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Correa Deza MA, Salva S, Grillo-Puertas M, Font GM, Gerez CL. Effect of culture parameters on the heat tolerance and inorganic polyphosphate accumulation by Lacticaseibacillus rhamnosus CRL1505, a multifunctional bacterium. World J Microbiol Biotechnol 2023; 39:182. [PMID: 37145244 PMCID: PMC10159826 DOI: 10.1007/s11274-023-03625-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/18/2023] [Indexed: 05/06/2023]
Abstract
Lacticaseibacillus rhamnosus CRL1505 can be used in functional products as a probiotic powder (dried live cells) or as a postbiotic intracellular extract containing inorganic polyphosphate as a functional biopolymer. Thus, the aim of this work was to optimize the production of Lr-CRL1505 depending on the target of the functional product (probiotic or postbiotic). For this purpose, the effect of culture parameters (pH, growth phase) on cell viability, heat tolerance and polyphosphate accumulation by Lacticaseibacillus rhamnosus CRL1505 was evaluated. Fermentations at free pH produced less biomass (0.6 log units) than at controlled pH while the growth phase affected both polyphosphate accumulation and cell heat tolerance. Exponential phase cultures showed 4-15 times greater survival rate against heat shock and 49-62% increased polyphosphate level, compared with the stationary phase. Results obtained allowed setting the appropriate culture conditions for the production of this strain according to its potential application, i.e., as live probiotic cells in powder form or postbiotic. In the first case, running fermentations at pH 5.5 and harvesting the cells at the exponential phase are the best conditions for obtaining a high live biomass yield capable of overcoming heat stress. Whereas the postbiotic formulations production requires fermentations at free pH and harvesting the cells in exponential phase to increase the intracellular polyphosphate level as a first step.
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Affiliation(s)
- M A Correa Deza
- Centro de Referencia para Lactobacilos (CERELA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Tucumán, Argentina
| | - S Salva
- Centro de Referencia para Lactobacilos (CERELA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Tucumán, Argentina
| | - M Grillo-Puertas
- Instituto de Química Biológica, "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT) and Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, San Miguel de Tucumán, Argentina
| | - G M Font
- Centro de Referencia para Lactobacilos (CERELA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Tucumán, Argentina
| | - C L Gerez
- Centro de Referencia para Lactobacilos (CERELA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Tucumán, Argentina.
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Xu J, Guo L, Zhao N, Meng X, Zhang J, Wang T, Wei X, Fan M. Response mechanisms to acid stress of acid-resistant bacteria and biotechnological applications in the food industry. Crit Rev Biotechnol 2023; 43:258-274. [PMID: 35114869 DOI: 10.1080/07388551.2021.2025335] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Acid-resistant bacteria are more and more widely used in industrial production due to their unique acid-resistant properties. In order to survive in various acidic environments, acid-resistant bacteria have developed diverse protective mechanisms such as sensing acid stress and signal transduction, maintaining intracellular pH homeostasis by controlling the flow of H+, protecting and repairing biological macromolecules, metabolic modification, and cross-protection. Acid-resistant bacteria have broad biotechnological application prospects in the food field. The production of fermented foods with high acidity and acidophilic enzymes are the main applications of this kind of bacteria in the food industry. Their acid resistance modules can also be used to construct acid-resistant recombinant engineering strains for special purposes. However, they can also cause negative effects on foods, such as spoilage and toxicity. Herein, the aim of this paper is to summarize the research progress of molecular mechanisms against acid stress of acid-resistant bacteria. Moreover, their effects on the food industry were also discussed. It is useful to lay a foundation for broadening our understanding of the physiological metabolism of acid-resistant bacteria and better serving the food industry.
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Affiliation(s)
- Junnan Xu
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Li Guo
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Ning Zhao
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Xuemei Meng
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Jie Zhang
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Tieru Wang
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Xinyuan Wei
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Mingtao Fan
- College of Food Science and Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
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Xue J, Lei D, Zhao X, Hu Y, Yao S, Lin K, Wang Z, Cui C. Antibiotic residue and toxicity assessment of wastewater during the pharmaceutical production processes. CHEMOSPHERE 2022; 291:132837. [PMID: 34762889 DOI: 10.1016/j.chemosphere.2021.132837] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 09/25/2021] [Accepted: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Various pollutants are released during pharmaceutical production processes, which is of great concern. Most studies have focused on the terminal treatment results of mixed pharmaceutical wastewater, and further research on wastewater from the production processes is required. This study investigated the wastewater quality indicators, residual antibiotics, and biological toxicity of the wastewater during the production process in a large pharmaceutical producing factory in Northern China. The wastewater contained numerous organic pollutants, with the chemical oxygen demand (COD) values ranging from 2.0 × 103 to 2.6 × 105 mg L-1 and the total nitrogen (TN) values ranging from 1.3 × 103 to 2.0 × 104 mg L-1. High concentrations of cephalexin and cefradine remained in the wastewater of the production workshop, with the highest concentration of cefradine reaching 1328 mg L-1. The wastewater from the oxidation and solvent recovery workshops was more toxic to Vibrio fischeri and Daphnia magna than that of other workshops. Moreover, the biological acute toxicity of wastewater was significantly correlated with the concentration of COD and TN (p < 0.01). This study provides new insights into the treatment of antibiotic production wastewater, illuminating the incomplete extraction of products and the significant risk posed by pharmaceutical wastewater to the environment.
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Affiliation(s)
- JiaJia Xue
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Environmental Protection Key Laboratory on Environmental Standard and Risk Management of Chemical Pollutants, East China University of Science & Technology, Shanghai, 200237, China
| | - Dandan Lei
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Xiumei Zhao
- Environmental Protection Department of North China Pharmaceutical Company Limited, Shijiazhuang, 050015, China
| | - Yaru Hu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Shijie Yao
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Kuangfei Lin
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Zejian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Changzheng Cui
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Environmental Protection Key Laboratory on Environmental Standard and Risk Management of Chemical Pollutants, East China University of Science & Technology, Shanghai, 200237, China.
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4
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Distinct metabolic flow in response to temperature in thermotolerant Kluyveromyces marxianus. Appl Environ Microbiol 2022; 88:e0200621. [PMID: 35080905 DOI: 10.1128/aem.02006-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intrinsic mechanism of the thermotolerance of Kluyveromyces marxianus was investigated by comparison of its physiological and metabolic properties at high and low temperatures. After glucose consumption, the conversion of ethanol to acetic acid became gradually prominent only at high temperature (45°C) and eventually caused a decline in viability, which was prevented by exogenous glutathione. Distinct levels of reactive oxygen species (ROS), glutathione, and NADPH suggest greater accumulation of ROS and enhanced ROS-scavenging activity at a high temperature. Fusion and fission forms of mitochondria were dominantly observed at 30°C and 45°C, respectively. Consistent results were obtained by temperature up-shift experiments including transcriptomic and enzymatic analyses, suggesting a change of metabolic flow from glycolysis to the pentose phosphate pathway. Results of this study suggest that K. marxianus survives at a high temperature by scavenging ROS via metabolic change for a period until a critical concentration of acetate is reached. IMPORTANCE Kluyveromyces marxianus, a thermotolerant yeast, can grow well at temperatures over 45°C, unlike Kluyveromyces lactis, which belongs to the same genus, or Saccharomyces cerevisiae, which is a closely related yeast. K. marxianus may thus bear an intrinsic mechanism to survive at high temperatures. This study revealed the thermotolerant mechanism of the yeast, including ROS scavenging with NADPH, which is generated by changes in metabolic flow.
