Rats given L-Ascorbic Acid in their drinking water prior to and during starvation did not develop severe ulceration in the glandular portion of their stomachs. Control rats which were either nontreated or given deactivated L-Ascorbic Acid developed severe stomach pathology on the starvation regimen. The present study was based on the finding that food deprivation results in severe rumenal ulceration in rats. Given that L-AA is essential in maintaining tissue integrity and that ulcers are examples of tissue degeneration, the L-AA in large amounts could retard, or prevent, the formation of starvation induced stomach ulcers in rats. The results show that large amounts of active L-AA were beneficial in maintaining the integrity of rat gastrointestinal tissue exposed to starvation conditions which, in the vitaimin's absence, induces deterioration.

Despite the common usage of high-dose vitamin C among breast cancer patients, the published medical literature is not in agreement as to how mega-dose vitamin C may interact with conventional therapy to affect clinical outcomes. The purpose of this study was to investigate the interaction of mega-dose vitamin C with radiation therapy and with doxorubicin in the treatment of breast cancer. Cultures of EMT6 mouse mammary tumor cells were treated concurrently with varying dose of vitamin C and either radiation or doxorubicin. A clonogenic assay was then performed to determine the surviving fraction of the cells. The surviving fractions of cells in cultures receiving different doses of vitamin C were compared among themselves as well as with controls and dose response curves were generated. Results show that ascorbic acid administered in concentrations of 1 mM or 10 mM 4 hours before x-irradiation protected the cells from radiation-induced cytotoxicity. The dose-modifying factors for 1 mM and 10 mM ascorbic acid as compared to controls were 1.23 and 1.37 respectively. These results support the hypothesis that mega dose vitamin C, when taken concurrently with radiation therapy, protects cancer cells from the cytotoxic effects of ionizing radiation. No evidence was found to suggest that mega-dose vitamin C alters the antineoplastic effects of doxorubicin.

ABSTRACT Three different genotypes of sugar beet (diploid, triploid and tetraploid) / 4 varieties from diploid and triploid genotypes Soraya (KWS8123) and Leila (diploid), Visa (H68121) and Kassandra (triploid) and 2 lines from tetraploid genotype &Ccedil / BM315 and EA2075 (tetraploid) were used for investigating the effects of ploidy level on plant regeneration. Within three sugar beet genotypes, with respect to the treatments, triploids or tetraploids were found to respond to treatments significantly different when compared with diploids. The responses of polyploids were superior over the responses of diploids. Moreover, varieties from same genotype responded differently to treatments. Two types of calli were obtained / one white and friable with regenerative capacity and the other green and compact with no regenerative capacity. Concentration of sucrose on callus development was observed to be important. High concentration of sucrose (30 g/L) was found to cause discoloration and irresponsiveness of formed calli at callus enlargement and subsequent shoot regeneration stages. Therefore, low concentration (10 g/L) is advised to be used at these stages / although this caused less callus induction. Although initially used for the prevention of tissue discoloration, L-ascorbic acid inclusion into the medium was found to be positively affecting the regeneration capacity. When used at 20 mg/100 mL concentration, the only two spontaneous shoots from the tetraploid EA2075 line were obtained. Subsequently, these shoots were successfully rooted and whole plants were obtained. The effect of silver nitrate, in combination with L-ascorbic acid, on the prevention of sugar beet tissue discoloration was investigated. Unfortunately, the symptoms of discoloration did not diminish. Moreover, callus formation was reduced and the subsequent shoot recovery could not be achieved. Since a total of 3456 explants were used during this study, and only 2 whole plants were regenerated, the efficiency of plant recovery was calculated as a rather low value of 0.058 %.

Effects of various levels of L-ascorbic acid (L-AA) (12 and 25 mg) in ovo injected at 17 and 18 days of incubation, on embryonic and posthatch physiological variables in Ross 708 broilers were investigated. There were no significant treatment effects on the hatchability or serum concentrations of L-AA in the broilers. Eye L-AA concentrations were higher, and plasma nitric oxide levels were lower in male chicks treated in ovo with 12 mg of L-AA. While exposed to elevated atmospheric NH3 levels, the in ovo injection of 12 mg of L-AA increased the body weight gain and decreased the feed conversion ratio of the broilers from 0 to 28 days of age (doa). Decreased tracheal attenuation incidence was also experienced at 0 doa in the in ovo injected L-AA groups, and tracheal inflammation was significantly reduced at 28 doa in response to the in ovo injection of 12 mg of L-AA.

