1
|
Zhang G, Dong H, Feng Y, Jiang H, Wu T, Sun J, Wang X, Liu M, Peng X, Zhang Y, Zhang X, Zhu L, Ding J, Shen X. The Pseudogene BMEA_B0173 Deficiency in Brucella melitensis Contributes to M-epitope Formation and Potentiates Virulence in a Mice Infection Model. Curr Microbiol 2022; 79:378. [DOI: 10.1007/s00284-022-03078-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
|
2
|
Tian M, Li Z, Qu J, Fang T, Yin Y, Zuo D, Abdelgawad HA, Hu H, Wang S, Qi J, Wang G, Yu S. The novel LysR-family transcriptional regulator BvtR is involved in the resistance of Brucella abortus to nitrosative stress, detergents and virulence through the genetic regulation of diverse pathways. Vet Microbiol 2022; 267:109393. [PMID: 35259600 DOI: 10.1016/j.vetmic.2022.109393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/22/2022] [Accepted: 02/28/2022] [Indexed: 11/22/2022]
Abstract
Brucella is a facultative intracellular bacterium lacking classical virulence factors; its virulence instead depends on its ability to invade and proliferate within host cells. After entering cells, Brucella rapidly modulates the expression of a series of genes involved in metabolism and immune evasion. Here, a novel LysR-family transcriptional regulator, designated Brucellavirulence-related transcriptional regulator (BvtR), was found to be associated with Brucella abortus virulence. We first successfully constructed a BvtR mutant, ΔbvtR, and a complemented strain, ΔbvtR-Com. Subsequently, we performed cell infection experiments, which indicated that the ΔbvtR strain exhibited similar adhesion, invasion and survival within HeLa cells or RAW264.7 macrophages to those of the wild-type strain. In stress resistance tests, the ΔbvtR strain showed enhanced sensitivity to sodium nitroprusside and sodium dodecyl sulfate, but not to hydrogen peroxide, cumene hydroperoxide, polymyxin B and natural serum. Mouse infection experiments indicated that the virulence of the ΔbvtR strain significantly decreased at 4 weeks post-infection. Finally, we analyzed differentially expressed genes regulated by BvtR with RNA-seq, COG classification and KEGG pathway analysis. Nitrogen metabolism, siderophore biosynthesis and oligopeptide transport were found to be the predominantly altered functions, and key metabolic and regulatory networks were delineated in the ΔbvtR mutant. Thus, we identified a novel Brucella virulence-related regulator, BvtR, and demonstrated that BvtR regulation affects Brucella resistance to killing by sodium nitroprusside and sodium dodecyl sulfate. The differentially expressed genes responding to BvtR are involved in diverse functions or pathways in Brucella, thus, suggesting the breadth of BvtR's regulatory functions. This study provides novel clues regarding Brucella pathogenesis.
Collapse
Affiliation(s)
- Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Zichen Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jing Qu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; Songjiang District Center for Animal Disease Control and Prevention, Shanghai 201699, China
| | - Tian Fang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Yi Yin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Dong Zuo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hosny Ahmed Abdelgawad
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Guijun Wang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China.
| |
Collapse
|
3
|
Roop RM, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev 2021; 85:e00021-19. [PMID: 33568459 PMCID: PMC8549849 DOI: 10.1128/mmbr.00021-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.
Collapse
Affiliation(s)
- R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ian S Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Dariel Hopersberger
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Daniel W Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| |
Collapse
|
4
|
Banerjee S, Garrigues RJ, Chanakira MN, Negron-Olivo JJ, Odeh YH, Spuches AM, Martin Roop R, Pitzer JE, Martin DW, Dasgupta S. Investigating the roles of the conserved Cu 2+-binding residues on Brucella FtrA in producing conformational stability and functionality. J Inorg Biochem 2020; 210:111162. [PMID: 32623149 PMCID: PMC7484176 DOI: 10.1016/j.jinorgbio.2020.111162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/07/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022]
Abstract
Brucella is a zoonotic pathogen requiring iron for its survival and acquires this metal through the expression of several high-affinity uptake systems. Of these, the newly discovered ferrous iron transporter, FtrABCD, is proposed to take part in ferrous iron uptake. Sequence homology shows that, FtrA, the proposed periplasmic ferrous-binding component, is a P19-type protein (a periplasmic protein from C. jejuni which shows Cu2+ dependent iron affinity). Previous structural and biochemical studies on other P19 systems have established a Cu2+ dependent Mn2+ affinity as well as formation of homodimers for these systems. The Cu2+ coordinating amino acids from these proteins are conserved in Brucella FtrA, hinting towards similar properties. However, there has been no experimental evidence, till date, establishing metal affinities and the possibility of dimer formation by Brucella FtrA. Using wild-type FtrA and Cu2+-binding mutants (H65A, E67A, H118A, and H151A) we investigated the metal affinities, folding stabilities, dimer forming abilities, and the molecular basis of the Cu2+ dependence for this P19-type protein employing homology modeling, analytical gel filtration, calorimetric, and spectroscopic methods. The data reported here confirm a Cu2+-dependent, low-μM Mn2+ (Fe2+ mimic) affinity for the wild-type FtrA. In addition, our data clearly show the loss of Mn2+ affinity, and the formation of less stable protein conformations as a result of mutating these conserved Cu2+-binding residues, indicating the important roles these residues play in producing a native and functional fold of Brucella FtrA.
Collapse
Affiliation(s)
- Sambuddha Banerjee
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA.
| | - Ryan J Garrigues
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Mina N Chanakira
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | | | - Yasmene H Odeh
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Anne M Spuches
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Joshua Edison Pitzer
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Daniel W Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Saumya Dasgupta
- Department of Chemistry, Amity Institute of Applied Sciences, Amity University Kolkata, WB, 700135, India
| |
Collapse
|
5
|
Sidhu-Muñoz RS, Tejedor C, Vizcaíno N. The Three Flagellar Loci of Brucella ovis PA Are Dispensable for Virulence in Cellular Models and Mice. Front Vet Sci 2020; 7:441. [PMID: 32851024 PMCID: PMC7410920 DOI: 10.3389/fvets.2020.00441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 06/18/2020] [Indexed: 12/22/2022] Open
Abstract
Brucella ovis is a facultative intracellular bacterium that causes a non-zoonotic ovine brucellosis mainly characterized by male genital lesions and is responsible for important economic losses in sheep farming areas. Studies about the virulence mechanisms of Brucella have been mostly performed with smooth (bearing O-polysaccharide in lipopolysaccharide) zoonotic species, and those performed with B. ovis have revealed similarities but also relevant differences. Except for few strains recently isolated from unconventional hosts, Brucella species are non-motile but contain the genes required to assemble a flagellum, which are organized in three main loci of about 18.5, 6.4, and 7.8 kb. Although these loci contain different pseudogenes depending on the non-motile Brucella species, smooth B. melitensis 16M builds a sheathed flagellum under particular culture conditions and requires flagellar genes for virulence. However, nothing is known in this respect regarding other Brucella strains. In this work, we have constructed a panel of B. ovis PA mutants defective in one, two or the three flagellar loci in order to assess their role in virulence of this rough (lacking O-polysaccharide) Brucella species. No relevant differences in growth, outer membrane-related properties or intracellular behavior in cellular models were observed between flagellar mutants and the parental strain, which is in accordance with previous results with B. melitensis 16M single-gene mutants. However, contrary to these B. melitensis mutants, unable to establish a chronic infection in mice, removal of the three flagellar loci in B. ovis did not affect virulence in the mouse model. These results evidence new relevant differences between B. ovis and B. melitensis, two species highly homologous at the DNA level and that cause ovine brucellosis, but that exhibit differences in the zoonotic potential, pathogenicity and tissue tropism.
