Master of Science

Examination of use of terminology using "carbohydrates" to describe reserve energy to plants. / Master of Science

Carbohydrates and fats are the main fuel sources for energy production during exercise. Consumption of low glycemic index foods slows digestion and absorption in the small intestine. The slow digestibility of resistant starch containing foods contributes to the slow and sustained release of glucose into the bloodstream, minimizing occurrence of hyperinsulinemia-induced suppression of lipolysis. The objectives of this study were to determine the consumption of resistant starch (RS) by regular exercisers (Blacksburg and San Jose (SJ)); and to analyze the eating and exercise habits of the subjects. Subjects were recruited at gyms in SJ (n=27) and Blacksburg (n=26). Participants kept 3-day food records and completed a questionnaire on eating habits and physical activity. Mean body mass index for the subjects was similar (SJ: 23.06 Kg/m² ± 2.55; Blacksburg: 23.53 Kg/m² ± 3.09). Average exercise time was 12 hours/week, and > 50% engaged in weight training in addition to aerobic type exercise. Percentage contribution of carbohydrates to the total energy intake was significantly higher for SJ males (53.53% ± 8.06%) compared to Blacksburg males (48.39% ± 6.33%; alpha=0.10). Prominent RS food sources in both groups were pasta, potatoes, bananas, and corn. Rice and various legumes were more frequent in the SJ group. It appears that consumption of RS is higher among SJ subjects. Consumption of RS prior to prolonged exercise could cause stable glycemic and insulinemic responses that may help delay the onset of fatigue during exercise. / Master of Science

Alfalfa (Medicago sativa L.) harvest schedules are often interrupted by rainfall, unfavorable environmental conditions for growth, and unfavorable weather for hay curing. Interruptions in alfalfa harvest schedules can delay the final harvest until dates considered critical to winter survival. Harvests made between 20 September and 30 October are considered detrimental to the persistence of alfalfa stands in geographical areas such as western Virginia. The objectives of this study were to determine if a critical period for fall harvest management actually exists in Virginia, if length of the growth period prior to fall harvest (GPPFH) influences plant persistence and succeeding spring yields, and if photosynthesis offsets respiration and allows more flexible fall harvest management than is currently recommended. Final alfalfa harvests were made 10, 20, or 30 September or 10, 20, or 30 October for 2 years in two identical experiments. Alfalfa was managed to achieve 30, 40, 50, or 60 days of growth prior to each fall harvest date. Total nonstructural carbohydrates (TNC) in tap roots and population of surviving plants were determined in December and March. Succeeding spring yields were measured in May. Zero, 45, and 60 percent shade were imposed following four fall harvest dates in a supplemental study to investigate the influence of photosynthesis on TNC levels and plant persistence. In the supplemental study, CO₂ exchange and TNC were measured at 2 week intervals in the fall following four fall harvest dates. Harvests made during the fall period previously considered as critical did not cause over-wintering plant losses. Length of growth period prior to fall harvests was more important than date of fall harvest in making management decisions for fall harvest. Although spring yield generally increased with length of GPPFH, the spring growth appeared healthy; so one might expect a few days of delay prior to the first spring harvest to eliminate any detrimental influence of short length of GPPFH. Succeeding spring yields and TNC levels were generally high for the 50-day GPPFH, and fall harvest yield offset any reductions in spring yield observed in this study. In addition, fall harvests made with a 50-day GPPFH maintained quality and leafiness as opposed to a 60-day GPPFH. Fall regrowth and plant maintenance were not dependent on root TNC accumulation. Photosynthesis offset TNC losses for regrowth and maintenance during the fall. High photosynthetic rates as compared to respiration occurred because temperatures were within the optimum range for photosynthesis of alfalfa during 68% of the daylight hours from September through November. There was no critical period for fall harvest management with the environmental conditions experienced during this study. A 50 or 60-day GPPFH prior to fall harvest was adequate for plant persistence and high succeeding spring yields. / Ph. D.

