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Heat Adaptation Improved Cell Viability of Probiotic Enterococcus faecium HL7 upon Various Environmental Stresses. Probiotics Antimicrob Proteins 2020; 11:618-626. [PMID: 29478227 DOI: 10.1007/s12602-018-9400-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The production of viable functional probiotics presupposes stability of strain features in the final product. In previous studies, Enterococcus faecium HL7 was found to have relatively higher cell viability after freeze-drying and the long-lasting resistance to heat (60 °C) as well as higher antimicrobial activities against some of fish and human pathogens among isolated strains. For heat adaptation, E. faecium HL7 cells were exposed to 52 °C for 15 min. After adaption, slight decreases of unsaturated membrane fatty acid ratios were confirmed through fatty acid analysis. Upon subsequent exposure to various stress conditions such as H2O2 (0.01%), ethanol (20%), acid (pH 3), and alkali (pH 12), the survival rate of heat-adapted HL7 was 103-105-fold higher than that of non-adapted one. These results highlight the potential of preconditioning treatments for maximizing survival of probiotic bacteria during development of probiotic functional foods. The cross-protection afforded by acid against thermal stress may indicate that certain common protective mechanisms are induced by both heat and acid stress. These results can be applied to enhancing the cell viability during live cell formulation of E. faecium HL7 to be used as a potential probiotics in aquaculture.
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Qin X, Dong R, He S, Zhou X, Zhang Z, Cui Y, Shi C, Liu Y, Shi X. Characterization of the role of ybgC in lysozyme resistance of Salmonella Enteritidis. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Kim C, Bushlaibi M, Alrefaei R, Ndegwa E, Kaseloo P, Wynn C. Influence of prior pH and thermal stresses on thermal tolerance of foodborne pathogens. Food Sci Nutr 2019; 7:2033-2042. [PMID: 31289651 PMCID: PMC6593373 DOI: 10.1002/fsn3.1034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/19/2019] [Accepted: 03/27/2019] [Indexed: 11/23/2022] Open
Abstract
Improper food processing is one of the major causes of foodborne illness. Accurate prediction of the thermal destruction rate of foodborne pathogens is therefore vital to ensure proper processing and food safety. When bacteria are subjected to pH and thermal stresses during growth, sublethal stresses can occur that may lead to differences in their subsequent tolerance to thermal treatment. As a preliminary study to test this concept, the current study evaluated the effect of prior pH and thermal stresses on thermal tolerance of Salmonella and Staphylococcus using a tryptic soy broth supplemented with yeast extract. Bacteria incubated at three pH values (6.0, 7.4, and 9.0) and four temperatures (15, 25, 35, and 45°C) for 24 hr were subjected to thermal treatments at 55, 60, and 65°C. At the end of each treatment time, bacterial suspensions were surface-plated on standard method agar for quantification of bacterial survival and further calculation of the thermal death decimal reduction time (D-value) and thermal destruction temperature (z-value). The effect of pH stress alone during the incubation on the thermal tolerance of both bacteria was generally insignificant. An increasing pattern of D-value was observed with the increment of thermal stress (incubation temperature). The bacteria incubated at 35°C required the highest z-value to reduce the 90% in D-values. Staphylococcus mostly displayed higher tolerance to thermal treatment than Salmonella. Although further research is needed to validate the current findings on food matrices, findings in this study clearly affirm that adaptation of bacteria to certain stresses may reduce the effectiveness of preservation procedures applied during later stage of food processing and storage.
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Affiliation(s)
- Chyer Kim
- Agricultural Research StationVirginia State UniversityPetersburgVirginia
| | - Mariam Bushlaibi
- Department of BiologyVirginia State UniversityPetersburgVirginia
| | - Rana Alrefaei
- Department of BiologyVirginia State UniversityPetersburgVirginia
| | - Eunice Ndegwa
- Agricultural Research StationVirginia State UniversityPetersburgVirginia
| | - Paul Kaseloo
- Department of BiologyVirginia State UniversityPetersburgVirginia
| | - Crystal Wynn
- Department of Family and Consumer SciencesVirginia State UniversityPetersburgVirginia
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Bisignano C, Ginestra G, Smeriglio A, La Camera E, Crisafi G, Franchina FA, Tranchida PQ, Alibrandi A, Trombetta D, Mondello L, Mandalari G. Study of the Lipid Profile of ATCC and Clinical Strains of Staphylococcus aureus in Relation to Their Antibiotic Resistance. Molecules 2019; 24:molecules24071276. [PMID: 30986911 PMCID: PMC6480324 DOI: 10.3390/molecules24071276] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/22/2019] [Accepted: 03/29/2019] [Indexed: 11/16/2022] Open
Abstract
A number of reports have indicated a relationship between bacterial resistance to antibiotics and their lipid composition. In the present study, we characterized the lipid profiles of American Type Culture Collection (ATCC) and clinical strains of Staphylococcus aureus and its correlation with antibiotic resistance and hydrophobicity. The following strains were used: S. aureus ATCC 6538P, S. aureus ATCC 43300 (MRSA), seven clinical strains from the pharynges, two strains from duodenal ulcers, four strains from hip prostheses, and one strain from the conjunctiva. Lipid-related differentiation was observed across the S. aureus strains: the higher abundance of anteiso-pentadecanoic acid (anteiso-C15:0) and anteiso-heptadecanoic acid (anteiso-C17:0), followed by iso-pentadecanoic acid (iso-C15:0), suggested that these were common lipids. Iso-tridecanoic acid (iso-C13:0) and anteiso-tridecanoic acid (anteiso-C13:0), iso-hexadecanoic acid (iso-C16:0) and anteiso-hexadecanoic acid (anteiso-C16:0), and all forms of octadecanoic acid (C18:0) were usually detected in low abundance. Strains isolated from pharynges showed the highest ratio of branched/straight chains. A distinction in two clusters based on the amount and type of bacterial lipids identified was obtained, which correlated to the antibiotic resistance, the strains origin, and the cell-surface hydrophobicity. We report a potential correlation between the lipid profile of S. aureus strains, site of infection, antibiotic resistance, and cell-surface hydrophobicity. These results, which still need further insights, could be a first step to identifying antibiotic resistance in response to environmental adaptation.
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Affiliation(s)
- Carlo Bisignano
- Department of Biomedical, Dental, Morphological and Functional Images Sciences, University of Messina, Via C. Valeria, 98125 Messina, Italy.
| | - Giovanna Ginestra
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Antonella Smeriglio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Erminia La Camera
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Giuseppe Crisafi
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Flavio A Franchina
- Chromaleont c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
- School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA.
- University of Liège, Molecular System Organic & Biological Analytical Chemistry, 11 Allée du Six Août, 4000 Liège, Belgium.
| | - Peter Q Tranchida
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Angela Alibrandi
- Department of Economics, Unit of Statistical and Mathematical Sciences, University of Messina, 98125 Messina, Italy.
| | - Domenico Trombetta
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Luigi Mondello
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
- Chromaleont c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
| | - Giuseppina Mandalari
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, I-98168 Messina, Italy.
