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Hao M, Wang M, Zhao D, Shi Y, Yuan Y, Li J, Zhai Y, Liu X, Zhou D, Chen H, Lin P, Tang K, Liu W, Jin Y, Wang A. Alr Gene in Brucella suis S2: Its Role in Lipopolysaccharide Biosynthesis and Bacterial Virulence in RAW264.7. Int J Mol Sci 2023; 24:10744. [PMID: 37445922 DOI: 10.3390/ijms241310744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/24/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Brucella suis, the causative agent of brucellosis, poses a significant public health and animal husbandry threat. However, the role of the alanine racemase (alr) gene, which encodes alanine racemase in Brucella, remains unclear. Here, we analyzed an alr deletion mutant and a complemented strain of Brucella suis S2. The knockout strain displayed an unaltered, smooth phenotype in acriflavine agglutination tests but lacked the core polysaccharide portion of lipopolysaccharide (LPS). Genes involved in the LPS synthesis were significantly upregulated in the deletion mutant. The alr deletion strain exhibited reduced intracellular viability in the macrophages, increased macrophage-mediated killing, and upregulation of the apoptosis markers. Bcl2, an anti-apoptotic protein, was downregulated, while the pro-apoptotic proteins, Bax, Caspase-9, and Caspase-3, were upregulated in the macrophages infected with the deletion strain. The infected macrophages showed increased mitochondrial membrane permeability, Cytochrome C release, and reactive oxygen species, activating the mitochondrial apoptosis pathway. These findings revealed that alanine racemase was dispensable in B. suis S2 but influenced the strain's rough features and triggered the mitochondrial apoptosis pathway during macrophage invasion. The deletion of the alr gene reduced the intracellular survival and virulence. This study enhances our understanding of the molecular mechanism underlying Brucella's survival and virulence and, specifically, how alr gene affects host immune evasion by regulating bacterial LPS biosynthesis.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Ye Yuan
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Huatao Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Pengfei Lin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Keqiong Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
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Moreno E, Blasco JM, Moriyón I. Facing the Human and Animal Brucellosis Conundrums: The Forgotten Lessons. Microorganisms 2022; 10:942. [PMID: 35630386 PMCID: PMC9144488 DOI: 10.3390/microorganisms10050942] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/22/2022] [Accepted: 04/28/2022] [Indexed: 11/17/2022] Open
Abstract
Brucellosis is a major zoonotic disease caused by Brucella species. Historically, the disease received over fifty names until it was recognized as a single entity, illustrating its protean manifestations and intricacies, traits that generated conundrums that have remained or re-emerged since they were first described. Here, we examine confusions concerning the clinical picture, serological diagnosis, and incidence of human brucellosis. We also discuss knowledge gaps and prevalent confusions about animal brucellosis, including brucellosis control strategies, the so-called confirmatory tests, and assumptions about the primary-binding assays and DNA detection methods. We describe how doubtfully characterized vaccines have failed to control brucellosis and emphasize how the requisites of controlled safety and protection experiments are generally overlooked. Finally, we briefly discuss the experience demonstrating that S19 remains the best cattle vaccine, while RB51 fails to validate its claimed properties (protection, differentiating infected and vaccinated animals (DIVA), and safety), offering a strong argument against its current widespread use. These conundrums show that knowledge dealing with brucellosis is lost, and previous experience is overlooked or misinterpreted, as illustrated in a significant number of misguided meta-analyses. In a global context of intensifying livestock breeding, such recurrent oversights threaten to increase the impact of brucellosis.
