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Borşan SD, Ionică AM, Galon C, Toma-Naic A, Peştean C, Sándor AD, Moutailler S, Mihalca AD. High Diversity, Prevalence, and Co-infection Rates of Tick-Borne Pathogens in Ticks and Wildlife Hosts in an Urban Area in Romania. Front Microbiol 2021; 12:645002. [PMID: 33767683 PMCID: PMC7985354 DOI: 10.3389/fmicb.2021.645002] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/05/2021] [Indexed: 12/14/2022] Open
Abstract
Despite the increasingly recognized eco-epidemiological importance of ticks as vectors for numerous zoonotic pathogens in urban areas, data regarding the pathogen diversity and co-infection rates in ticks and wildlife hosts in urban and peri-urban Romania are scanty. We aimed to establish the risk of human exposure to co-infected ticks in Cluj-Napoca, a major city in Romania. DNA was isolated from 151 questing ticks: Ixodes ricinus (n = 95), Haemaphysalis punctata (n = 53), Dermacentor reticulatus (n = 2), and Dermacentor marginatus (n = 1); 222 engorged ticks: I. ricinus (n = 164), I. hexagonus (n = 36), H. punctata (n = 16), H. concinna (n = 6), and 70 tissue samples collected from wildlife hosts during 2018 in five urban, and two peri-urban sites. Using a pre-designed Fluidigm real-time PCR dynamic array, all DNA samples were individually screened for the presence of 44 vector-borne pathogens. Subsequently, conventional PCRs were performed for a selection of samples to allow validation and sequencing. In total, 15 pathogens were identified to species and 6 to genus level. In questing ticks, single infections were more common than co-infections. Seven Borrelia spp. were detected in questing I. ricinus, and three in H. punctata ticks. An overall high prevalence 26.35% (95% CI: 19.46–34.22) and diversity of Borrelia burgdorferi sensu lato was seen in urban questing ticks. Other pathogens of the order Rickettsiales were present with variable prevalence. Co-infections occurred in 27.4% (95% CI: 18.72-37.48) of all infected questing ticks. In engorged ticks the overall Bo. burgdorferi sensu lato prevalence was 35.6% (95% CI: 29.29–42.27), with five species present. Pathogens of the order Rickettsiales were also frequently detected. We report for the first time in Romania the presence of Rickettsia aeschlimannii and Rickettsia felis. Overall, from the infected engorged ticks, 69.2% showcased co-infections. In Ixodes spp., dual co-infections, namely Borrelia spp. and Anaplasma phagocytophilum, and Rickettsia helvetica and A. phagocytophilum were the most prevalent. Given the outcome, we underline the need to establish proper tick-surveillance programs in cities and include co-infections in the management plan of tick-borne diseases in Romania.
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Affiliation(s)
- Silvia-Diana Borşan
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Angela Monica Ionică
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania.,"Regele Mihai I al României" Life Sciences Institute, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Clémence Galon
- UMR BIPAR, Animal Health Laboratory, ANSES, INRAE, Ecole Nationale Vétérinaire d'Alfort, Paris-Est Sup, Maisons-Alfort, France
| | - Andra Toma-Naic
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Cosmin Peştean
- Department of Surgery, Anesthesiology and Intensive Therapy, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Attila D Sándor
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania.,Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
| | - Sara Moutailler
- UMR BIPAR, Animal Health Laboratory, ANSES, INRAE, Ecole Nationale Vétérinaire d'Alfort, Paris-Est Sup, Maisons-Alfort, France
| | - Andrei Daniel Mihalca
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
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Rose I, Yoshimizu MH, Bonilla DL, Fedorova N, Lane RS, Padgett KA. Phylogeography of Borrelia spirochetes in Ixodes pacificus and Ixodes spinipalpis ticks highlights differential acarological risk of tick-borne disease transmission in northern versus southern California. PLoS One 2019; 14:e0214726. [PMID: 30946767 PMCID: PMC6448939 DOI: 10.1371/journal.pone.0214726] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 03/19/2019] [Indexed: 12/31/2022] Open
Abstract
The common human-biting tick, Ixodes pacificus, is the primary vector of the Lyme disease spirochete, Borrelia burgdorferi sensu stricto (ss) in western North America and has been found to harbor other closely-related spirochetes in the Borrelia burgdorferi sensu lato (sl) complex. Between 2008–2015, 11,066 adult and 3,815 nymphal I. pacificus and five adult and 144 nymphal Ixodes spinpalpis, a commonly collected wildlife tick, were collected from 42 California counties. Borrelia burgdorferi sl was detected in 1.2% and 3.8% I. pacificus adults and nymphs, respectively. Results from this study indicate genetic diversity and geographic structure of B. burgdorferi sl in California I. pacificus ticks, by sequence comparison of the16S rRNA gene, with B. burgdorferi ss, the agent of Lyme disease, found only in I. pacificus collected from the north and central coastal and Sierra Nevada foothill regions; B. burgdorferi ss was not detected in ticks tested from southern California. In contrast, Borrelia bissettiae, a member of the B. burgdorferi sl complex, was detected in both I. pacificus and I. spinipalpis, in the coastal region of both northern and southern California, but was absent from ticks in the Sierra Nevada foothills. In a similar pattern to B. bissettiae, Borrelia americana (a member of the B. burgdorferi sl complex) was detected in a single adult I. pacificus from the north coast and two I. spinipalpis nymphs from south-coastal California. This study highlights that the geographic area of Lyme disease acarological risk in California is the north-central and Sierra Nevada foothill regions of the state with little to no risk in the southern regions of the state.
