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Pierlé SA, Lang M, López-Igual R, Krin E, Fourmy D, Kennedy SP, Val ME, Baharoglu Z, Mazel D. Identification of the active mechanism of aminoglycoside entry in V. cholerae through characterization of sRNA ctrR, regulating carbohydrate utilization and transport. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549712. [PMID: 37502966 PMCID: PMC10370196 DOI: 10.1101/2023.07.19.549712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The possible active entry of aminoglycosides in bacterial cells has been debated since the development of this antibiotic family. Here we report the identification of their active transport mechanism in Vibrio species. We combined genome-wide transcriptional analysis and fitness screens to identify alterations driven by treatment of V. cholerae with sub-minimum inhibitory concentrations (sub-MIC) of the aminoglycoside tobramycin. RNA-seq data showed downregulation of the small non-coding RNA ncRNA586 during such treatment, while Tn-seq revealed that inactivation of this sRNA was associated with improved fitness in the presence of tobramycin. This sRNA is located near sugar transport genes and previous work on a homologous region in Vibrio tasmaniensis suggested that this sRNA stabilizes gene transcripts for carbohydrate transport and utilization, as well as phage receptors. The role for ncRNA586, hereafter named ctrR, in the transport of both carbohydrates and aminoglycosides, was further investigated. Flow cytometry on cells treated with a fluorescent aminoglycoside confirmed the role of ctrR and of carbohydrate transporters in differential aminoglycoside entry. Despite sequence diversity, ctrR showed functional conservation across the Vibrionales. This system in directly modulated by carbon sources, suggesting regulation by carbon catabolite repression, a widely conserved mechanism in Gram-negative bacteria, priming future research on aminoglycoside uptake by sugar transporters in other bacterial species.
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Affiliation(s)
- Sebastian A. Pierlé
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Manon Lang
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Rocío López-Igual
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Evelyne Krin
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Dominique Fourmy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Sean P. Kennedy
- Institut Pasteur, Université Paris Cité, USR 3756 CNRS, Department of Computational Biology, 75015 Paris, France
| | - Marie-Eve Val
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Zeynep Baharoglu
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, F-75015 Paris, France
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Liebenberg J, Steyn HC, Josemans AI, Faber E, Zweygarth E. In vitro propagation and genome sequencing of three 'atypical' Ehrlichia ruminantium isolates. ACTA ACUST UNITED AC 2020; 87:e1-e14. [PMID: 32633992 PMCID: PMC7343930 DOI: 10.4102/ojvr.v87i1.1769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 09/06/2019] [Accepted: 10/01/2019] [Indexed: 12/01/2022]
Abstract
Three isolates of Ehrlichia ruminantium (Kümm 2, Omatjenne and Riverside), the causative agent of heartwater in domestic ruminants, were isolated in Ixodes scapularis (IDE8) tick cell cultures using the leukocyte fraction of infected sheep blood. All stocks were successfully propagated in IDE8 cells, whereas initiation attempts using endothelial cell cultures were unsuccessful. Therefore, the new technique should be included in any attempt to isolate field strains of E. ruminantium to enhance the probability of getting E. ruminantium isolates which might not be initiated in endothelial cells. Draft genome sequences of all three isolates were generated and compared with published genomes. The data confirmed previous phylogenetic studies that these three isolates are genetically very close to each other, but distinct from previously characterised E. ruminantium isolates. Genome comparisons indicated that the gene content and genomic synteny were highly conserved, with the exception of the membrane protein families. These findings expand our understanding of the genetic diversity of E. ruminantium and confirm the distinct phenotypic and genetic characteristics shared by these three isolates.
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Affiliation(s)
- Junita Liebenberg
- Vaccines and Diagnostics Development Programme, ARC-Onderstepoort Veterinary Research, Pretoria.