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Liu Y, Zhu L, Dong P, Liang R, Mao Y, Yang X, Zhang Y, Luo X. Acid Tolerance Response of Listeria monocytogenes in Various External pHs with Different Concentrations of Lactic Acid. Foodborne Pathog Dis 2020; 17:253-261. [PMID: 31738578 DOI: 10.1089/fpd.2019.2730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study evaluated the acid tolerance response (ATR) of two strains of Listeria monocytogenes (serotype 1/2a and 4b) and one strain of Listeria innocua under different mildly acid conditions. Cells were incubated in combinations of three concentrations of lactic acid medium (3, 4.75, and 15 mM) and three external pH's (pHex 5.0, 6.0, and 6.5), plus, a HCl control, and a blank control (pH 7.4). Results showed that lactic acid induced lower log reduction of all three strains when challenged in severe acid conditions (pH 3.0) after being habituated at a pHex of 5.5 or 6.0 until the log phase, compared with a pHex of 6.5 or the two controls. This indicates that when the pHex was either 5.5 or 6.0 this induced a higher ATR of the strains, which may be caused by the ability of the strains to retain intracellular pH (pHi) homeostasis with pHi maintained in the range of 7.4-7.9. It was also found that a pHex of 5.5 resulted in the highest pHi of the strains across all incubated conditions, which indicates that the pHi may play an important role in the induction of ATR when Listeria cells are habituated in lactic acid, and if the higher pHi can be maintained, the ATR would be stronger. The concentration of lactic acid per se has no significant effect on ATR, which it is proposed was due to the pHi homeostasis maintained within the cells. However, the difference in ATR among three strains was also significant, which cannot be explained by the stable pHi of all tested strains. Therefore, other underlying mechanisms to mediate ATR under different conditions need to be explored in further studies.
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Affiliation(s)
- Yunge Liu
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Lixian Zhu
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Pengcheng Dong
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Rongrong Liang
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Yanwei Mao
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Xiaoyin Yang
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Yimin Zhang
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
| | - Xin Luo
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, People's Republic of China
- National R&D Center for Beef Processing Technology, Tai'an, People's Republic of China
- Jiangsu Synergetic Innovation Center of Meat Production and Processing Quality and Safety Control, Nanjing, People's Republic of China
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Augagneur Y, King AN, Germain-Amiot N, Sassi M, Fitzgerald JW, Sahukhal GS, Elasri MO, Felden B, Brinsmade SR. Analysis of the CodY RNome reveals RsaD as a stress-responsive riboregulator of overflow metabolism in Staphylococcus aureus. Mol Microbiol 2019; 113:309-325. [PMID: 31696578 DOI: 10.1111/mmi.14418] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2019] [Indexed: 11/28/2022]
Abstract
In Staphylococcus aureus, the transcription factor CodY modulates the expression of hundreds of genes, including most virulence factors, in response to the availability of key nutrients like GTP and branched-chain amino acids. Despite numerous studies examining how CodY controls gene expression directly or indirectly, virtually nothing is known about the extent to which CodY exerts its effect through small regulatory RNAs (sRNAs). Herein, we report the first set of sRNAs under the control of CodY. We reveal that staphylococcal sRNA RsaD is overexpressed >20-fold in a CodY-deficient strain in three S. aureus clinical isolates and in S. epidermidis. We validated the CodY-dependent regulation of rsaD and demonstrated that CodY directly represses rsaD expression by binding the promoter. Using a combination of molecular techniques, we show that RsaD posttranscriptionally regulates alsS (acetolactate synthase) mRNA and enzyme levels. We further show that RsaD redirects carbon overflow metabolism, contributing to stationary phase cell death during exposure to weak acid stress. Taken together, our data delineate a role for CodY in controlling sRNA expression in a major human pathogen and indicate that RsaD may integrate nutrient depletion and other signals to mount a response to physiological stress experienced by S. aureus in diverse environments.
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Affiliation(s)
- Yoann Augagneur
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
| | - Alyssa N King
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Mohamed Sassi
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
| | | | - Gyan S Sahukhal
- Center of Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Mohamed O Elasri
- Center of Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Brice Felden
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
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Kudo H, Sasaki Y. Intracellular pH Determination for the Study of Acid Tolerance of Lactic Acid Bacteria. Methods Mol Biol 2019; 1887:33-41. [PMID: 30506247 DOI: 10.1007/978-1-4939-8907-2_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
It is important to assess acid tolerance in lactic acid bacteria, particularly for probiotics, although it involves multiple mechanisms. Measuring the difference between intracellular and extracellular pH (ΔpH) using the fluorescent probe CFDA-SE is particularly effective for such assessments because it gives direct information on the level of tolerance in the extracellular acidic pH range from 7 to 2.5. It also enables acid adaptation to be induced and observed by slowly introducing HCl into the medium and decreasing the extracellular pH. The difference of acid tolerance between anaerobic and aerobic conditions in lactic acid bacteria can also be evaluated by measuring ΔpH.
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8
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Selection of oleaginous yeasts capable of high lipid accumulation during challenges from inhibitory chemical compounds. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.05.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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9
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Two-step production of anti-inflammatory soluble factor by Lactobacillus reuteri CRL 1098. PLoS One 2018; 13:e0200426. [PMID: 29979794 PMCID: PMC6034873 DOI: 10.1371/journal.pone.0200426] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/26/2018] [Indexed: 01/28/2023] Open
Abstract
We have demonstrated previously that a soluble factor (LrS) produced by Lactobacillus (L.) reuteri CRL 1098 modulates the inflammatory response triggered by lipopolysaccharide. In this study, the production of LrS by L. reuteri CRL 1098 was realized through two steps: i) bacterial biomass production, ii) LrS production, where the bacterial biomass was able to live but did not proliferate. Therefore, the simultaneous evaluation of the effect of different factors on the growth and LrS production was performed. Biomass production was found to be dependent mainly on culture medium, while LrS production with anti-inflammatory activity depended on culture conditions of the biomass such as pH, agitation and growth phase. The L. reuteri CRL 1098 biomass and LrS production in the optimized culture media designed for this work reduced the complete process cost by approximately 95%, respectively to laboratory scale cost.
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10
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Sannasiddappa TH, Lund PA, Clarke SR. In Vitro Antibacterial Activity of Unconjugated and Conjugated Bile Salts on Staphylococcus aureus. Front Microbiol 2017; 8:1581. [PMID: 28878747 PMCID: PMC5572772 DOI: 10.3389/fmicb.2017.01581] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/03/2017] [Indexed: 12/12/2022] Open
Abstract
Bile salts are potent antimicrobial agents and are an important component of innate defenses in the intestine, giving protection against invasive organisms. They play an important role in determining microbial ecology of the intestine and alterations in their levels can lead to increased colonization by pathogens. We have previously demonstrated survival of the opportunistic pathogen Staphylococcus aureus in the human colonic model. Thus investigating the interaction between S. aureus and bile salts is an important factor in understanding its ability to colonize in the host intestine. Harnessing bile salts may also give a new avenue to explore in the development of therapeutic strategies to control drug resistant bacteria. Despite this importance, the antibacterial activity of bile salts on S. aureus is poorly understood. In this study, we investigated the antibacterial effects of the major unconjugated and conjugated bile salts on S. aureus. Several concentration-dependent antibacterial mechanisms were found. Unconjugated bile salts at their minimum inhibitory concentration (cholic and deoxycholic acid at 20 and 1 mM, respectively) killed S. aureus, and this was associated with increased membrane disruption and leakage of cellular contents. Unconjugated bile salts (cholic and deoxycholic acid at 8 and 0.4 mM, respectively) and conjugated bile salts (glycocholic and taurocholic acid at 20 mM) at their sub inhibitory concentrations were still able to inhibit growth through disruption of the proton motive force and increased membrane permeability. We also demonstrated that unconjugated bile salts possess more potent antibacterial action on S. aureus than conjugated bile salts.