Lee, Ying. / On t.p. "beta" appears as the Greek letter. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 171-196). / Abstracts in English and Chinese. / Thesis/Assessment Committee --- p.i / Acknowledgement --- p.ii / Abstract --- p.iii / 摘要 --- p.v / List of Tables --- p.vii / List of Figures --- p.x / List of Abbreviations --- p.xvii / Content --- p.xviii / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Probiotics and Prebiotics --- p.1 / Chapter 1.1.1 --- Definitions --- p.1 / Chapter 1.1.2 --- Previous studies --- p.2 / Chapter 1.1.3 --- Properties of enhanced prebiotics --- p.6 / Chapter 1.1.4 --- Synbiotics --- p.7 / Chapter 1.2 --- Colonic fermentation --- p.10 / Chapter 1.2.1 --- Major substrates and metabolites of colonic fermentation --- p.10 / Chapter 1.2.2 --- Health-related effects of Short-Chain Fatty Acids (SCFAs) --- p.12 / Chapter 1.3 --- Bifidogenic effect --- p.14 / Chapter 1.3.1 --- Definition of bifidogenic factor and its health benefits --- p.14 / Chapter 1.3.2 --- Carbohydrate metabolism by related enzymes of bifidobacteria --- p.16 / Chapter 1.3.3 --- Previous studies on bifidogenic effects of carbohydrates --- p.18 / Chapter 1.4 --- Barley β-glucan --- p.18 / Chapter 1.4.1 --- Cereal fibres as prebiotics --- p.18 / Chapter 1.4.2 --- Chemical and physical properties and related health impacts of barley β-glucan --- p.19 / Chapter 1.4.3 --- Impacts on intestinal microecology --- p.21 / Chapter 1.4.4 --- Previous studies on bifidogenic effects of barley β-glucan --- p.21 / Chapter 1.5 --- Methodology for evaluating prebiotic and bifidogenic effect --- p.22 / Chapter 1.5.1 --- In vivo animal models --- p.23 / Chapter 1.5.2 --- Human clinical study --- p.23 / Chapter 1.5.3 --- In vitro fermentation study --- p.24 / Chapter 1.5.3.1 --- Pure culture --- p.24 / Chapter 1.5.3.2 --- Mixed culture bacterial fermenters --- p.25 / Chapter 1.5.3.3 --- Continuous culture systems as in vitro gut models --- p.25 / Chapter 1.5.4 --- Advanced molecular techniques in quantifying intestinal bacteria --- p.26 / Chapter 1.6 --- Factors affecting bifidogenic effect --- p.30 / Chapter 1.6.1 --- Molecular weight --- p.30 / Chapter 1.6.2 --- Species difference --- p.31 / Chapter 1.7 --- Enzymatic activities involved in fermentation of β-glucan --- p.32 / Chapter 1.7.1 --- "Endo-1,3-1,4-(3-glucanase (Lichenase)" --- p.32 / Chapter 1.7.2 --- "Endo-l,4-β-Glucanase (Cellulase)" --- p.33 / Chapter 1.7.3 --- Enzymatic assays --- p.33 / Chapter 1.8 --- Project objectives --- p.36 / Chapter Chapter 2. --- Materials and Methods --- p.37 / Chapter 2.1 --- Materials --- p.37 / Chapter 2.1.1 --- "Trehalose, chitin and lactulose" --- p.37 / Chapter 2.1.2 --- Barley β-glucan --- p.37 / Chapter 2.1.3 --- Pure Bifidobacterium species of human origin --- p.39 / Chapter 2.2 --- Static batch culture fermentation using fecal inoculums --- p.39 / Chapter 2.2.1 --- Substrate preparation --- p.39 / Chapter 2.2.2 --- Human fecal inoculum preparation --- p.41 / Chapter 2.2.3 --- Inoculation of human fecal inoculums --- p.41 / Chapter 2.3 --- Static batch culture fermentation using pure culture of bifidobacteria --- p.42 / Chapter 2.3.1 --- Substrate preparation --- p.42 / Chapter 2.3.2 --- Cultivation of pure bifidobacterium cultures --- p.43 / Chapter 2.3.3 --- Inoculation of bifidobacterium culture --- p.44 / Chapter 2.3.4 --- Growth curve of Bifidobacterium species --- p.44 / Chapter 2.4 --- Dry matter and organic matter disappearance in batch fermentation --- p.47 / Chapter 2.5 --- Gas chromatographic (GC) determination of short-chain fatty acids (SCFAs) --- p.48 / Chapter 2.6 --- MTT assay --- p.51 / Chapter 2.7 --- Microbial identification and enumeration --- p.53 / Chapter 2.7.1 --- Fluorescent in situ hybridization --- p.53 / Chapter 2.7.1.1 --- Oligonucleotide probes for fluorescent in situ hybridization --- p.53 / Chapter 2.7.1.2 --- Cell fixation --- p.54 / Chapter 2.7.1.3 --- In situ hybridization --- p.55 / Chapter 2.7.1.4 --- Automated image analysis --- p.55 / Chapter 2.7.1.5 --- Quantification of bacteria --- p.57 / Chapter 2.7.2 --- Optical Density (OD) measurement --- p.58 / Chapter 2.7.3 --- Direct microscopic count --- p.59 / Chapter 2.8 --- Enzyme assays --- p.60 / Chapter 2.8.1 --- Enzyme extraction --- p.60 / Chapter 2.8.2 --- "Endo-1, 3:1, 4-β-glucanase (Lichenase)" --- p.61 / Chapter 2.8.2.1 --- Principle --- p.61 / Chapter 2.8.2.2 --- Preparation of substrate and assay solutions --- p.63 / Chapter 2.8.2.3 --- Enzyme assay procedures --- p.64 / Chapter 2.8.3 --- "Endo-l,4-β-Glucanase (Cellulase)" --- p.65 / Chapter 2.8.3.1 --- Principle --- p.65 / Chapter 2.8.3.2 --- Dissolution of substrate and preparation of assay solutions --- p.65 / Chapter 2.8.3.3 --- Enzyme assay procedures --- p.66 / Chapter 2.8.4 --- API@ ZYM kit --- p.67 / Chapter 2.8.4.1 --- Principle --- p.67 / Chapter 2.8.4.2 --- Specimen preparation --- p.68 / Chapter 2.8.4.3 --- "Preparation, inoculation and reading of the strips" --- p.70 / Chapter 2.9 --- Statistical analysis --- p.71 / Chapter Chapter 3 --- Results and Discussions --- p.72 / Chapter 3.1 --- Growth curves of Bifidobacterium species --- p.72 / Chapter 3.2 --- Batch in vitro fermentation using human fecal inoculum --- p.79 / Chapter 3.2.1 --- Dry matter and organic matter disappearance --- p.79 / Chapter 3.2.2 --- Colonic bacterial profile evaluated by FISH with CellC software --- p.81 / Chapter 3.2.2.1 --- Total colonic bacteria --- p.81 / Chapter 3.2.2.2 --- Bifidobacterial growth --- p.82 / Chapter 3.2.3 --- SCFA production --- p.86 / Chapter 3.2.3.1 --- Acetate --- p.88 / Chapter 3.2.3.2 --- Propionate --- p.89 / Chapter 3.2.3.3 --- Butyrate --- p.89 / Chapter 3.2.3.4 --- Total SCFA production --- p.90 / Chapter 3.2.3.5 --- Molar ratio of SCFAs --- p.92 / Chapter 3.3 --- In vitro fermentation of barley β-glucans with different molecular weight using pure culture of Bifidobacterium species --- p.95 / Chapter 3.3.1 --- Dry matter and organic matter disappearance --- p.96 / Chapter 3.3.2 --- Evaluation of bifidobacterial growth by optical density (OD) --- p.100 / Chapter 3.3.3 --- Time course study of SCFAs production --- p.109 / Chapter 3.3.3.1 --- "Total and individual SCFAs (Acetate, Propionate and Butyrate) production" --- p.109 / Chapter 3.3.4 --- Correlation between various parameters related to fermentation --- p.124 / Chapter 3.4 --- Enzymatic activities in 2 selected Bifidobacterium species during fermentation --- p.125 / Chapter 3.4.1 --- Dry matter and organic matter disappearance --- p.126 / Chapter 3.4.2 --- Bifidobacterial growth evaluated by direct microscopic count --- p.128 / Chapter 3.4.3 --- Time course study of SCFAs production --- p.131 / Chapter 3.4.3.1 --- "Total and individual SCFAs production (Acetate, Propionate and Butyrate)" --- p.131 / Chapter 3.4.3.2 --- MTT assay --- p.137 / Chapter 3.4.3.2.1 --- Effect of metabolites in the fermentation medium on the proliferation ofSW620 --- p.137 / Chapter 3.4.3.2.2 --- Effect of metabolites in the fermentation medium on the proliferation of Caco-2 --- p.145 / Chapter 3.4.4 --- Enzyme assays using commercial kits --- p.153 / Chapter 3.4.4.1 --- API @ZYM assay --- p.153 / Chapter 3.4.4.2 --- Efficiency of intra-cellular enzyme extraction using labiase --- p.156 / Chapter 3.4.5 --- Time course enzyme assays --- p.157 / Chapter 3.4.5.1 --- Lichenase activity assay --- p.157 / Chapter 3.4.5.2 --- Cellulase activity assay --- p.160 / Chapter Chapter 4. --- Conclusions and Future work --- p.168 / References --- p.171

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Sous un climat tropical humide, l'augmentation de la température nocturne a été associée à une diminution du rendement chez le riz. Une des hypothèses sous-tendant cette diminution est l'augmentation du taux de respiration nocturne (Rn) diminuant les ressources carbonées disponibles pour la croissance de la plante. La respiration mitochondriale est communément divisée en deux composantes fonctionnelles :- la respiration de maintenance (Rm), qui est associée à toutes les réactions biochimiques requises pour entretenir la biomasse existante. Le taux de Rm doublerait suite à une augmentation de la