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Van Eldijk TJB, Sheridan EA, Martin G, Weissing FJ, Kuipers OP, Van Doorn GS. Temperature dependence of the mutation rate towards antibiotic resistance. JAC Antimicrob Resist 2024; 6:dlae085. [PMID: 38847007 PMCID: PMC11154133 DOI: 10.1093/jacamr/dlae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/14/2024] [Indexed: 06/09/2024] Open
Abstract
Objectives Environmental conditions can influence mutation rates in bacteria. Fever is a common response to infection that alters the growth conditions of infecting bacteria. Here we examine how a temperature change, such as is associated with fever, affects the mutation rate towards antibiotic resistance. Methods We used a fluctuation test to assess the mutation rate towards antibiotic resistance in Escherichia coli at two different temperatures: 37°C (normal temperature) and 40°C (fever temperature). We performed this measurement for three different antibiotics with different modes of action: ciprofloxacin, rifampicin and ampicillin. Results In all cases, the mutation rate towards antibiotic resistance turned out to be temperature dependent, but in different ways. Fever temperatures led to a reduced mutation rate towards ampicillin resistance and an elevated mutation rate towards ciprofloxacin and rifampicin resistance. Conclusions This study shows that the mutation rate towards antibiotic resistance is impacted by a small change in temperature, such as associated with fever. This opens a new avenue to mitigate the emergence of antibiotic resistance by coordinating the choice of an antibiotic with the decision of whether or not to suppress fever when treating a patient. Hence, optimized combinations of antibiotics and fever suppression strategies may be a new weapon in the battle against antibiotic resistance.
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Affiliation(s)
- Timo J B Van Eldijk
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
- Department of Medical Microbiology and Virology, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Eleanor A Sheridan
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Guillaume Martin
- Institut des Sciences de l’Evolution de Montpellier UMR5554, Université de Montpellier, CNRS-IRD-EPHE-UM, Montpellier, France
| | - Franz J Weissing
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Oscar P Kuipers
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - G Sander Van Doorn
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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2
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Gao T, Niu L, Wu X, Dai D, Zhou Y, Liu M, Wu K, Yu Y, Guan N, Ye H. Sonogenetics-controlled synthetic designer cells for cancer therapy in tumor mouse models. Cell Rep Med 2024; 5:101513. [PMID: 38608697 PMCID: PMC11148564 DOI: 10.1016/j.xcrm.2024.101513] [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: 08/10/2023] [Revised: 02/21/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024]
Abstract
Bacteria-based therapies are powerful strategies for cancer therapy, yet their clinical application is limited by a lack of tunable genetic switches to safely regulate the local expression and release of therapeutic cargoes. Rapid advances in remote-control technologies have enabled precise control of biological processes in time and space. We developed therapeutically active engineered bacteria mediated by a sono-activatable integrated gene circuit based on the thermosensitive transcriptional repressor TlpA39. Through promoter engineering and ribosome binding site screening, we achieved ultrasound (US)-induced protein expression and secretion in engineered bacteria with minimal noise and high induction efficiency. Specifically, delivered either intratumorally or intravenously, engineered bacteria colonizing tumors suppressed tumor growth through US-irradiation-induced release of the apoptotic protein azurin and an immune checkpoint inhibitor, a nanobody targeting programmed death-ligand 1, in different tumor mouse models. Beyond developing safe and high-performance designer bacteria for tumor therapy, our study illustrates a sonogenetics-controlled therapeutic platform that can be harnessed for bacteria-based precision medicine.
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Affiliation(s)
- Tian Gao
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Lingxue Niu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Xin Wu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China; The Radiology Department of Shanxi Provincial People's Hospital, The Fifth Hospital of Shanxi Medical University, Taiyuan 030001, China
| | - Di Dai
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Yang Zhou
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China; Wuhu Hospital, Health Science Center, East China Normal University, Middle Jiuhua Road 263, Wuhu City, China
| | - Mengyao Liu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Ke Wu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Yuanhuan Yu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Ningzi Guan
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China.
| | - Haifeng Ye
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai 200241, China; Wuhu Hospital, Health Science Center, East China Normal University, Middle Jiuhua Road 263, Wuhu City, China.
