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Abou Mourad Ferreira M, Candeias Dos Santos L, Schmidt Castellani LG, Negrelli Brunetti M, Palaci M. Application of BactTiter-Glo ATP bioluminescence assay for Mycobacterium tuberculosis detection. Diagn Microbiol Infect Dis 2024; 109:116275. [PMID: 38537505 DOI: 10.1016/j.diagmicrobio.2024.116275] [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: 10/06/2023] [Revised: 03/12/2024] [Accepted: 03/16/2024] [Indexed: 04/30/2024]
Abstract
BACKGROUND Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains a global health threat, necessitating faster and more accessible diagnostic methods. This study investigates critical parameters in the application of a commercial ATP bioluminescence assay for the detection of MTB. METHOD Our objective was to optimize the ATP bioluminescence protocol using BacTiter-Glo™ for MTB, investigating the impact of varying volumes of MTB suspension and reagent on assay sensitivity, evaluating ATP extraction methods, establishing calibration curves, and elucidating strain-specific responses to antimicrobial agents. RESULTS ATP extraction methods showed no significant improvement over controls. Calibration curves revealed a linear correlation between relative light units (RLU) and colony-forming units (CFU/mL), establishing low detection limits. Antimicrobial testing demonstrated strain-specific responses aligning with susceptibility and resistance patterns. CONCLUSION Our findings contribute to refining ATP bioluminescence protocols for enhanced MTB detection and susceptibility testing. Further refinements and validation efforts are warranted, holding promise for more efficient diagnostic platforms in the future.
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Affiliation(s)
- Mariana Abou Mourad Ferreira
- Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde (Health Sciences Center), Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, 29040-090 Vitória, Espírito Santo, Brazil.
| | - Laura Candeias Dos Santos
- Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde (Health Sciences Center), Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, 29040-090 Vitória, Espírito Santo, Brazil
| | - Luiz Guilherme Schmidt Castellani
- Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde (Health Sciences Center), Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, 29040-090 Vitória, Espírito Santo, Brazil
| | - Manuela Negrelli Brunetti
- Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde (Health Sciences Center), Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, 29040-090 Vitória, Espírito Santo, Brazil
| | - Moisés Palaci
- Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde (Health Sciences Center), Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, 29040-090 Vitória, Espírito Santo, Brazil
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2
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Hernandez DM, Marzouk M, Cole M, Fortoul MC, Kethireddy SR, Contractor R, Islam H, Moulder T, Kalifa AR, Meneses EM, Mendoza MB, Thomas R, Masud S, Pubien S, Milanes P, Diaz-Tang G, Lopatkin AJ, Smith RP. Purine and pyrimidine synthesis differently affect the strength of the inoculum effect for aminoglycoside and β-lactam antibiotics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.09.588696. [PMID: 38645041 PMCID: PMC11030397 DOI: 10.1101/2024.04.09.588696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The inoculum effect has been observed for nearly all antibiotics and bacterial species. However, explanations accounting for its occurrence and strength are lacking. We previously found that growth productivity, which captures the relationship between [ATP] and growth, can account for the strength of the inoculum effect for bactericidal antibiotics. However, the molecular pathway(s) underlying this relationship, and therefore determining the inoculum effect, remain undiscovered. We show that nucleotide synthesis can determine the relationship between [ATP] and growth, and thus the strength of inoculum effect in an antibiotic class-dependent manner. Specifically, and separate from activity through the tricarboxylic acid cycle, we find that transcriptional activity of genes involved in purine and pyrimidine synthesis can predict the strength of the inoculum effect for β-lactam and aminoglycosides antibiotics, respectively. Our work highlights the antibiotic class-specific effect of purine and pyrimidine synthesis on the severity of the inoculum effect and paves the way for intervention strategies to reduce the inoculum effect in the clinic.
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Affiliation(s)
- Daniella M. Hernandez
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Melissa Marzouk
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Madeline Cole
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Marla C. Fortoul
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Saipranavi Reddy Kethireddy
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Rehan Contractor
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Habibul Islam
- Department of Chemical Engineering, University of Rochester; Rochester, NY 14627; USA
| | - Trent Moulder
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Ariane R. Kalifa
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Estefania Marin Meneses
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Maximiliano Barbosa Mendoza
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Ruth Thomas
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Saad Masud
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Sheena Pubien
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Patricia Milanes
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Gabriela Diaz-Tang
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL, 33314
| | - Allison J. Lopatkin
- Department of Chemical Engineering, University of Rochester; Rochester, NY 14627; USA
- Department of Microbiology and Immunology, University of Rochester Medical Center; Rochester, NY 14627; USA
- Department of Biomedical Engineering, University of Rochester Medical Center; Rochester, NY 14627; USA
| | - Robert P. Smith
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
- Department of Medical Education, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314
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3
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Jia Z, Luo Y, Wang D, Holliday E, Sharma A, Green MM, Roche MR, Thompson-Witrick K, Flock G, Pearlstein AJ, Yu H, Zhang B. Surveillance of pathogenic bacteria on a food matrix using machine-learning-enabled paper chromogenic arrays. Biosens Bioelectron 2024; 248:115999. [PMID: 38183791 DOI: 10.1016/j.bios.2024.115999] [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: 10/12/2023] [Revised: 12/26/2023] [Accepted: 01/01/2024] [Indexed: 01/08/2024]
Abstract
Global food systems can benefit significantly from continuous monitoring of microbial food safety, a task for which tedious operations, destructive sampling, and the inability to monitor multiple pathogens remain challenging. This study reports significant improvements to a paper chromogenic array sensor - machine learning (PCA-ML) methodology sensing concentrations of volatile organic compounds (VOCs) emitted on a species-specific basis by pathogens by streamlining dye selection, sensor fabrication, database construction, and machine learning and validation. This approach enables noncontact, time-dependent, simultaneous monitoring of multiple pathogens (Listeria monocytogenes, Salmonella, and E. coli O157:H7) at levels as low as 1 log CFU/g with over 90% accuracy. The report provides theoretical and practical frameworks demonstrating that chromogenic response, including limits of detection, depends on time integrals of VOC concentrations. The paper also discusses the potential for implementing PCA-ML in the food supply chain for different food matrices and pathogens, with species- and strain-specific identification.
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Affiliation(s)
- Zhen Jia
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, 32611, USA
| | - Yaguang Luo
- Environmental Microbial and Food Safety Lab and Food Quality Lab, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD, 20705, USA
| | - Dayang Wang
- Department of Electrical and Computer Engineering, University of Massachusetts, Lowell, MA, 01854, USA
| | - Emma Holliday
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, 32611, USA
| | - Arnav Sharma
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, 32611, USA; School of Medicine, Duke University, Durham, NC, 27710, USA
| | - Madison M Green
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, 01854, USA
| | - Michelle R Roche
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, 01854, USA
| | | | - Genevieve Flock
- US Army Natick Soldier Research, Development, and Engineering Center, Natick, MA, 01760, USA
| | - Arne J Pearlstein
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Hengyong Yu
- Department of Electrical and Computer Engineering, University of Massachusetts, Lowell, MA, 01854, USA
| | - Boce Zhang
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, 32611, USA.