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Ben Mouhoub R, El May A, Boujezza I, Sethom MM, Feki M, Landoulsi A. Viability and membrane lipid composition under a 57mT static magnetic field in Salmonella Hadar. Bioelectrochemistry 2018; 122:134-141. [PMID: 29627665 DOI: 10.1016/j.bioelechem.2018.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 10/17/2022]
Abstract
The aim of this work is to demonstrate the effects of a static magnetic field (SMF) with an induction 12 equal to 57mT on the viability and membrane lipid composition of Salmonella Hadar. Results showed an increase in the viability of exposed bacteria compared to controls after 9h of exposure. Analysis with gas chromatography of total lipids (TLs) and different fractions of phospholipids: phosphatidylglycerols (PGs), phosphatidylethanolamines (PEs), and cardiolipins (CLs), separated by thin layer chromatography revealed changes in fatty acid levels during exposure. For TLs, the unsaturated fatty acids/saturated fatty acids ratio (UFAs/SFAs) had significantly increased after 9 h of exposure. The variation of this ratio seems to be essentially due to the increase of the proportion of unsaturated fatty acids with 18 carbons, in particular C18:1. The analyses of fatty acid composition carried out on the scale of each fraction of phospholipids showed that CLs contributed significantly to the increase of the proportion of the unsaturated fatty acids between 6 and 9h of exposure thanks to their unsaturated chains with 18 carbons (especially C18:2). CLs appear to be the main phospholipid involved in the adaptation of S. Hadar membranes to the SMF.
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Affiliation(s)
- Ramla Ben Mouhoub
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia.
| | - Alya El May
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
| | - Imen Boujezza
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
| | - Mohamed Marouen Sethom
- Université de Tunis El Manar, Faculté de Médecine de Tunis, CHU La Rabta, Laboratoire de Biochimie, LR99ES11, Jebbari, 1007 Tunis, Tunisia
| | - Moncef Feki
- Université de Tunis El Manar, Faculté de Médecine de Tunis, CHU La Rabta, Laboratoire de Biochimie, LR99ES11, Jebbari, 1007 Tunis, Tunisia
| | - Ahmed Landoulsi
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
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Calvo T, Alvarez-Ordóñez A, Prieto M, Bernardo A, López M. Stress adaptation has a minor impact on the effectivity of Non-Thermal Atmospheric Plasma (NTAP) against Salmonella spp. Food Res Int 2017; 102:519-525. [DOI: 10.1016/j.foodres.2017.09.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/07/2017] [Accepted: 09/09/2017] [Indexed: 11/28/2022]
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7
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Singh P, Lee H, Silva M, Chin K, Kang I. Trisodium phosphate dip, hot water dip, and combination dip with/without brushing on broiler carcass decontamination. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Dawoud TM, Davis ML, Park SH, Kim SA, Kwon YM, Jarvis N, O’Bryan CA, Shi Z, Crandall PG, Ricke SC. The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review. Front Vet Sci 2017; 4:93. [PMID: 28660201 PMCID: PMC5469892 DOI: 10.3389/fvets.2017.00093] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection.
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Affiliation(s)
- Turki M. Dawoud
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Morgan L. Davis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Si Hong Park
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Sun Ae Kim
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Young Min Kwon
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Nathan Jarvis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Corliss A. O’Bryan
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Zhaohao Shi
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Philip G. Crandall
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Steven C. Ricke
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
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9
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Influence of static magnetic field exposure on fatty acid composition in Salmonella Hadar. Microb Pathog 2017; 108:13-20. [PMID: 28455137 DOI: 10.1016/j.micpath.2017.04.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/23/2017] [Accepted: 04/24/2017] [Indexed: 11/20/2022]
Abstract
We have been interested, in this work, to investigate the effect of the exposure to static magnetic field at 200 mT (SMF) on the fatty acid (FA) composition of Salmonella enterica subsp Enterica serovar Hadar isolate 287: effects on the proportion of saturated and unsaturated fatty acids (SFAs, UFAs), cyclopropane fatty acids (CFAs) and hydroxy fatty acids after exposure to the static magnetic field at 200 mT (SMF). Analysis with Gas Chromatography-Mass Spectrometry (GC-MS) of total lipid showed that the proportion of the most fatty acids was clearly affected. The comparison of UFAs/SFAs ratio in exposed bacteria and controls showed a diminution after 3 and 6 h of exposure. This ration reached a balance after 9 h of treatment with SMF. So we can conclude that S. Hadar tries to adapt to magnetic stress by changing the proportions of SFAs and UFAs over time to maintain an equilibrium after 9 h of exposure, thus to maintain the inner membranes fluidity. Also, a decrease in the proportion of hydroxy FAs was observed after 6 h but an increase of this proportion after 9 h of exposure. Concerning CFAs, its proportion raised after 6 h of exposure to the SMF but it decreased after 9 h of exposure. These results are strongly correlated with those of cfa (cyclopropane fatty acid synthase) gene expression which showed a decrease of its expression after 9 h of exposure.
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Pesingi PK, Kumawat M, Behera P, Dixit SK, Agarwal RK, Goswami TK, Mahawar M. Protein-L-Isoaspartyl Methyltransferase (PIMT) Is Required for Survival of Salmonella Typhimurium at 42°C and Contributes to the Virulence in Poultry. Front Microbiol 2017; 8:361. [PMID: 28326072 PMCID: PMC5339242 DOI: 10.3389/fmicb.2017.00361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/21/2017] [Indexed: 01/07/2023] Open
Abstract
Poultry birds are asymptomatic reservoir of Salmonella Typhimurium (S. Typhimurium) but act as source of human infection for this bacterium. Inside the poultry, S. Typhimurium experiences several stresses, 42°C body temperature of birds is one of them. Proteins are highly susceptible to temperature mediated damage. Conversion of protein bound aspartate (Asp) residues to iso-aspartate (iso-Asp) is one of such modifications that occur at elevated temperature. Iso-Asp formation has been linked to protein inactivation and compromised cellular survival. Protein-L-isoaspartyl methyltransferase (PIMT) can repair iso-Asp back to Asp, thus enhances the cellular survival at elevated temperature. Here, we show that the pimt gene deletion strain of S. Typhimurium (Δpimt mutant strain) is hypersensitive to 42°C in vitro. The hypersusceptibility of Δpimt strain is partially reversed by plasmid based complementation (trans-complementation) of Δpimt strain. Following oral inoculation, Δpimt strain showed defective colonization in poultry caecum, and compromised dissemination to spleen and liver. Interestingly, we have observed three and half folds induction of the PIMT protein following exposure of S. Typhimurium to 42°C. Our data suggest a novel role of pimt gene in the survival of S. Typhimurium at elevated temperature and virulence.