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Affiliation(s)
- Ian Rose
- California Department of Public Health, Vector-Borne Disease Section, Richmond, CA, United States of America
| | - Melissa Hardstone Yoshimizu
- California Department of Public Health, Vector-Borne Disease Section, Richmond, CA, United States of America
| | - Denise L. Bonilla
- California Department of Public Health, Vector-Borne Disease Section, Richmond, CA, United States of America
| | - Natalia Fedorova
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA, United States of America
| | - Robert S. Lane
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA, United States of America
| | - Kerry A. Padgett
- California Department of Public Health, Vector-Borne Disease Section, Richmond, CA, United States of America
- * E-mail:
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Groshong AM, Blevins JS. Insights into the biology of Borrelia burgdorferi gained through the application of molecular genetics. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:41-143. [PMID: 24377854 DOI: 10.1016/b978-0-12-800262-9.00002-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Borrelia burgdorferi, the vector-borne bacterium that causes Lyme disease, was first identified in 1982. It is known that much of the pathology associated with Lyme borreliosis is due to the spirochete's ability to infect, colonize, disseminate, and survive within the vertebrate host. Early studies aimed at defining the biological contributions of individual genes during infection and transmission were hindered by the lack of adequate tools and techniques for molecular genetic analysis of the spirochete. The development of genetic manipulation techniques, paired with elucidation and annotation of the B. burgdorferi genome sequence, has led to major advancements in our understanding of the virulence factors and the molecular events associated with Lyme disease. Since the dawn of this genetic era of Lyme research, genes required for vector or host adaptation have garnered significant attention and highlighted the central role that these components play in the enzootic cycle of this pathogen. This chapter covers the progress made in the Borrelia field since the application of mutagenesis techniques and how they have allowed researchers to begin ascribing roles to individual genes. Understanding the complex process of adaptation and survival as the spirochete cycles between the tick vector and vertebrate host will lead to the development of more effective diagnostic tools as well as identification of novel therapeutic and vaccine targets. In this chapter, the Borrelia genes are presented in the context of their general biological roles in global gene regulation, motility, cell processes, immune evasion, and colonization/dissemination.
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Affiliation(s)
- Ashley M Groshong
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Jon S Blevins
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
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4
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Borrelia burgdorferi linear plasmid 28-3 confers a selective advantage in an experimental mouse-tick infection model. Infect Immun 2013; 81:2986-96. [PMID: 23753630 DOI: 10.1128/iai.00219-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the bacterium that causes Lyme disease, has a unique segmented genome consisting of numerous linear and circular plasmids and a linear chromosome. Many of these genetic elements have been found to encode factors critical for B. burgdorferi to complete the infectious cycle. However, several plasmids remain poorly characterized, and their roles during infection with B. burgdorferi have not been elucidated. To more fully characterize the role of one of the four 28-kb linear plasmids, lp28-3, we generated strains specifically lacking lp28-3 and assayed the contribution of genes carried by lp28-3 to B. burgdorferi infection. We found that lp28-3 does not carry any genes that are strictly required for infection of a mouse or tick and that lp28-3-deficient spirochetes are competent at causing a disseminated infection. Interestingly, spirochetes containing lp28-3 were at a selective advantage compared to lp28-3-deficient spirochetes when coinjected into a mouse, and this advantage was reflected in the population of spirochetes acquired by feeding ticks. Our data demonstrate that genes carried by lp28-3, although not essential, contribute to the fitness of B. burgdorferi during infection.
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Abstract
Borrelia species of relapsing fever (RF) and Lyme disease (LD) lineages have linear chromosomes and both linear and circular plasmids. Unique to RF species, and little characterized to date, are large linear plasmids of ∼160 kb, or ∼10% of the genome. By a combination of Sanger and next-generation methods, we determined the sequences of large linear plasmids of two New World species: Borrelia hermsii, to completion of its 174-kb length, and B. turicatae, partially to 114 kb of its 150 kb. These sequences were then compared to corresponding sequences of the Old World species B. duttonii and B. recurrentis and to plasmid sequences of LD Borrelia species. The large plasmids were largely colinear, except for their left ends, about 27 kb of which was inverted in New World species. Approximately 60% of the B. hermsii lp174 plasmid sequence was repetitive for 6 types of sequence, and half of its open reading frames encoded hypothetical proteins not discernibly similar to proteins in the database. The central ∼25 kb of all 4 linear plasmids was syntenic for orthologous genes for plasmid maintenance or partitioning in Borrelia species. Of all the sequenced linear and circular plasmids in Borrelia species, the large plasmid's putative partition/replication genes were most similar to those of the 54-kb linear plasmids of LD species. Further evidence for shared ancestry was the observation that two of the hypothetical proteins were predicted to be structurally similar to the LD species' CspA proteins, which are encoded on the 54-kb plasmids.
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Borrelia burgdorferi linear plasmid 38 is dispensable for completion of the mouse-tick infectious cycle. Infect Immun 2011; 79:3510-7. [PMID: 21708994 DOI: 10.1128/iai.05014-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, the causative agent of Lyme disease, exists in a complex enzootic cycle, transiting between its vector, Ixodes ticks, and a diverse range of vertebrate hosts. B. burgdorferi linear plasmid 38 (lp38) contains several genes that are differentially regulated in response to conditions mimicking the tick or mouse environments, suggesting that these plasmid-borne genes may encode proteins important for the B. burgdorferi infectious cycle. Some of these genes encode potential virulence factors, including hypothetical lipoproteins as well as a putative membrane transport system. To characterize the role of lp38 in the B. burgdorferi infectious cycle, we constructed a shuttle vector to selectively displace lp38 from the B. burgdorferi genome and analyzed the resulting clones to confirm the loss of lp38. We found that, in vitro, clones lacking lp38 were similar to isogenic wild-type bacteria, both in growth rate and in antigenic protein production. We analyzed these strains in an experimental mouse-tick infectious cycle, and our results demonstrate that clones lacking lp38 are fully infectious in a mouse, can efficiently colonize the tick vector, and are readily transmitted to a naive host.
