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Full-Text Articles in Veterinary Medicine
Edwardsiella Ictaluri Is Capable Of Persisting In Channel Catfish By Evading Host T Cell And Cell Death Responses, Elizabeth Watts Griggs
Edwardsiella Ictaluri Is Capable Of Persisting In Channel Catfish By Evading Host T Cell And Cell Death Responses, Elizabeth Watts Griggs
LSU Doctoral Dissertations
Edwardsiella ictaluri is a gram-negative bacterium of the family Enterobacteriaceae that infects and causes enteric septicemia (ESC) of channel catfish (Ictalurus punctatus), a fatal disease costing the catfish industry millions of dollars in losses each year. Edwardsiella. ictaluri is capable of replicating in catfish head-kidney-derived-macrophages (HKDM), and like many other gram-negative bacteria, E. ictaluri encodes a Type III Secretion System (T3SS) that is required for virulence and intracellular replication. In the case of E. ictaluri, the T3SS translocates effectors from the Edwardsiella containing vacuole (ECV) through the bacterial cell wall and the vacuolar membrane directly to the …
Arginine Metabolism In The Edwardsiella Ictaluri- Channel Catfish Macrophage Dynamic, Wes Arend Baumgartner
Arginine Metabolism In The Edwardsiella Ictaluri- Channel Catfish Macrophage Dynamic, Wes Arend Baumgartner
LSU Doctoral Dissertations
Edwardsiella ictaluri encodes a urease operon and an arginine decarboxylase (AdiA) that are required for virulence in head kidney derived macrophages (HKDM). The urease produces ammonia in amounts sufficient to alter environmental pH from acid to neutral. A hypothetical model was proposed, involving arginine metabolism in E. ictaluri infected HKDM, focusing on bacterial urease, AdiA, a second arginine decarboxylase (SpeA), and agmatinase (SpeB). Using fluorescence based ratiometric pH determination of E. ictaluri in live HKDM, it was shown that E. ictaluri modulates HKDM phagosome pH to above six. Urease and AdiA mutants failed to up-regulate vacuole pH, while vacuole pH …
Characterization Of A Virulence Related Hypothetical Protein In Edwardsiella Ictaluri, Ildiko Katalin Polyak
Characterization Of A Virulence Related Hypothetical Protein In Edwardsiella Ictaluri, Ildiko Katalin Polyak
LSU Master's Theses
Although the biochemical characterization of E. ictaluri, the subsequent disease progression of enteric septicemia of catfish (ESC), and the associated pathologic lesions are well characterized, the mechanism of invasion of E. ictaluri into a susceptible host is poorly understood. Identification and confirmation of virulence factors and associated genes of E. ictaluri is crucial to elucidating the pathogenesis of this important disease. A signature tagged mutagenesis (STM) study conducted by Thune et al. (2006) identified 50 E. ictaluri clones with transposon insertions in genes potentially involved in pathogenesis. A specific STM mutant, 233PR, carrying a transposon insertion in a gene encoding …
The Role Of Urease In The Pathogenesis Of Edwardsiella Ictaluri, Natha Joy Booth
The Role Of Urease In The Pathogenesis Of Edwardsiella Ictaluri, Natha Joy Booth
LSU Doctoral Dissertations
An Edwardsiella ictaluri strain with disruption of ureG was identified through the use of signature tagged insertion mutagenesis as being attenuated for virulence in the channel catfish host. Sequencing of the flanking regions surrounding the insert showed that the gene was part of a urease gene complex that included ureE, ureF, ureG, ureD, ureI, and an ammonium transporter homologue. The ureG gene encodes a GTP-binding accessory protein which is thought to function in energy-dependent urease assembly. The ureG mutant strain was found to be attenuated for mortality, persistence, and for the ability to establish infection in a competition challenge during …