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Affiliation(s)
| | - Peter A Lund
- Institute of Microbiology and Infection, School of Biosciences, University of BirminghamBirmingham, United Kingdom
| | - Simon R Clarke
- School of Biological Sciences, University of ReadingReading, United Kingdom
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11
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Salim APAA, Canto ACVCS, Costa-Lima BRC, Simoes JS, Panzenhagen PHN, Costa MP, Franco RM, Silva TJP, Conte-Junior CA. Inhibitory effect of acid concentration, aging, and different packaging onEscherichia coliO157:H7 and on color stability of beef. J FOOD PROCESS PRES 2017. [DOI: 10.1111/jfpp.13402] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ana Paula A. A. Salim
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
- Programa de Pós Graduação em Ciência de Alimentos; Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ); Rio de Janeiro, 21949-900, Rio de Janeiro Brazil
| | - Anna C. V. C. S. Canto
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Bruno R. C. Costa-Lima
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Julia S. Simoes
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Pedro H. N. Panzenhagen
- Programa de Pós Graduação em Ciência de Alimentos; Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ); Rio de Janeiro, 21949-900, Rio de Janeiro Brazil
| | - Marion P. Costa
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Robson M. Franco
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Teófilo J. P. Silva
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
| | - Carlos A. Conte-Junior
- Departamento de Tecnologia de Alimentos, Faculdade de Veterinaria; Universidade Federal Fluminense (UFF); Niteroi, 24230-340 Rio de Janeiro Brazil
- Programa de Pós Graduação em Ciência de Alimentos; Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ); Rio de Janeiro, 21949-900, Rio de Janeiro Brazil
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12
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Duport C, Jobin M, Schmitt P. Adaptation in Bacillus cereus: From Stress to Disease. Front Microbiol 2016; 7:1550. [PMID: 27757102 PMCID: PMC5047918 DOI: 10.3389/fmicb.2016.01550] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/15/2016] [Indexed: 12/23/2022] Open
Abstract
Bacillus cereus is a food-borne pathogen that causes diarrheal disease in humans. After ingestion, B. cereus experiences in the human gastro-intestinal tract abiotic physical variables encountered in food, such as acidic pH in the stomach and changing oxygen conditions in the human intestine. B. cereus responds to environmental changing conditions (stress) by reversibly adjusting its physiology to maximize resource utilization while maintaining structural and genetic integrity by repairing and minimizing damage to cellular infrastructure. As reviewed in this article, B. cereus adapts to acidic pH and changing oxygen conditions through diverse regulatory mechanisms and then exploits its metabolic flexibility to grow and produce enterotoxins. We then focus on the intricate link between metabolism, redox homeostasis, and enterotoxins, which are recognized as important contributors of food-borne disease.
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Affiliation(s)
- Catherine Duport
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
| | - Michel Jobin
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
| | - Philippe Schmitt
- Sécurité et Qualité des Produits d'Origine Végétale, UMR0408, Avignon Université, Institut National de la Recherche Agronomique Avignon, France
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13
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Peterson ND, Rosen BC, Dillon NA, Baughn AD. Uncoupling Environmental pH and Intrabacterial Acidification from Pyrazinamide Susceptibility in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2015; 59:7320-6. [PMID: 26369957 PMCID: PMC4649215 DOI: 10.1128/aac.00967-15] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 09/07/2015] [Indexed: 01/17/2023] Open
Abstract
Pyrazinamide (PZA) is a first-line antitubercular drug for which the mode of action remains unresolved. Mycobacterium tuberculosis lacks measurable susceptibility to PZA under standard laboratory growth conditions. However, susceptibility to this drug can be induced by cultivation of the bacilli in an acidified growth medium. Previous reports suggested that the active form of PZA, pyrazinoic acid (POA), operates as a proton ionophore that confers cytoplasmic acidification when M. tuberculosis is exposed to an acidic environment. In this study, we demonstrate that overexpression of the PZA-activating enzyme PncA can confer PZA susceptibility to M. tuberculosis under neutral and even alkaline growth conditions. Furthermore, we find that wild-type M. tuberculosis displays increased susceptibility to POA relative to PZA in neutral and alkaline media. Utilizing a strain of M. tuberculosis that expresses a pH-sensitive green fluorescent protein (GFP), we find that unlike the bona fide ionophores monensin and carbonyl cyanide 3-chlorophenylhydrazone, PZA and POA do not induce rapid uncoupling or cytoplasmic acidification under conditions that promote susceptibility. Thus, based on these observations, we conclude that the antitubercular action of POA is independent of environmental pH and intrabacterial acidification.
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Affiliation(s)
- Nicholas D Peterson
- Department of Microbiology and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Brandon C Rosen
- Department of Microbiology and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Nicholas A Dillon
- Department of Microbiology and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Anthony D Baughn
- Department of Microbiology and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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14
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Adaptation and tolerance of bacteria against acetic acid. Appl Microbiol Biotechnol 2015; 99:6215-29. [DOI: 10.1007/s00253-015-6762-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/05/2015] [Accepted: 06/15/2015] [Indexed: 10/23/2022]
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Ortiz ME, Raya RR, Mozzi F. Efficient mannitol production by wild-type Lactobacillus reuteri CRL 1101 is attained at constant pH using a simplified culture medium. Appl Microbiol Biotechnol 2015; 99:8717-29. [PMID: 26084891 DOI: 10.1007/s00253-015-6730-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/21/2015] [Accepted: 05/26/2015] [Indexed: 11/29/2022]
Abstract
Mannitol is a natural polyol with multiple industrial applications. In this work, mannitol production by Lactobacillus reuteri CRL 1101 was studied at free- and controlled-pH (6.0-4.8) fermentations using a simplified culture medium containing yeast and beef extracts and sugarcane molasses. The activity of mannitol 2-dehydrogenase (MDH), the enzyme responsible for mannitol synthesis, was determined. The effect of the initial biomass concentration was further studied. Mannitol production (41.5 ± 1.1 g/l), volumetric productivity (Q Mtl 1.73 ± 0.05 g/l h), and yield (Y Mtl 105 ± 11 %) were maximum at pH 5.0 after 24 h while the highest MDH activity (1.66 ± 0.09 U/mg protein) was obtained at pH 6.0. No correlation between mannitol production and MDH activity was observed when varying the culture pH. The increase (up to 2000-fold) in the initial biomass concentration did not improve mannitol formation after 24 h although a 2-fold higher amount was produced at 8 h using 1 or 2 g cell dry weight/l comparing to the control (0.001 g cell dry weight/l). Finally, mannitol isolation under optimum fermentation conditions was achieved. The mannitol production obtained in this study is the highest reported so far by a wild-type L. reuteri strain and, more interestingly, using a simplified culture medium.
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Affiliation(s)
- Maria Eugenia Ortiz
- Departamento de Tecnología y Desarrollo, Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, 4000, San Miguel de Tucumán, Argentina
| | - Raúl R Raya
- Departamento de Tecnología y Desarrollo, Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, 4000, San Miguel de Tucumán, Argentina
| | - Fernanda Mozzi
- Departamento de Tecnología y Desarrollo, Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, 4000, San Miguel de Tucumán, Argentina.
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16
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Wang H, Wang F, Wang W, Yao X, Wei D, Cheng H, Deng Z. Improving the expression of recombinant proteins in E. coli BL21 (DE3) under acetate stress: an alkaline pH shift approach. PLoS One 2014; 9:e112777. [PMID: 25402470 PMCID: PMC4234529 DOI: 10.1371/journal.pone.0112777] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 10/20/2014] [Indexed: 11/23/2022] Open
Abstract
Excess acetate has long been an issue for the production of recombinant proteins in E. coli cells. Recently, improvements in acetate tolerance have been achieved through the use of genetic strategies and medium supplementation with certain amino acids and pyrimidines. The aim of our study was to evaluate an alternative to improve the acetate tolerance of E. coli BL21 (DE3), a popular strain used to express recombinant proteins. In this work we reported the cultivation of BL21 (DE3) in complex media containing acetate at high concentrations. In the presence of 300 mM acetate, compared with pH 6.5, pH 7.5 improved cell growth by approximately 71%, reduced intracellular acetate by approximately 50%, and restored the expression of glutathione S-transferase (GST), green fluorescent protein (GFP) and cytochrome P450 monooxygenase (CYP). Further experiments showed that alkaline pHs up to 8.5 had little inhibition in the expression of GST, GFP and CYP. In addition, the detrimental effect of acetate on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) by the cell membrane, an index of cellular metabolic capacity, was substantially alleviated by a shift to alkaline pH values of 7.5–8.0. Thus, we suggest an approach of cultivating E. coli BL21 (DE3) at pH 8.0±0.5 to minimize the effects caused by acetate stress. The proposed strategy of an alkaline pH shift is a simple approach to solving similar bioprocessing problems in the production of biofuels and biochemicals from sugars.
