Feeding Artemia franciscana (Kellogg) larvae with bacterial heat shock protein, protects from Vibrio campbellii infection

Abstract

Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli. A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture.

Ingestion of bacteria overproducing DnaK attenuates Vibrio infection of Artemia franciscana larvae

“…Additionally, immunoprobing of Western blots and protein quantification by ELISA demonstrated that enhanced protection is associated with increased DnaK accumulation in bacteria used as feed. Previously, feeding with E. coli overexpressing DnaK, produced under the control of either its own promoter or a heterologous arabinose-inducible promoter, boosted Artemia survival approximately threefold (Sung et al 2009). The present study extends these observations, demonstrating clearly that DnaK-producing bacteria other than E. coli confer protection upon Artemia larvae.…”

“…Protein extraction was as described (Sung et al 2009). Bacteria were homogenized in the presence of 0.1 mm diameter glass beads in ice-cold buffer K (150 mM sorbitol, 70 mM potassium gluconate, 5 mM MgCl 2 , 5 mM NaH 2 PO 4 , 40 mM HEPES, pH 7.4) (Clegg et al 2000a) containing protease inhibitors (catalog no.…”

“…As an unexpected finding, extracellular Hsp70, in combination with other Hsps, is thought to modulate peptide positioning on cell surfaces, thus enhancing immune recognition of aberrant cells (Athman and Philpott 2004;Johnson and Fleshner 2006). Of interest in this regard is research on economically important organisms used in aquaculture such as Penaeus monodon (de la Vega et al 2006) and Artemia franciscana (Sung et al 2007(Sung et al , 2008(Sung et al , 2009, where Hsp70 is implicated in protection against pathogenic microbes, perhaps by stimulation of the immune response.…”

“…However, this advance necessitates rearing Artemia larvae under conditions where infection by bacteria and other pathogens must be controlled. In relation to this requirement, endogenous Hsp70 (Sung et al 2007(Sung et al , 2008 and exogenously supplied DnaK synthesized in transformed Escherichia coli (Sung et al 2009) were shown to protect Artemia larvae from Vibrio infection, perhaps by immune stimulation. The objective of the present study was, therefore, to substantiate the observations that bacteria overproducing DnaK protect Artemia larvae from Vibrio infection.…”

ArHsp40, a type 1 J-domain protein, is developmentally regulated and stress inducible in post-diapause Artemia franciscana

“…Hsp70 has a role in the growth of A. franciscana (Clegg et al 2000;Willsie and Clegg 2002) and protection against stress, including heat and pathogenic bacteria (Sung et al 2008(Sung et al , 2009aBaruah et al 2011), but information on its major co-chaperone, Hsp40, is lacking as it is for most crustaceans. With this in mind, a search was initiated for J-domain proteins in A. franciscana resulting in the cloning and sequencing of a complementary DNA (cDNA), termed ArHsp40, encoding a type I Hsp40.…”