Effect of Methylene Blue and Illumination on the Process of Differentiation of the ProtozoanHerpetomonas Samuelpessoai

Abstract

Herpetomonas samuelpessoai is a non-pathogenic protozoan that shares important antigens with Trypanosoma cruzi (the agent of Chagas' disease) and which shows three developmental stages: promastigote, paramastigote and the highly differentiated form opisthomastigote. Due to the difficulties in obtaining the last form, its physiology and biochemistry are not well understood, and procedures which can induce the process of differentiation promastigote-opisthomastigote are desirable. In this work we show that illumination of H. samuelpessoai with white light in the presence of methylene blue and oxygen (photodynamic effect) triggers the process of differentiation in a very efficient manner (the cultures show up to 70 per cent of the cells in the opisthomastigote form). We also observed that illumination alone and incubation with methylene blue in the dark can trigger the process but in levels markedly lower than illumination in the presence of the dye.

Membrane‐Associated Polysaccharides Composition, Nutritional Requirements and Cell Differentiation in Herpetomonas roitmani: Influence of the Endosymbiont

“…roitmani the occurrence of opisthomastigote differentiated forms significantly increased (from 37 to 72%). This large portion of opisthomastigote forms paralleled that (70%) observed in H. samuelpessoai subjected to illumination with white light in the presence of methylene blue and oxygen (photodynamic effect) [7]. Taken together, these results show that cured H. roitmani and methylene blue-photodynamic sensitized H. samuelpessoai provide the highest level of promastigote-opisthomastigote transformation obtained up to now.…”

Proliferative opisthomastigote forms in Herpetomonas roitmani (Kinetoplastida: Trypanosomatidae)

“…Nothing is known about opisthomastigotes, a differentiating form in Herpetomonas. Such a lack of information is primarily due to the difficulties in obtaining large numbers of such forms (Castellanos et al 1985).…”