Replacing critical point drying with hexamethyldisilazane drying enhances the ultrastructural preservation of cell surface projections in the parasite Trichomonas vaginalis for scanning electron microscopy
Fig 5
HMDS provides superior ultrastructural preservation of the amoeboid T. vaginalis surface (FMV1 strain) following adhesion to fibronectin-coated coverslips.
(A) Representative SEM images showing general and detailed views of parasites processed by CPD and HMDS drying. In CPD-dried sample, lamellipodia and pseudopods are retracted (white arrows), and disrupted filopodia and cytonemes are evident (orange arrowheads). An intact surface projection is indicated by a white arrowhead. No cytonemes are observed connecting adjacent parasites. In contrast, HMDS-dried sample display well-preserved, long cytonemes forming a network between adjacent parasites (white arrowheads), with few ruptured projections (orange arrowheads). Large, flattened lamellipodia and pseudopods are observed spreading across the substrate (*). (B) Quantification of the percentage of parasites displaying filopodia and/or cytonemes (top graph) and the percentage exhibiting disrupted surface projections (bottom graph) following CPD and HMDS drying. Bars represent mean ± standard deviation from three independent experiments performed in duplicate. 500 parasites were randomly counted per sample using SEM. *p < 0.05, Mann–Whitney U test. (C) Detailed SEM images highlighting differences in surface preservation between CPD- and HMDS-dried parasites. In CPD samples, numerous fragments resembling ruptured filopodia, cytonemes (orange arrowheads), lamellipodia, and blebs (★) are seen around a parasite. In HMDS, intact filopodia and cytonemes (white arrowheads) are seen extending from pseudopods and lamellipodia (*) of a parasite. Filopodia are also observed connecting lamellipodia (*) to large blebs (★), forming network-like arrangements (yellow arrowheads). Filopodia protruding from blebs are indicated by blue arrowheads. A cluster of projections at the posterior region of the parasites is indicated by a green arrow. Minor surface ruptures are indicated by an orange arrow. Ax, axostyle; U, uropod-like projection.