A glycopeptide containing a triantennary N-linked oligosaccharide from fetuin was modified by a series of chemical and enzymic reactions to afford a reagent that contained a terminal residue of 6-(N-methylamino)-6-deoxy-D-galactose on one branch of the triantennary structure and terminal galactose residues on the other two branches. Binding assays and gel filtration experiments showed that this modified glycopeptide could bind to the sugar-binding sites of ricin. The ligand was activated at the 6-(N-methylamino)-6-deoxy-D-galactose residue by reaction with cyanuric chloride. The resulting dichlorotriazine derivative of the ligand reacts with ricin, forming a stable covalent linkage. The reaction was confined to the B-chain and was inhibited by lactose. Bovine serum albumin and ovalbumin were not modified by the activated ligand under similar conditions, and we conclude, therefore, that the reaction of the ligand with ricin B-chain was dependent upon specific binding to sugar-binding sites. Ricin that had its galactose-binding sites blocked by the covalent reaction with the activated ligand was purified by affinity chromatography. The major species in this fraction was found to contain 2 covalently linked ligands per ricin B-chain, while a minor species contained 3 ligands per B-chain. The cytotoxicity of blocked ricin was at least 1000-fold less than that of native ricin for cultured cells in vitro, even though the activity of the A-chain in a cell-free system was equal to that from native ricin. Modified ricin that contained only 1 covalently linked ligand was also purified. This fraction retained an ability to bind to galactose affinity columns, although with a lower affinity than ricin, and was only 5- to 20-fold less cytotoxic than native ricin.

No abstract

Robert Brown's interpretation of the epigynous glands of Zingiberaceae as derived from two out of the three members of an inner androecial whorl, the third member being the posterior functional stamen, has been held as probably correct for many years. Studies on many members of this family, both Indian and foreign, proved that the epigynous glands in this family are special vascularized upward growths from intramarginal portions of the carpels. These portions more or less correspond to two of the three septa of the ovary. The glands are antero-lateral in position. Abnormal flowers of many species confirmed the conclusions drawn from normal flowers.

The effect of low‐dose gamma irradiation (0.25–1.00 kGy) on pre‐packed whole‐wheat flour (atta) was assessed in terms of physico‐chemical properties, nutritional quality, chapati‐making quality and sensory attributes. Semi‐pilot scale storage studies on irradiated pre‐packed whole‐wheat flour revealed that there was no adverse effect of irradiation and storage up to 6 months of whole‐wheat flour treated at doses up to 1.00 kGy on total proteins, fat, carbohydrates, vitamin B1 and B2 content, colour index, sedimentation value, dough properties, total bacterial and mould count. Storage of wheat flour resulted in slight increase in moisture, free fatty acids, damaged starch, reducing sugars and slight decrease in gelatinization viscosity. However, irradiation as such had no effect on any of these parameters. Irradiation at 0.25 kGy was sufficient to extend the shelf‐life of atta up to 6 months without any significant change in the nutritional, functional attributes. Chapaties made from irradiated atta (0.25 kGy) were preferred even after 6 months storage, compared with the control.

No abstract

No abstract

The Apostasiaceae is a small family of limited distribution, with about 15 species altogether, and its affinities have been controversial. The floral anatomy of nine representatives of the family is now known in detail, and its relationships are discussed on the basis of the floral vasculature. The pattern of the vascular supply to the floral organs is very similar to that of the diandrous orchids, showing the undoubted affinity of the Apostasiaceae with the Orchidaceae. The subtribe Cypripedilinae of the Orchidaceae must have evolved directly from the Apostasiaceae.

No abstract