Collapse
Affiliation(s)
- Rebeca S Sidhu-Muñoz
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Carmen Tejedor
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Nieves Vizcaíno
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| |
Collapse
|
6
|
Sidhu-Muñoz RS, Sancho P, Cloeckaert A, Zygmunt MS, de Miguel MJ, Tejedor C, Vizcaíno N. Characterization of Cell Envelope Multiple Mutants of Brucella ovis and Assessment in Mice of Their Vaccine Potential. Front Microbiol 2018; 9:2230. [PMID: 30294312 PMCID: PMC6158377 DOI: 10.3389/fmicb.2018.02230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/31/2018] [Indexed: 01/22/2023] Open
Abstract
Brucella ovis is a non-zoonotic Brucella species lacking specific vaccine. It presents a narrow host range, a unique biology relative to other Brucella species, and important distinct surface properties. To increase our knowledge on its peculiar surface and virulence features, and seeking to develop a specific vaccine, multiple mutants for nine relevant cell-envelope-related genes were investigated. Mutants lacking Omp10 plus Omp19 could not be obtained, suggesting that at least one of these lipoproteins is required for viability. A similar result was obtained for the double deletion of omp31 and omp25 that encode two major surface proteins. Conversely, the absence of major Omp25c (proved essential for internalization in HeLa cells) together with Omp25 or Omp31 was tolerated by the bacterium. Although showing important in vitro and in vivo defects, the Δomp10Δomp31Δomp25c mutant was obtained, demonstrating that B. ovis PA survives to the simultaneous absence of Omp10 and four out seven proteins of the Omp25/Omp31 family (i.e., Omp31, Omp25c, Omp25b, and Omp31b, the two latter naturally absent in B. ovis). Three multiple mutants were selected for a detailed analysis of virulence in the mouse model. The Δomp31Δcgs and Δomp10Δomp31Δomp25c mutants were highly attenuated when inoculated at 106 colony forming units/mouse but they established a persistent infection when the infection dose was increased 100-fold. The Δomp10ΔugpBΔomp31 mutant showed a similar behavior until week 3 post-infection but was then totally cleared from spleen. Accordingly, it was retained as vaccine candidate for mice protection assays. When compared to classical B. melitensis Rev1 heterologous vaccine, the triple mutant induced limited splenomegaly, a significantly higher antibody response against whole B. ovis PA cells, an equivalent memory cellular response and, according to spleen colonization measurements, better protection against a challenge with virulent B. ovis PA. Therefore, it would be a good candidate to be evaluated in the natural host as a specific vaccine against B. ovis that would avoid the drawbacks of B. melitensis Rev1. In addition, the lack in this attenuated strain of Omp31, recognized as a highly immunogenic protein during B. ovis infection, would favor the differentiation between infected and vaccinated animals using Omp31 as diagnostic target.
Collapse
Affiliation(s)
- Rebeca Singh Sidhu-Muñoz
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
| | - Pilar Sancho
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Axel Cloeckaert
- Plasticité Génomique, Biodiversité, Antibiorésistance (PGBA), UR1282 - Infectiologie Animale, Santé Publique (IASP-311), Institut National de la Recherche Agronomique Centre Val de Loire, Nouzilly, France
| | - Michel Stanislas Zygmunt
- Plasticité Génomique, Biodiversité, Antibiorésistance (PGBA), UR1282 - Infectiologie Animale, Santé Publique (IASP-311), Institut National de la Recherche Agronomique Centre Val de Loire, Nouzilly, France
| | - María Jesús de Miguel
- Unidad de Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón - IA2, Zaragoza, Spain
| | - Carmen Tejedor
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Nieves Vizcaíno
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
| |
Collapse
|
7
|
Salmon-Divon M, Yeheskel A, Kornspan D. Genomic analysis of the original Elberg Brucella melitensis Rev.1 vaccine strain reveals insights into virulence attenuation. Virulence 2018; 9:1436-1448. [PMID: 30139304 PMCID: PMC6141144 DOI: 10.1080/21505594.2018.1511677] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/06/2018] [Indexed: 11/30/2022] Open
Abstract
The live attenuated Brucella melitensis Rev.1 Elberg-originated vaccine strain has been widely used to control brucellosis in small ruminants. However, despite extensive research, the molecular mechanisms underlying the attenuation of this strain are still unknown. In the current study, we conducted a comprehensive comparative analysis of the whole-genome sequence of Rev.1 against that of the virulent reference strain, B. melitensis 16M. This analysis revealed five regions of insertion and three regions of deletion within the Rev.1 genome, among which, one large region of insertion, comprising 3,951 bp, was detected in the Rev.1 genome. In addition, we found several missense mutations within important virulence-related genes, which may be used to determine the mechanism underlying virulence attenuation. Collectively, our findings provide new insights into the Brucella virulence mechanisms and, therefore, may serve as a basis for the rational design of new Brucella vaccines.
Collapse
Affiliation(s)
- Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel, Israel
| | - Adva Yeheskel
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel
| |
Collapse
|
8
|
Nas MY, Cianciotto NP. Stenotrophomonas maltophilia produces an EntC-dependent catecholate siderophore that is distinct from enterobactin. MICROBIOLOGY-SGM 2017; 163:1590-1603. [PMID: 28984234 DOI: 10.1099/mic.0.000545] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Stenotrophomonas maltophilia, a Gram-negative, multi-drug-resistant bacterium, is increasingly recognized as a key opportunistic pathogen. Thus, we embarked upon an investigation of S. maltophilia iron acquisition. To begin, we determined that the genome of strain K279a is predicted to encode a complete siderophore system, including a biosynthesis pathway, an outer-membrane receptor for ferrisiderophore, and other import and export machinery. Compatible with these data, K279a and other clinical isolates of S. maltophilia secreted a siderophore-like activity when grown at 25-37 °C in low-iron media, as demonstrated by a chrome azurol S assay, which detects iron chelation, and Arnow and Rioux assays, which detect catecholate structures. Importantly, these supernatants rescued the growth of iron-starved S. maltophilia, documenting the presence of a biologically active siderophore. A mutation in one of the predicted biosynthesis genes (entC) abolished production of the siderophore and impaired bacterial growth in low-iron conditions. Inactivation of the putative receptor gene (fepA) prevented the utilization of siderophore-containing supernatants for growth in low-iron conditions. Although the biosynthesis and import loci showed some similarity to those of enterobactin, a well-known catecholate made by enteric bacteria, the siderophore of K279a was unable to rescue the growth of an enterobactin-utilizing indicator strain, and conversely iron-starved S. maltophilia could not use purified enterobactin. Furthermore, the S. maltophilia siderophore displayed patterns of solubility in organic compounds and mobility upon thin-layer chromatography that were distinct from those of enterobactin and its derivative, salmochelin. Together, these data demonstrate that S. maltophilia secretes a novel catecholate siderophore.
Collapse
Affiliation(s)
- Megan Y Nas
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| |
Collapse
|
9
|
Caudill MT, Budnick JA, Sheehan LM, Lehman CR, Purwantini E, Mukhopadhyay B, Caswell CC. Proline utilization system is required for infection by the pathogenic α-proteobacterium Brucella abortus. MICROBIOLOGY-SGM 2017; 163:970-979. [PMID: 28691659 DOI: 10.1099/mic.0.000490] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Proline utilization (Put) systems have been described in a number of bacteria; however, the importance and functionality of the Put system in the intracellular pathogen Brucellaabortus has not been explored. Generally, bacterial Put systems are composed of the bifunctional enzyme proline dehydrogenase PutA and its transcriptional activator PutR. Here, we demonstrate that the genes putA (bab2_0518) and putR (bab2_0517) are critical for the chronic infection of mice by B. abortus, but putA and putR are not required for the survival and replication of the bacteria in naive macrophages. Additionally, in vitro experiments revealed that putR is necessary for the ability of the bacteria to withstand oxidative stress, as a ΔputR deletion strain is hypersensitive to hydrogen peroxide exposure. Quantitative reverse transcription-PCR and putA-lacZ transcriptional reporter studies revealed that PutR acts as a transcriptional activator of putA in Brucella, and electrophoretic mobility shift assays confirmed that PutR binds directly to the putA promoter region. Biochemical analyses demonstrated that a purified recombinant B. abortus PutA protein possesses quintessential proline dehydrogenase activity, as PutA is capable of catalysing the conversion of proline to glutamate. Altogether, these data are the first to reveal that the Put system plays a significant role in the ability of B. abortus to replicate and survive within its host, as well as to describe the genetic regulation and biochemical activity of the Put system in Brucella.