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Affiliation(s)
- Pavan K Pesingi
- Division of Veterinary Public Health, Indian Veterinary Research Institute Izatnagar, India
| | - Manoj Kumawat
- Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India
| | - Pranatee Behera
- Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India
| | - Sunil K Dixit
- Division of Immunology, Indian Veterinary Research Institute Izatnagar, India
| | - Rajesh K Agarwal
- Division of Bacteriology and Mycology, Indian Veterinary Research Institute Izatnagar, India
| | - Tapas K Goswami
- Division of Immunology, Indian Veterinary Research Institute Izatnagar, India
| | - Manish Mahawar
- Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India
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Influence of Low-Shear Modeled Microgravity on Heat Resistance, Membrane Fatty Acid Composition, and Heat Stress-Related Gene Expression in Escherichia coli O157:H7 ATCC 35150, ATCC 43889, ATCC 43890, and ATCC 43895. Appl Environ Microbiol 2016; 82:2893-2901. [PMID: 26944847 DOI: 10.1128/aem.00050-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/01/2016] [Indexed: 12/27/2022] Open
Abstract
UNLABELLED We previously showed that modeled microgravity conditions alter the physiological characteristics of Escherichia coli O157:H7. To examine how microgravity conditions affect bacterial heat stress responses, D values, membrane fatty acid composition, and heat stress-related gene expression (clpB, dnaK, grpE, groES, htpG, htpX, ibpB, and rpoH), E. coli O157:H7 ATCC 35150, ATCC 43889, ATCC 43890, and ATCC 43895 were cultured under two different conditions: low-shear modeled microgravity (LSMMG, an analog of spaceflight conditions) and normal gravity (NG, Earth-like conditions). When 24-h cultures were heated to 55°C, cells cultured under LSMMG conditions showed reduced survival compared with cells cultured under NG conditions at all time points (P < 0.05). D values of all tested strains were lower after LSMMG culture than after NG culture. Fourteen of 37 fatty acids examined were present in the bacterial membrane: nine saturated fatty acids (SFA) and five unsaturated fatty acids (USFA). The USFA/SFA ratio, a measure of membrane fluidity, was higher under LSMMG conditions than under NG conditions. Compared with control cells grown under NG conditions, cells cultured under LSMMG conditions showed downregulation of eight heat stress-related genes (average, -1.9- to -3.7-fold). The results of this study indicate that in a simulated space environment, heat resistance of E. coli O157:H7 decreased, and this might be due to the synergistic effects of the increases in membrane fluidity and downregulated relevant heat stress genes. IMPORTANCE Microgravity is a major factor that represents the environmental conditions in space. Since infectious diseases are difficult to deal with in a space environment, comprehensive studies on the behavior of pathogenic bacteria under microgravity conditions are warranted. This study reports the changes in heat stress resistance of E. coli O157:H7, the severe foodborne pathogen, under conditions that mimic microgravity. The results provide scientific clues for further understanding of the bacterial response under the simulated microgravity conditions. It will contribute not only to the improvement of scientific knowledge in the academic fields but also ultimately to the development of a prevention strategy for bacterial disease in the space environment.
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FabR regulates Salmonella biofilm formation via its direct target FabB. BMC Genomics 2016; 17:253. [PMID: 27004424 PMCID: PMC4804515 DOI: 10.1186/s12864-016-2387-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 01/08/2016] [Indexed: 12/02/2022] Open
Abstract
Background Biofilm formation is an important survival strategy of Salmonella in all environments. By mutant screening, we showed a knock-out mutant of fabR, encoding a repressor of unsaturated fatty acid biosynthesis (UFA), to have impaired biofilm formation. In order to unravel how this regulator impinges on Salmonella biofilm formation, we aimed at elucidating the S. Typhimurium FabR regulon. Hereto, we applied a combinatorial high-throughput approach, combining ChIP-chip with transcriptomics. Results All the previously identified E. coli FabR transcriptional target genes (fabA, fabB and yqfA) were shown to be direct S. Typhimurium FabR targets as well. As we found a fabB overexpressing strain to partly mimic the biofilm defect of the fabR mutant, the effect of FabR on biofilms can be attributed at least partly to FabB, which plays a key role in UFA biosynthesis. Additionally, ChIP-chip identified a number of novel direct FabR targets (the intergenic regions between hpaR/hpaG and ddg/ydfZ) and yet putative direct targets (i.a. genes involved in tRNA metabolism, ribosome synthesis and translation). Next to UFA biosynthesis, a number of these direct targets and other indirect targets identified by transcriptomics (e.g. ribosomal genes, ompA, ompC, ompX, osmB, osmC, sseI), could possibly contribute to the effect of FabR on biofilm formation. Conclusion Overall, our results point at the importance of FabR and UFA biosynthesis in Salmonella biofilm formation and their role as potential targets for biofilm inhibitory strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2387-x) contains supplementary material, which is available to authorized users.
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Proteomic Analyses of Chlorhexidine Tolerance Mechanisms in Delftia acidovorans Biofilms. mSphere 2016; 1:mSphere00017-15. [PMID: 27303691 PMCID: PMC4863599 DOI: 10.1128/msphere.00017-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/04/2015] [Indexed: 01/02/2023] Open
Abstract
Protein expression and fatty acid profiles of biofilm cells of chlorhexidine-tolerant Delftia acidovorans (MIC = 15 µg/ml) and its chlorhexidine-susceptible mutant (MIC = 1 µg/ml) were investigated. The chlorhexidine-susceptible mutant (MT51) was derived from the parental strain (WT15) using Tn5 transposon mutagenesis. The disrupted gene was identified as tolQ, a component of the tolQRAB gene cluster known to be involved in outer membrane stability. Proteomic responses of biofilm cells were compared by differential in-gel electrophoresis following exposure to chlorhexidine at sub-MIC (10 µg/ml) and above-MIC (30 µg/ml) concentrations. Numerous changes in protein abundance were observed in biofilm cells following chlorhexidine exposure, suggesting that molecular changes occurred during adaptation to chlorhexidine. Forty proteins showing significant differences (≥1.5-fold; P < 0.05) were identified by mass spectrometry and were associated with various functions, including amino acid and lipid biosynthesis, protein translation, energy metabolism, and stress-related functions (e.g., GroEL, aspartyl/glutamyl-tRNA amidotransferase, elongation factor Tu, Clp protease, and hydroxymyristoyl-ACP dehydratase). Several proteins involved in fatty acid synthesis were affected by chlorhexidine, in agreement with fatty acid analysis, wherein chlorhexidine-induced shifts in the fatty acid profile were observed in the chlorhexidine-tolerant cells, primarily the cyclic fatty acids. Transmission electron microscopy revealed more prominent changes in the cell envelope of chlorhexidine-susceptible MT51 cells. This study suggests that multiple mechanisms involving both the cell envelope (and likely TolQ) and panmetabolic regulation play roles in chlorhexidine tolerance in D. acidovorans. IMPORTANCE Delftia acidovorans has been associated with a number of serious infections, including bacteremia, empyema, bacterial endocarditis, and ocular and urinary tract infections. It has also been linked with a variety of surface-associated nosocomial infections. Biofilm-forming antimicrobial-resistant D. acidovorans strains have also been isolated, including ones displaying resistance to the common broad-spectrum agent chlorhexidine. The mechanisms of chlorhexidine resistance in D. acidovorans are not known; hence, a chlorhexidine-susceptible mutant of the tolerant wild-type strain was obtained using transposon mutagenesis, and the proteome and ultrastructural changes of both strains were compared under chlorhexidine challenge.
