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Sain A, Sharma DK, Singathia R, Gaurav A, Patidar C, Suthar P, Rathore K, Juneja R. Antibiotic resistance and virulence genes profile of Non typhodial Salmonella species isolated from poultry enteritis in India. Trop Anim Health Prod 2024; 56:91. [PMID: 38430331 DOI: 10.1007/s11250-024-03932-0] [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: 02/21/2023] [Accepted: 02/15/2024] [Indexed: 03/03/2024]
Abstract
Salmonella species (spp) is the most important gastrointestinal pathogen present ubiquitously. Non typhoidal Salmonella (NTS) is commonly associated with gastroenteritis in humans. Layer birds once get infection with NTS, can become persistently infected with Salmonella Typhimurium and intermittently shed the bacteria. It results in a high risk of potential exposure of eggs to the bacteria. The current study was conducted to determine the serotype diversity, presence of virulence genes, antibiotic resistance pattern, and genes of NTS from poultry enteritis. Out of 151 intestinal swabs from poultry total 118 NTS were isolated, which were characterized serologically as S. Typhimurium (51 strains), S. Weltevreden (57 strains) and untypable (10 strains). Most effective antibiotics were amikacin, gentamycin and ceftriaxone (33.05%) followed by ampicillin, azithromycin and ciprofloxacin (16.69%), co-trimoxazole (13.55%), and tetracycline (6.78%). Multidrug resistance recorded in 17.70% (N = 21/118) strains. Antimicrobial-resistant genes i.e. blaTEM, blaSHV, blaCTX-M, tet(A), tet(B), tet(C), sul1, sul2, sul3. blaTEM and tet(A) were present in 95% (20/21). Eleven virulence genes i.e. invA, hilA, sivH, tolC, agfA, lpfA, spaN, pagC, spiA, iroN and fliC 2 were present in all the 30 isolates. While, sopE was present in only 2 isolates, NTS strains with characteristics of pathogenicity and multidrug resistance from poultry enteritis were detected. Multidrug resistance showed the necessity of prudent use of antibiotics in the poultry industry.
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Affiliation(s)
- Arpita Sain
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | | | - Rajesh Singathia
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | - Abhishek Gaurav
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | - Chaman Patidar
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | - PrabuRam Suthar
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | - Karishma Rathore
- Department of Veterinary Public Health and Epidemiology, College of Veterinary and Animal Science (CVAS), Navania, India
| | - Rohit Juneja
- Department of Veterinary Gynaecology and Obstetrics, CVAS, Navania, India
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2
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Sandrasaigaran P, Mohan S, Segaran NS, Lee TY, Radu S, Hasan H. Prevalence of multi-antimicrobial resistant non-typhoidal Salmonella isolated from filth flies at wet markets in Klang, Malaysia, and their survival in the simulated gastric fluid. Int J Food Microbiol 2023; 407:110390. [PMID: 37722349 DOI: 10.1016/j.ijfoodmicro.2023.110390] [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: 04/13/2023] [Revised: 08/30/2023] [Accepted: 09/02/2023] [Indexed: 09/20/2023]
Abstract
Filth flies at wet markets can be a vector harbouring multiple antimicrobial-resistant (MAR) nontyphoidal Salmonella (NTS), and such strains are a significant threat to public health as they may cause severe infections in humans. This study aims to investigate the prevalence of antimicrobial-resistant NTS, especially Salmonella Enteritidis and S. Typhimurium harboured by filth flies at wet markets, and investigate their survival in the simulated gastric fluid (SGF). Filth flies (n = 90) were captured from wet markets in Klang, Malaysia, and processed to isolate Salmonella spp. The isolates (n = 16) were identified using the multiplex-touchdown PCR and assessed their antimicrobial susceptibility against 11 antimicrobial agents. Finally, three isolates with the highest MAR index were subjected to SGF survival tests. It was observed that 17.8 % of flies (n = 16/90) harbouring Salmonella, out of which 10 % (n = 9/90) was S. Enteritidis, 2.2 % (n = 2/90) was S. Typhimurium, and 5.6 % was unidentified serotypes of Salmonella enterica subsp. I. 43.8 % (n = 7/16) were confirmed as MAR, and they were observed to be resistant against ampicillin, chloramphenicol, kanamycin, streptomycin, and nalidixic acid. Three strains, F35, F75, and F85 demonstrated the highest MAR index and were able to survive (>6-log10) in the SGF (180 min), indicating their potential virulence and invasiveness. This study provides significant insights into the prevalence and severity of MAR nontyphoidal Salmonella harboured by filth flies in wet markets, which may help inform strategies for controlling the spread and outbreak of foodborne disease.
