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Heat shock proteins as protective agents against the enteric redmouth syndrome caused by Yersinia ruckeri

Jana Ryckaert (UGent)
(2010)
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Abstract
The increasing demand for aquaculture products has been accompanied by a similar increase in the search for environmentally friendly alternatives for antibiotics. Prevention of diseases and protection against stress will play key roles in the successful growth of aquaculture. The present work has explored the application of heat shock proteins (HSPs) as an approach to disease control in aquaculture. In a first experimental study, an infection model was developed with platyfish as a host for Yersinia ruckeri infections. Using this model, it was demonstrated that an increase in endogenous HSPs after non-lethal heat shock (NLHS) did not protect the fish against Y. ruckeri induced mortality. However, injecting the fish with bacterial HSPs at a concentration of 1 µg per fish had a beneficial effect, and this effect on survival was significant when the treatment with bacterial HSPs was combined with a NLHS. Spurred by these interesting results, it was decided to examine the effects on the innate immune response of fish more exhaustively. Before this could be done, more information was needed on the non-specific defence of fish against Y. ruckeri. A second experimental study was set up to unravel the interactions between Y. ruckeri and rainbow trout head kidney macrophages. Results showed the capacity of Y. ruckeri to survive in trout macrophages in vitro as well as in vivo, confirming its facultative intracellular nature. Subsequently, the effects of E. coli HSPs on interactions between Y. ruckeri and primary macrophages from the head kidney of rainbow trout were investigated in a third experimental study. In vitro and in vivo, purified DnaK had no effect on subsequent uptake and intracellular survival of Y. ruckeri in primary macrophages. Nevertheless, overproduction of certain prokaryotic HSPs by transformed E. coli did affect the macrophage response to these bacteria. Bacteria that only overproduce DnaK evoked a higher respiratory burst and a higher number of intracellular bacteria in primary head kidney macrophages, while E. coli treated to overproduce a combination of bacterial HSPs, elicited a lower production of reactive oxygen species and ingestion. These results suggest that HSPs interfere with early interactions between piscine macrophages and bacterial pathogens, depending on the way they are delivered to the cells. In conclusion, the results denoted in this thesis indicate a possible role for HSPs as a new immunostimulating treatment in aquaculture. In the future, fundamental research has to be performed to elucidate the complex interactions between HSPs and the immune response.
Keywords
enteric redmouth syndrome, Yersinia ruckeri, Heat shock proteins

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Citation

Please use this url to cite or link to this publication:

Chicago
Ryckaert, Jana. 2010. “Heat Shock Proteins as Protective Agents Against the Enteric Redmouth Syndrome Caused by Yersinia Ruckeri”. Ghent, Belgium: Ghent University. Faculty of Bioscience Engineering.
APA
Ryckaert, J. (2010). Heat shock proteins as protective agents against the enteric redmouth syndrome caused by Yersinia ruckeri. Ghent University. Faculty of Bioscience Engineering, Ghent, Belgium.
Vancouver
1.
Ryckaert J. Heat shock proteins as protective agents against the enteric redmouth syndrome caused by Yersinia ruckeri. [Ghent, Belgium]: Ghent University. Faculty of Bioscience Engineering; 2010.
MLA
Ryckaert, Jana. “Heat Shock Proteins as Protective Agents Against the Enteric Redmouth Syndrome Caused by Yersinia Ruckeri.” 2010 : n. pag. Print.
@phdthesis{2057594,
  abstract     = {The increasing demand for aquaculture products has been accompanied by a similar increase in the search for environmentally friendly alternatives for antibiotics. Prevention of diseases and protection against stress will play key roles in the successful growth of aquaculture. The present work has explored the application of heat shock proteins (HSPs) as an approach to disease control in aquaculture.
In a first experimental study, an infection model was developed with platyfish as a host for Yersinia ruckeri infections. Using this model, it was demonstrated that an increase in endogenous HSPs after non-lethal heat shock (NLHS) did not protect the fish against Y. ruckeri induced mortality. However, injecting the fish with bacterial HSPs at a concentration of 1 µg per fish had a beneficial effect, and this effect on survival was significant when the treatment with bacterial HSPs was combined with a NLHS.
Spurred by these interesting results, it was decided to examine the effects on the innate immune response of fish more exhaustively. Before this could be done, more information was needed on the non-specific defence of fish against Y. ruckeri. A second experimental study was set up to unravel the interactions between Y. ruckeri and rainbow trout head kidney macrophages. Results showed the capacity of Y. ruckeri to survive in trout macrophages in vitro as well as in vivo, confirming its facultative intracellular nature. 
Subsequently, the effects of E. coli HSPs on interactions between Y. ruckeri and primary macrophages from the head kidney of rainbow trout were investigated in a third experimental study. In vitro and in vivo, purified DnaK had no effect on subsequent uptake and intracellular survival of Y. ruckeri in primary macrophages. Nevertheless, overproduction of certain prokaryotic HSPs by transformed E. coli did affect the macrophage response to these bacteria. Bacteria that only overproduce DnaK evoked a higher respiratory burst and a higher number of intracellular bacteria in primary head kidney macrophages, while E. coli treated to overproduce a combination of bacterial HSPs, elicited a lower production of reactive oxygen species and ingestion. These results suggest that HSPs interfere with early interactions between piscine macrophages and bacterial pathogens, depending on the way they are delivered to the cells.
In conclusion, the results denoted in this thesis indicate a possible role for HSPs as a new immunostimulating treatment in aquaculture. In the future, fundamental research has to be performed to elucidate the complex interactions between HSPs and the immune response.},
  author       = {Ryckaert, Jana},
  isbn         = {9789059893689},
  keywords     = {enteric redmouth syndrome,Yersinia ruckeri,Heat shock proteins},
  language     = {eng},
  pages        = {V, 176},
  publisher    = {Ghent University. Faculty of Bioscience Engineering},
  school       = {Ghent University},
  title        = {Heat shock proteins as protective agents against the enteric redmouth syndrome caused by Yersinia ruckeri},
  year         = {2010},
}