The kinetoplastid parasite Azumiobodo hoyamushi, the causative agent of soft tunic syndrome of the sea squirt Halocynthia roretzi, resides in the East Sea of Korea

Quantitative assessment of Azumiobodo hoyamushi distribution in the tunic of soft tunic syndrome¿affected ascidian Halocynthia roretzi using real-time polymerase chain reaction

“…To construct a standard curve for the quantification procedures, A. hoyamushi was cultured in vitro according to our previous study [5]. DNA was extracted from 1,00,000 cells cultivated in vitro using a DNA extraction kit (Qiagen, USA), and the DNA was eluted in 200 μL of Buffer AE (Qiagen, USA).…”

“…The primer pair and the probe were designed based on specific regions in the 18S rRNA of A. hoyamushi isolated from the ascidians of Tongeong, Korea (GenBank accession number, KF479402), and DNA extracted from the tunic of an STSfree ascidian and kinetoplastid protozoans (Procryptobia sorokini) were used as the negative controls. The STS-free ascidian was obtained by the formalin bath method [14], and P. sorokini was isolated from STS-affected ascidians and propagated in vitro in minimum essential medium [5]. The cycling program consisted of an initial denaturation step at 94°C for 5 min, followed by 45 cycles each of 94°C for 15 s, 47°C for 1 min and 72°C for 30 s in a qPCR machine (Exicycler™, Bioneer, Korea).…”

“…Recently, our group also isolated a kinetoplastid protozoan from STS-affected ascidians cultured in the East Sea of Korea and found that the 18S rRNA sequence of the organism was highly homologous to that of the A. hoyamushi isolated in Japan, suggesting a common causative pathogen for STS in both Korea and Japan [5].…”

Methods to eradicate soft tunic syndrome (STS)-causing protozoa Azumiobodo hoyamushi, the highly infectious parasite from the edible ascidian (Halocynthia roretzi)

“…Starting from the late 1980's, soft tunic syndrome (STS) has become one of the most notorious nuisances in Korean ascidian culture industry (Kim et al 2014). The disease is now known to be caused by a protozoan pathogen Azumiobodo hoyamushi (A. hoyamushi).…”

“…The disease is now known to be caused by a protozoan pathogen Azumiobodo hoyamushi (A. hoyamushi). This parasite resides within the tunic tissue leading to disintegration of the cellulose-based exoskeleton structure of the ascidian (Kumagai et al 2010(Kumagai et al , 2011Kim et al 2014). It has been reported that the parasite is opportunistic in plaguing the cultured ascidian, but the pathogen has also been reported to be present in other similar marine animals.…”