Ethanol and isopropanol trigger rapid egress of intracellular Eimeria tenella sporozoites

Abstract

Egress from host cells is a vital step of the intracellular life cycle of apicomplexan parasites such as Toxoplasma gondii. This phenomenon has attracted attentions from many research groups. Previous studies have shown that ethanol could stimulate the release of microneme proteins by elevating intracellular Ca(2+) concentration of T. gondii, resulting in the parasite egress from host cells. However, little information about egress is known on Eimeria species, the causative agent of coccidiosis in poultry and livestock. In this report, we studied the effect of ethanol and isopropanol on the egress of eimerian parasites. Eimeria tenella sporozoites cultured in primary chicken kidney cells were treated with ethanol and isopropanol, then the egressed parasites were analyzed. Ethanol and isopropanol could induce the rapid egress of E. tenella sporozoites from host cells. No substantial damage was found in parasite-egressed host cells. Compared to the freshly isolated sporozoites, the re-invading ability and reproductivity of the egressed parasites significantly decreased by 43.4 and 44.1 % individually. We also found that fewer sporozoites egressed from host cells when the parasites developed for a longer time before the alcohol treatment. These results demonstrate an in vitro egress mode different from that of T. gondii, facilitating the deciphering of the mechanisms of egress of eimerian parasites.

2-Nitro-1-propanol improved nutrient digestibility and oocyst shedding but not growth performance of Eimeria-challenged broilers

“…The amount of sporozoites or schizonts in the Madin-Darby bovine kidney cells was reduced by 1-mM NP in the medium. Similarly, previous studies reported that isopropanol, ethanol, and acetaldehyde caused the egress of sporozoites of E. tenella from the host cells ( Yan et al., 2015 , 2016 ). Furthermore, egressed sporozoites had less reinvading ability and productivity than the fresh sporozoites ( Yan et al., 2015 , 2016 ).…”

“…Similarly, previous studies reported that isopropanol, ethanol, and acetaldehyde caused the egress of sporozoites of E. tenella from the host cells ( Yan et al., 2015 , 2016 ). Furthermore, egressed sporozoites had less reinvading ability and productivity than the fresh sporozoites ( Yan et al., 2015 , 2016 ). The egressed sporozoites triggered by chemicals might be one of the reasons that 200-ppm NP reduced 30% of the oocysts production in the present study.…”

Nitric oxide stimulates early egress of Toxoplasma gondii tachyzoites from human foreskin fibroblast cells

“…Another study showed that the addition of Ca 2+ ionophores induces the rapid egress of Neospora caninum tachyzoites from bovine endothelial cells [ 24 ]. Recent research on Eimeria tenella revealed that ethanol, a reagent that is able to elevate intracellular Ca 2+ levels, induces sporozoite egress from primary chicken kidney cells [ 25 ]. Consistent with the findings on T. gondii, we hypothesised that Ca 2+ is a universal signalling molecule of the egress process in apicomplexan parasites.…”

Life cycle stages, specific organelles and invasion mechanisms ofEimeriaspecies

“…A variety of treatments that cause transient fluxes of cytosolic Ca 2 + induce MIC secretion in T. gondii tachyzoites including calcium ionophores (Carruthers and Sibley, 1999), ethanol and acetaldehyde, but this is dependent upon the presence of albumin and cGMP signalling (Brown et al, 2016). Similarly in E. tenella, acetaldehyde and ethanol stimulate Ca 2+ -dependent MIC secretion and premature egress of sporozoites from cultured cells in the presence of serum (Yan et al, 2015(Yan et al, , 2016, however in the absence of serum or albumin neither ionophores nor ethanol/acetaldehyde are effective (F. M. Tomley and J. M. Bumstead, unpublished). Thus it appears that cGMP and Ca 2+ -signalling pathways work co-operatively in MIC signalling, with PKG I at the plasma membrane being the essential 'master' regulator (Brown et al, 2017) whilst members of the CDPK family provide the selectivity and specificity needed to carry out specific biological functions such as invasion or egress.…”