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7
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Dai Q, Restrepo BI, Porcella SF, Raffel SJ, Schwan TG, Barbour AG. Antigenic variation by Borrelia hermsii occurs through recombination between extragenic repetitive elements on linear plasmids. Mol Microbiol 2006; 60:1329-43. [PMID: 16796672 PMCID: PMC5614446 DOI: 10.1111/j.1365-2958.2006.05177.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The relapsing fever agent Borrelia hermsii undergoes multiphasic antigenic variation through gene conversion of a unique expression site on a linear plasmid by an archived variable antigen gene. To further characterize this mechanism we assessed the repertoire and organization of archived variable antigen genes by sequencing approximately 85% of plasmids bearing these genes. Most archived genes shared with the expressed gene a
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Affiliation(s)
- Qiyuan Dai
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, California
| | - Blanca I. Restrepo
- Department of Microbiology, University of Texas Health Science Center at San Antonio, Texas
- University of Texas Health Science Center at Houston, School of Public Health Brownsville Regional Campus, Brownsville, Texas
| | - Stephen F. Porcella
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Sandra J. Raffel
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Tom G. Schwan
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Alan G. Barbour
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, California
- Department of Microbiology, University of Texas Health Science Center at San Antonio, Texas
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Li L, Narayan K, Pak E, Pachner AR. Intrathecal antibody production in a mouse model of Lyme neuroborreliosis. J Neuroimmunol 2006; 173:56-68. [PMID: 16387369 DOI: 10.1016/j.jneuroim.2005.11.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 11/21/2005] [Indexed: 12/28/2022]
Abstract
Intrathecal antibody (ITAb) production is a common feature of neurological diseases, yet very little is known about its mechanisms. Because ITAb is prominent in human Lyme neuroborreliosis (LNB), in the present study we established a mouse model of LNB to study ITAb production. We injected different strains of Borrelia burgdorferi into a variety of mouse strains by the intracerebral (i.c.) route to develop the model. Spirochetal infection and ITAb production were identified by complementary methods. This study demonstrates that the mouse model of LNB can be utilized to test hypotheses related to the mechanisms of ITAb production.
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Affiliation(s)
- Libin Li
- Department of Neurosciences, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 S. Orange Ave., Newark, NJ 07103, USA
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9
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Picardeau M, Lobry JR, Hinnebusch BJ. Analyzing DNA strand compositional asymmetry to identify candidate replication origins of Borrelia burgdorferi linear and circular plasmids. Genome Res 2000; 10:1594-604. [PMID: 11042157 PMCID: PMC310945 DOI: 10.1101/gr.124000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Lyme disease agent Borrelia burgdorferi has a genome composed of a linear chromosome and a series of linear and circular plasmids. We previously mapped the oriC of the linear chromosome to the center of the molecule, where a pronounced switch in CG skew occurs. In this study, we analyzed B. burgdorferi plasmid sequences for AT and CG skew in an effort to similarly identify plasmid replication origins. Cumulative skew diagrams of the plasmids suggested that they, like the linear chromosome, replicate bidirectionally from an internal origin. The B. burgdorferi linear chromosome contains homologs to partitioning protein genes soj and spoOJ, which are closely linked to oriC at the minimum cumulative skew point of the 1-Mb molecule. A soj/parA homolog also maps to cumulative skew minima of the B. burgdorferi linear and circular plasmids, further suggesting that these regions contain the replication origin. The heterogeneity in these genes and in the nucleotide sequences of the putative origin regions could account for the mutual compatibility of the multiple DNA elements in B. burgdorferi.
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Affiliation(s)
- M Picardeau
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Laboratory of Human Bacterial Pathogenesis, Hamilton, Montana 59840, USA
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Porcella SF, Fitzpatrick CA, Bono JL. Expression and immunological analysis of the plasmid-borne mlp genes of Borrelia burgdorferi strain B31. Infect Immun 2000; 68:4992-5001. [PMID: 10948116 PMCID: PMC101720 DOI: 10.1128/iai.68.9.4992-5001.2000] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A lipoprotein gene family first identified in Borrelia burgdorferi strain 297, designated 2.9 LP and recently renamed mlp, was found on circular and linear plasmids in the genome sequence of B. burgdorferi strain B31-M1. Sequence analyses of the B31 mlp genes and physically linked variant gene families indicated that mlp gene heterogeneity is unique and unrelated to location or linkage to divergent sequences. Evidence of recombination between B31 mlp alleles was also detected. Northern blot analysis of cultured strain B31 indicated that the mlp genes were not expressed at a temperature (23 degrees C) characteristic of that of ticks in the environment. In striking contrast, expression of many mlp genes increased substantially when strain B31 was shifted to 35 degrees C, a temperature change mimicking that occurring in the natural transmission cycle of the spirochete from tick to mammal. Primer extension analysis of the mlp mRNA transcripts suggested that sigma 70-like promoters are involved in mlp expression during temperature shift conditions. Antibodies were made against strain B31 Mlp proteins within the first 4 weeks after experimental mouse infection. Importantly, Lyme disease patients also had serum antibodies reactive with purified recombinant Mlp proteins from strain B31, a result indicating that humans are exposed to Mlp proteins during infection. Taken together, the data indicate that strain B31 mlp genes encode a diverse array of lipoproteins which may participate in early infection processes in the mammalian host.
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Affiliation(s)
- S F Porcella
- Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA.