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Affiliation(s)
- Edgardo Moreno
- Tropical Disease Research Program, National University, Heredia 40104, Costa Rica;
| | | | - Ignacio Moriyón
- Institute for Tropical Health and Department of Microbiology and Parasitology, Medical School, University of Navarra and IdISNA, 31008 Pamplona, Spain
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3
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Karthik K, Anbazhagan S, Thomas P, Ananda Chitra M, Senthilkumar TMA, Sridhar R, Dhinakar Raj G. Genome Sequencing and Comparative Genomics of Indian Isolates of Brucella melitensis. Front Microbiol 2021; 12:698069. [PMID: 34489888 PMCID: PMC8417702 DOI: 10.3389/fmicb.2021.698069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/19/2021] [Indexed: 11/25/2022] Open
Abstract
Brucella melitensis causes small ruminant brucellosis and a zoonotic pathogen prevalent worldwide. Whole genome phylogeny of all available B. melitensis genomes (n = 355) revealed that all Indian isolates (n = 16) clustered in the East Mediterranean lineage except the ADMAS-GI strain. Pangenome analysis indicated the presence of limited accessory genomes with few clades showing specific gene presence/absence pattern. A total of 43 virulence genes were predicted in all the Indian strains of B. melitensis except 2007BM-1 (ricA and wbkA are absent). Multilocus sequence typing (MLST) analysis indicated all except one Indian strain (ADMAS-GI) falling into sequence type (ST 8). In comparison with MLST, core genome phylogeny indicated two major clusters (>70% bootstrap support values) among Indian strains. Clusters with <70% bootstrap support values represent strains with diverse evolutionary origins present among animal and human hosts. Genetic relatedness among animal (sheep and goats) and human strains with 100% bootstrap values shows its zoonotic transfer potentiality. SNP-based analysis indicated similar clustering to that of core genome phylogeny. Among the Indian strains, the highest number of unique SNPs (112 SNPs) were shared by a node that involved three strains from Tamil Nadu. The node SNPs involved several peptidase genes like U32, M16 inactive domain protein, clp protease family protein, and M23 family protein and mostly represented non-synonymous (NS) substitutions. Vaccination has been followed in several parts of the world to prevent small ruminant brucellosis but not in India. Comparison of Indian strains with vaccine strains showed that M5 is genetically closer to most of the Indian strains than Rev.1 strain. The presence of most of the virulence genes among all Indian strains and conserved core genome compositions suggest the use of any circulating strain/genotypes for the development of a vaccine candidate for small ruminant brucellosis in India.
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Affiliation(s)
- Kumaragurubaran Karthik
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | - Subbaiyan Anbazhagan
- Division of Bacteriology and Mycology, Indian Veterinary Research Institute, Bareilly, India
| | - Prasad Thomas
- Division of Bacteriology and Mycology, Indian Veterinary Research Institute, Bareilly, India
| | - Murugesan Ananda Chitra
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | | | - Ramaswamy Sridhar
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | - Gopal Dhinakar Raj
- Centre for Animal Health Studies, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
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Stranahan LW, Arenas-Gamboa AM. When the Going Gets Rough: The Significance of Brucella Lipopolysaccharide Phenotype in Host-Pathogen Interactions. Front Microbiol 2021; 12:713157. [PMID: 34335551 PMCID: PMC8319746 DOI: 10.3389/fmicb.2021.713157] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/22/2021] [Indexed: 01/18/2023] Open
Abstract
Brucella is a facultatively intracellular bacterial pathogen and the cause of worldwide zoonotic infections, infamous for its ability to evade the immune system and persist chronically within host cells. Despite the frequent association with attenuation in other Gram-negative bacteria, a rough lipopolysaccharide phenotype is retained by Brucella canis and Brucella ovis, which remain fully virulent in their natural canine and ovine hosts, respectively. While these natural rough strains lack the O-polysaccharide they, like their smooth counterparts, are able to evade and manipulate the host immune system by exhibiting low endotoxic activity, resisting destruction by complement and antimicrobial peptides, entering and trafficking within host cells along a similar pathway, and interfering with MHC-II antigen presentation. B. canis and B. ovis appear to have compensated for their roughness by alterations to their outer membrane, especially in regards to outer membrane proteins. B. canis, in particular, also shows evidence of being less proinflammatory in vivo, suggesting that the rough phenotype may be associated with an enhanced level of stealth that could allow these pathogens to persist for longer periods of time undetected. Nevertheless, much additional work is required to understand the correlates of immune protection against the natural rough Brucella spp., a critical step toward development of much-needed vaccines. This review will highlight the significance of rough lipopolysaccharide in the context of both natural disease and host–pathogen interactions with an emphasis on natural rough Brucella spp. and the implications for vaccine development.
