Fig. 8

Schematic diagram depicting the major findings in the current study. One of the critical findings in this study is that the life cycle and the morphology of Blastocystis sp. are host dependent and undergo alteration because of the host microenvironment such as the gut microbiota. (1) Exposure of the SZ gut microbiota causes an alteration of in phenotypic characteristics of Blastocystis sp. such as increased parasite diameter up to 140 µM and longer average generation time of 34.9 ± 15.06 h. SZ isolates consistently showed a medium to high lectin staining indicating rough surface morphology. (2) There was also a significant increase in amoebic forms among SZ isolates, which resulted in higher resistance of metronidazole treatment with predominant cysteine and serine protease activity. The SZ isolates also demonstrated higher average cell proliferation of HCT116 cell line. (3) The resultant granular forms are more robust and produces more viable vacuolar forms of the parasite [100]. (4) The NS isolates exhibited higher growth rate (17.31 ± 5.4) with consistently smaller diameter (34 µM). NS isolates demonstrated variation in surface lectin staining (predominantly high with smaller percentage showing little to no fluorescence) and low amoebic forms. NS isolates also showed lower resistance towards metronidazole treatment with predominant metalloprotease activity and low proliferation of HCT166 cell line. SZ denotes individuals with schizophrenia whereas NS denotes non-schizophrenic individuals