Redescription of Sarcocystis fusiformis sarcocysts from the water buffalo (Bubalus bubalis)

Abstract

S U M M A R YFour valid species of Sarcocystis have been reported from the water buffalo (Bubalus bubalis): Sarcocystis fusiformis, Sarcocystis buffalonis, Sarcocystis levinei and Sarcocystis dubeyi. Here, we redescribe structure of S. fusiformis sarcocysts by scanning and transmission electron microscopy (SEM, TEM). Twenty-one macroscopic sarcocysts from oesophagus of the water buffalo in Egypt were examined by light microscopy, SEM and TEM. The sarcocyst wall was up to 9 μm thick, depending on the section and the technique. In 5 μm paraffin-embedded sections, the sarcocyst wall was indistinct, 2-5 μm thick and appeared smooth. In 1 μm plastic-embedded sections stained with toluidine blue, the sarcocyst wall was 2·5-5·2 μm thick and had branched villar protrusions (vp)-like branches of a dead tree. By SEM, the sarcocyst wall had a mesh-like structure with irregularly shaped vp that were folded over the sarcocyst wall. On each vp there were uniform papillomatous structures that were 100 nm wide. By TEM, vp were up to 6 μm long and contained filamentous tubular structures, most of which were parallel to the long axis of the projections; granules were absent from these tubules. By TEM, bradyzoites within the same cyst varied from 11·2 to 16·8 μm in length. By TEM, bradyzoites had a very long (10 μm) convoluted mitochondrion, up to 12 dense granules, but only 2 rhoptries. This redescription should help to differentiate the sarcocysts of S. fusiformis from similar sarcocysts in domestic and wild ruminants.

Molecular characterisation of three regions of the nuclear ribosomal DNA unit and the mitochondrial cox1 gene of Sarcocystis fusiformis from water buffaloes (Bubalus bubalis) in Egypt

“…Thus, the fine structure of the sarcocysts has been reported in several papers (Ghaffar et al 1978; Kan and Dissanaike 1978;Tongson and Molina 1979;Zaman et al 1980;Parairo et al 1988;Dubey et al 1989b;Jehle et al 2009;Abu-Elwafa et al 2015;Dubey et al 2015), and S. fusiformis was among the first Sarcocystis spp. to have its complete life cycle elucidated, when it was shown that domestic cats acted as definitive hosts (Dissanaike et al 1977a, b;Scholtyseck and Hilali 1978).…”

“…Hence, they seemed to have been amplified from DNA belonging to S. fusiformis, which presumably also predominated in the templates. The aberrant sequences could possibly have represented non-functional copies of the genes originating from slightly degenerate DNA in dead or dying merozoites in the central portion of the large sarcocysts, which is known to contain few intact merozoites (Manuel et al 1983;Dubey et al 2015). If so, they may constitute a very small fraction of the total number of copies of the genes present in the DNA templates and may therefore not be detected by direct sequencing of PCR products.…”

“…At the first sampling, in March 2014, six fairly large and thick sarcocysts (7-11 mm long and 4-5 mm wide) were collected from each of four water buffaloes (Bb1-Bb4). Each of these sarcocysts were cut transversely into two halves, of which one half was used for the present molecular study, and the other half was used for a separate morphological study (Dubey et al 2015). In November 2014, nine smaller and more slender sarcocysts (3-4 mm long and 1-2 mm wide) were collected from eight more water buffaloes (Bb5, Bb6, Bb8-Bb11, Bb13, Bb15).…”

Sarcocystis oreamni, n. sp. (Apicomplexa: Sarcocystidae) from the mountain goat (Oreamnos americanus)

“…Formalin-fixed tissues were embedded in paraffin, sectioned 5 µm thick and stained with hematoxylin and eosin (H and E). After examination of the H and E sections, cysts canditates for electron microscopy were excised with the help of an scalpel and processed as described by Dubey et al (2015b). rRNA (~925 bp), and ITS-1 (~900 bp) were excised and purified using QIAquick Gel Extraction (Qiagen, Inc., Valencia, CA).…”

Sarcocystis mehlhorni, n. sp. (Apicomplexa: Sarcocystidae) from the black-tailed deer (Odocoileus hemionus columbianus)

“…Fresh muscles were examined for sarcocysts presence by squeezing; individual cysts were excised and kept frozen until molecular assays. Five cysts detected in the HE sections of deer #14183 were excised and processed for transmission electron microscopy (TEM) as reported by Dubey et al (2015b).…”