Collapse
Affiliation(s)
- Mitchell T Caudill
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
| | - James A Budnick
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
| | - Lauren M Sheehan
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
| | - Christian R Lehman
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
| | - Endang Purwantini
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Clayton C Caswell
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
| |
Collapse
|
10
|
Abstract
Brucellosis, caused by bacteria of the genus Brucella, is an important zoonotic infection that causes reproductive disease in domestic animals and chronic debilitating disease in humans. An intriguing aspect of Brucella infection is the ability of these bacteria to evade the host immune response, leading to pathogen persistence. Conversely, in the reproductive tract of infected animals, this stealthy pathogen is able to cause an acute severe inflammatory response. In this review, we discuss the different mechanisms used by Brucella to cause disease, with emphasis on its virulence factors and the dichotomy between chronic persistence and reproductive disease.
Collapse
Affiliation(s)
| | - Renee M Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, California 95616; ,
| |
Collapse
|
11
|
Liu Q, Liu X, Yan F, He Y, Wei J, Zhang Y, Liu L, Sun Y. Comparative transcriptome analysis of Brucella melitensis in an acidic environment: Identification of the two-component response regulator involved in the acid resistance and virulence of Brucella. Microb Pathog 2015; 91:92-8. [PMID: 26691825 DOI: 10.1016/j.micpath.2015.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/06/2015] [Accepted: 11/09/2015] [Indexed: 01/01/2023]
Abstract
Brucella melitensis, encounters a very stressful environment in phagosomes, especially low pH levels. So identifying the genes that contribute to the replication and survival within an acidic environment is critical in understanding the pathogenesis of the Brucella bacteria. In our research, comparative transcriptome with RNA-seq were used to analyze the changes of genes in normal-medium culture and in pH4.4-medium culture. The results reveal that 113 genes expressed with significant differences (|log2Ratio| ≥ 3); about 44% genes expressed as up-regulated. With GO term analysis, structural constituent of the ribosome, rRNA binding, structural molecule activity, and cation-transporting ATPase activity were significantly enriched (p-value ≤ 0.05). These genes distributed in 51 pathways, in which ribosome and photosynthesis pathways were significantly enriched. Six pathways (oxidative phosphorylation, iron-transporting, bacterial secretion system, transcriptional regulation, two-component system, and ABC transporters pathways) tightly related to the intracellular survival and virulence of Brucella were analyzed. A two-component response regulator gene in the transcriptional regulation pathway, identified through gene deletion and complementary technologies, played an important role in the resistance to the acid-resistance and virulence of Brucella.
Collapse
Affiliation(s)
- Qianhong Liu
- Jilin Agricultural Science and Technology University, Jilin 132101, China.
| | - Xingyu Liu
- Guangzhou Airport Entry-Exit Inspection and Quarantine Brueau of P.R.C, Guangzhou 510470, China
| | - Feng Yan
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Yuhua He
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Jie Wei
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Yuanyuan Zhang
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Lu Liu
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Youpeng Sun
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| |
Collapse
|
12
|
Wu T, Wang S, Wang Z, Peng X, Lu Y, Wu Q. A multicopper oxidase contributes to the copper tolerance of Brucella melitensis 16M. FEMS Microbiol Lett 2015; 362:fnv078. [DOI: 10.1093/femsle/fnv078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2015] [Indexed: 12/22/2022] Open
|
13
|
Peng X, Dong H, Wu Q. A new cis-encoded sRNA, BsrH, regulating the expression of hemH gene in Brucella abortus 2308. FEMS Microbiol Lett 2014; 362:1-7. [DOI: 10.1093/femsle/fnu017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
|
14
|
Atlas of nonribosomal peptide and polyketide biosynthetic pathways reveals common occurrence of nonmodular enzymes. Proc Natl Acad Sci U S A 2014; 111:9259-64. [PMID: 24927540 DOI: 10.1073/pnas.1401734111] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Nonribosomal peptides and polyketides are a diverse group of natural products with complex chemical structures and enormous pharmaceutical potential. They are synthesized on modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) enzyme complexes by a conserved thiotemplate mechanism. Here, we report the widespread occurrence of NRPS and PKS genetic machinery across the three domains of life with the discovery of 3,339 gene clusters from 991 organisms, by examining a total of 2,699 genomes. These gene clusters display extraordinarily diverse organizations, and a total of 1,147 hybrid NRPS/PKS clusters were found. Surprisingly, 10% of bacterial gene clusters lacked modular organization, and instead catalytic domains were mostly encoded as separate proteins. The finding of common occurrence of nonmodular NRPS differs substantially from the current classification. Sequence analysis indicates that the evolution of NRPS machineries was driven by a combination of common descent and horizontal gene transfer. We identified related siderophore NRPS gene clusters that encoded modular and nonmodular NRPS enzymes organized in a gradient. A higher frequency of the NRPS and PKS gene clusters was detected from bacteria compared with archaea or eukarya. They commonly occurred in the phyla of Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria in bacteria and the phylum of Ascomycota in fungi. The majority of these NRPS and PKS gene clusters have unknown end products highlighting the power of genome mining in identifying novel genetic machinery for the biosynthesis of secondary metabolites.
Collapse
|
15
|
Wattam AR, Foster JT, Mane SP, Beckstrom-Sternberg SM, Beckstrom-Sternberg JM, Dickerman AW, Keim P, Pearson T, Shukla M, Ward DV, Williams KP, Sobral BW, Tsolis RM, Whatmore AM, O'Callaghan D. Comparative phylogenomics and evolution of the Brucellae reveal a path to virulence. J Bacteriol 2014; 196:920-30. [PMID: 24336939 PMCID: PMC3957692 DOI: 10.1128/jb.01091-13] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/04/2013] [Indexed: 11/20/2022] Open
Abstract
Brucella species include important zoonotic pathogens that have a substantial impact on both agriculture and human health throughout the world. Brucellae are thought of as "stealth pathogens" that escape recognition by the host innate immune response, modulate the acquired immune response, and evade intracellular destruction. We analyzed the genome sequences of members of the family Brucellaceae to assess its evolutionary history from likely free-living soil-based progenitors into highly successful intracellular pathogens. Phylogenetic analysis split the genus into two groups: recently identified and early-dividing "atypical" strains and a highly conserved "classical" core clade containing the major pathogenic species. Lateral gene transfer events brought unique genomic regions into Brucella that differentiated them from Ochrobactrum and allowed the stepwise acquisition of virulence factors that include a type IV secretion system, a perosamine-based O antigen, and systems for sequestering metal ions that are absent in progenitors. Subsequent radiation within the core Brucella resulted in lineages that appear to have evolved within their preferred mammalian hosts, restricting their virulence to become stealth pathogens capable of causing long-term chronic infections.
Collapse
Affiliation(s)
- Alice R. Wattam
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Jeffrey T. Foster
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
| | | | - Stephen M. Beckstrom-Sternberg
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - James M. Beckstrom-Sternberg
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - Allan W. Dickerman
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Paul Keim
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - Talima Pearson
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
| | - Maulik Shukla
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Doyle V. Ward
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Kelly P. Williams
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Bruno W. Sobral
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Renee M. Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, California, USA
| | - Adrian M. Whatmore
- Department of Bacteriology, Animal Health & Veterinary Laboratories Agency, Addlestone, United Kingdom
| | - David O'Callaghan
- INSERM U1047, UFR Médecine, Nîmes, France
- Université Montpellier 1, UFR Médecine, Nîmes, France
| |
Collapse
|
16
|
Wang Z, Wang SS, Wang GL, Wu TL, Lv YL, Wu QM. A pregnant mouse model for the vertical transmission of Brucella melitensis. Vet J 2013; 200:116-21. [PMID: 24462801 DOI: 10.1016/j.tvjl.2013.12.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 12/10/2013] [Accepted: 12/19/2013] [Indexed: 11/24/2022]
Abstract
Abortion is the major clinical sign of brucellosis in animals but little is known about the underlying mechanisms. This study was designed to evaluate a pregnant mouse model for the vertical transmission of Brucella melitensis using four infectious doses: 10(3) colony-forming units (CFU), 10(4) CFU, 10(5) CFU, and 10(6) CFU. During the experimental period, no instances of abortion were recorded, but stillbirths were observed in the groups infected with doses of 10(4) CFU and higher. Regardless of whether the fetuses were stillborn or alive, transmission of bacteria to the fetus and bacterial replication in the cytoplasm of placental trophoblast giant cells were detected. A higher degree of bacterial colonization was found in the placenta than in the spleen or fetus. Doses of 10(5) CFU of B. melitensis or higher produced a severe, necrotizing placentitis similar to the pathological damage observed in ruminants. The data suggest that experimental murine brucellosis resembles ruminant brucellosis and represents a potential model for studying the pathogenic mechanisms of B. melitensis.