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Affiliation(s)
- Pratheep Sandrasaigaran
- Department of Biotechnology, School of Biotechnology, Manipal International University, Nilai, Negeri Sembilan, Malaysia; Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Shuvarnah Mohan
- Department of Biotechnology, School of Biotechnology, Manipal International University, Nilai, Negeri Sembilan, Malaysia
| | - Nithiyha Sandara Segaran
- Department of Biotechnology, School of Biotechnology, Manipal International University, Nilai, Negeri Sembilan, Malaysia
| | - Tze Yan Lee
- School of Liberal Arts, Science and Technology (PUScLST), Perdana University, Wisma Chase Perdana, Changkat Semantan Damansara Heights, 50490 Kuala Lumpur, Malaysia
| | - Son Radu
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Hanan Hasan
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia; Halal Products Research Institute, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
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3
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Esteves NC, Bigham DN, Scharf BE. Phages on filaments: A genetic screen elucidates the complex interactions between Salmonella enterica flagellin and bacteriophage Chi. PLoS Pathog 2023; 19:e1011537. [PMID: 37535496 PMCID: PMC10399903 DOI: 10.1371/journal.ppat.1011537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
The bacterial flagellum is a rotary motor organelle and important virulence factor that propels motile pathogenic bacteria, such as Salmonella enterica, through their surroundings. Bacteriophages, or phages, are viruses that solely infect bacteria. As such, phages have myriad applications in the healthcare field, including phage therapy against antibiotic-resistant bacterial pathogens. Bacteriophage χ (Chi) is a flagellum-dependent (flagellotropic) bacteriophage, which begins its infection cycle by attaching its long tail fiber to the S. enterica flagellar filament as its primary receptor. The interactions between phage and flagellum are poorly understood, as are the reasons that χ only kills certain Salmonella serotypes while others entirely evade phage infection. In this study, we used molecular cloning, targeted mutagenesis, heterologous flagellin expression, and phage-host interaction assays to determine which domains within the flagellar filament protein flagellin mediate this complex interaction. We identified the antigenic N- and C-terminal D2 domains as essential for phage χ binding, with the hypervariable central D3 domain playing a less crucial role. Here, we report that the primary structure of the Salmonella flagellin D2 domains is the major determinant of χ adhesion. The phage susceptibility of a strain is directly tied to these domains. We additionally uncovered important information about flagellar function. The central and most variable domain, D3, is not required for motility in S. Typhimurium 14028s, as it can be deleted or its sequence composition can be significantly altered with minimal impacts on motility. Further knowledge about the complex interactions between flagellotropic phage χ and its primary bacterial receptor may allow genetic engineering of its host range for use as targeted antimicrobial therapy against motile pathogens of the χ-host genera Salmonella, Escherichia, or Serratia.
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Affiliation(s)
- Nathaniel C. Esteves
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Danielle N. Bigham
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Birgit E. Scharf
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
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Jafari Najaf Abadi MH, Abyaneh FA, Zare N, Zamani J, Abdoli A, Aslanbeigi F, Hamblin MR, Tarrahimofrad H, Rahimi M, Hashemian SM, Mirzaei H. In silico design and immunoinformatics analysis of a chimeric vaccine construct based on Salmonella pathogenesis factors. Microb Pathog 2023; 180:106130. [PMID: 37121524 DOI: 10.1016/j.micpath.2023.106130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/02/2023]
Abstract
Currently, there are two vaccines based on killed and/or weakened Salmonella bacteria, but no recombinant vaccine is available for preventing or treating the disease. We used an in silico approach to design a multi-epitope vaccine against Salmonella using OmpA, OmpS, SopB, SseB, SthA and FilC antigens. We predicted helper T lymphocyte, cytotoxic T lymphocyte, and IFN-γ epitopes. The FilC sequence was used as a bovine TLR5 agonist, and the linkers KK, AAY, GPGPG and EAAAK were used to connect epitopes. The final sequence consisted of 747 amino acid residues, and the expressed soluble protein (∼79.6 kDa) was predicted to be both non-allergenic and antigenic. The tertiary structure of modeled protein was refined and validated, and the interactions of vaccine 3D structure were evaluated using molecular docking, and molecular dynamics simulation (RMSD, RMSF and Gyration). This structurally stable protein could interact with human TLR5. The C-ImmSim server predicted that this proposed vaccine likely induces an immune response by stimulating T and B cells, making it a potential candidate for further evaluation for the prevention and treatment of Salmonella infection.
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Affiliation(s)
| | | | - Noushid Zare
- Faculty of Pharmacy, International Campus, Tehran University of Medical Science, Tehran, Iran
| | - Javad Zamani
- Department of Animal Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Amirhossein Abdoli
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Fatemeh Aslanbeigi
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Michael R Hamblin
- Laser Research Centre, Faculty of Health Science, University of Johannesburg, Doornfontein, 2028, South Africa
| | - Hossein Tarrahimofrad
- Department of Animal Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
| | - Mohammadreza Rahimi
- Infectious Diseases Research Center, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
| | - Seyed Mohammadreza Hashemian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Disease, Shahid Beheshti University of Medical Sciences, Tehran, 1983535511, Iran.
