No description available.

Bacteroids of B. japonicum from nodules of soybean roots were isolated using differential centrifugation (the standard bench method) and density gradient centrifugation methods (either sucrose- or Percoll-) under anaerobic conditions in which N2 fixation was preserved. The relationships between N2 fixation and respiration, O2 supply, O2 demand, substrate (mainly malate) transport and metabolism in bacteroids were investigated using the flow chamber system. In related experiments, the primary products of N2 fixation which leave the bacteroids were investigated using a 15N-labelling technique in a closed shaken system and other biochemical methods.¶ In the flow chamber experiments, the rates at which O2 was supplied to bacteroids in the chamber were varied by (a) changing the flow rate of reaction medium through the chamber; (b) by changing the [O2 free] in the inflowing reaction medium by using either 3-5% (v/v) or 100% air in the gas mixture above the stirred reaction medium in two reservoir flasks; (c) by successively withdrawing bacteroids from the chamber, thus increasing the supply of O2 per bacteroid to those remaining in the chamber. The results showed that the rate of O2 supply regulates respiratory demand for O2 by bacteroids rather than the O2 concentration present in the reaction system. Respiration is always coupled to N2 fixation. ¶ Uptake of malate by bacteroids withdrawn from the flow chamber was measured under microaerobic conditions. Malate uptake by these N2-fixing bacteroids was lower than that by bacteroids isolated under aerobic conditions, which eliminate N2 fixation of bacteroids, but is closely correlated with bacteroid respiration rates. When respiration was increased by an increase in O2 supply, malate uptake by bacteroids was also increased. This suggested that transport of malate through the bacteroid membrane is also regulated by O2 supply, but indirectly. Higher uptake by bacteroids under aerobic conditions was observed because respiration was enhanced by the high availability of O2, but the fast uptake of malate by bacteroids driven by the abnormal respiration rates may not reflect the reality of malate demand in vivo by bacteroids when N2 fixation by bacteroids is fully coupled. ¶ The results of 15N labelling experiments and other biochemical assays once again demonstrated that ammonia is the principal significant 15N labelled product of N2 fixation accumulated during 30 min in shaken assays with 0.008-0.01 atm O2. Alanine although sometimes found in low concentrations in the flow chamber reactions, was not labelled with 15N in shaken closed system experiments. No evidence could be obtained from the other biochemical assays, either. Therefore, it is concluded that these and earlier results were not due to contamination with host cytosolic enzymes as suggested by Waters et al. (Proc. Natl. Aca. Sci. 95, 1998, pp 12038-12042). ¶ Malate transported into bacteroids is oxidized in a modified TCA cycle present in bacteroids. The results of flow chamber experiments with a sucA mutant (lacking a-ketoglutarate dehydrogenase) showed that respiratory demand for O2 by the mutant bacteroids is regulated by O2 supply in the same way as the wild-type. Despite differences in other symbiotic properties, rates of nitrogen fixation by the mutant bacteroids, based on the bacteroid dry weight, appeared to be the same as in the wild-type. Also N2 fixation was closely coupled with respiration in the same manner in both mutant bacteroids and wild type bacteroids. These results and other supporting data, strongly support the conclusion that there is an alternative pathway of the TCA cycle in bacteroids, which enables the missing step in the mutant to be by-passed with sufficient activity to support metabolism of transported malate.

Bibliography: leaves 189-210 / xxxiv, 210 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1987

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / 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 (February 27, 2007) Vita. Includes bibliographical references.

A Low-fat Diet Containing Heated Soybean Oil Promotes Hyperglycemia in C57BL/6J Mice Introduction: The metabolic effects of consuming mildly oxidized lipids as compared to highly oxidized lipids are not well documented. Consumption of highly oxidized polyunsaturated fatty acids, even in a low-fat diet, may be a threat to one’s health. Previous studies in our lab have shown that mice consuming soybean oil heated for 3 hours, compared to unheated, gain less body weight, but more fat pad mass, and 3T3-L1 adipocytes treated with soybean oil heated for ≥ 6 hours have abrogated triglyceride accumulation. Another study showed that rats fed highly oxidized oil (heated > 24 hrs), as compared to fresh soybean oil and fish oil, had lower fat pad mass and weight gain but developed glucose intolerance. This suggested that the extent of lipid oxidation determined the subsequent metabolic risk. Objective: Our aim, in the current study, is to investigate if a low-fat diet with soybean oil heated for increasing time points (3h, 6h and 9h) alter fat mass and glucose tolerance. Methods: Six week old, male, C57BL/6J mice were randomly divided into six groups (n=8/group). Three groups were fed a low fat diet with soybean oil heated for 3 (3hr-HO), 6 (6hr-HO), or 9 (9hr-HO) hours for 16 weeks. Another three groups were pair-fed to each of the 3hr-HO, 6hr-HO and 9hr-HO groups with a low-fat diet containing unheated oil (PF-UHO). Food consumption was recorded every 3-4 days, and body weights were recorded weekly. Soy oil in the diets was analyzed for products of oxidation. At 16 weeks, blood glucose levels were measured after a 6 hour fast; fat pad and liver weights were recorded, and blood was collected by cardiac puncture for serum insulin analysis. Results: Final weight gain was not significantly different between all HO groups as a percent of their respective PF groups (p >0.05). The feeding efficiency for 3hr, 6hr, and 9hr-HO groups as a percent of PF was 92.75, 113.02, and 111.28, respectively. Mean weights of all fat pads for HO groups decreased with heating time as a percent of PF, although these differences were not statistically significant. Blood glucose was lowest in the 3hr-HO group and significantly increased from 3hr-HO group to 6hr-HO group (p=0.021) as a percent of PF. Serum insulin levels decreased for the HO groups as heating time increased, although these differences were not statistically significant. Conclusion: Consuming a diet with increasing amounts of oxidized lipids decreased fat pad mass and insulin levels, while increasing fasting glucose levels. This paradoxical relationship between increased glucose in the presence of decreased insulin in c57BL/6J mice could be due to either reduced insulin secretion or increased insulin resistance. Further research in our lab will aim to analyze triglyceride accumulation in the liver and muscle cells of these mice to determine if oxidized lipids promote ectopic fat deposition.