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Karuppasamy K, Yadav AS, Saxena GK. Thermal inactivation of Salmonella Enteritidis on chicken skin previously exposed to acidified Sodium chlorite or tri-sodium phosphate. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2015; 52:8236-43. [PMID: 26604399 PMCID: PMC4648861 DOI: 10.1007/s13197-015-1922-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 10/23/2022]
Abstract
Thermal inactivation of normal and starved cells of Salmonella Enteritidis on chicken skin previously exposed to different concentrations of acidified sodium chlorite (ASC) or tri-sodium phosphate (TSP) was investigated. Inoculated skin was pretreated with different concentration of ASC or TSP, packaged in bags, and then immersed in a circulating water bath at 60 to 68 °C. The recovery medium was Hektoen enteric agar. D-values, determined by linear regression, for normal cells on chicken skin, were 2.79, 1.17 and 0.53 min whereas D-values for starved cells were 4.15, 1.83 and 0.66 at 60, 64 and 68 °C, respectively. z-values for normal cells were 3.54 and for starved cells were 2.29. Pretreatment of Salmonella Enteritidis cells with 0 to 200 ppm of ASC or 0 to 1.0 % TSP resulted in lower D-values at all temperatures. Sensory results indicated no significance differences for control and treatments. Thus, results of this study indicated that pretreatment of chicken skin with ASC or TSP increased sensitivity of Salmonella Enteritidis to heat without affecting organoleptic quality of chicken meat.
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Affiliation(s)
- K. Karuppasamy
- Food Microbiology Laboratory, Post Harvest Technology Division, ICAR-Central Avian Research Institute, Izatnagar, 243122 UP India
| | - Ajit S. Yadav
- Food Microbiology Laboratory, Post Harvest Technology Division, ICAR-Central Avian Research Institute, Izatnagar, 243122 UP India
| | - Gaurav K. Saxena
- Food Microbiology Laboratory, Post Harvest Technology Division, ICAR-Central Avian Research Institute, Izatnagar, 243122 UP India
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15
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The adaptive response of bacterial food-borne pathogens in the environment, host and food: Implications for food safety. Int J Food Microbiol 2015; 213:99-109. [DOI: 10.1016/j.ijfoodmicro.2015.06.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 05/21/2015] [Accepted: 06/08/2015] [Indexed: 11/19/2022]
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16
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Differences in Physical and Biochemical Properties of Thermus scotoductus SA-01 Cultured with Dielectric or Convection Heating. Appl Environ Microbiol 2015; 81:6285-93. [PMID: 26150459 DOI: 10.1128/aem.01618-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/28/2015] [Indexed: 02/06/2023] Open
Abstract
A thermophile, Thermus scotoductus SA-01, was cultured within a constant-temperature (65°C) microwave (MW) digester to determine if MW-specific effects influenced the growth and physiology of the organism. As a control, T. scotoductus cells were also cultured using convection heating at the same temperature as the MW studies. Cell growth was analyzed by optical density (OD) measurements, and cell morphologies were characterized using electron microscopy imaging (scanning electron microscopy [SEM] and transmission electron microscopy [TEM]), dynamic light scattering (DLS), and atomic force microscopy (AFM). Biophysical properties (i.e., turgor pressure) were also calculated with AFM, and biochemical compositions (i.e., proteins, nucleic acids, fatty acids) were analyzed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the fatty acid methyl esters extracted from cell membranes. Here we report successful cultivation of a thermophile with only dielectric heating. Under the MW conditions for growth, cell walls remained intact and there were no indications of membrane damage or cell leakage. Results from these studies also demonstrated that T. scotoductus cells grown with MW heating exhibited accelerated growth rates in addition to altered cell morphologies and biochemical compositions compared with oven-grown cells.
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17
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Genes Associated with Desiccation and Osmotic Stress in Listeria monocytogenes as Revealed by Insertional Mutagenesis. Appl Environ Microbiol 2015; 81:5350-62. [PMID: 26025900 DOI: 10.1128/aem.01134-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/22/2015] [Indexed: 12/29/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen whose survival in food processing environments may be associated with its tolerance to desiccation. To probe the molecular mechanisms used by this bacterium to adapt to desiccation stress, a transposon library of 11,700 L. monocytogenes mutants was screened, using a microplate assay, for strains displaying increased or decreased desiccation survival (43% relative humidity, 15°C) in tryptic soy broth (TSB). The desiccation phenotypes of selected mutants were subsequently assessed on food-grade stainless steel (SS) coupons in TSB plus 1% glucose (TSB-glu). Single transposon insertions in mutants exhibiting a change in desiccation survival of >0.5 log CFU/cm(2) relative to that of the wild type were determined by sequencing arbitrary PCR products. Strain morphology, motility, and osmotic stress survival (in TSB-glu plus 20% NaCl) were also analyzed. The initial screen selected 129 desiccation-sensitive (DS) and 61 desiccation-tolerant (DT) mutants, out of which secondary screening on SS confirmed 15 DT and 15 DS mutants. Among the DT mutants, seven immotile and flagellum-less strains contained transposons in genes involved in flagellum biosynthesis (fliP, flhB, flgD, flgL) and motor control (motB, fliM, fliY), while others harbored transposons in genes involved in membrane lipid biosynthesis, energy production, potassium uptake, and virulence. The genes that were interrupted in the 15 DS mutants included those involved in energy production, membrane transport, protein metabolism, lipid biosynthesis, oxidative damage control, and putative virulence. Five DT and 14 DS mutants also demonstrated similar significantly (P < 0.05) different survival relative to that of the wild type when exposed to osmotic stress, demonstrating that some genes likely have similar roles in allowing the organism to survive the two water stresses.
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18
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Yeater MC, Kirsch KR, Taylor TM, Mitchell J, Osburn WN. Effectiveness of sanitizing products on controlling selected pathogen surrogates on retail deli slicers. J Food Prot 2015; 78:707-15. [PMID: 25836395 DOI: 10.4315/0362-028x.jfp-14-400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The objectives of this study were (i) to assess the efficacy of quaternary ammonium chloride-based wet foam (WF) and dry foam (DF) sanitizer systems (600 ppm) for reducing Listeria innocua (a nonpathogenic surrogate of Listeria monocytogenes) or a 100.0 μg/ml rifampin-resistant Salmonella Typhimurium LT2 (a nonpathogenic surrogate of Salmonella enterica serovar Typhimurium) on niche and transfer point areas of an unwashed retail deli slicer as compared with traditional chlorine (Cl(-)) treatment (200 ppm) and (ii) to compare sanitizer surface contact times (10 and 15 min) for pathogen surrogate control. Turkey frankfurter slurries inoculated with L. innocua or Salmonella Typhimurium were used to inoculate seven high-risk sites on a commercial slicer. After 30 min of bacterial attachment, slicers were dry wiped to remove excess food matter, followed by a randomly assigned sanitizer treatment. Surviving pathogen surrogate cells were enumerated on modified Oxford's agar not containing antimicrobic supplement (L. innocua) or on tryptic soy agar supplemented with 100 μg/ml rifampin (Salmonella Typhimurium LT2). Replicate-specific L. innocua and Salmonella Typhimurium reductions were calculated as log CFU per square centimeter of control minus log CFU per square centimeter of enumerated survivors for each site. For both organisms, all sanitizer treatments differed from each other, with Cl(-) producing the least reduction and WF the greatest reduction. A significant (P < 0.05) site-by-treatment interaction was observed. The results of the study indicate that quaternary ammonium chloride sanitizers (600 ppm) applied by both WF and DF were more effective at reducing L. innocua and Salmonella Typhimurium than a traditional Cl sanitizer (200 ppm) on unwashed slicer surfaces.
