Studies with chemically modified cholera toxin derivatives showed that all treatments that decreased the ability of toxin to bind to mouse thymus cells or to polystyrene-coupled GM1 ganglioside caused a concomitant reduction in the toxin's ability to increase adenosine 3':5'-cyclic phosphate (cyclic AMP) in thymus cells and skin vascular permeability in rabbits. Dissociation of the H (heavy) an...

Understanding the complex mechanisms controlling treeline advance or retreat in the arctic and subarctic has important implications for projecting ecosystem response to changes in climate. Changes in landcover due to a treeline biome shift would alter climate feedbacks (carbon storage and energy exchange), ecosystem services such as wildlife and berry habitat, and landscape flammability. Wildfi...

Seed dispersal and environmental heterogeneity, the effects of their interaction, are perceived to be determinants spatial patterns trees. We applied point process analyse Vatica odorata (Griff.) Symington (Dipterocarpaceae) in Cuc Phuong National Park Vietnam understand its patterns, decipher main factors affecting seedling establishment species. established a total 12 replicated plots, each w...

in order to study the effect of elevation on quantitative and qualitative characteristics of the humid forests of guilan shafaroud, series 17, 16 and 7 were selected that fall in to three height classes; class 1 (‏less than 500 m), class 2 (‏500 – 1000 m) and class 3 (‏1000 – 1600 m). in height class 1, 2 and 3 sample plots were determined as 4, 15 and 20 respectively and each sample plot was 0...

Fire and the invasive annual grass Microstegium vimineum in eastern deciduous forests" (2012). Abstract Non-native plant invasions have the potential to change natural and prescribed fire regimes by increasing fuel loads, continuity of fuels, and fuel composition, which may alter fire intensity, damage native species, and promote further invasions. In this project we sought to evaluate the inte...

In order to investigate the seasonal changes and the possible role of the free polyamines in the leaves and stems on the alternate bearing habit of the ‘Kinnow’ mandarin (Citrus reticulata Blanco) trees, a comparative study was conducted to analyze the levels of free polyamines  (putrescine, spermidine and spermine) in the leaves and stems tissues of “on” and &ldquo...

Chemical analyses were conducted to determine the qualitative and quantitative differences in monoterpenes and sesquiterpenes in plant material from avocado trees, Persea americana Mill. (Lauraceae). The initial study analyzed plant material sampled from the trunk to the leaves through different branch diameters to quantify proximo-distal spatial differences within a tree. All trees were seedli...