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11
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Abstract
Plasmids encode partitioning genes (par) that are required for faithful plasmid segregation at cell division. Initially, par loci were identified on plasmids, but more recently they were also found on bacterial chromosomes. We present here a phylogenetic analysis of par loci from plasmids and chromosomes from prokaryotic organisms. All known plasmid-encoded par loci specify three components: a cis-acting centromere-like site and two trans-acting proteins that form a nucleoprotein complex at the centromere (i.e. the partition complex). The proteins are encoded by two genes in an operon that is autoregulated by the par-encoded proteins. In all cases, the upstream gene encodes an ATPase that is essential for partitioning. Recent cytological analyses indicate that the ATPases function as adaptors between a host-encoded component and the partition complex and thereby tether plasmids and chromosomal origin regions to specific subcellular sites (i.e. the poles or quarter-cell positions). Two types of partitioning ATPases are known: the Walker-type ATPases encoded by the par/sop gene family (type I partitioning loci) and the actin-like ATPase encoded by the par locus of plasmid R1 (type II partitioning locus). A phylogenetic analysis of the large family of Walker type of partitioning ATPases yielded a surprising pattern: most of the plasmid-encoded ATPases clustered into distinct subgroups. Surprisingly, however, the par loci encoding these distinct subgroups have different genetic organizations and thus divide the type I loci into types Ia and Ib. A second surprise was that almost all chromosome-encoded ATPases, including members from both Gram-negative and Gram-positive Bacteria and Archaea, clustered into one distinct subgroup. The phylogenetic tree is consistent with lateral gene transfer between Bacteria and Archaea. Using database mining with the ParM ATPase of plasmid R1, we identified a new par gene family from enteric bacteria. These type II loci, which encode ATPases of the actin type, have a genetic organization similar to that of type Ib loci.
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Affiliation(s)
- K Gerdes
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense University, Campusvej 55, DK-5230 Odense M,
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Hayes F. The partition system of multidrug resistance plasmid TP228 includes a novel protein that epitomizes an evolutionarily distinct subgroup of the ParA superfamily. Mol Microbiol 2000; 37:528-41. [PMID: 10931346 DOI: 10.1046/j.1365-2958.2000.02030.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The segregational stability of bacterial, low-copy-number plasmids is promoted primarily by active partition. The plasmid-specified components of the prototypical P1 plasmid partition system consist of two proteins, ParA (44.3 kDa) and ParB (38.5 kDa), which, in conjunction with integration host factor, form a nucleoprotein complex at the plasmid partition site, parS. This complex is the probable substrate for the directed temporal and spatial intracellular movement of plasmids before cell division. The genetic organization of the partition cassette of the multidrug resistance plasmid TP228 differs markedly from that of the P1 paradigm. The TP228 system includes a novel member (ParF; 22.0 kDa) of the ParA superfamily of ATPases, of which the P1 ParA protein is the archetype. However, the ParF protein and its immediate relatives form a discrete subgroup of the ParA superfamily, which evolutionarily is more related to the MinD subgroup of cell division proteins than to ParA of P1. The TP228 and P1 partition modules differ further in that the former does not include a parB homologue, but does specify a protein (ParG; 8.6 kDa) unrelated to ParB. Homologues of the parF gene are widely disseminated on eubacterial genomes, suggesting that ParF-mediated partition may be a common mechanism by which plasmid segregational stability is achieved.
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Affiliation(s)
- F Hayes
- Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology (UMIST), PO Box 88, Manchester M60 1QD, UK.
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Stevenson B, Porcella SF, Oie KL, Fitzpatrick CA, Raffel SJ, Lubke L, Schrumpf ME, Schwan TG. The relapsing fever spirochete Borrelia hermsii contains multiple, antigen-encoding circular plasmids that are homologous to the cp32 plasmids of Lyme disease spirochetes. Infect Immun 2000; 68:3900-8. [PMID: 10858201 PMCID: PMC101665 DOI: 10.1128/iai.68.7.3900-3908.2000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. Sequencing of a DNA library constructed from circular plasmid fragments enabled assembly of a composite DNA sequence that is homologous to the cp32 plasmid family of the Lyme disease spirochete, B. burgdorferi. Analysis of another relapsing fever bacterium, B. parkeri, indicated that it contains linear homologs of the B. hermsii and B. burgdorferi cp32 plasmids. The B. hermsii cp32 plasmids encode homologs of the B. burgdorferi Mlp and Bdr antigenic proteins and BlyA/BlyB putative hemolysins, but homologs of B. burgdorferi erp genes were absent. Immunoblot analyses demonstrated that relapsing fever patients produced antibodies to Mlp proteins, indicating that those proteins are synthesized by the spirochetes during human infection. Conservation of cp32-encoded genes in different Borrelia species suggests that their protein products serve functions essential to both relapsing fever and Lyme disease spirochetes. Relapsing fever borreliae replicate to high levels in the blood of infected animals, permitting direct detection and possible functional studies of Mlp, Bdr, BlyA/BlyB, and other cp32-encoded proteins in vivo.
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Affiliation(s)
- B Stevenson
- Department of Microbiology and Immunology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-0298, USA.
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14
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Abstract
Partition cassettes, essential for the segregational stability of low-copy-number bacterial plasmids, typically encode two autoregulated proteins and an adjacent cis-acting centromere analog to which one or perhaps both proteins bind. The diminutive partition region of pTAR of Agrobacterium spp. was reported to be exceptional, encoding only a single protein, ParA (D. R. Gallie and C. I. Kado, J. Mol. Biol. 193:465-478, 1987). However, resequencing of the region revealed two small downstream genes, parB and orf-84, of which only parB was found to be essential for partitioning in A. tumefaciens. Purified ParA exhibited a weak ATPase activity that was modestly increased by nonspecific DNA. ParB bound in vitro to repeated sequences present in a region, parS, that possesses centromere and operator functions and within which we identified the primary transcription start site by primer extension. In certain respects the Par proteins behave normally in the foreign host Escherichia coli. In E. coli, as in A. tumefaciens, ParB repressed the partition operon; ParA, inactive alone, augmented this repression. Functional similarities between the partition system of pTAR and those of other plasmids and bacteria are prominent, despite differences in size, organization, and amino acid sequence.
