Call number: LD2668 .T4 1985 A32 / Master of Science

Call number: LD2668 .T4 1985 C84 / Master of Science

Call number: LD2668 .T4 1985 X56 / Master of Science

Rhodococcus rhodochrous DAP 96253, a well-known industrial bacterium, had various 1-hexene monooxygenase (1-HMO) activities when grown on YEMEA plates supplemented with eight different carbohydrates. Besides, 1-HMO exhibited different storage temperature preferences. Lactose could induce the highest 1-HMO activity in R. rhodochrous DAP 96253 while the cells showed the lowest 1-HMO activity when trehalose was the supplement. The 1-HMO activity of R. rhodochrous DAP 96253 was not maintained when stored at 37°C as well as at 4°C and 25°C. Trehalose-induced 1-HMO activity of R. rhodochrous DAP 96253 was more stable from Day 0 to Day 21 at all these three temperatures, compared with the other seven carbohydrates. Immobilization of enzymes can maintain enzyme activity longer, offer easier enzyme storage conditions and make some enzymes reusable, much research has been done in this area. In this study, R. rhodochrous DAP 96253, grown on YEMEA plates supplemented by glucose and urea, was investigated using whole bananas as the inducer of 1-HMO activity and different immobilization methods to maintain this enzyme activity. It was shown that calcium-alginate polyvinyl alcohol (PVA) beads could maintain 1-HMO activity of R. rhodochrous DAP 96253 more stable than calcium-alginate beads. Whole bananas exhibited very obvious effects of inducing 1-HMO activity of R. rhodochrous DAP 96253. A number of recent studies have clearly demonstrated that induced cells of R. rhodochrous DAP 96253 can prolong the shelf-life of post-harvested fruits. With USDA estimates of 40% of all harvested produce in the US not being consumed because of loss of quality, the ability to extend the period of ripeness of produce has great potential to improve the quality of nutrition. Modification or degradation of those signals (primary and secondary) associated with ripening in fruit or the perception of those signals represents a potential mode of action for delayed ripening by induced cells of R. rhodochrous DAP 96253. Ethylene and cyanide are the two primary signals in ripening. In this study, the role of 1-HMO from induced cells was investigated by time-course experiments focusing on 1-HMO activity and stability. In addition, fruit volatile organic compounds (VOCs) were detected and compared by GC-FID and GC/MS over the course of fruit ripening. The results show a correlation between 1-HMO activity and stability in delayed fruit ripening. It was further demonstrated that the presence of secondary signal fruit VOCs enhanced 1-HMO activity. Aromatic profiles of treated fruits, by GC-FID and GC/MS, show a consistent picture of VOCs associated with earlier fruit ripening stages.