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3
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Xiao X, Lu H, Zhu W, Zhang Y, Huo X, Yang C, Xiao S, Zhang Y, Su J. A Novel Antimicrobial Peptide Derived from Bony Fish IFN1 Exerts Potent Antimicrobial and Anti-Inflammatory Activity in Mammals. Microbiol Spectr 2022; 10:e0201321. [PMID: 35289673 PMCID: PMC9045357 DOI: 10.1128/spectrum.02013-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/15/2022] [Indexed: 11/22/2022] Open
Abstract
Type I interferons (IFN-Is) are critical antiviral cytokine in innate immunity but with limited direct defense ability against bacterial infections in mammals. In bony fish, despite all the IFN-Is (IFN1-4) act in antiviral immunity, studies demonstrate that IFN1 can remarkably contribute to host defense against bacterial infections. In this study, we found that IFN1 from grass carp (Ctenopharyngodon idella) contains an unusual cationic and amphipathic α-helical region (named as gcIFN-20, sequence: SYEKKINRHFKILKKNLKKK). The synthesized peptide gcIFN-20 could form α-helical structure in a membrane environment and exerts potent antimicrobial activity against multiple species of Gram-negative (G-) and Gram-positive (G+) bacteria with negligible toxicity. Mechanism studies showed gcIFN-20 kills G+ bacteria through membrane disruption and cytoplasm outflow while G- bacteria through membrane permeation and protein synthesis inhibition. In two mouse bacterial infection models, gcIFN-20 therapy could significantly reduce tissue bacterial loads and mortalities. In addition to the direct antibacterial activity, we also found that gcIFN-20 could significantly suppress the lipopolysaccharide (LPS)-induced pro-inflammatory cytokines in vitro and in vivo, obviously alleviated lung lesions in a mouse endotoxemia model. The mechanism is that gcIFN-20 interacts with LPS, causes LPS aggregation and neutralization. The antimicrobial and anti-inflammatory activities in vivo of gcIFN-20 in mammalian models suggested a promising agent for developing peptide-based antibacterial therapy. IMPORTANCE Type I interferons play crucial role in antiviral immunity in both vertebrates and invertebrates. The powerful antimicrobial activity is recently reported in nonmammalian vertebrates. The present study identified a novel antimicrobial peptide (gcIFN-20) derived from grass carp interferon 1, found gcIFN-20 exhibits forceful bactericidal and anti-inflammatory activity in mammals, and efficient therapeutic effect against two clinical severe extraintestinal pathogenic Escherichia coli and a mouse endotoxemia models. The antimicrobial mechanisms are membrane disruption and cytoplasm overflow for Gram-positive bacteria, while membrane permeation and protein synthesis inhibition for Gram-negative bacteria. The anti-inflammatory mechanisms can be aggregating and neutralizing lipopolysaccharide to attenuate the binding with receptors and facilitate phagocytosis. The results indicate that gcIFN-20 can be a promising novel therapeutic agent for bacterial diseases and inflammatory disorders, especially as a potential weapon for multidrug resistant strain infections.
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Affiliation(s)
- Xun Xiao
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Hao Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Wentao Zhu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Yanqi Zhang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Xingchen Huo
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Chunrong Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Shaobo Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yongan Zhang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, China
| | - Jianguo Su
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Hubei Hongshan Laboratory, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, China
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Matsumoto A, Schlüter T, Melkonian K, Takeda A, Nakagami H, Mine A. A versatile Tn 7 transposon-based bioluminescence tagging tool for quantitative and spatial detection of bacteria in plants. PLANT COMMUNICATIONS 2022; 3:100227. [PMID: 35059625 PMCID: PMC8760037 DOI: 10.1016/j.xplc.2021.100227] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 06/24/2021] [Accepted: 07/19/2021] [Indexed: 06/14/2023]
Abstract
Investigation of plant-bacteria interactions requires quantification of in planta bacterial titers by means of cumbersome and time-consuming colony-counting assays. Here, we devised a broadly applicable tool for bioluminescence-based quantitative and spatial detection of bacteria in plants. We developed vectors that enable Tn7 transposon-mediated integration of the luxCDABE luciferase operon into a specific genomic location found ubiquitously across bacterial phyla. These vectors allowed for the generation of bioluminescent transformants of various plant pathogenic bacteria from the genera Pseudomonas, Rhizobium (Agrobacterium), and Ralstonia. Direct luminescence measurements of plant tissues inoculated with bioluminescent Pseudomonas syringae pv. tomato DC3000 (Pto-lux) reported bacterial titers as accurately as conventional colony-counting assays in Arabidopsis thaliana, Solanum lycopersicum, Nicotiana benthamiana, and Marchantia polymorpha. We further showed the usefulness of our vectors in converting previously generated Pto derivatives to isogenic bioluminescent strains. Importantly, quantitative bioluminescence assays using these Pto-lux strains accurately reported the effects of plant immunity and bacterial effectors on bacterial growth, with a dynamic range of four orders of magnitude. Moreover, macroscopic bioluminescence imaging illuminated the spatial patterns of Pto-lux growth in/on inoculated plant tissues. In conclusion, our vectors offer untapped opportunities to develop bioluminescence-based assays for a variety of plant-bacteria interactions.
