Xanthene Dyes as Pesticides

Phototoxic chemicals produced by plants have been studied in a number of contexts, most notably as protective agents against mammalian and insect herbivores. Although there are commonalities in the responses of these two groups of herbivores to plant phototoxins, there are differences as well. Whereas a greater range of chemical classes has been demonstrated to display phototoxicity against insects, considerably more information is available on symptomology of phototoxicity and mechanisms of action in mammals. The commonalities include alterations in behavior following ingestion, notably photophobia, disruption of integumentary integrity following contact or ingestion, and metabolic detoxification following ingestion, in the case of furanocoumarins involving cytochrome P450 monooxygenases. Not yet known to exist in insects are phototoxin-mediated effects on sensory (particularly visual) systems and phototoxicity resulting from abnormal chlorophyll metabolism. In order to gain greater understanding of the ecological significance of phototoxin-mediated plant defense against both insects and mammals, there is a need for more studies centered on natural associations.

Section: Comparison Of Integumentary Effectsmentioning

confidence: 96%

Phototoxicity of plant secondary metabolites: Insect and mammalian perspectives

Berenbaum

1995

“…Xanthene dyes are believed to generate singlet oxygen [4] and also to be capable of free radical-type reactions [5]. Although the literature abounds with toxicological [6] and photochemical [7-91 investigations, relatively few studies have been performed on intact organisms to determine the mechanism of photodynamic action.…”

Section: Introductionmentioning

confidence: 99%

Glutathione depletion associated with rose bengal‐photosensitized mortality in the housefly, Musca domestica

Wages

Heitz

1987

Self Cite

Glutathione, pyridine nucleotides, and lipid peroxides were measured in adult houseflies following various regimens of dye treatment and light exposure. Comparisons were made between dark control and light control flies to judge the effect of light exposure alone; between dark control and dark, dye-treated flies to evaluate the effects of dye-feeding in the dark; and between dark, dye-treated and light, dye-treated flies to measure the effect of photodynamic action. No significant effect was observed in levels of NADC, NADH, or NADPC. However, a decrease (-16.7%) in NADPH during photodynamic treatment was measured. Relatively small inductions of glutathione were observed in light controls and dark, dye-treated flies. Depletion of both CSH and total glutathione (the sum of GSH and GSSG, expressed as GSH equivalents) occurred in light, dye-treated flies as compared to dark, dye-treated flies. Depletion of NADPH, when related to GSH depletion, suggested that GSH is being utilized to conjugate some products of photooxidation or that it is being directly oxidized to GSSG. However, the observation of a reduction in total glutathione also suggests that a fraction of GSH is being either oxidized to a product other than GSSG or irreversibly conjugated. No significant effects from photodynamic treatment on peroxidative potential or lipid hydroperoxides were observed.

“…As a class of enzymes, the SODs are of particular interest to us owing to their postulated ability of interacting with '02 and inhibiting its reaction [6,7] or by acting as protectant against the effects of ionizing radiation [4]. Specifically, xanthene dyes, known to generate '02 as part of their photooxidative reaction, are now in use as insecticides [8]. If SOD does afford a degree of protection to the organism that has been exposed to '02, a possible source of resistance to the pesticide may exist.…”

Section: Introductionmentioning

confidence: 99%

Superoxide dismutase in the housefly, Musca domestica (L.)

Bird

Salin

Boyle

et al. 1986

Self Cite

Four superoxide dismutase (SOD) (E.C. 1.15.1.1) isozymes were present in whole tissue homogenates of Musca domestica when examined by polyacrylamide gel electrophoresis. One of the isozymes contained manganese, and the other three contained copper and zinc. All were observed in each of the body tagma (head, abdomen, and thorax) and at each developmental stage (egg to adult). The copper‐ and zinc‐containing isozymes purified from newly emerged, adult M. domestica had a relative molecular weight of 34,800 as determined by gel filtration chromatography but consisted of two equal‐size subunits of 16,000 as measured by sodium dodecylsulfate polyacrylamide gel electrophoresis. An isoelectric point between 4.8 and 5.1 was measured. Approximately 2 mol each of copper and zinc were present per dimer. The three copper, zinc isozymes were identified as charge variants. The amino acid composition of the enzyme was similar to that of copper, zinc‐containing superoxide dismutases from other sources. Purified housefly copper, zinc superoxide dismutase was neither deactivated nor able to protect lactic dehydrogenase against deactivation in the presence of light and rose bengal, a known generator of singlet oxygen. The role of SOD in the phototoxic reaction involving rose bengal is discussed.