The controversial condition of carbohydrate craving is believed by some researchers to be a defect in the regulation of food intake by an individual. This defect is believed to be responsible for the inability of some persons to control their food intake and therefore their weight. Research was conducted to test the hypothesis that, given a group of carbohydrate cravers and a group of noncravers, the cravers will experience a greater plasma insulin response (concentration and area under the curve) than will the noncravers, and that, because of this higher response, the cravers will experience equal or lower plasma glucose levels during a carbohydrate load. A second hypothesis was that, because of cephalic insulin response due to sensory stimuli, cookies would elicit a greater plasma insulin response than would a glucose solution. This higher plasma insulin response may in part explain the uncontrollable snacking that some individuals experience. The purpose of this research was to attempt to identify a biochemical distinction between persons who crave carbohydrates and persons who do not crave carbohydrates. Eleven overweight female subjects, age 30 to 40, were recruited and divided into two groups, five carbohydrate cravers and six noncravers, based on scores received on a questionnaire that was devised for this study to attempt to distinguish between the groups. A Restrained Eating questionnaire was also administered to the subjects. Both groups had similar, but high, restrained eating scores, indicating that all of the subjects were probably restrained eaters. The eating restraint, as supported by the reported frequency of dieting among the subjects, may well have influenced the subjects' responses to the carbohydrate craving questionnaire. Utilizing these two groups of subjects, two tests were administered. The oral glucose tolerance test was administered, utilizing 75 g of carbohydrate each in the forms of glucose solution and cookies, which were administered in a random order. The tests were administered during the premenstrual phase of the subjects' menstrual cycles, 0-10 days prior to the onset of menstruation. Blood was drawn and assayed for plasma glucose and insulin. The research showed that the cravers experienced a significantly greater plasma insulin concentration and area under the curve than the noncravers, particularly at the 30, 60 and 120 minute time points with the glucose treatment. For the glucose treatment, the cravers experienced plasma insulin concentrations that were 32% to 50% greater than those of the noncravers in the early portion of the test. This supports the hypothesis which states that cravers will experience a greater plasma insulin response to a carbohydrate load than will noncravers. This elevated plasma insulin level may be responsible for the carbohydrate cravings that the individuals experience. There was no significant difference in plasma glucose levels at any time point in either of the tests as compared between the cravers and noncravers, thus supporting the expectation that these levels would be similar between the groups. The hypothesis that cookies would elicit a greater plasma insulin response than would a glucose solution was not supported. Any cephalic insulin response which may have resulted from the sight and smell of the cookies, while not specifically measured, was not strong enough to override the physiological factors that control insulin release. Therefore, the glucose solution elicited a significantly greater plasma insulin concentration than did the cookies in the cravers during the first two hours of the tests, and a significantly greater area under the curve for the cravers at 60 minutes and both groups at 120 minutes. However, the cookies did have an effect on insulin release at the fasting point, causing elevated (x = 79%) plasma insulin levels in three of five subjects who were waiting while others were eating the cookies, as compared with these subjects' fasting insulin levels when they were not exposed to the cookies prior to their glucose test. Another finding was a difference between the groups in fasting plasma insulin concentrations over the 10 day premenstrual portion of their menstrual cycles. The noncravers experienced fasting plasma insulin concentrations that decreased as the onset of menstruation was approached, which would parallel the decrease in progesterone levels. However, the cravers experienced first a decrease in fasting plasma insulin levels to day 3 premenstrual, and then an increase to the level of that found 8-10 day premenstrual. This pattern is contrary to what would be expected as progesterone levels drop, and suggests an altered pattern of progesterone levels in the cravers, although progesterone was not measured in this study. To summarize, in a group of overweight women, carbohydrate cravers and non cravers, the cravers experienced a greater plasma insulin response than did the noncravers for the glucose treatment but not for the cookie treatment, and there was no significant difference between the groups for plasma glucose concentration for either treatment. / Graduation date: 1991

The importance of muscle glycogen as a fuel source during exercise has been well documented. Maintaining a high glycogen level before and during activity is a major determinant of performance. Elevation of glycogen levels during recovery from both aerobic and anaerobic bouts of exercise is critical. The purpose of this investigation was to determine the effect of a solid carbohydrate feeding on glycogen resynthesis following aerobic and anaerobic exercise. Eight male cyclists were recruited for this investigation. One hour ride trial, 70 % VO2max followed with feeding (HRY), one sprint trial followed with feeding (SPY), and one sprint trial followed with no feeding (SPN) were randomly performed and separated by ten days. Feeding trials consisted of a solid CHO source (1g CHO per kg bw per hr) fed for four hours of recovery following one hour of passive recovery with no food. Muscle biopsies were obtained immediate post and at six hours of recovery. Bloods were collected at 1, 4, and 30 minutes of recovery for lactate determination. Muscle specimens were analyzed for glycogen and lactate. Muscle glycogen (mmol • kg protein') levels post exercise for HRY, SPN, and SPY trial were 336.9±48.1, 481.0±47.0, and 417.5±26.4, respectively with HRY significantly lower than SPN. The increase in muscle glycogen six hours post-exercise for HRY, SPN, and SPY trials were 117.9±24.8, 29.5 ±22.2, and 207.2 ±20.4, respectively, which were all significantly different (P < 0.05). Blood lactate at + 1 minute for HRY, SPN, and SPY trials were 3.4±.5, 20.6±1.2, and 19.9±1.3 mM, respectively. These data suggest that an athlete training twice during the day with both anaerobic and aerobic components will have greater muscle glycogen available later in the day if anaerobic training is completed first in the day, providing adequate carbohydrate is consumed between bouts. / School of Physical Education

