Comparing relative rates of pollen and seed gene flow in the island model using nuclear and organelle measures of population structure. (1/12)

We describe a method for comparing nuclear and organelle population differentiation (F(ST)) in seed plants to test the hypothesis that pollen and seed gene flow rates are equal. Wright's infinite island model is used, with arbitrary levels of self-fertilization and biparental organelle inheritance. The comparison can also be applied to gene flow in animals. Since effective population sizes are smaller for organelle genomes than for nuclear genomes and organelles are often uniparentally inherited, organelle F(ST) is expected to be higher at equilibrium than nuclear F(ST) even if pollen and seed gene flow rates are equal. To reject the null hypothesis of equal seed and pollen gene flow rates, nuclear and organelle F(ST)'s must differ significantly from their expected values under this hypothesis. Finite island model simulations indicate that infinite island model expectations are not greatly biased by finite numbers of populations (>/=100 subpopulations). The power to distinguish dissimilar rates of pollen and seed gene flow depends on confidence intervals for fixation index estimates, which shrink as more subpopulations and loci are sampled. Using data from the tropical tree Corythophora alta, we rejected the null hypothesis that seed and pollen gene flow rates are equal but cannot reject the alternative hypothesis that pollen gene flow is 200 times greater than seed gene flow.  (+info)

New triterpene isolated from Eschweilera longipes (Lecythidaceae). (2/12)

The phytochemical studies of Eschweilera longipes Miers (Lecythidaceae) have led to the identification of a new triterpene 3beta, 24-dihydroxyfriedelane, the known 1beta, 2beta, 3beta, 19beta-tetrahydroxyurs-12-en-28-oic acid (1beta-hydroxyeucaphic acid) besides the saponin sitosterol 3betaO-betaD-glucopyranoside. The structures were established from the IR, NMR and mass spectra data including 2D NMR experiments of natural substances and of the acetyl derivative of the new triterpene.  (+info)

Patterns and relative rates of nucleotide and insertion/deletion evolution at six chloroplast intergenic regions in new world species of the Lecythidaceae. (3/12)

Insertions and deletions (indels) in chloroplast noncoding regions are common genetic markers to estimate population structure and gene flow, although relatively little is known about indel evolution among recently diverged lineages such as within plant families. Because indel events tend to occur nonrandomly along DNA sequences, recurrent mutations may generate homoplasy for indel haplotypes. This is a potential problem for population studies, because indel haplotypes may be shared among populations after recurrent mutation as well as gene flow. Furthermore, indel haplotypes may differ in fitness and therefore be subject to natural selection detectable as rate heterogeneity among lineages. Such selection could contribute to the spatial patterning of cpDNA haplotypes, greatly complicating the interpretation of cpDNA population structure. This study examined both nucleotide and indel cpDNA variation and divergence at six noncoding regions (psbB-psbH, atpB-rbcL, trnL-trnH, rpl20-5'rps12, trnS-trnG, and trnH-psbA) in 16 individuals from eight species in the Lecythidaceae and a Sapotaceae outgroup. We described patterns of cpDNA changes, assessed the level of indel homoplasy, and tested for rate heterogeneity among lineages and regions. Although regression analysis of branch lengths suggested some degree of indel homoplasy among the most divergent lineages, there was little evidence for indel homoplasy within the Lecythidaceae. Likelihood ratio tests applied to the entire phylogenetic tree revealed a consistent pattern rejecting a molecular clock. Tajima's 1D and 2D tests revealed two taxa with consistent rate heterogeneity, one showing relatively more and one relatively fewer changes than other taxa. In general, nucleotide changes showed more evidence of rate heterogeneity than did indel changes. The rate of evolution was highly variable among the six cpDNA regions examined, with the trnS-trnG and trnH-psbA regions showing as much as 10% and 15% divergence within the Lecythidaceae. Deviations from rate homogeneity in the two taxa were constant across cpDNA regions, consistent with lineage-specific rates of evolution rather than cpDNA region-specific natural selection. There is no evidence that indels are more likely than nucleotide changes to experience homoplasy within the Lecythidaceae. These results support a neutral interpretation of cpDNA indel and nucleotide variation in population studies within species such as Corythophora alta.  (+info)

Antitumor activity and antioxidant status of the methanol extract of Careya arborea bark against Dalton's lymphoma ascites-induced ascitic and solid tumor in mice. (4/12)

Based on the ethnomedical use of Careya arborea Roxb bark in the treatment of tumors, the present study was carried out to evaluate the anticancer potentials against Dalton's lymphoma ascites (DLA)-induced ascitic and solid tumors. The methanol extract of its bark given orally to mice at the dose of 250 or 500 mg/kg body weight for 10 days caused significant reduction in percent increase in body weight, packed cell volume, and viable tumor cell count when compared to the mice of the DLA control group. Restoration of hematological and biochemical parameters towards normal was also observed. Histological observations of liver and kidney also indicated repair of tissue damage caused by tumor inoculation. The extract at the dose of 5 or 25 mg/kg body weight given i.p. daily for 14 days significantly reduced the solid tumor volume induced by DLA cells.  (+info)

First record of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), in Para nut, Bertholletia excelsa (Lecythidaceae). (5/12)

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Anti-inflammatory, antinociceptive, and antipyretic effects of methanol extract of Cariniana rubra stem bark in animal models. (6/12)

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Effects of Lecythis pisonis Camb. (Lecythidaceae) in a mouse model of pruritus. (7/12)

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Antimicrobial, antimycobacterial and antibiofilm properties of Couroupita guianensis Aubl. fruit extract. (8/12)

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