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Soler-Bistué A, Aguilar-Pierlé S, Garcia-Garcerá M, Val ME, Sismeiro O, Varet H, Sieira R, Krin E, Skovgaard O, Comerci DJ, Rocha EPC, Mazel D. Macromolecular crowding links ribosomal protein gene dosage to growth rate in Vibrio cholerae. BMC Biol 2020; 18:43. [PMID: 32349767 PMCID: PMC7191768 DOI: 10.1186/s12915-020-00777-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/31/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In fast-growing bacteria, the genomic location of ribosomal protein (RP) genes is biased towards the replication origin (oriC). This trait allows optimizing their expression during exponential phase since oriC neighboring regions are in higher dose due to multifork replication. Relocation of s10-spc-α locus (S10), which codes for most of the RP, to ectopic genomic positions shows that its relative distance to the oriC correlates to a reduction on its dosage, its expression, and bacterial growth rate. However, a mechanism linking S10 dosage to cell physiology has still not been determined. RESULTS We hypothesized that S10 dosage perturbations impact protein synthesis capacity. Strikingly, we observed that in Vibrio cholerae, protein production capacity was independent of S10 position. Deep sequencing revealed that S10 relocation altered chromosomal replication dynamics and genome-wide transcription. Such changes increased as a function of oriC-S10 distance. Since RP constitutes a large proportion of cell mass, lower S10 dosage could lead to changes in macromolecular crowding, impacting cell physiology. Accordingly, cytoplasm fluidity was higher in mutants where S10 is most distant from oriC. In hyperosmotic conditions, when crowding differences are minimized, the growth rate and replication dynamics were highly alleviated in these strains. CONCLUSIONS The genomic location of RP genes ensures its optimal dosage. However, besides of its essential function in translation, their genomic position sustains an optimal macromolecular crowding essential for maximizing growth. Hence, this could be another mechanism coordinating DNA replication to bacterial growth.
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Affiliation(s)
- Alfonso Soler-Bistué
- Institut Pasteur, Unité Plasticité du Génome Bactérien, UMR3525, CNRS, Paris, France
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," CONICET - Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | | | - Marc Garcia-Garcerá
- Microbial Evolutionary Genomics, Département Génomes et Génétique, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3525, Paris, France
- Department of Fundamental Microbiology, University of Lausanne, Quartier SORGE, 1003, Lausanne, Switzerland
| | - Marie-Eve Val
- Institut Pasteur, Unité Plasticité du Génome Bactérien, UMR3525, CNRS, Paris, France
| | - Odile Sismeiro
- Institut Pasteur, Plate-forme Transcriptome et Épigenome, Biomics, Centre d'Innovation et Recherche Technologique (Citech), Paris, France
| | - Hugo Varet
- Institut Pasteur, Plate-forme Transcriptome et Épigenome, Biomics, Centre d'Innovation et Recherche Technologique (Citech), Paris, France
| | - Rodrigo Sieira
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Evelyne Krin
- Institut Pasteur, Unité Plasticité du Génome Bactérien, UMR3525, CNRS, Paris, France
| | - Ole Skovgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Diego J Comerci
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," CONICET - Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Eduardo P C Rocha
- Microbial Evolutionary Genomics, Département Génomes et Génétique, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3525, Paris, France
| | - Didier Mazel
- Institut Pasteur, Unité Plasticité du Génome Bactérien, UMR3525, CNRS, Paris, France.
