Ultrastructural variation of Blastocystis hominis stocks in culture

Extreme anoxia tolerance in embryos of the annual killifishAustrofundulus limnaeus: insights from a metabolomics analysis

“…This is highly unlikely considering that these progeny appear strikingly similar to metabolic granules described previously and are therefore simply variants of the granular form (257,290). Cytoplasmic contents, often containing organelles, may invaginate and deposit filament-or vesicle-like membrane-bound structures into the central vacuole (65,159,160,181,235,239,252). The exact significance of this process is unclear, although it has been postulated to be a mechanism of apoptotic body deposition in Blastocystis cells undergoing programmed cell death (254).…”

“…Two recent reports (163,201) revealed that pigs may harbor subtype 2, which, until those studies, comprised isolates only from humans and primates. Blastocystis cells often possess one or two nuclei, and occasionally, quadrinucleate cells and cells possessing numerous nuclei have been reported (65,142,146,319,321). Whether these multinuclear states impact molecular and phylogenetic analyses is currently not known.…”

“…The organism is often surrounded by a surface coat (Fig. 2B), sometimes referred to as the fibrillar layer or capsule, of various thicknesses (65). The surface coat is often thicker in parasites freshly isolated from feces and gradually thins out during prolonged laboratory culture (40,235), and cells without surface coats have been observed in vitro (65).…”

“…2B), sometimes referred to as the fibrillar layer or capsule, of various thicknesses (65). The surface coat is often thicker in parasites freshly isolated from feces and gradually thins out during prolonged laboratory culture (40,235), and cells without surface coats have been observed in vitro (65). The reason for this thinning out is unknown but may be due to the postulated role of the coat in trapping bacteria for nutritional purposes (311,314), which is not possible during axenic culture, or may be unnecessary if nutrients provided in laboratory culture are sufficient for growth.…”

“…These are more frequently observed in nonaxenized, older, and antibiotic-treated cultures and have been described as being vacuolar forms containing granules rather than as being a distinct parasite stage (33,233). The intracellular granules are heterogeneous and have been described as being myelin-like inclusions, small vesicles, crystalline granules, and lipid droplets (65). Reproductive granules within the central vacuole have been described and have been reported to function in schizogony-like division (220,241,319).…”