Dale G. Nagle

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Antifungal compounds exert their activity through a variety of mechanisms, some of which are poorly understood. Novel approaches to characterize the mechanism of action of antifungal agents will be of great use in the antifungal drug development process. The aim of the present study was to investigate the changes in the gene expression profile of(More)
The compound (-)-epigallocatechin-3-gallate (EGCG) is the major catechin found in green tea [Camellia sinensis L. Ktze. (Theaceae)]. This polyphenolic compound and several related catechins are believed to be responsible for the health benefits associated with the consumption of green tea. The potential health benefits ascribed to green tea and EGCG include(More)
Pure natural products isolated from marine sponges, algae, and cyanobacteria were examined for antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay and a 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) cellular-based assay. The DCFH system detects only antioxidants that penetrate cellular membranes.(More)
Originally purified as a major lipid component of a strain of the cyanobacterium Lyngbya majuscula isolated in Curaçao, curacin A is a potent inhibitor of cell growth and mitosis, binding rapidly and tightly at the colchicine site of tubulin. Because its molecular structure differs so greatly from that of colchicine and other colchicine site inhibitors, we(More)
Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that promotes tumor cell adaptation and survival under hypoxic conditions. HIF-1 is currently recognized as an important molecular target for anticancer drug discovery. A T47D breast tumor cell-based reporter assay was used to evaluate the NCI Open Repository of marine invertebrates and algae(More)
A new bioassay has been developed combining the simplicity of direct bioautography with the improved chromatographic resolution of 2D-TLC. Mixtures of structurally diverse antifungal agents were tested to establish the validity and utility of this method in the discovery of new natural products with activity against agriculturally important fungal pathogens.
Our previous research has shown that many red algae metabolize polyunsaturated fatty acids to oxidized products resembling the eicosanoid hormones from mammals. We have extended these studies to members of the Phaeophyceae and Chlorophyta and find they also possess similar biosynthetic pathways. From several we have identified novel prostaglandin-like(More)
Curacin A, the major lipid constituent of a strain of the marine cyanobacterium Lyngbya majuscula obtained off the coast of Curaçao, is a potent antimitotic agent that we have previously shown to inhibit microtubule assembly and colchicine binding to tubulin. In the present study, we report that curacin A probably binds in the colchicine site because it(More)
Antifungal bioassay-guided isolation of the ethanol extract of the roots of Pentagonia gigantifolia yielded 6-octadecynoic acid (1) and the new 6-nonadecynoic acid (2). Compounds 1 and 2 inhibited the growth of fluconazole-susceptible and -resistant Candida albicans strains. Their antifungal potencies were comparable to those of amphotericin B and(More)
A new solid tumor selective cytotoxic analogue of dolastatin 10 (1) has been isolated from the marine cyanobacterium Symploca hydnoides, collected near Guam. This metabolite has been assigned the trivial name symplostatin 1 (2). This discovery supports the proposal that many compounds isolated from the seahare Dolabella auricularia, the original source of(More)