Chemoresponse of actinosporean spores of Myxobolus cultus to skin mucus of goldfish Carassius auratus

Abstract

Chemoresponse of actinosporean spores of Myxobolus cultus to goldfish mucus was studied and determination of the reactants was attempted. Reactiv~ty was counted as the percentage of empty actinosporean spores after mixing with the mucus The activity of mucus was lnaintained at -80°C but was n~ostly lost within 1 d at 5°C Heating at 30 to 80°C for 30 min did not affect the activity While neutral pH favored the reaction, strong a c~d and alkali decreased the reaction Phosphate buffer saline and sodlum chlonde solutions w t h inolanty >O 05 M inhibited the reaction A shnnkage of sporoplasms Inside the eplspore cavity caused by the high osmotic pressure was obseived Punficatlon of the reactants from goldfish mucus by gel filtration and ultrafiltrat~on revealed that they were lo~v-molecular-weight substances (c6000 h4W) Additionally, fish mucus from other flsh species (such as common carp Cyprinus carpio loach ~Misguinus angulll~cal~datus, r a~n b o w t~o u t Oncorhynchus mykiss, catfish Parasilurus asotus, and Japanese eel Anguilla japonica), as lvell as mucin from bovine submaxillary gland were slm~larly actlve It is suggested that actlnosporean spores I ecognlze fish hosts ~l t h low-molecular-xveight mucin components in skln mucus and that the portal of entry 1s the outer surface of flsh KEY WORDS: Myxosporean .

In vivo exposure of susceptible and non-susceptible fish species to Myxobolus cerebralis actinospores reveals non-specific invasion behaviour

“…Several other species of actinospores showed polar filament discharge or sporoplasm emission when they were offered mucus samples of non-susceptible hosts (Yokoyama et al 1993, 1995, McGeorge et al 1997, Özer & Wootten 2002, Yokoyama & Urawa 1997, Kallert & El-Matbouli 2008. However, reports on pronounced host specificity during reactions to host stimuli among actinospores are scarce.…”

Transmission Biology of the Myxozoa

“…Thus, it is not clearly understood whether the chemical stimulation with fish mucus reflects the host specificity of myxosporeans. Actinospores of M. cultus reacted not only to the skin mucus from natural host but also to the mucus from abnormal host and even to mucin from bovine submaxillary gland (Yokoyama et al, 1995). Further, purification of the reactants from fish mucus by gel filtration and ultrafiltration revealed that they were low-molecular-weight (<6000 MW) substances (Yokoyama et al, 1995).…”

“…Actinospores of M. cultus reacted not only to the skin mucus from natural host but also to the mucus from abnormal host and even to mucin from bovine submaxillary gland (Yokoyama et al, 1995). Further, purification of the reactants from fish mucus by gel filtration and ultrafiltration revealed that they were low-molecular-weight (<6000 MW) substances (Yokoyama et al, 1995). Yokoyama et al (2006) indicated that M. arcticus actinospores reacted to the mucus of the susceptible host, masu salmon (Oncorhynchus masou) as well as non-susceptible hosts, sockeye salmon (O. nerka) and goldfish (Carassius auratus), whereas T. hovorkai actinospores reacted only to the susceptible host, common carp (Cyprinus carpio).…”

A Review: Gaps in Our Knowledge on Myxozoan Parasites of Fishes

“…Skin mucus of the host fish has been shown to induce the polar filament extrusion of actinospores followed by the release of sporoplasms, suggesting that actinospores find the host by certain chemical substances in fish mucus (Yokoyama et al, 1993;Uspenskaya, 1995;Xiao and Desser, 2000b;Ozer and Wootten, 2002). Yokoyama et al (1995) demonstrated that low-molecular mucin components stimulated the polar filament extrusion of raabeia actinospores of Myxobolus cultus. A contradictory result was obtained by El -Matbouli et al (1999a), where triactinomyxon spores of M. cerebralis were not activated by the mucus of rainbow trout, perhaps indicating that both mechanical and chemical stimulations are required for host-finding in M. cerebralis.…”