Effect of ultraviolet and gamma-radiation on Herpetomonas samuelpessoai.

A study was made about the influence of ultraviolet (UV) and gamma-radiations on Herpetomonas samuelpessoai grown either in a chemically defined or in a complex medium. Cells cultivated in defined medium were more sensitive to UV than those from complex medium, as estimated by inhibition of cellular growth. The effect of gamma-radiation, however, was independent of the media in which the cells were grown. Both radiations interfere with the plasma membrane as analysed by parameters such as excretion of cellular material and concanavalin-A-induced agglutination. Doses of UV which inhibit the cellular growth do not interfere with the plasma membrane. With gamma-radiation, however, doses which inhibit cellular growth also interfere with the plasma membrane. These results suggest that for certain applications UV radiation may be an advantage in vaccine production.

Localization of concanavalin A binding sites on the cell membrane of Herpetomonas samuelpessoai: influence of growth conditions.

Herpetomonas samuelpessoai agglutinates when incubated with concanavalin A (Con A). Agglutination involved binding of Con A to specific receptors as it was inhibited by alpha-methyl-D-mannoside. The pattern and the intensity of the agglutination as well as the localization of Con A-binding sites were influenced by the composition of the growth medium, growth temperature and time of incubation. Con A-binding sites were detected by using the Con A-horseradish peroxidase-diaminobenzidine technique.