1
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Sherlock D, Fogg PCM. The archetypal gene transfer agent RcGTA is regulated via direct interaction with the enigmatic RNA polymerase omega subunit. Cell Rep 2022; 40:111183. [PMID: 35947951 PMCID: PMC9638019 DOI: 10.1016/j.celrep.2022.111183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/06/2022] [Accepted: 07/19/2022] [Indexed: 12/03/2022] Open
Abstract
Gene transfer agents (GTAs) are small virus-like particles that indiscriminately package and transfer any DNA present in their host cell, with clear implications for bacterial evolution. The first transcriptional regulator that directly controls GTA expression, GafA, was recently discovered, but its mechanism of action has remained elusive. Here, we demonstrate that GafA controls GTA gene expression via direct interaction with the RNA polymerase omega subunit (Rpo-ω) and also positively autoregulates its own expression by an Rpo-ω-independent mechanism. We show that GafA is a modular protein with distinct DNA and protein binding domains. The functional domains we observe in Rhodobacter GafA also correspond to two-gene operons in Hyphomicrobiales pathogens. These data allow us to produce the most complete regulatory model for a GTA and point toward an atypical mechanism for RNA polymerase recruitment and specific transcriptional activation in the Alphaproteobacteria.
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Affiliation(s)
- David Sherlock
- Biology Department, University of York, York YO10 5DD, UK
| | - Paul C M Fogg
- Biology Department, University of York, York YO10 5DD, UK; York Biomedical Research Institute (YBRI), University of York, York YO10 5NG, UK.
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2
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Mena-Bueno S, Poveda-Urkixo I, Irazoki O, Palacios L, Cava F, Zabalza-Baranguá A, Grilló MJ. Brucella melitensis Wzm/Wzt System: Changes in the Bacterial Envelope Lead to Improved Rev1Δwzm Vaccine Properties. Front Microbiol 2022; 13:908495. [PMID: 35875565 PMCID: PMC9306315 DOI: 10.3389/fmicb.2022.908495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The lipopolysaccharide (LPS) O-polysaccharide (O-PS) is the main virulence factor in Brucella. After synthesis in the cytoplasmic membrane, O-PS is exported to the periplasm by the Wzm/Wzt system, where it is assembled into a LPS. This translocation also engages a bactoprenol carrier required for further biosynthesis pathways, such as cell wall biogenesis. Targeting O-PS export by blockage holds great potential for vaccine development, but little is known about the biological implications of each Wzm/Wzt moiety. To improve this knowledge and to elucidate its potential application as a vaccine, we constructed and studied wzm/wzt single- and double-deletion mutants, using the attenuated strain Brucella melitensis Rev1 as the parental strain. This allowed us to describe the composition of Brucella peptidoglycan for the first time. We observed that these mutants lack external O-PS yet trigger changes in genetic transcription and in phenotypic properties associated with the outer membrane and cell wall. The three mutants are highly attenuated; unexpectedly, Rev1Δwzm also excels as an immunogenic and effective vaccine against B. melitensis and Brucella ovis in mice, revealing that low persistence is not at odds with efficacy. Rev1Δwzm is attenuated in BeWo trophoblasts, does not infect mouse placentas, and is safe in pregnant ewes. Overall, these attributes and the minimal serological interference induced in sheep make Rev1Δwzm a highly promising vaccine candidate.