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Affiliation(s)
- Hengwei Wang
- Innovation & Application Institute (IAI), Zhejiang Ocean University, Zhoushan, China
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Fengqing Wang
- New World Institute of Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Wei Wang
- New World Institute of Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Xueling Yao
- New World Institute of Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Dongzhi Wei
- New World Institute of Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Hairong Cheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail:
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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17
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Broadbent JR, Oberg TS, Hughes JE, Ward RE, Brighton C, Welker DL, Steele JL. Influence of polysorbate 80 and cyclopropane fatty acid synthase activity on lactic acid production by Lactobacillus casei ATCC 334 at low pH. ACTA ACUST UNITED AC 2014; 41:545-53. [DOI: 10.1007/s10295-013-1391-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 12/04/2013] [Indexed: 11/30/2022]
Abstract
Abstract
Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid’s pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH4OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8.
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Affiliation(s)
- J R Broadbent
- grid.53857.3c 0000000121858768 Department of Nutrition, Dietetics, and Food Science Utah State University 8700 Old Main Hill 84322-8700 Logan UT USA
| | - T S Oberg
- grid.53857.3c 0000000121858768 Department of Nutrition, Dietetics, and Food Science Utah State University 8700 Old Main Hill 84322-8700 Logan UT USA
| | - J E Hughes
- grid.53857.3c 0000000121858768 Department of Biology Utah State University Logan UT USA
| | - R E Ward
- grid.53857.3c 0000000121858768 Department of Nutrition, Dietetics, and Food Science Utah State University 8700 Old Main Hill 84322-8700 Logan UT USA
| | - C Brighton
- grid.53857.3c 0000000121858768 Department of Nutrition, Dietetics, and Food Science Utah State University 8700 Old Main Hill 84322-8700 Logan UT USA
| | - D L Welker
- grid.53857.3c 0000000121858768 Department of Biology Utah State University Logan UT USA
| | - J L Steele
- grid.14003.36 0000000099041312 Department of Food Science University of Wisconsin Madison USA
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Zhai Z, Douillard FP, An H, Wang G, Guo X, Luo Y, Hao Y. Proteomic characterization of the acid tolerance response inLactobacillus delbrueckiisubsp.bulgaricus CAUH1 and functional identification of a novel acid stress-related transcriptional regulator Ldb0677. Environ Microbiol 2013; 16:1524-37. [DOI: 10.1111/1462-2920.12280] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 09/06/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Zhengyuan Zhai
- Key Laboratory of Functional Dairy; Co-constructed by Ministry of Education and Beijing Municipality; College of Food Science and Nutritional Engineering; China Agricultural University; Beijing 100083 China
| | | | - Haoran An
- Key Laboratory of Functional Dairy; Co-constructed by Ministry of Education and Beijing Municipality; College of Food Science and Nutritional Engineering; China Agricultural University; Beijing 100083 China
| | - Guohong Wang
- Key Laboratory of Functional Dairy; Co-constructed by Ministry of Education and Beijing Municipality; College of Food Science and Nutritional Engineering; China Agricultural University; Beijing 100083 China
| | - Xinghua Guo
- Institute of Microbiology; Chinese Academy of Sciences; Beijing 100101 China
| | - Yunbo Luo
- Key Laboratory of Functional Dairy; Co-constructed by Ministry of Education and Beijing Municipality; College of Food Science and Nutritional Engineering; China Agricultural University; Beijing 100083 China
| | - Yanling Hao
- Key Laboratory of Functional Dairy; Co-constructed by Ministry of Education and Beijing Municipality; College of Food Science and Nutritional Engineering; China Agricultural University; Beijing 100083 China
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Ji JY, Xing YJ, Ma ZT, Cai J, Zheng P, Lu HF. Toxicity assessment of anaerobic digestion intermediates and antibiotics in pharmaceutical wastewater by luminescent bacterium. JOURNAL OF HAZARDOUS MATERIALS 2013; 246-247:319-323. [PMID: 23334482 DOI: 10.1016/j.jhazmat.2012.12.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 10/30/2012] [Accepted: 12/12/2012] [Indexed: 06/01/2023]
Abstract
In order to evaluate the effect of anaerobic digestion intermediates and antibiotics in pharmaceutical wastewaters on anaerobic digestion process, their acute toxicities were tested using the 15 min median inhibitory concentration (IC(50)) at pH 7.00 ± 0.05. The results showed that the IC(50) of ethanol, acetate, propionate and butyrate were 19.40, 20.71, 10.47 and 12.17 g L(-1) respectively, which suggested the toxicity descended in the order of propionate, butyrate, ethanol and acetate. The IC(50) of aureomycin, polymyxin and chloromycetin were 12.06, 6.24 and 429.90 mg L(-1) respectively, which indicated the toxicity descended in the order of polymyxin, aureomycin and chloromycetin. Using equitoxic ratio mixing method, the joint toxicities of five groups referred by A (four anaerobic digestion intermediates), B (four anaerobic digestion intermediates and aureomycin), C (four anaerobic digestion intermediates and polymyxin), D (four anaerobic digestion intermediates and chloromycetin) and E (four anaerobic digestion intermediates, aureomycin, polymyxin and chloromycetin) were investigated respectively. Their interactions were additive (A), synergistic (B), additive (C), synergistic (D) and synergistic (E). The investigation would lay a basis for the optimization of anaerobic biotechnology for pharmaceutical wastewater treatment.
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Affiliation(s)
- Jun-Yuan Ji
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
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20
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Rasolofo EA, LaPointe G, Roy D. Assessment of the bacterial diversity of treated and untreated milk during cold storage by T-RFLP and PCR-DGGE methods. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s13594-011-0027-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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21
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Physiological and transcriptional response of Lactobacillus casei ATCC 334 to acid stress. J Bacteriol 2010; 192:2445-58. [PMID: 20207759 DOI: 10.1128/jb.01618-09] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
This study investigated features of the acid tolerance response (ATR) in Lactobacillus casei ATCC 334. To optimize ATR induction, cells were acid adapted for 10 or 20 min at different pH values (range, 3.0 to 5.0) and then acid challenged at pH 2.0. Adaptation over a broad range of pHs improved acid tolerance, but the highest survival was noted in cells acid adapted for 10 or 20 min at pH 4.5. Analysis of cytoplasmic membrane fatty acids (CMFAs) in acid-adapted cells showed that they had significantly (P < 0.05) higher total percentages of saturated and cyclopropane fatty acids than did control cells. Specifically, large increases in the percentages of C(14:0), C(16:1n(9)), C(16:0), and C(19:0(11c)) were noted in the CMFAs of acid-adapted and acid-adapted, acid-challenged cells, while C(18:1n(9)) and C(18:1n(11)) showed the greatest decrease. Comparison of the transcriptome from control cells (grown at pH 6.0) against that from cells acid adapted for 20 min at pH 4.5 indicated that acid adaption invoked a stringent-type response that was accompanied by other functions which likely helped these cells resist acid damage, including malolactic fermentation and intracellular accumulation of His. Validation of microarray data was provided by experiments that showed that L. casei survival at pH 2.5 was improved at least 100-fold by chemical induction of the stringent response or by the addition of 30 mM malate or 30 mM histidine to the acid challenge medium. To our knowledge, this is the first report that intracellular histidine accumulation may be involved in bacterial acid resistance.