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Affiliation(s)
- Michael C Yeater
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, Texas 77843-2471, USA
| | - Katie R Kirsch
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843-2253, USA
| | - T Matthew Taylor
- Department of Animal Science, Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, Texas 77843-2471, USA
| | - Jeff Mitchell
- Chemstar Corporation, 120 Interstate West Parkway, Lithia Springs, Georgia 30122, USA
| | - Wesley N Osburn
- Department of Animal Science, Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, Texas 77843-2471, USA.
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19
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Tolerance of Salmonella enterica serovar Typhimurium to nisin combined with EDTA is accompanied by changes in cellular composition. Food Res Int 2015. [DOI: 10.1016/j.foodres.2014.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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20
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Yang Y, Kadim MI, Khoo WJ, Zheng Q, Setyawati MI, Shin YJ, Lee SC, Yuk HG. Membrane lipid composition and stress/virulence related gene expression of Salmonella Enteritidis cells adapted to lactic acid and trisodium phosphate and their resistance to lethal heat and acid stress. Int J Food Microbiol 2014; 191:24-31. [DOI: 10.1016/j.ijfoodmicro.2014.08.034] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/23/2014] [Accepted: 08/26/2014] [Indexed: 01/20/2023]
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21
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Xu M, Wang J, Mou H. Fatty acid profiles ofVibrio parahaemolyticusand its changes with environment. J Basic Microbiol 2013; 55:112-20. [DOI: 10.1002/jobm.201300496] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/10/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Min Xu
- College of Food Science and Engineering; Ocean University of China; Qingdao China
| | - Jing Wang
- College of Food Science and Engineering; Ocean University of China; Qingdao China
| | - Haijin Mou
- College of Food Science and Engineering; Ocean University of China; Qingdao China
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22
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Lu S, Han Y, Duan X, Luo F, Zhu L, Li S, Huang H. Cell Morphology Variations of Klebsiella pneumoniae Induced by Acetate Stress Using Biomimetic Vesicle Assay. Appl Biochem Biotechnol 2013; 171:731-43. [DOI: 10.1007/s12010-013-0368-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/23/2013] [Indexed: 10/26/2022]
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Nasri K, Daghfous D, Landoulsi A. Effects of microwave (2.45 GHz) irradiation on some biological characters of Salmonella typhimurium. C R Biol 2013; 336:194-202. [PMID: 23849722 DOI: 10.1016/j.crvi.2013.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
The present study was carried out to evaluate the effects of sub-lethal doses of microwave radiation on some biological characteristics in Salmonella typhimurium. The aim was to show the relationship between this treatment and the development of radiotolerance in this pathogen because there is a need for more information on physiological responses of pathogens to sub-lethal doses of microwave radiation. So, the bacterial strain was treated with a dose of 3600J (40-s exposure with power P=90 W) to cause cellular damage. The results have shown that the exposure of bacteria to microwaves resulted in a significant inhibition of cellular growth. This treatment has notably increased the effectiveness of the most tested antibiotics by the amelioration or the appearance of sensitivity in exposed bacteria. Gas chromatography (GC) analysis was performed to demonstrate the modification of the fatty acids (FA) composition. Results obtained have shown that this treatment had a significant effect on the FA content with an increase of unsaturated FA percentage. The acquisition of sensitivity to the sodium deoxycholate and the significant increase in the amount of extracellular proteins in exposed bacteria has confirmed the weakening of the bacterial membrane by microwaves. This study represents one of the few demonstrating the modifications on the bacterial membrane as a cellular response to survive the non-ionising radiation stress.
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Affiliation(s)
- Kaouther Nasri
- Laboratoire de biochimie et biologie moléculaire, faculté des sciences de Bizerte, 7021 Zarzouna, Tunisia.
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24
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Lagha R, Ben Abdallah F, Ellafi A, Békir K, Bakhrouf A. Biofilm Formation, Cell Surface Hydrophobicity, and Fatty Acids Analysis of StarvedSalmonella entericaSerovar Typhimurium in Seawater. Foodborne Pathog Dis 2012; 9:786-91. [DOI: 10.1089/fpd.2012.1129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Rihab Lagha
- Laboratoire d'Analyse, Traitement et Valorisation des Polluants de l'Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir, Tunisia
| | - Fethi Ben Abdallah
- Laboratoire d'Analyse, Traitement et Valorisation des Polluants de l'Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir, Tunisia
| | - Ali Ellafi
- Laboratoire d'Analyse, Traitement et Valorisation des Polluants de l'Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir, Tunisia
| | - Karima Békir
- Laboratoire d'Analyse, Traitement et Valorisation des Polluants de l'Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir, Tunisia
| | - Amina Bakhrouf
- Laboratoire d'Analyse, Traitement et Valorisation des Polluants de l'Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir, Tunisia
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25
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Mihoub M, El May A, Aloui A, Chatti A, Landoulsi A. Effects of static magnetic fields on growth and membrane lipid composition of Salmonella typhimurium wild-type and dam mutant strains. Int J Food Microbiol 2012; 157:259-66. [PMID: 22682582 DOI: 10.1016/j.ijfoodmicro.2012.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 04/22/2012] [Accepted: 05/18/2012] [Indexed: 01/12/2023]
Abstract
This study was carried out to explore the adaptive mechanisms of S. typhimurium particularly, the implication of the Dam methyltransferase in the remodelling of membrane lipid composition to overcome magnetic field stress. With this aim, we focused our analyses on the increase in viable numbers and membrane lipid modifications of S. typhimurium wild-type and dam mutant cells exposed for 10h to static magnetic fields (SMF; 200 mT). For the wild-type strain, exposure to SMF induced a significant decrease (p<0.05) of CFU at 6h, followed by an increase between 8 and 10h. Growth of the dam mutant was significantly affected (p<0.05) after 6h and no recovery was observed until 10h, highlighting a different behavior of SMF stressed wild-type and dam mutant strains. SMF significantly affected the phospholipid proportions in the two strains. The most affected were those of the acidic phospholipids, cardiolipins (CL). In the dam strain the phospholipid response to SMF followed a globally similar trend as in the wild-type with however lower effects, leading mainly to an unusual accumulation of CL. This would in part explain the different behavior of the wild-type and the dam strain. Results showed a significant increase of membrane cyclic fatty acids Cyc17 and Cyc19 in the wild-type strain but only the Cyc17 in the dam strain and a meaningful increase of the total unsaturated fatty acids (UFAs) to total saturated fatty acids (SFAs) ratios of the exposed cells compared to controls from 3 to 9h (p<0.05) for both strains. The net increase of the total UFAs to total SFAs ratios seemed to result mainly from the increase of (C18:1) proportion (p<0.05) and to a lower extent from that of (C16:1) (p<0.05). These modifications of cyclic and unsaturated fatty acid proportions constitute an adaptive response to SMF stress in S. typhimurium wild-type and dam mutants to maintain an optimum level of membrane fluidity under SMF.
