On turning green into gold

Journal ArticleAnthropogenic effects on the climate and biodiversity of our planet are among the most troubling and perhaps irreversible threats facing scientists, policymakers, and citizens. Yet many scientists are reluctant or unsure of how to apply their expertise in basic science to these pressing real-world problems

Between-species differences in leaf defenses of tropical trees

Journal ArticleRates of herbivory and patterns of leaf defense are presented for light-demanding and shade-tolerant tree species growing in a lowland rainforest in Panama. More than 85 percent of the annual leaf damage is due to grazing by insects. There are over three orders of magnitude difference between species in the rates of herbivory on mature leaves. More than 70 percent of this variation can be statistically explained by measured defenses

Intraspecific variation in herbivory on two tropical tree species

Journal ArticleLevels of herbivory on young and mature leaves were determined for two tree species, Trichilia cipo (Meliaceae) and Cecropia insignis (Moraceae), in a lowland rain forest of Panama. Saplings of both species were studied in light gaps, and in addition, Trichilia was studied in the understory

Herbivory and defensive characteristics of tree species in a lowland tropical forest

Journal ArticleRate of herbivory and defensive characteristics of young and mature leaves were measured for saplings of 46 canopy tree species in a lowland tropical rain forest (Barro Colorado Island, Panama). Grazing rates were determined in the field for sample periods in the early wet, late wet, and dry seasons. Leaf properties such as pubescence, toughness, water, protein, fiber, and phenolic contents explained over 70% of the variation among plant species in the rates of herbivory on mature leaves. Leaf toughness was most highly correlated with levels of herbivory, followed by fiber content and nutritive value. Phenol content and phenol : protein ratios were not significantly correlated with damage

Rates of herbivory on different tropical trees

Book ChapterRates of herbivory on marked young and mature leaves from saplings of 21 canopy tree species were measured in the wet and dry seasons. Species were classified into two life history groups: persistent species which are found throughout the shaded understory, and pioneer species which only become established in light gaps created by fallen trees. Mature leaves of slow-growing persistent species were eaten by insects at an average annual rate of 21%, whereas rapidly growing pioneer species were grazed 4 times faster in the dry season and 10 times faster in the wet

What's up? Perspectives from the first international forest canopy conference at Sarasota, Florida, 1994

Journal ArticleJumars, caribineers, pole pruners, tree bicycles, Bosun's chairs, booms, peconhas . . . these terms are not listed in most biological dictionaries. Nor are construction cranes or large treehouses or hot-air dirigibles listed as priority equipment for any scientific laboratories. But these are the essential tools required to provide some of the exciting results reported at the recent First International Forest Canopy Conference during November 1994 at The Marie Selby Botanical Gardens in Sarasota, Florida

Novel DNA-based microfluorimetric method to evaluate antimalarial drug activity

Journal ArticleThis paper describes the development of a novel microfluorimetric assay to measure the inhibition of Plasmodium falciparum based on the detection of parasitic DNA by intercalation with PicoGreen®. The method was used to determine parasite inhibition profiles and 50% inhibitory concentration values of known or potential antimalarial drugs. Values for parasite inhibition with known anti-malarial drugs using the PicoGreen® assay were comparable with those determined by the standard method based upon the uptake of 3H-hypoxanthine and the Giemsa stain microscopic technique

Chemical and bioactive natural products from microthyriaceae sp., an endophytic fungus from a tropical grass

pre-printIn screening for natural products with antiparasitic activity, an endophytic fungus, strain F2611, isolated from above-ground tissue of the tropical grass Paspalum conjugatum (Poaceae) in Panama, was chosen for bioactive principle elucidation. Cultivation on malt extract agar (MEA) followed by bioassay-guided chromatographic fractionation of the extract led to the isolation of the new polyketide integrasone B (1) and two known mycotoxins, sterigmatocystin (2) and secosterigmatocystin (3). Sterigmatocystin (2) was found to be the main antiparasitic compound in the fermentation extract of this fungus, possessing potent and selective antiparasitic activity against Trypanosoma cruzi, the cause of Chagas disease, with an IC50 value of 0·13 μmol l−1. Compounds 2 and 3 showed high cytotoxicity against Vero cells (IC50 of 0·06 and 0·97 μmol l−1, respectively). The new natural product integrasone B (1), which was copurified from the active fractions, constitutes the second report of a natural product possessing an epoxyquinone with a lactone ring and exhibited no significant biological activity

Divergent defensive strategies of young leaves in two species of Inga

Journal ArticleIn the recently radiated genus Inga (Fabaceae), few nucleotide substitutions have accumulated among species, yet large divergences have occurred in defensive phenotypes, suggesting strong selection by herbivores. We compared herbivory and defenses of young leaves for I. goldmanii, a more derived species that follows a "defense" strategy, and I. umbellifera, a more basal species that follows an "escape" strategy

Coibanoles, a new class of meroterpeniods produced by pycnoporus sanguineus

ManuscriptThree new terpenoids of mixed biosynthetic origin were isolated from the culture filtrate of the endophytic fungus Pycnoporus sanguineus. Their structures were determined by extensive spectroscopic analyses. We have named these tricyclic and tetracyclic metabolites ?coibanoles A?C? in reference to Coiba Island and Coiba National Park, Panam?, from which the plant and endophyte were collected. The extract was inactive to the human parasites Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum at a test concentration of 10 ?g/mL