Thesis--Brunswick. / In Periodical Room.

Part of Thesis (PH. D.)--University of Chicago, 1933. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."

Thesis (Ph.D.)--East Carolina University, 2009. / Presented to the faculty of the Department of Pharmacology and Toxicology, the Brody School of Medicine at East Carolina University. Advisor: Brian McMillen. Title from PDF t.p. (viewed April 28, 2010). Includes bibliographical references.

Orientador: Cecília Laluce / Banca: Maria Célia Bertolini / Banca: Sandra Regina Ceccato Antonini / Resumo: Uma levedura selvagem capaz de produzir etanol a temperaturas acima das toleradas pela levedura Saccharomyces cerevisiae pode ser útil ao processo de produção de etanol durante períodos de elevações da temperatura. Leveduras do gênero Issatchenkia orientalis são encontradas em processos industriais de fabricação de pães e bebidas alcoólicas. Esta levedura é capaz de converter glicose e frutose em etanol a temperaturas tão altas quanto 42°C. O presente trabalho teve como objetivo inicial selecionar as melhores linhagens da levedura I. orientalis quanto a sua capacidade de fermentar melaço de cana-de-açúcar e outras fontes de carbono a temperaturas maiores que 40°C. Um segundo objetivo consistiu em produzir etanol a partir de melaço utilizando a melhor linhagem de I. orientalis em co-cultura com a levedura S. cerevisiae. Para cumprir este propósito foram realizados, inicialmente, ensaios qualitativos de assimilação e fermentação com os isolados de I. orientalis da nossa coleção a 40°C. As linhagens ensaiadas mostraram diferentes características quanto a sua capacidade de assimilação (crescimento em meio sólido) e fermentação de sacarose e melaço (ensaio de Durham), apresentando intensidades variadas de crescimento, morfologias diferentes das células e colônias e formação de película no meio liquido. Estes ensaios qualitativos permitiram selecionar a linhagem 195B de I. orientalis para os estudos de fermentação em batelada simples. Esta linhagem foi capaz de assimilar melaço não hidrolisado, melaço hidrolisado, sacarose, frutose e glicerol a 40°C e de fermentar melaço não hidrolisado na mesma temperatura, além de produzir etanol em meio YPD a pH 2,5 e 40°C com pouca perda de viabilidade. Devido à incapacidade da linhagem 195B em fermentar a sacarose contida no melaço, foi estabelecida uma co-cultura desta linhagem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Some wild yeasts that produce ethanol at temperatures above those usually tolerated by the yeast Saccharomyces cerevisiae may be useful to the ethanol production process during periods of elevated temperatures. Issatchenkia orientalis is yeast found in industrial processes for manufacturing of bread and drinks. This yeast is capable of converting glucose and fructose into ethanol at temperatures as high as 42°C. The initial aim of the present work was the selection of the best strains of I. orientalis capable of fermenting sugarcane molasses and other carbon sources at temperatures above 40°C. A second objective was to produce ethanol from molasses using one of the best strain of I. orientalis in co-culture with a strain of S. cerevisiae. To accomplish these purposes qualitative assays of assimilation and fermentation at 40°C were carried out using the isolates of I. orientalis from our collection. Tested strains showed different characteristics regarding their ability to assimilate (growth on solid medium) and to ferment sucrose and molasses (Durham assay), showing a diversity of growth intensities, differences in cell and colony morphologies and film formation in the liquid media. These qualitative assays allowed us to select the strain 195B of I. orientalis for studies using simple batch fermentations. This strain was able to assimilate non-hydrolyzed molasses, hydrolyzed molasses, sucrose, fructose and glycerol at 40°C and to ferment non-hydrolyzed molasses at the same temperature. Moreover, this strain was able to produce ethanol at pH 2.5 and 40°C in YPD with little loss in viability. Due to the inability of strain 195B to ferment the sucrose present in molasses, a co-culture involving this strain and strain IQAr/45-1 of S. cerevisiae was established. The mixed inoculum (1 part of S. cerevisiae : 3 parts of I. orientalis) allowed to ferment molasses at 42°C with little... (Complete abstract click electronic access below) / Mestre

