title: Effects of frozen storage on the structure of sarcocysts in pig muscle and implications in taxonomic studies.
abstract: The morphology of the cyst wall of Sarcocystis has unique characteristics that can be used in species identification. To find a suitable way to preserve Sarcocystis cyst samples for species identification, by light microscopy and electron microscopy, we recorded the morphological changes in the cysts of Sarcocystis suihominis and Sarcocystis miescheriana from pig muscle, induced by storage at -20 degrees C. Comparisons were made between fresh cysts and those subjected to frozen storage for periods of 3 days, 20 days and 30 days.
  
  
  RESULTS
  cyst wall of the two Sarcocystis species appeared unaffected by storage. There was no obvious change in the length, nor in the width of the protrusions after storage (P>0.05), but the structure of the bradyzoite in the sarcocyst was in many cases disintegrated at -20 degrees C in 20 days for S. miescheriana and 30 days for S. suihominis. To our knowledge this is the first report that Sarcocystis cyst in muscle can be stored at -20 degrees C before and remain suitable for ultrastructural morphological study. Consequently, this paper proposes freezing as a convenient storage method for samples used in taxonomic studies of Sarcocystis.
authors.affiliation: Parasitology Department, Kunming Medical College, Kunming, Yunnan, China.
authors.forename: Lian-Yong
authors.initials: LY
authors.lastname: Chen
authors.forename: Ben-Jiang
authors.initials: BJ
authors.lastname: Zhou
authors.forename: Zhao-Qing
authors.initials: ZQ
authors.lastname: Yang
authors.forename: Cui-Ying
authors.initials: CY
authors.lastname: Li
authors.forename: S W
authors.initials: SW
authors.lastname: Attwood
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Lei
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Sun
authors.forename: Zai-Xing
authors.initials: ZX
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000592:standards*; D046529:Microscopy, Electron, Transmission; D018482:Muscle, Skeletal / Q000469:parasitology*; D012522:Sarcocystis / Q000145:classification / Q000648:ultrastructure*; D013552:Swine; D013997:Time Factors