Collapse
Affiliation(s)
- Z Wang
- Key Laboratory of Animal Epidemiology and Zoonosis of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan Xilu No. 2, Haidian District, Beijing 100193, China
| | - S S Wang
- College of Biological Sciences, Anyang Institute of Technology, Anyang 455000, China
| | - G L Wang
- College of Veterinary Medicine, Qinghai University, Xining 810000, China
| | - T L Wu
- Key Laboratory of Animal Epidemiology and Zoonosis of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan Xilu No. 2, Haidian District, Beijing 100193, China
| | - Y L Lv
- Key Laboratory of Animal Epidemiology and Zoonosis of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan Xilu No. 2, Haidian District, Beijing 100193, China
| | - Q M Wu
- Key Laboratory of Animal Epidemiology and Zoonosis of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan Xilu No. 2, Haidian District, Beijing 100193, China.
| |
Collapse
|
17
|
Jiang H, Du P, Zhang W, Wang H, Zhao H, Piao D, Tian G, Chen C, Cui B. Comparative genomic analysis of Brucella melitensis vaccine strain M5 provides insights into virulence attenuation. PLoS One 2013; 8:e70852. [PMID: 23967122 PMCID: PMC3743847 DOI: 10.1371/journal.pone.0070852] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 06/26/2013] [Indexed: 01/05/2023] Open
Abstract
The Brucella melitensis vaccine strain M5 is widely used to prevent and control brucellosis in animals. In this study, we determined the whole-genome sequence of M5, and conducted a comprehensive comparative analysis against the whole-genome sequence of the virulent strain 16 M and other reference strains. This analysis revealed 11 regions of deletion (RDs) and 2 regions of insertion (RIs) within the M5 genome. Among these regions, the sequences encompassed in 5 RDs and 1 RI showed consistent variation, with a large deletion between the M5 and the 16 M genomes. RD4 and RD5 showed the large diversity among all Brucella genomes, both in RD length and RD copy number. Thus, RD4 and RD5 are potential sites for typing different Brucella strains. Other RD and RI regions exhibited multiple single nucleotide polymorphisms (SNPs). In addition, a genome fragment with a 56 kb rearrangement was determined to be consistent with previous studies. Comparative genomic analysis indicated that genomic island inversion in Brucella was widely present. With the genetic pattern common among all strains analyzed, these 2 RDs, 1 RI, and one inversion region are potential sites for detection of genomic differences. Several SNPs of important virulence-related genes (motB, dhbC, sfuB, dsbAB, aidA, aroC, and lysR) were also detected, and may be used to determine the mechanism of virulence attenuation. Collectively, this study reveals that comparative analysis between wild-type and vaccine strains can provide resources for the study of virulence and microevolution of Brucella.
Collapse
Affiliation(s)
- Hai Jiang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Pengcheng Du
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Wen Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Heng Wang
- Department of Endemic and Parasitic Diseases Control and Prevention, Hangzhou Center for Disease Control and Prevention, Hangzhou, China
| | - Hongyan Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Dongri Piao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Guozhong Tian
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Chen Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
- * E-mail: (CC); (BC)
| | - Buyun Cui
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Beijing, China
- * E-mail: (CC); (BC)
| |
Collapse
|
18
|
Dong H, Liu W, Peng X, Jing Z, Wu Q. The effects of MucR on expression of type IV secretion system, quorum sensing system and stress responses in Brucella melitensis. Vet Microbiol 2013; 166:535-42. [PMID: 23932078 DOI: 10.1016/j.vetmic.2013.06.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 01/21/2023]
Abstract
MucR is a transcriptional regulator in many bacterial pathogens and is required for virulence in mice and macrophages, resistance to stress responses, and modification of the cell envelope in Brucella spp. To determine why the mucR deleted mutant is attenuated in vivo and in vitro, we performed RNA-seq analysis using Brucella melitensis RNA obtained from B. melitensis 16M and 16MΔmucR grown under the same conditions. We found 442 differentially expressed genes; 310 were over expressed, and 132 were less expressed in 16MΔmucR. Many genes identified are involved in metabolism, cell wall/envelope biogenesis, replication, and translation. Notably, genes involved in type IV secretion system and quorum sensing system were down-regulated in 16MΔmucR. In addition, genes involved in tolerance to acid and iron-limitation were also affected and experimentally verified in this study. The effects of MucR on Brucella survival and persistence in mice and macrophages were related to type IV secretion system, quorum sensing system, and stress tolerance, which also provide added insight to the MucR regulon.
Collapse
Affiliation(s)
- Hao Dong
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, PR China
| | | | | | | | | |
Collapse
|
19
|
Elhassanny AEM, Anderson ES, Menscher EA, Roop RM. The ferrous iron transporter FtrABCD is required for the virulence ofBrucella abortus2308 in mice. Mol Microbiol 2013; 88:1070-82. [DOI: 10.1111/mmi.12242] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Ahmed E. M. Elhassanny
- Department of Microbiology and Immunology; East Carolina University School of Medicine; Greenville; NC; 27834; USA
| | - Eric S. Anderson
- Department of Biology; East Carolina University School of Medicine; Greenville; NC; 27858; USA
| | - Evan A. Menscher
- Department of Microbiology and Immunology; East Carolina University School of Medicine; Greenville; NC; 27834; USA
| | - R. Martin Roop
- Department of Microbiology and Immunology; East Carolina University School of Medicine; Greenville; NC; 27834; USA
| |
Collapse
|
20
|
Monocyte-derived macrophages from Zebu (Bos taurus indicus) are more efficient to control Brucella abortus intracellular survival than macrophages from European cattle (Bos taurus taurus). Vet Immunol Immunopathol 2013; 151:294-302. [DOI: 10.1016/j.vetimm.2012.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 12/01/2012] [Accepted: 12/03/2012] [Indexed: 11/24/2022]
|
21
|
Evaluation of the effects of erythritol on gene expression in Brucella abortus. PLoS One 2012; 7:e50876. [PMID: 23272076 PMCID: PMC3522698 DOI: 10.1371/journal.pone.0050876] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/25/2012] [Indexed: 11/19/2022] Open
Abstract
Bacteria of the genus Brucella have the unusual capability to catabolize erythritol and this property has been associated with their virulence mainly because of the presence of erythritol in bovine foetal tissues and because the attenuated S19 vaccine strain is the only Brucella strain unable to oxydize erythritol. In this work we have analyzed the transcriptional changes produced in Brucella by erythritol by means of two high throughput approaches: RNA hybridization against a microarray containing most of Brucella ORF's constructed from the Brucella ORFeome and next generation sequencing of Brucella mRNA in an Illumina GAIIx platform. The results obtained showed the overexpression of a group of genes, many of them in a single cluster around the ery operon, able to co-ordinately mediate the transport and degradation of erythritol into three carbon atoms intermediates that will be then converted into fructose-6P (F6P) by gluconeogenesis. Other induced genes participating in the nonoxidative branch of the pentose phosphate shunt and the TCA may collaborate with the ery genes to conform an efficient degradation of sugars by this route. On the other hand, several routes of amino acid and nucleotide biosynthesis are up-regulated whilst amino acid transport and catabolism genes are down-regulated. These results corroborate previous descriptions indicating that in the presence of erythritol, this sugar was used preferentially over other compounds and provides a neat explanation of the the reported stimulation of growth induced by erythritol.