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Dynamics of repeat-associated plasticity in the aaap gene family in Anaplasma marginale. Gene X 2019; 721S:100010. [PMID: 32099970 PMCID: PMC7041399 DOI: 10.1016/j.gene.2019.100010] [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: 01/05/2019] [Revised: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 11/23/2022] Open
Abstract
Anaplasmosis, the most prevalent tick-transmitted disease of cattle, is caused by the rickettsial intracellular parasite Anaplasma marginale. The pathogen replicates within a parasitophorous vacuole formed from the invagination of the erythrocyte membrane. Several strains of A. marginale form "tails" or "appendages" which are attached to, and extend out from, the cytoplasmic side of the parasitophorous vacuole. Genomic analysis of the parasite antigen distributed along the appendage led to the discovery of the aaap (Anaplasma appendage associated protein) gene family located within a highly plastic region in the genome. The aaap gene family consists of aaap and several alps (for aaap-like proteins), depending on the strain. These genes/proteins are characterized by repeat sequences. To investigate locus plasticity, different versions of the locus were cloned from the same strain as well as from different strains, sequenced and aligned to identify changes. Our findings show that repeat sequences both within and between genes facilitated rearrangement events within the locus. Structural variation of the locus in the St. Maries strain was further investigated during infection of different cellular environments, i.e., bovine erythrocytes and tick cells, with a reduction in subpopulations of the aaap locus within the tick as compared to erythrocytes. Interestingly, subpopulations bearing alternative locus structures began to arise again when the pathogen was transferred from the tick environment into a naïve calf. Additionally, the Aaap protein expression profile between blood and tick samples showed a regulatory shift, indicating a host-specific response. Alignment of the protein sequences from different species of Anaplasma reveals six similar repeating motifs that appear to be unique to a few species of Anaplasma. The role the aaap locus may play in the pathogenesis of the bovine host or in tick infection/transmission remains unknown; however, the changes in aaap locus subpopulations, locus structure, and protein expression indicate that these genes have a role in strain diversification.
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Kondethimmanahalli C, Ganta R. Impact of Three Different Mutations in Ehrlichia chaffeensis in Altering the Global Gene Expression Patterns. Sci Rep 2018; 8:6162. [PMID: 29670161 PMCID: PMC5906474 DOI: 10.1038/s41598-018-24471-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/26/2018] [Indexed: 02/06/2023] Open
Abstract
The rickettsial pathogen Ehrlichia chaffeensis causes a tick-borne disease, human monocytic ehrlichiosis. Mutations within certain genomic locations of the pathogen aid in understanding the pathogenesis and in developing attenuated vaccines. Our previous studies demonstrated that mutations in different genomic sites in E. chaffeensis caused variable impacts on their growth and attenuation in vertebrate and tick hosts. Here, we assessed the effect of three mutations on transcriptional changes using RNA deep-sequencing technology. RNA sequencing aided in detecting 66-80% of the transcripts of wildtype and mutant E. chaffeensis. Mutation in an antiporter gene (ECH_0379) causing attenuated growth in vertebrate hosts resulted in the down regulation of many transcribed genes. Similarly, a mutation downstream to the ECH_0490 coding sequence resulted in minimal impact on the pathogen's in vivo growth, but caused major changes in its transcriptome. This mutation caused enhanced expression of several host stress response genes. Even though the ECH_0660 gene mutation caused the pathogen's rapid clearance in vertebrate hosts and aids in generating a protective response, there was minimal impact on the transcriptome. The transcriptomic data offer novel insights about the impact of mutations on global gene expression and how they may contribute to the pathogen's resistance and/or clearance from the host.
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Affiliation(s)
- Chandramouli Kondethimmanahalli
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, 66506, USA
| | - Roman Ganta
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, 66506, USA.
