A basic allergen fraction isolated from Alternaria extracts by preparative flat-bed gel isoelectric focusing (as previously reported) was subjected to further characterization. The fraction was chromatographed on a Sephadex G-25 column and exhibited two major peaks, the first of which was allergenic and the second of which was nonallergenic but caused a precipitate to form when added to a mixture of sodium dodecyl sulfate (SDS) (1 %) and trichloroacetic acid (5%). SDS-PAGE indicated that the allergen component of the basic fraction migrated at about the same rate as insulin (5.8 kdaltons). Both G-25 peaks were carbohydrate rich with a proteinxarbohydrate ratio (by weight) of 1:4.5 and 1:5.8 for peak 1 and peak 2 respectively. Heat (100°C for 10 min) and enzyme digestion (trypsin, α-chymotrypsin and pepsin) did not reduce the RAST inhibition values for peak 1 or the original basic fraction. The basic fraction did not bind human IgE specific for birch pollen indicating that the RAST inhibition and IgE (Alternariaspecific) binding to radioimmunoelectrophoresis plates was not due to nonspecific binding of IgE. We conclude that the allergenicity of the basic fraction is due to a small molecule that is predominantly carbohydrate in nature and is a major allergen of Alternaria.
When studying the role of plant hormones in the control of growth at apical meristems, it is often difficult to obtain needed amounts of physiologically uniform buds. A source and method are described for obtaining sufficient quantities of large, uniform buds and for the treatment of the buds with indoleacetic acid and kinetin. Buds from the root system of Euphorbia esula L. were grown in Petri plates, with agar suspending the short root sections from which they emanate. Plant hormones are applied by their incorporation in the agar. The effect of various concentrations of indoleacetic acid and kinetin on bud growth was examined. a trough cut from sterile agar in a Petri plate. The initial height of the buds should be 0.5 mm to aid uniformity in growth initiation. Growth of the buds, which were "naturally suppressed" due to apical dominance on an intact plant, usually begins in 2 to 4 days after transfer to the agar plates. Growth continues for several days, depending on the amount of nutrient stored in the root sections. Plant growth regulators (IAA and kinetin) were incorporated into agar to determine the concentrations required for the inhibition of growth initiation and inhibition of logarithmic growth. Figure 1 indicates the effect of various concentrations of IAA or kinetin or both (incorporated into agar) on growth When plants or plant parts are treated with excessive dosages of plant hormones, a growth inhibitory response is usually observed (4). Comparatively little research has been directed towards determining the cause of this growth inhibition induced by hormones that stimulate plant growth at low concentrations. In order to understand the mechanism of hormone action, the inhibition, as well as the enhancement of growth, must be considered. Previous literature indicates that bud growth is under the control of at least two plant hormones (auxin and cytokinin) that normally stimulate growth (4)(5)(6)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.