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Affiliation(s)
- Lauren W Stranahan
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Angela M Arenas-Gamboa
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
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5
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Herrou J, Willett JW, Fiebig A, Varesio LM, Czyż DM, Cheng JX, Ultee E, Briegel A, Bigelow L, Babnigg G, Kim Y, Crosson S. Periplasmic protein EipA determines envelope stress resistance and virulence in Brucella abortus. Mol Microbiol 2019; 111:637-661. [PMID: 30536925 DOI: 10.1111/mmi.14178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2018] [Indexed: 12/17/2022]
Abstract
Molecular components of the Brucella abortus cell envelope play a major role in its ability to infect, colonize and survive inside mammalian host cells. In this study, we have defined a role for a conserved gene of unknown function in B. abortus envelope stress resistance and infection. Expression of this gene, which we name eipA, is directly activated by the essential cell cycle regulator, CtrA. eipA encodes a soluble periplasmic protein that adopts an unusual eight-stranded β-barrel fold. Deletion of eipA attenuates replication and survival in macrophage and mouse infection models, and results in sensitivity to treatments that compromise the cell envelope integrity. Transposon disruption of genes required for LPS O-polysaccharide biosynthesis is synthetically lethal with eipA deletion. This genetic connection between O-polysaccharide and eipA is corroborated by our discovery that eipA is essential in Brucella ovis, a naturally rough species that harbors mutations in several genes required for O-polysaccharide production. Conditional depletion of eipA expression in B. ovis results in a cell chaining phenotype, providing evidence that eipA directly or indirectly influences cell division in Brucella. We conclude that EipA is a molecular determinant of Brucella virulence that functions to maintain cell envelope integrity and influences cell division.
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Affiliation(s)
- Julien Herrou
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Jonathan W Willett
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Aretha Fiebig
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Lydia M Varesio
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Daniel M Czyż
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Jason X Cheng
- Department of Pathology, The University of Chicago, Chicago, IL, USA
| | - Eveline Ultee
- Department of Biology, Universiteit Leiden, Leiden, Netherlands
| | - Ariane Briegel
- Department of Biology, Universiteit Leiden, Leiden, Netherlands
| | - Lance Bigelow
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Gyorgy Babnigg
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Youngchang Kim
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Sean Crosson
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
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6
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Cosford KL. Brucella canis: An update on research and clinical management. THE CANADIAN VETERINARY JOURNAL = LA REVUE VETERINAIRE CANADIENNE 2018; 59:74-81. [PMID: 29302106 PMCID: PMC5731389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In Canada, Brucella canis remains a potentially devastating infectious agent that is still considered uncommon, despite the increasing international movement of dogs. There may be a growing risk to the Canadian canine population due to a reliance on outdated seroprevalence studies and the lack of federal regulation. With the complex diagnostic and management challenges associated with Brucella canis, a One Health approach is necessary to address the need for ongoing research, including updating canine and human seroprevalence rates in Canada, elucidating the pathogenesis, and determining the most appropriate treatment and prevention strategies. Clinical management decisions are often complicated by currently available treatment protocols, and health risks to both canine and human populations. This article integrates recent research focusing on the pathogenesis, diagnosis, and treatment of Brucella canis, and outlines current clinical management approaches.
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Suárez-Esquivel M, Ruiz-Villalobos N, Castillo-Zeledón A, Jiménez-Rojas C, Roop Ii RM, Comerci DJ, Barquero-Calvo E, Chacón-Díaz C, Caswell CC, Baker KS, Chaves-Olarte E, Thomson NR, Moreno E, Letesson JJ, De Bolle X, Guzmán-Verri C. Brucella abortus Strain 2308 Wisconsin Genome: Importance of the Definition of Reference Strains. Front Microbiol 2016; 7:1557. [PMID: 27746773 PMCID: PMC5041503 DOI: 10.3389/fmicb.2016.01557] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 09/16/2016] [Indexed: 12/25/2022] Open
Abstract
Brucellosis is a bacterial infectious disease affecting a wide range of mammals and a neglected zoonosis caused by species of the genetically homogenous genus Brucella. As in most studies on bacterial diseases, research in brucellosis is carried out by using reference strains as canonical models to understand the mechanisms underlying host pathogen interactions. We performed whole genome sequencing analysis of the reference strain B. abortus 2308 routinely used in our laboratory, including manual curated annotation accessible as an editable version through a link at https://en.wikipedia.org/wiki/Brucella#Genomics. Comparison of this genome with two publically available 2308 genomes showed significant differences, particularly indels related to insertional elements, suggesting variability related to the transposition of these elements within the same strain. Considering the outcome of high resolution genomic techniques in the bacteriology field, the conventional concept of strain definition needs to be revised.