The aim of the work presented in this thesis was to assess the protective properties of the bioflavanoid drug, (+)-catechin, and its palmityl ester, 3-palmitoyl-(+)-catechin, against ethanol hepato-toxicity (ie: fatty liver) in the rat. In initial experiments, both (+)-catechin compounds were found to protect against the hepatic lipid accumulation (mainly triglyceride) after acute ethanol dosing, and after long-term feeding of ethanol in a liquid diet. In the latter situation, 3-palmitoyl-(+)-catechin was significantly more effective than (+)-catechin itself at preventing fatty liver, probably as a result of its greater lipid solubility and longer half-life in the liver tissue. Published work suggested two possible mechanisms of action for the (+)-catechin compounds against ethanol hepatotoxicity. Firstly, the ability of the drugs to correct the elevated hepatic NADH:NAD ratio (redox-state) after ethanol dosing may limit steatosis. Secondly, free radical scavenging properties may prevent liver injury occurring as a result of ethanol-induced lipid peroxidation. Acute experiments were performed which confirmed that the (+)-catechin compounds corrected the redox-state change after acute ethanol administration, but subsequent studies in which correction of the redox-state by Naloxone or Methylene Blue was found to have little influence on ethanol-induced steatosis, suggested that this was not the mechanism of action of the drugs. Synthetic antioxidants (free radical scavengers) were found to prevent both acute and chronic ethanol-induced fatty liver, under the same experimental conditions as those under which the (+)-catechin compounds afforded protection, without reversing the redox-state change after ethanol dosing. 3-Palmitoyl-(+)-catechin was then shown to prevent ethanol-induced hepatic lipid peroxidation (measured as mitochondrial diene conjugates and liver malonaldehyde levels) after acute ethanol dosing, at the same time as preventing triglyceride accumulation. As other effects of the compounds which might influence fat accumulation after ethanol were excluded (eg: inhibition of ethanol metabolism or lowering of liver acetaldehyde concentrations), it was concluded that the (+)-catechin compounds protect against alcoholic fatty liver in rats by inhibiting ethanol-induced lipid peroxidation, and the possible consequence of the latter (ie: mitochondrial damage and impaired fatty acid oxidation), rather than acting through modulation of the redox-state. The findings here cast doubts on the commonly-quoted 'redox-state' mechanism for fatty liver production by ethanol, and support the lipid peroxidation hypothesis for alcoholic liver injury.

Various indicators of flooding damage were investigated to assess their possible use as monitors of the effects of flooding. The effects of anoxia on root leakage and needle chlorophyll content were observed using seedlings of Pinus contorta and Picea sitchensis in water culture. Wood-cores were collected from the trunks bases of Pinus sylvestris trees on sites of various wetness at Tentsmuir, Fife, and their ethanol contents determined. Samples from trees growing in the wetter areas contained more ethanol than those from the dry areas. This information suggested that ethanol content was the most likely indicator of those investigated, to be worth examining for use as a monitor of anaerobic conditions and flooding damage. Ethanol levels in wood cores could be related to those in the root, and so a useful field sampling method was established. Further cores were taken from trees of Pinus sylvestris and Picea abies on three sites at Tentsmuir, throughout the year. Ethanol could always be detected, but seasonal fluctuations could be observed. Concentrations were highest at times of high water table (i.e. low oxygen availability), and high metabolic activity (i.e. high oxygen demand). In glasshouse experiments, seedlings of Pinus contorta (flood-tolerant) and Picea sitchensis (flood-intolerant), were maintained in aerated or unaerated water culture, and flooded or unflooded pots. Cessation on aeration caused an immediate increase in root ethanol concentrations in both species, but this was nine fold greater in Picea sitchensis, indicating a difference in response to anoxia by flood-tolerant and flood- intolerant species. The toxic nature of ethanol was investigated in the same conditions, but with ethanol added to the culture medium, Root leakage, needle chlorophyll, root tip viability, and root respiration were investigated. Respiration data indicated that, unlike Picea sitchensis, Pinus contorta could metabolise ethanol in anaerobic conditions. It is suggested that flooding tolerance is due to a combination of the abilities to transport oxygen from the shoot to the root, to oxidise ethanol formed, and to control actual rate of glycolysis and ethanol production. Flood intolerant species do not possess these abilities, and may even suffer increased rate of ethanol production in anaerobic conditions. The use of ethanol as a monitor of the effects of flooding and the observation of change in rate of ethanol production in anaerobic conditions as a method of screening seedlings for flooding tolerance, are exciting possibilities for the future.