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22
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Raftari M, Jalilian FA, Abdulamir A, Son R, Sekawi Z, Fatimah A. Effect of organic acids on Escherichia coli O157:H7 and Staphylococcus aureus contaminated meat. Open Microbiol J 2009; 3:121-7. [PMID: 19696918 PMCID: PMC2729390 DOI: 10.2174/1874285800903010121] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 06/24/2009] [Accepted: 06/25/2009] [Indexed: 11/22/2022] Open
Abstract
Appropriate and safe antibacterial agents able to decontaminate meat surfaces have long been big concern of meat industry. In an attempt to manage beef carcass contamination, spray wash treatments utilizing three concentrations (1, 1.5 and 2%) of acetic, lactic, propionic and formic acids were performed to evaluate their efficacy in reducing numbers of Escherichia coli O157:H7 and Staphylococcus aureus on meat tissues. The procured beef pieces of freshly slaughtered animals were decontaminated with hot water and then inoculated with E. coli O157:H7 and S. aureus individually which then were spray washed with organic acids separately. The total plate count of the treated samples showed that the populations of bacteria decreased after being exposed to organic acids. Spray wash of formic acid resulted in the highest reduction of both bacterial species on meat surface. Significantly, higher log reductions were obtained for S. aureus than E. coli O157:H7. It was concluded that organic acids are highly effective in decontaminating meat surfaces and organic acids are shown to be safe, simple, efficient, and cheap modality of meat decontamination which can be highly recommended for industrial scales.
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Affiliation(s)
- M Raftari
- Faculty of Food Science and Technology, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
| | - F. Azizi Jalilian
- Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
| | - A.S Abdulamir
- Microbiology research department, Institute of Bioscience, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
| | - R Son
- Faculty of Food Science and Technology, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
| | - Z Sekawi
- Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
| | - A.B Fatimah
- Faculty of Food Science and Technology, Universiti Putra Malaysia, 43300, Serdang, Selangor, Malaysia
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Alexander TW, Wang Y, Reuter T, Okine EK, Dixon WT, McAllister TA. Use of real-time PCR to predict dry matter disappearance of individual feeds in a total mixed ration. Anim Feed Sci Technol 2009. [DOI: 10.1016/j.anifeedsci.2008.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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24
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25
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Russell J. Another explanation for the toxicity of fermentation acids at low pH: anion accumulation versus uncoupling. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1992.tb04990.x] [Citation(s) in RCA: 322] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Russell JB. The energy spilling reactions of bacteria and other organisms. J Mol Microbiol Biotechnol 2007; 13:1-11. [PMID: 17693707 DOI: 10.1159/000103591] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
For many years it was assumed that living organisms always utilized ATP in a highly efficient manner, but simple growth studies with bacteria indicated that the efficiency of biomass production was often at least 3-fold lower than the amount that would be predicted from standard biosynthetic pathways. The utilization of energy for maintenance could only explain a small portion of this discrepancy particularly when the growth rate was high. These ideas and thermodynamic arguments indicated that cells might have another avenue of energy utilization. This phenomenon has also been called 'uncoupling', 'spillage' and 'overflow metabolism', but 'energy spilling' is probably the most descriptive term. It appears that many bacteria spill energy, and the few that do not can be killed (large and often rapid decrease in viability), if the growth medium is nitrogen-limited and the energy source is in 'excess'. The lactic acid bacterium, Streptococcus bovis, is an ideal bacterium for the study of energy spilling. Because it only uses substrate level phosphorylation to generate ATP, ATP generation can be calculated with a high degree of certainty. It does not store glucose as glycogen, and its cell membrane can be easily accessed. Comparative analysis of heat production, membrane voltage, ATP production and Ohm's law indicated that the energy spilling reaction of S. bovis is mediated by a futile cycle of protons through the cell membrane. Less is known about Escherichia coli, but in this bacterium energy spilling could be mediated by a futile cycle of potassium or ammonium ions. Energy spilling is not restricted to prokaryotes and appears to occur in yeasts and in higher organisms. In man, energy spilling may be related to cancer, ageing, ischemia and cardiac failure.
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Affiliation(s)
- James B Russell
- US Plant, Soil and Nutrition Laboratory, Agricultural Research Service, USDA, Ithaca, NY 14853, USA.
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27
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Huang HY, Huang SY, Chen PY, King VAE, Lin YP, Tsen JH. Basic Characteristics of Sporolactobacillus inulinus BCRC 14647 for Potential Probiotic Properties. Curr Microbiol 2007; 54:396-404. [PMID: 17387552 DOI: 10.1007/s00284-006-0496-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Accepted: 11/08/2006] [Indexed: 10/23/2022]
Abstract
The basic characteristics of the spore-forming lactic acid bacterium, Sporolactobacillus inulinus BCRC 14647, was evaluated in vitro for its potential probiotic properties. Assessments including acid and bile salt tolerance, adhesiveness, and antagonistic effects on pathogenic Salmonella enteritidis BCRC 10744, as well as inhibition factors of spent culture supernatant (SCS) and an invasion assay, were conducted using Lactobacillus acidophilus BCRC 10695 and two bifidobacteria (Bifidobacterium bifidum BCRC 14615 and B. longum BCRC 11847) as a reference. In the results, S. inulinus spores presented significantly higher survival rates than the vegetative cell form in acidic conditions as well as the reference bifidobacteria. However, L. acidophilus showed the highest viability among all tested strains. Similar results were found in the bile tolerance test. Compared with the reference strains, the vegetative cell form of S. inulinus possessed a proper adhesive characteristic (71.7 bacteria/field for S. inulinus and 91.3 and 45.7 bacteria/field for B. bifidum and B. longum, respectively). In the adhesion assay, both the spore form of S. inulinus (17.1 bacteria/field) and the negative control, L. bulgaricus BCRC 14009 (5.9 bacteria/field), displayed nonadhesive traits. The vegetative cells of S. inulinus and its SCS both dramatically decrease the adhesion of S. enteritidis to Caco-2 cells; meanwhile, the SCS of S. inulinus vegetative cells inhibited the growth of S. enteritidis in the inhibition zone test. The existing inhibition factor could be assumed to be lactic acid in the SCS. From the results of the invasion assay, S. inulinus showed high safety properties. In conclusion, based on these in vitro evaluations, results suggest that S. inulinus presents probiotic features of great potential in the vegetative cell form.
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Affiliation(s)
- Hui-Ying Huang
- Department of Nutrition, China Medical University, Taichung, 404 Taiwan, ROC
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28
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Kurdi P, Kawanishi K, Mizutani K, Yokota A. Mechanism of growth inhibition by free bile acids in lactobacilli and bifidobacteria. J Bacteriol 2006; 188:1979-86. [PMID: 16484210 PMCID: PMC1426545 DOI: 10.1128/jb.188.5.1979-1986.2006] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The effects of the free bile acids (FBAs) cholic acid (CA), deoxycholic acid (DCA), and chenodeoxycholic acid on the bioenergetics and growth of lactobacilli and bifidobacteria were investigated. It was found that these FBAs reduced the internal pH levels of these bacteria with rapid and stepwise kinetics and, at certain concentrations, dissipated DeltapH. The bile acid concentrations that dissipated DeltapH corresponded with the MICs for the selected bacteria. Unlike acetate, propionate, and butyrate, FBAs dissipated the transmembrane electrical potential (DeltaPsi). In Bifidobacterium breve JCM 1192, the synthetic proton conductor pentachlorophenol (PCP) dissipated DeltapH with a slow and continuous kinetics at a much lower concentration than FBAs did, suggesting the difference in mode of action between FBAs and true proton conductors. Membrane damage assessed by the fluorescence method and a viability decrease were also observed upon exposure to CA or DCA at the MIC but not to PCP or a short-chain fatty acid mixture. Loss of potassium ion was observed at CA concentrations more than 2 mM (0.4x MIC), while leakage of other cellular components increased at CA concentrations more than 4 mM (0.8 x MIC). Additionally, in experiments with membrane phospholipid vesicles extracted from Lactobacillus salivarius subsp. salicinius JCM 1044, CA and DCA at the MIC collapsed the DeltapH with concomitant leakage of intravesicular fluorescent pH probe, while they did not show proton conductance at a lower concentration range (e.g., 0.2x MIC). Taking these observations together, we conclude that FBAs at the MIC disturb membrane integrity and that this effect can lead to leakage of proton (membrane DeltapH and DeltaPsi dissipation), potassium ion, and other cellular components and eventually cell death.