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Affiliation(s)
- Mouadh Mihoub
- Unité de Biochimie des Lipides et Interaction des Macromolécules en Biologie (03/UR/0902), Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Bizerte, Tunisia.
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26
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Abstract
The highly alkaline compound trisodium phosphate (TSP) is used as an intervention to reduce the load of Campylobacter on poultry meat in U.S. poultry slaughter plants. The aim of the present study was to investigate the cellular responses of Campylobacter jejuni NCTC11168 when exposed to sublethal concentrations of TSP. Preexposure of C. jejuni to TSP resulted in a significant increase in heat sensitivity, suggesting that a combined heat and TSP treatment may increase reduction of C. jejuni. A microarray analysis identified a limited number of genes that were differently expressed after sublethal TSP exposure; however, the response was mainly associated with ion transport processes. C. jejuni NCTC11168 nhaA1 (Cj1655c) and nhaA2 (Cj1654c), which encode orthologues to the Escherichia coli NhaA cation/proton antiporter, were able to partially restore TSP, alkaline, and sodium resistance phenotypes to an E. coli cation/proton antiporter mutant. In addition, inhibition of resistance-nodulation-cell division (RND) multidrug efflux pumps by the inhibitor PaβN (Phe-Arg β-naphthylamide dihydrochloride) decreased tolerance to sublethal TSP. Therefore, we propose that NhaA1/NhaA2 cation/proton antiporters and RND multidrug efflux pumps function in tolerance to sublethal TSP exposure in C. jejuni.
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27
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Insights into the pH up-shift responsive mechanism of Acidithiobacillus ferrooxidans by microarray transcriptome profiling. Folia Microbiol (Praha) 2011; 56:439-51. [DOI: 10.1007/s12223-011-0067-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Accepted: 08/28/2011] [Indexed: 10/17/2022]
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28
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ÁLVAREZ-ORDÓÑEZ AVELINO, FERNÁNDEZ ANA, BERNARDO ANA, LÓPEZ MERCEDES. EFFICACY OF TRISODIUM PHOSPHATE IN KILLING ACID-ADAPTED SALMONELLA TYPHIMURIUM. J Food Saf 2011. [DOI: 10.1111/j.1745-4565.2010.00293.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Alvarez-Ordóñez A, Prieto M. Changes in ultrastructure and Fourier transform infrared spectrum of Salmonella enterica serovar typhimurium cells after exposure to stress conditions. Appl Environ Microbiol 2010; 76:7598-607. [PMID: 20851964 PMCID: PMC2976207 DOI: 10.1128/aem.00312-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 09/08/2010] [Indexed: 11/20/2022] Open
Abstract
The effect of exposure to acid (pH 2.5), alkaline (pH 11.0), heat (55°C), and oxidative (40 mM H₂O₂) lethal conditions on the ultrastructure and global chemical composition of Salmonella enterica serovar Typhimurium CECT 443 cells was studied using transmission electron microscopy and Fourier transform infrared spectroscopy (FT-IR) combined with multivariate statistical methods (hierarchical cluster analysis and factor analysis). Infrared spectra exhibited marked differences in the five spectral regions for all conditions tested compared to those of nontreated control cells, which suggests the existence of a complex bacterial stress response in which modifications in a wide variety of cellular compounds are involved. The visible spectral changes observed in all of the spectral regions, together with ultrastructural changes observed by transmission electron microscopy and data obtained from membrane integrity tests, indicate the existence of membrane damage or alterations in membrane composition after heat, acid, alkaline, and oxidative treatments. Results obtained in this study indicate the potential of FT-IR spectroscopy to discriminate between intact and injured bacterial cells and between treatment technologies, and they show the adequacy of this technique to study the molecular aspects of bacterial stress response.
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Affiliation(s)
- A. Alvarez-Ordóñez
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, 24071 León, Spain
| | - M. Prieto
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, 24071 León, Spain
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30
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Ayari S, Dussault D, Millette M, Hamdi M, Lacroix M. Response of Bacillus cereus to gamma-irradiation in combination with carvacrol or mild heat treatment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:8217-8224. [PMID: 20568774 DOI: 10.1021/jf101044f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Carvacrol and mild heat treatment were tested for their efficiency to increase the radiosensitivity of Bacillus cereus in broth. The bacterium was treated with gamma-irradiation alone or in combination with carvacrol at its minimal inhibitory concentration or mild heat treatment for 10 min at 45 degrees C. The effects of this combination of treatments were studied on various parameters: the bacterial viability, the modifications of the cell morphology with scanning electron microscopy (SEM), the cellular fatty acids composition of the membrane quantified by gas chromatography, the intracellular and extracellular adenosine 5'-triphosphate (ATP) concentrations, and the DNA degradation. Combined treatments resulted in additive or synergistic effects as compared to gamma-irradiation alone. A significant modification (P < or = 0.05) of the fatty acid composition and unsaturation ratios was observed. Pretreatment with mild heat or carvacrol before irradiation disturbed the membrane integrity of B. cereus and induced a significant decrease (P < or = 0.05) of the intracellular ATP concentration. SEM observations revealed that the cell membrane was more severely affected with combined treatment than irradiation alone. The electrophoresis analysis showed that DNA degradation by combined treatments was greater than the gamma-irradiation alone.