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Affiliation(s)
- K Kalnin
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892-4255, USA
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15
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Caimano MJ, Yang X, Popova TG, Clawson ML, Akins DR, Norgard MV, Radolf JD. Molecular and evolutionary characterization of the cp32/18 family of supercoiled plasmids in Borrelia burgdorferi 297. Infect Immun 2000; 68:1574-86. [PMID: 10678977 PMCID: PMC97318 DOI: 10.1128/iai.68.3.1574-1586.2000] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/1999] [Accepted: 11/26/1999] [Indexed: 11/20/2022] Open
Abstract
In this study, we characterized seven members of the cp32/18 family of supercoiled plasmids in Borrelia burgdorferi 297. Complete sequence analysis of a 21-kb plasmid (cp18-2) confirmed that the strain 297 plasmids are similar in overall content and organization to their B31 counterparts. Of the 31 open reading frames (ORFs) in cp18-2, only three showed sequence relatedness to proteins with known functions, and only one, a ParA/SopA ortholog, was related to nonborrelial polypeptides. Besides the lipoproteins, none of the ORFs appeared likely to encode a surface-exposed protein. Comparison with the B31 genomic sequence indicated that paralogs for most of the ORFs in cp18-2 can be identified on other genetic elements. cp18-2 was found to lack a 9- to 10-kb fragment present in the 32-kb homologs which, by extrapolation from the B31 cp32 sequences, contains at least 15 genes presumed to be unnecessary for plasmid maintenance. Sequence analysis of the lipoprotein-encoding variable loci provided evidence that recombinatorial processes within these regions may result in the acquisition of exogenous DNA. Pairwise analysis with random shuffling revealed that the multiple lipoproteins (Mlp; formerly designated 2.9 LPs) fall into two distinct homology groups which appear to have arisen by gene fusion events similar to those recently proposed to have generated the three OspE, OspF, and Elp lipoprotein families (D. R. Akins, M. J. Caimano, X. Yang, F. Cerna, M. V. Norgard, and J. D. Radolf, Infect. Immun. 67:1526-1532, 1999). Comparative analysis of the variable regions also indicated that recombination within the loci of each plasmid may occur independently. Last, comparison of variable loci revealed that the cp32/18 plasmid complements of the B31 and 297 isolates differ substantially, indicating that the two strains have been subject to divergent adaptive pressures. In addition to providing evidence for two different types of recombinatorial events involving cp32/18 plasmids, these findings underscore the need for genetic analysis of diverse borrelial isolates in order to elucidate the Lyme disease spirochete's complex parasitic strategies.
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Affiliation(s)
- M J Caimano
- Center for Microbial Pathogenesis, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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16
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Casjens S, Palmer N, van Vugt R, Huang WM, Stevenson B, Rosa P, Lathigra R, Sutton G, Peterson J, Dodson RJ, Haft D, Hickey E, Gwinn M, White O, Fraser CM. A bacterial genome in flux: the twelve linear and nine circular extrachromosomal DNAs in an infectious isolate of the Lyme disease spirochete Borrelia burgdorferi. Mol Microbiol 2000; 35:490-516. [PMID: 10672174 DOI: 10.1046/j.1365-2958.2000.01698.x] [Citation(s) in RCA: 598] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have determined that Borrelia burgdorferi strain B31 MI carries 21 extrachromosomal DNA elements, the largest number known for any bacterium. Among these are 12 linear and nine circular plasmids, whose sequences total 610 694 bp. We report here the nucleotide sequence of three linear and seven circular plasmids (comprising 290 546 bp) in this infectious isolate. This completes the genome sequencing project for this organism; its genome size is 1 521 419 bp (plus about 2000 bp of undetermined telomeric sequences). Analysis of the sequence implies that there has been extensive and sometimes rather recent DNA rearrangement among a number of the linear plasmids. Many of these events appear to have been mediated by recombinational processes that formed duplications. These many regions of similarity are reflected in the fact that most plasmid genes are members of one of the genome's 161 paralogous gene families; 107 of these gene families, which vary in size from two to 41 members, contain at least one plasmid gene. These rearrangements appear to have contributed to a surprisingly large number of apparently non-functional pseudogenes, a very unusual feature for a prokaryotic genome. The presence of these damaged genes suggests that some of the plasmids may be in a period of rapid evolution. The sequence predicts 535 plasmid genes >/=300 bp in length that may be intact and 167 apparently mutationally damaged and/or unexpressed genes (pseudogenes). The large majority, over 90%, of genes on these plasmids have no convincing similarity to genes outside Borrelia, suggesting that they perform specialized functions.
