The phylogeographic pattern of Francisella tularensis in Sweden indicates a Scandinavian origin of Eurosiberian tularaemia.

Previous studies of the causative agent of tularaemia, Francisella tularensis have identified phylogeographic patterns suggestive of environmental maintenance reservoirs. To investigate the phylogeography of tularaemia in Sweden, we selected 163 clinical isolates obtained during 1995-2009 in 10 counties and sequenced one isolate's genome to identify new genetic markers. An improved typing scheme based on two indels and nine SNPs was developed using hydrolysis or TaqMan MGB probe assays.

Genome sequence of Francisella tularensis subspecies holarctica strain FSC200, isolated from a child with tularemia.

Here we report the complete, accurate 1.89-Mb genome sequence of Francisella tularensis subsp. holarctica strain FSC200, isolated in 1998 in the Swedish municipality Ljusdal, which is in an area where tularemia is highly endemic.

Increased knowledge of Francisella genus diversity highlights the benefits of optimised DNA-based assays.

Background: Recent advances in sequencing technologies offer promising tools for generating large numbers of genomes, larger typing databases and improved mapping of environmental bacterial diversity. However, DNA-based methods for the detection of Francisella were developed with limited knowledge about genetic diversity. This, together with the high sequence identity between several Francisella species, means there is a high risk of false identification and detection of the highly virulent pathogen Francisella tularensis.

Genome characterisation of the genus Francisella reveals insight into similar evolutionary paths in pathogens of mammals and fish.

Background: Prior to this study, relatively few strains of Francisella had been genome-sequenced. Previously published Francisella genome sequences were largely restricted to the zoonotic agent F. tularensis.

Whole-genome sequencing reveals distinct mutational patterns in closely related laboratory and naturally propagated Francisella tularensis strains.

The F. tularensis type A strain FSC198 from Slovakia and a second strain FSC043, which has attenuated virulence, are both considered to be derivatives of the North American F. tularensis type A strain SCHU S4.

A real-time PCR array for hierarchical identification of Francisella isolates.

A robust, rapid and flexible real-time PCR assay for hierarchical genetic typing of clinical and environmental isolates of Francisella is presented. Typing markers were found by multiple genome and gene comparisons, from which 23 canonical single nucleotide polymorphisms (canSNPs) and 11 canonical insertion-deletion mutations (canINDELs) were selected to provide phylogenetic guidelines for classification from genus to isolate level. The specificity of the developed assay, which uses 68 wells of a 96-well real-time PCR format with a detection limit of 100 pg DNA, was assessed using 62 Francisella isolates of diverse genetic and geographical origins.

Landscape epidemiology of tularemia outbreaks in Sweden.

Summer outbreaks of tularemia that occurred from 1995 through 2005 in 2 locations in Sweden affected 441 persons. We performed an epidemiologic investigation of these outbreaks using a novel strategy, involving high-resolution genotyping of Francisella tularensis isolates obtained from 136 patients (using 18 genetic markers developed from 6 F. tularensis genome sequences) and interviews with the patients.

Molecular evolutionary consequences of niche restriction in Francisella tularensis, a facultative intracellular pathogen.

Francisella tularensis is a potent mammalian pathogen well adapted to intracellular habitats, whereas F. novicida and F. philomiragia are less virulent in mammals and appear to have less specialized lifecycles.

Canonical insertion-deletion markers for rapid DNA typing of Francisella tularensis.

To develop effective and accurate typing of strains of Francisella tularensis, a potent human pathogen and a putative bioterrorist agent, we combined analysis of insertion-deletion (indel) markers with multiple-locus variable-number tandem repeat analysis (MLVA). From 5 representative F. tularensis genome sequences, 38 indel markers with canonical properties, i.

A 55 kDa hypothetical membrane protein is an iron-regulated virulence factor of Francisella tularensis subsp. novicida U112.

Iron is an important nutritional requirement for bacteria due to its conserved role in many essential metabolic processes. As a consequence of the lack of freely available iron in the mammalian host, bacteria upregulate a range of virulence factors during infection. Transcriptional analysis of Francisella tularensis subsp.

Comparison of Francisella tularensis genomes reveals evolutionary events associated with the emergence of human pathogenic strains.