Collapse
|
22
|
Cain AA, Kosara R, Gibas CJ. GenoSets: visual analytic methods for comparative genomics. PLoS One 2012; 7:e46401. [PMID: 23056299 PMCID: PMC3463605 DOI: 10.1371/journal.pone.0046401] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 09/04/2012] [Indexed: 11/29/2022] Open
Abstract
Many important questions in biology are, fundamentally, comparative, and this extends to our analysis of a growing number of sequenced genomes. Existing genomic analysis tools are often organized around literal views of genomes as linear strings. Even when information is highly condensed, these views grow cumbersome as larger numbers of genomes are added. Data aggregation and summarization methods from the field of visual analytics can provide abstracted comparative views, suitable for sifting large multi-genome datasets to identify critical similarities and differences. We introduce a software system for visual analysis of comparative genomics data. The system automates the process of data integration, and provides the analysis platform to identify and explore features of interest within these large datasets. GenoSets borrows techniques from business intelligence and visual analytics to provide a rich interface of interactive visualizations supported by a multi-dimensional data warehouse. In GenoSets, visual analytic approaches are used to enable querying based on orthology, functional assignment, and taxonomic or user-defined groupings of genomes. GenoSets links this information together with coordinated, interactive visualizations for both detailed and high-level categorical analysis of summarized data. GenoSets has been designed to simplify the exploration of multiple genome datasets and to facilitate reasoning about genomic comparisons. Case examples are included showing the use of this system in the analysis of 12 Brucella genomes. GenoSets software and the case study dataset are freely available at http://genosets.uncc.edu. We demonstrate that the integration of genomic data using a coordinated multiple view approach can simplify the exploration of large comparative genomic data sets, and facilitate reasoning about comparisons and features of interest.
Collapse
Affiliation(s)
- Aurora A. Cain
- Department of Bioinformatics and Genomics, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
| | - Robert Kosara
- Department of Computer Science, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
| | - Cynthia J. Gibas
- Department of Bioinformatics and Genomics, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
| |
Collapse
|
23
|
Effect of exogenous erythritol on growth and survival of Brucella. Vet Microbiol 2012; 160:513-6. [PMID: 22784921 DOI: 10.1016/j.vetmic.2012.06.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 11/21/2022]
Abstract
Erythritol has been considered as an important factor for the pathogenesis of Brucella abortus 2308 and its ability to cause abortion in ruminants. There is a lack of laboratory models to study the Brucella-erythritol relationship, as commonly used murine models do not have erythritol. We tested the effect of exogenous erythritol on the growth of Brucella in iron minimal medium (IMM), in infected macrophage culture and in infected mice to determine if these models can be used to study the relationship between Brucella and erythritol. An effect of erythritol on Brucella growth was only seen in IMM. There appear to be no effect of erythritol on Brucella growth in macrophage cell cultures or in mice. This shows that administration of erythritol to the mice or macrophages cannot mimic the environment in ruminants during pregnancy and thus cannot be used as models to understand the effect of erythritol on Brucella pathogenesis.
Collapse
|
24
|
Abstract
Similar to other bacteria, Brucella strains require several biologically essential metals for their survival in vitro and in vivo. Acquiring sufficient levels of some of these metals, particularly iron, manganese and zinc, is especially challenging in the mammalian host, where sequestration of these micronutrients is a well-documented component of both the innate and acquired immune responses. This review describes the Brucella metal transporters that have been shown to play critical roles in the virulence of these bacteria in experimental and natural hosts.
Collapse
|
25
|
Eskra L, Covert J, Glasner J, Splitter G. Differential expression of iron acquisition genes by Brucella melitensis and Brucella canis during macrophage infection. PLoS One 2012; 7:e31747. [PMID: 22403618 PMCID: PMC3293887 DOI: 10.1371/journal.pone.0031747] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 01/12/2012] [Indexed: 12/27/2022] Open
Abstract
Brucella spp. cause chronic zoonotic disease often affecting individuals and animals in impoverished economic or public health conditions; however, these bacteria do not have obvious virulence factors. Restriction of iron availability to pathogens is an effective strategy of host defense. For brucellae, virulence depends on the ability to survive and replicate within the host cell where iron is an essential nutrient for the growth and survival of both mammalian and bacterial cells. Iron is a particularly scarce nutrient for bacteria with an intracellular lifestyle. Brucella melitensis and Brucella canis share ∼99% of their genomes but differ in intracellular lifestyles. To identify differences, gene transcription of these two pathogens was examined during infection of murine macrophages and compared to broth grown bacteria. Transcriptome analysis of B. melitensis and B. canis revealed differences of genes involved in iron transport. Gene transcription of the TonB, enterobactin, and ferric anguibactin transport systems was increased in B. canis but not B. melitensis during infection of macrophages. The data suggest differences in iron requirements that may contribute to differences observed in the lifestyles of these closely related pathogens. The initial importance of iron for B. canis but not for B. melitensis helps elucidate differing intracellular survival strategies for two closely related bacteria and provides insight for controlling these pathogens.
Collapse
Affiliation(s)
- Linda Eskra
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jill Covert
- Department of Surgical and Radiological Sciences, University of California Davis, Davis, California, United States of America
| | - Jeremy Glasner
- Biotechnology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Gary Splitter
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
| |
Collapse
|
26
|
Mur regulates the gene encoding the manganese transporter MntH in Brucella abortus 2308. J Bacteriol 2011; 194:561-6. [PMID: 22101848 DOI: 10.1128/jb.05296-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MntH is the only high-affinity manganese transporter identified in Brucella. A previous study showed that MntH is required for the wild-type virulence of Brucella abortus 2308 in mice (Anderson ES, et al., Infect. Immun. 77:3466-3474, 2009) and indicated that the mntH gene is regulated in a manganese-responsive manner in this strain by a Mur homolog. In the study presented here, the transcriptional start site for mntH in B. abortus 2308 was determined by primer extension analysis. Specific interactions between Mur and the mntH promoter region were demonstrated in an electrophoretic mobility shift assay (EMSA), and a Mur binding site was identified in the -55 to -24 region of the mntH promoter by DNase I footprint analysis. The specificity of the interaction of Mur with the putative Mur box was further evaluated by EMSA employing oligonucleotides in which the consensus nucleotides in this region were substituted. These studies not only confirm a direct role for Mur in the Mn-responsive regulation of mntH expression in Brucella abortus 2308 but also identify the cis-acting elements upstream of mntH that are responsible for this regulation.
Collapse
|
27
|
Jain N, Rodriguez AC, Kimsawatde G, Seleem MN, Boyle SM, Sriranganathan N. Effect of entF deletion on iron acquisition and erythritol metabolism by Brucella abortus 2308. FEMS Microbiol Lett 2011; 316:1-6. [PMID: 21204922 DOI: 10.1111/j.1574-6968.2010.02186.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Brucella abortus has been shown to produce two siderophores: 2,3-dihydroxybenzoic acid (2,3-DHBA) and brucebactin. Previous studies on Brucella have shown that 2,3-DHBA is associated with erythritol utilization and virulence in pregnant ruminants. The biosynthetic pathway and role of brucebactin are not known and the only gene shown to be involved so far is entF. Using cre-lox methodology, an entF mutant was created in wild-type B. abortus 2308. Compared with the wild-type strain, the ΔentF strain showed significant growth inhibition in iron minimal media that became exacerbated in the presence of an iron chelator. For the first time, we have demonstrated the death of the ΔentF strain under iron-limiting conditions in the presence of erythritol. Addition of FeCl(3) restored the growth of the ΔentF strain, suggesting a significant role in iron acquisition. Further, complementation of the ΔentF strain using a plasmid containing an entF gene suggested the absence of any polar effects. In contrast, there was no significant difference in survival and growth between the ΔentF and wild-type strains grown in the murine macrophage cell line J774A.1, suggesting that an alternate iron acquisition pathway is present in Brucella when grown intracellulary.