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Affiliation(s)
- S Casjens
- Division of Molecular Biology and Genetics, Department of Oncological Sciences, University of Utah Medical School, Salt Lake City, UT 84132, USA
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17
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Marconi RT, Hohenberger S, Jauris-Heipke S, Schulte-Spechtel U, LaVoie CP, Rössler D, Wilske B. Genetic analysis of Borrelia garinii OspA serotype 4 strains associated with neuroborreliosis: evidence for extensive genetic homogeneity. J Clin Microbiol 2000; 37:3965-70. [PMID: 10565915 PMCID: PMC85856 DOI: 10.1128/jcm.37.12.3965-3970.1999] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection with Borrelia garinii outer surface protein (Osp) A serotype 4 strains has been correlated with the development of neuroborreliosis in Lyme borreliosis patients in Europe. OspA serotype 4 isolates have been recovered primarily from human cerebrospinal fluid, suggesting a tropism for this environment. Previous studies with monoclonal antibodies directed against OspA and OspC demonstrated that OspA serotype 4 strains are antigenically closely related. In view of the pronounced antigenic and genetic variability that has been noted in the Osps of other Borrelia isolates, we sought to determine if OspA serotype 4 strains represent a recently emerged clonal lineage of B. garinii. Toward this goal, a representative group of OspA serotype 4 strains was analyzed for traits that typically exhibit hypervariability among isolates that cause Lyme borreliosis. The following criteria were assessed: (i) ospC sequences, (ii) plasmid composition, (iii) genomic restriction fragment length polymorphism (RFLP) patterns, and (iv) the RFLP patterns of the upstream homology box (UHB) element which flanks members of the UHB gene family at their 5' end. Collectively, these analyses demonstrate genetic homogeneity, suggesting that OspA serotype 4 strains are a recently emerged clonal lineage with an apparent tropism for the central nervous system.
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Affiliation(s)
- R T Marconi
- Medical College of Virginia at Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA
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18
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Zückert WR, Meyer J, Barbour AG. Comparative analysis and immunological characterization of the Borrelia Bdr protein family. Infect Immun 1999; 67:3257-66. [PMID: 10377099 PMCID: PMC116504 DOI: 10.1128/iai.67.7.3257-3266.1999] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/1999] [Accepted: 04/12/1999] [Indexed: 11/20/2022] Open
Abstract
Multiple circular and linear plasmids of Lyme disease and relapsing fever Borrelia spirochetes carry genes for members of the Bdr (Borrelia direct repeat) protein family. To define their common and divergent attributes, we first comprehensively compared the known homologs. Bdr proteins with predicted sizes ranging from 10.7 to 30. 6 kDa formed five homology groups, based on variable numbers of short direct repeats in a central domain and diverse N- and C-terminal domains. In a further characterization, Western blots were probed with rabbit antisera raised against either of two purified recombinant Bdr proteins from Borrelia burgdorferi B31. The results showed that antibodies cross-react and several Bdr paralogs 19.5 to 30.5 kDa in size are expressed by cultured strain B31 in a temperature-independent manner. In situ proteolysis, immunofluorescence, and growth inhibition assays indicated that Bdr proteins are not surface exposed. Distinct patterns of cross-reacting proteins of 17.5 to 33 kDa were also detected in other B. burgdorferi, Borrelia garinii, and Borrelia afzelii strains as well as in relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae. Last, we examined whether these proteins are antibody targets during Lyme disease. Analysis of 47 Lyme disease patient sera by immunoblotting and enzyme-linked immunosorbent assays showed that 24 (51%) and 20 (43%), respectively, had detectable antibodies to one or more of the Bdr proteins. Together, these data indicate that Bdr proteins constitute a family of cross-reactive Borrelia proteins which are expressed in the course of Lyme disease and in vitro.
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Affiliation(s)
- W R Zückert
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, California 92697, USA
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19
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Rosa P, Stevenson B, Tilly K. 7 Genetic Methods in Borrelia and Other Spirochaetes. METHODS IN MICROBIOLOGY 1999. [DOI: 10.1016/s0580-9517(08)70118-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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20
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Tilly K, Lubke L, Rosa P. Characterization of circular plasmid dimers in Borrelia burgdorferi. J Bacteriol 1998; 180:5676-81. [PMID: 9791118 PMCID: PMC107627 DOI: 10.1128/jb.180.21.5676-5681.1998] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/1998] [Accepted: 08/26/1998] [Indexed: 11/20/2022] Open
Abstract
We have inactivated the ospC, oppAIV, and guaB genes on the 26-kb circular plasmid of Borrelia burgdorferi (cp26) by allelic exchange. On several occasions following such transformations, the cp26 of transformants had an aberrant mobility through agarose gels. Characterization of these cp26 molecules showed that the plasmid had dimerized. These dimers were quite stable during either selective or nonselective passage. Subsequent transformations with dimer DNA supported the hypothesis that in B. burgdorferi, transforming cp26 DNA most likely does not displace the resident homologous plasmid but rather must recombine in order to donate sequences that it carries. These serendipitous findings provide a mechanism for obtaining heterozygous complemented control strains when mutant phenotypes are characterized.
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Affiliation(s)
- K Tilly
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA.
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21
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Polo S, Guerini O, Sosio M, Dehb G. Identification of two linear plasmids in the actinomycete Planobispora rosea. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 10):2819-2825. [PMID: 9802023 DOI: 10.1099/00221287-144-10-2819] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two linear plasmids (pPR1, 27.5 kb, and pPR2, 16 kb) were identified in Planobispora rosea, an actinomycete that produces the antibiotic GE2270, an inhibitor of the elongation factor Tu. Strains lacking both plasmids still produce and are resistant to GE2270. The two plasmids share an internal region of high similarity, but no cross-hybridization was detected between their telomeric regions or between plasmid and chromosomal DNA. The 5' ends of the plasmids appear to be linked to terminal proteins. The telomeric regions of pPR2 were cloned after 3'-end homopolymer tailing and PCR amplification. The approximately 650 nt telomeric DNA sequences of pPR2 are repeated in inverted orientation and are rich in direct and inverted repeats; the 350 bp terminal region is less G + C-rich than the rest of the plasmid. The structural organization of these plasmids appears to be similar to Streptomyces linear replicons.