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Affiliation(s)
- Marcela Suárez-Esquivel
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica Heredia, Costa Rica
| | - Nazareth Ruiz-Villalobos
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica Heredia, Costa Rica
| | - Amanda Castillo-Zeledón
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica Heredia, Costa Rica
| | - César Jiménez-Rojas
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica Heredia, Costa Rica
| | - R Martin Roop Ii
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Diego J Comerci
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", Instituto Tecnológico de Chascomús, Universidad Nacional de San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas, Comisión Nacional de Energía Atómica, Grupo Pecuario, Centro Atómico Ezeiza Buenos Aires, Argentina
| | - Elías Barquero-Calvo
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica San José, Costa Rica
| | - Carlos Chacón-Díaz
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa RicaHeredia, Costa Rica; Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa RicaSan José, Costa Rica
| | - Clayton C Caswell
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech Blacksburg, VA, USA
| | - Kate S Baker
- Wellcome Trust Sanger InstituteHinxton, UK; Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of LiverpoolLiverpool, UK
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica San José, Costa Rica
| | - Nicholas R Thomson
- Wellcome Trust Sanger InstituteHinxton, UK; The London School of Hygiene and Tropical MedicineLondon, UK
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa RicaHeredia, Costa Rica; Instituto Clodomiro Picado, Universidad de Costa RicaSan José, Costa Rica
| | - Jean J Letesson
- Unité de Recherche en Biologie des Microorganismes, Université de Namur Namur Belgium
| | - Xavier De Bolle
- Unité de Recherche en Biologie des Microorganismes, Université de Namur Namur Belgium
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa RicaHeredia, Costa Rica; Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa RicaSan José, Costa Rica
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Ducrotoy MJ, Conde-Álvarez R, Blasco JM, Moriyón I. A review of the basis of the immunological diagnosis of ruminant brucellosis. Vet Immunol Immunopathol 2016; 171:81-102. [DOI: 10.1016/j.vetimm.2016.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/07/2016] [Accepted: 02/02/2016] [Indexed: 01/18/2023]
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Fontana C, Conde-Álvarez R, Ståhle J, Holst O, Iriarte M, Zhao Y, Arce-Gorvel V, Hanniffy S, Gorvel JP, Moriyón I, Widmalm G. Structural Studies of Lipopolysaccharide-defective Mutants from Brucella melitensis Identify a Core Oligosaccharide Critical in Virulence. J Biol Chem 2016; 291:7727-41. [PMID: 26867577 PMCID: PMC4817197 DOI: 10.1074/jbc.m115.701540] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Indexed: 11/07/2022] Open
Abstract
The structures of the lipooligosaccharides from Brucella melitensis mutants affected in the WbkD and ManBcore proteins have been fully characterized using NMR spectroscopy. The results revealed that disruption of wbkD gives rise to a rough lipopolysaccharide (R-LPS) with a complete core structure (β-d-Glcp-(1→4)-α-Kdop-(2→4)[β-d-GlcpN-(1→6)-β-d-GlcpN-(1→4)[β-d-GlcpN-(1→6)]-β-d-GlcpN-(1→3)-α-d-Manp-(1→5)]-α-Kdop-(2→6)-β-d-GlcpN3N4P-(1→6)-α-d-GlcpN3N1P), in addition to components lacking one of the terminal β-d-GlcpN and/or the β-d-Glcp residues (48 and 17%, respectively). These structures were identical to those of the R-LPS from B. melitensis EP, a strain simultaneously expressing both smooth and R-LPS, also studied herein. In contrast, disruption of manBcore gives rise to a deep-rough pentasaccharide core (β-d-Glcp-(1→4)-α-Kdop-(2→4)-α-Kdop-(2→6)-β-d-GlcpN3N4P-(1→6)-α-d-GlcpN3N1P) as the major component (63%), as well as a minor tetrasaccharide component lacking the terminal β-d-Glcp residue (37%). These results are in agreement with the predicted functions of the WbkD (glycosyltransferase involved in the biosynthesis of the O-antigen) and ManBcore proteins (phosphomannomutase involved in the biosynthesis of a mannosyl precursor needed for the biosynthesis of the core and O-antigen). We also report that deletion of B. melitensis wadC removes the core oligosaccharide branch not linked to the O-antigen causing an increase in overall negative charge of the remaining LPS inner section. This is in agreement with the mannosyltransferase role predicted for WadC and the lack of GlcpN residues in the defective core oligosaccharide. Despite carrying the O-antigen essential in B. melitensis virulence, the core deficiency in the wadC mutant structure resulted in a more efficient detection by innate immunity and attenuation, proving the role of the β-d-GlcpN-(1→6)-β-d-GlcpN-(1→4)[β-d-GlcpN-(1→6)]-β-d-GlcpN-(1→3)-α-d-Manp-(1→5) structure in virulence.
