The relation has been studied between the high molecular weight glutenin (HMWg) subunit alleles and the bread-making quality of 226 lines of winter wheat (T. aestivum L.), grown in The Netherlands. The lines represented a wide range of genetic backgrounds, and had not been selected for quality, in contrast to the established varieties used by other authors.The variation in HMWg subunit genotypes accounted for about 20% of the total variation in loaf volume among the lines. Most important was the allelic variation at the Glu-D1 locus. The Glu-D1 allele encoding the subunits 5 + 10 was superior to its allelic counterpart, encoding 2 + 12. The difference in average of loaf volume between groups of lines containing 5 + 10 or 2 + 12 was negatively related with protein content of the flours. When protein content was below 9.2%, no effect of allelic variation at the Glu-D1 locus was present. Epistatic effects between the Glu-I loci also contributed to the variation in loaf volume of the lines: i.e. the effect of allelic variation at Glu-A1 and Glu-B1 depended on the allele present at the Glu-D1. The contribution of the epistatic effects was about half the contribution of the additive effects, and should therefore be included in predictive models for bread-making quality.

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The compositions of glycosidic-bound steroidal alkaloids (SA) of Solanum species used in potato breeding were assessed by capillary gas chromatography using simultaneous nitrogen-specific (NPD) and flameionisation detection (FID) . High concentrations of solanidine glycosides and other steroidal glycoalkaloids, amongst which the teratogenic SA solasodine, were found in tubers and leaves of wild species . In addition unidentified compounds were found, which were most probably SA as was shown by their NPD/FID response ratios . The total glycoalkaloid contents varied from 123 to 7348 mg/kg fresh weight . Tubers of cultivars, corresponding in small size and grown under the same conditions as tubers of the wild species, showed contents of solanidine glycosides which were 2-3 times higher than those of field-grown normal tubers (126-721 vs 40-360 mg/kg fresh weight, respectively) . In some cases the SA compositions of the tubers were markedly different from those of the leaves of the same plant or they varied between accessions of the same species . Also the growing conditions appeared to influence the composition quantitatively and qualitatively .The consequences for potato breeding of utilizing wild Solanum species containing potentially hazardous levels of SA are discussed .

Colloidal carbon particles can serve as label in sol particle immunoassays. The universal applicability of these particles in qualitative and (semi)quantitative immunoassays has been demonstrated. Sol particle and/or dipstick immunoassays, not yet optimized in terms of sensitivity, are discussed. The colloidal label has been used successfully in a mouse immunoglobulin isotyping kit. Human serum albumin spotted onto nitrocellulose in a concentration range of 7.8 to 1000 ng could be detected using anti-albumin antibody absorbed onto colloidal carbon particles. It was also possible to perform a competitive assay with this conjugate for a concentration range of free human serum albumin varying from 0.25 to 6.75 micrograms. The Kunitz-type trypsin inhibitor from soybean was determined by a colloidal carbon based immunoassay in a range of 2.5 to 160 ng. In this assay, free and colloidal carbon-bound inhibitor competed for binding specific antibodies spotted onto a nitrocellulose membrane. An image- and data-processing procedure has been developed that enables a rapid and simple quantification of colloidal carbon sol particle immunoassays. The average grey level of a spot is taken as a measure for quantitative purposes. This so-called Sol-particle Image Processed ImmunoAssay (SIPIA) procedure is equally well applicable to assays using other colloidal particles.

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