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Affiliation(s)
- Sara Mena-Bueno
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- Agronomy, Biotecnology and Food Department, Universidad Pública de Navarra (UPNA), Pamplona, Spain
| | - Irati Poveda-Urkixo
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Leyre Palacios
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ana Zabalza-Baranguá
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - María Jesús Grilló
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- *Correspondence: María Jesús Grilló,
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3
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de la Garza-García JA, Ouahrani-Bettache S, Lyonnais S, Ornelas-Eusebio E, Freddi L, Al Dahouk S, Occhialini A, Köhler S. Comparative Genome-Wide Transcriptome Analysis of Brucella suis and Brucella microti Under Acid Stress at pH 4.5: Cold Shock Protein CspA and Dps Are Associated With Acid Resistance of B. microti. Front Microbiol 2021; 12:794535. [PMID: 34966374 PMCID: PMC8710502 DOI: 10.3389/fmicb.2021.794535] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
Brucellae are facultative intracellular coccobacilli causing brucellosis, one of the most widespread bacterial zoonosis affecting wildlife animals, livestock and humans. The genus Brucella comprises classical and atypical species, such as Brucella suis and Brucella microti, respectively. The latter is characterized by increased metabolic activity, fast growth rates, and extreme acid resistance at pH 2.5, suggesting an advantage for environmental survival. In addition, B. microti is more acid-tolerant than B. suis at the intermediate pH of 4.5. This acid-resistant phenotype of B. microti may have major implications for fitness in soil, food products and macrophages. Our study focused on the identification and characterization of acid resistance determinants of B. suis and B. microti in Gerhardt's minimal medium at pH 4.5 and 7.0 for 20 min and 2 h by comparative RNA-Seq-based transcriptome analysis, validated by RT-qPCR. Results yielded a common core response in both species with a total of 150 differentially expressed genes, and acidic pH-dependent genes regulated specifically in each species. The identified core response mechanisms comprise proton neutralization or extrusion from the cytosol, participating in maintaining physiological intracellular pH values. Differential expression of 441 genes revealed species-specific mechanisms in B. microti with rapid physiological adaptation to acid stress, anticipating potential damage to cellular components and critical energy conditions. Acid stress-induced genes encoding cold shock protein CspA, pseudogene in B. suis, and stress protein Dps were associated with survival of B. microti at pH 4.5. B. suis response with 284 specifically regulated genes suggested increased acid stress-mediated protein misfolding or damaging, triggering the set-up of repair strategies countering the consequences rather than the origin of acid stress and leading to subsequent loss of viability. In conclusion, our work supports the hypothesis that increased acid stress resistance of B. microti is based on selective pressure for the maintenance of functionality of critical genes, and on specific differential gene expression, resulting in rapid adaptation.
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Affiliation(s)
- Jorge A de la Garza-García
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | - Safia Ouahrani-Bettache
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | | | - Erika Ornelas-Eusebio
- Unité des Zoonoses Bactériennes and Unité d'Epidémiologie, Laboratoire de Santé Animale, ANSES, University Paris-Est, Maisons-Alfort, France
| | - Luca Freddi
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | | | - Alessandra Occhialini
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | - Stephan Köhler
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
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4
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Sauceda-Becerra R, Barrios-García H, Martínez-Burnes J, Arellano-Reynoso B, Benítez-Guzmán A, Hernández-Castro R, Alva-Pérez J. Brucella melitensis invA gene (BME_RS01060) transcription is promoted under acidic stress conditions. Arch Microbiol 2021; 204:52. [DOI: 10.1007/s00203-021-02664-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 10/19/2022]
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5
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Tilocca B, Soggiu A, Greco V, Sacchini F, Garofolo G, Paci V, Bonizzi L, Urbani A, Tittarelli M, Roncada P. Comparative proteomics of Brucella melitensis is a useful toolbox for developing prophylactic interventions in a One-Health context. One Health 2021; 13:100253. [PMID: 33997237 PMCID: PMC8100217 DOI: 10.1016/j.onehlt.2021.100253] [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: 02/17/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/28/2022] Open
Abstract
Brucellosis caused by Brucella melitensis is a zoonosis frequently reported in the Mediterranean and Middle-East regions and responsible for important economic losses and reduced animal welfare. To date, current strategies applied to control or eradicate the disease relies on diagnostic tests that suffer from limited specificity in non-vaccinated animals; while prophylactic measures, when applied, use a live attenuated bacterial strain characterized by residual virulence on adult pregnant animals and difficulties in distinguishing vaccinated from infected animals. To overcome these issues, studies are desired to elucidate the bacterial biology and the pathogenetic mechanisms of both the vaccinal strain and the pathogenic strains. Proteomics has a potential in tackling issues of One-Health concern; here, we employed label-free shotgun proteomics to investigate the protein repertoire of the vaccinal strain B. melitensis Rev.1 and compare it with the proteome of the Brucella melitensis 16 M, a reference strain representative of B. melitensis field strains. Comparative proteomics profiling underlines common and diverging traits between the two strains. Common features suggest the potential biochemical routes responsible for the residual virulence of the vaccinal strain, whilst the diverging traits are suggestive biochemical signatures to be further investigated to provide an optimized diagnostic capable of discriminating the vaccinated from infected animals. The data presented in this study are openly available in PRIDE data repository at https://www.ebi.ac.uk/pride/, reference number PXD022472.