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Affiliation(s)
- Ayumi Matsumoto
- Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan
| | - Titus Schlüter
- Basic Immune System of Plants, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany
| | - Katharina Melkonian
- Basic Immune System of Plants, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany
| | - Atsushi Takeda
- College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Hirofumi Nakagami
- Basic Immune System of Plants, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany
| | - Akira Mine
- College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan
- JST PRESTO, Kawaguchi-shi, Saitama 332-0012, Japan
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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5
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Yang M, Yang F, Chen W, Liu S, Qiu L, Chen J. Bacteria-mediated cancer therapies: opportunities and challenges. Biomater Sci 2021; 9:5732-5744. [PMID: 34313267 DOI: 10.1039/d1bm00634g] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In recent years, cancer therapy strategies utilizing live tumor-targeting bacteria have presented unique advantages. Engineered bacteria have the particular ability to distinguish tumors from normal tissues with less toxicity. Live bacteria are naturally capable of homing to tumors, resulting in high levels of local colonization because of insufficient oxygen and low pH in the tumor microenvironment. Bacteria initiate their antitumor effects by directly killing the tumor or by activating innate and adaptive antitumor immune responses. The bacterial vectors can be reprogrammed following advanced DNA synthesis, sophisticated genetic bioengineering, and biosensors to engineer microorganisms with complex functions, and then produce and deliver anticancer agents based on clinical needs. However, because of the lack of knowledge on the mechanisms and side effects of microbial cancer therapy, developing such smart microorganisms to treat or prevent cancer remains a significant challenge. In this review, we summarized the potential, status, opportunities and challenges of this growing field. We illustrated the mechanism of tumor regression induced by engineered bacteria and discussed the recent advances in the application of bacteria-mediated cancer therapy to improve efficacy, safety and drug delivery. Finally, we shared our insights into the future directions of tumor-targeting bacteria in cancer therapy.
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Affiliation(s)
- Meiyang Yang
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China.
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6
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Singer JR, Blosser EG, Zindl CL, Silberger DJ, Conlan S, Laufer VA, DiToro D, Deming C, Kumar R, Morrow CD, Segre JA, Gray MJ, Randolph DA, Weaver CT. Preventing dysbiosis of the neonatal mouse intestinal microbiome protects against late-onset sepsis. Nat Med 2019; 25:1772-1782. [PMID: 31700190 DOI: 10.1038/s41591-019-0640-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Late-onset sepsis (LOS) is thought to result from systemic spread of commensal microbes from the intestines of premature infants. Clinical use of probiotics for LOS prophylaxis has varied owing to limited efficacy, reflecting an incomplete understanding of relationships between development of the intestinal microbiome, neonatal dysbiosis and LOS. Using a model of LOS, we found that components of the developing microbiome were both necessary and sufficient to prevent LOS. Maternal antibiotic exposure that eradicated or enriched transmission of Lactobacillus murinus exacerbated and prevented disease, respectively. Prophylactic administration of some, but not all Lactobacillus spp. was protective, as was administration of Escherichia coli. Intestinal oxygen level was a major driver of colonization dynamics, albeit via mechanisms distinct from those in adults. These results establish a link between neonatal dysbiosis and LOS, and provide a basis for rational selection of probiotics that modulate primary succession of the microbiome to prevent disease.
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Affiliation(s)
- Jeffrey R Singer
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Emily G Blosser
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Obstetrics and Gynecology, Ochsner Health System, New Orleans, LA, USA
| | - Carlene L Zindl
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel J Silberger
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sean Conlan
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Vincent A Laufer
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel DiToro
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Clay Deming
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ranjit Kumar
- Center for Clinical and Translational Science Informatics Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Casey D Morrow
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julia A Segre
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Michael J Gray
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David A Randolph
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA.,Division of Neonatal-Perinatal Medicine, Rocky Mountain Hospital for Children, Denver, CO, USA
| | - Casey T Weaver
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Evaluation of in vitro and in vivo antibiotic efficacy against a novel bioluminescent Shigella flexneri. Sci Rep 2019; 9:13567. [PMID: 31537849 PMCID: PMC6753072 DOI: 10.1038/s41598-019-49729-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/30/2019] [Indexed: 12/13/2022] Open
Abstract
Shigella spp., the bacteria responsible for shigellosis, are one of the leading causes of diarrheal morbidity and mortality amongst children. There is a pressing need for the development of novel therapeutics, as resistance of Shigella to many currently used antibiotics is rapidly emerging. This paper describes the development of robust in vitro and in vivo tools to study antibiotic efficacy against Shigella flexneri. A novel bioluminescent S. flexneri strain (S. flexneri lux1) was generated, which can be used in a mammalian epithelial cell co-culture assay to evaluate antibiotic intracellular and extracellular efficacy. In addition, the S. flexneri lux1 strain was used with an intraperitoneal (IP) murine model of shigellosis to test the efficacy of ciprofloxacin and ampicillin. Both antibiotics significantly reduced the observed radiance from the gastrointestinal tissue of infected mice compared to vehicle control. Furthermore, plated gastrointestinal tissue homogenate confirmed antibiotic treatment significantly reduced the S. flexneri infection. However, in contrast to the results generated with tissue homogenate, the radiance data was not able to distinguish between the efficacy of ampicillin and ciprofloxacin. Compared to traditional methods, these models can be utilized for efficient screening of novel antibiotics aiding in the discovery of new treatments against shigellosis.