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Muñoz-Gutiérrez JF, Aguilar Pierlé S, Schneider DA, Baszler TV, Stanton JB. Transcriptomic Determinants of Scrapie Prion Propagation in Cultured Ovine Microglia. PLoS One 2016; 11:e0147727. [PMID: 26807844 PMCID: PMC4726464 DOI: 10.1371/journal.pone.0147727] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/07/2016] [Indexed: 12/22/2022] Open
Abstract
Susceptibility to infection by prions is highly dependent on the amino acid sequence and host expression of the cellular prion protein (PrPC); however, cellular expression of a genetically susceptible PrPC is insufficient. As an example, it has been shown in cultured cells that permissive and resistant sublines derived from the same parental population often have similar expression levels of PrPC. Thus, additional cellular factors must influence susceptibility to prion infection. The aim of this study was to elucidate the factors associated with relative permissiveness and resistance to scrapie prions in cultured cells derived from a naturally affected species. Two closely related ovine microglia clones with different prion susceptibility, but no detectable differences in PrPC expression levels, were inoculated with either scrapie-positive or scrapie-negative sheep brainstem homogenates. Five passages post-inoculation, the transcriptional profiles of mock and infected clones were sequenced using Illumina technology. Comparative transcriptional analyses identified twenty-two differentially transcribed genes, most of which were upregulated in poorly permissive microglia. This included genes encoding for selenoprotein P, endolysosomal proteases, and proteins involved in extracellular matrix remodeling. Furthermore, in highly permissive microglia, transforming growth factor β–induced, retinoic acid receptor response 1, and phosphoserine aminotranspherase 1 gene transcripts were upregulated. Gene Set Enrichment Analysis identified proteolysis, translation, and mitosis as the most affected pathways and supported the upregulation trend of several genes encoding for intracellular proteases and ribosomal proteins in poorly permissive microglia. This study identifies new genes potentially involved in scrapie prion propagation, corroborates results from other studies, and extends those results into another cell culture model.
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Affiliation(s)
- Juan F. Muñoz-Gutiérrez
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail: (JFMG); (JBS)
| | - Sebastián Aguilar Pierlé
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - David A. Schneider
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- United States Department of Agriculture, Agricultural Research Service, Pullman, Washington, United States of America
| | - Timothy V. Baszler
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - James B. Stanton
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (JFMG); (JBS)
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de Barsy M, Bertelli C, Jacquier N, Kebbi-Beghdadi C, Greub G. ESCCAR international congress on Rickettsia and other intracellular bacteria. Microbes Infect 2015; 17:680-8. [PMID: 26297854 DOI: 10.1016/j.micinf.2015.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 07/08/2015] [Indexed: 11/17/2022]
Abstract
The European Society for the study of Chlamydia, Coxiella, Anaplasma and Rickettsia (ESCCAR) held his triennial international meeting in Lausanne. This meeting gathered 165 scientists from 28 countries and all 5 continents, allowing efficient networking and major scientific exchanges. Topics covered include molecular and cellular microbiology, genomics, as well as epidemiology, veterinary and human medicine. Several breakthroughs have been revealed at the meeting, such as (i) the presence of CRISPR (the "prokaryotic immune system") in chlamydiae, (ii) an Anaplasma effector involved in host chromatin remodelling, (iii) the polarity of the type III secretion system of chlamydiae during the entry process revealed by cryo-electron tomography. Moreover, the ESCCAR meeting was a unique opportunity to be exposed to cutting-edge science and to listen to comprehensive talks on current hot topics.
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Affiliation(s)
- Marie de Barsy
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Claire Bertelli
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Nicolas Jacquier
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Carole Kebbi-Beghdadi
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
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Reduced Infectivity in cattle for an outer membrane protein mutant of Anaplasma marginale. Appl Environ Microbiol 2015; 81:2206-14. [PMID: 25595772 DOI: 10.1128/aem.03241-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaplasma marginale is the causative agent of anaplasmosis in cattle. Transposon mutagenesis of this pathogen using the Himar1 system resulted in the isolation of an omp10 operon insertional mutant referred to as the omp10::himar1 mutant. The work presented here evaluated if this mutant had morphological and/or growth rate defects compared to wild-type A. marginale. Results showed that the morphology, developmental cycle, and growth in tick and mammalian cell cultures are similar for the mutant and the wild type. Tick transmission experiments established that tick infection levels with the mutant were similar to those with wild-type A. marginale and that infected ticks successfully infected cattle. However, this mutant exhibited reduced infectivity and growth in cattle. The possibility of transforming A. marginale by transposon mutagenesis coupled with in vitro and in vivo assessment of altered phenotypes can aid in the identification of genes associated with virulence. The isolation of deliberately attenuated organisms that can be evaluated in their natural biological system is an important advance for the rational design of vaccines against this species.