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Affiliation(s)
- Bruno Tilocca
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
| | - Alessio Soggiu
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Viviana Greco
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Flavio Sacchini
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Giuliano Garofolo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Valentina Paci
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Luigi Bonizzi
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Andrea Urbani
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Manuela Tittarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Paola Roncada
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
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6
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Rajendhran J. Genomic insights into Brucella. INFECTION GENETICS AND EVOLUTION 2020; 87:104635. [PMID: 33189905 DOI: 10.1016/j.meegid.2020.104635] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 01/21/2023]
Abstract
Brucellosis is a zoonotic disease caused by certain species of Brucella. Each species has its preferred host animal, though it can infect other animals too. For a longer period, only six classical species were recognized in the genus Brucella. No vaccine is available for human brucellosis. Therefore, human brucellosis can be controlled only by controlling brucellosis in animals. The genus is now expanding with the newly isolated atypical strains from various animals, including marine mammals. Presently, 12 species of Brucella have been recognized. The first genome of Brucella was released in 2002, and today, we have more than 1500 genomes of Brucella spp. isolated worldwide. Multiple genome sequences are available for the major zoonotic species, B. abortus, B. melitensis, and B. suis. The Brucella genome has two chromosomes with the approximate sizes of 2.1 and 1.2 Mbp. The genome of Brucella is highly conserved across all the species at the nucleotide level. One of the unanswered questions is what makes host preference in different species of Brucella. Here, I summarize the recent advancements in the Brucella genomics research.
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Affiliation(s)
- Jeyaprakash Rajendhran
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
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7
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Kornspan D, Zahavi T, Salmon-Divon M. The Acidic Stress Response of the Intracellular Pathogen Brucella melitensis: New Insights from a Comparative, Genome-Wide Transcriptome Analysis. Genes (Basel) 2020; 11:genes11091016. [PMID: 32872264 PMCID: PMC7563570 DOI: 10.3390/genes11091016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
The intracellular pathogenic bacteria belonging to the genus Brucella must cope with acidic stress as they penetrate the host via the gastrointestinal route, and again during the initial stages of intracellular infection. A transcription-level regulation has been proposed to explain this but the specific molecular mechanisms are yet to be determined. We recently reported a comparative transcriptomic analysis of the attenuated vaccine Brucella melitensis strain Rev.1 against the virulent strain 16M in cultures grown under either neutral or acidic conditions. Here, we re-analyze the RNA-seq data of 16M from our previous study and compare it to published transcriptomic data of this strain from both an in cellulo and an in vivo model. We identify 588 genes that are exclusively differentially expressed in 16M grown under acidic versus neutral pH conditions, including 286 upregulated genes and 302 downregulated genes that are not differentially expressed in either the in cellulo or the in vivo model. Of these, we highlight 13 key genes that are known to be associated with a bacterial response to acidic stress and, in our study, were highly upregulated under acidic conditions. These genes provide new molecular insights into the mechanisms underlying the acid-resistance of Brucella within its host.
