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Petano-Duque JM, Rueda-García V, Rondón-Barragán IS. Virulence genes identification in Salmonella enterica isolates from humans, crocodiles, and poultry farms from two regions in Colombia. Vet World 2023; 16:2096-2103. [PMID: 38023281 PMCID: PMC10668553 DOI: 10.14202/vetworld.2023.2096-2103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/11/2023] [Indexed: 12/01/2023] Open
Abstract
Background and Aim Salmonella spp. is frequently found in the digestive tract of birds and reptiles and transmitted to humans through food. Salmonellosis is a public health problem because of pathogenicity variability in strains for virulence factors. This study aimed to identify the virulence genes in Salmonella isolates from humans, crocodiles, broiler cloacas, and broiler carcasses from two departments of Colombia. Materials and Methods This study was conducted on 31 Salmonella enterica strains from humans with gastroenteritis (seven), crocodiles (seven), broiler cloacas (six), and broiler carcasses (12) from Tolima and Santander departments of Colombia, belonging to 21 serotypes. All samples were tested for Salmonella spp. using culture method on selective and non-selective mediums. Extraction of genomic DNA was performed from fresh colonies, DNA quality was verified by spectrophotometry and confirmed by amplification of InvA gene using conventional polymerase chain reaction (PCR). bapA, fimA, icmF, IroB, marT, mgtC, nlpI, oafA, pagN, siiD, spvC, spvR, spvB, Stn, and vexA genes were amplified by PCR. Results The most prevalent gene was bapA (100%), followed by marT (96.77%), mgtC (93.55%), and fimA (83.87%). Likewise, IroB (70.97%), Stn (67.74%), spvR (61.29%), pagN (54.84%), icmF (54.8%), and SiiD (45.16%) were positive for more than 50% of the strains. Furthermore, none of the isolates tested positive for the vexA gene. Salmonella isolates presented 26 virulence profiles. Conclusion This study reported 14 virulence genes in Salmonella spp. isolates from humans with gastroenteritis, crocodiles, and broiler cloacas and carcasses. The distribution of virulence genes differed among sources. This study could help in decision-making by health and sanitary authorities.
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Affiliation(s)
- Julieth Michel Petano-Duque
- Poultry Research Group, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Santa Helena Highs, Ibagué, Tolima, Colombia
- Research Group in Immunobiology and Pathogenesis, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Santa Helena Highs, Ibagué, Tolima, Colombia
| | - Valentina Rueda-García
- Research Group in Immunobiology and Pathogenesis, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Santa Helena Highs, Ibagué, Tolima, Colombia
| | - Iang Schroniltgen Rondón-Barragán
- Poultry Research Group, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Santa Helena Highs, Ibagué, Tolima, Colombia
- Research Group in Immunobiology and Pathogenesis, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Santa Helena Highs, Ibagué, Tolima, Colombia
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Quendera AP, Pinto SN, Pobre V, Antunes W, Bonifácio VDB, Arraiano CM, Andrade JM. The ribonuclease PNPase is a key regulator of biofilm formation in Listeria monocytogenes and affects invasion of host cells. NPJ Biofilms Microbiomes 2023; 9:34. [PMID: 37286543 DOI: 10.1038/s41522-023-00397-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 05/18/2023] [Indexed: 06/09/2023] Open
Abstract
Biofilms provide an environment that protects microorganisms from external stresses such as nutrient deprivation, antibiotic treatments, and immune defences, thereby creating favorable conditions for bacterial survival and pathogenesis. Here we show that the RNA-binding protein and ribonuclease polynucleotide phosphorylase (PNPase) is a positive regulator of biofilm formation in the human pathogen Listeria monocytogenes, a major responsible for food contamination in food-processing environments. The PNPase mutant strain produces less biofilm biomass and exhibits an altered biofilm morphology that is more susceptible to antibiotic treatment. Through biochemical assays and microscopical analysis, we demonstrate that PNPase is a previously unrecognized regulator of the composition of the biofilm extracellular matrix, greatly affecting the levels of proteins, extracellular DNA, and sugars. Noteworthy, we have adapted the use of the fluorescent complex ruthenium red-phenanthroline for the detection of polysaccharides in Listeria biofilms. Transcriptomic analysis of wild-type and PNPase mutant biofilms reveals that PNPase impacts many regulatory pathways associated with biofilm formation, particularly by affecting the expression of genes involved in the metabolism of carbohydrates (e.g., lmo0096 and lmo0783, encoding PTS components), of amino acids (e.g., lmo1984 and lmo2006, encoding biosynthetic enzymes) and in the Agr quorum sensing-like system (lmo0048-49). Moreover, we show that PNPase affects mRNA levels of the master regulator of virulence PrfA and PrfA-regulated genes, and these results could help to explain the reduced bacterial internalization in human cells of the ΔpnpA mutant. Overall, this work demonstrates that PNPase is an important post-transcriptional regulator for virulence and adaptation to the biofilm lifestyle of Gram-positive bacteria and highlights the expanding role of ribonucleases as critical players in pathogenicity.