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Del Chierico F, Ancora M, Marcacci M, Cammà C, Putignani L, Conti S. Choice of next-generation sequencing pipelines. Methods Mol Biol 2015; 1231:31-47. [PMID: 25343857 DOI: 10.1007/978-1-4939-1720-4_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The next-generation sequencing (NGS) technologies are revolutionary tools which have made possible achieving remarkable advances in genetics since the beginning of the twenty-first century. Thanks to the possibility to produce large amount of sequence data, these tools are going to completely substitute other high-throughput technologies. Moreover, the large applications of NGS protocols are increasing the genetic decoding of biological systems through studies of genome anatomy and gene mapping, coupled to the transcriptome pictures. The application of NGS pipelines such as (1) de-novo genomic sequencing by mate-paired and whole-genome shotgun strategies; (2) specific gene sequencing on large bacterial communities; and (3) RNA-seq methods including whole transcriptome sequencing and Serial Analysis of Gene Expression (Sage-analysis) are fundamental in the genome-wide fields like metagenomics. Recently, the availability of these advanced protocols has allowed to overcome the usual sequencing technical issues related to the mapping specificity over standard shotgun library sequencing, the detection of large structural genomes variations and bridging sequencing gaps, as well as more precise gene annotation. In this chapter we will discuss how to manage a successful NGS pipeline from the planning of sequencing projects through the choice of the platforms up to the data analysis management.
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Affiliation(s)
- F Del Chierico
- Unit of Parasitology & Unit of Metagenomics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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Hammac GK, Pierlé SA, Cheng X, Scoles GA, Brayton KA. Global transcriptional analysis reveals surface remodeling of Anaplasma marginale in the tick vector. Parasit Vectors 2014; 7:193. [PMID: 24751137 PMCID: PMC4022386 DOI: 10.1186/1756-3305-7-193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/08/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Pathogens dependent upon vectors for transmission to new hosts undergo environment specific changes in gene transcription dependent on whether they are replicating in the vector or the mammalian host. Differential gene transcription, especially of potential vaccine candidates, is of interest in Anaplasma marginale, the tick-borne causative agent of bovine anaplasmosis. METHODS RNA-seq technology allowed a comprehensive analysis of the transcriptional status of A. marginale genes in two conditions: bovine host blood and tick derived cell culture, a model for the tick vector. Quantitative PCR was used to assess transcription of a set of genes in A. marginale infected tick midguts and salivary glands at two time points during the transmission cycle. RESULTS Genes belonging to fourteen pathways or component groups were found to be differentially transcribed in A. marginale in the bovine host versus the tick vector. One of the most significantly altered groups was composed of surface proteins. Of the 56 genes included in the surface protein group, eight were up regulated and 26 were down regulated. The down regulated surface protein encoding genes include several that are well studied due to their immunogenicity and function. Quantitative PCR of a set of genes demonstrated that transcription in tick cell culture most closely approximates transcription in salivary glands of recently infected ticks. CONCLUSIONS The ISE6 tick cell culture line is an acceptable model for early infection in tick salivary glands, and reveals disproportionate down regulation of surface protein genes in the tick. Transcriptional profiling in other cell lines may help us simulate additional microenvironments. Understanding vector-specific alteration of gene transcription, especially of surface protein encoding genes, may aid in the development of vaccines or transmission blocking therapies.
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Affiliation(s)
| | | | | | | | - Kelly A Brayton
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Paul G, Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7040, USA.