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Affiliation(s)
- David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50250, Israel
- Correspondence: ; Tel.: +972-3-968-1745
| | - Tamar Zahavi
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
| | - Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
- Adelson School of Medicine, Ariel University, Ariel 40700, Israel
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8
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Budnick JA, Sheehan LM, Benton AH, Pitzer JE, Kang L, Michalak P, Roop RM, Caswell CC. Characterizing the transport and utilization of the neurotransmitter GABA in the bacterial pathogen Brucella abortus. PLoS One 2020; 15:e0237371. [PMID: 32845904 PMCID: PMC7449393 DOI: 10.1371/journal.pone.0237371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/04/2020] [Indexed: 01/18/2023] Open
Abstract
The neurotransmitter gamma-aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter in the human brain; however, it is becoming more evident that this non-proteinogenic amino acid plays multiple physiological roles in biology. In the present study, the transport and function of GABA is studied in the highly infectious intracellular bacterium Brucella abortus. The data show that 3H-GABA is imported by B. abortus under nutrient limiting conditions and that the small RNAs AbcR1 and AbcR2 negatively regulate this transport. A specific transport system, gts, is responsible for the transport of GABA as determined by measuring 3H-GABA transport in isogenic deletion strains of known AbcR1/2 regulatory targets; however, this locus is unnecessary for Brucella infection in BALB/c mice. Similar assays revealed that 3H-GABA transport is uninhibited by the 20 standard proteinogenic amino acids, representing preference for the transport of 3H-GABA. Metabolic studies did not show any potential metabolic utilization of GABA by B. abortus as a carbon or nitrogen source, and RNA sequencing analysis revealed limited transcriptional differences between B. abortus 2308 with or without exposure to GABA. While this study provides evidence for GABA transport by B. abortus, questions remain as to why and when this transport is utilized during Brucella pathogenesis.
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Affiliation(s)
- James A. Budnick
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, United States of America
- Center for One Health Research, Blacksburg, Virginia, United States of America
| | - Lauren M. Sheehan
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, United States of America
- Center for One Health Research, Blacksburg, Virginia, United States of America
| | - Angela H. Benton
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, United States of America
- Center for One Health Research, Blacksburg, Virginia, United States of America
| | - Joshua E. Pitzer
- Department of Microbiology and Immunology, East Carolina University Brody School of Medicine, Greenville, North Carolina, United States of America
| | - Lin Kang
- Center for One Health Research, Blacksburg, Virginia, United States of America
- Edward Via College of Osteopathic Medicine, Blacksburg, Virginia, United States of America
| | - Pawel Michalak
- Center for One Health Research, Blacksburg, Virginia, United States of America
- Edward Via College of Osteopathic Medicine, Blacksburg, Virginia, United States of America
- Institute of Evolution, University of Haifa, Haifa, Israel
| | - R. Martin Roop
- Department of Microbiology and Immunology, East Carolina University Brody School of Medicine, Greenville, North Carolina, United States of America
| | - Clayton C. Caswell
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, United States of America
- Center for One Health Research, Blacksburg, Virginia, United States of America
- * E-mail:
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9
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Transcriptomic determinants of the response of ST-111 Pseudomonas aeruginosa AG1 to ciprofloxacin identified by a top-down systems biology approach. Sci Rep 2020; 10:13717. [PMID: 32792590 PMCID: PMC7427096 DOI: 10.1038/s41598-020-70581-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/25/2020] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that thrives in diverse environments and causes a variety of human infections. Pseudomonas aeruginosa AG1 (PaeAG1) is a high-risk sequence type 111 (ST-111) strain isolated from a Costa Rican hospital in 2010. PaeAG1 has both blaVIM-2 and blaIMP-18 genes encoding for metallo-β-lactamases, and it is resistant to β-lactams (including carbapenems), aminoglycosides, and fluoroquinolones. Ciprofloxacin (CIP) is an antibiotic commonly used to treat P. aeruginosa infections, and it is known to produce DNA damage, triggering a complex molecular response. In order to evaluate the