Exposure of gnotobiotic Artemia franciscana larvae to abiotic stress promotes heat shock protein 70 synthesis and enhances resistance to pathogenic Vibrio campbellii

Abstract

Larvae of the brine shrimp Artemia franciscana serve as important feed in fish and shellfish larviculture; however, they are subject to bacterial diseases that devastate entire populations and consequently hinder their use in aquaculture. Exposure to abiotic stress was shown previously to shield Artemia larvae against infection by pathogenic Vibrio, with the results suggesting a mechanistic role for heat shock protein 70. In the current report, combined hypothermic/hyperthermic shock followed by recovery at ambient temperature induced Hsp70 synthesis in Artemia larvae. Thermotolerance was also increased as was protection against infection by Vibrio campbellii, the latter indicated by reduced mortality and lower bacterial load in challenge tests. Resistance to Vibrio improved in the face of declining body mass as demonstrated by measurement of ash-free dry weight. Hypothermic stress only and acute osmotic insult did not promote Hsp70 expression and thermotolerance in Artemia larvae nor was resistance to Vibrio challenge augmented. The data support a causal link between Hsp70 accumulation induced by abiotic stress and enhanced resistance to infection by V. campbellii, perhaps via stimulation of the Artemia immune system. This possibility is now under investigation, and the work may reveal fundamental properties of crustacean immunity. Additionally, the findings are important in aquaculture where development of procedures to prevent bacterial infection of feed stock such as Artemia larvae is a priority.

Heat-shock protein 70 expression in the seminal plasma of patients with chronic bacterial prostatitis and chronic prostatitis/chronic pelvic pain syndrome

“…HSP70 has the ability to protect cells from the deleterious effects of inflammation; for example, by refolding and stabilizing denatured protein aggregates. 31 In this study, we found that inflammatory cytokines (TNF-a and IL-1b) and HSP70 synthesis were significantly increased in chronic bacterial prostatitis. This finding is similar to earlier studies of other inflammation diseases, which showed that levels of the inflammatory cytokine IL-1b and HSP70 are both increased in rats infected with E. coli.…”

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

“…Feeding with bacteria, apart from virulent strains such as V. campbellii (Soltanian et al 2007;Sung et al 2008), V. proteolyticus (Marques et al 2006a;Sung et al 2007), and V. harveyi (Soto-Rodriguez et al 2003;Defoirdt et al 2006), enhances Artemia resistance against disease and infection. As one example, colonization of cultures with nine different live bacterial strains protected Artemia juveniles against V. proteolyticus CW8T2 (Verschuere et al 1999).…”

“…Vibrio challenge of Artemia larvae Axenic Artemia larvae were obtained by cyst decapsulation (Sorgeloos et al 1986) followed by incubation at 28°C for 24 h in sea water (Sung et al 2008). Larvae developing within the next 4-6 h, and thus with the ability to ingest bacteria, were harvested and incubated for 6 h with either heat-shocked or nonstressed bacteria at approximately 1× 10 7 cells per milliliter.…”

“…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.…”