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Affiliation(s)
- Ana Patrícia Quendera
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Avenida da República, 2780-901, Oeiras, Portugal
| | - Sandra Nunes Pinto
- Institute for Bioengineering and Biosciences (IBB) and Associate Laboratory-Institute for Health and Bioeconomy (i4HB), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Vânia Pobre
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Avenida da República, 2780-901, Oeiras, Portugal
| | - Wilson Antunes
- Laboratório de Imagem, Nanomorfologia e Espectroscopia de Raios-X (Linx) da Unidade Militar Laboratorial de Defesa Biológica e Química (UMLDBQ), Instituto Universitário Militar, Centro de Investigação, Inovação e Desenvolvimento da Academia Militar, Av. Dr Alfredo Bensaúde, 1100-471, Lisboa, Portugal
| | - Vasco D B Bonifácio
- Institute for Bioengineering and Biosciences (IBB) and Associate Laboratory-Institute for Health and Bioeconomy (i4HB), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
- Bioengineering Department, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Cecília Maria Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Avenida da República, 2780-901, Oeiras, Portugal
| | - José Marques Andrade
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Avenida da República, 2780-901, Oeiras, Portugal.
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3
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Di Bonaventura G, Picciani C, Lupetti V, Pompilio A. Comparative Proteomic Analysis of Protein Patterns of Stenotrophomonas maltophilia in Biofilm and Planktonic Lifestyles. Microorganisms 2023; 11:microorganisms11020442. [PMID: 36838406 PMCID: PMC9960084 DOI: 10.3390/microorganisms11020442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Stenotrophomonas maltophilia is a clinically relevant bacterial pathogen, particularly in cystic fibrosis (CF) patients. Despite the well-known ability to form biofilms inherently resistant to antibiotics and host immunity, many aspects involved in S. maltophilia biofilm formation are yet to be elucidated. In the present study, a proteomic approach was used to elucidate the differential protein expression patterns observed during the planktonic-to-biofilm transition of S. maltophilia Sm126, a strong biofilm producer causing chronic infection in a CF patient, to identify determinants potentially associated with S. maltophilia biofilm formation. In all, 57 proteins were differentially (3-fold; p < 0.01) expressed in biofilm cells compared with planktonic counterparts: 38 were overexpressed, and 19 were down-expressed. It is worth noting that 34 proteins were exclusively found in biofilm, mainly associated with quorum sensing-mediated intercellular communication, augmented glycolysis, amino acid metabolism, biosynthesis of secondary metabolites, phosphate signaling, response to nutrient starvation, and general stress. Further work is warranted to evaluate if these proteins can be suitable targets for developing anti-biofilm strategies effective against S. maltophilia.