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4
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Bannenberg JW, Boeren S, Zwietering MH, Abee T, den Besten HMW. Insight in lag phase of Listeria monocytogenes during enrichment through proteomic and transcriptomic responses. Food Res Int 2024; 175:113609. [PMID: 38128973 DOI: 10.1016/j.foodres.2023.113609] [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: 06/06/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
The dynamics of the enrichment-based detection procedure of the foodborne pathogen Listeria monocytogenes from food still remains poorly understood. This enrichment is crucial in the reliable detection of this pathogen and more insight into the recovery mechanism during this step is important to advance our understanding of lag phase behaviour during enrichment. In this study we combined transcriptomic and proteomic analyses to better understand the physiological processes within the lag phase of L. monocytogenes during enrichment. Upon transfer of BHI-cultured stationary phase L. monocytogenes cells to half-Fraser enrichment broth (HFB), motility-associated genes and proteins were downregulated, while expression of metal uptake transporters, resuscitation-promoting factors that stimulate growth from dormancy, antibiotic efflux pumps and oxidative stress proteins were upregulated. Next to this, when cells with a heat stress history were cultured in enrichment broth, proteins necessary for recovery were upregulated with functions in DNA-damage repair, protein refolding, cell-wall repair, and zinc transport. Proteomic results pointed to possible factors that support shortening the lag duration, including the addition of 10 µM zinc and the addition of spent HFB containing presumed concentrations of resuscitation-promoting factors. However, these interventions did not lead to biologically relevant reduction of lag phase. Also, when cells were enriched in spent HFB, final cell concentrations were similar to enrichments in fresh HFB, indicating that the enrichment broth seems not to lack critical substrates. Concludingly, this study gives insight into the proteomic changes in the lag phase during enrichment and shows that supplementation of HFB is not the best strategy to optimize the current enrichment method.
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Affiliation(s)
- Jasper W Bannenberg
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Marcel H Zwietering
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
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5
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Accelerated Adaptive Laboratory Evolution by Automated Repeated Batch Processes in Parallelized Bioreactors. Microorganisms 2023; 11:microorganisms11020275. [PMID: 36838240 PMCID: PMC9965177 DOI: 10.3390/microorganisms11020275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/26/2023] Open
Abstract
Adaptive laboratory evolution (ALE) is a valuable complementary tool for modern strain development. Insights from ALE experiments enable the improvement of microbial cell factories regarding the growth rate and substrate utilization, among others. Most ALE experiments are conducted by serial passaging, a method that involves large amounts of repetitive manual labor and comes with inherent experimental design flaws. The acquisition of meaningful and reliable process data is a burdensome task and is often undervalued and neglected, but also unfeasible in shake flask experiments due to technical limitations. Some of these limitations are alleviated by emerging automated ALE methods on the μL and mL scale. A novel approach to conducting ALE experiments is described that is faster and more efficient than previously used methods. The conventional shake flask approach was translated to a parallelized, L scale stirred-tank bioreactor system that runs controlled, automated, repeated batch processes. The method was validated with a growth optimization experiment of E. coli K-12 MG1655 grown with glycerol minimal media as a benchmark. Off-gas analysis enables the continuous estimation of the biomass concentration and growth rate using a black-box model based on first principles (soft sensor). The proposed method led to the same stable growth rates of E. coli with the non-native carbon source glycerol 9.4 times faster than the traditional manual approach with serial passaging in uncontrolled shake flasks and 3.6 times faster than an automated approach on the mL scale. Furthermore, it is shown that the cumulative number of cell divisions (CCD) alone is not a suitable timescale for measuring and comparing evolutionary progress.
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6
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Mononen T, Kuosmanen T, Cairns J, Mustonen V. Understanding cellular growth strategies via optimal control. J R Soc Interface 2023; 20:20220744. [PMID: 36596459 PMCID: PMC9810423 DOI: 10.1098/rsif.2022.0744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Evolutionary prediction and control are increasingly interesting research topics that are expanding to new areas of application. Unravelling and anticipating successful adaptations to different selection pressures becomes crucial when steering rapidly evolving cancer or microbial populations towards a chosen target. Here we introduce and apply a rich theoretical framework of optimal control to understand adaptive use of traits, which in turn allows eco-evolutionarily informed population control. Using adaptive metabolism and microbial experimental evolution as a case study, we show how demographic stochasticity alone can lead to lag time evolution, which appears as an emergent property in our model. We further show that the cycle length used in serial transfer experiments has practical importance as it may cause unintentional selection for specific growth strategies and lag times. Finally, we show how frequency-dependent selection can be incorporated to the state-dependent optimal control framework allowing the modelling of complex eco-evolutionary dynamics. Our study demonstrates the utility of optimal control theory in elucidating organismal adaptations and the intrinsic decision making of cellular communities with high adaptive potential.
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Affiliation(s)
- Tommi Mononen
- Department of Computer Science, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki 00014, Finland
| | - Teemu Kuosmanen
- Department of Computer Science, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki 00014, Finland
| | - Johannes Cairns
- Department of Computer Science, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki 00014, Finland
| | - Ville Mustonen
- Department of Computer Science, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki 00014, Finland,Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
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7
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Diaz-Tang G, Meneses EM, Patel K, Mirkin S, García-Diéguez L, Pajon C, Barraza I, Patel V, Ghali H, Tracey AP, Blanar CA, Lopatkin AJ, Smith RP. Growth productivity as a determinant of the inoculum effect for bactericidal antibiotics. SCIENCE ADVANCES 2022; 8:eadd0924. [PMID: 36516248 PMCID: PMC9750144 DOI: 10.1126/sciadv.add0924] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 11/11/2022] [Indexed: 06/10/2023]
Abstract
Understanding the mechanisms by which populations of bacteria resist antibiotics has implications in evolution, microbial ecology, and public health. The inoculum effect (IE), where antibiotic efficacy declines as the density of a bacterial population increases, has been observed for multiple bacterial species and antibiotics. Several mechanisms to account for IE have been proposed, but most lack experimental evidence or cannot explain IE for multiple antibiotics. We show that growth productivity, the combined effect of growth and metabolism, can account for IE for multiple bactericidal antibiotics and bacterial species. Guided by flux balance analysis and whole-genome modeling, we show that the carbon source supplied in the growth medium determines growth productivity. If growth productivity is sufficiently high, IE is eliminated. Our results may lead to approaches to reduce IE in the clinic, help standardize the analysis of antibiotics, and further our understanding of how bacteria evolve resistance.
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Affiliation(s)
- Gabriela Diaz-Tang
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Estefania Marin Meneses
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Kavish Patel
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Sophia Mirkin
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Laura García-Diéguez
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Camryn Pajon
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Ivana Barraza
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Vijay Patel
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Helana Ghali
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Angelica P. Tracey
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Christopher A. Blanar
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
| | - Allison J. Lopatkin
- Department of Biology, Barnard College, Columbia University, New York, NY10025, USA
- Data Science Institute, Columbia University, New York, NY10025, USA
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY10025, USA
| | - Robert P. Smith
- Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
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8
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Ardré M, Doulcier G, Brenner N, Rainey PB. A leader cell triggers end of lag phase in populations of Pseudomonas fluorescens. MICROLIFE 2022; 3:uqac022. [PMID: 37223352 PMCID: PMC10117806 DOI: 10.1093/femsml/uqac022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/25/2022] [Indexed: 05/25/2023]
Abstract
The relationship between the number of cells colonizing a new environment and time for resumption of growth is a subject of long-standing interest. In microbiology this is known as the "inoculum effect." Its mechanistic basis is unclear with possible explanations ranging from the independent actions of individual cells, to collective actions of populations of cells. Here, we use a millifluidic droplet device in which the growth dynamics of hundreds of populations founded by controlled numbers of Pseudomonas fluorescens cells, ranging from a single cell, to one thousand cells, were followed in real time. Our data show that lag phase decreases with inoculum size. The decrease of average lag time and its variance across droplets, as well as lag time distribution shapes, follow predictions of extreme value theory, where the inoculum lag time is determined by the minimum value sampled from the single-cell distribution. Our experimental results show that exit from lag phase depends on strong interactions among cells, consistent with a "leader cell" triggering end of lag phase for the entire population.