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Rimet CS, Maurer JJ, Pickler L, Stabler L, Johnson KK, Berghaus RD, Villegas AM, Lee M, França M. Salmonella Harborage Sites in Infected Poultry That May Contribute to Contamination of Ground Meat. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2019. [DOI: 10.3389/fsufs.2019.00002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Zhang Y, Ji W, He L, Chen Y, Ding X, Sun Y, Hu S, Yang H, Huang W, Zhang Y, Liu F, Xia L. E. coli Nissle 1917-Derived Minicells for Targeted Delivery of Chemotherapeutic Drug to Hypoxic Regions for Cancer Therapy. Theranostics 2018; 8:1690-1705. [PMID: 29556350 PMCID: PMC5858176 DOI: 10.7150/thno.21575] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 01/03/2018] [Indexed: 12/18/2022] Open
Abstract
Purpose: Systemic administration of free chemotherapeutic drugs leads to severe toxic effects, and physiological characteristics of solid tumors restrain the drugs from reaching the hypoxic regions. E. coli Nissle 1917 (EcN) has been known to penetrate the barrier and proliferate in the interface between the viable and necrotic regions of tumors. This study aimed to fabricate a nanoscale minicell via genetic engineering of EcN for targeted delivery of chemotherapeutic drugs to the hypoxic regions of tumors for cancer therapy. Methods: A large number of minicells were produced by knocking out the minCD gene and enhancing the minE expression in EcN. Then, a pH (low) insertion peptide (pHLIP) was displayed on the membrane surface through protein display technology to endow the cells with the ability to target the acidic microenvironments of tumors. The acidic-microenvironment targeting ability and therapeutic effect of the engineered minicells with chemotherapeutic drugs was thoroughly evaluated by using breast cancer cells and an orthotopic model of breast tumor. Results: The EcN-derived minicells displaying pHLIP could be directly extracted from the fermentation broth and used for delivering chemotherapeutic drugs without any further modification. Targeting of doxorubicin (DOX)-loaded minicells to cancer cells via pHLIP resulted in rapid internalization and drug release in acidic media. Importantly, the pHLIP-mosaic minicells successfully invaded the necrotic and hypoxic regions of orthotopic breast cancers where free chemotherapeutic drugs could never get to because of vascular insufficiency and high interstitial fluid pressure. This invasion resulted in significant regression of an orthotopic breast tumor in a mouse model, while no seriously pathogenic effects were observed during the animal experiments. Conclusions: This study provides a novel strategy for the fabrication of tumor-targeting carriers via genetic engineering based on biomaterials with the ability to penetrate hypoxic regions of tumors, high biocompatibility and low toxicity.
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Akgul A, Al-Janabi N, Das B, Lawrence M, Karsi A. Small molecules targeting LapB protein prevent Listeria attachment to catfish muscle. PLoS One 2017; 12:e0189809. [PMID: 29253892 PMCID: PMC5734760 DOI: 10.1371/journal.pone.0189809] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 12/01/2017] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenes is a Gram-positive foodborne pathogen and the causative agent of listeriosis. L. monocytogenes lapB gene encodes a cell wall surface anchor protein, and mutation of this gene causes Listeria attenuation in mice. In this work, the potential role of Listeria LapB protein in catfish fillet attachment was investigated. To achieve this, boron-based small molecules designed to interfere with the active site of the L. monocytogenes LapB protein were developed, and their ability to prevent L. monocytogenes attachment to fish fillet was tested. Results indicated that seven out of nine different small molecules were effective in reducing the Listeria attachment to catfish fillets. Of these, three small molecules (SM3, SM5, and SM7) were highly effective in blocking Listeria attachment to catfish fillets. This study suggests an alternative strategy for reduction of L. monocytogenes contamination in fresh and frozen fish products.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Nawar Al-Janabi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Bhaskar Das
- Departments of Medicine and Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Mark Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States of America
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Yeom J, Wayne KJ, Groisman EA. Sequestration from Protease Adaptor Confers Differential Stability to Protease Substrate. Mol Cell 2017; 66:234-246.e5. [PMID: 28431231 DOI: 10.1016/j.molcel.2017.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/23/2017] [Accepted: 03/14/2017] [Indexed: 12/24/2022]
Abstract
According to the N-end rule, the N-terminal residue of a protein determines its stability. In bacteria, the adaptor ClpS mediates proteolysis by delivering substrates bearing specific N-terminal residues to the protease ClpAP. We now report that the Salmonella adaptor ClpS binds to the N terminus of the regulatory protein PhoP, resulting in PhoP degradation by ClpAP. We establish that the PhoP-activated protein MgtC protects PhoP from degradation by outcompeting ClpS for binding to PhoP. MgtC appears to act exclusively on PhoP, as it did not alter the stability of a different ClpS-dependent ClpAP substrate. Removal of five N-terminal residues rendered PhoP stability independent of both the clpS and mgtC genes. By preserving PhoP protein levels, MgtC enables normal temporal transcription of PhoP-activated genes. The identified mechanism provides a simple means to spare specific substrates from an adaptor-dependent protease.
