The allergenic proteins of mould, Rhizopus nigricans extract (RNE) were identified and characterized by crossed immunoelectrophoresis (CIE), thin-layer isoelectrofocusing (TLIEF) and RAST inhibition. CIE revealed that the extract contained at least 31 distinct antigens. On TLIEF the extract resolved into 22 bands in pI 3.5-6.8. Two important allergens, Rhiz IIIb and VIb were purified by a combination of ammonium sulfate precipitation, anion exchange chromatography on DEAE-Sephadex column and gel filtration. Twenty and 12 micrograms of Rhiz IIIb and Rhiz VIb were sufficient to give 50% RAST inhibition as against 43 micrograms of crude RNE. Rhiz IIIb and Rhiz VIb were found to be glycoproteins with molecular weights of 12,400 daltons and 14,200 daltons, respectively. Rhiz IIIb was found to be homogeneous on polyacrylamide gel electrophoresis (PAGE) and TLIEF with a pI of 4.8, while Rhiz VIb gave a single band on PAGE and resolved into two Coomassie blue stained bands with pI 3.6 and 3.8. It was possible to separate the components of RNE on fast protein liquid chromatography (FPLC) using an anion exchanger Mono Q column. The identification and characterization of the antigenic and allergenic proteins in the extract will be useful in standardization of RNE and in preparation of an in-house reference standard.

Dyestuff workers coming in contact with benzanthrone (an intermediate used for the synthesis of a variety of dyes) develop skin lesions, gastritis, liver malfunctions, and sexual disturbances. A highly sensitive fluorometric method to monitor trace quantities of benzanthrone in urine, serum, and biological tissues for experimental studies, has been developed. Coupled with simple extraction and resolution, optimum fluorescence is obtained in an equal mixture of chloroform:methanol, detecting as low as 2 ng benzanthrone. This method is approximately 250 times more sensitive than currently available colorimetric assay.

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Workers exposed to dye intermediate, benzanthrone, develop itching, burning sensation, erythema and hyperpigmentation of the skin; which also becomes tender, rough and peals off easily. Earlier experiments have shown that rat skin is capable of picking up benzanthrone. The present study was, therefore, aimed to explore the binding kinetic of skin matrix, of which collagen shares the major proportion. Results revealed that benzanthrone readily binds to reconstituted native collagen fibrils. The uptake is concentration dependent initially and does not involve-SH groups. Denaturation (gelatinisation) of collagen by heat or urea treatment leads to loss of its binding potential. Serum albumin exhibits a tendency to dissociate benzanthrone prebound to collagen and thus may ultimately assist in efflux of benzanthrone through circulation.