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Affiliation(s)
- Giovanni Di Bonaventura
- Department of Medical, Oral, and Biotechnological Sciences, G. d’Annunzio University of Chieti-Pescara, Via dei Vestini, 31, 66100 Chieti, Italy
- Center for Advanced Studies and Technology, G. d’Annunzio University of Chieti-Pescara, Via L. Polacchi 11, 66100 Chieti, Italy
- Correspondence:
| | - Carla Picciani
- Department of Medical, Oral, and Biotechnological Sciences, G. d’Annunzio University of Chieti-Pescara, Via dei Vestini, 31, 66100 Chieti, Italy
- Center for Advanced Studies and Technology, G. d’Annunzio University of Chieti-Pescara, Via L. Polacchi 11, 66100 Chieti, Italy
| | - Veronica Lupetti
- Department of Medical, Oral, and Biotechnological Sciences, G. d’Annunzio University of Chieti-Pescara, Via dei Vestini, 31, 66100 Chieti, Italy
- Center for Advanced Studies and Technology, G. d’Annunzio University of Chieti-Pescara, Via L. Polacchi 11, 66100 Chieti, Italy
| | - Arianna Pompilio
- Department of Medical, Oral, and Biotechnological Sciences, G. d’Annunzio University of Chieti-Pescara, Via dei Vestini, 31, 66100 Chieti, Italy
- Center for Advanced Studies and Technology, G. d’Annunzio University of Chieti-Pescara, Via L. Polacchi 11, 66100 Chieti, Italy
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Roy R, You RI, Chang CH, Yang CY, Lin NT. Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii. Microorganisms 2021; 9:microorganisms9061336. [PMID: 34203028 PMCID: PMC8234194 DOI: 10.3390/microorganisms9061336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.
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Affiliation(s)
- Rakesh Roy
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Ren-In You
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Chan-Hua Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
| | - Nien-Tsung Lin
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
- Department of Microbiology, School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
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Avila-Calderón ED, Ruiz-Palma MDS, Aguilera-Arreola MG, Velázquez-Guadarrama N, Ruiz EA, Gomez-Lunar Z, Witonsky S, Contreras-Rodríguez A. Outer Membrane Vesicles of Gram-Negative Bacteria: An Outlook on Biogenesis. Front Microbiol 2021; 12:557902. [PMID: 33746909 PMCID: PMC7969528 DOI: 10.3389/fmicb.2021.557902] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
Outer membrane vesicles (OMVs) from Gram-negative bacteria were first described more than 50 years ago. However, the molecular mechanisms involved in biogenesis began to be studied only in the last few decades. Presently, the biogenesis and molecular mechanisms for their release are not completely known. This review covers the most recent information on cellular components involved in OMV biogenesis, such as lipoproteins and outer membrane proteins, lipopolysaccharide, phospholipids, quorum-sensing molecules, and flagella.
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Affiliation(s)
- Eric Daniel Avila-Calderón
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, CINVESTAV-IPN, México City, Mexico
| | - María Del Socorro Ruiz-Palma
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,División Químico Biológicas, Universidad Tecnológica de Tecámac, Tecámac, Mexico
| | - Ma Guadalupe Aguilera-Arreola
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Norma Velázquez-Guadarrama
- Unidad de Investigación en enfermedades infecciosas, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Enrico A Ruiz
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Zulema Gomez-Lunar
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Sharon Witonsky
- Center for One Health Research, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.,Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Araceli Contreras-Rodríguez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
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6
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Nevermann J, Silva A, Otero C, Oyarzún DP, Barrera B, Gil F, Calderón IL, Fuentes JA. Identification of Genes Involved in Biogenesis of Outer Membrane Vesicles (OMVs) in Salmonella enterica Serovar Typhi. Front Microbiol 2019; 10:104. [PMID: 30778340 PMCID: PMC6369716 DOI: 10.3389/fmicb.2019.00104] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/17/2019] [Indexed: 12/26/2022] Open
Abstract
Outer membrane vesicles (OMVs) are nano-sized proteoliposomes discharged from the cell envelope of Gram-negative bacteria. OMVs normally contain toxins, enzymes and other factors, and are used as vehicles in a process that has been considered a generalized, evolutionarily conserved delivery system among bacteria. Furthermore, OMVs can be used in biotechnological applications that require delivery of biomolecules, such as vaccines, remarking the importance of their study. Although it is known that Salmonella enterica serovar Typhi (S. Typhi), the etiological agent of typhoid fever in humans, delivers toxins (e.g., HlyE) via OMVs, there are no reports identifying genetic determinants of the OMV biogenesis in this serovar. In the present work, and with the aim to identify genes participating in OMV biogenesis in S. Typhi, we screened 15,000 random insertion mutants for increased HlyE secretion. We found 9 S. Typhi genes (generically called zzz genes) determining an increased HlyE secretion that were also involved in OMV biogenesis. The genes corresponded to ompA, nlpI, and tolR (envelope stability), rfaE and waaC (LPS synthesis), yipP (envC), mrcB (synthesis and remodeling of peptidoglycan), degS (stress sensor serine endopeptidase) and hns (global transcriptional regulator). We found that S. Typhi Δzzz mutants were prone to secrete periplasmic, functional proteins with a relatively good envelope integrity. In addition, we showed that zzz genes participate in OMV biogenesis, modulating different properties such as OMV size distribution, OMV yield and OMV protein cargo.