effects of a sub-inhibitory CIP concentration on PaeAG1, growth curves using increasing CIP concentrations were compared. We then measured gene expression using RNA-Seq at three time points (0, 2.5 and 5 h) after CIP exposure to identify the transcriptomic determinants of the response (i.e. hub genes, gene clusters and enriched pathways). Changes in expression were determined using differential expression analysis and network analysis using a top–down systems biology approach. A hybrid model using database-based and co-expression analysis approaches was implemented to predict gene–gene interactions. We observed a reduction of the growth curve rate as the sub-inhibitory CIP concentrations were increased. In the transcriptomic analysis, we detected that over time CIP treatment resulted in the differential expression of 518 genes, showing a complex impact at the molecular level. The transcriptomic determinants were 14 hub genes, multiple gene clusters at different levels (associated to hub genes or as co-expression modules) and 15 enriched pathways. Down-regulation of genes implicated in several metabolism pathways, virulence elements and ribosomal activity was observed. In contrast, amino acid catabolism, RpoS factor, proteases, and phenazines genes were up-regulated. Remarkably, > 80 resident-phage genes were up-regulated after CIP treatment, which was validated at phenomic level using a phage plaque assay. Thus, reduction of the growth curve rate and increasing phage induction was evidenced as the CIP concentrations were increased. In summary, transcriptomic and network analyses, as well as the growth curves and phage plaque assays provide evidence that PaeAG1 presents a complex, concentration-dependent response to sub-inhibitory CIP exposure, showing pleiotropic effects at the systems level. Manipulation of these determinants, such as phage genes, could be used to gain more insights about the regulation of responses in PaeAG1 as well as the identification of possible therapeutic targets. To our knowledge, this is the first report of the transcriptomic analysis of CIP response in a ST-111 high-risk P. aeruginosa strain, in particular using a top-down systems biology approach.
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10
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Potential druggable proteins and chimeric vaccine construct prioritization against Brucella melitensis from species core genome data. Genomics 2020; 112:1734-1745. [DOI: 10.1016/j.ygeno.2019.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/05/2019] [Accepted: 10/01/2019] [Indexed: 02/06/2023]
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11
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Zhang Y, Liu H, Gu D, Lu X, Zhou X, Xia X. Transcriptomic analysis of PhoR reveals its role in regulation of swarming motility and T3SS expression in Vibrio parahaemolyticus. Microbiol Res 2020; 235:126448. [PMID: 32114363 DOI: 10.1016/j.micres.2020.126448] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 01/14/2023]
Abstract
Vibrio parahaemolyticus is a common foodborne pathogen in seafood and represents a major threat to human health worldwide. In this study, we identified that PhoR, a histidine kinase, is involved in the regulation of swarming and flagella assembly. RNA sequencing analysis showed that 1122 genes were differentially expressed in PhoR mutant, including 394 upregulated and 728 downregulated genes. KEGG enrichment and heatmap analysis demonstrated that the bacterial secretion system, flagella assembly and chemotaxis pathways were significantly downregulated in PhoR mutant, while the microbial metabolism in diverse environments and carbon metabolism pathways were upregulated in PhoR mutant. qRT-PCR further confirmed that genes responsible for the type III secretion system (T3SS), swarming and the thermostable direct hemolysin were positively regulated by PhoR. Phosphorylation assays suggested that PhoR was highly activated in BHI medium compared to LB medium. Taken together, these data suggested that activated PhoR contributes to the expression of swarming motility and secretion system genes in Vibrio parahaemolyticus.
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Affiliation(s)
- Yibei Zhang
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China; Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269-3089, USA
| | - Huanhuan Liu
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Dan Gu
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Xingxu Lu
- Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA
| | - Xiaohui Zhou
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269-3089, USA.
| | - Xiaodong Xia
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China; School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, 1 Qinggongyuan, Ganjingzi District, Dalian, Liaoning, 116034 China.
