Distinguishing Activities in the Photodynamic Arsenals of the Pigmented Ciliates Blepharisma sinuosum Sawaya, 1940 and Blepharisma japonicum Suzuki, 1954 (Ciliophora: Heterotrichea)

AbstractBlepharismins are photodynamic hypericin ‐like dianthrones produced as a variable pigment blend inBlepharisma ciliates and mostly studied in the Afro ‐AsiaticB. japonicum. The present work describes the bioactivy of pigments from the BrazilianB. sinuosum. Comparative analyses showed that the pigments from both species can trigger photo ‐induced modifications in phospholipids, but different redox properties and biological activities were assigned for each pigment blend. Stronger activities were detected forB. sinuosum pigments, with the lethal concentration LC50 10 × lower thanB. japonicum pigments in light irradiated tests againstBacillus cereus and less than half for treatments on the human HeLa tumor cells. HPLC showedB. sinuosum producing a simpler pigment blend, mostly with the blepharismin ‐C (~70%) and ‐E (~30%) types. Each blepharismin engaged a specific dose‐response profile on sensitive cells. The blepharismin‐B and ‐C were the most toxic pigments, showing LC50 ~2.5 –3.0 µM and ~100 µM onB. cereus and HeLa cells, respectively, after illumination. Similarity clustering analysis compiling the bioactivity data revealed two groups of blepharismins: the most active, ‐B and ‐C, and the less active, ‐A, ‐D and ‐E. TheB. sinuosum pigment blend includes one representative of each clade. Functional and medical implications are discussed.

Source: Photochemistry and Photobiology - May 29, 2020 Category: Science Authors: J éssica Cavaleiro, Nathally B. Oliveira, Talita A. Ribeiro, Lohaine F. Guimarães, Noemi M. Fernandes, Inacio D. da Silva‐Neto, Flávia Marszaukowski, Karen Wohnrath, Cleber B. Barreto, Michael Schweikert, Giulio Petroni, Claudio Ortenzi, Tags: RESEARCH ARTICLE Source Type: research