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Affiliation(s)
- Simona Polo
- Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly
| | - Oscar Guerini
- Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly
| | | | - Gianni Dehb
- Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly
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22
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Sung SY, Lavoie CP, Carlyon JA, Marconi RT. Genetic divergence and evolutionary instability in ospE-related members of the upstream homology box gene family in Borrelia burgdorferi sensu lato complex isolates. Infect Immun 1998; 66:4656-68. [PMID: 9746562 PMCID: PMC108573 DOI: 10.1128/iai.66.10.4656-4668.1998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/1998] [Accepted: 07/10/1998] [Indexed: 11/20/2022] Open
Abstract
A series of related genes that are flanked at their 5' ends by a conserved upstream sequence element called the upstream homology box (UHB) have been identified in Borrelia burgdorferi. These genes have been referred to as the UHB or erp gene family. We previously demonstrated that among a limited number of B. burgdorferi isolates, the UHB gene family is variable in composition and organization. Prior to this report the UHB gene family in other species of the B. burgdorferi sensu lato complex had not been studied, and if this family is important in the pathogenesis or biology of the Lyme disease spirochetes, then a wide distribution among species and isolates of the B. burgdorferi sensu lato complex would be expected. To assess this, we screened for the UHB element by Southern hybridization and determined its restriction fragment length polymorphism (RFLP) patterns. The UHB element was found to be carried by all B. burgdorferi sensu lato complex species tested (B. burgdorferi, B. garinii, B. afzelii, B. japonica, B. valaisiana sp. nov., and B. andersonii), but the RFLP patterns varied widely at both the inter- and intraspecies levels. Variation in both the number and size of the hybridizing restriction fragments was evident. PCR analyses also revealed the presence of polymorphic, ospE-related alleles in many isolates. Sequence analyses identified the molecular basis of the polymorphisms as being primarily insertions and deletions. Sequence variation and the insertions and deletions were found to be clustered in two distinct domains (variable domains 1 and 2). In many isolates variable domain 1 is flanked by direct repeat elements, some as long as 38 bp. Computer analyses of the deduced amino acid sequences encoded within variable domain 1 predict them to be hydrophilic, surface exposed, and antigenic. The analyses conducted here suggest that the UHB gene family, as evidenced by the variable UHB RFLP patterns, is not evolutionarily stable and that the polymorphic ospE alleles are derived from a common ancestral gene which has been modified through mutation or recombination events. The characterization of ospE-related genes of the UHB gene family among B. burgdorferi sensu lato species will prove important in attempts to construct a model for UHB gene family organization and in deciphering the role of the UHB gene family in the biology and pathogenesis of the Lyme disease spirochetes.
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Affiliation(s)
- S Y Sung
- Department of Microbiology and Immunology, Medical College of Virginia of Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA
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23
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Stevenson B, Casjens S, Rosa P. Evidence of past recombination events among the genes encoding the Erp antigens of Borrelia burgdorferi. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 7):1869-1879. [PMID: 9695920 DOI: 10.1099/00221287-144-7-1869] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A single Borrelia burgdorferi bacterium may contain six or more different 32 kb circular plasmids (cp32s). Although these plasmids are homologous throughout much of their sequences, two loci have been identified at which they can vary significantly. The cp32 plasmids and their relatives each contain two adjacent genes, orfC and orf3, that vary in sequence between plasmids found within clones of individual bacteria. The orfC gene product is homologous to proteins involved in partitioning of bacterial plasmids, and the differences at this locus between plasmids may account for their compatibility. The orfC-orf3 loci are located approximately 5 kb from another variable locus called erp. The orfC-orf3 loci were used as physically linked markers to assess genetic rearrangements in the erp loci; this revealed examples of recombination involving both individual genes and entire erp loci. Recombination of the genes encoding the Erp antigens might contribute to the evasion of the mammalian immune response and could play roles in the establishment and persistence of B. burgdorferi infections in mammalian hosts.
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Affiliation(s)
- Brian Stevenson
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious DiseasesNIH, Hamilton, MT 59840USA
| | - Sherwood Casjens
- Division of Molecular Biology and Genetics, Department of Oncological Sciences, University of UtahSalt Lake City, UT 84132USA
| | - Patricia Rosa
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious DiseasesNIH, Hamilton, MT 59840USA
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24
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Carlyon JA, LaVoie C, Sung SY, Marconi RT. Analysis of the organization of multicopy linear- and circular-plasmid-carried open reading frames in Borrelia burgdorferi sensu lato isolates. Infect Immun 1998; 66:1149-58. [PMID: 9488408 PMCID: PMC108028 DOI: 10.1128/iai.66.3.1149-1158.1998] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/1997] [Accepted: 12/31/1997] [Indexed: 02/06/2023] Open
Abstract
Plasmid cp8.3 of Borrelia afzelii IP21 carries several open reading frames (ORFs) and a 184-bp inverted repeat (IR) element. It has been speculated that this plasmid may encode factors involved in virulence or infectivity. In this report, we have characterized the distribution, molecular variability, and organization of ORFs 1, 2, and 4 and the IR elements among isolates of the Borrelia burgdorferi sensu lato complex. ORFs 1 and 2 are contained within a segment of cp8.3 that is bordered by the IR elements, while ORF 4 resides just outside of the IR-bordered region. By PCR, ORF 4 was amplified from most isolates while ORFs 1 and 2 were amplified from only some B. afzelii isolates. However, Southern hybridization analyses with ORF 1, 2, and 4 probes detected related sequences even in some isolates that were PCR negative. The ORF restriction fragment length polymorphism patterns varied widely even among isolates of the same species. Two-dimensional contour-clamped homogeneous electric field-pulsed-field gel electrophoresis and Southern hybridization detected ORF 1-, 2-, and 4-related sequences on linear and circular plasmids. In addition, an ORF 4-related sequence was detected on a previously uncharacterized, circular plasmid that is greater than 70 kb in size. The IR elements originally identified on plasmid cp8.3 of B. afzelii IP21 were also analyzed by Southern hybridization. Related sequences were detected in some but not all B. burgdorferi sensu lato isolates. These sequences are carried on plasmids in addition to cp8.3 in some isolates. Single-primer PCR analyses demonstrated that in some isolates these sequences exist with IR orientation. The data presented here demonstrate that the IR elements and the ORF 1-, 2-, and 4-related sequences are multicopy and are variable in organization and in genomic location among isolates of the B. burgdorferi sensu lato complex. These analyses provide additional evidence for the highly variable organization of the plasmid component of the B. burgdorferi sensu lato genome.