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Affiliation(s)
- Jan Nevermann
- Laboratorio de Genética y Patogénesis Bacteriana, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Andrés Silva
- Laboratorio de Genética y Patogénesis Bacteriana, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Carolina Otero
- Escuela de Química y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Diego P Oyarzún
- Center of Applied Nanosciences, Universidad Andres Bello, Santiago, Chile
| | - Boris Barrera
- Unidad de Microbiología, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Fernando Gil
- Microbiota-Host Interactions and Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Iván L Calderón
- Laboratorio de Genética y Patogénesis Bacteriana, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Juan A Fuentes
- Laboratorio de Genética y Patogénesis Bacteriana, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence. Infect Immun 2016; 84:1501-1513. [PMID: 26930706 DOI: 10.1128/iai.01463-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/24/2016] [Indexed: 12/16/2022] Open
Abstract
Neisseria meningitidis autoaggregation is an important step during attachment to human cells. Aggregation is mediated by type IV pili and can be modulated by accessory pilus proteins, such as PilX, and posttranslational modifications of the major pilus subunit PilE. The mechanisms underlying the regulation of aggregation remain poorly characterized. Polynucleotide phosphorylase (PNPase) is a 3'-5' exonuclease that is involved in RNA turnover and the regulation of small RNAs. In this study, we biochemically confirm that NMC0710 is the N. meningitidis PNPase, and we characterize its role in N. meningitidis pathogenesis. We show that deletion of the gene encoding PNPase leads to hyperaggregation and increased adhesion to epithelial cells. The aggregation induced was found to be dependent on pili and to be mediated by excessive pilus bundling. PNPase expression was induced following bacterial attachment to human cells. Deletion of PNPase led to global transcriptional changes and the differential regulation of 469 genes. We also demonstrate that PNPase is required for full virulence in an in vivo model of N. meningitidis infection. The present study shows that PNPase negatively affects aggregation, adhesion, and virulence in N. meningitidis.
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Transcriptome Sequencing Reveals Wide Expression Reprogramming of Basal and Unknown Genes in Leptospira biflexa Biofilms. mSphere 2016; 1:mSphere00042-16. [PMID: 27303713 PMCID: PMC4863578 DOI: 10.1128/msphere.00042-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/11/2016] [Indexed: 11/20/2022] Open
Abstract
In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis. The genus Leptospira is composed of pathogenic and saprophytic spirochetes. Pathogenic Leptospira is the etiological agent of leptospirosis, a globally spread neglected disease. A key ecological feature of some pathogenic species is their ability to survive both within and outside the host. For most leptospires, the ability to persist outside the host is associated with biofilm formation, a most important bacterial strategy to face and overcome hostile environmental conditions. The architecture and biochemistry of leptospiral biofilms are rather well understood; however, the genetic program underpinning biofilm formation remains mostly unknown. In this work, we used the saprophyte Leptospira biflexa as a model organism to assess over- and underrepresented transcripts during the biofilm state, using transcriptome sequencing (RNA-seq) technology. Our results showed that some basal biological processes like DNA replication and cell division are downregulated in the mature biofilm. Additionally, we identified significant expression reprogramming for genes involved in motility, sugar/lipid metabolism, and iron scavenging, as well as for outer membrane-encoding genes. A careful manual annotation process allowed us to assign molecular functions to many previously uncharacterized genes that are probably involved in biofilm metabolism. We also provided evidence for the presence of small regulatory RNAs in this species. Finally, coexpression networks were reconstructed to pinpoint functionally related gene clusters that may explain how biofilm maintenance is regulated. Beyond elucidating some genetic aspects of biofilm formation, this work reveals a number of pathways whose functional dissection may impact our understanding of leptospiral biology, in particular how these organisms adapt to environmental changes. IMPORTANCE In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis.