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Affiliation(s)
- Samia Ayari
- National Center for Nuclear Sciences and Technologies, Tunis Cedex, Tunisia
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31
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Aloui A, Mihoub M, Sethom MM, Chatti A, Feki M, Kaabachi N, Landoulsi A. Effects ofdamand/orseqAMutations on the Fatty Acid and Phospholipid Membrane Composition ofSalmonella entericaSerovar Typhimurium. Foodborne Pathog Dis 2010; 7:573-83. [DOI: 10.1089/fpd.2009.0385] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Amine Aloui
- Biochemistry Unit of Lipids and Interactions of Macromolecules in Biology, Laboratory of Biochemistry and Molecular Biology, Faculty of Sciences of Bizerte, Zarzouna, Tunisia
| | - Mouadh Mihoub
- Biochemistry Unit of Lipids and Interactions of Macromolecules in Biology, Laboratory of Biochemistry and Molecular Biology, Faculty of Sciences of Bizerte, Zarzouna, Tunisia
| | | | - Abdelwaheb Chatti
- Biochemistry Unit of Lipids and Interactions of Macromolecules in Biology, Laboratory of Biochemistry and Molecular Biology, Faculty of Sciences of Bizerte, Zarzouna, Tunisia
| | - Moncef Feki
- Research Laboratory, Biochemistry Department, LaRabta Hospital, Tunis, Tunisia
| | - Naziha Kaabachi
- Research Laboratory, Biochemistry Department, LaRabta Hospital, Tunis, Tunisia
| | - Ahmed Landoulsi
- Biochemistry Unit of Lipids and Interactions of Macromolecules in Biology, Laboratory of Biochemistry and Molecular Biology, Faculty of Sciences of Bizerte, Zarzouna, Tunisia
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32
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Alonso-Hernando A, Alonso-Calleja C, Capita R. Effects of exposure to poultry chemical decontaminants on the membrane fluidity of Listeria monocytogenes and Salmonella enterica strains. Int J Food Microbiol 2010; 137:130-6. [DOI: 10.1016/j.ijfoodmicro.2009.11.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 11/18/2009] [Accepted: 11/25/2009] [Indexed: 10/20/2022]
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Mangalappalli-Illathu AK, Lawrence JR, Korber DR. Cells in shearable and nonshearable regions of Salmonella enterica serovar Enteritidis biofilms are morphologically and physiologically distinct. Can J Microbiol 2009; 55:955-66. [PMID: 19898535 DOI: 10.1139/w09-048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cellular morphology, exopolymer chemistry, and protein expression of shearable and nonshearable fractions of Salmonella enterica serovar Enteritidis biofilms were examined. Biofilms were grown at a laminar flow velocity of 0.07 cm.s-1 for ~120 h, resulting in biofilms with a thickness (mean +/- SD) of 43 +/- 24 microm. An empirically determined shear-inducing flow (1.33 cm.s-1) was then applied for 5 min, effectively reducing biofilm thickness by ~70% and leaving 13 +/- 6 microm of nonshearable material and allowing fractionation of biofilm material into shearable and nonshearable regions. In situ lectin binding analyses revealed that there was no significant difference in the exopolymer glycoconjugate composition of the shearable and nonshearable biofilm zones. Length to width indices of cells from nonshearable and shearable biofilm regions as well as planktonic cells from biofilm effluent and continuous culture were determined to be 3.2, 2.3, 2.2, and 1.7, respectively, indicating that the cells in the shearable fraction were morphologically more similar to planktonic cells than the cells in the nonshearable biofilm fraction. Enhanced expression of proteins involved in cold shock response, adaptation, and broad regulatory functions (CspA, GrcA, and Hns, respectively) in cells from the shearable region as well as protein translation and modification and enhanced expression of protein involved in heat shock response and chaperonin function (DnaK) in cells from the nonshearable region revealed that the physiological status of cells in the two biofilm regions was distinct. This was also reflected in the different morphologies of cells from the two biofilm zones. Stratified patterns of cell metabolism and morphology in biofilms, obtained using shear-induced biofilm fractionation, may yield important information of how cells of deeply embedded biofilm bacteria survive imposed conditions of stress such as treatment with antimicrobial agents or antibiotics.
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Han YH, Liu WZ, Shi YZ, Lu LQ, Xiao SD, Zhang QH. Gene expression profile of Helicobacter pylori in response to growth temperature variation. J Microbiol 2009; 47:455-65. [PMID: 19763420 DOI: 10.1007/s12275-009-0003-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Accepted: 04/03/2009] [Indexed: 02/07/2023]
Abstract
A Helicobacter pylori whole-genome DNA microarray was constructed to study expression profiles of H. pylori in response to a sudden temperature transfer from 37 degrees C to 20 degrees C. The expression level of the genome at each of four time points (15, 30, 60, and 120 min) after temperature downshift was compared with that just before cold treatment. Globally, 10.2 % (n=167) of the total predicted H. pylori genes (n=1636) represented on the microarray were significantly differentially expressed (p<0.05) over a 120 min period after shift to low temperature. The expression profiles of the differentially expressed genes were grouped, and their expression patterns were validated by quantitative real-time PCR. Up-regulated genes mainly included genes involved in energy metabolism and substance metabolism, cellular processes, protein fate, ribosomal protein genes, and hypothetical protein genes, which indicate the compensational responses of H. pylori to temperature downshift. Those genes play important roles in adaption to temperature downshift of H. pylori. Down-regulation of DNA metabolism genes and cell envelope genes and cellular processes genes may reflect damaged functions under low temperature, which is unfavorable to bacterial infection and propagation. Overall, this time-course study provides new insights into the primary response of H. pylori to a sudden temperature downshift, which allow the bacteria to survive and adapt to the new host environment.
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Affiliation(s)
- Yue-hua Han
- Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, P. R. China.
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Fernández A, Álvarez-Ordóñez A, López M, Bernardo A. Effects of organic acids on thermal inactivation of acid and cold stressed Enterococcus faecium. Food Microbiol 2009; 26:497-503. [DOI: 10.1016/j.fm.2009.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 03/05/2009] [Accepted: 03/10/2009] [Indexed: 10/21/2022]
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Álvarez-Ordóñez A, Fernández A, López M, Bernardo A. Relationship between membrane fatty acid composition and heat resistance of acid and cold stressed Salmonella senftenberg CECT 4384. Food Microbiol 2009; 26:347-53. [DOI: 10.1016/j.fm.2008.11.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 11/14/2008] [Accepted: 11/15/2008] [Indexed: 11/25/2022]
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Differential adaptive response and survival of Salmonella enterica serovar enteritidis planktonic and biofilm cells exposed to benzalkonium chloride. Antimicrob Agents Chemother 2008; 52:3669-80. [PMID: 18663028 DOI: 10.1128/aac.00073-08] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study examined the adaptive response and survival of planktonic and biofilm phenotypes of Salmonella enterica serovar Enteritidis adapted to benzalkonium chloride (BC). Planktonic cells and biofilms were continuously exposed to 1 microg ml(-1) of BC for 144 h. The proportion of BC-adapted biofilm cells able to survive a lethal BC treatment (30 microg ml(-1)) was significantly higher (4.6-fold) than that of BC-adapted planktonic cells. Similarly, there were 18.3-fold more survivors among the BC-adapted biofilm cells than among their nonadapted (i.e., without prior BC exposure) cell counterparts at the lethal BC concentration, and this value was significantly higher than the value for BC-adapted planktonic cells versus nonadapted cells (3.2-fold). A significantly higher (P < 0.05) proportion of surviving cells was noticed among BC-adapted biofilm cells relative to BC-adapted planktonic cells following a 10-min heat shock at 55 degrees C. Fatty acid composition was significantly influenced by phenotype (planktonic cells or biofilm) and BC adaptation. Cell surface roughness of biofilm cells was also significantly greater (P < 0.05) than that of planktonic cells. Key proteins upregulated in BC-adapted planktonic and biofilm cells included CspA, TrxA, Tsf, YjgF, and a probable peroxidase, STY0440. Nine and 17 unique proteins were upregulated in BC-adapted planktonic and biofilm cells, respectively. These results suggest that enhanced biofilm-specific upregulation of 17 unique proteins, along with the increased expression of CspA, TrxA, Tsf, YjgF, and a probable peroxidase, phenotype-specific alterations in cell surface roughness, and a shift in fatty acid composition conferred enhanced survival to the BC-adapted biofilm cell population relative to their BC-adapted planktonic cell counterparts.
