Differential Substrate Usage and Metabolic Fluxes in Subspecies and .

is an intracellular pathogen for many animals causing the infectious disease, tularemia. Whereas subsp. is highly pathogenic for humans, is almost avirulent for humans, but virulent for mice.

Functional Analysis of the Alternative Sigma-28 Factor FliA and Its Anti-Sigma Factor FlgM of the Nonflagellated Legionella Species L. oakridgensis.

causes Legionnaires' disease but is known to be less virulent than is one of the species that is nonflagellated. The genes of the flagellar regulon are absent, except those encoding the alternative sigma-28 factor (FliA) and its anti-sigma-28 factor (FlgM). Similar to , and , located in the same phylogenetic clade, have no flagellar regulon, although both are positive for and Here, we investigated the role and function of both genes to better understand the role of FliA, the positive regulator of flagellin expression, in nonflagellated strains.

Growth-related Metabolism of the Carbon Storage Poly-3-hydroxybutyrate in Legionella pneumophila.

Legionella pneumophila, the causative agent of Legionnaires disease, has a biphasic life cycle with a switch from a replicative to a transmissive phenotype. During the replicative phase, the bacteria grow within host cells in Legionella-containing vacuoles. During the transmissive phenotype and the postexponential (PE) growth phase, the pathogens express virulence factors, become flagellated, and leave the Legionella-containing vacuoles.

Amino Acid Uptake and Metabolism of Legionella pneumophila Hosted by Acanthamoeba castellanii.

Legionella pneumophila survives and replicates within a Legionella-containing vacuole (LCV) of amoebae and macrophages. Less is known about the carbon metabolism of the bacteria within the LCV. We have now analyzed the transfer and usage of amino acids from the natural host organism Acanthamoeba castellanii to Legionella pneumophila under in vivo (LCV) conditions.

Legionella oakridgensis ATCC 33761 genome sequence and phenotypic characterization reveals its replication capacity in amoebae.

Legionella oakridgensis is able to cause Legionnaires' disease, but is less virulent compared to L. pneumophila strains and very rarely associated with human disease. L.

Regulation, integrase-dependent excision, and horizontal transfer of genomic islands in Legionella pneumophila.

Legionella pneumophila is a Gram-negative freshwater agent which multiplies in specialized nutrient-rich vacuoles of amoebae. When replicating in human alveolar macrophages, Legionella can cause Legionnaires' disease. Recently, we identified a new type of conjugation/type IVA secretion system (T4ASS) in L.

First indication for a functional CRISPR/Cas system in Francisella tularensis.

Francisella tularensis is a zoonotic agent and the subspecies novicida is proposed to be a water-associated bacterium. The intracellular pathogen F. tularensis causes tularemia in humans and is known for its potential to be used as a biological threat.

FliA expression analysis and influence of the regulatory proteins RpoN, FleQ and FliA on virulence and in vivo fitness in Legionella pneumophila.

In Legionella pneumophila, the regulation of the flagellum and the expression of virulence traits are linked. FleQ, RpoN and FliA are the major regulators of the flagellar regulon. We demonstrated here that all three regulatory proteins mentioned (FleQ, RpoN and FliA) are necessary for full in vivo fitness of L.

Phospholipase PlaB is a new virulence factor of Legionella pneumophila.

We previously identified Legionella pneumophila PlaB as the major cell-associated phospholipase A/lysophospholipase A with contact-dependent hemolytic activity. In this study, we further characterized this protein and found it to be involved in the virulence of L. pneumophila.

Phospholipase PlaB of Legionella pneumophila represents a novel lipase family: protein residues essential for lipolytic activity, substrate specificity, and hemolysis.

Legionella pneumophila possesses several phospholipases capable of host cell manipulation and lung damage. Recently, we discovered that the major cell-associated hemolytic phospholipase A (PlaB) shares no homology to described phospholipases and is dispensable for intracellular replication in vitro. Nevertheless, here we show that PlaB is the major lipolytic activity in L.

Identification and characterization of a new conjugation/type IVA secretion system (trb/tra) of Legionella pneumophila Corby localized on two mobile genomic islands.

Horizontal gene transfer probably contributes to evolution of Legionella pneumophila and its adaptation to different environments. Although horizontal gene transfer was observed in Legionella, the mechanism is still not specified. In this study we identified and analysed a new type of conjugation/type IVA secretion system (trb/tra) of L.