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MacKenzie KD, Wang Y, Shivak DJ, Wong CS, Hoffman LJL, Lam S, Kröger C, Cameron ADS, Townsend HGG, Köster W, White AP. Bistable expression of CsgD in Salmonella enterica serovar Typhimurium connects virulence to persistence. Infect Immun 2015; 83:2312-26. [PMID: 25824832 PMCID: PMC4432751 DOI: 10.1128/iai.00137-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/20/2015] [Indexed: 11/20/2022] Open
Abstract
Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogen Salmonella enterica serovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist when S. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allows S. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment.
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Affiliation(s)
- Keith D MacKenzie
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yejun Wang
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada
| | - Dylan J Shivak
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Cynthia S Wong
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada
| | - Leia J L Hoffman
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada
| | - Shirley Lam
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada
| | - Carsten Kröger
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Andrew D S Cameron
- Department of Biology, University of Regina, Regina, Saskatchewan, Canada
| | - Hugh G G Townsend
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Wolfgang Köster
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Aaron P White
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, Saskatchewan, Canada Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Tao J, Sang Y, Teng Q, Ni J, Yang Y, Tsui SKW, Yao YF. Heat shock proteins IbpA and IbpB are required for NlpI-participated cell division in Escherichia coli. Front Microbiol 2015; 6:51. [PMID: 25699035 PMCID: PMC4316790 DOI: 10.3389/fmicb.2015.00051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 01/15/2015] [Indexed: 11/29/2022] Open
Abstract
Lipoprotein NlpI of Escherichia coli is involved in the cell division, virulence, and bacterial interaction with eukaryotic host cells. To elucidate the functional mechanism of NlpI, we examined how NlpI affects cell division and found that induction of NlpI inhibits nucleoid division and halts cell growth. Consistent with these results, the cell division protein FtsZ failed to localize at the septum but diffused in the cytosol. Elevation of NlpI expression enhanced the transcription and the outer membrane localization of the heat shock protein IbpA and IbpB. Deletion of either ibpA or ibpB abolished the effects of NlpI induction, which could be restored by complementation. The C-terminus of NlpI is critical for the enhancement in IbpA and IbpB production, and the N-terminus of NlpI is required for the outer membrane localization of NlpI, IbpA, and IbpB. Furthermore, NlpI physically interacts with IbpB. These results indicate that over-expression of NlpI can interrupt the nucleoids division and the assembly of FtsZ at the septum, mediated by IbpA/IbpB, suggesting a role of the NlpI/IbpA/IbpB complex in the cell division.
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Affiliation(s)
- Jing Tao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Yu Sang
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Qihui Teng
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Jinjing Ni
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Yi Yang
- School of Biomedical Sciences, The Chinese University of Hong Kong Hong Kong, China
| | | | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
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11
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Bearson SMD, Bearson BL, Lee IS, Kich JD. Polynucleotide phosphorylase (PNPase) is required for Salmonella enterica serovar Typhimurium colonization in swine. Microb Pathog 2013; 65:63-6. [PMID: 24126127 DOI: 10.1016/j.micpath.2013.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/24/2013] [Accepted: 10/03/2013] [Indexed: 12/14/2022]
Abstract
The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA processing and degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for survival in an ex vivo swine stomach content assay. In the current study, attenuation and colonization potential of a S. Typhimurium pnp mutant in the porcine host was evaluated. Following intranasal inoculation with 10(9) cfu of either the wild-type S. Typhimurium χ4232 strain or an isogenic derivative lacking the pnp gene (n = 5/group), a significant increase (p < 0.05) in rectal temperature (fever) was observed in the pigs inoculated with wild-type S. Typhimurium compared to the pigs inoculated with the pnp mutant. Fecal shedding of the pnp mutant was significantly reduced during the 7-day study compared to the wild-type strain (p < 0.001). Tissue colonization was also significantly reduced in the pigs inoculated with the pnp mutant compared to the parental strain, including the tonsils, ileocecal lymph nodes, Peyer's Patch region of the ileum, cecum and contents of the cecum (p < 0.05). The data indicate that the pnp gene is required for S. Typhimurium virulence and gastrointestinal colonization of the natural swine host.