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12
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Salmon-Divon M, Kornspan D. Transcriptomic analysis of smooth versus rough Brucella melitensis Rev.1 vaccine strains reveals insights into virulence attenuation. Int J Med Microbiol 2019; 310:151363. [PMID: 31699441 DOI: 10.1016/j.ijmm.2019.151363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/10/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022] Open
Abstract
Brucella melitensis Rev.1 is the live attenuated Elberg-originated vaccine strain of the facultative intracellular Brucella species, and is widely used to control brucellosis in small ruminants. However, Rev.1 may cause abortions in small ruminants that have been vaccinated during the last trimester of gestation, it is pathogenic to humans, and it induces antibodies directed at the O-polysaccharide (O-PS) of the smooth lipopolysaccharide, thus making it difficult to distinguish between vaccinated and infected animals. Rough Brucella strains, which lack O-PS and are considered less pathogenic, have been introduced to address these drawbacks; however, as Rev.1 confers a much better immunity than the rough mutants, it is still considered the reference vaccine for the prophylaxis of brucellosis in small ruminants. Therefore, developing an improved vaccine strain, which lacks the Rev.1 drawbacks, is a highly evaluated task, which requires a better understanding of the molecular mechanisms underlying the virulence attenuation of Rev.1 smooth strains and of natural Rev.1 rough strains, which are currently only partly understood. As the acidification of the Brucella-containing vacuole during the initial stages of infection is crucial for their survival, identifying the genes that contribute to their survival in an acidic environment versus a normal environment will greatly assist our understanding of the molecular pathogenic mechanisms and the attenuated virulence of the Rev.1 strain. Here, we compared the transcriptomes of the smooth and natural rough Rev.1 strains, each grown under either normal or acidic conditions. We found 12 key genes that are significantly downregulated in the Rev.1 rough strains under normal pH, as compared with Rev.1 smooth strains, and six highly important genes that are significantly upregulated in the smooth strains under acidic conditions, as compared with Rev.1 rough strains. All 18 differentially expressed genes are associated with bacterial virulence and survival and may explain the attenuated virulence of the rough Rev.1 strains versus smooth Rev.1 strains, thus providing new insights into the virulence attenuation mechanisms of Brucella. These highly important candidate genes may facilitate the design of new and improved brucellosis vaccines.
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Affiliation(s)
- Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel, Israel; Adelson School of Medicine, Ariel University, Israel.
| | - David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel.
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Gheibi A, Khanahmad H, Kardar GA, Boshtam M, Rezaie S, Kazemi B, Khorramizadeh MR. Optimization and Comparison of Different Methods and Factors for Efficient Transformation of Brucella abortus RB51strain. Adv Biomed Res 2019; 8:37. [PMID: 31198771 PMCID: PMC6555225 DOI: 10.4103/abr.abr_14_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: The development of protective vaccines for Brucella spp. has been hampered by the difficulty in transformation of Brucella cells with foreign DNA for genetic manipulation. It seems that the formation of Brucella spheroplasts would increase the efficiency of transformation. The aim of this study was to devise an efficient method for the transformation of Brucella spp. Materials and Methods: At first, spheroplast of Brucella was prepared by glycine and ampicillin induction and transformed using optimized protocols of CaCl2, electroporation, and lipofection methods. Then, the efficacy of transformation was compared between the three-mentioned methods. Results: Ampicillin-induced spheroplasts from early-log phase culture of brucella when incubated in a medium-containing 0.2 M sucrose during cell recovery had higher transformation efficiency in three different methods. Comparison of the transformation efficiency of Brucella abortus RB51 using the CaCl2, lipofection, and electroporation methods revealed that the transformation efficiency with the lipofection method was significantly higher than with other two methods (P < 0.05). Conclusions: Lipofection method by lipofectamine 2000 on ampicillin-induced spheroplasts can be a suitable approach for Brucella transformation.
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Affiliation(s)
- Azam Gheibi
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Gholam Ali Kardar
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Department of Immunology, Asthma and Allergy Research Institute, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Boshtam
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sassan Rezaie
- Department of Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Kazemi
- Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Khorramizadeh
- Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
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