The Type II Secretion System Is Essential for Erythrocyte Lysis and Gut Colonization by the Leech Digestive Tract Symbiont Aeromonas veronii
Open Access
- 15 January 2011
- journal article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 77 (2), 597-603
- https://doi.org/10.1128/aem.01621-10
Abstract
Hemolysin and the type II secretion system (T2SS) have been shown to be important for virulence in many pathogens, but very few studies have shown their importance in beneficial microbes. Here, we investigated the importance of the type II secretion pathway in the beneficial digestive-tract association of Aeromonas veronii and the medicinal leech Hirudo verbana and revealed a critical role for the hemolysis of erythrocytes. A mutant with a miniTn5 insertion in exeM, which is involved in forming the inner membrane platform in the T2SS, was isolated by screening mutants for loss of hemolysis on blood agar plates. A hemolysis assay was used to quantify the mutant's deficiency in lysing sheep erythrocytes and revealed a 99.9% decrease compared to the parent strain. The importance of the T2SS in the colonization of the symbiotic host was assessed. Colonization assays revealed that the T2SS is critical for initial colonization of the leech gut. The defect was tied to the loss of hemolysin production by performing a colonization assay with blood containing lysed erythrocytes. This restored the colonization defect in the mutant. Complementation of the mutant using the promoter region and exeMN revealed that the T2SS is responsible for secreting hemolysin into the extracellular space and that both the T2SS and hemolysin export by the T2SS are critical for initial establishment of A. veronii in the leech gut.This publication has 64 references indexed in Scilit:
- The Type 2 Secretion Pseudopilin, gspJ , Is Required for Multihost Pathogenicity of Burkholderia cenocepacia AU1054Infection and Immunity, 2010
- The GenusAeromonas: Taxonomy, Pathogenicity, and InfectionClinical Microbiology Reviews, 2010
- A core gut microbiome in obese and lean twinsNature, 2008
- Interaction between innate immune cells and a bacterial type III secretion system in mutualistic and pathogenic associationsProceedings of the National Academy of Sciences of the United States of America, 2007
- Spatial and Temporal Population Dynamics of a Naturally Occurring Two-Species Microbial Community inside the Digestive Tract of the Medicinal LeechApplied and Environmental Microbiology, 2007
- Human gut microbes associated with obesityNature, 2006
- Genome Sequence of Aeromonas hydrophila ATCC 7966 T : Jack of All TradesJournal of Bacteriology, 2006
- Culture-Independent Characterization of the Digestive-Tract Microbiota of the Medicinal Leech Reveals a Tripartite SymbiosisApplied and Environmental Microbiology, 2006
- Genetic analysis of pigment biosynthesis in Xanthobacter autotrophicus Py2 using a new, highly efficient transposon mutagenesis system that is functional in a wide variety of bacteriaArchiv für Mikrobiologie, 2002
- Gapped BLAST and PSI-BLAST: a new generation of protein database search programsNucleic Acids Research, 1997