température ambiante de 10°C (Q10 = 2) ;- la respiration de croissance (Rg), qui est associée à tous les processus impliqués dans la création de biomasse. Cette composante de la respiration est principalement dépendante de la disponibilité en carbohydrates dans la plante, et donc de la photosynthèse.Ce travail de thèse a pour objectifs de (1) déterminer l'effet instantané (sans acclimatation) et sur le long terme (acclimatation) de l'augmentation de la température nocturne, proche de celle prédite par les scénarios climatiques, sur la respiration et la production de biomasse et de grains, (2) évaluer le coût de Rn en terme de biomasse à l'échelle de la plante entière, (3) estimer la respiration de maintenance (Rm) et sa réponse à l'augmentation de la température, et (4) évaluer l'effet de la valeur Q10 sur la modélisation de la production en biomasse. Pour atteindre ces objectifs, trois expérimentations (dont une inexploitable) ont été conduites en serre, deux en chambres de culture et une au champ, à Montpellier (France) et à la station expérimentale de l'IRRI (International Rice Research Institute, Philippines). L'augmentation modérée de la température nocturne de 1.9°C au champ et 3.5°C en chambre de culture de l'initiation paniculaire à maturité, et de 3.8 à 5.4°C en serre du repiquage à maturité, a entraîné l'augmentation significative de Rn (+13 à +35%). Dans le même temps, cette augmentation n'a pas eu d'effet significatif sur la production de biomasse et de grains des écotypes indica et aus, mais la production en grains de l'écotype japonica a été significativement plus faible. Le coût en biomasse de la respiration, en conditions de température nocturne plus élevée, a augmenté légèrement mais n'a pas été associé à une variation significative de la production de biomasse. L'augmentation de la température nocturne sur le long terme (acclimatation) a eu un impact plus faible sur Rn (facteur de 1.14 à 1.67 entre 21 et 31°C) que l'augmentation instantanée (sans acclimatation) (facteur 2.4 entre 21 et 31°C). Le coût quotidien en biomasse de Rm, a été de 0.3 à 1.2% (feuilles complètement développées) et de 1.5 à 2.5% (plantules entières). La Rm a augmenté d'un facteur 1.49 entre 21 et 31°C et représentait environ 33% de la respiration nocturne. Ce facteur est plus faible que l'hypothèse du Q10 = 2 qui surestime les effets de l'augmentation des températures sur Rm.Le modèle d'analyse de sensibilité a montré que la valeur du coefficient Q10 a un rôle significatif dans la prédiction de la production de biomasse dans les modèles de culture. Le rendement simulé diminue de 9% (Q10 = 2) et de 5% (Q10 = 1.5) lorsque la température moyenne journalière augmente de 2°C. Ainsi, prendre en compte l'acclimatation dans la réponse des plantes à l'augmentation des températures est important pour augmenter la précision des modèles. L'augmentation de la précision des modèles passera aussi par l'analyse des variations de la respiration en conditions naturelles. / In tropical climate, increasing night temperature was reported to be associated with a decline in grain yield in rice. This can be partly due to an increase in night respiration rate (Rn) which causes a depletion of carbohydrate supply available for plant growth. Mitochondrial respiration is commonly divided in two functional components; - Maintenance respiration (Rm) which is associated with all biochemical reactions required to maintain existing biomass. The rate of this respiration component would double when ambient temperature increase by 10°C (Q10 = 2). - Growth respiration which is associated with all processes involved in establishment of new biomass. This respiration component is mainly driven by carbohydrate supply and thus, by the photosynthesis rate. The present work aims to (1) determine the effects of short-term (without acclimation) and long-term (with acclimation) increase in night temperature similar to that projected by future climate scenarios on vegetative biomass production and grain yield; (2) evaluate, in terms of loss of biomass, the cost of Rn at plant scale; (3) estimate the