Background: Francisella tularensis subspecies tularensis and holarctica are pathogenic to humans, whereas the two other subspecies, novicida and mediasiatica, rarely cause disease. To uncover the factors that allow subspecies tularensis and holarctica to be pathogenic to humans, we compared their genome sequences with the genome sequence of Francisella tularensis subspecies novicida U112, which is nonpathogenic to humans.

Results: Comparison of the genomes of human pathogenic Francisella strains with the genome of U112 identifies genes specific to the human pathogenic strains and reveals pseudogenes that previously were unidentified.

Potential source of Francisella tularensis live vaccine strain attenuation determined by genome comparison.

Francisella tularensis is a bacterial pathogen that causes the zoonotic disease tularemia and is important to biodefense. Currently, the only vaccine known to confer protection against tularemia is a specific live vaccine strain (designated LVS) derived from a virulent isolate of Francisella tularensis subsp. holarctica.

Direct repeat-mediated deletion of a type IV pilin gene results in major virulence attenuation of Francisella tularensis.

Francisella tularensis, the causative agent of tularaemia, is a highly infectious and virulent intracellular pathogen. There are two main human pathogenic subspecies, Francisella tularensis ssp. tularensis (type A), and Francisella tularensis ssp.

A mutant of Francisella tularensis strain SCHU S4 lacking the ability to express a 58-kilodalton protein is attenuated for virulence and is an effective live vaccine.

Francisella tularensis subsp. tularensis (type A) strain SCHU S4 is a prototypic strain of the pathogen that is highly virulent for humans and other mammals. Its intradermal (i.

Evolution of subspecies of Francisella tularensis.

Analysis of unidirectional genomic deletion events and single nucleotide variations suggested that the four subspecies of Francisella tularensis have evolved by vertical descent. The analysis indicated an evolutionary scenario where the highly virulent F. tularensis subsp.

The complete genome sequence of Francisella tularensis, the causative agent of tularemia.

Francisella tularensis is one of the most infectious human pathogens known. In the past, both the former Soviet Union and the US had programs to develop weapons containing the bacterium. We report the complete genome sequence of a highly virulent isolate of F.

The crystal structure of the carbohydrate-recognition domain of the glycoprotein sorting receptor p58/ERGIC-53 reveals an unpredicted metal-binding site and conformational changes associated with calcium ion binding.

p58/ERGIC-53 is a calcium-dependent animal lectin that acts as a cargo receptor, binding to a set of glycoproteins in the endoplasmic reticulum (ER) and transporting them to the Golgi complex. It is similar in structure to calcium-dependent leguminous lectins. We have determined the structure of the carbohydrate-recognition domain of p58/ERGIC-53 in its calcium-bound form.

VIPL, a VIP36-like membrane protein with a putative function in the export of glycoproteins from the endoplasmic reticulum.

Subsets of glycoproteins are thought to require lectin-like membrane receptors for efficient export out of the endoplasmic reticulum (ER). To identify new members related to two previously characterized intracellular lectins ERGIC-53/p58 and VIP36, we carried out an extensive database search using the conserved carbohydrate recognition domain (CRD) as a search string. A gene, more closely related to VIP36 than to ERGIC-53/p58, and hence called VIPL (VIP36-Like), was identified.

Expression, purification, refolding and crystallization of the carbohydrate-recognition domain of p58/ERGIC-53, an animal C-type lectin involved in export of glycoproteins from the endoplasmic reticulum.

p58/ERGIC-53 is a mammalian calcium-dependent lectin that serves as a glycoprotein-sorting receptor between the endoplasmic reticulum (ER) and the Golgi complex. It is a type I transmembrane protein with two lumenal domains, one of which is a carbohydrate-recognition domain (CRD) and homologous to leguminous lectins. The CRD of p58, the rat homologue of human ERGIC-53, was overexpressed in insect cells and Escherichia coli, purified and crystallized using Li(2)SO(4) as a precipitant.

Crystal structure of the carbohydrate recognition domain of p58/ERGIC-53, a protein involved in glycoprotein export from the endoplasmic reticulum.

p58/ERGIC-53 is an animal calcium-dependent lectin that cycles between the endoplasmic reticulum (ER) and the Golgi complex and appears to act as a cargo receptor for a subset of soluble glycoproteins exported from the ER. We have determined the crystal structure of the carbohydrate recognition domain (CRD) of p58, the rat homologue of human ERGIC-53, to 1.46 A resolution.