Collapse
Affiliation(s)
- Neeta Jain
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | | | | | | | | | | |
Collapse
|
28
|
Survival of the fittest: how Brucella strains adapt to their intracellular niche in the host. Med Microbiol Immunol 2009; 198:221-38. [PMID: 19830453 DOI: 10.1007/s00430-009-0123-8] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Indexed: 02/06/2023]
Abstract
Brucella strains produce abortion and infertility in their natural hosts and a zoonotic disease in humans known as undulant fever. These bacteria do not produce classical virulence factors, and their capacity to successfully survive and replicate within a variety of host cells underlies their pathogenicity. Extensive replication of the brucellae in placental trophoblasts is associated with reproductive tract pathology in natural hosts, and prolonged persistence in macrophages leads to the chronic infections that are a hallmark of brucellosis in both natural hosts and humans. This review describes how Brucella strains have efficiently adapted to their intracellular lifestyle in the host.
Collapse
|
29
|
Anderson ES, Paulley JT, Gaines JM, Valderas MW, Martin DW, Menscher E, Brown TD, Burns CS, Roop RM. The manganese transporter MntH is a critical virulence determinant for Brucella abortus 2308 in experimentally infected mice. Infect Immun 2009; 77:3466-74. [PMID: 19487482 PMCID: PMC2715675 DOI: 10.1128/iai.00444-09] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 05/03/2009] [Accepted: 05/20/2009] [Indexed: 11/20/2022] Open
Abstract
The gene designated BAB1_1460 in the Brucella abortus 2308 genome sequence is predicted to encode the manganese transporter MntH. Phenotypic analysis of an isogenic mntH mutant indicates that MntH is the sole high-affinity manganese transporter in this bacterium but that MntH does not play a detectable role in the transport of Fe(2+), Zn(2+), Co(2+), or Ni(2+). Consistent with the apparent selectivity of the corresponding gene product, the expression of the mntH gene in B. abortus 2308 is repressed by Mn(2+), but not Fe(2+), and this Mn-responsive expression is mediated by a Mur-like repressor. The B. abortus mntH mutant MWV15 exhibits increased susceptibility to oxidative killing in vitro compared to strain 2308, and a comparative analysis of the superoxide dismutase activities present in these two strains indicates that the parental strain requires MntH in order to make wild-type levels of its manganese superoxide dismutase SodA. The B. abortus mntH mutant also exhibits extreme attenuation in both cultured murine macrophages and experimentally infected C57BL/6 mice. These experimental findings indicate that Mn(2+) transport mediated by MntH plays an important role in the physiology of B. abortus 2308, particularly during its intracellular survival and replication in the host.
Collapse
Affiliation(s)
- Eric S Anderson
- Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, NC 27834, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Purification of Legiobactin and importance of this siderophore in lung infection by Legionella pneumophila. Infect Immun 2009; 77:2887-95. [PMID: 19398549 DOI: 10.1128/iai.00087-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When cultured in a low-iron medium, Legionella pneumophila secretes a siderophore (legiobactin) that is both reactive in the chrome azurol S (CAS) assay and capable of stimulating the growth of iron-starved legionellae. Using anion-exchange high-pressure liquid chromatography (HPLC), we purified legiobactin from culture supernatants of a virulent strain of L. pneumophila. In the process, we detected the ferrated form of legiobactin as well as other CAS-reactive substances. Purified legiobactin had a yellow-gold color and absorbed primarily from 220 nm and below. In accordance, nuclear magnetic resonance spectroscopy revealed that legiobactin lacks aromatic carbons, and among the 13 aliphatics present, there were 3 carbonyls. When examined by HPLC, supernatants from L. pneumophila mutants inactivated for lbtA and lbtB completely lacked legiobactin, indicating that the LbtA and LbtB proteins are absolutely required for siderophore activity. Independently derived lbtA mutants, but not a complemented derivative, displayed a reduced ability to infect the lungs of A/J mice after intratracheal inoculation, indicating that legiobactin is required for optimal intrapulmonary survival by L. pneumophila. This defect, however, was not evident when the lbtA mutant and its parental strain were coinoculated into the lung, indicating that legiobactin secreted by the wild type can promote growth of the mutant in trans. Legiobactin mutants grew normally in murine lung macrophages and alveolar epithelial cells, suggesting that legiobactin promotes something other than intracellular infection of resident lung cells. Overall, these data represent the first documentation of a role for siderophore expression in the virulence of L. pneumophila.
Collapse
|
31
|
Martín-Martín AI, Caro-Hernández P, Sancho P, Tejedor C, Cloeckaert A, Fernández-Lago L, Vizcaíno N. Analysis of the occurrence and distribution of the Omp25/Omp31 family of surface proteins in the six classical Brucella species. Vet Microbiol 2008; 137:74-82. [PMID: 19135812 DOI: 10.1016/j.vetmic.2008.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 12/01/2008] [Accepted: 12/02/2008] [Indexed: 11/28/2022]
Abstract
Members of the Omp25/Omp31 family of surface proteins were previously shown to participate in the virulence of some Brucella species and a different distribution of the seven proteins of this family among species could be related to the difference in pathogenicity and host preference they exhibit. Accordingly, in this work we have analyzed the expression of the genes coding for the Omp25/Omp31 family in the six classical Brucella species and a set of B. ovis mutant strains with each omp gene inactivated. Immunoblot of whole-cell lysates with antibodies raised against the purified recombinant outer membrane proteins (OMPs) did not show the simultaneous presence of the seven OMPs in any of the Brucella strains studied, but different Omp25/Omp31 profiles were detected, in our experimental conditions, between the Brucella strains representative of the six classical species. Transcripts for omp31, omp25 and omp25c were, in general, the most abundant of the family and some hits were found in B. ovis for a posttranscriptional regulation mechanism and for a compensatory mechanism increasing the synthesis of a protein to compensate for the absence of another one. Finally, the potential interest of Omp25c and Omp31b as subcellular vaccines, considering their occurrence in the Brucella strains studied and their antigenic relatedness with other proteins of the family, is discussed.
Collapse
Affiliation(s)
- Ana I Martín-Martín
- Departamento de Microbiología y Genética, Edificio Departamental, Universidad de Salamanca, Plaza Doctores de la Reina s/n, 37007 Salamanca, Spain
| | | | | | | | | | | | | |
Collapse
|
32
|
Genome sequence of Brucella abortus vaccine strain S19 compared to virulent strains yields candidate virulence genes. PLoS One 2008; 3:e2193. [PMID: 18478107 PMCID: PMC2364660 DOI: 10.1371/journal.pone.0002193] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 03/13/2008] [Indexed: 01/07/2023] Open
Abstract
The Brucella abortus strain S19, a spontaneously attenuated strain, has been used as a vaccine strain in vaccination of cattle against brucellosis for six decades. Despite many studies, the physiological and molecular mechanisms causing the attenuation are not known. We have applied pyrosequencing technology together with conventional sequencing to rapidly and comprehensively determine the complete genome sequence of the attenuated Brucella abortus vaccine strain S19. The main goal of this study is to identify candidate virulence genes by systematic comparative analysis of the attenuated strain with the published genome sequences of two virulent and closely related strains of B. abortus, 9–941 and 2308. The two S19 chromosomes are 2,122,487 and 1,161,449 bp in length. A total of 3062 genes were identified and annotated. Pairwise and reciprocal genome comparisons resulted in a total of 263 genes that were non-identical between the S19 genome and any of the two virulent strains. Amongst these, 45 genes were consistently different between the attenuated strain and the two virulent strains but were identical amongst the virulent strains, which included only two of the 236 genes that have been implicated as virulence factors in literature. The functional analyses of the differences have revealed a total of 24 genes that may be associated with the loss of virulence in S19. Of particular relevance are four genes with more than 60bp consistent difference in S19 compared to both the virulent strains, which, in the virulent strains, encode an outer membrane protein and three proteins involved in erythritol uptake or metabolism.