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Made available in DSpace on 2014-06-11T19:23:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-30Bitstream added on 2014-06-13T20:29:51Z : No. of bitstreams: 1 silva_dfc_me_arafcf.pdf: 568183 bytes, checksum: 73d6ec26cd4c744632d3e598a44b3af9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / A produção de bioetanol industrial pela levedura Saccharomyces cerevisiae continua em crescimento devido à demanda energética e ambiental. Considerando a importância da produção de bioetanol para a economia nacional é importante conhecer a levedura Saccharomyces cerevisiae, bem como as diversas formas de estresse que estas podem sofrer, suas respostas, os tipos de processos de fermentação, desta forma, foram testados a resistência dos isolados aos principais fatores de estresse (osmótico, térmico e etanólico) e a sua capacidade de produzir etanol. Estas informações serão necessárias para selecionar novas linhagens de leveduras, no intuito de melhorar a produção de etanol. Para tanto, foram selecionadas de uma safra de cana-de-açúcar que utiliza fermento de panificação como inóculo inicial, 34 leveduras da cuba e da dorna de fermentação de uma usina da região de Araraquara. Dessas, 28 isolados foram identificados como Saccharomyces cerevisiae a partir das técnicas moleculares de PCR e PCR-RFLP. Três isolados foram caracterizados e selecionados como resistentes a alta temperatura, alta concentração de açúcares e alta concentração de etanol. Porém somente o isolado denominado ZFC4 pode ser considerado como um bom inóculo para iniciar um processo fermentativo para a produção de bioetanol, pois este apresenta um alto rendimento de etanol, resistência a alta temperatura e às altas concentrações de etanol, mostrando-se mais tolerante que a linhagem de referencia PE-2. Para uma discriminação genética dos isolados selecionados foi realizado sequenciamento do gene rRNA da região 25S, 18S e 5.8S, porém os resultados não puderam elucidar sobre os seus diferentes comportamentos fenotípicos. Linhagens industriais apresentam uma constituição genética complexa... / Bio-ethanol production by yeast Saccharomyces cerevisiae continues a growing industry due to energy and environmental demands. Considering the importance of bioethanol to the national economy is important to know the yeast Saccharomyces cerevisiae, as well as various forms of stress they may suffer, their responses, types of processes of fermentation, thus, we tested the resistance of the isolates the main factors of stress (osmotic, thermal and ethanol) and the ability to produce ethanol. To somewhat of a crop of cane sugar were isolated 34yeasts from the vat and a tank of fermentation of the plant. These, 28 isolates were identified as Saccharomyces cerevisiae from PCR and PCR-RFLP. Three isolates were characterized as resistant to high concentration of sugar (20% glucose and sucrose) and 39°C in presence 12% ethanol. However, only the isolated ZFC4 can be considered as a good inoculum to start a fermentative process for the production of ethanol because it has a high ethanol yield and greater resistance to high temperature and high ethanol concentrations and proved to be more tolerant than the reference strain of Pe-2. For a genetic discrimination of selected isolates was performed sequencing gene rRNA of the region 25S, 18S and 5.8S, however the results could not elucidate their different phenotypic behavior. Industrial strains have a complex genetic constitution, molecular tools that are needed to understand the survival capacity of these strains to stress throughout the fermentation process. To that end, after the characterization of genotypes and phenotypes of Saccharomyces cerevisiae isolates selected genes differentially expressed during the fermentation test, were identified by technique known as RDA (Representational Difference Analysis). In this context, 196 clones were... (Complete abstract click electronic access below)

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