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11
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Crosby FL, Wamsley HL, Pate MG, Lundgren AM, Noh SM, Munderloh UG, Barbet AF. Knockout of an outer membrane protein operon of Anaplasma marginale by transposon mutagenesis. BMC Genomics 2014; 15:278. [PMID: 24725301 PMCID: PMC4198910 DOI: 10.1186/1471-2164-15-278] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 03/31/2014] [Indexed: 01/09/2023] Open
Abstract
Background The large amounts of data generated by genomics, transcriptomics and proteomics have increased our understanding of the biology of Anaplasma marginale. However, these data have also led to new assumptions that require testing, ideally through classical genetic mutation. One example is the definition of genes associated with virulence. Here we describe the molecular characterization of a red fluorescent and spectinomycin and streptomycin resistant A. marginale mutant generated by Himar1 transposon mutagenesis. Results High throughput genome sequencing to determine the Himar1-A. marginale genome junctions established that the transposon sequences were integrated within the coding region of the omp10 gene. This gene is arranged within an operon with AM1225 at the 5’ end and with omp9, omp8, omp7 and omp6 arranged in tandem at the 3’ end. RNA analysis to determine the effects of the transposon insertion on the expression of omp10 and downstream genes revealed that the Himar1 insertion not only reduced the expression of omp10 but also that of downstream genes. Transcript expression from omp9, and omp8 dropped by more than 90% in comparison with their counterparts in wild-type A. marginale. Immunoblot analysis showed a reduction in the production of Omp9 protein in these mutants compared to wild-type A. marginale. Conclusions These results demonstrate that transposon mutagenesis in A. marginale is possible and that this technology can be used for the creation of insertional gene knockouts that can be evaluated in natural host-vector systems.
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Affiliation(s)
- Francy L Crosby
- College of Veterinary Medicine, University of Florida, Department of Infectious Diseases and Pathology, 2015 SW 16th avenue, Gainesville, FL 32610, USA.
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Aguilar Pierlé S, Imaz Rosshandler I, Akim Kerudin A, Sambono J, Lew-Tabor A, Rolls P, Rangel-Escareño C, Brayton KA. Genetic Diversity of Tick-Borne Rickettsial Pathogens; Insights Gained from Distant Strains. Pathogens 2014; 3:57-72. [PMID: 25364572 PMCID: PMC4213813 DOI: 10.3390/pathogens3010057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The ability to capture genetic variation with unprecedented resolution improves our understanding of bacterial populations and their ability to cause disease. The goal of the pathogenomics era is to define genetic diversity that results in disease. Despite the economic losses caused by vector-borne bacteria in the Order Rickettsiales, little is known about the genetic variants responsible for observed phenotypes. The tick-transmitted rickettsial pathogen Anaplasma marginale infects cattle in tropical and subtropical regions worldwide, including Australia. Genomic analysis of North American A. marginale strains reveals a closed core genome defined by high levels of Single Nucleotide Polymorphisms (SNPs). Here we report the first genome sequences and comparative analysis for Australian strains that differ in virulence and transmissibility. A list of genetic differences that segregate with phenotype was evaluated for the ability to distinguish the attenuated strain from virulent field strains. Phylogenetic analyses of the Australian strains revealed a marked evolutionary distance from all previously sequenced strains. SNP analysis showed a strikingly reduced genetic diversity between these strains, with the smallest number of SNPs detected between any two A. marginale strains. The low diversity between these phenotypically distinct bacteria presents a unique opportunity to identify the genetic determinants of virulence and transmission.
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Affiliation(s)
- Sebastián Aguilar Pierlé
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7040, USA
- Authors to whom correspondence should be addressed; E-Mails: (S.A.P.); (K.A.B.); Tel.: +509-335-6340 (K.A.B. and S.A.P.); Fax: +509-335-8529 (K.A.B. & S.A.P.)
| | - Ivan Imaz Rosshandler
- National Institute of Genomic Medicine, Computational Genomics Lab, Mexico City 14610, Mexico; E-Mails: (I.I.R.); (C.R.-E.)
| | - Ammielle Akim Kerudin
- The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, St. Lucia, Queensland 4072, Australia; E-Mails: (A.A.K.); (A.L.-T.)
| | - Jacqueline Sambono
- Queensland Department of Agriculture, Fisheries & Forestry, Tick Fever Centre, Wacol, Queensland 4076, Australia; E-Mails: (J.S.); (P.R.)
