Oocyst or sporocyst? Another enigma in the development of cryptosporidia
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| Year of publication | 2013 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Developmental stages of the gastric parasite, Cryptosporidium muris (strain TS03), were obtained from stomachs and faeces of experimentally inoculated Mastomys coucha. The development of C. muris oocysts was mapped in detail using a combined microscopic approach, supported by freeze etching. Two types of wall forming bodies (WFB) of different electron density occurred in mature macrogamonts and zygotes. The WFB, located beneath the zygote pellicle, disintegrated into small particles and migrated in the space between pellicular membranes. Additional membranes seemed to develop beneath the pellicle so that four or more membranes could be seen enveloping more advanced zygote stages. Developing oocysts were enveloped by a parasitophorous sac and their wall comprised of three layers. The outermost one, considered to be a true oocyst, was very fragile and this could be the reason that it usually remains unnoticed. In endogenous stages, this layer was usually separated from inner two layers and often almost unnoticeable as it was adjacent to the inner membrane of parasitophorous sac. The middle thin and the innermost thick layers, on which the characteristic suture could be seen, form the wall of a sporocyst. Fully sporulated sporocysts, found either in stomach or faeces, were released from parasitophorous sac and frequently lacked the outermost layer (oocyst). Under scanning electron microscope, they exhibited either smooth or wrinkly surface, presumably depending on the wall thickness. Furthermore, due to a high variability in wall thickness, authors call into question the existence of two independent types of oocysts (thin- and thick-walled) in cryptosporidia. Financial support provided by projects No. P506/10/P372 and MUNI/A/0937/2012. |
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