No description available.

Two experiments were conducted to study the effects of partially substituting fishmeal with 4 soybean products and mineral supplemental levels in diet of juvenile cobia Racycentron canadum. Experiment ¢¹studied the effects of partially substituting fishmeal with 4 soybean products in diet of juvenile cobia. Experiment ¢º investigated the effects of mineral supplement levels in the growth and body retention of zinc and phosphorus when high percentage of fishmeal in the diet was replaced by hexaned-extracted soybean meal or fermented soybean meal. In Experiment ¢¹, cobia juveniles with an initial weight of 58¡Ó1 g were fed eight experimental diets and a fish meal-based basal diet. The experimental diets were of a 2 (Soybean replacement level: 20 and 40 % of fishmeal protein) ¡Ñ 4 (soybean products) experimental design. The 4 soybean products evaluated were solvent-extracted soybean meal (SES), defatted fermented soybean meal (DFS), soybean meal reduced antinutritional factor (ROS) and soy protein concentrate (SPC). The results of the 8-week feeding trail showed that the growth, FCR, PER and NPU of the fish fed with the 40% ROS diet were significantly worse than these of the other groups. Apparent digestibility (%) of dry matter (ADMD), protein (APD) and lipid (ALD) of all diets were not significantly different. In experiment ¢º, eight experiment diets were tested. The first group was a 2¡Ñ3 factorial design, in which SES replacement levels were 40 and 50%, and mineral supplemental levels were 0.5¡Ñ, 1¡Ñ and 2¡Ñ of the regular supplemental level. The second group tested 50% replacement by FS and mineral supplemental level of 0.5¡Ñ and 1¡Ñ the regular supplemental level. The results of the 8-week feeding trail using the juvenile cobia with an initial weight of 72.3¡Ó0.52 g showed that growth of the fish fed with fermented soybean (FS) diets was significantly inferior to that fed with SES diets at 50% replacement level, especially mineral supplemental levels were 1x or less. The fish fed 2 FS diets were not significantly different on feed conversion ratio, net protein utilization and growth. Protein efficiency ratio of the fish fed with the FS diets was only significantly inferior to that fed 40% 1¡Ñ SES diet. Body and vertebrate zinc concentrations of the cobia that fed FS diets were higher than the SES diet groups. Moreover, the fish fed with SES diets at 40% replacement level were higher than that fed at 50% replacement level. At a same mineral supplemental level, phosphorus concentrations in body of the fish fed with FS diets were higher than that fed SES diet. Phosphorus and ash concentrations in vertebrate of the fish fed with all diets were not significantly different. When replacement level was increased from 20 to 40%, the fish that fed with the SES and DFS diets had better growth and condition factor . Fermentation of soybean increased availability of trace minerals such as zinc. Addition of mineral supplemental 2x levels in diet of juvenile cobia apparent to have negative growth effects. Moreover, 0.5x and 1x levels have the same growth promoting effect. The results suggest that reduction from the regular mineral mixture up to 50 % still support the mineral requirements of the cobia.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 222-247). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 222-247). Also available on the Internet.

Thesis (M. Tech. Agriculture, Tshwane University of Technology, 2011. / To increase local growth linkages of smallholder broiler enterprises in rural areas a single-phase, on-farm processed, mash diet, consisting of boiled and ground full-fat soya beans and ground yellow maize grain fortified with lysine, methionine and selected mineral nutrients was first developed and then tested. Financial analysis showed that net operating expenses of broiler enterprises that used the experimental diet were higher than those of similar enterprises using the control diet, but differences in net operating income were only significant in one of the two runs of the experiment. The main economic benefit of using the experimental diet was the added value to the local economy, which increased from 20 % of the retail value of broiler chickens in the case of enterprises using the control diet to 70 % when using the experimental diet.