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
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Identification and Characterization of the Alternative σ 28 Factor in Treponema denticola. J Bacteriol 2022; 204:e0024822. [PMID: 36043861 PMCID: PMC9487585 DOI: 10.1128/jb.00248-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
FliA (also known as σ28), a member of the bacterial σ70 family of transcription factors, directs RNA polymerase to flagellar late (class 3) promoters and initiates transcription. FliA has been studied in several bacteria, yet its role in spirochetes has not been established. In this report, we identify and functionally characterize a FliA homolog (TDE2683) in the oral spirochete Treponema denticola. Computational, genetic, and biochemical analyses demonstrated that TDE2683 has a structure similar to that of the σ28 of Escherichia coli, binds to σ28-dependent promoters, and can functionally replace the σ28 of E. coli. However, unlike its counterparts from other bacteria, TDE2683 cannot be deleted, suggesting its essential role in the survival of T. denticola. In vitro site-directed mutagenesis revealed that E221 and V231, two conserved residues in the σ4 region of σ28, are indispensable for the binding activity of TDE2683 to the σ28-dependent promoter. We then mutated these two residues in T. denticola and found that the mutations impair the expression of flagellin and chemotaxis genes and bacterial motility as well. Cryo-electron tomography analysis further revealed that the mutations disrupt the flagellar symmetry (i.e., number and placement) of T. denticola. Collectively, these results indicate that TDE2683 is a σ28 transcription factor that regulates the class 3 gene expression and controls the flagellar symmetry of T. denticola. To the best of our knowledge, this is the first report establishing the functionality of FliA in spirochetes. IMPORTANCE Spirochetes are a group of medically important but understudied bacteria. One of the unique aspects of spirochetes is that they have periplasmic flagella (PF, also known as endoflagella) which give rise to their unique spiral shape and distinct swimming behaviors and play a critical role in the pathophysiology of spirochetes. PF are structurally similar to external flagella, but the underpinning mechanism that regulates PF biosynthesis and assembly remains largely unknown. By using the oral spirochete Treponema denticola as a model, this report provides several lines of evidence that FliA, a σ28 transcriptional factor, regulates the late flagellin gene (class 3) expression, PF assembly, and flagellar symmetry as well, which provides insights into flagellar regulation and opens an avenue to investigate the role of σ28 in spirochetes.
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Niu L, Zhang Y, Jie M, Cheng Y, Xiang Q, Zhang Z, Bai Y. Synergetic effect of
petit
‐high pressure carbon dioxide combined with cinnamon (
Cinnamomum cassia
) essential oil against
Salmonella typhimurium. Int J Food Sci Technol 2022. [DOI: 10.1111/ijfs.15613] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Liyuan Niu
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control Zhengzhou China
- Collaborative Innovation Center of Food Production and Safety Henan Province Zhengzhou China
| | - Yilin Zhang
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
| | - Mingsha Jie
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control Zhengzhou China
- Collaborative Innovation Center of Food Production and Safety Henan Province Zhengzhou China
| | - Yingxin Cheng
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
| | - Qisen Xiang
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control Zhengzhou China
- Collaborative Innovation Center of Food Production and Safety Henan Province Zhengzhou China
| | - Zhijian Zhang
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control Zhengzhou China
- Collaborative Innovation Center of Food Production and Safety Henan Province Zhengzhou China
| | - Yanhong Bai
- College of Food and Bioengineering Zhengzhou University of Light Industry Zhengzhou China
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control Zhengzhou China
- Collaborative Innovation Center of Food Production and Safety Henan Province Zhengzhou China
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Abstract
The FliE component of the bacterial flagellum is the first protein secreted through the flagellar type III secretion system (fT3SS) that is capable of self-assembly into the growing bacterial organelle. The FliE protein plays dual roles in the assembly of the Salmonella flagellum as the final component of the flagellar type III secretion system (fT3SS) and as an adaptor protein that anchors the rod (drive shaft) of the flagellar motor to the membrane-imbedded MS-ring structure. This work has identified the interactions between FliE and other proteins at the inner membrane base of the flagellar machine. The fliE sequence coding for the 104-amino-acid protein was subject to saturating mutagenesis. Single-amino-acid substitutions were generated in fliE, resulting in motility phenotypes. From these mutants, intergenic suppressor mutations were generated, isolated, and characterized. Single-amino-acid mutations defective in FliE function were localized to the N- and C-terminal helices of the protein. Motile suppressors of amino acid mutations in fliE were found in rod protein genes flgB and flgC, the MS ring gene, fliF, and one of the core T3SS genes, fliR. These results support the hypothesis that FliE acts as a linker protein consisting of an N-terminal α-helix that is involved in the interaction with the MS ring with a rotational symmetry and a C-terminal coiled coil that interacts with FliF, FliR, FlgB, and FlgC, and these interactions open the exit gate of the protein export channel of the fT3SS.
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Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure. Int J Mol Sci 2021; 22:ijms22147521. [PMID: 34299141 PMCID: PMC8306008 DOI: 10.3390/ijms22147521] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.