Collapse
|
33
|
Brucella: A pathogen without classic virulence genes. Vet Microbiol 2008; 129:1-14. [DOI: 10.1016/j.vetmic.2007.11.023] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Revised: 11/19/2007] [Accepted: 11/22/2007] [Indexed: 01/18/2023]
|
34
|
The AraC-like transcriptional regulator DhbR is required for maximum expression of the 2,3-dihydroxybenzoic acid biosynthesis genes in Brucella abortus 2308 in response to iron deprivation. J Bacteriol 2007; 190:1838-42. [PMID: 18156262 DOI: 10.1128/jb.01551-07] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phenotypic evaluation of isogenic mutants derived from Brucella abortus 2308 indicates that the AlcR homolog DhbR (2,3-dihydroxybenzoic acid [2,3-DHBA] biosynthesis regulator) modulates the expression of the genes involved in 2,3-DHBA production, employing 2,3-DHBA or brucebactin as a coinducer.
Collapse
|
35
|
Paulley JT, Anderson ES, Roop RM. Brucella abortus requires the heme transporter BhuA for maintenance of chronic infection in BALB/c mice. Infect Immun 2007; 75:5248-54. [PMID: 17709407 PMCID: PMC2168305 DOI: 10.1128/iai.00460-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The gene annotated BAB2_1150 in the Brucella abortus 2308 genome sequence is predicted to encode a homolog of the well-characterized heme transporter ShuA of Shigella dysenteriae and accordingly has been given the designation bhuA (Brucella heme utilization). Phenotypic analysis of an isogenic bhuA mutant derived from B. abortus 2308 verified that there is a link between BhuA and the ability of the parent strain to use heme as an iron source in in vitro assays. Maximum expression of bhuA in B. abortus 2308 is observed during stationary phase when this strain in cultivated in low-iron minimal medium, and a comparison of the growth characteristics of the B. abortus bhuA mutant and 2308 in this medium suggested that heme serves as an important iron source for the parent strain during stationary phase. The B. abortus bhuA mutant HR1703 exhibits significant attenuation in cultured murine macrophages compared to strain 2308, and unlike its parent strain, the B. abortus bhuA mutant is unable to maintain a chronic spleen infection in experimentally infected BALB/c mice. These experimental findings suggest that heme and/or heme-containing proteins represent important iron sources for B. abortus 2308 during its residence in the mammalian host and that BhuA is required for efficient utilization of these iron sources.
Collapse
Affiliation(s)
- James T Paulley
- Department of Microbiology and Immunology, East Carolina University School of Medicine, 600 Moye Boulevard, Greenville, NC 27834, USA
| | | | | |
Collapse
|
36
|
Donadio S, Monciardini P, Sosio M. Polyketide synthases and nonribosomal peptide synthetases: the emerging view from bacterial genomics. Nat Prod Rep 2007; 24:1073-109. [PMID: 17898898 DOI: 10.1039/b514050c] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A total of 223 complete bacterial genomes are analyzed, with 281 citations, for the presence of genes encoding modular polyketide synthases (PKS) and nonribosomal peptide synthetases (NRPS). We report on the distribution of these systems in different bacterial taxa and, whenever known, the metabolites they synthesize. We also highlight, in the different bacterial lineages, the PKS and NRPS genes and, whenever known, the corresponding products.
Collapse
|
37
|
Martínez M, Ugalde RA, Almirón M. Irr regulates brucebactin and 2,3-dihydroxybenzoic acid biosynthesis, and is implicated in the oxidative stress resistance and intracellular survival of Brucella abortus. Microbiology (Reading) 2006; 152:2591-2598. [PMID: 16946254 DOI: 10.1099/mic.0.28782-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Brucella abortusfaces iron deprivation in both nature and the host. To overcome this limitation,Brucellasecretes the siderophores 2,3-dihydroxybenzoic acid and brucebactin. A Fur-like protein named Irr has previously been characterized inB. abortus; this protein is present in theα-2 group ofProteobacteriaonly, where it negatively regulates haem biosynthesis when iron is scarce. Additional evidence that Irr also regulates the synthesis of both siderophores is presented here. TranscriptionallacZfusion and chemical determinations revealed that Irr induced the transcription of the operon involved in the synthesis of the catecholic siderophores, which were consequently secreted under conditions of iron limitation. Irr was able to bind the upstream region of the operon, as shown by electrophoretic mobility shift assay. AB. abortus irrmutant showed higher intracellular haem content, catalase activity and resistance to hydrogen peroxide than the wild-type strain. The mutation also improved the replication and survival of iron-depleted bacteria within cultured mammalian cells. Although the pathogenesis ofBrucellacorrelates with its ability to replicate intracellularly, pathogenicity was not attenuated when assayed in a murine model.
Collapse
Affiliation(s)
- Marcela Martínez
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), San Martín 1650, Argentina
| | - Rodolfo A Ugalde
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), San Martín 1650, Argentina
| | - Marta Almirón
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), San Martín 1650, Argentina
| |
Collapse
|
38
|
Martínez M, Ugalde RA, Almirón M. Dimeric Brucella abortus Irr protein controls its own expression and binds haem. Microbiology (Reading) 2005; 151:3427-3433. [PMID: 16207924 DOI: 10.1099/mic.0.28213-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Brucella abortus needs to synthesize haem in order to replicate intracellularly and to produce virulence in mice. Thus, to gain insight into the pathogenesis of the bacterium, regulatory proteins of the haem biosynthetic pathway were sought. An iron response regulator (Irr) from Bradyrhizobium japonicum, which is a close relative of Brucella, was previously described as being involved in the coordination of haem biosynthesis and iron availability. The Bru. abortus genome was searched for an irr orthologue gene, and the Bru. abortus irr gene was cloned, sequenced and disrupted. A null mutant was constructed that accumulated protoporphyrin IX under conditions of iron deprivation. This phenotype was overcome by a complementing plasmid carrying the wild-type irr. Purified recombinant Bru. abortus Irr behaved as a stable dimer and bound haem. Interestingly, in vivo, Irr was only detected in cells obtained from iron-limited cultures and the protein downregulated its own transcription. Through lacZ fusion, it was demonstrated that iron did not regulate irr transcription. The data reported show that Bru. abortus Irr is a homodimeric protein that is accumulated in iron-limited cells, controls its own transcription and downregulates the biosynthesis of haem precursors.
Collapse
Affiliation(s)
- Marcela Martínez
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), Ed 24, Av. General Paz 5445, San Martín 1650, Buenos Aires, Argentina
| | - Rodolfo A Ugalde
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), Ed 24, Av. General Paz 5445, San Martín 1650, Buenos Aires, Argentina
| | - Marta Almirón
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB, INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de General San Martín (CONICET-UNSAM), Ed 24, Av. General Paz 5445, San Martín 1650, Buenos Aires, Argentina
| |
Collapse
|
39
|
Danese I, Haine V, Delrue RM, Tibor A, Lestrate P, Stevaux O, Mertens P, Paquet JY, Godfroid J, De Bolle X, Letesson JJ. The Ton system, an ABC transporter, and a universally conserved GTPase are involved in iron utilization by Brucella melitensis 16M. Infect Immun 2004; 72:5783-90. [PMID: 15385478 PMCID: PMC517599 DOI: 10.1128/iai.72.10.5783-5790.2004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Brucella spp. are gram-negative intracellular facultative pathogens that are known to produce 2,3-dihydroxybenzoic acid (DHBA), a catechol siderophore that is essential for full virulence in the natural host. The mechanism of DHBA entry into Brucella and other gram-negative bacteria is poorly understood. Using mini-Tn5Kmcat mutagenesis, we created a transposon library of Brucella melitensis 16M and isolated 32 mutants with a defect in iron acquisition or assimilation. Three of these transposon mutants are deficient in utilization of DHBA. Analysis of these three mutants indicated that the ExbB, DstC, and DugA proteins are required for optimal assimilation of DHBA and/or citrate. ExbB is part of the Ton complex, and DstC is a permease homologue of an iron(III) ABC transporter; in gram-negative bacteria these two complexes are involved in the uptake of iron through the outer and inner membranes, respectively. DugA is a new partner in iron utilization that exhibits homology with the bacterial conserved GTPase YchF. Based on this homology, DugA could have a putative regulatory function in iron assimilation in Brucella. None of the three mutants was attenuated in cellular models or in the mouse model of infection, which is consistent with the previous suggestion that DHBA utilization is not required in these models.
