Pollen from the Acacia has been reported as an important source of pollinosis in tropical and subtropical regions of the world. The aim of this study was to characterize the IgE binding protein of Acacia farnesiana pollen extract and evaluate cross-reactivity with the most allergenic pollens. In this study, pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting and specific ELISA using forty-two Acacia allergic patients. Potential cross-reactivity among Acacia and selected allergenic plants was evaluated with ELISA and immunoblotting inhibition experiments. There were several resolved protein fractions on SDS-PAGE which ranged from 12 to 85 kDa. Several allergenic protein bands with molecular weights approximately between 12 and 85 kDa were recognized by IgE-specific antibodies from Acacia allergic patients in the immunoblot assay. The inhibition by the Prosopis juliflora pollen extract was more than those by other pollen extracts. Moreover, the wheal diameters generated by the Acacia pollen extract were highly correlated with those of P. juliflora pollen extracts. The findings suggest that several proteins such as 15, 23, 45, and 50 kDa proteins could be used as diagnostic and therapeutic reagents for patients allergic to A. farnesiana and P. juliflora.

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Morphological changes of a toxigenic isolate of Aspergillus parasiticus cultured in the presence of aqueous leaf and seed extracts obtained from neem, Azadirachta indica A. Juss (syn. Melia azadirachta L.), a potent inhibitor of aflatoxin biosynthesis, was studied. Mycelial samples obtained from A. parasiticus cultures exposed to an effective concentration of the leaf and seed extracts (50% v/v in culture media) produced approximately 90 and 75%, less aflatoxins respectively. Under these conditions semi-thin longitudinal and cross sections of the mycelia and vesicles showed attenuation of the cell wall at variable intervals causing deformation of the mycelium, vacuolation of the mycelial cytoplasm and vesicles. Herniation of the cytoplasmic contents which were protruding from the mycelium resulting in irregular mycelial shape. In addition, some mycelia showed a cleft between the cell wall and cytoplasm. Data obtained from microscopic observations may suggest that irreversible inhibition in aflatoxin biosynthesis by fungi due to neem extracts is partly due to mycelial cell wall damages.