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Affiliation(s)
- Jinki Yeom
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | - Kyle J Wayne
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | - Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA; Yale Microbial Sciences Institute, P.O. Box 27389, West Haven, CT 06516, USA.
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Salmonella enterica Serovar Kentucky Flagella Are Required for Broiler Skin Adhesion and Caco-2 Cell Invasion. Appl Environ Microbiol 2016; 83:AEM.02115-16. [PMID: 27793824 DOI: 10.1128/aem.02115-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/24/2016] [Indexed: 11/20/2022] Open
Abstract
Nontyphoidal Salmonella strains are the main source of pathogenic bacterial contamination in the poultry industry. Recently, Salmonella enterica serovar Kentucky has been recognized as the most prominent serovar on carcasses in poultry-processing plants. Previous studies showed that flagella are one of the main factors that contribute to bacterial attachment to broiler skin. However, the precise role of flagella and the mechanism of attachment are unknown. There are two different flagellar subunits (fliC and fljB) expressed alternatively in Salmonella enterica serovars using phase variation. Here, by making deletions in genes encoding flagellar structural subunits (flgK, fliC, and fljB), and flagellar motor (motA), we were able to differentiate the role of flagella and their rotary motion in the colonization of broiler skin and cellular attachment. Utilizing a broiler skin assay, we demonstrated that the presence of FliC is necessary for attachment to broiler skin. Expression of the alternative flagellar subunit FljB enables Salmonella motility, but this subunit is unable to mediate tight attachment. Deletion of the flgK gene prevents proper flagellar assembly, making Salmonella significantly less adherent to broiler skin than the wild type. S Kentucky with deletions in all three structural genes, fliC, fljB, and flgK, as well as a flagellar motor mutant (motA), exhibited less adhesion and invasion of Caco-2 cells, while an fljB mutant was as adherent and invasive as the wild-type strain. IMPORTANCE In this work, we answered clearly the role of flagella in S Kentucky attachment to the chicken skin and Caco-2 cells. We demonstrated that the presence of FliC is necessary for attachment to broiler skin. Expression of the alternative flagellar subunit FljB enables Salmonella motility, but this subunit is unable to mediate strong attachment. Deletion of the flgK gene prevents proper flagellar assembly, making Salmonella significantly less adherent to broiler skin than the wild type. S Kentucky with deletions in all three structural genes, fliC, fljB, and flgK, as well as a flagellar motor mutant (motA), exhibited less adhesion and invasion of Caco-2 cells, while an fljB mutant was as adherent and invasive as the wild-type strain. We expect these results will contribute to the understanding of the mechanisms of Salmonella attachment to food products.
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Kumar GD, Williams RC, Al Qublan HM, Sriranganathan N, Boyer RR, Eifert JD. Airborne soil particulates as vehicles for Salmonella contamination of tomatoes. Int J Food Microbiol 2016; 243:90-95. [PMID: 28038335 DOI: 10.1016/j.ijfoodmicro.2016.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/22/2016] [Accepted: 12/12/2016] [Indexed: 11/30/2022]
Abstract
The presence of dust is ubiquitous in the produce growing environment and its deposition on edible crops could occur. The potential of wind-distributed soil particulate to serve as a vehicle for S. Newport transfer to tomato blossoms and consequently, to fruits, was explored. Blossoms were challenged with previously autoclaved soil containing S. Newport (9.39log CFU/g) by brushing and airborne transfer. One hundred percent of blossoms brushed with S. Newport-contaminated soil tested positive for presence of the pathogen one week after contact (P<0.0001). Compressed air was used to simulate wind currents and direct soil particulates towards blossoms. Airborne soil particulates resulted in contamination of 29% of the blossoms with S. Newport one week after contact. Biophotonic imaging of blossoms post-contact with bioluminescent S. Newport-contaminated airborne soil particulates revealed transfer of the pathogen on petal, stamen and pedicel structures. Both fruits and calyxes that developed from blossoms contaminated with airborne soil particulates were positive for presence of S. Newport in both fruit (66.6%) and calyx (77.7%). Presence of S. Newport in surface-sterilized fruit and calyx tissue tested indicated internalization of the pathogen. These results show that airborne soil particulates could serve as a vehicle for Salmonella. Hence, Salmonella contaminated dust and soil particulate dispersion could contribute to pathogen contamination of fruit, indicating an omnipresent yet relatively unexplored contamination route.