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Affiliation(s)
- Maxime Ardré
- Laboratoire Biophysique et Évolution, CBI, ESPCI Paris, Université PSL, CNRS, 75005 Paris, France
| | - Guilhem Doulcier
- Laboratoire Biophysique et Évolution, CBI, ESPCI Paris, Université PSL, CNRS, 75005 Paris, France
| | - Naama Brenner
- Network Biology Research Laboratories, and Department of Chemical Engineering, Technion–Israel Institute of Technology, Haifa, Israel
| | - Paul B Rainey
- Laboratoire Biophysique et Évolution, CBI, ESPCI Paris, Université PSL, CNRS, 75005 Paris, France
- Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
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9
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De Flaviis R, Sacchetti G. Reparameterization of the Weibull model for practical uses in food science. J Food Sci 2022; 87:2096-2111. [PMID: 35355270 DOI: 10.1111/1750-3841.16124] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 01/13/2022] [Accepted: 02/27/2022] [Indexed: 11/27/2022]
Abstract
The reparameterization of the Weibull cumulative distribution function and its survival function was performed to obtain meaningful parameters in food and biological sciences such as the lag phase (λ), the maximum rate ( μ max ${\mu _{{\rm{max}}}}$ ), and the maximum increase/decrease of the function (A). The application of the Lambert function was crucial in order to achieve an explicit mathematical solution. Since the reparameterized model is applicable only when the shape parameter (α) is greater than one, the Weibull model was modified with the introduction of a new parameter ( μ β ${\mu _\beta }$ ) that represents the model rate at time β (scale parameter). All models were applied to literature data on food technology and microbiology topics: Microbial growth, thermal microbial inactivation, thermal degradation kinetics, and particle size distributions. The Weibull model and the reparameterized versions showed identical fitting performance in terms of coefficient of determination, residual mean standard error, values of residuals, and estimated values of the parameters. Some faults in the datasets used in this study permitted to re-mark the criticality of a good experimental plan when data modeling is approached. The parameter μ β ${\mu _\beta }$ resulted in an interesting new rate parameter that is not correlated with the scale parameter ( | r ¯ | $| {\bar{r}} |$ = 0.64 ± 0.37) and highly correlated with the shape parameter ( | r ¯ | $| {\bar{r}} |$ = 0.90 ± 0.11). Also, the reparameterization of the Weibull probability density function was performed by using both the standard and new parameters and applied to experimental data and gave useful information from the distribution curve, such as the value of the mode ( μ max ${\mu _{{\rm{max}}}}$ ) and a measure of the curve skewness (λ).
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Affiliation(s)
- Riccardo De Flaviis
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Giampiero Sacchetti
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
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10
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Koyama K, Hiura S, Abe H, Koseki S. Application of growth rate from kinetic model to calculate stochastic growth of a bacteria population at low contamination level. J Theor Biol 2021; 525:110758. [PMID: 33984354 DOI: 10.1016/j.jtbi.2021.110758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 04/27/2021] [Accepted: 05/01/2021] [Indexed: 11/25/2022]
Abstract
Traditional predictive microbiology is not suited for cell growth predictions for low-level contamination, where individual cell heterogeneity becomes apparent. Accordingly, we simulated a stochastic birth process of bacteria population using kinetic parameters. We predicted the variation in behavior of Salmonella enterica serovar Typhimurium cells at low inoculum density. The modeled cells were grown in tryptic soy broth at 25 °C. Kinetic growth parameters were first determined empirically for an initial cell number of 104 cells. Monte Carlo simulation based on the growth kinetics and Poisson distribution for different initial cell numbers predicted the results of 50 replicate growth experiments with the initial cell number of 1, 10, and 64 cells. Indeed, measured behavior of 85% cells fell within the 95% prediction area of the simulation. The calculations link the kinetic and stochastic birth process with Poisson distribution. The developed model can be used to calculate the probability distribution of population size for exposure assessment and for the evaluation of a probability that a pathogen would exceed critical contamination level during food storage.
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Affiliation(s)
- Kento Koyama
- Graduate School of Agricultural Science, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
| | - Satoko Hiura
- Graduate School of Agricultural Science, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
| | - Hiroki Abe
- Graduate School of Agricultural Science, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
| | - Shige Koseki
- Graduate School of Agricultural Science, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
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11
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Enrico Bena C, Del Giudice M, Grob A, Gueudré T, Miotto M, Gialama D, Osella M, Turco E, Ceroni F, De Martino A, Bosia C. Initial cell density encodes proliferative potential in cancer cell populations. Sci Rep 2021; 11:6101. [PMID: 33731745 PMCID: PMC7969775 DOI: 10.1038/s41598-021-85406-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/26/2021] [Indexed: 01/18/2023] Open
Abstract
Individual cells exhibit specific proliferative responses to changes in microenvironmental conditions. Whether such potential is constrained by the cell density throughout the growth process is however unclear. Here, we identify a theoretical framework that captures how the information encoded in the initial density of cancer cell populations impacts their growth profile. By following the growth of hundreds of populations of cancer cells, we found that the time they need to adapt to the environment decreases as the initial cell density increases. Moreover, the population growth rate shows a maximum at intermediate initial densities. With the support of a mathematical model, we show that the observed interdependence of adaptation time and growth rate is significantly at odds both with standard logistic growth models and with the Monod-like function that governs the dependence of the growth rate on nutrient levels. Our results (i) uncover and quantify a previously unnoticed heterogeneity in the growth dynamics of cancer cell populations; (ii) unveil how population growth may be affected by single-cell adaptation times; (iii) contribute to our understanding of the clinically-observed dependence of the primary and metastatic tumor take rates on the initial density of implanted cancer cells.
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Affiliation(s)
- Chiara Enrico Bena
- CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP), Sorbonne Université, 75005, Paris, France.,IIGM - Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy
| | - Marco Del Giudice
- IIGM - Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy.,Candiolo Cancer Institute, FPO - IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy
| | - Alice Grob
- Department of Life Sciences, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, London, UK
| | - Thomas Gueudré
- IIGM - Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy
| | - Mattia Miotto
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Dimitra Gialama
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Matteo Osella
- Physics Department and INFN, University of Turin, Via P. Giuria 1, 10125, Turin, Italy
| | - Emilia Turco
- Molecular Biotechnology Center, University of Turin, Via Nizza 52, 10126, Turin, Italy
| | - Francesca Ceroni
- Department of Chemical Engineering, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, London, UK
| | - Andrea De Martino
- IIGM - Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy.,Soft and Living Matter Lab, CNR-NANOTEC, Rome, Italy
| | - Carla Bosia
- IIGM - Italian Institute for Genomic Medicine, c/o IRCCS, Str. Prov.le 142, km 3.95, 10060, Candiolo, Italy. .,Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
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12
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Kakagianni M, Chatzitzika C, Koutsoumanis KP, Valdramidis VP. The impact of high power ultrasound for controlling spoilage by Alicyclobacillus acidoterrestris: A population and a single spore assessment. INNOV FOOD SCI EMERG 2020. [DOI: 10.1016/j.ifset.2020.102405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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13
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Zavatti V, Budman H, Legge RL, Tamer M. Investigation of the effects of oxidative stress-inducing factors on culturing and productivity of Bordetella pertussis. Biotechnol Prog 2019; 36:e2899. [PMID: 31483095 DOI: 10.1002/btpr.2899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/27/2019] [Accepted: 08/19/2019] [Indexed: 11/08/2022]
Abstract
The stress response of Bordetella pertussis during fermentation was assessed by means of fluorescence-based techniques. During the manufacturing of vaccines, B. pertussis is subjected to stress during adaptation to a new environment and operating conditions in the bioreactor, which can have harmful consequences on growth and protein yield. In this study, stress was imposed by varying the percentage of dissolved oxygen (DO) and inoculum size, and by adding rotenone and hydrogen peroxide. In this study, fluorescence spectroscopy is used as a tool for measuring oxidative stress. High levels of DO during fed-batch operation had no detrimental effect on growth, but the specific productivity of pertactin (PRN) decreased. Cultures that were started with an inoculum size that was 10 times smaller than the control resulted in significantly less PRN as compared to controls where reduction was more significant in flasks as compared to bioreactors. A comparison of filtered to heat-sterilized media revealed that filtered media offered a protective effect against H2 O2 . Heat sterilization of the media might result in the destruction of components that offer protection against oxidative stress. Nonetheless, filter sterilization on its own would be insufficient for large-scale manufacturing. It should be emphasized that the effects of these stressors while investigating for other microorganisms have not been studied for B. pertussis.