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Affiliation(s)
- J A Carlyon
- Department of Microbiology and Immunology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0678, USA
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25
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Fraser CM, Casjens S, Huang WM, Sutton GG, Clayton R, Lathigra R, White O, Ketchum KA, Dodson R, Hickey EK, Gwinn M, Dougherty B, Tomb JF, Fleischmann RD, Richardson D, Peterson J, Kerlavage AR, Quackenbush J, Salzberg S, Hanson M, van Vugt R, Palmer N, Adams MD, Gocayne J, Weidman J, Utterback T, Watthey L, McDonald L, Artiach P, Bowman C, Garland S, Fuji C, Cotton MD, Horst K, Roberts K, Hatch B, Smith HO, Venter JC. Genomic sequence of a Lyme disease spirochaete, Borrelia burgdorferi. Nature 1997; 390:580-6. [PMID: 9403685 DOI: 10.1038/37551] [Citation(s) in RCA: 1508] [Impact Index Per Article: 55.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The genome of the bacterium Borrelia burgdorferi B31, the aetiologic agent of Lyme disease, contains a linear chromosome of 910,725 base pairs and at least 17 linear and circular plasmids with a combined size of more than 533,000 base pairs. The chromosome contains 853 genes encoding a basic set of proteins for DNA replication, transcription, translation, solute transport and energy metabolism, but, like Mycoplasma genitalium, it contains no genes for cellular biosynthetic reactions. Because B. burgdorferi and M. genitalium are distantly related eubacteria, we suggest that their limited metabolic capacities reflect convergent evolution by gene loss from more metabolically competent progenitors. Of 430 genes on 11 plasmids, most have no known biological function; 39% of plasmid genes are paralogues that form 47 gene families. The biological significance of the multiple plasmid-encoded genes is not clear, although they may be involved in antigenic variation or immune evasion.
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Affiliation(s)
- C M Fraser
- Institute for Genomic Research, Rockville, Maryland 20850, USA
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26
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Wang J, Masuzawa T, Li M, Yanagihara Y. An unusual illegitimate recombination occurs in the linear-plasmid-encoded outer-surface protein A gene of Borrelia afzelii. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 12):3819-3825. [PMID: 9421906 DOI: 10.1099/00221287-143-12-3819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this study, we describe an unusual illegitimate recombination in the linear-plasmid-encoded outer-surface protein A gene of Borrelia afzelii. A 96 bp DNA segment was deleted from the ospA structural gene of B. afzelii strain R9. The nature of the rearrangement suggested that it arose by a strand slippage mechanism, which was stimulated by a 18-mer palindromic sequence and 5-mer short direct repeats at both termini of the deleted DNA. The deleted sequence could form a complex hairpin structure suggesting that it may have played important roles in pausing of replication and slippaging of the nascent strand across the replication fork. In addition, the mutant strain was isolated from a chronic Lyme disease patient, implying that the variation mechanism may have been used by the borrelial strain to avoid host immune elimination.
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Affiliation(s)
- Jianhui Wang
- Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka 52-1 Yada, Shizuoka 422 Japan
| | - Toshiyuki Masuzawa
- Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka 52-1 Yada, Shizuoka 422 Japan
| | - Muqing Li
- Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka 52-1 Yada, Shizuoka 422 Japan
| | - Yasutake Yanagihara
- Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka 52-1 Yada, Shizuoka 422 Japan
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Cadavid D, Pennington PM, Kerentseva TA, Bergström S, Barbour AG. Immunologic and genetic analyses of VmpA of a neurotropic strain of Borrelia turicatae. Infect Immun 1997; 65:3352-60. [PMID: 9234797 PMCID: PMC175474 DOI: 10.1128/iai.65.8.3352-3360.1997] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In mice infected with serotype A but not serotype B of the relapsing fever spirochete Borrelia turicatae, early invasion of the brain occurs. Serotypes A and B are further distinguished by the abundant surface protein they produce: VmpA and VmpB, respectively. Western blotting with monoclonal antibodies, one-dimensional peptide mapping, and partial amino acid sequencing demonstrated regions of the VmpA protein that differed from VmpB. Oligonucleotide primers based on the partial amino acid sequences of unique regions were used to amplify a portion of the VmpA gene (vmpA) by PCR, and the product was used as a probe in Southern blot and Northern blot analyses. These experiments showed that (i) expression of the vmpA sequence was determined at the level of transcription and (ii) the vmpA sequence was in two locations in serotype A and one location in serotype B. The vmpA gene at the expression-linked locus of serotype A was cloned and sequenced. An open reading frame would encode a polypeptide of 214 amino acids. The polypeptide expressed by Escherichia coli was bound by VmA-specific but not VmpB-specific antibody. Primer extension analysis identified a consensus sigma70-type promoter for vmpA at the expression locus. Phylogenetic analysis revealed that VmpA is homologous to small Vmp (Vsp) proteins of B. hermsii and to OspC proteins of B. burgdorferi. These findings indicate that a function of the Vsp-OspC family of proteins of Borrelia spp. may be differential localization in organs, including the brain, during infection.
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Affiliation(s)
- D Cadavid
- Department of Microbiology, University of Texas Health Science Center at San Antonio, 78284, USA
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