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Affiliation(s)
- Peter Kurdi
- Laboratory of Microbial Resources and Ecology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
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Diez-Gonzalez F, Russell JB. Effects of carbonylcyanide-m-chlorophenylhydrazone (CCCP) and acetate on Escherichia coli O157:H7 and K-12: uncoupling versus anion accumulation. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1997.tb10396.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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30
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Flythe MD, Russell JB. The ability of acidic pH, growth inhibitors, and glucose to increase the proton motive force and energy spilling of amino acid-fermenting Clostridium sporogenes MD1 cultures. Arch Microbiol 2005; 183:236-42. [PMID: 15891933 DOI: 10.1007/s00203-005-0765-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 02/07/2005] [Accepted: 02/08/2005] [Indexed: 10/25/2022]
Abstract
Clostridium sporogenes MD1 grew rapidly with peptides and amino acids as an energy source at pH 6.7. However, the proton motive force (Deltap) was only -25 mV, and protonophores did not inhibit growth. When extracellular pH was decreased with HCl, the chemical gradient of protons (ZDeltapH) and the electrical membrane potential (DeltaPsi) increased. The Deltap was -125 mV at pH 4.7, even though growth was not observed. At pH 6.7, glucose addition did not cause an increase in growth rate, but DeltaPsi increased to -70 mV. Protein synthesis inhibitors also significantly increased DeltaPsi. Non-growing, arginine-energized cells had a DeltaPsi of -80 mV at pH 6.7 or pH 4.7, but DeltaPsi was not detected if the F1F0 ATPase was inhibited. Arginine-energized cells initiated growth if other amino acids were added at pH 6.7, and DeltaPsi and ATP declined. At pH 4.7, ATP production remained high. However, growth could not be initiated, and neither DeltaPsi nor the intracellular ATP concentration declined. Based on these results, it appears that C. sporogenes MD1 does not need a large Deltap to grow, and Deltap appears to serve as a mechanism of ATP dissipation or energy spilling.
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Affiliation(s)
- Michael D Flythe
- Department of Microbiology, Cornell University, Wing Hall, Ithaca, NY 14853, USA
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31
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Ghali MB, Scott PT, Al Jassim RAM. Characterization of Streptococcus bovis from the rumen of the dromedary camel and Rusa deer. Lett Appl Microbiol 2004; 39:341-6. [PMID: 15355536 DOI: 10.1111/j.1472-765x.2004.01597.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Isolation and characterization of Streptococcus bovis from the dromedary camel and Rusa deer. METHODS AND RESULTS Bacteria were isolated from the rumen contents of four camels and two deer fed lucerne hay by culturing on the semi-selective medium MRS agar. Based on Gram morphology and RFLP analysis seven isolates, MPR1, MPR2, MPR3, MPR4, MPR5, RD09 and RD11 were selected and putatively identified as Streptococcus. The identity of these isolates was later confirmed by comparative DNA sequence analysis of the 16S rRNA gene with the homologous sequence from S. bovis strains, JB1, C14b1, NCFB2476, SbR1, SbR7 and Sb5, from cattle and sheep, and the Streptococcus equinus strain NCD01037T. The percentage similarity amongst all strains was >99%, confirming the identification of the camel isolates as S. bovis. The strains were further characterized by their ability to utilize a range of carbohydrates, the production of volatile fatty acids (VFA) and lactate and the determination of the doubling time in basal medium 10 supplemented with glucose. All the isolates produced l-lactate as a major fermentation end product, while four of five camel isolates produced VFA. The range of carbohydrates utilized by all the strains tested, including those from cattle and sheep were identical, except that all camel isolates and the deer isolate RD11 were additionally able to utilize arabinose. CONCLUSIONS Streptococcus bovis was successfully isolated from the rumen of camels and deer, and shown by molecular and biochemical characterization to be almost identical to S. bovis isolates from cattle and sheep. SIGNIFICANCE AND IMPACT OF THE STUDY Streptococcus bovis is considered a key lactic acid producing bacterium from the gastrointestinal tract of ruminants, and has been implicated as a causative agent of lactic acidosis. This study is the first report of the isolation and characterization of S. bovis from the dromedary camel and Rusa deer, and suggests a major contributive role of this bacterium to fermentative acidosis.
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Affiliation(s)
- M B Ghali
- School of Animal Studies, The University of Queensland, Galton, QLD, Australia
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Asahara T, Shimizu K, Nomoto K, Hamabata T, Ozawa A, Takeda Y. Probiotic bifidobacteria protect mice from lethal infection with Shiga toxin-producing Escherichia coli O157:H7. Infect Immun 2004; 72:2240-7. [PMID: 15039348 PMCID: PMC375161 DOI: 10.1128/iai.72.4.2240-2247.2004] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The anti-infectious activity of probiotic Bifidobacteria against Shiga toxin-producing Escherichia coli (STEC) O157:H7 was examined in a fatal mouse STEC infection model. Stable colonization of the murine intestines was achieved by the oral administration of Bifidobacterium breve strain Yakult (naturally resistant to streptomycin sulfate) as long as the mice were treated with streptomycin in their drinking water (5 mg/ml). The pathogenicity of STEC infection, characterized by marked body weight loss and subsequent death, observed in the infected controls was dramatically inhibited in the B. breve-colonized group. Moreover, Stx production by STEC cells in the intestine was almost completely inhibited in the B. breve-colonized group. A comparison of anti-STEC activity among several Bifidobacterium strains with natural resistance to streptomycin revealed that strains such as Bifidobacterium bifidum ATCC 15696 and Bifidobacterium catenulatum ATCC 27539(T) did not confer an anti-infectious activity, despite achieving high population levels similar to those of effective strains, such as B. breve strain Yakult and Bifidobacterium pseudocatenulatum DSM 20439. The effective strains produced a high concentration of acetic acid (56 mM) and lowered the pH of the intestine (to pH 6.75) compared to the infected control group (acetic acid concentration, 28 mM; pH, 7.15); these effects were thought to be related to the anti-infectious activity of these strains because the combination of a high concentration of acetic acid and a low pH was found to inhibit Stx production during STEC growth in vitro.
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Affiliation(s)
- Takashi Asahara
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo 186-8650, Japan
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Kurdi P, Tanaka H, van Veen HW, Asano K, Tomita F, Yokota A. Cholic acid accumulation and its diminution by short-chain fatty acids in bifidobacteria. MICROBIOLOGY (READING, ENGLAND) 2003; 149:2031-2037. [PMID: 12904543 DOI: 10.1099/mic.0.26376-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cholic acid (CA) transport was investigated in nine intestinal Bifidobacterium strains. Upon energization with glucose, all of the bifidobacteria accumulated CA. The driving force behind CA accumulation was found to be the transmembrane proton gradient (Delta pH, alkaline interior). The levels of accumulated CA generally coincided with the theoretical values, which were calculated by the Henderson-Hasselbalch equation using the measured internal pH values of the bifidobacteria, and a pK(a) value of 6.4 for CA. These results suggest that the mechanism of CA accumulation is based on the diffusion of a hydrophobic weak acid across the bacterial cell membrane, and its dissociation according to the Delta pH value. A mixture of short-chain fatty acids (acetate, propionate and butyrate) at the appropriate colonic concentration (117 mM in total) reduced CA accumulation in Bifidobacterium breve JCM 1192(T). These short-chain fatty acids, which are weak acids, reduced the Delta pH, thereby decreasing CA accumulation in a dose-dependent manner. The bifidobacteria did not alter or modify the CA molecule. The probiotic potential of CA accumulation in vivo is discussed in relation to human bile acid metabolism.