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Affiliation(s)
- Vanessa Zavatti
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Hector Budman
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Raymond L Legge
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Melih Tamer
- Manufacturing Technology, Sanofi Pasteur, Toronto, Ontario, Canada
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14
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Bacillus cereus cshA Is Expressed during the Lag Phase of Growth and Serves as a Potential Marker of Early Adaptation to Low Temperature and pH. Appl Environ Microbiol 2019; 85:AEM.00486-19. [PMID: 31076436 PMCID: PMC6606889 DOI: 10.1128/aem.00486-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/01/2019] [Indexed: 12/14/2022] Open
Abstract
The spore-forming bacterium B. cereus is a major cause of foodborne outbreaks in Europe. Some B. cereus strains can grow at low temperatures and low pH in many processed foods. Modeling of the bacterial lag time is hampered by a lack of knowledge of the timing of events occurring during this phase. In this context, the identification of lag phase markers, not currently available, could be a real advance for the better prediction of lag time duration. Currently, no molecular markers of this phase are available. By determining that cshA was always expressed early during the lag phase, we provide a molecular marker of the early adaptation process of B. cereus cells when exposed to low temperature and pH. Bacterial adaptation is characterized by a lag phase during which cells do not multiply or modify their physiology to cope with the constraints of their environment. Our aim was to determine a sequence of events during the lag phase of growth at low temperature and pH for three Bacillus cereus strains. The onsets of expression of two genes, one of which is essential for stress adaptation (cshA, coding for a RNA helicase) and one of which is involved in the transition between lag phase and exponential phase (abrB, coding for a transition regulator), were determined using fluorescent transcriptional reporter systems. Regardless of the stressing conditions and the tested strains, the cshA promoter was active very early, while the biomass increased and always did so before the first cell division. At 12°C and pH 7.0, the onset of cshA promoter activity occurred at between 3 h and 7 h, while the bacterial counts started to increase at between 12 h and 13 h. At pH 5.0 and at 20°C or 30°C, the onset of cshA promoter activity occurred before 1 h and earlier than at pH 7.0. In contrast, the onset of abrB promoter activity depended on the strain and the stressing conditions. In the ATCC 14579 strain, the onset of abrB promoter activity always started at between 30 min and 3 h, before biomass increased and cell division occurred. For the other strains, it took place along with the first cell division at 12°C but did so much later during growth under the other tested conditions. IMPORTANCE The spore-forming bacterium B. cereus is a major cause of foodborne outbreaks in Europe. Some B. cereus strains can grow at low temperatures and low pH in many processed foods. Modeling of the bacterial lag time is hampered by a lack of knowledge of the timing of events occurring during this phase. In this context, the identification of lag phase markers, not currently available, could be a real advance for the better prediction of lag time duration. Currently, no molecular markers of this phase are available. By determining that cshA was always expressed early during the lag phase, we provide a molecular marker of the early adaptation process of B. cereus cells when exposed to low temperature and pH.
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15
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Quinto E, Marín J, Caro I, Mateo J, Redondo-del-Río M, de-Mateo-Silleras B, Schaffner D. Bootstrap parametric GB2 and bootstrap nonparametric distributions for studying shiga toxin-producing Escherichia coli strains growth rate variability. Food Res Int 2019; 120:829-838. [DOI: 10.1016/j.foodres.2018.11.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/06/2018] [Accepted: 11/21/2018] [Indexed: 01/12/2023]
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16
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Lag Phase Is a Dynamic, Organized, Adaptive, and Evolvable Period That Prepares Bacteria for Cell Division. J Bacteriol 2019; 201:JB.00697-18. [PMID: 30642990 DOI: 10.1128/jb.00697-18] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Lag is a temporary period of nonreplication seen in bacteria that are introduced to new media. Despite latency being described by Müller in 1895, only recently have we gained insights into the cellular processes characterizing lag phase. This review covers literature to date on the transcriptomic, proteomic, metabolomic, physiological, biochemical, and evolutionary features of prokaryotic lag. Though lag is commonly described as a preparative phase that allows bacteria to harvest nutrients and adapt to new environments, the implications of recent studies indicate that a refinement of this view is well deserved. As shown, lag is a dynamic, organized, adaptive, and evolvable process that protects bacteria from threats, promotes reproductive fitness, and is broadly relevant to the study of bacterial evolution, host-pathogen interactions, antibiotic tolerance, environmental biology, molecular microbiology, and food safety.
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17
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Borujeni MS, Ghaderi-Zefrehei M, Ghanegolmohammadi F, Ansari-Mahyari S. A Novel LSSVM Based Algorithm to Increase Accuracy of Bacterial Growth Modeling. IRANIAN JOURNAL OF BIOTECHNOLOGY 2018; 16:e1542. [PMID: 30805384 PMCID: PMC6371636 DOI: 10.21859/ijb.1542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND The recent progress and achievements in the advanced, accurate, and rigorously evaluated algorithms has revolutionized different aspects of the predictive microbiology including bacterial growth. OBJECTIVES In this study, attempts were made to develop a more accurate hybrid algorithm for predicting the bacterial growth curve which can also be applicable in predictive microbiology studies. MATERIALS AND METHODS Sigmoid functions, including Logistic and Gompertz, as well as least square support vector machine (LSSVM) based algorithms were employed to model the bacterial growth of the two important strains comprising Listeria monocytogenes and Escherichia coli. Even though cross-validation is generally used for tuning the parameters in LSSVM, in this study, parameters tuning (i.e.,'c' and 'σ') of the LSSVM were optimized using non-dominated sorting genetic algorithm-II (NSGA-II), named as NSGA-II-LSSVM. Then, the results of each approach were compared with the mean absolute error (MAE) as well as the mean absolute percentage error (MAPE). RESULTS Applying LSSVM, it was resulted in a precise bacterial growth modeling compared to the sigmoid functions. Moreover, our results have indicated that NSGA-II-LSSVM was more accurate in terms of prediction than LSSVM method. CONCLUSION Application of the NSGA-II-LSSVM hybrid algorithm to predict precise values of 'c' and 'σ' parameters in the bacterial growth modeling resulted in a better growth prediction. In fact, the power of NSGA-II for estimating optimal coefficients led to a better disclosure of the predictive potential of the LSSVM.
