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In the developing vertebrate CNS, members of the Wnt gene family are characteristically expressed at signaling centers that pattern adjacent parts of the neural tube. To identify candidate signaling centers in the telencephalon, we isolated Wnt gene fragments from cDNA derived from embryonic mouse telencephalon. In situ hybridization experiments demonstrate(More)
The inducible expression of polyphenol oxidase (PPO), a presumed antiherbivore enzyme, was examined in hybrid poplar (Populus trichocarpa x Populus deltoides). Following mechanical wounding simulating insect damage, PPO activity increased dramatically in wounded and unwounded leaves on wounded plants beginning at 24 and 48 h, respectively. A hybrid poplar(More)
Prosystemin is the precursor protein of the 18 amino acid wound signal systemin which activates systemic defense in tomato leaves against insect herbivores (McGurl B, Pearce G, Orozco-Cardenas M, Ryan CA, Science 255 (1992) 1570–1573). Here, we report the isolation of cDNA sequences encoding prosystemin from potato (Solanum tuberosum), black nightshade (S.(More)
Polyphenol oxidase (PPO) is commonly believed to function as an effective antiherbivore defense in plants. PPO is induced in plants following herbivory, and insect performance is often negatively correlated with PPO levels. However, induced defenses create numerous changes in plants, and very little work has been done to test the direct effects of PPO on(More)
Hypocrellin, a photodynamic perylene quinonoid isolated from the Chinese medicinal fungus Hypocrella bambuase, was evaluated for antiviral activity against the human immunodeficiency virus (HIV-1). Hypocrellin was phototoxic to HIV-1, almost as good as the structurally similar plant pigment hypericin, and like hypericin its activity required visible light.(More)
Eight synthetic compounds related to the photosensitive antiviral quinonic plant compound hypericin were screened for light-mediated antiviral activity. The compound 2,5,9,12-tetra(carboxyethylthiomethyl) hypericin was found to have activity against membrane-enveloped Sindbis virus and murine cytomegalovirus but not against the non-enveloped poliovirus. The(More)
Peroxidases (PODs) are believed to act as induced and constitutive defenses in plants against leaf-feeding insects. However, little work has examined the mode of action of PODs against insects. Putative mechanisms include the production of potentially antinutritive and/or toxic semiquinone free radicals and quinones (from the oxidation of phenolics), as(More)
In an ethnopharmacological screening of medicinal plants used in Yunnan province of China, ethanol extracts from 31 plant species were assayed for inhibition of murine cytomegalovirus and Sindbis virus infections. Parallel assays were carried out with and without exposure to UVA radiation to test for photo-mediation of activity. Antiviral activity was(More)
Ascorbate is the major water-soluble antioxidant in plants and animals, and it is an essential nutrient for most insect herbivores. Therefore, ascorbate oxidase (AO) has been proposed to function as a plant defense that decreases the availability of ascorbate to insects. This hypothesis was tested by producing transgenic poplar (Populus tremula × Populus(More)
Transgenic hybrid aspen (Populus tremula x tremuloides) overexpressing the MYB134 tannin regulatory gene show dramatically enhanced condensed tannin (proanthocyanidin) levels, as well as shifts in other phenolic metabolites. A series of insect bioassays with forest tent caterpillars (Malacosoma disstria) and gypsy moth (Lymantria dispar) caterpillars was(More)