Intact O-antigen is critical structure for the exceptional tubular shape of outer membrane vesicles in Francisella tularensis.

Francisella tularensis is a highly infectious Gram-negative coccobacillus which causes the disease tularemia. The potential for its misuse as a biological weapon has led disease control and prevention centers to classify this bacterium as a category A agent. Bacterial outer membrane vesicles (OMVs) are spherical particles 20-250 nm in size produced by all Gram-negative bacteria and constitute one of the major secretory pathways.

Utilization of a tetracycline-inducible system for high-level expression of recombinant proteins in Francisella tularensis LVS.

Francisella tularensis is a Gram-negative intracellular pathogen causing tularemia. A number of its potential virulence factors have been identified, but their biology and functions are not precisely known. Understanding the biological and immunological functions of these proteins requires adequate genetic tools for homologous and heterologous expression of cloned genes, maintaining both original structure and post-translational modifications.

Inactivation of Francisella tularensis Gene Encoding Putative ABC Transporter Has a Pleiotropic Effect upon Production of Various Glycoconjugates.

Francisella tularensis, an intracellular pathogen causing the disease tularemia, utilizes surface glycoconjugates such as lipopolysaccharide, capsule, and capsule-like complex for its protection against inhospitable conditions of the environment. Francisella species also possess a functional glycosylation apparatus by which specific proteins are O-glycosidically modified. We here created a mutant with a nonfunctional FTS_1402 gene encoding for a putative glycan flippase and studied the consequences of its disruption.

Characterization of tetratricopeptide repeat-like proteins in Francisella tularensis and identification of a novel locus required for virulence.

Francisella tularensis is a highly infectious bacterium that causes the potentially lethal disease tularemia. This extremely virulent bacterium is able to replicate in the cytosolic compartments of infected macrophages. To invade macrophages and to cope with their intracellular environment, Francisella requires multiple virulence factors, which are still being identified.

Specific antibodies protect gamma-irradiated mice against Francisella tularensis infection.

The role of antibodies in the course of Francisella tularensis (F. tularensis) infection is still a subject of debate. The understanding of the poorly described role of humoral immunity is more than important for the effort to develop effective prophylactic procedure against the infection with Francisella virulent strains.

Use of magnetic hydrazide-modified polymer microspheres for enrichment of glycoproteins.

The field of microbial proteomics has currently experienced a boom in the discovery of glycosylated proteins of various pathogenic bacteria as potential mediators of host-pathogen interactions. The presence of glycoproteins has recently been discovered in a Gram-negative pathogenic bacterium , utilizing glycoprotein detection and isolation techniques in combination with mass spectrometry. The isolation of glycoproteins is a prerequisite for their subsequent mass-spectrometric identification.

Characterization of protein glycosylation in Francisella tularensis subsp. holarctica: identification of a novel glycosylated lipoprotein required for virulence.

FTH_0069 is a previously uncharacterized strongly immunoreactive protein that has been proposed to be a novel virulence factor in Francisella tularensis. Here, the glycan structure modifying two C-terminal peptides of FTH_0069 was identified utilizing high resolution, high mass accuracy mass spectrometry, combined with in-source CID tandem MS experiments. The glycan observed at m/z 1156 was determined to be a hexasaccharide, consisting of two hexoses, three N-acetylhexosamines, and an unknown monosaccharide containing a phosphate group.

Multimethodological approach to identification of glycoproteins from the proteome of Francisella tularensis, an intracellular microorganism.

It appears that most glycoproteins found in pathogenic bacteria are associated with virulence. Despite the recent identification of novel virulence factors, the mechanisms of virulence in Francisella tularensis are poorly understood. In spite of its importance, questions about glycosylation of proteins in this bacterium and its potential connection with bacterial virulence have not been answered yet.

Bioanalytical tools for the discovery of eukaryotic glycoproteins applied to the analysis of bacterial glycoproteins.

The commonly accepted theory that prokaryotes lack the ability to glycosylate their proteins has been disproved recently. The field of bacterial glycoprotein research is no longer considered novel owing to the rapid progress in analytical technologies and genome sequencing that has been made in the last few years. Enhanced interest in glycoprotein discovery in bacteria can be explained by a proven correlation between the presence of glycosylation and bacterial pathogenicity.