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Affiliation(s)
- Masoud Salehi Borujeni
- Electronics Department, Electrical and Computer Engineering Faculty, Semnan University, Semnan, Iran
| | | | - Farzan Ghanegolmohammadi
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan
| | - Saeid Ansari-Mahyari
- Department of Animal Science, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
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18
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Ochiai Y, Yamada F, Yoshikawa Y, Mochizuki M, Takano T, Hondo R, Ueda F. Sequential transition of the injury phenotype, temperature-dependent survival and transcriptional response in Listeria monocytogenes following lethal H 2 O 2 exposure. Int J Food Microbiol 2017; 259:52-58. [DOI: 10.1016/j.ijfoodmicro.2017.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 07/29/2017] [Accepted: 08/01/2017] [Indexed: 11/29/2022]
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19
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Kasanke CP, Leigh MB. Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate. PLoS One 2017; 12:e0181462. [PMID: 28727811 PMCID: PMC5519087 DOI: 10.1371/journal.pone.0181462] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/18/2017] [Indexed: 11/24/2022] Open
Abstract
Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the environment, especially in cold regions. We conducted aerobic and anaerobic microcosm studies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska. We also investigated the impacts of nutrient limitations and hydrocarbon co-contamination on sulfolane degradation. We found that sulfolane underwent biodegradation aerobically but not anaerobically under nitrate, sulfate, or iron-reducing conditions. No abiotic degradation activity was detectable under either oxic or anoxic conditions. Nutrient addition stimulated sulfolane biodegradation in sediment slurries at high sulfolane concentrations (100 mg L-1), but not at low sulfolane concentrations (500 μg L-1), and nutrient amendments were necessary to stimulate sulfolane biodegradation in incubations containing groundwater only. Hydrocarbon co-contamination retarded aerobic sulfolane biodegradation rates by ~30%. Our study is the first to investigate the sulfolane biodegradation potential of subarctic aquifer substrate and identifies several important factors limiting biodegradation rates. We concluded that oxygen is an important factor limiting natural attenuation of this sulfolane plume, and that nutrient amendments are unlikely to accelerate biodegradation within in the plume, although they may biostimulate degradation in ex situ groundwater treatment applications. Future work should be directed at elucidating the identity of indigenous sulfolane-degrading microorganisms and determining their distribution and potential activity in the environment.
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Affiliation(s)
- Christopher P. Kasanke
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- * E-mail:
| | - Mary Beth Leigh
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
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20
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Estimation of growth parameters of Listeria monocytogenes after sublethal heat and slightly acidic electrolyzed water (SAEW) treatment. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.06.018] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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de J C Munanga B, Loiseau G, Grabulos J, Mestres C. Modeling Lactic Fermentation of Gowé Using Lactobacillus Starter Culture. Microorganisms 2016; 4:E44. [PMID: 27916901 PMCID: PMC5192527 DOI: 10.3390/microorganisms4040044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 11/16/2022] Open
Abstract
A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso's primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μmax values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum, respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis, with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter.
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Affiliation(s)
| | - Gérard Loiseau
- Montpellier SupAgro, UMR Qualisud, Montpellier 34398, France.
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22
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Survival of sublethally injured Listeria in model soup after nonisothermal heat and high-pressure treatments. Eur Food Res Technol 2016. [DOI: 10.1007/s00217-016-2821-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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23
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Chen Y, Pouillot R, S Burall L, Strain EA, Van Doren JM, De Jesus AJ, Laasri A, Wang H, Ali L, Tatavarthy A, Zhang G, Hu L, Day J, Sheth I, Kang J, Sahu S, Srinivasan D, Brown EW, Parish M, Zink DL, Datta AR, Hammack TS, Macarisin D. Comparative evaluation of direct plating and most probable number for enumeration of low levels of Listeria monocytogenes in naturally contaminated ice cream products. Int J Food Microbiol 2016; 241:15-22. [PMID: 27741432 DOI: 10.1016/j.ijfoodmicro.2016.09.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/11/2016] [Accepted: 09/24/2016] [Indexed: 11/25/2022]
Abstract
A precise and accurate method for enumeration of low level of Listeria monocytogenes in foods is critical to a variety of studies. In this study, paired comparison of most probable number (MPN) and direct plating enumeration of L. monocytogenes was conducted on a total of 1730 outbreak-associated ice cream samples that were naturally contaminated with low level of L. monocytogenes. MPN was performed on all 1730 samples. Direct plating was performed on all samples using the RAPID'L.mono (RLM) agar (1600 samples) and agar Listeria Ottaviani and Agosti (ALOA; 130 samples). Probabilistic analysis with Bayesian inference model was used to compare paired direct plating and MPN estimates of L. monocytogenes in ice cream samples because assumptions implicit in ordinary least squares (OLS) linear regression analyses were not met for such a comparison. The probabilistic analysis revealed good agreement between the MPN and direct plating estimates, and this agreement showed that the MPN schemes and direct plating schemes using ALOA or RLM evaluated in the present study were suitable for enumerating low levels of L. monocytogenes in these ice cream samples. The statistical analysis further revealed that OLS linear regression analyses of direct plating and MPN data did introduce bias that incorrectly characterized systematic differences between estimates from the two methods.
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Affiliation(s)
- Yi Chen
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA.
| | - Régis Pouillot
- Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Laurel S Burall
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD 20708, USA
| | - Errol A Strain
- Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Jane M Van Doren
- Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Antonio J De Jesus
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Anna Laasri
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Hua Wang
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Laila Ali
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Aparna Tatavarthy
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Guodong Zhang
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Lijun Hu
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - James Day
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Ishani Sheth
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Jihun Kang
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD 20708, USA
| | - Surasri Sahu
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD 20708, USA
| | - Devayani Srinivasan
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD 20708, USA
| | - Eric W Brown
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Mickey Parish
- Office of the Center Director, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Donald L Zink
- Office of the Center Director, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Atin R Datta
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD 20708, USA
| | - Thomas S Hammack
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Dumitru Macarisin
- Office of Regulatory Science, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
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24
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Bernini V, Dalzini E, Lazzi C, Bottari B, Gatti M, Neviani E. Cutting procedures might be responsible for Listeria monocytogenes contamination of foods: The case of Gorgonzola cheese. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Comparison of Primary Models to Predict Microbial Growth by the Plate Count and Absorbance Methods. BIOMED RESEARCH INTERNATIONAL 2015; 2015:365025. [PMID: 26539483 PMCID: PMC4619785 DOI: 10.1155/2015/365025] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/15/2015] [Indexed: 12/02/2022]
Abstract
The selection of a primary model to describe microbial growth in predictive food microbiology often appears to be subjective. The objective of this research was to check the performance of different mathematical models in predicting growth parameters, both by absorbance and plate count methods. For this purpose, growth curves of three different microorganisms (Bacillus cereus, Listeria monocytogenes, and Escherichia coli) grown under the same conditions, but with different initial concentrations each, were analysed. When measuring the microbial growth of each microorganism by optical density, almost all models provided quite high goodness of fit (r2 > 0.93) for all growth curves. The growth rate remained approximately constant for all growth curves of each microorganism, when considering one growth model, but differences were found among models. Three-phase linear model provided the lowest variation for growth rate values for all three microorganisms. Baranyi model gave a variation marginally higher, despite a much better overall fitting.
When measuring the microbial growth by plate count, similar results were obtained. These results provide insight into predictive microbiology and will help food microbiologists and researchers to choose the proper primary growth predictive model.