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Sevrin G, Massier S, Chassaing B, Agus A, Delmas J, Denizot J, Billard E, Barnich N. Adaptation of adherent-invasive E. coli to gut environment: Impact on flagellum expression and bacterial colonization ability. Gut Microbes 2020; 11:364-380. [PMID: 29494278 PMCID: PMC7524368 DOI: 10.1080/19490976.2017.1421886] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The pathogenesis of Crohn's disease (CD) is multifactorial and involves genetic susceptibility, environmental triggers and intestinal microbiota. Adherent-invasive Escherichia coli (AIEC) are flagellated bacteria more prevalent in CD patients than in healthy subjects and promote chronic intestinal inflammation. We aim at deciphering the role of flagella and flagellin modulation by intestinal conditions. AIEC flagellum expression is required for optimal adhesion to and invasion of intestinal epithelial cells. Interestingly, differential flagellin regulation was observed between commensal E. coli (HS) and AIEC (LF82) strains: flagellum expression by AIEC bacteria, in contrast to that of commensal E. coli, is enhanced under intestinal conditions (the presence of bile acids and mucins). Flagella are involved in the ability of the AIEC LF82 strain to cross a mucus layer in vitro and in vivo, conferring a selective advantage in penetrating the mucus layer and reaching the epithelial surface. In a CEABAC10 mouse model, a non-motile mutant (LF82-ΔfliC) exhibits reduced colonization that is restored by a dextran sodium sulfate treatment that alters mucus layer integrity. Moreover, a mutant that continuously secretes flagellin (LF82-ΔflgM) triggers a stronger inflammatory response than the wild-type strain, and the mutant's ability to colonize the CEABAC10 mouse model is decreased. Overexpression of flagellin in bacteria in contact with epithelial cells can be detrimental to their virulence by inducing acute inflammation that enhances AIEC clearance. AIEC pathobionts must finely modulate flagellum expression during the infection process, taking advantage of their specific virulence gene regulation to improve their adaptability and flexibility within the gut environment.
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Affiliation(s)
- Gwladys Sevrin
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France
| | - Sébastien Massier
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France
| | - Benoit Chassaing
- Neuroscience Institute & Institute for Biomedical Sciences, Georgia State University, Atlanta, USA
| | - Allison Agus
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France
| | - Julien Delmas
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France,Service de Bactériologie, Parasitologie Mycologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Jérémy Denizot
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France,Université Clermont Auvergne, Institut Universitaire de Technologie de Clermont-Ferrand, Clermont-Ferrand, France
| | - Elisabeth Billard
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France,Université Clermont Auvergne, Institut Universitaire de Technologie de Clermont-Ferrand, Clermont-Ferrand, France
| | - Nicolas Barnich
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000Clermont-Ferrand, France,Université Clermont Auvergne, Institut Universitaire de Technologie de Clermont-Ferrand, Clermont-Ferrand, France,CONTACT Nicolas Barnich M2iSH, Inserm, Université Clermont Auvergne, USC-INRA 2018, 28 place Henri Dunant, 63001Clermont-Ferrand, France
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Effectiveness of BOX-PCR in Differentiating Genetic Relatedness among Salmonella enterica Serotype 4,[5],12:i:- Isolates from Hospitalized Patients and Minced Pork Samples in Northern Thailand. Int J Microbiol 2019; 2019:5086240. [PMID: 31316564 PMCID: PMC6604291 DOI: 10.1155/2019/5086240] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/18/2019] [Indexed: 11/25/2022] Open
Abstract
Salmonella enterica Serotype 4,[5],12:i:-, a monophasic variant of S. Typhimurium, with high virulence and multidrug resistance is distributed globally causing pathogenicity to both humans and domesticated animals. BOX-A1R-based repetitive extragenic palindromic-PCR (BOX)-PCR proved to be superior to three other repetitive element-based PCR typing methods, namely, enterobacterial repetitive intergenic consensus (ERIC)-, poly-trinucleotide (GTG)5-, and repetitive extragenic palindromic (REP)-PCR (carried out under a single optimized amplification condition), in differentiating genetic relatedness among S. 4,[5],12:i:- isolates from feces of hospitalized patients (n=12) and isolates from minced pork samples of S. 4,[5],12:i:- (n=6), S. Typhimurium (n=6), and Salmonella Serogroup B (n=4) collected from different regions of northern Thailand. Construction of phylogenetic trees from amplicon size patterns allowed allocation of Salmonella isolates into clusters of similar genetic relatedness, with BOX-PCR generating more unique clusters for each serotype than the other three typing methods. BOX-, (GTG)5-, and REP-PCR indicated significant genetic relatedness between S. 4,[5],12:i:- isolates 1 and 9 from hospitalized patients and S. 4,[5],12:i:- isolate en 29 from minced pork, suggesting a possible route of transmission. Thus, BOX-PCR provides a suitable molecular typing method for discriminating genetic relatedness among Salmonella spp. of the same and different serotypes and should be suitable for application in typing and tracking route of transmission in Salmonella outbreaks.