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Affiliation(s)
- Peter Kurdi
- Northern Advancement Center for Science & Technology, Kita 7 Nishi 2, Kita-ku, Sapporo 060-0807, Japan
| | - Hiroshi Tanaka
- Snow Brand Milk Products Co., Ltd, 1-1-2, Minamidai, Kawagoe 350-1165, Japan
| | - Hendrik W van Veen
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9751 NN Haren, The Netherlands
| | - Kozo Asano
- Laboratory of Applied Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan
| | - Fusao Tomita
- Laboratory of Applied Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan
| | - Atsushi Yokota
- Laboratory of Microbial Resources and Ecology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan
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ASANUMA N, HINO T. Regulation of fermentation in a ruminal bacterium,Streptococcus bovis, with special reference to rumen acidosis. Anim Sci J 2002. [DOI: 10.1046/j.1344-3941.2002.00044.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gäbel G, Aschenbach JR, Müller F. Transfer of energy substrates across the ruminal epithelium: implications and limitations. Anim Health Res Rev 2002; 3:15-30. [PMID: 12400867 DOI: 10.1079/ahrr200237] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ruminal epithelium has an enormous capacity for the absorption of short-chain fatty acids (SCFAs). This not only delivers metabolic energy to the animal but is also an essential regulatory mechanism that stabilizes the intraruminal milieu. The epithelium itself, however, is endangered by the influx of SCFAs because the intracellular pH (pHi) may drop to a lethal level. To prevent severe cytosolic acidosis, the ruminal epithelium is able to extrude (or buffer) protons by various mechanisms: (i) a Na+/H+ exchanger, (ii) a bicarbonate importing system and (iii) an H+/monocarboxylate cotransporter (MCT). Besides pHi regulation, the MCT also provides the animal with ketone bodies derived from the intraepithelial breakdown of SCFAs. Ketone bodies, in turn, can serve as an energy source for extrahepatic tissues. In addition to SCFA uptake, glucose absorption has recently been identified as a potential way of eliminating acidogenic substrates from the rumen. At least with respect to SCFAs, absorption rates can be elevated when adapting animals to energy-rich diets. Although they are very effective under physiological conditions, the absorptive and regulatory mechanisms of the ruminal epithelium also have their limits. An increased number of protons during the state of ruminal acidosis can be eliminated neither from the lumen nor the cytosol, thus worsening dysfermentation and finally leading to functional and morphological alterations of the epithelial lining.
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Affiliation(s)
- G Gäbel
- Veterinär-Physiologisches Institut, Universität Leipzig, Germany.
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Asahara T, Nomoto K, Shimizu K, Watanuki M, Tanaka R. Increased resistance of mice to Salmonella enterica serovar Typhimurium infection by synbiotic administration of Bifidobacteria and transgalactosylated oligosaccharides. J Appl Microbiol 2001; 91:985-96. [PMID: 11851805 DOI: 10.1046/j.1365-2672.2001.01461.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIMS The anti-infectious activity of Bifidobacteria in combination with transgalactosylated oligosaccharides (TOS) against Salmonella enterica serovar Typhimurium LT-2 in an opportunistic antibiotic-induced murine infection model in mice was examined. METHODS AND RESULTS B. breve (strain Yakult) with natural resistance to streptomycin sulphate (SM, MIC: > 4 mg ml(-1)), when given daily at a dose of 108 cfu/mouse orally under SM treatment was constantly excreted at 10(10) cfu g(-1) faeces so long as SM was administered, even at 2 weeks after discontinuing administration of B. breve. Explosive intestinal growth and subsequent extra-intestinal translocation of orally infected LT-2 under SM treatment were inhibited by B. breve colonization, and this anti-infectious activity was strengthened by synbiotic administration of TOS with B. breve. Comparison of anti-Salmonella activity among several Bifidobacterium strains with natural resistance to SM revealed that strains such as B. bifidum ATCC 15696 and B. catenulatum ATCC 27539T conferred no activity, even when they reached high population levels similar those of effective strains such as strain Yakult and B. pseudocatenulatum DSM 20439. Both the increase in the concentration of organic acids and the lowered pH in the intestine due to bifidobacterial colonization correlated with the anti-infectious activity. Moreover, the crude cecal extract of B. breve-colonized mice exerted growth-inhibitory activity against LT-2 in vitro, whereas that of the ineffective B. bifidum-colonized cecum showed much lower activity. CONCLUSIONS Intestinal colonization by bifidobacteria given exogenously together with TOS during antibiotic treatment prevents the antibiotic-induced disruption of colonization resistance to oral infection with S. enterica serovar Typhimurium, and the metabolic activity needed to produce organic acids and lower the intestinal pH is important in the anti-infectious activity of synbiotics against enteric infection with Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY These results indicate that certain bifidobacteria together with prebiotics may be used for the prophylaxis against opportunistic intestinal infections with antibiotic-resistant pathogens.
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Affiliation(s)
- T Asahara
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan.
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Ogawa M, Shimizu K, Nomoto K, Tanaka R, Hamabata T, Yamasaki S, Takeda T, Takeda Y. Inhibition of in vitro growth of Shiga toxin-producing Escherichia coli O157:H7 by probiotic Lactobacillus strains due to production of lactic acid. Int J Food Microbiol 2001; 68:135-40. [PMID: 11545213 DOI: 10.1016/s0168-1605(01)00465-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The inhibiting characteristics of lactic acid bacteria on Shiga toxin-producing Escherichia coli (STEC) O157:H7 (three strains, clinically isolated) was investigated by using a batch fermentation system. The species such as Lactobacillus casei strain Shirota or L. acidophilus YIT 0070 exert growth inhibitory and bactericidal activities on STEC. The pH value and undissociated lactic acid (U-LA) concentration of the culture medium of STEC cocultured with L. casei or L. acidophilus dramatically lowered or increased, respectively [corrected], when compared with those of the control culture. The cytotoxic properties of U-LA on STEC strain 89020087 analyzed in vitro was divided into two phases, i.e., the bacteriostatic phase (between 3.2 to 62 mM) and the bactericidal phase (over 62 mM). These data suggest that the bactericidal effect of Lactobacillus on STEC depends on its lactic acid production and pH reductive effect.
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Affiliation(s)
- M Ogawa
- Yakult Central Institute for Microbiologial Research, Kunitachi, Tokyo, Japan
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Abstract
Anaerobic habitats often have low pH and high concentrations of fermentation acids, and these conditions can inhibit the growth of many bacteria. The toxicity of fermentation acids at low pH was traditionally explained by an uncoupling mechanism. Undissociated fermentation acids can pass across the cell membrane and dissociate in the more alkaline interior, but there is little evidence that they can act in a cyclic manner to dissipate protonmotive force. Fermentation acid dissociation in the more alkaline interior causes an accumulation of the anionic species, and this accumulation is dependent on the pH gradient (delta pH) across the membrane. Fermentation acid-resistant bacteria have low delta pH and are able to generate ATP and grow with a low intracellular pH. Escherichia coli O157:H7 is able to decrease its intracellular pH to 6.1 before growth ceases, but this modest decrease in delta pH can only partially counteract the toxic effect of fermentation anion accumulation. Fermentation acid-resistant bacteria are in most cases Gram-positive bacteria with a high intracellular potassium concentration, and even acid-sensitive bacteria like E. coli K-12 have increased potassium levels when fermentation acids are present. Intracellular potassium provides a counteraction for fermentation acid anions, and allows bacteria to tolerate even greater amounts of fermentation anions. The delta pH-mediated anion accumulation provides a mechanistic explanation for the effect of fermentation acids on microbial ecology and metabolism.