Collapse
Affiliation(s)
- Isabelle Danese
- Unité de Recherche en Biologie Moléculaire, University of Namur, Belgium.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Mihara K, Tanabe T, Yamakawa Y, Funahashi T, Nakao H, Narimatsu S, Yamamoto S. Identification and transcriptional organization of a gene cluster involved in biosynthesis and transport of acinetobactin, a siderophore produced by Acinetobacter baumannii ATCC 19606T. MICROBIOLOGY-SGM 2004; 150:2587-2597. [PMID: 15289555 DOI: 10.1099/mic.0.27141-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In order to assimilate iron, Acinetobacter baumannii ATCC 19606(T) produces a siderophore named acinetobactin (Ab) that is composed of equimolar quantities of 2,3-dihydroxybenzoic acid (DHBA), L-threonine and N-hydroxyhistamine. Application of the Fur titration assay system to A. baumannii genomic libraries, followed by further cloning of the regions surrounding the candidate genes, led to the identification of the Ab cluster, which harbours the genetic determinants necessary for the biosynthesis and transport of the siderophore. However, an entA homologue essential for DHBA biosynthesis was not found in this cluster. Functions of potential biosynthetic genes inferred by homology studies suggested that the precursors, DHBA, l-threonine and N-hydroxyhistamine, are linked in steps resembling those of bacterial non-ribosomal peptide synthesis to form Ab. Genes responsible for the two-step biosynthesis of N-hydroxyhistamine from histidine were also identified in this cluster. Their genetic organization suggests that five genes involved in the transport system of ferric Ab into the cell cytosol form an operon. Construction of disruptants of some selected genes followed by phenotypic analysis supported their predicted biological functions. Interestingly, three additional genes probably involved in the intracellular release of iron from ferric Ab and the secretion of nascent Ab are contained in this cluster. Primer extension and RT-PCR analyses suggested that the Ab cluster, which includes 18 genes, is organized in seven transcriptional units originating from respective Fur-regulated promoter-operator regions.
Collapse
Affiliation(s)
- Kazutoshi Mihara
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Tomotaka Tanabe
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Yoshiko Yamakawa
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Tatsuya Funahashi
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Hiroshi Nakao
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Shizuo Narimatsu
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| | - Shigeo Yamamoto
- Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
| |
Collapse
|
41
|
Abstract
Members of the bacterial genus Brucella are facultative intracellular pathogens that reside predominantly within membrane-bound compartments within two host cell types, macrophages and placental trophoblasts. Within macrophages, the brucellae route themselves to an intracellular compartment that is favourable for survival and replication, and they also appear to be well-adapted from a physiological standpoint to withstand the environmental conditions encountered during prolonged residence in this intracellular niche. Much less is known about the interactions of the Brucella with placental trophoblasts, but experimental evidence suggests that these bacteria use an iron acquisition system to support extensive intracellular replication within these host cells that is not required for survival and replication in host macrophages. Thus, it appears that the brucellae rely upon the products of distinct subsets of genes to adapt successfully to the environmental conditions encountered within the two cell types within which they reside in their mammalian hosts.
Collapse
Affiliation(s)
- R Martin Roop
- Department of Microbiology and Immunology, East Carolina University School of Medicine, 600 Moye Boulevard, Greenville, NC 27858-4354, USA.
| | | | | | | |
Collapse
|
42
|
Pierwola A, Krupinski T, Zalupski P, Chiarelli M, Castignetti D. Degradation pathway and generation of monohydroxamic acids from the trihydroxamate siderophore deferrioxamine B. Appl Environ Microbiol 2004; 70:831-6. [PMID: 14766561 PMCID: PMC348822 DOI: 10.1128/aem.70.2.831-836.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Siderophores are avid ferric ion-chelating molecules that sequester the metal for microbes. Microbes elicit siderophores in numerous and different environments, but the means by which these molecules reenter the carbon and nitrogen cycles is poorly understood. The metabolism of the trihydroxamic acid siderophore deferrioxamine B by a Mesorhizobium loti isolated from soil was investigated. Specifically, the pathway by which the compound is cleaved into its constituent monohydroxamates was examined. High-performance liquid chromatography and mass-spectroscopy analyses demonstrated that M. loti enzyme preparations degraded deferrioxamine B, yielding a mass-to-charge (m/z) 361 dihydroxamic acid intermediate and an m/z 219 monohydroxamate. The dihydroxamic acid was further degraded to yield a second molecule of the m/z 219 monohydroxamate as well as an m/z 161 monohydroxamate. These studies indicate that the dissimilation of deferrioxamine B by M. loti proceeds by a specific, achiral degradation and likely represents the reversal by which hydroxamate siderophores are thought to be synthesized.
Collapse
Affiliation(s)
- Agnes Pierwola
- Department of Biology, Loyola University of Chicago, Chicago, Illinois 60626, USA
| | | | | | | | | |
Collapse
|
43
|
Cendrowski S, MacArthur W, Hanna P. Bacillus anthracis requires siderophore biosynthesis for growth in macrophages and mouse virulence. Mol Microbiol 2004; 51:407-17. [PMID: 14756782 DOI: 10.1046/j.1365-2958.2003.03861.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Systemic anthrax infections can be characterized as proceeding in stages, beginning with an early intracellular establishment stage within phagocytes that is followed by extracelluar stages involving massive bacteraemia, sepsis and death. Because most bacteria require iron, and the host limits iron availability through homeostatic mechanisms, we hypothesized that B. anthracis requires a high-affinity mechanism of iron acquisition during its growth stages. Two putative types of siderophore synthesis operons, named Bacillus anthracis catechol, bac (anthrabactin), and anthrax siderophore biosynthesis, asb (anthrachelin), were identified. Directed gene deletions in both anthrabactin and anthrachelin pathways were generated in a B. anthracis (Sterne) 34F2 background resulting in mutations in asbA and bacCEBF. A decrease in siderophore production was observed during iron-depleted growth in both the DeltaasbA and DeltabacCEBF strains, but only the DeltaasbA strain was attenuated for growth under these conditions. In addition, the DeltaasbA strain was severely attenuated both for growth in macrophages (MPhi) and for virulence in mice. In contrast, the DeltabacCEBF strain did not differ phenotypically from the parental strain. These findings support a requirement for anthrachelin but not anthrabactin in iron assimilation during the intracellular stage of anthrax.
Collapse
Affiliation(s)
- Stephen Cendrowski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | | |
Collapse
|
44
|
Delrue RM, Lestrate P, Tibor A, Letesson JJ, De Bolle X. Brucellapathogenesis, genes identified from random large-scale screens. FEMS Microbiol Lett 2004; 231:1-12. [PMID: 14979322 DOI: 10.1016/s0378-1097(03)00963-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pathogenicity islands, specialized secretion systems, virulence plasmids, fimbriae, pili, adhesins, and toxins are all classical bacterial virulence factors. However, many of these factors, though widespread among bacterial pathogens, are not necessarily found among bacteria that colonize eukaryotic cells in a pathogenic/symbiotic relationship. Bacteria that form these relationships have developed other strategies to infect and grow in their hosts. This is particularly true for Brucella and other members of the class Proteobacteria. Thus far the identification of virulence factors for Brucella has been largely dependent on large-scale screens and testing in model systems. The genomes of the facultative intracellular pathogens Brucella melitensis and Brucella suis were sequenced recently. This has identified several more potential virulence factors for Brucella that were not found in large screens. Here, we present an overall view of Brucella virulence by compiling virulence data from the study of 184 attenuated mutants.
Collapse
Affiliation(s)
- Rose-May Delrue
- Unité de Recherche en Biologie Moléculaire (URBM), Laboratoire d'Immunologie et de Microbiologie, Université de Namur, Namur, Belgium
| | | | | | | | | |
Collapse
|