| | - Ala Lew-Tabor
- The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, St. Lucia, Queensland 4072, Australia; E-Mails: (A.A.K.); (A.L.-T.)
| | - Peter Rolls
- Queensland Department of Agriculture, Fisheries & Forestry, Tick Fever Centre, Wacol, Queensland 4076, Australia; E-Mails: (J.S.); (P.R.)
| | - Claudia Rangel-Escareño
- National Institute of Genomic Medicine, Computational Genomics Lab, Mexico City 14610, Mexico; E-Mails: (I.I.R.); (C.R.-E.)
| | - Kelly A. Brayton
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7040, USA
- Authors to whom correspondence should be addressed; E-Mails: (S.A.P.); (K.A.B.); Tel.: +509-335-6340 (K.A.B. and S.A.P.); Fax: +509-335-8529 (K.A.B. & S.A.P.)
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Abstract
Over the last ten years, genome sequencing capabilities have expanded exponentially. There have been tremendous advances in sequencing technology, DNA sample preparation, genome assembly, and data analysis. This has led to advances in a number of facets of bacterial genomics, including metagenomics, clinical medicine, bacterial archaeology, and bacterial evolution. This review examines the strengths and weaknesses of techniques in bacterial genome sequencing, upcoming technologies, and assembly techniques, as well as highlighting recent studies that highlight new applications for bacterial genomics.
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Affiliation(s)
- Michael J Dark
- Department of Infectious Diseases and Pathology and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
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Pierlé SA, Hammac GK, Palmer GH, Brayton KA. Transcriptional pathways associated with the slow growth phenotype of transformed Anaplasma marginale. BMC Genomics 2013; 14:272. [PMID: 23607288 PMCID: PMC3646689 DOI: 10.1186/1471-2164-14-272] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/26/2013] [Indexed: 11/29/2022] Open
Abstract
Background The ability to genetically manipulate bacteria has been fundamentally important for both basic biological discovery and translational research to develop new vaccines and antibiotics. Experimental alteration of the genetic content of prokaryotic pathogens has revealed both expected functional relationships and unexpected phenotypic consequences. Slow growth phenotypes have been reported for multiple transformed bacterial species, including extracellular and intracellular pathogens. Understanding the genes and pathways responsible for the slow growth phenotype provides the opportunity to develop attenuated vaccines as well as bacteriostatic antibiotics. Transformed Anaplasma marginale, a rickettsial pathogen, exhibits slow growth in vitro and in vivo as compared to the parent wild type strain, providing the opportunity to identify the underlying genes and pathways associated with this phenotype. Results Whole genome transcriptional profiling allowed for identification of specific genes and pathways altered in transformed A. marginale. Genes found immediately upstream and downstream of the insertion site, including a four gene operon encoding key outer membrane proteins, were not differentially transcribed between wild type and transformed A. marginale. This lack of significant difference in transcription of flanking genes and the large size of the insert relative to the genome were consistent with a trans rather than a cis effect. Transcriptional profiling across the complete genome identified the most differentially transcribed genes, including an iron transporter, an RNA cleaving enzyme and several genes involved in translation. In order to confirm the trend seen in translation-related genes, K-means clustering and Gene Set Enrichment Analysis (GSEA) were applied. These algorithms allowed evaluation of the behavior of genes as groups that share transcriptional status or biological function. Clustering and GSEA confirmed the initial observations and found additional pathways altered in transformed A. marginale. Three pathways were significantly altered as compared to the wild type: translation, translation elongation, and purine biosynthesis. Conclusions Identification of perturbed genes and networks through genome wide transcriptional profiling highlights the relevance of pathways such as nucleotide biosynthesis, translation, and translation elongation in the growth phenotype of obligate intracellular bacteria. These genes and pathways provide specific targets for development of slow growing attenuated vaccines and for bacteriostatic antibiotics.
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Affiliation(s)
- Sebastián Aguilar Pierlé
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7040, USA.
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