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Foram realizados dois experimentos com os objetivos de testar a palatabilidade (avaliada pela aceitação ou refuta dos concentrados experimentais, a primeira ação e primeira escolha, a razão de ingestão e a aplicabilidade deste protocolo de teste em experimentos para equinos) e a digestibilidade aparente dos nutrientes e das frações de carboidratos das dietas, com diferentes níveis de inclusão de polpa cítrica no concentrado (0, 7, 14, 21 e 28%) para equinos. Para o experimento de palatabilidade, foram utilizados 10 equinos, em delineamento inteiramente casualisado, enquanto que para o experimento digestibilidade, foram utilizadas cinco diferentes equinos, dispostas em Quadrado Latino 5x5. Foi observado efeito (p<0,01) da primeira ação, sendo que 80% dos animais consumiram o concentrado assim que tiveram acesso. Para a variável primeira escolha, não foi observada diferença (p>0,01) no consumo dos concentrados, porém o concentrado com 7% de inclusão apresentou maior preferência numérica (36,67%), refletida também na maior razão de ingestão (0,4425), o qual apresentou diferença (p<0,01) quando comparado com os demais e evidenciado por apresentar RI >0,30. Não foi observado efeito (p>0,05) dos níveis de inclusão sobre os coeficientes de digestibilidade dos nutrientes bem como das diferentes frações dos carboidratos das dietas, a exceção do carboidrato solúvel que apresentou diferença (p<0,05). Observou-se alta correlação entre os coeficientes de digestibilidade de matéria seca (CDaMS) e fibra em detergente neutro (CDaFDN), entre fibra em detergente ácido (CDaFDA) e fibra em detergente neutro (CDaFDN), e fibra em detergente ácido (CDaFDA) e proteína bruta (CDaDPB). A polpa cítrica pode ser incluída em concentrados para equinos, em níveis de até 28% de inclusão, sem causar efeito deletério sobre a digestibilidade dos nutrientes da dieta, bem como da fração carboidrato da mesma. Níveis inferiores de inclusão, próximos a 7%, favorecem a palatabilidade de dietas com polpa cítrica e sem adição de palatabilizantes (melaço). São necessários maiores estudos para a padronização dos testes de palatabilidade e digestibilidade aparente das frações dos carboidratos das dietas, bem como o efeito metabólico da inclusão de polpa cítrica a dieta de equinos. / Two experiments were conducted out with the objective to test the palatability (measured by the acceptance or refute of the experimental concentrates, the first action and first choice, the highest level of preference, the ratio of intake and the applicability of this protocol in experiments to test horses), apparent digestibility of nutrients and carbohydrate fractions of diets with different levels of citrus pulp inclusion in the concentrate (0, 7, 14, 21 and 28%) for horses. In the palatability experiment there were 10 mares used in a completely randomized design while for the digestibility experiments there were five different mares used arranged in 5x5 Latin Square design. The effect of inclusion on first action was observed (p<0.01) because 80% of the animals promptly were fed the concentrate. There was no difference (p>0.05) for the first choice variable. However, the concentrate with 7% was the most preferred (36.67%). The concentrate with 7% of citrus pulp inclusion presented the highest intake ratio (0.4425; p<0.01) when compared to the others evidenced by IR>0.30. No effect (p>0.05) was observed for the different levels of citrus pulp on the digestibility of nutrients as well as on the different carbohydrates fractions of the diets, except that the soluble carbohydrate presented difference (p<0.05). There was a high correlation between the digestibility of dry matter (CDDM) and neutral detergent fiber (CDNDF), between CDADF and CDNDF, and CDADF and CDDPB. The citrus pulp can be included in concentrates to horses at levels up to 28% inclusion without deleterious effect on the digestibility of nutrients and the carbohydrate fraction thereof. Lower levels of inclusion (7%) may advantage the palatability of diets with citrus pulp and no added flavors (molasses). Nonetheless, more studies are required to standardize the palatability tests and carbohydrate fractions digestibility and the metabolic effect of the citrus pulp inclusion in the horses diet.

A análise de fluxos metabólicos para a produção de PHAMCL por Pseudomonas sp. LFM046 revelou que a baixa eficiência de conversão de carboidratos em PHA (60-70% do valor máximo teórico) deve estar associada à utilização principal da via das pentoses (VP) para o metabolismo de carboidratos. Eficiências significativamente maiores poderiam ser obtidas se uma parcela maior da glicose fosse metabolizada pela via Entner-Doudoroff (ED). Assim, neste trabalho foi realizada a análise de fluxos metabólicos utilizando glicose marcada (C13) e o melhoramento genético de Pseudomonas sp. LFM046 utilizando estratégia de engenharia metabólica. Experimentos com glicose marcada confirmaram um maior fluxo de carboidratos pela VP em relação a ED. A superexpressão de genes específicos de ED em Pseudomonas sp. LFM046 demonstrou apenas pequenos aumentos na eficiência de conversão de carboidratos em PHA pelas linhagens recombinantes. / The metabolic flux analysis for PHAMCL production by Pseudomonas sp. LFM046 revealed that the low efficiency of carbohydrates conversion into PHA (60-70% of the maximum theoretical value) should be associated with the main use of pentose phosphate pathway (PP) for the carbohydrate metabolism. Significantly higher efficiencies could be obtained if a larger portion of the glucose was metabolized via the Entner-Doudoroff (ED). Therefore, the metabolic fluxes analysis was performed in this work using labeled glucose (13C) and the genetic improvement of Pseudomonas sp. LFM046 by using metabolic engineering approach. Experiments with labeled glucose confirmed an increased flow of carbohydrates by PP compared to ED. The overexpression of specific genes from ED in Pseudomonas sp. LFM046 showed only small increases in the efficiency of carbohydrates conversion into PHA by recombinant strains.