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11
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Green CA, Kamble NS, Court EK, Bryant OJ, Hicks MG, Lennon C, Fraser GM, Wright PC, Stafford GP. Engineering the flagellar type III secretion system: improving capacity for secretion of recombinant protein. Microb Cell Fact 2019; 18:10. [PMID: 30657054 PMCID: PMC6337784 DOI: 10.1186/s12934-019-1058-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/08/2019] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND Many valuable biopharmaceutical and biotechnological proteins have been produced in Escherichia coli, however these proteins are almost exclusively localised in the cytoplasm or periplasm. This presents challenges for purification, i.e. the removal of contaminating cellular constituents. One solution is secretion directly into the surrounding media, which we achieved via the 'hijack' of the flagellar type III secretion system (FT3SS). Ordinarily flagellar subunits are exported through the centre of the growing flagellum, before assembly at the tip. However, we exploit the fact that in the absence of certain flagellar components (e.g. cap proteins), monomeric flagellar proteins are secreted into the supernatant. RESULTS We report the creation and iterative improvement of an E. coli strain, by means of a modified FT3SS and a modular plasmid system, for secretion of exemplar proteins. We show that removal of the flagellin and HAP proteins (FliC and FlgKL) resulted in an optimal prototype. We next developed a high-throughput enzymatic secretion assay based on cutinase. This indicated that removal of the flagellar motor proteins, motAB (to reduce metabolic burden) and protein degradation machinery, clpX (to boost FT3SS levels intracellularly), result in high capacity secretion. We also show that a secretion construct comprising the 5'UTR and first 47 amino acidsof FliC from E. coli (but no 3'UTR) achieved the highest levels of secretion. Upon combination, we show a 24-fold improvement in secretion of a heterologous (cutinase) enzyme over the original strain. This improved strain could export a range of pharmaceutically relevant heterologous proteins [hGH, TrxA, ScFv (CH2)], achieving secreted yields of up to 0.29 mg L-1, in low cell density culture. CONCLUSIONS We have engineered an E. coli which secretes a range of recombinant proteins, through the FT3SS, to the extracellular media. With further developments, including cell culture process strategies, we envision further improvement to the secreted titre of recombinant protein, with the potential application for protein production for biotechnological purposes.
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Affiliation(s)
- Charlotte A Green
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK.,Sustainable Process Technologies, Chemical and Environmental Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Nitin S Kamble
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - Elizabeth K Court
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - Owain J Bryant
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Matthew G Hicks
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - Christopher Lennon
- FUJIFILM Diosynth Biotechnologies, Belasis Avenue, Stockton-on-Tees, Billingham, TS23 1LH, UK
| | - Gillian M Fraser
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Phillip C Wright
- School of Engineering, The Faculty of Science, Agriculture and Engineering, Newcastle University, Newcastle, NE1 7RU, UK
| | - Graham P Stafford
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK.
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12
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Draft Genome Sequences of Three Salmonella enterica Serovar 4,[5],12:i:- Strains and One S. enterica Serovar Typhimurium Strain, Isolated in Brazil. GENOME ANNOUNCEMENTS 2018; 6:6/27/e00488-18. [PMID: 29976603 PMCID: PMC6033978 DOI: 10.1128/genomea.00488-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Draft genomes of three Salmonella enterica 4,[5],12:i:− (STi) strains isolated from human infections were obtained using Illumina sequencing. They were negative for the fljBA operon but positive for hin, and k-mer analyses revealed their identity as S. enterica 4,[5],12:i:− 08-1736 and S. Draft genomes of three Salmonella enterica 4,[5],12:i:− (STi) strains isolated from human infections were obtained using Illumina sequencing. They were negative for the fljBA operon but positive for hin, and k-mer analyses revealed their identity as S. enterica 4,[5],12:i:− 08-1736 and S. Typhimurium. A draft S. Typhimurium sequence is described for comparison.
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13
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Osterman IA, Dikhtyar YY, Bogdanov AA, Dontsova OA, Sergiev PV. Regulation of Flagellar Gene Expression in Bacteria. BIOCHEMISTRY (MOSCOW) 2016; 80:1447-56. [PMID: 26615435 DOI: 10.1134/s000629791511005x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The flagellum of a bacterium is a supramolecular structure of extreme complexity comprising simultaneously both a unique system of protein transport and a molecular machine that enables the bacterial cell movement. The cascade of expression of genes encoding flagellar components is closely coordinated with the steps of molecular machine assembly, constituting an amazing regulatory system. Data on structure, assembly, and regulation of flagellar gene expression are summarized in this review. The regulatory mechanisms and correlation of the process of regulation of gene expression and flagellum assembly known from the literature are described.
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Affiliation(s)
- I A Osterman
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.
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14
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Hashmi MZ, Qin Z, Yao X, Ahmed Z, Xiaomei S, Shen C, Tang X. PCBs attenuation and abundance of Dehalococcoides spp., bphC, CheA, and flic genes in typical polychlorinated biphenyl-polluted soil under floody and dry soil conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3907-3913. [PMID: 26503002 DOI: 10.1007/s11356-015-5577-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
This study investigates PCBs attenuation and the abundance of active polychlorinated-degrading Dehalococcoides spp. biphenyl dioxygenase (bphC), chemotaxis (CheA), and flagellum (flic) genes in floody and dry soil conditions polluted with polychlorinated biphenyls. The results revealed that total PCBs, high chlorinated PCBs (>4 cl), and less chlorinated PCBs (<4 cl) decreased with the passage of time in floody and dry soil conditions. The reduction of total PCBs (13.87%) and less chlorinated PCBs (15.39%) was more in dry soil than floody soil, while high chlorinated PCBs showed more reduction in floody soil (8.06%) than dry soil. Dehaloccoides spp., bphC, CheA, and flic genes indicated temporal dynamics in abundance in floody and dry soil conditions. The highest abundance was 1.6 × 10(9), 3.7 × 10(4), and 3.6 × 10(2) copies in floody and 1.6 × 10(4) copies in dry soil for Dehalococcoides spp., bphC, CheA, and flic, respectively. Multivariate statistics (RDA) revealed that Dehaloccoides spp. were positively influenced by the higher chlorinated PCBs and soil physical properties, CheA gene with floody soil, flic gene with total PCBs and less chlorinated PCBs, and bphC gene was affected with moisture contents and less chlorinated PCBs. This study provides new insight in the attenuation of PCBs and the abundance of active Dehalococcoides spp. and genes in PCBs polluted soil under floody and dry soil conditions.