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Affiliation(s)
- Govindaraj Dev Kumar
- Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Robert C Williams
- Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
| | - Hamzeh M Al Qublan
- Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA
| | - Nammalwar Sriranganathan
- Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA
| | - Renee R Boyer
- Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Joseph D Eifert
- Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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A Modular, Tn7-Based System for Making Bioluminescent or Fluorescent Salmonella and Escherichia coli Strains. Appl Environ Microbiol 2016; 82:4931-43. [PMID: 27260360 DOI: 10.1128/aem.01346-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 05/31/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Our goal was to develop a robust tagging method that can be used to track bacterial strains in vivo To address this challenge, we adapted two existing systems: a modular plasmid-based reporter system (pCS26) that has been used for high-throughput gene expression studies in Salmonella and Escherichia coli and Tn7 transposition. We generated kanamycin- and chloramphenicol-resistant versions of pCS26 with bacterial luciferase, green fluorescent protein (GFP), and mCherry reporters under the control of σ(70)-dependent promoters to provide three different levels of constitutive expression. We improved upon the existing Tn7 system by modifying the delivery vector to accept pCS26 constructs and moving the transposase genes from a nonreplicating helper plasmid into a temperature-sensitive plasmid that can be conditionally maintained. This resulted in a 10- to 30-fold boost in transposase gene expression and transposition efficiencies of 10(-8) to 10(-10) in Salmonella enterica serovar Typhimurium and E. coli APEC O1, whereas the existing Tn7 system yielded no successful transposition events. The new reporter strains displayed reproducible signaling in microwell plate assays, confocal microscopy, and in vivo animal infections. We have combined two flexible and complementary tools that can be used for a multitude of molecular biology applications within the Enterobacteriaceae This system can accommodate new promoter-reporter combinations as they become available and can help to bridge the gap between modern, high-throughput technologies and classical molecular genetics. IMPORTANCE This article describes a flexible and efficient system for tagging bacterial strains. Using our modular plasmid system, a researcher can easily change the reporter type or the promoter driving expression and test the parameters of these new constructs in vitro Selected constructs can then be stably integrated into the chromosomes of desired strains in two simple steps. We demonstrate the use of this system in Salmonella and E. coli, and we predict that it will be widely applicable to other bacterial strains within the Enterobacteriaceae This technology will allow for improved in vivo analysis of bacterial pathogens.
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Salehi S, Howe K, Brooks J, Lawrence ML, Bailey RH, Karsi A. Identification of Salmonella enterica serovar Kentucky genes involved in attachment to chicken skin. BMC Microbiol 2016; 16:168. [PMID: 27473153 PMCID: PMC4966735 DOI: 10.1186/s12866-016-0781-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 07/15/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Regardless of sanitation practices implemented to reduce Salmonella prevalence in poultry processing plants, the problem continues to be an issue. To gain an understanding of the attachment mechanism of Salmonella to broiler skin, a bioluminescent-based mutant screening assay was used. A random mutant library of a field-isolated bioluminescent strain of Salmonella enterica serovar Kentucky was constructed. Mutants' attachment to chicken skin was assessed in 96-well plates containing uniform 6 mm diameter pieces of circular chicken skin. After washing steps, mutants with reduced attachment were selected based on reduced bioluminescence, and transposon insertion sites were identified. RESULTS Attachment attenuation was detected in transposon mutants with insertion in genes encoding flagella biosynthesis, lipopolysaccharide core biosynthesis protein, tryptophan biosynthesis, amino acid catabolism pathway, shikimate pathway, tricarboxylic acid (TCA) cycle, conjugative transfer system, multidrug resistant protein, and ATP-binding cassette (ABC) transporter system. In particular, mutations in S. Kentucky flagellar biosynthesis genes (flgA, flgC, flgK, flhB, and flgJ) led to the poorest attachment of the bacterium to skin. CONCLUSIONS The current study indicates that attachment of Salmonella to broiler skin is a multifactorial process, in which flagella play an important role.
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Affiliation(s)
- Sanaz Salehi
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Kevin Howe
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - John Brooks
- USDA-ARS, Genetics and Precision Agriculture Unit, Mississippi State, Mississippi, USA
| | - Mark L. Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - R. Hartford Bailey
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
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Oosterik LH, Tuntufye HN, Tsonos J, Luyten T, Noppen S, Liekens S, Lavigne R, Butaye P, Goddeeris BM. Bioluminescent avian pathogenic Escherichia coli for monitoring colibacillosis in experimentally infected chickens. Vet J 2016; 216:87-92. [PMID: 27687932 DOI: 10.1016/j.tvjl.2016.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 07/17/2016] [Accepted: 07/18/2016] [Indexed: 11/30/2022]
Abstract
Avian pathogenic Escherichia coli (APEC) are responsible for significant economic losses in the poultry industry. In this study, a model for investigating the pathogenesis of APEC infections was established. APEC strain CH2 (O78) was marked with the luciferase operon (luxCDABE) using a Tn7 transposon and tissues of experimentally infected chickens were analysed for a correlation between the bioluminescent signal and the number of bacteria. Transposition of the lux operon into the chromosome of the APEC isolate did not affect sensitivity to lytic bacteriophages and there was no effect on virulence in an intratracheal infection model in 1-day-old chicks, although results with a subcutaneous infection model were inconclusive. A correlation between the number of bacteria and the luminescent signal was found in liquid medium, as well as in homogenised heart, liver, spleen and lung of 4-week-old experimentally infected chickens. This study showed that lux could be used for identification of the infecting strain after experimental infection with APEC in poultry.