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Affiliation(s)
- Carolina Fontana
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Raquel Conde-Álvarez
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Jonas Ståhle
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Otto Holst
- the Division of Structural Biochemistry, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma and Allergy, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research, D-23845 Borstel, Germany
| | - Maite Iriarte
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Yun Zhao
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France
| | - Vilma Arce-Gorvel
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Seán Hanniffy
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Jean-Pierre Gorvel
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Ignacio Moriyón
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Göran Widmalm
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden,
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The Complete Genome of Brucella Suis 019 Provides Insights on Cross-Species Infection. Genes (Basel) 2016; 7:genes7020007. [PMID: 26821047 PMCID: PMC4773751 DOI: 10.3390/genes7020007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/13/2016] [Accepted: 01/19/2016] [Indexed: 11/21/2022] Open
Abstract
Brucella species are the most important zoonotic pathogens worldwide and cause considerable harm to humans and animals. In this study, we presented the complete genome of B. suis 019 isolated from sheep (ovine) with epididymitis. B. suis 019 has a rough phenotype and can infect sheep, rhesus monkeys and possibly humans. The comparative genome analysis demonstrated that B. suis 019 is closest to the vaccine strain B. suis bv. 1 str. S2. Further analysis associated the rsh gene to the pathogenicity of B. suis 019, and the WbkA gene to the rough phenotype of B. suis 019. The 019 complete genome data was deposited in the GenBank database with ID PRJNA308608.
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Mancilla M. Smooth to Rough Dissociation in Brucella: The Missing Link to Virulence. Front Cell Infect Microbiol 2016; 5:98. [PMID: 26779449 PMCID: PMC4700419 DOI: 10.3389/fcimb.2015.00098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/10/2015] [Indexed: 11/24/2022] Open
Abstract
Dissociation encompasses changes in a series of phenotypes: colony and cell morphology, inmunological and biochemical reactions and virulence. The concept is generally associated to the in vitro transition between smooth (S) and rough (R) colonies, a phenotypic observation in Gram-negative bacteria commonly made since the beginning of microbiology as a science. It is also well known that the loss of the O-polysaccharide, the most external lipopolysaccharide (LPS) moiety, triggers the change in the colony phenotype. Although dissociation is related to one of the most basic features used to distinguish between species, i.e., colony morphology, and, in the case of pathogens, predict their virulence behavior, it has been considered a laboratory artifact and thus did not gain further attention. However, recent insights into genetics and pathogenesis of members of Brucella, causative agents of brucellosis, have brought a new outlook on this experimental fact, suggesting that it plays a role beyond the laboratory observations. In this perspective article, the current knowledge on Brucella LPS genetics and its connection with dissociation in the frame of evolution is discussed. Latest reports support the notion that, by means of a better understanding of genetic pathways linked to R phenotype and the biological impact of this intriguing "old" phenomenon, unexpected applications can be achieved.
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Affiliation(s)
- Marcos Mancilla
- Research and Development Department, ADL Diagnostic Chile Ltd.Puerto Montt, Chile
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Phenotypic and genotypic characterization of Brucella strains isolated from autochthonous livestock reveals the dominance of B. abortus biovar 3a in Nigeria. Vet Microbiol 2015; 180:103-8. [DOI: 10.1016/j.vetmic.2015.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/30/2015] [Accepted: 08/14/2015] [Indexed: 12/31/2022]
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Pei J, Kahl-McDonagh M, Ficht TA. Brucella dissociation is essential for macrophage egress and bacterial dissemination. Front Cell Infect Microbiol 2014; 4:23. [PMID: 24634889 PMCID: PMC3942807 DOI: 10.3389/fcimb.2014.00023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 02/10/2014] [Indexed: 12/24/2022] Open
Abstract
It has long been observed that smooth Brucella can dissociate into rough mutants that are cytotoxic to macrophages. However, the in vivo biological significance and/or mechanistic details of Brucella dissociation and cytotoxicity remain incomplete. In the current report, a plaque assay was developed using Brucella strains exhibiting varying degrees of cytotoxicity. Infected monolayers were observed daily using phase contrast microscopy for plaque formation while Brucella uptake and replication were monitored using an immunofluorescence assay (IFA). Visible plaques were detected at 4-5 days post infection (p.i.) with cytotoxic Brucella 16MΔmanBA at an MOI of 0.1. IFA staining demonstrated that the plaques consisted of macrophages with replicating Brucella. Visible plaques were not detected in monolayers infected with non-cytotoxic 16MΔmanBAΔvirB2 at an MOI of 0.1. However, IFA staining did reveal small groups of macrophages (foci) with replicating Brucella in the monolayers infected with 16MΔmanBAΔvirB2. The size of the foci observed in macrophage monolayers infected with rough Brucella correlated directly with cytotoxicity measured in liquid culture, suggesting that cytotoxicity was essential for Brucella egress and dissemination. In monolayers infected with 16M, small and large foci were observed. Double antibody staining revealed spontaneous rough mutants within the large, but not the small foci in 16M infected monolayers. Furthermore, plaque formation was observed in the large foci derived from 16M infections. Finally, the addition of gentamicin to the culture medium inhibited plaque formation, suggesting that cell-to-cell spread occurred only following release of the organisms from the cells. Taken together, these results demonstrate that Brucella-induced cytotoxicity is critical for Brucella egress and dissemination.