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Affiliation(s)
- Muhammad Zaffar Hashmi
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
- Department of Meteorology, COMSATS Institute of Information Technology, Park road, Islamabad, Pakistan
- Institute of Health and Management Sciences, Green Avenue, Park Road, Islamabad, Pakistan
| | - Zhihui Qin
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Xiaoyan Yao
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Zulkifl Ahmed
- Department of Building and Architecture Engineering, Bahauddin Zakariya University, Multan, Pakistan
| | - Su Xiaomei
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Chaofeng Shen
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Xianjin Tang
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China.
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15
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Abstract
Pseudomonas aeruginosa (P. aeruginosa) is a major cause of urinary tract and nosocomial infections. Here, we propose and demonstrate proof-of-principle for a potential cell therapy approach against P. aeruginosa. Using principles of synthetic biology, we genetically modified E. coli to specifically detect wild type P. aeruginosa (PAO1) via its quorum sensing (QS) molecule, 3OC 12 HSL. Engineered E. coli sentinels respond to the presence of 3OC 12 HSL by secreting CoPy, a novel pathogen-specific engineered chimeric bacteriocin, into the extracellular medium using the flagellar secretion tag FlgM. Extracellular FlgM-CoPy is designed to kill PAO1 specifically. CoPy was constructed by replacing the receptor and translocase domain of Colicin E3 with that of Pyocin S3. We show that CoPy toxicity is PAO1 specific, not affecting sentinel E. coli or the other bacterial strains tested. In order to define the system's basic requirements and PAO1-killing capabilities, we further determined the growth rates of PAO1 under different conditions and concentrations of purified and secreted FlgM-CoPy. The integrated system was tested by co-culturing PAO1 cells, on semisolid agar plates, together with engineered sentinel E. coli, capable of secreting FlgM-CoPy when induced by 3OC 12 HSL. Optical microscopy results show that the engineered E. coli sentinels successfully inhibit PAO1 growth.
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Affiliation(s)
- Saurabh Gupta
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
| | - Eran E. Bram
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
| | - Ron Weiss
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
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16
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de Avila e Silva S, Echeverrigaray S, Gerhardt GJ. BacPP: Bacterial promoter prediction—A tool for accurate sigma-factor specific assignment in enterobacteria. J Theor Biol 2011; 287:92-9. [DOI: 10.1016/j.jtbi.2011.07.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 05/20/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
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17
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Pui CF, Wong WC, Chai LC, Lee HY, Noorlis A, Zainazor TCT, Tang JYH, Ghazali FM, Cheah YK, Nakaguchi Y, Nishibuchi M, Radu S. Multiplex PCR for the concurrent detection and differentiation of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium. Trop Med Health 2011; 39:9-15. [PMID: 22028607 PMCID: PMC3153144 DOI: 10.2149/tmh.2010-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/02/2011] [Indexed: 11/11/2022] Open
Abstract
Salmonellosis outbreaks involving typhoid fever and human gastroenteritis are important diseases in tropical countries where hygienic conditions are often not maintained. A rapid and sensitive method to detect Salmonella spp., Salmonella Typhi and Salmonella Typhimurium is needed to improve control and surveillance of typhoid fever and Salmonella gastroenteritis. Our objective was the concurrent detection and differentiation of these food-borne pathogens using a multiplex PCR. We therefore designed and optimized a multiplex PCR using three specific PCR primer pairs for the simultaneous detection of these pathogens. The concentration of each of the primer pairs, magnesium chloride concentration, and primer annealing temperature were optimized before verification of the specificity of the primer pairs. The target genes produced amplicons at 429 bp, 300 bp and 620 bp which were shown to be 100% specific to each target bacterium, Salmonella spp., Salmonella Typhi and Salmonella Typhimurium, respectively.
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Affiliation(s)
- Chai Fung Pui
- Center of Excellence for Food Safety Research, Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
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18
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Ferooz J, Lemaire J, Letesson JJ. Role of FlbT in flagellin production in Brucella melitensis. MICROBIOLOGY-SGM 2011; 157:1253-1262. [PMID: 21273249 DOI: 10.1099/mic.0.044867-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It was recently demonstrated that the pathogen Brucella melitensis produces a polar sheathed flagellum under the control of the master regulator FtcR. However, the regulatory mechanism controlling the flagellar assembly remains unknown. In this work, we investigate the flagellar hierarchy of B. melitensis as well as the flagellin FliC regulation. We show that a mutation in fliF or flgE (coding for the basal body structure and the hook, respectively) does not affect FliC synthesis, suggesting that production of FliC does not depend on the flagellar assembly. We demonstrate that FlbT is a FliC activator since inactivation of flbT causes a decrease in fliC expression by using a fliC-lacZ translational reporter construct. Moreover, the quantitative real-time PCR and Western blot analysis show a marked decrease in fliC mRNA and FliC protein level, respectively. Conversely, the B. melitensis wild-type strain overexpressing flaF fails to produce FliC, suggesting an opposite function. Interestingly, the expression of the flbT gene in an ftcR or an flbT mutant restores FliC production, demonstrating that FlbT plays a regulatory checkpoint role in FliC synthesis. This mechanism could be conserved in the Rhizobiales since complementation of an flbT or an ftcR mutant with flbT from Sinorhizobium meliloti restores FliC synthesis.
