碩士 / 國立中興大學 / 獸醫學系 / 86 / AbstractThe phagocytes are believed to play the major role in
fish non-specific defense against most aquatic pathogens and
irritants. In this study, the phagocytes of tilapia (Oreochromis
nilotica) and rainbow trout (Oncorhynchus mykiss) isolated from
blood, head kidney and spleen were used to compare the
phagocytosis and eradication abilities against several aquatic
pathogens such as Vibrio parahaemolyticus, V. anguillarum, V.
vulificus, Aeromonas hydrophilia and Streptococcus spp. using
flow cytometry analysis. In general, the blood phagocytes had
better phagocytosis capability than spleen and head kidney
phagocytes in engulfing the same pathogen. The results also
demonstrated that bacteria opsonized with or without fish serum
in advance did not influence most phagocytes to uptake and
eradicate same bacteria after 120 minutes incubation, but
tilapia spleen phagocytes could enhance their activity when
bacteria opsonized with 1:256 fold diluted fish serum. In
addition, the number of bacteria (V. parahaemolyticus) engulfed
by tilapia spleen phagocytes would obviously decrease if
bacteria were heat inactivated before interacting with
phagocytes.Moreover, all phagocytes showed higher capability of
phagocytosis against most toxigenic bacteria especially those
could produce hemolysins and extracellular products (ECPs) to
induce significant cytotoxicity of phagocytes. In order to
characterize the influence of bacterial toxicity, bacteria were
cultured in LB broth containing different concentration of
2,2'-dipyridyl to simulate the pathogens growing at iron-
limiting condition while interacting with phagocytes in fish.
The results showed both A. hydrophilia (A2) and V. anguillarum
(Va2) apparently increased their hemolytic and cytotoxic
efficiency against all phagocytes under iron starvation.
Furthermore, the ECPs could induce granulation and size
variation of phagocytes and affect their eradication ability.
However, ECPs of A. hydrophilia (A2) did obviously enhance
rainbow trout and tilapia head kidney phagocytes for uptaking
other less or non-pathogenic bacteria. In contrast, ECPs of A.
hydrophilia (A1), without any cellular cytotoxicity against
phagocytes, showed no influence the capability of phagocytosis.
| Identifer | oai:union.ndltd.org:TW/086NCHU1541024 |
| Date | January 1998 |
| Creators | Yu, Chun-ming, 余俊明 |
| Contributors | Lin Yung-Chang, 簡茂盛 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 70 |
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