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In order to identify plant genes involved in the Rhizobium/legume root nodule symbiosis, host gene expression during soybean nodule development was studied. The hybridization of complementary DNA (cDNA) probes with homologous and heterologous polyadenylated polysomal RNAs showed that most of the 20,000-25,000 RNA sequences expressed were common to uninfected root and nodule tissues. There was a marked increase in the relative concentration of leghaemoglobin and moderately abundant nodule sequences following infection by Rhizobium. A nodule-specific cDNA probe (NS-cDNA), prepared by eliminating common root sequences by cascade hydroxylapatite chromatography, was used to characterize a small population of nodule-specific sequences. Hybridization of NS-cDNA to DNA from soybean embryos and not to Rhizobium demonstrated that these sequences are encoded by the host genome. Hybridization with nuclear RNA from uninfected tissues showed that the primary mode of regulation of these sequences is at the level of transcription. Expression of these small nodule-specific-mRNAs is differentially modulated by ineffective strains of Rhizobium. The relative concentration of nodule-specific and common moderately abundant sequences increased to varying extents, in parallel with leghaemoglobin, reaching a peak when nitrogen fixation commences. These data suggest that host gene expression is coordinately regulated during early nodule development. Indoleacetic acid appeared to modulate the expression of common moderately abundance sequences, but had no detectable effect upon leghaemoglobin or nodule-specific sequences. Preliminary characterization of 26 cDNA clones indicated that, in addition to leghaemoglobin and other positively regulated sequences, there were two clones whose mRNA concentration decreased during nodule development.

Thesis (DBA(Doctorate of Business Administration))--University of South Australia, 2003.

Doctor of Philosophy(PhD) / Soybeans contain around 40% of high quality protein and 20 % of oil. Soy protein has long been used as ingredients for its emulsification and texturizing properties in a variety of foods, soymilk and tofu being the most popular. Soymilk is essentially a water extract of soybeans and there are many variations on the basic soymilk processing steps. Tofu, or bean curd, is made by coagulating soy milk, and then pressing the resulting curds into blocks. This thesis was mainly devoted to thermal denaturation and coagulation of soy proteins and targeted several selected important factors as they relate to the functional properties. The effects of different chemical coagulants as well as proteases on yield and quality of tofu from soybeans were studied. Eight tested chemical coagulants were able to coagulate the soymilk and the results showed that the concentration of soymilk and type of coagulant had a great influence on the properties of the tofu gel. The results also confirmed that the use of a suitable concentration of the quick-acting coagulants is more critical than that of the slow-acting coagulants in tofu making. In general, the extent of soymilk gelation is not determined by a single characteristic but rather results from a combination of factors. The gelation ability of various most common commercially available proteases to coagulate non-defatted soymilk was surveyed and the thermal stabilities of selected protease systems were compared. The difference in the temperature where the enzyme shows its highest activity seemed to be the most significant indicator when choosing a suitable enzyme for a certain industrial application. The three most effective and versatile soymilk coagulants were identified. The presence of small amounts of ficin in the system increased the protein recovery when calcium chloride was used as a coagulant. The most commonly used techniques of analysis of degree of hydrolysis (TNBS, OPA and pH-stat) of soy protein were compared. It was concluded that the pH-stat technique was useful for evaluating the progress of an enzyme-catalyzed protein hydrolysis process on an industrial scale while the OPA method seemed to be the most suitable method to be used for determining DH during the proteolysis of soymilk in laboratory conditions. The roles of soybean proteins, protein fractions and subunits to differences in gelling properties of different soybean varieties were examined. The variability and the interrelationship between soybean seed traits were established and the seed characteristics related to soymilk yield and tofu quality were identified. The results suggested that it is useful to predict the quality of tofu from a combination of characteristics of the soybean seed. It was concluded that large differences exist in soybean seed characteristics and their contributions towards the properties of the final product and implications were made towards the relative importance of individual soybean seed traits to the functional and textural properties of soy products. The SDS gel capillary electrophoresis was applied to characterize soybean storage proteins. The lab-on-a-chip technology was compared with capillary electrophoresis and these two methods were used to quantify the relative amount of 7S and 11S fractions in various soybean cultivars. It was concluded that both lab-on-a-chip instrument and a traditional CGE were adequate for analysis of soy-based products. Both systems were able to reliably quantify the relative amount of protein fractions in samples and thus demonstrate their different genetic origin. The great advantage of the lab-on-a-chip technology is its time-efficiency while the traditional CGE is a preferred instrument for method development. The usefulness of the chemometrical analysis of electrophoretic profiles as a method for objective evaluation, data reduction and interpretation was shown. The possibility of improvement of the protein extraction from soybeans in order to provide a basis for the optimization of soymilk production was studied. The enzyme-assisted extraction using the hydrolytic enzyme treatment to disrupt the soybean cell wall components was expected to improve the protein extraction yield. The results confirmed that the right selection of operational variables led to an increased yield of soymilk as well as its protein concentration. It was also shown that the addition of selected enzyme preparations into the soymilk process design resulted in an increased extraction yield of proteins from seeds into soymilk. The protein quality did not deteriorate during the enzyme-assisted extraction process and a small amount of microbial transglutaminase added together with a coagulant produced tofu with a significantly increased yield while maintaing satisfactory textural properties.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 2, 2008) Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 169-171). Also available via the Internet.

Thesis (Ph.D.). / Written for the Dept. of Food Science and Agricultural Chemistry. Title from title page of PDF (viewed 2008/05/12). Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 98-100). Also available via the Internet.

Thesis (M.S.)--Northwest Missouri State University, 2008. / The full text of the thesis is included in the pdf file. Title from title screen of full text.pdf file (viewed on July 25, 2008) Includes bibliographical references.