maintenance respiration rate (Rm) and its response to temperature; and (4) evaluate the impact of Q10 value on biomass production. To achieve these objectives, three experiments (one unexploitable) were conducted in greenhouses, two in growth chambers and one in the field, at Montpellier (France) or at the experimental station of IRRI (International Rice Research Institute). The moderate increase in night temperature from panicle initiation to maturity in the field by 1.9°C and in growth chambers by 3.5°C, and form transplanting to maturity in greenhouse experiments by 3.8 to 5.4°C, did affect significantly Rn that increased by 13 to 35%. In the same time, it did not affect significantly biomass production and grain yield for indica and aus cultivars, whereas grain production decline was observed for japonica. Calculated biomass losses due to increased Rn under increased night temperature were important but were not associated with a change in biomass production or grain yield. Effect of long-term exposure to increased night temperature (acclimation) was smaller (factor 1.14 to 1.67 between 21 to 31°C) than that of short-term exposure (without acclimation) (factor 2.4 between 21 to 31°C). In this work, 0.3 to 1.2% (expanded leaves) and 1.5 to 2.5% (whole seedlings) of existing dry biomass was lost daily to Rm. The Rn was composed by about 33% of Rm, which increased by factor 1.49 between 21 and 31°C. This is below the common assumption of Q10 = 2 that thus overestimates the effect of increasing night temperature on Rm.A model sensitivity analysis showed that the Q10 value is important in the prediction of biomass production in crop models. Yield is expected to decline by 9% (Q10 = 2 assumption) and by 5% (Q10 = 1.5 assumption) with increasing mean daily temperature by 2°C. Thus, taking into account the acclimation response to temperature change is important for models accuracy. Making crop models more accurate requires more knowledge thermal effect on respiration in the field.

Master of Science / Department of Animal Sciences and Industry / Teresa L. Douthit / Abruptly increasing concentrate in the ration of horses results in altered cecal dynamics which can culminate in digestive distress. Nine Quarter horses previously fitted with cecal cannulae were utilized for 3 consecutive 22-d experiments, each separated by 2 d of rest. During Exp. 1 and 2 horses were acclimated to the same ration for the initial 21 d of each period, followed by a concentrate challenge on d 22. The acclimation ration consisted of a morning meal of 0.5% BW concentrate (Omolene 200, Purina Animal Nutrition, LLC, Gray Summit, MO) fed with 1.5% BW prairie grass hay divided evenly between a morning and evening meal. On d 22 of Exp. 1, horses were fed a morning meal consisting solely of 1.0% BW concentrate while 1.25% BW concentrate was fed on d 22 of Exp. 2. Cecal samples were obtained through cecal cannulae from d 19 to 22 of each experiment every 4 h for h 24 following the morning meal each day. Cecal pH during Exp. 1 was recorded and decreased at h 12 following the concentrate meal on d 22 in comparison to cecal pH at h 12 on d 19 to 21 (P = 0.009). During Exp. 2 cecal pH increased at h 4 (P = 0.02) and decreased at h 12 and 20 (P < 0.0001) following this oncentrate challenge compared to cecal pH recorded at the same time points during the acclimation period. Experiment 3 differed from that of Exp. 2 only in the respect that during the acclimation period horses were fed, in addition to the acclimation ration, either a proprietary supplement (n = 5) or a placebo (n = 5). Cecal samples from d 19 to 22 were analyzed for pH, concentration of lactate, and concentration of VFA. Horses consuming the supplement had increased cecal pH at h 4 (P = 0.009), concurrently decreased cecal lactate (P = 0.02), increased ratio of (acetate+butyrate)/propionate at h 8 and 16 (P ≤ 0.006), and decreased VFA concentration at h 24 (P ≤ 0.05) compared to horses in the control group following the concentrate challenge.

Typescript (photocopy). / Digitized by Kansas Correctional Industries