DSpace university logo mark
Advanced Search
Japanese | English 

NAOSITE : Nagasaki University's Academic Output SITE > Faculty of Fisheries > Articles in academic journal >

Comparison of the responses of peritoneal macrophages from Japanese flounder (Paralichthys olivaceus) against high virulent and low virulent strains of Edwardsiella tarda.


File Description SizeFormat
FSI24_243.pdf193.52 kBAdobe PDFView/Open

Title: Comparison of the responses of peritoneal macrophages from Japanese flounder (Paralichthys olivaceus) against high virulent and low virulent strains of Edwardsiella tarda.
Authors: Ishibe, Keiko / Osatomi, Kiyoshi / Hara, Kenji / Kanai, Kinya / Yamaguchi, Kenichi / Oda, Tatsuya
Issue Date: Feb-2008
Publisher: Elsevier Ltd
Citation: Fish & shellfish immunology, 24(2), pp.243-251; 2008
Abstract: In vivo infection studies in Japanese flounder (Paralichthys olivaceus) demonstrated that the number of viable cells of the virulent strain (NUF251) of Edwardsiella tarda increased gradually in kidney and hepato-pancreas after intraperitoneal injection, but the low virulent strain (NUF194) did not. To gain insight into the virulence factors of E. tarda, in vitro responses of Japanese flounder (P. olivaceus) peritoneal macrophages to these strains were compared in terms of phagocytosis, bactericidal activity, and reactive oxygen species (ROS) generation as measured by chemiluminescence (CL) responses. Microscopic observation revealed that these two strains of E. tarda were phagocytosed by the peritoneal macrophages, and there was no significant difference in the mean numbers of ingested bacteria per macrophage between these strains. A gradual increase in the number of viable cells of the highly virulent strain within macrophages was observed during 9h post-phagocytosis, whereas no significant replication of the low virulent strain within macrophages was detected. These results suggest that the virulent strain of E. tarda has an ability to survive and replicate within macrophages, while the low virulent strain has no such ability. When the peritoneal macrophages were exposed to the opsonized low virulent E. tarda strain, a rapid increase in CL response was induced. However, the highly virulent strain caused only background level of CL response. By the subsequent stimulation with phorbol myristate acetate, the macrophages exposed to the virulent E. tarda strain showed extremely higher CL response than that of the one exposed to the low virulent E. tarda strain. These results suggest that the virulent E. tarda prevents the activation of ROS generation system during phagocytosis, though the system is still capable of responding to other stimulation. The virulent strain significantly reduced the CL response induced by xanthine/xanthine oxidase system, while the low virulent strain had almost no effect. Furthermore, the virulent strain showed greater resistance to H(2)O(2) than the low virulent strain. Our results suggest that the virulent strain of E. tarda is highly resistant to ROS, and such ability might allow the organism to survive and multiply within phagocytes, and may serve to disseminate E. tarda throughout the host during in vivo infection.
Keywords: Bacterial infection / Chemiluminescence / Edwardsiella tarda / Fish peritoneal macrophages / Japanese flounder / Oxidative burst / Phagocyte
URI: http://hdl.handle.net/10069/22349
ISSN: 10504648
DOI: 10.1016/j.fsi.2007.11.001
PubMed ID: 18178102
Rights: Copyright © 2007 Elsevier Ltd All rights reserved.
Type: Journal Article
Text Version: author
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/22349

All items in NAOSITE are protected by copyright, with all rights reserved.

 

Valid XHTML 1.0! Copyright © 2006-2015 Nagasaki University Library - Feedback Powerd by DSpace