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Affiliation(s)
- Leon H Oosterik
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium; Department of General Bacteriology, Centrum voor Onderzoek in Diergeneeskunde en Agrochemie-Centre d'Etude et de Recherches Vétérinaires et Agrochimiques (CODA-CERVA), Groeselenberg 99, Brussels 1180, Belgium.
| | - Huruma N Tuntufye
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium
| | - Jessica Tsonos
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium; Structural and Molecular Microbiology, Structural Biology Research Center, Vlaams Instituut voor Biotechnologie (VIB), Vrije Universiteit Brussel, Pleinlaan 2, Brussels 1050, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, Brussels 1050, Belgium
| | - Tom Luyten
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium
| | - Sam Noppen
- Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Katholieke Universiteit Leuven, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Sandra Liekens
- Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Katholieke Universiteit Leuven, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Rob Lavigne
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium
| | - Patrick Butaye
- Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke 9820, Belgium
| | - Bruno M Goddeeris
- Department of Biosystems, Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven 3000, Belgium
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Diagnosis of cancer multidrug resistance by bacterium-mediated imaging. Med Hypotheses 2016; 89:11-5. [DOI: 10.1016/j.mehy.2016.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 10/07/2015] [Accepted: 01/26/2016] [Indexed: 12/17/2022]
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Liu Z, Que F, Liao L, Zhou M, You L, Zhao Q, Li Y, Niu H, Wu S, Huang R. Study on the promotion of bacterial biofilm formation by a Salmonella conjugative plasmid and the underlying mechanism. PLoS One 2014; 9:e109808. [PMID: 25299072 PMCID: PMC4192535 DOI: 10.1371/journal.pone.0109808] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 09/12/2014] [Indexed: 12/12/2022] Open
Abstract
To investigate the effect of the pRST98 plasmid, originally isolated from Salmonella enterica serovar Typhi (S. Typhi), on biofilm (BF) formation, we carried out in vitro experiments using S. Typhi, Salmonella enterica serovar Typhimurium (S. Typhimurium) and Escherichia coli (E. coli). We further explored the effects of pRST98 in vivo by establishing two animal models, a tumor-bearing mouse model and a mouse urethral catheter model. Moreover, we examined the relationship between the quorum-sensing (QS) system and pRST98-mediated BF formation. These studies showed that pRST98 enhanced BF formation in different bacteria in vitro. In both animal models, pRST98 promoted BF formation and caused more severe pathological changes. It was previously reported that Salmonella senses exogenous N-acylhomoserine lactones (AHLs) through the regulatory protein SdiA and regulates the expression of genes including the virulence gene rck, which is located on the virulence plasmid of some serotypes of Salmonella. In this study, we confirmed the locus of the rck gene on pRST98 and found that AHLs increased rck expression in pRST98-carrying strains, thereby enhancing bacterial adherence, serum resistance and bacterial BF formation. In conclusion, the Salmonella conjugative plasmid pRST98 promotes bacterial BF formation both in vitro and in vivo, and the mechanism may relate to the AHL-SdiA-Rck signaling pathway.