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26
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Combined effect of carvacrol and citral on the growth of Listeria monocytogenes and Listeria innocua and on the occurrence of damaged cells. Food Control 2015. [DOI: 10.1016/j.foodcont.2015.01.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Comparative study of the effects of citral on the growth and injury of Listeria innocua and Listeria monocytogenes cells. PLoS One 2015; 10:e0114026. [PMID: 25643164 PMCID: PMC4313941 DOI: 10.1371/journal.pone.0114026] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 11/04/2014] [Indexed: 11/19/2022] Open
Abstract
This study investigates the effect of citral on growth and on the occurrence of sublethal damage in Listeria innocua Serovar 6a (CECT 910) and Listeria monocytogenes Serovar 4b (CECT 4032) cells that were exposed to citral as a natural antimicrobial agent. Two initial inoculum concentrations were considered in this investigation: 102 and 106 cfu/mL. Citral exhibited antilisterial activity against L. innocua and L. monocytogenes, and the observed effects were dependent on the concentration of citral present in the culture medium (0, 0.150 and 0.250 μL/mL) (p ≤ 0.05). L. innocua had a shorter lag phase than L. monocytogenes, and the two species had nearly identical maximum specific growth rates. These results indicate that L. innocua could be used as surrogate for L. monocytogenes when testing the effects of this antimicrobial. Significant differences in the lag phase and growth rate were observed between the small and large inoculum concentration (p ≤ 0.05). Citral-treated L. innocua and L. monocytogenes that were recovered on selective medium (i.e., TSA-YE-SC) had a shorter lag phase and a higher maximum specific growth rate than cells that were recovered on non-selective medium (i.e., TSA-YE) (p ≤ 0.05). This result suggests that damage occurs at sublethal concentrations of citral.
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28
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Baka M, Noriega E, Stamati I, Logist F, Van Impe JF. Critical Assessment of the Time-to-Detection Method for Accurate Estimation of Microbial Growth Parameters. J Food Saf 2014. [DOI: 10.1111/jfs.12170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Baka
- BioTeC - Chemical and Biochemical Process Technology and Control; Department of Chemical Engineering; KU Leuven; Leuven Belgium
- Optimization in Engineering Center (OPTEC); Center of Excellence; KU Leuven; Leuven Belgium
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods; Belgium
| | - Estefanía Noriega
- BioTeC - Chemical and Biochemical Process Technology and Control; Department of Chemical Engineering; KU Leuven; Leuven Belgium
- Optimization in Engineering Center (OPTEC); Center of Excellence; KU Leuven; Leuven Belgium
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods; Belgium
| | - Ioanna Stamati
- BioTeC - Chemical and Biochemical Process Technology and Control; Department of Chemical Engineering; KU Leuven; Leuven Belgium
- Optimization in Engineering Center (OPTEC); Center of Excellence; KU Leuven; Leuven Belgium
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods; Belgium
| | - Filip Logist
- BioTeC - Chemical and Biochemical Process Technology and Control; Department of Chemical Engineering; KU Leuven; Leuven Belgium
- Optimization in Engineering Center (OPTEC); Center of Excellence; KU Leuven; Leuven Belgium
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods; Belgium
| | - Jan F.M. Van Impe
- BioTeC - Chemical and Biochemical Process Technology and Control; Department of Chemical Engineering; KU Leuven; Leuven Belgium
- Optimization in Engineering Center (OPTEC); Center of Excellence; KU Leuven; Leuven Belgium
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods; Belgium
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Analyzing the revolution of anaerobic ammonium oxidation (anammox) performance and sludge characteristics under zinc inhibition. Appl Microbiol Biotechnol 2014; 99:3221-32. [DOI: 10.1007/s00253-014-6205-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
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Mytilinaios I, Bernigaud I, Belot V, Lambert RJW. Microbial growth parameters obtained from the analysis of time to detection data using a novel rearrangement of the Baranyi-Roberts model. J Appl Microbiol 2014; 118:161-74. [PMID: 25393511 DOI: 10.1111/jam.12695] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/03/2014] [Accepted: 11/03/2014] [Indexed: 11/29/2022]
Abstract
AIMS To explore the predictions of a novel rearrangement of the Baranyi-Roberts model (BRM) with time to detection data obtained from optical density data of microbial growth. METHODS AND RESULTS Growth of Escherichia coli and Salmonella Typhimurium under mild conditions of temperature (25-37°C), salt (0·086, 0·51 and 1·03 mol l(-1)) and pH (6·85-4·5) was examined using optical density. Time to detection (TTD) data were fitted to a model based on a rearrangement of the BRM. Observations showed compatibility with standard viable count studies and produced highly accurate specific growth rates and lag phase durations. At high salt and low pH, however, there was a substantial dependency on the initial inoculum for the observation of visible growth. At 30 and 37°C, with 1·03 mol l(-1) salt, and at pH <5·75, no visible growth was recorded for E. coli at initial inoculum levels below 10(7) CFU ml(-1). CONCLUSIONS The rearranged BRM can be used directly with TTD data obtained from optical density measurements. SIGNIFICANCE AND IMPACT OF THE STUDY A distinct advantage of the rearranged model is that it allows for a very simple interpretation of easily obtainable data using standard nonlinear regression. The rearranged model gives to TTD data the same modelling capability that the BRM gives to plate count data.
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Affiliation(s)
- I Mytilinaios
- Applied Microbiology, School of Applied Sciences, Cranfield University, Cranfield, UK
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Rostami F, Razavi SH, Sepahi AA, Gharibzahedi SMT. Canthaxanthin biosynthesis by Dietzia natronolimnaea HS-1: effects of inoculation and aeration rate. Braz J Microbiol 2014; 45:447-56. [PMID: 25242927 PMCID: PMC4166268 DOI: 10.1590/s1517-83822014005000046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 09/09/2013] [Indexed: 11/21/2022] Open
Abstract
The interest in production of natural colorants by microbial fermentation has been currently increased. The effects of D-glucose concentration (3.18-36.82 g/L), inoculum size (12.5 × 10(9)-49.5 × 10(9) cfu cells/mL) and air-flow rate (1.95-12.05 L/L min) on the biomass, total carotenoid and canthaxanthin (CTX) accumulation of Dietzia natronolimnaea HS-1 in a batch bioreactor was scrutinized using a response surface methodology-central composite rotatable design (RSM-CCRD). Second-order polynomial models with high R (2) values ranging from 0.978 to 0.990 were developed for the studied responses using multiple linear regression analysis. The models showed the maximum cumulative amounts of biomass (7.85 g/L), total carotenoid (5.48 mg/L) and CTX (4.99 mg/L) could be achieved at 23.38 g/L of D-glucose, 31.2 × 10(9) cfu cells/mL of inoculation intensity and air-flow rate of 7.85 L/L min. The predicted values for optimum conditions were in good agreement with experimental data.