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Affiliation(s)
- J B Russell
- Section of Microbiology, Cornell University, USDA Ithaca, New York 14853, USA
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Diez-Gonzalez F, Russell JB. The ability of Escherichia coli O157:H7 to decrease its intracellular pH and resist the toxicity of acetic acid. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 4):1175-1180. [PMID: 9141680 DOI: 10.1099/00221287-143-4-1175] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Batch cultures of Escherichia coli K-12 grew well in an anaerobic glucose medium at pH 5.9, but even small amounts of acetate (20 mM) inhibited growth and fermentation. E. coli O157:H7 was at least fourfold more resistant to acetate than K-12. Continuous cultures of E. coli K-12 (pH 5.9, dilution rate 0.085 h-1) did not wash out until the sodium acetate concentration in the input medium was 80 mM, whereas E. coli O157:H7 persisted until the sodium acetate concentration was 160 mM. E. coli K-12 cell accumulated as much as 500 mM acetate, but the intracellular acetate concentration of O157:H7 was never greater than 300 mM. Differences in acetate accumulation could be explained by intracellular pH and the transmembrane pH gradient (delta pH). E. coli K-12 maintained a more or less constant delta pH (intracellular pH 6.8), but E. coli O157:H7 let its delta pH decrease from 0.9 to 0.2 units as sodium acetate was added to the medium. Sodium acetate increased the rate of glucose consumption, but there was little evidence to support the idea that acetate was creating a futile cycle of protons. Increases in glucose consumption rate could be explained by increases in D-lactate production and decreases in ATP production. Intracellular acetate was initially lower than the amount predicted by delta pH, but intracellular acetate and delta pH were in equilibrium when the external acetate concentrations were high. Based on these results, the acetate tolerance of O157:H7 can be explained by fundamental differences in metabolism and intracellular pH regulation. By decreasing the intracellular pH and producing large amounts of D-lactate, O157:H7 is able to decrease delta pH and prevent toxic accumulations of intracellular acetate anion.
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Affiliation(s)
| | - James B Russell
- Agricultural Research Service, USDA, Ithaca, NY 14853, USA
- Section of Microbiology, Cornell University, Ithaca, NY 14853, USA
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Abstract
Dental biofilms could have a structure which, in sections, looks like tissue. The internal structure of the dental biofilm could be the result of interbacterial adhesion mechanisms in combination with nutritional conditions characterized by multiple nutrient starvation. The preservation of the structure of the biofilm over time may also involve the ability of the bacteria to withstand environmental stresses such as starvation, reactive oxygen products, and acid. The present review will describe, first, the regulation of the metabolic defense against environmental stresses and then focus mainly on the energy metabolism of dental biofilms.
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Affiliation(s)
- J Carlsson
- Department of Oral Biology, Umeå University, Sweden
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Carlsson J, Hamilton IR. Differential toxic effects of lactate and acetate on the metabolism of Streptococcus mutans and Streptococcus sanguis. ORAL MICROBIOLOGY AND IMMUNOLOGY 1996; 11:412-9. [PMID: 9467375 DOI: 10.1111/j.1399-302x.1996.tb00204.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Experiments were conducted with Streptococcus mutans NCTC 10449 and Streptococcus sanguis ATCC 10556 to determine whether the acid end-products, lactate and acetate, were involved in the regulation of cellular growth and metabolism. The growth rate and culture biomass of both organisms was inhibited by the addition of lactate and acetate at concentrations as high as 200 mM to the cultures, although the final pH values of the lactate and acetate cultures were similar. In addition, the metabolic conversion of glucose to lactate was decreased by external lactate but stimulated by acetate. In spite of this, calculation of the yield of cell biomass per mole of ATP (YATP) showed that the yield of both organisms actually increased in the presence of added lactate, but decreased with acetate. This indicates that the two acids interacted with the cells of the organisms by different mechanisms. For both organisms, the final external undissociated lactic acid was relatively constant at concentrations between 0 and 200 mM added lactate, 24.9-32.5 mM for S. mutans and 8.0-11.5 mM for S. sanguis. On the other hand, the final concentration of undissociated acetic acid in the S. mutans cultures increased from 2.9 to 83.7 mM as the medium acetate concentration increased, and from 1.0 to 36.0 mM with the S. sanguis cultures. Counterflow experiments provided evidence for a lactate carrier in both S. mutans and S. sanguis, but an acetate carrier in these organisms could not be demonstrated. [14C]-lactate and [14C]-acetate were taken up into de-energized, chemostatgrown cells of S. mutans and S. sanguis in response to an artificially generated pH gradient but not by an imposed electrical gradient. Thus, under these conditions lactate uptake occurred via a symport process with only one proton. Growth of both organisms in the presence of increasing concentrations of acetate resulted in a small reduction (27%) in the transmembrane pH gradient (delta pH) as measured by the permeant acid, [14C]-salicylate. However, the uptake of [14C]-acetate for the estimation of delta pH revealed significant inhibition of the acetate concentration gradient in the presence external acetate, indicating that the cells expelled the acetate anion. The results indicate that, unlike acetate uptake, lactate transport by S. mutans and S. sanguis was strictly regulated via the lactate carrier in order to prevent excessive dissipation of the pH gradient. Clearly, the formation of acetate by oral streptococci is more problematic for cellular homeostasis than the formation of lactate.
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Affiliation(s)
- J Carlsson
- Department of Oral Microbiology, University of Umeå, Sweden
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Abstract
Ruminant animals depend on cellulolytic ruminal bacteria to digest cellulose, but these bacteria cannot resist the low ruminal pH that modern feeding practices can create. Because the cellulolytic bacteria cannot grow on cellobiose at low pH, pH sensitivity is a general aspect of growth and not just a limitation of the cellulases per se. Acid-resistant ruminal bacteria have evolved the capacity to let their intracellular pH decrease, maintain a small pH gradient across the cell membrane, and prevent an intracellular accumulation of VFA anions. Cellulolytic bacteria cannot grow with a low intracellular pH, and an increase in pH gradient leads to anion toxicity. Prevotella ruminicola cannot digest native cellulose, but it grows at low pH and degrades the cellulose derivative, carboxymethylcellulose. The Prevotella ruminicola carboxymethylcellulase cannot bind to cellulose, but a recombinant enzyme having the Prevotella ruminicola catalytic domain and a binding domain from Thermomonspora fusca was able to bind and had cellulase activity that was at least 10-fold higher. Based on these results, gene reconstruction offers a means of converting Prevotella ruminicola into a ruminal bacterium that can digest cellulose at low pH.
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Affiliation(s)
- J B Russell
- Agricultural Research Service, USDA, Cornell University, Ithaca, NY 14853, USA
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Kleman GL, Strohl WR. Acetate metabolism by Escherichia coli in high-cell-density fermentation. Appl Environ Microbiol 1994; 60:3952-8. [PMID: 7993084 PMCID: PMC201921 DOI: 10.1128/aem.60.11.3952-3958.1994] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Little is known about the cellular physiology of Escherichia coli at high cell densities (e.g., greater than 50 g [dry cell weight] per liter), particularly in relation to the cellular response to different growth conditions. E. coli W3100 cultures were grown under identical physical and nutritional conditions, by using a computer-controlled fermentation system which maintains the glucose concentration at 0.5 g/liter, to high cell densities at pH values of 6.0, 6.5, 7.0, and 7.5. The data suggest a relationship between the pH of the environment and the amount of acetate excreted by the organism during growth. At pH values of 6.0 and 6.5, the acetate reached a concentration of 6 g/liter, whereas at pH 7.5, the acetate reached a concentration of 12 g/liter. Furthermore, at pH values of 6.0 to 7.0, the E. coli culture undergoes a dramatic metabolic switch in which oxygen and glucose consumption and CO2 evolution all temporarily decreased by 50 to 80%, with a concomitant initiation of acetate utilization. After a 30-min pause in which approximately 50% of the available acetate is consumed, the culture recovers and resumes consuming glucose and oxygen and producing acetate and CO2 at preswitch levels. During the switch period, the specific activity of isocitrate lyase typically increases approximately fourfold.
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Affiliation(s)
- G L Kleman
- Department of Microbiology, Ohio State University, Columbus 43210
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Rius NÃ, Solé M, Francia A, Lorén JG. Buffering capacity and membrane H+conductance of lactic acid bacteria. FEMS Microbiol Lett 1994. [DOI: 10.1111/j.1574-6968.1994.tb07048.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Cook GM, Russell JB. The effect of extracellular pH and lactic acid on pH homeostasis inLactococcus lactis andStreptococcus bovis. Curr Microbiol 1994. [DOI: 10.1007/bf01571059] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells.
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Affiliation(s)
- J B Russell
- Agricultural Research Service, Cornell University, Ithaca, New York 14853
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