from Bacillus amyloliquefaciens and B. macerans generated by the polymerase chain reaction (PCR). Four hybrid genes were expressed in Escherichia coli cells. The mature hybrid enzymes contain a 16, 36, 78, or 152 amino acid N-terminal sequence derived from B. amyloliquefaciens (1-3,1-4)-beta-glucanase followed by a C-terminal segment derived from B. macerans (1-3,1-4)-beta-glucanase. Biochemical characterization of parental and hybrid enzymes shows a significant increase in thermostability of three of the hybrid enzymes when exposed to an acidic environment thus combining two important enzyme characteristics within the same molecule. At pH 4.1, 85%-95% of the initial activity was retained after 1 h at 65 degrees C in contrast to 5% and 0% for the parental enzymes from B. amyloliquefaciens and B. macerans. After 60 min incubation at 70 degrees C, pH 6.0, the parental enzymes retained 5% or less of the initial activity whilst one of the hybrids still exhibited 90% of the initial activity. Of the parental enzymes B. macerans (1-3,1-4)-beta-glucanase had the lower specific activity while the hybrid enzymes exhibited specific activities that were 1.5- to 3-fold higher. These experimental results demonstrate that exchange of homologous gene segments from different species may be a useful technique for obtaining new and improved versions of biologically active proteins.
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Affiliation(s)
- O Olsen
- Department of Physiology, Carlsberg Laboratory, Copenhagen, Denmark
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50
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Fowler JD, Robertson CR. Metabolic behavior of immobilized aggregates of Escherichia coli under conditions of varying mechanical stress. Appl Environ Microbiol 1991; 57:93-101. [PMID: 2036025 PMCID: PMC182669 DOI: 10.1128/aem.57.1.93-101.1991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Experiments were conducted on immobilized aggregates of Escherichia coli cells. Mechanical stress was applied by forcing a convective stream of nutrient medium through the aggregate. It was shown to be possible to maintain uniform exponential growth with this convective supply of nutrients. Analysis of effluent from the system allowed investigation of metabolic responses unambiguously attributable to mechanical stress. A reversible increase in catabolic activity was observed after an increase in mechanical stress. Changes in the level of catabolism were accompanied by an alteration in the total acid yield on glucose and in the spectrum of organic acids produced during glucose fermentation. The behavior observed here was likely due to an osmoregulatory response induced by the mechanically stressed bacteria to counteract changes in shape.
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Affiliation(s)
- J D Fowler
- Department of Chemical Engineering, Stanford University, California 94305-5025
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