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Affiliation(s)
- Forouzan Rostami
- Bioprocess Engineering Laboratory Department of Food Science & Engineering Faculty of Agricultural Engineering and Technology University of Tehran Karaj Iran Bioprocess Engineering Laboratory, Department of Food Science & Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran. ; Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks University of Tehran Karaj Iran Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks, University of Tehran, Karaj, Iran
| | - Seyed Hadi Razavi
- Bioprocess Engineering Laboratory Department of Food Science & Engineering Faculty of Agricultural Engineering and Technology University of Tehran Karaj Iran Bioprocess Engineering Laboratory, Department of Food Science & Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran. ; Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks University of Tehran Karaj Iran Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks, University of Tehran, Karaj, Iran
| | - Abbas Akhavan Sepahi
- Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks University of Tehran Karaj Iran Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks, University of Tehran, Karaj, Iran
| | - Seyed Mohammad Taghi Gharibzahedi
- Bioprocess Engineering Laboratory Department of Food Science & Engineering Faculty of Agricultural Engineering and Technology University of Tehran Karaj Iran Bioprocess Engineering Laboratory, Department of Food Science & Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran. ; Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks University of Tehran Karaj Iran Iranian Center of Excellence for Application of Modern Technologies for Producing Functional Foods and Drinks, University of Tehran, Karaj, Iran
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Wang JJ, Sun WS, Jin MT, Liu HQ, Zhang W, Sun XH, Pan YJ, Zhao Y. Fate of Vibrio parahaemolyticus on shrimp after acidic electrolyzed water treatment. Int J Food Microbiol 2014; 179:50-6. [DOI: 10.1016/j.ijfoodmicro.2014.03.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/09/2014] [Accepted: 03/13/2014] [Indexed: 12/14/2022]
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Silva-Angulo A, Zanini S, Rodrigo D, Rosenthal A, Martinez A. Growth kinetics of Listeria innocua and Listeria monocytogenes under exposure to carvacrol and the occurrence of sublethal damage. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.09.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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34
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Bernini V, Bottari B, Dalzini E, Sgarbi E, Lazzi C, Neviani E, Gatti M. The presence, genetic diversity and behaviour of Listeria monocytogenes in blue-veined cheese rinds during the shelf life. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Aguirre JS, Monis A, García de Fernando GD. Improvement in the lag phase estimation of individual cells that have survived mild heat treatment. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juan S. Aguirre
- Grupo de Tecnología de los Alimentos de Origen Animal; Depto. Nutrición, Bromatología y Tecnología de los Alimentos; Facultad de Veterinaria; Universidad Complutense; Ciudad Universitaria; Madrid 28040 Spain
| | - Almira Monis
- Grupo de Tecnología de los Alimentos de Origen Animal; Depto. Nutrición, Bromatología y Tecnología de los Alimentos; Facultad de Veterinaria; Universidad Complutense; Ciudad Universitaria; Madrid 28040 Spain
| | - Gonzalo D. García de Fernando
- Grupo de Tecnología de los Alimentos de Origen Animal; Depto. Nutrición, Bromatología y Tecnología de los Alimentos; Facultad de Veterinaria; Universidad Complutense; Ciudad Universitaria; Madrid 28040 Spain
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Aguirre JS, González A, Özçelik N, Rodríguez MR, García de Fernando GD. Modeling the Listeria innocua micropopulation lag phase and its variability. Int J Food Microbiol 2013; 164:60-9. [DOI: 10.1016/j.ijfoodmicro.2013.03.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/11/2013] [Accepted: 03/10/2013] [Indexed: 10/27/2022]
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37
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Huang S, Chen XD. Significant effect of Ca2+on improving the heat resistance of lactic acid bacteria. FEMS Microbiol Lett 2013; 344:31-8. [DOI: 10.1111/1574-6968.12151] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 03/22/2013] [Accepted: 04/02/2013] [Indexed: 11/26/2022] Open
Affiliation(s)
- Song Huang
- Department of Chemical and Biochemical Engineering; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen; China
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38
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Lee S, Cho K, Lim J, Kim W, Hwang S. Acclimation and activity of ammonia-oxidizing bacteria with respect to variations in zinc concentration, temperature, and microbial population. BIORESOURCE TECHNOLOGY 2011; 102:4196-4203. [PMID: 21196116 DOI: 10.1016/j.biortech.2010.12.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/06/2010] [Accepted: 12/07/2010] [Indexed: 05/30/2023]
Abstract
Activity of ammonia-oxidizing bacteria (AOB) to simultaneous variation in Zn(2+) concentration (0.01-3.5mg/L), temperature (23-33°C), and AOB concentration (3-30 × 10(6)gene copies/mL) in a steel industry wastewater treatment plant was evaluated. Two equations were developed to describe the lag period (i.e., AOB acclimation) and ammonia oxidation rate (i.e., growth of the AOB) depending on the variables. AOB concentration and temperature both had significant effects on lag period and the ammonia oxidation rate. Zn(2+) concentration only had a significant effect on ammonia oxidation rate at 5% α-level. There was a significant interaction between AOB concentration and temperature for both lag period and ammonia oxidation rate. The effects of the variables were not significant when AOB concentration was higher than 2.0 × 10(7)copies/mL. There was no visible shift or changes in AOB communities based on DGGE analysis with amoA gene primers.
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Affiliation(s)
- Seungyong Lee
- School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, South Korea
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Valero A, Rodríguez M, Carrasco E, Pérez-Rodríguez F, García-Gimeno R, Zurera G. Studying the growth boundary and subsequent time to growth of pathogenic Escherichia coli serotypes by turbidity measurements. Food Microbiol 2010; 27:819-28. [DOI: 10.1016/j.fm.2010.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 10/19/2022]
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40
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Rivoal K, Quéguiner S, Boscher E, Bougeard S, Ermel G, Salvat G, Federighi M, Jugiau F, Protais J. Detection of Listeria monocytogenes in raw and pasteurized liquid whole eggs and characterization by PFGE. Int J Food Microbiol 2010; 138:56-62. [DOI: 10.1016/j.ijfoodmicro.2010.01.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 01/04/2010] [Accepted: 01/10/2010] [Indexed: 10/20/2022]
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41
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Seo SM, Cho IH, Kim JH, Jeon JW, Oh EG, Yu HS, Shin SB, Lee HJ, Paek SH. An ELISA-on-a-Chip Biosensor System for Early Screening of Listeria monocytogenes in Contaminated Food Products. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.12.2993] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Pal A, Labuza TP, Diez-Gonzalez F. Safety-based shelf life model for frankfurters based on time to detect Listeria monocytogenes with initial inoculum below detection limit. J Food Prot 2009; 72:1878-84. [PMID: 19777889 DOI: 10.4315/0362-028x-72.9.1878] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The growth of Listeria monocytogenes inoculated on frankfurters at four inoculum levels (0.1, 0.04, 0.01, and 0.007 CFU/g) was examined at 4, 8, and 12 degrees C until the time L. monocytogenes populations reached a detectable limit of at least 2 CFU/g. A scaled-down assumption was made to simulate a 25-g sample from a 100-lb batch size in a factory setting by using a 0.55-g sample from a 1,000-g batch size in a laboratory. Samples of 0.55 g were enriched in PDX-LIB selective medium, and presumptive results were confirmed on modified Oxford agar. Based on the time to detect (TTD) from each inoculum level and at each temperature, a shelf life model was constructed to predict the detection or risk levels reached by L. monocytogenes on frankfurters. The TTD increased with reductions in inoculum size and storage temperature. At 4 degrees C the TTDs (+/- standard error) observed were 42.0 +/- 1.0, 43.5 +/- 0.5, 50.7 +/- 1.5, and 55.0 +/- 3.0 days when the inoculum sizes were 0.1, 0.04, 0.01, and 0.007 CFU/g, respectively. From the same corresponding inoculum sizes, the TTDs at 8 degrees C were 4.5 +/- 0.5, 6.5 +/- 0.5, 7.0 +/- 1.0, and 8.5 +/- 0.5 days. Significant differences (P < 0.05) between TTDs were observed only when the inoculum sizes differed by at least 2 log. On a shelf life plot of 1n (TTD) versus temperature, the Q10 (increase in TTD for a 10 degrees C increase in temperature) values ranged from 24.5 to 44.7 and with no significant influence from the inoculum densities. When the observed TTDs were compared with the expected detection times based on the data obtained from a study with an inoculum size of 10 to 20 CFU/g, significant deviations were noted at lower inoculum levels. These results can be valuable in designing a safety-based shelf life model for frankfurters and in performing quantitative risk assessment of listeriosis at low and practical contamination levels.