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Affiliation(s)
- Jonathan Ferooz
- Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium
| | - Julien Lemaire
- Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium
| | - Jean-Jacques Letesson
- Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium
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JAMSHIDI A, KALIDARI G, HEDAYATI M. ISOLATION AND IDENTIFICATION OF SALMONELLAENTERITIDIS AND SALMONELLATYPHIMURIUM FROM THE EGGS OF RETAIL STORES IN MASHHAD, IRAN USING CONVENTIONAL CULTURE METHOD AND MULTIPLEX PCR ASSAY. J Food Saf 2010. [DOI: 10.1111/j.1745-4565.2010.00225.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Kthiri F, Le HT, Gautier V, Caldas T, Malki A, Landoulsi A, Bohn C, Bouloc P, Richarme G. Protein aggregation in a mutant deficient in yajL, the bacterial homolog of the Parkinsonism-associated protein DJ-1. J Biol Chem 2010; 285:10328-36. [PMID: 20124404 DOI: 10.1074/jbc.m109.077529] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
YajL is the closest prokaryotic homolog of the parkinsonism-associated protein DJ-1 (40% sequence identity and similar three-dimensional structure), a protein of unknown function involved in the cellular response to oxidative stress. We report here that a yajL mutant of Escherichia coli displays an increased sensitivity to oxidative stress. It also exhibits a protein aggregation phenotype in aerobiosis, but not in anaerobiosis or in aerobic cells overexpressing superoxide dismutase, suggesting that protein aggregation depends on the presence of reactive oxygen species produced by respiratory chains. The protein aggregation phenotype of the yajL mutant, which can be rescued by the wild-type yajL gene, but not by the corresponding cysteine 106 mutant allele, is similar to that of multiple mutants deficient in superoxide dismutases and catalases, although intracellular hydrogen peroxide levels were not increased in the yajL mutant, suggesting that protein aggregation in this strain does not result from a hydrogen peroxide detoxification defect. Aggregation-prone proteins included 17 ribosomal proteins, the ATP synthase beta subunit, flagellin, and the outer membrane proteins OmpA and PAL; all of them are part of multiprotein complexes, suggesting that YajL might be involved in optimal expression of these complexes, especially during oxidative stress. YajL stimulated the renaturation of urea-unfolded citrate synthase and the solubilization of the urea-unfolded ribosomal proteins S1 and L3 and was more efficient as a chaperone in its oxidized form than in its reduced form. The mRNA levels of several aggregated proteins of the yajL mutant were severely affected, suggesting that YajL also acts at the level of gene expression. These two functions of YajL might explain the protein aggregation phenotype of the yajL mutant.
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Affiliation(s)
- Fatoum Kthiri
- Stress Molecules, Institut Jacques Monod, Université Paris 7, 15 rue Hélène Brion, 75013 Paris, France
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21
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Chan YC, Wu HP, Chuang DY. Extracellular secretion of Carocin S1 in Pectobacterium carotovorum subsp. carotovorum occurs via the type III secretion system integral to the bacterial flagellum. BMC Microbiol 2009; 9:181. [PMID: 19712460 PMCID: PMC2744703 DOI: 10.1186/1471-2180-9-181] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 08/27/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pectobacterium carotovorum subsp. carotovorum is a phytopathogenic enterobacterium responsible for soft rot, a disease characterized by extensive maceration of the affected plant tissue. This species also produces two or more antibacterial substances called bacteriocins, which enhance its competitiveness against related rival species. However, the secretion mechanism for low-molecular-weight bacteriocin is still unknown. RESULTS A mutant (flhC::Tn5) that did not secrete the low-molecular-weight bacteriocin (LMWB), Carocin S1, was generated by Tn5 insertional mutagenesis. Sequence analysis indicated that this insertion disrupted open reading frame 2 (ORF2) and ORF3 of this strain. Deletion and rescue experiments indicated that ORF2 and ORF3 were both required for extracellular LMWB secretion. The ORF2 and ORF3 sequences showed high homology with the flhD and flhC gene sequences of Pectobacterium carotovorum subsp. atroseptica, Serratia marcescens, Yersinia enterocolitica, and Escherichia coli, indicating that they likely encoded key regulatory components of the type III flagella secretion system. CONCLUSION Thus, the extracellular export of Carocin S1 by Pectobacterium carotovorum subsp. carotovorum appears to utilize the type III secretion system integral to bacterial flagella.