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Affiliation(s)
- S M D Bearson
- USDA/ARS/National Animal Disease Center, Ames, IA, USA.
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12
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Carzaniga T, Antoniani D, Dehò G, Briani F, Landini P. The RNA processing enzyme polynucleotide phosphorylase negatively controls biofilm formation by repressing poly-N-acetylglucosamine (PNAG) production in Escherichia coli C. BMC Microbiol 2012; 12:270. [PMID: 23171129 PMCID: PMC3571907 DOI: 10.1186/1471-2180-12-270] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/01/2012] [Indexed: 05/26/2023] Open
Abstract
Background Transition from planktonic cells to biofilm is mediated by production of adhesion factors, such as extracellular polysaccharides (EPS), and modulated by complex regulatory networks that, in addition to controlling production of adhesion factors, redirect bacterial cell metabolism to the biofilm mode. Results Deletion of the pnp gene, encoding polynucleotide phosphorylase, an RNA processing enzyme and a component of the RNA degradosome, results in increased biofilm formation in Escherichia coli. This effect is particularly pronounced in the E. coli strain C-1a, in which deletion of the pnp gene leads to strong cell aggregation in liquid medium. Cell aggregation is dependent on the EPS poly-N-acetylglucosamine (PNAG), thus suggesting negative regulation of the PNAG biosynthetic operon pgaABCD by PNPase. Indeed, pgaABCD transcript levels are higher in the pnp mutant. Negative control of pgaABCD expression by PNPase takes place at mRNA stability level and involves the 5’-untranslated region of the pgaABCD transcript, which serves as a cis-element regulating pgaABCD transcript stability and translatability. Conclusions Our results demonstrate that PNPase is necessary to maintain bacterial cells in the planktonic mode through down-regulation of pgaABCD expression and PNAG production.
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Affiliation(s)
- Thomas Carzaniga
- Department of Biosciences, University of Milan, Via Celoria 26, Milan, 20133, Italy
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13
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Rouf SF, Anwar N, Clements MO, Rhen M. Genetic analysis of the pnp-deaD genetic region reveals membrane lipoprotein NlpI as an independent participant in cold acclimatization of Salmonella enterica serovar Typhimurium. FEMS Microbiol Lett 2011; 325:56-63. [PMID: 22092862 DOI: 10.1111/j.1574-6968.2011.02416.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/31/2011] [Accepted: 09/02/2011] [Indexed: 11/26/2022] Open
Abstract
The cold acclimatization response in many bacterial species is a tightly regulated process, which ensures the correct folding of macromolecules. In enterobacteria, this response is in part dependent on polynucleotide phosphorylase, which is encoded by the gene pnp. Based on transcriptional analysis of the pnp locus of Salmonella enterica serovar Typhimurium, we show that pnp and the adjacent membrane lipoprotein nlpI gene form an operon with both genes contributing independently to the cold acclimatization response at 15 °C. Our findings thereby define a new role for NlpI in bacterial cold acclimatization.
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Affiliation(s)
- Syed Fazle Rouf
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Regulation of biofilm components in Salmonella enterica serovar Typhimurium by lytic transglycosylases involved in cell wall turnover. J Bacteriol 2011; 193:6443-51. [PMID: 21965572 DOI: 10.1128/jb.00425-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In Salmonella enterica serovar Typhimurium, a biofilm mode of growth known as the rdar morphotype is regulated by several networks which sense multiple environmental signals. The transcriptional regulator CsgD is the major target for these regulatory pathways. In this study, we show that two lytic transglycosylases of family I, MltE and MltC, in combination increase CsgD expression and rdar morphotype. MltE and MltC, which share a highly similar transglycosylase SLT domain, work redundantly to regulate CsgD at the transcriptional and posttranscriptional levels. The effect of MltE and MltC on CsgD levels was independent of the known regulatory pathways that sense cell envelope stress. These findings reveal, for the first time, a specific function of lytic transglycosylases in S. Typhimurium and suggest the existence of a new signaling pathway that links cell wall turnover to biofilm formation.
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