Photostabilization of an entomopathogenic fungus using composite clay matrices.

Citation:

Cohen E, Joseph T, Kahana F, Magdassi S. Photostabilization of an entomopathogenic fungus using composite clay matrices. Photochem. Photobiol.Photochemistry and Photobiology. 2003;77 (2) :180 - 185.

Date Published:

2003///

Abstract:

To provide photostabilization for entomopathogenic fungi by anionic dyes, composite matrixes based on clay-biopolymer combinations were prepd. In the first step, the neg. surface charge of various clays (montmorillonite, attapulgite, bentonite and kaolinite) was reversed to pos. by adsorption to the polycationic biopolymer chitosan. The second step involved adsorption of the toxicol. safe anionic dyes fast green (FG) and naphthol yellow S (NYS) to the clay complexes. Compared with cytotoxic photoprotectants like berberine, palmatine and acriflavine, the anionic dyes have no adverse effects up to a concn. of 1 M. In assays using various clay-chitosan-dye matrixes and UV irradn. from a lamp source, it was evident that both FG and NYS provided considerable photostabilization for conidia of the entomopathogenic fungus Aschersonia spp. that served as a model biocontrol agent. Because of the light-dispersing property, bentonite and attapulgite per se provided significant photoprotection. All clay matrixes contg. FG provided a substantial photostabilization effect. [on SciFinder(R)]