O cerrado é o segundo maior bioma do país, ocupando em torno de 20 a 25% do território brasileiro, sendo detentor de grande diversidade vegetal. Entretanto, agressões a áreas de cerrado vêm ocorrendo em escala crescente, o que torna urgente estudos detalhados sobre espécies representativas do bioma. O objetivo deste trabalho foi o de analisar o conteúdo de nutrientes orgânicos das sementes de leguminosas, uma das famílias de maior riqueza no cerrado. Foram analisados lipídios, carboidratos e proteínas de oito espécies: Acosmium subelegans, Anadenanthera peregrina var. falcata, Andira laurifolia, Copaifera langsdorfii, Crotalaria flavicoma, Dimorphandra mollis, Hymenaea stigonocarpa e Inga uraguensis. Em geral, as amostras apresentaram baixos teores de lipídios (aproximadamente 5%) e a composição de ácidos graxos mostrou predominância do ácido linoléico na maioria das espécies e também uma tendência a alta proporção de ácidos graxos saturados, principalmente ácido palmítico. A espécie com maior teor foi Acosmium subelegans (13%), que apresentou valor comparável ao de semente de lupino e sua composição de ácidos graxos é similar aos de óleos de girassol, gergelim e milho. As espécies apresentaram teores consideráveis de açúcares solúveis totais (5-10%). Os rendimentos de amido foram baixos (inferior a 1%), com exceção de Inga uraguensis (17,86%) e Andira laurifolia (56,27%). Esta última apresentou valores similares aos de espécies comumente utilizadas na alimentação, como feijões, ervilha e lentilha. Foram obtidos teores de proteínas de 9 a 30% e as espécies com maiores valores foram Crotalaria flavicoma (25%), Acosmium subelegans (28,34%) e Anadenanthera peregrina var. falcata (30,35%). Essas três espécies possuem teores semelhantes e até superiores aos de algumas leguminosas, como feijão comum, lentilha, ervilha e amendoim, embora seja inferior ao da soja. Entretanto, em Leguminosae é freqüente a presença de diversos fatores anti-nutricionais e tóxicos, que devem ser avaliados antes de se sugerir uma potencial utilização das sementes dessas espécies na alimentação humana e de animais. / Cerrado (Brazilian savanna) is one of the largest biomes in the country, covering about 20 to 25% of the Brazilian territory and housing a wide biodiversity. However, Cerrado vegetation has undergone an increasing degree of aggression. Thus, detailed studies about Cerrado plant species are urgently needed. The aim of this work is to analyse organic nutrients of seeds of representative Cerrado species. Leguminosae is one of the predominant families of the Cerrado flora. Analysis of contents of lipids, carbohydrates, and proteins were carried out, involving eight species: Acosmium subelegans, Anadenanthera peregrina var. falcata, Andira laurifolia, Copaifera langsdorfii, Crotalaria flavicoma, Dimorphandra mollis, Hymenaea stigonocarpa e Inga uraguensis. Regarding most species, the seed samples analysed has low oil contents and the fatty acid compositions are characterized by the predominance of linoleic acid. A trend was observed toward high levels of saturated fatty acids, mainly palmitic acid. Acosmium subelegans showed the highest lipid content (13%), comparable to lupin seeds, and its fatty acid composition was similar to sunflower, sesame and corn oils. All samples analysed contain relatively high amounts of total soluble sugar (5-10%), which include oligosaccharides. Starch contents of most samples were low (below 1%), except for Inga uraguensis (17,86%) and Andira laurifolia (56,27%). The latter value is similar to those reported for commom seed foods, such as beans, peas and lentils. Crude protein contents ranged from 9 to 30%, the species with higher values being Crotalaria flavicoma (25%), Acosmium subelegans (28,34%) and Anadenanthera peregrina var. falcata (30,35%). The protein content of seeds of these species are similar and even higher than those reported for commonly cultivated legumes, such as bean, lentil, pea and peanut, although lower than soybean content. Several antinutritional and toxic components are frequent in Leguminosae seeds, so that the presence of these substances has to be considered before any suggestion regarding utilization of these species in human and animal nutrition may be put forward.