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Affiliation(s)
- Amit Pal
- Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul, Minnesota 55108, USA
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43
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Pouillot R, Goulet V, Delignette-Muller ML, Mahé A, Cornu M. Quantitative risk assessment of Listeria monocytogenes in French cold-smoked salmon: II. Risk characterization. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2009; 29:806-819. [PMID: 19220799 DOI: 10.1111/j.1539-6924.2008.01200.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A model for the assessment of exposure to Listeria monocytogenes from cold-smoked salmon consumption in France was presented in the first of this pair of articles (Pouillot et al., 2007, Risk Analysis, 27:683-700). In the present study, the exposure model output was combined with an internationally accepted hazard characterization model, adapted to the French situation, to assess the risk of invasive listeriosis from cold-smoked salmon consumption in France in a second-order Monte Carlo simulation framework. The annual number of cases of invasive listeriosis due to cold-smoked salmon consumption in France is estimated to be 307, with a very large credible interval ([10; 12,453]), reflecting data uncertainty. This uncertainty is mainly associated with the dose-response model. Despite the significant uncertainty associated with the predictions, this model provides a scientific base for risk managers and food business operators to manage the risk linked to cold-smoked salmon contaminated with L. monocytogenes. Under the modeling assumptions, risk would be efficiently reduced through a decrease in the prevalence of L. monocytogenes or better control of the last steps of the cold chain (shorter and/or colder storage during the consumer step), whereas reduction of the initial contamination levels of the contaminated products and improvement in the first steps of the cold chain do not seem to be promising strategies. An attempt to apply the recent risk-based concept of FSO (food safety objective) on this example underlines the ambiguity in practical implementation of the risk management metrics and the need for further elaboration on these concepts.
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Affiliation(s)
- Régis Pouillot
- Agence Française de Sécurité Sanitaire des Aliments (Afssa), Maisons-Alfort, France
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44
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Dupont C, Augustin JC. Influence of stress on single-cell lag time and growth probability for Listeria monocytogenes in half Fraser broth. Appl Environ Microbiol 2009; 75:3069-76. [PMID: 19304822 PMCID: PMC2681640 DOI: 10.1128/aem.02864-08] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 03/14/2009] [Indexed: 11/20/2022] Open
Abstract
The impacts of 12 common food industry stresses on the single-cell growth probability and single-cell lag time distribution of Listeria monocytogenes were determined in half Fraser broth, the primary enrichment broth of the International Organization for Standardization detection method. First, it was determined that the ability of a cell to multiply in half Fraser broth is conditioned by its history (the probability for a cell to multiply can be decreased to 0.05), meaning that, depending on the stress in question, the risk of false-negative samples can be very high. Second, it was established that when cells are injured, the single-cell lag times increase in mean and in variability and that this increase represents a true risk of not reaching the detection threshold of the method in the enrichment broth. No relationship was observed between the impact on single-cell lag times and that on growth probabilities. These results emphasize the importance of taking into account the physiological state of the cells when evaluating the performance of methods to detect pathogens in food.
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Affiliation(s)
- Claire Dupont
- Ecole Nationale Vétérinaire d'Alfort, Unité Microbiologie des Aliments-Sécurité et Qualité, 7 Avenue du Général de Gaulle, F-94704 Maisons-Alfort Cedex, France.
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45
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Bacterial growth properties at low optical densities. Antonie Van Leeuwenhoek 2009; 96:267-74. [DOI: 10.1007/s10482-009-9342-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
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46
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A study on the variability in the growth limits of individual cells and its effect on the behavior of microbial populations. Int J Food Microbiol 2008; 128:116-21. [DOI: 10.1016/j.ijfoodmicro.2008.07.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 05/09/2008] [Accepted: 07/14/2008] [Indexed: 11/21/2022]
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Abstract
After inoculation, the times to the first divisions are longer and more widely distributed for those Escherichia coli single cells that spent more time in the stationary phase prior to inoculation. The second generation times are still longer than the typical generation times in the exponential phase, and this extended the apparent lag time of the cell population. The greater the variability of the single-cell interdivision intervals, the shorter are both the lag time and the doubling time of the population.
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Becker PM, Galletti S, Roubos-van den Hil PJ, van Wikselaar PG. Validation of growth as measurand for bacterial adhesion to food and feed ingredients. J Appl Microbiol 2007; 103:2686-96. [PMID: 17850303 DOI: 10.1111/j.1365-2672.2007.03524.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS A miniaturized adhesion test was designed to study the binding capacity of food and feed ingredients for bacterial cells. METHODS AND RESULTS Bacteria were allowed to adhere to different fibrous materials supplied as well coatings in microtitration plates. The amount of bacteria retained on the materials was determined in an automated way as growth after addition of liquid medium. The test principle was based on an inverse relationship between initial cell densities and the appearance of growth: The higher adhering cell numbers are, the shorter are the detection times of growth. The growth curves obtained were fitted by nonlinear regression analysis employing a sigmoidal curve model. Growth parameters as (i) the time after incubation at which half of the maximum growth yield was reached; (ii) the time-coordinate of the point of inflection; (iii) the detection time calculated as x-axis intercept of the maximum specific growth rate in the point of inflection; and (iv) the time-coordinate of a growth detection threshold at OD = 0.05 were highly separating for the binding capacity of different food and feed ingredients for bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY With growth as measurand for adhesion, a simple, high-throughput method was developed for the screening of huge numbers of different binding matrices and bacteria.
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Affiliation(s)
- P M Becker
- Animal Sciences Group, Wageningen UR, Lelystad, The Netherlands.
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49
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Peleg M, Corradini MG, Normand MD. The logistic (Verhulst) model for sigmoid microbial growth curves revisited. Food Res Int 2007. [DOI: 10.1016/j.foodres.2007.01.012] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Métris A, George SM, Baranyi J. Use of optical density detection times to assess the effect of acetic acid on single-cell kinetics. Appl Environ Microbiol 2006; 72:6674-9. [PMID: 16950913 PMCID: PMC1610314 DOI: 10.1128/aem.00914-06] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The growth of Listeria innocua at different acetic acid concentrations (0 to 2,000 ppm) was monitored by optical density measurements in a Bioscreen (Labsystems, Vantaa, Finland). The generated populations came from low inocula that were obtained by serial dilution. A new method to estimate both the growth rate and the lag time of single cells from the detection times (time to reach an optical density of 0.11) was developed. It assumes that the single-cell lag times follow a gamma distribution and takes into account the randomness of the inoculation level. (The initial cell number per well was assumed to follow a Poisson distribution.) In this way, relatively small numbers of replicates are sufficient to obtain a robust estimation of the distribution of single-cell lag times. The results were validated with plate count experiments. It was found that logarithms of both the growth rates and of population lag times increased linearly with the acetic acid concentration. The logarithm of the scale parameter of the gamma distribution of the single-cell lag times also increased linearly with the acetic acid concentration irrespective of the phase of the inoculum.
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Affiliation(s)
- A Métris
- Institute of Food Research, NRP, Norwich NR4 7UA, United Kingdom.
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