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Affiliation(s)
- Zhen Liu
- Medical College of Soochow University, Suzhou, P. R. China
| | - Fengxia Que
- Medical College of Soochow University, Suzhou, P. R. China
| | - Li Liao
- Medical College of Soochow University, Suzhou, P. R. China
| | - Min Zhou
- Medical College of Soochow University, Suzhou, P. R. China
| | - Lixiang You
- Medical College of Soochow University, Suzhou, P. R. China
| | - Qing Zhao
- Medical College of Soochow University, Suzhou, P. R. China
| | - Yuanyuan Li
- Medical College of Soochow University, Suzhou, P. R. China
| | - Hua Niu
- Medical College of Soochow University, Suzhou, P. R. China
| | - Shuyan Wu
- Medical College of Soochow University, Suzhou, P. R. China
| | - Rui Huang
- Medical College of Soochow University, Suzhou, P. R. China
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A Salmonella enterica conjugative plasmid impairs autophagic flux in infected macrophages. Microbes Infect 2014; 16:553-61. [PMID: 24857879 DOI: 10.1016/j.micinf.2014.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 05/07/2014] [Accepted: 05/07/2014] [Indexed: 11/24/2022]
Abstract
pR(ST98) was originally isolated from Salmonella enterica serovar typhi and could be transferred among enteric bacilli by conjugation. Our previous studies indicated that it could intervene in autophagy of host cells, while the mechanism remained undefined. Here, we explored how pR(ST98) influenced the autophagic flux of murine macrophage-like cell line (J774A.1). S. enterica serovar typhimurium wild type strain (χ3306), harboring a 100 kb virulence plasmid, was used as a positive control. pR(ST98) was transferred into χ3306 virulence plasmid cured strain (χ3337) to create the transconjugant strain (χ3337/pR(ST98)). The bacterial strains incubated with J774A.1 revealed that survival rate of intracellular bacteria carrying pR(ST98) was higher than that of plasmid free strain; presence of pR(ST98) decreased the number of autophagy vacuoles, LC3 positive and p62 positive bacteria, and also the level of LC3-II and degradation of p62 in macrophages. After intervention with autophagy inhibitor chloroquine, the amount of LC3-II and autophagy vacuoles were still lower in macrophages infected with strains carrying pR(ST98). Our study suggested that pR(ST98) could block or delay the formation of autophagosome in the earlier autophagy process, but couldn't affect the function of autolysosome. This finding provided novel insights into the role of enteric conjugation plasmid in bacterial pathogenesis.
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Shining light on food microbiology; applications of Lux-tagged microorganisms in the food industry. Trends Food Sci Technol 2013. [DOI: 10.1016/j.tifs.2013.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Monteiro F, Genin S, van Dijk I, Valls M. A luminescent reporter evidences active expression of Ralstonia solanacearum type III secretion system genes throughout plant infection. MICROBIOLOGY-SGM 2012; 158:2107-2116. [PMID: 22609750 DOI: 10.1099/mic.0.058610-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although much is known about the signals that trigger transcription of virulence genes in plant pathogens, their prevalence and timing during infection are still unknown. In this work, we address these questions by analysing expression of the main pathogenicity determinants in the bacterial pathogen Ralstonia solanacearum. We set up a quantitative, non-invasive luminescent reporter to monitor in planta transcription from single promoters in the bacterial chromosome. We show that the new reporter provides a real-time measure of promoter output in vivo - either after re-isolation of pathogens from infected plants or directly in situ - and confirm that the promoter controlling exopolysaccharide (EPS) synthesis is active in bacteria growing in the xylem. We also provide evidence that hrpB, the master regulator of type III secretion system (T3SS) genes, is transcribed in symptomatic plants. Quantitative RT-PCR assays demonstrate that hrpB and type III effector transcripts are abundant at late stages of plant infection, suggesting that their function is required throughout disease. Our results challenge the widespread view in R. solanacearum pathogenicity that the T3SS, and thus injection of effector proteins, is only active to manipulate plant defences at the first stages of infection, and that its expression is turned down when bacteria reach high cell densities and EPS synthesis starts.
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Affiliation(s)
- Freddy Monteiro
- Department Genètica, Universitat de Barcelona and Centre de Recerca Agrigenòmica (IRTA-CSIC-UAB-UB) Edifici CRAG, Campus UAB, 08193 Bellaterra, Catalonia, Spain
| | - Stéphane Genin
- INRA, CNRS - Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR 441/2594, 31326 Castanet Tolosan, France
| | - Irene van Dijk
- Department Genètica, Universitat de Barcelona and Centre de Recerca Agrigenòmica (IRTA-CSIC-UAB-UB) Edifici CRAG, Campus UAB, 08193 Bellaterra, Catalonia, Spain
| | - Marc Valls
- Department Genètica, Universitat de Barcelona and Centre de Recerca Agrigenòmica (IRTA-CSIC-UAB-UB) Edifici CRAG, Campus UAB, 08193 Bellaterra, Catalonia, Spain
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Sitaras C, Beyde A, Malekazari P, Herrington MB. Light producing reporter plasmids for Escherichia coli K-12 that can be integrated into the chromosome. Plasmid 2011; 65:232-8. [PMID: 21376749 DOI: 10.1016/j.plasmid.2011.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 10/18/2022]
Abstract
Plasmid vectors using the Photorhabdus luminescenslux operon can be used for real time measurements of promoter activity. We have generated a series of lux vectors that have a conditional origin of replication, different selectable markers and the attP sequence from λ. Single copies of these plasmids can be integrated into the λ attachment site in the Escherichia coli chromosome. We constructed reporter derivatives and compared light production when the plasmids were present in multiple copies and in single copies. We also demonstrated that expression could be induced under the appropriate conditions.
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Affiliation(s)
- Chris Sitaras
- Biology Department, Concordia University, Montreal, QC H4B1R6, Canada
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