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Assessment of the possible effect of the four antimicrobial treatment substances on the emergence of antimicrobial resistance - Scientific Opinion of the Panel on Biological Hazards. EFSA J 2008. [DOI: 10.2903/j.efsa.2008.659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Álvarez-Ordóñez A, Fernández A, López M, Arenas R, Bernardo A. Modifications in membrane fatty acid composition of Salmonella typhimurium in response to growth conditions and their effect on heat resistance. Int J Food Microbiol 2008; 123:212-9. [DOI: 10.1016/j.ijfoodmicro.2008.01.015] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 01/29/2008] [Accepted: 01/30/2008] [Indexed: 10/22/2022]
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40
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Mangalappalli-Illathu AK, Korber DR. Adaptive resistance and differential protein expression of Salmonella enterica serovar Enteritidis biofilms exposed to benzalkonium chloride. Antimicrob Agents Chemother 2006; 50:3588-96. [PMID: 16940079 PMCID: PMC1635200 DOI: 10.1128/aac.00573-06] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 06/02/2006] [Accepted: 08/18/2006] [Indexed: 01/05/2023] Open
Abstract
The development of adaptive resistance of Salmonella enterica serovar Enteritidis ATCC 4931 biofilms following exposure to benzalkonium chloride (BC) either continuously (1 microg ml(-1)) or intermittently (10 microg ml(-1) for 10 min daily) was examined. Biofilms adapted to BC over a 144-h period could survive a normally lethal BC challenge (500 microg ml(-1) for 10 min) and then regrow, as determined by increases in biofilm thickness, total biomass, and the ratio of the viable biomass to the nonviable biomass. Exposure of untreated control biofilms to the lethal BC challenge resulted in biofilm erosion and cell death. Proteins found to be up-regulated following BC adaptation were those involved in energy metabolism (TpiA and Eno), amino acid and protein biosynthesis (WrbA, TrxA, RplL, Tsf, Tuf, DsbA, and RpoZ), nutrient binding (FruB), adaptation (CspA), detoxification (Tpx, SodB, and a probable peroxidase), and degradation of 1,2-propanediol (PduJ and PduA). A putative universal stress protein (YnaF) was also found to be up-regulated. Proteins involved in proteolysis (DegQ), cell envelope formation (RfbH), adaptation (UspA), heat shock response (DnaK), and broad regulatory functions (Hns) were found to be down-regulated following adaptation. An overall increase in cellular protein biosynthesis was deduced from the significant up-regulation of ribosomal subunit proteins, translation elongation factors, and amino acid biosynthesis protein and down-regulation of serine endoprotease. The cold shock response, stress response, and detoxification are suggested to play roles in the adaptive resistance of Salmonella serovar Enteritidis biofilms to BC.
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Affiliation(s)
- Anil K Mangalappalli-Illathu
- Department of Applied Microbiology and Food Science, 51 Campus Dr., University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
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Abstract
The transcriptional regulation of membrane fatty acid composition in the human pathogen Streptococcus pneumoniae is distinct from the systems utilized in the model organisms Escherichia coli and Bacillus subtilis. The genes encoding the components of type II fatty acid biosynthesis cluster at a single location within the S. pneumoniae genome, and the second gene in this cluster (SPR0376) encodes a transcription factor (FabT) that belongs to the MarR superfamily. Derivatives of S. pneumoniae strain D39 were constructed that lacked functional FabT. This strain had significantly elevated levels of saturated fatty acids and longer chain lengths than the control strain, was unable to grow at pH 5.5 and had increased sensitivity to detergent. Eliminating FabT function increased the expression levels of all of fab genes with the notable exception of fabM. FabT was purified and bound to the DNA palindrome located within the promoter regions of the fabT and fabK genes within the cluster. The analysis of cells with increased expression of individual genes leads to a model where the physical properties of the S. pneumoniae membrane is controlled primarily by the activity of FabK, the enoyl reductase, which diverts intermediates to saturated fatty acid formation, in contrast to E. coli where FabB, an elongation condensing enzyme, pulls the pathway in the direction of unsaturated acid synthesis.
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Affiliation(s)
- Ying-Jie Lu
- Department of Infectious Diseases, St. Jude Children's Hospital, Memphis, TN 38105-2794, USA
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Di Pasqua R, Hoskins N, Betts G, Mauriello G. Changes in membrane fatty acids composition of microbial cells induced by addiction of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol in the growing media. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:2745-9. [PMID: 16569070 DOI: 10.1021/jf052722l] [Citation(s) in RCA: 281] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Major active compounds from essential oils are well-known to possess antimicrobial activity against both pathogen and spoilage microorganisms. The aim of this work was to determine the alteration of the membrane fatty acid profile as an adaptive mechanism of the cells in the presence of a sublethal concentration of antimicrobial compound in response to a stress condition. Methanolic solutions of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol were added into growth media of Escherichia coli O157:H7, Salmonella enterica serovar typhimurium, Pseudomonas fluorescens, Brochothrix thermosphacta, and Staphylococcus aureus strains. Fatty acid extraction and gas chromatographic analysis were performed to assess changes in membrane fatty acid composition. Substantial changes were observed on the long chain unsaturated fatty acids when the E. coli and Salmonella strains grew in the presence of limonene and cinnamaldehyde and carvacrol and eugenol, respectively. All compounds influenced the fatty acid profile of B. thermosphacta, while Pseudomonas and S. aureus strains did not show substantial changes in their fatty acid compositions.
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Affiliation(s)
- Rosangela Di Pasqua
- Department of Food Science, Division of Microbiology, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
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Sampathkumar B, Napper S, Carrillo CD, Willson P, Taboada E, Nash JHE, Potter AA, Babiuk LA, Allan BJ. Transcriptional and translational expression patterns associated with immobilized growth of Campylobacter jejuni. Microbiology (Reading) 2006; 152:567-577. [PMID: 16436444 DOI: 10.1099/mic.0.28405-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AlthoughCampylobacter jejuniis a leading cause of food-borne illness, little is known about the mechanisms by which this pathogen mediates prolonged environmental survival or host cell virulence. Although these behaviours represent distinct phenotypes, they share a common requirement of an immobilized state. In order to understand the cellular mechanisms that facilitate a surface-associated lifestyle, transcriptional and translational expression profiles were determined for sessile and planktonicC. jejuni. These investigations indicate that the immobilized bacteria undergo a shift in cellular priorities away from metabolic, motility and protein synthesis capabilities towards emphasis on iron uptake, oxidative stress defence and membrane transport. This pattern of expression partially overlaps those reported for Campylobacter during host colonization, as well as for other species of bacteria involved in biofilms, highlighting common adaptive responses to the conserved challenges within each of these phenotypes. The adaptation of Campylobacter to immobilized growth may represent a quasi-differentiated state that functions as a foundation for further specialization towards phenotypes such as biofilm formation or host cell virulence.
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Affiliation(s)
- Balamurugan Sampathkumar
- Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C&E Trail, Lacombe, Alberta, Canada T4L 1W1
| | - Scott Napper
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
| | - Catherine D Carrillo
- Institute for Biological Sciences, National Research Council of Canada, 100 Sussex Road, Ottawa, Ontario, Canada K1A 0R6
| | - Philip Willson
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
| | - Eduardo Taboada
- Institute for Biological Sciences, National Research Council of Canada, 100 Sussex Road, Ottawa, Ontario, Canada K1A 0R6
| | - John H E Nash
- Institute for Biological Sciences, National Research Council of Canada, 100 Sussex Road, Ottawa, Ontario, Canada K1A 0R6
| | - Andrew A Potter
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
| | - Lorne A Babiuk
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
| | - Brenda J Allan
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
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