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Affiliation(s)
- Yung-chieh Chan
- Department of Chemistry, National Chung-Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan, Republic of China
| | - Huang-Pin Wu
- Division of Pulmonary Medicine, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung, Taiwan, Republic of China
| | - Duen-yau Chuang
- Department of Chemistry, National Chung-Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan, Republic of China
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22
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Blaylock B, Sorg JA, Schneewind O. Yersinia enterocolitica type III secretion of YopR requires a structure in its mRNA. Mol Microbiol 2008; 70:1210-22. [PMID: 18976277 DOI: 10.1111/j.1365-2958.2008.06474.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Yersinia type III secretion machines transport substrate proteins into the extracellular medium or into the cytoplasm of host cells. Translational hybrids, involving genes that encode substrates as well as reporter proteins that otherwise cannot travel the type III pathway, identified signals that promote transport of effector Yops into host cells. Signals for the secretion of substrates into high calcium media were hitherto unknown. By exploiting attributes of translational hybrids between yopR, whose product is secreted, and genes that encode impassable proteins that jam the secretion machine, we isolated yopR mutations that abolish substrate recognition. Similar to effector Yops, an N-terminal or 5' signal in codons 1-11 is required to initiate YopR into the type III pathway. YopR secretion cannot be completed and translational hybrids cannot impose a block without a second signal, positioned at codons 131-149. Silent mutations in the second signal abrogate function and the phenotype of other mutations can be suppressed by secondary mutations predicted to restore base complementary in a 3' stem-loop structure of the yopR mRNA.
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Affiliation(s)
- Bill Blaylock
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA
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23
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Zhao K, Liu M, Burgess RR. Adaptation in bacterial flagellar and motility systems: from regulon members to 'foraging'-like behavior in E. coli. Nucleic Acids Res 2007; 35:4441-52. [PMID: 17576668 PMCID: PMC1935009 DOI: 10.1093/nar/gkm456] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bacterial flagellar motility and chemotaxis help cells to reach the most favorable environments and to successfully compete with other micro-organisms in response to external stimuli. Escherichia coli is a motile gram-negative bacterium, and the flagellar regulon in E. coli is controlled by a master regulator FlhDC as well as a second regulator, flagellum-specific sigma factor, σF. To define the physiological role of these two regulators, we carried out transcription profiling experiments to identify, on a genome-wide basis, genes under the control of these two regulators. In addition, the synchronized pattern of increasing CRP activity causing increasing FlhDC expression with decreasing carbon source quality, together with the apparent coupling of motility activity with the activation of motility and chemotaxis genes in poor quality carbon sources, highlights the importance of CRP activation in allowing E. coli to devote progressively more of its limited reserves to search out better conditions. In adaptation to a variety of carbon sources, the motile bacteria carry out tactical responses by increasing flagellar operation but restricting costly flagellar synthesis, indicating its capability of strategically using the precious energy in nutrient-poor environments for maximizing survival.
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Affiliation(s)
- Kai Zhao
- McArdle Laboratory for Cancer Research, Department of Genetics and Department of Computer Science, University of Wisconsin, Madison, WI 53706, USA
| | - Mingzhu Liu
- McArdle Laboratory for Cancer Research, Department of Genetics and Department of Computer Science, University of Wisconsin, Madison, WI 53706, USA
| | - Richard R. Burgess
- McArdle Laboratory for Cancer Research, Department of Genetics and Department of Computer Science, University of Wisconsin, Madison, WI 53706, USA
- *To whom correspondence should be addressed. +1-608-263-2635+1-608-262-2824
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24
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Rosu V, Chevance FFV, Karlinsey JE, Hirano T, Hughes KT. Translation inhibition of the Salmonella fliC gene by the fliC 5' untranslated region, fliC coding sequences, and FlgM. J Bacteriol 2006; 188:4497-507. [PMID: 16740956 PMCID: PMC1482935 DOI: 10.1128/jb.01552-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 5'-untranslated region (5'UTR) of the fliC flagellin gene of Salmonella contains sequences critical for efficient fliC mRNA translation coupled to assembly. In a previous study we used targeted mutagenesis of the 5' end of the fliC gene to isolate single base changes defective in fliC gene translation. This identified a predicted stem-loop structure, SL2, as an effector of normal fliC mRNA translation. A single base change (-38C:U) in the fliC 5'UTR resulted in a mutant that is defective in fliC mRNA translation and was chosen for this study. Motile (Mot+) revertants of the -38C:T mutant were isolated and characterized, yielding several unexpected results. Second-site suppressors that restored fliC translation and motility included mutations that disrupt a RNA duplex stem formed between RNA sequences in the fliC 5'UTR SL2 region (including a precise deletion of SL2) and bases early within the fliC-coding region. A stop codon mutation at position 80 of flgM also suppressed the -38C:T motility defect, while flgM mutants defective in anti-sigma28 activity had no effect on fliC translation. One remarkable mutation in the fliC 5'UTR (-15G:A) results in a translation defect by itself but, in combination with the -38C:U mutation, restores normal translation. These results suggests signals intrinsic to the fliC mRNA that have both positive and negative effects on fliC translation involving both RNA structure and interacting proteins.
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Affiliation(s)
- Valentina Rosu
- Department of Microbiology, University of Utah, Salt Lake City, UT 84112, USA
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