Six fungi, Pestalotiopsis westerdijkii QM:381, Myrothecium verrucaria QM:460, Aspergillus terrus QM:72f, Chaetomium globosum QM:459, Basidiomycetes sp. QM:806, Trichoderma viride QM:6a were screened according to their ability to elaborate an extracellular enzyme system which has the highest soy fiber-degrading activity and the highest carboxymethylcellulase activity. Pestalotiopsis westerdijkii QM:481 gave the most potent extracellular enzyme system. When Pestalotiopsis westerdijkii was grown on a wheat bran medium at a temperature of 31.5°C for ten days, it elaborated the most potent extracellular enzyme system. It was found that the optimum conditions for this extracellular enzyme system, acting on soy residue for the purpose of making soy residue protein available for extraction, were pH 4.6 and 38°C. Treating one gram of soy residue, 40 ml (32 mg Nitrogen) enzyme preparation, at the optimum pH and temperature for 20 hours caused the most efficient extraction of protein. There was an increase in the amount of soluble carbohydrates, reducing sugars, glucose and galactose due to the action of enzyme on soy residue. The amount of non-protein nitrogen in the extractable fraction of soy residue after treatment with enzyme preparation or water increase with the increase of incubation time even in the presence of toluene which prevents bacterial contamination. This is probably due to the action of proteases from the soybean and enzyme preparation. In large scale experiments, when 40 ml (32 mg Nitrogen) of the enzyme preparation per gram of soy residue were used, about 60% of the soy residue protein was made available for water extraction and the yield of extractable protein in soy milk was increased by 20%. Feeding experiments using treated or untreated soy residue and soy milk showed that the treated milk contains protein of higher quality and better digestibility when compared to untreated soy milk or treated residue. The most limiting amino acid in these products is methionine. The amino acid composition of these products was very much the same. / Ph. D.

In this study we assayed the extent of genetic variation for five microsatellites in 94 accessions of wild (Glycine soja) and cultivated soybean (G. max). F₂ segregation analysis indicated that all five of the microsatellites were independently inherited and four loci were located in four independent linkage groups. The number of alleles per microsatellite locus ranged from five to 21. Overall, 43 more microsatellite alleles were detected in wild than in cultivated soybean. Allelic diversity for microsatellite loci was significantly higher in wild than in cultivated soybean. In a second study, molecular markers were used to identify and characterize quantitative trait loci (QTL) controlling seed weight in soybean, and to extend reports of orthologous seed weight genes in the genus Vigna to the genus Glycine by "comparative QTL mapping". DNA samples from 150 F₂ individuals from an interspecific soybean cross were analyzed with 91 genetic markers. Three and five markers were significantly associated with seed weight variation (P<0.01) in the F₂ and F_2:3 generations, respectively. Two-way ANOVA tests for digenic interactions identified three significant epistatic interactions in both generations. In a combined analysis, the significant marker loci and epistatic interactions explained 50 and 60% of the total variation for seed weight in the F₂ and F_2:3 generations, respectively. Comparison of our results in Glycine with those reported in Vigna indicated that both genera share orthologous seed weight genes. Moreover, a significant epistatic interaction between seed weight QTLs was conserved in both genera. The objective of the third study was to use molecular markers and interval mapping techniques to position and characterize quantitative trait loci controlling seed protein, oil, sucrose, and calcium content as well as seed weight in soybean. Two QTLs were detected for protein and calcium content, five for oil content and seed weight and six for sucrose content, respectively. Percent phenotypic variation explained by these individual QTLs ranged from 6.6 to 34.0%. The total phenotypic variation explained by all QTLs for specific traits were 42.5%, 36.7%, 49.0%, 53.1%, and 42.6% for seed weight, protein, oil, sucrose, and calcium, respectively. Of the 11 genomic intervals identified in this study, six were associated with more than one seed quality trait. These results suggest that the genetic correlations observed between seed quality traits may be due to a pleiotropic effect of a single QTL or that QTLs controlling different seed quality traits were inherited in clusters as tightly linked loci. / Ph. D.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1944 R5 / Master of Science

Call number: LD2668 .T4 1966 K48 / Master of Science

Call number: LD2668 .T4 1979 L83 / Master of Science

Soybean seeds are known to contain high levels of lipoxygenase activity, especially during early stages of germination. Crude mitochondrial fractions from germinating soybeans also have been shown to exhibit high rates of cyanide-insensitive oxygen uptake. These results show the effects of successive discontinuous PercollR density gradients on mitochondrial fractions from 2 day old soybean seeds as judged by polarographic studies and Ouchterlony double diffusion. Axis mitochondria exhibited totally cyanide-sensitive oxygen uptake after two gradients and cotyledon mitochondria exhibited from none to 11% cyanide-insensitive oxygen uptake after three gradients. Mitochondrial fractions which were assayed for lipoxygenase with double diffusion exhibited positive results with fractions that showed cyanide-insensitive oxygen uptake and negative results with cyanide-sensitive mitochondria. These results suggest that lipoxygenase can loosely associate with the mitochondrial membrane and that gradient centrifugation can purify mitochondria free of both lipoxygenase and cyanide-insensitive oxygen uptake.

by Lee Yuen Chong. / Bibliography: leaves 112-131 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985

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