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Affiliation(s)
| | | | - Thomas A. Ficht
- Department of Veterinary Pathobiology, Texas A&M University and Texas Agricultural Experiment StationCollege Station, TX, USA
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Mancilla M, Grilló MJ, de Miguel MJ, López-Goñi I, San-Román B, Zabalza-Baranguá A, Moriyón I. Deletion of the GI-2 integrase and the wbkA flanking transposase improves the stability of Brucella melitensis Rev 1 vaccine. Vet Res 2013; 44:105. [PMID: 24176078 PMCID: PMC4176087 DOI: 10.1186/1297-9716-44-105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 10/21/2013] [Indexed: 12/17/2022] Open
Abstract
Brucella melitensis Rev 1 is the best vaccine available for the prophylaxis of small ruminant brucellosis and, indirectly, for reducing human brucellosis. However, Rev 1 shows anomalously high rates of spontaneous dissociation from smooth (S) to rough (R) bacteria, the latter being inefficacious as vaccines. This S-R instability results from the loss of the O-polysaccharide. To overcome this problem, we investigated whether some recently described mechanisms promoting mutations in O-polysaccharide genes were involved in Rev 1 S-R dissociation. We found that a proportion of Rev 1 R mutants result from genome rearrangements affecting the wbo O-polysaccharide loci of genomic island GI-2 and the wbkA O-polysaccharide glycosyltransferase gene of the wbk region. Accordingly, we mutated the GI-2 int gene and the wbk IS transposase involved in those arrangements, and found that these Rev 1 mutants maintained the S phenotype and showed lower dissociation levels. Combining these two mutations resulted in a strain (Rev 2) displaying a 95% decrease in dissociation with respect to parental Rev 1 under conditions promoting dissociation. Rev 2 did not differ from Rev 1 in the characteristics used in Rev 1 typing (growth rate, colonial size, reactivity with O-polysaccharide antibodies, phage, dye and antibiotic susceptibility). Moreover, Rev 2 and Rev 1 showed similar attenuation and afforded similar protection in the mouse model of brucellosis vaccines. We conclude that mutations targeting genes and DNA sequences involved in spontaneous O-polysaccharide loss enhance the stability of a critical vaccine phenotype and complement the empirical stabilization precautions taken during S Brucella vaccine production.
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Affiliation(s)
- Marcos Mancilla
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, C/ Irunlarrea, 1, 31008 Pamplona, Spain
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Campus Isla Teja, casilla 567, Valdivia, Chile
| | - María-Jesús Grilló
- Grupo de Sanidad Animal, Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Campus de Arrosadía, 31006 Pamplona, Spain
| | - María-Jesús de Miguel
- Unidad de Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Gobierno de Aragón. Av. Montañana, 930, 50059 Zaragoza, Spain
| | - Ignacio López-Goñi
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, C/ Irunlarrea, 1, 31008 Pamplona, Spain
| | - Beatriz San-Román
- Grupo de Sanidad Animal, Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Campus de Arrosadía, 31006 Pamplona, Spain
| | - Ana Zabalza-Baranguá
- Grupo de Sanidad Animal, Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Campus de Arrosadía, 31006 Pamplona, Spain
| | - Ignacio Moriyón
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, C/ Irunlarrea, 1, 31008 Pamplona, Spain
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