title: Quantitative assessment of Azumiobodo hoyamushi distribution in the tunic of soft tunic syndrome-affected ascidian Halocynthia roretzi using real-time polymerase chain reaction.
abstract: BACKGROUND
  The kinetoplastid parasite, Azumiobodo hoyamushi, is the causative agent of soft tunic syndrome (STS) in ascidians and leads to their mass mortality in Korean waters. This study was conducted to quantify A. hoyamushi density during the development of STS in the tunics of ascidians (Halocynthia roretzi) using real-time polymerase chain reaction (qPCR).
  
  
  RESULTS
  The infection intensity of A. hoyamushi, as measured by qPCR, varied depending on the part of the tunic analyzed, as well as the stage of STS development. The highest infection intensity was recorded in the tunics of the siphons. The infection intensity of A. hoyamushi in the siphons was only 2.9 cell/tunic (area, 0.25 cm(2)) or 106.0 cell/gram tunic (GT) in the early phase of STS, but this value increased dramatically to 16,066 cells/tunic (0.25 cm(2)) or 617,004 cell/GT at the time of death. The number of A. hoyamushi parasites increased gradually and their distribution spread from the siphons to the other parts of the tunics.
  
  
  CONCLUSIONS
  qPCR enabled the quantitation of A. hoyamushi and the results revealed that parasite density increased as STS progressed. In addition, our results suggested that the siphons might function as the portal of entry for A. hoyamushi during infection.
authors.affiliation: National Fisheries Research and Development Institute, Busan, 619-705, Republic of Korea. yunkshin@korea.kr.
authors.forename: Yun-Kyung
authors.initials: YK
authors.lastname: Shin
authors.affiliation: Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea. woong@kunsan.ac.kr.
authors.forename: Ki-Woong
authors.initials: KW
authors.lastname: Nam
authors.affiliation: Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea. khpark@kunsan.ac.kr.
authors.forename: Kwan Ha
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea. jmyoon@kunsan.ac.kr.
authors.forename: Jong-Man
authors.initials: JM
authors.lastname: Yoon
authors.affiliation: Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea. kipark@kunsan.ac.kr.
authors.forename: Kyung-Il
authors.initials: KI
authors.lastname: Park
mesh_terms: D000818:Animals; D054884:Host-Pathogen Interactions; D016830:Kinetoplastida / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014561:Urochordata / Q000469:parasitology*