Made available in DSpace on 2015-03-26T13:52:00Z (GMT). No. of bitstreams: 1 texto completo.pdf: 996773 bytes, checksum: 7322b4697c096a6f17a4388ca498fede (MD5) Previous issue date: 2014-02-17 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The L-ascorbic acid (ALA) is produced naturally by plants from D-glucose. Yeasts synthesize a similar metabolite, D-eritroascorbic acid (ADEA). Although this compound does not show activity against scurvy, it contains an antioxidant function, but it is produced in low concentrations by the microorganism. Recently, in order to make yeasts are capable of converting D-galactose D-lactose from cheese whey into ALA, the wild strain Kluyveromyces lactis CBS2359 has been transformed with genes that integrate the L-galactose biosynthesis pathway, isolated from Arabidopsis thaliana. In the presence of intermediate L-galactose, ALA can be synthesized by yeast with enzymes responsible for ADEA production. It has been demonstrated that the engineered strain JVC 1-56 was able to synthesize ALA compared to the wild type, but the yield was still low. In this regard, studies to assist the increased of ALA production are relevant. Once the engineered ALA pathway and native cell wall formation pathway of K. lactis have a common intermediate, GDP-D-mannose, we need to evaluate the effect of uncoupling of vitamin C synthesis route of the growth that requires constant wall synthesis. Moreover, considering the antioxidant properties of ALA, the expectation is that the production of this metabolite increase when JVC 1-56 is exposed to a oxidative stress condition by menadione. In this context, this study investigated the both physiological conditions, using the media Yeast Galactose Base (YGB) and ultrafiltered cheese whey (SQU - byproduct of cheese industry that predominates lactose as carbon source). It was analyzed that Kluyveromyces lactis JVC 1-56 produces higher yields of ALA when it is grown for 96 hours in batch culture in the middle YPGal. Cultivation at low growth rates (0.04 h-1) predisposes the cells to synthesize more ALA per unit cell mass (0.80 mg/mg). However, the yield of continuous culture operated as quimostato, limiting the substrate nitrogen, still proved to be lower than expected in the batch (1.94 mg/mg). Oxidative stress by 12.5 mM menadione on K. lactis JVC1 -56, in the conditions applied, was not effective in the increasing the ALA production (1.47 mg/mg). Still, ADEA yield was higher than ALA in two strategies: 1.37 mg/mg at 0.21 h-1 in culture under steady state, 8.52 mg/mg in batch under oxidative stress and 10.33 mg/mg in the batch in the absence of oxidizing agent, indicating that ADEA may be in a more stable configuration than vitamin C. Finally, the permeate cheese whey remains a prospect for the conversion of lactose into a biotechnological product of higher value aggregate. / O ácido L-ascórbico (ALA) é produzido naturalmente por plantas a partir de D-glicose. Leveduras sintetizam um metabólito semelhante, o ácido D-eritroascórbico (ADEA). Embora este composto não mostre atividade contra o escorbuto, ele contém uma função antioxidante, mas é produzido pelo micro-organismo em baixas concentrações. Recentemente, com a finalidade de fazer as leveduras serem capazes de converter o componente D-galactose da D-lactose do soro de queijo em ALA, a linhagem selvagem de Kluyveromyces lactis CBS2359 foi transformada com genes, que integram a via de biossíntese de L-galactose, isolados de Arabidopsis thaliana. Na presença do intermediário L-galactose, ALA pode então ser sintetizado pela levedura com as enzimas responsáveis pela produção de ADEA. Foi demonstrado que a linhagem engenheirada JVC 1-56 foi capaz de sintetizar ALA em comparação com a selvagem, mas com baixo rendimento. Neste sentido, estudos que auxiliem o aumento da produção de ALA são relevantes. Uma vez que a via engenheirada da síntese de ALA e a via nativa da formação da parede celular de K. lactis possuem um intermediário comum, GDP-D-manose, faz-se necessário avaliar o efeito do desacoplamento da produção de ALA do crescimento que requer constante síntese da parede. Além disso, considerando a propriedade antioxidante do ALA, a expectativa é de que a produção deste metabólito aumentasse quando JVC 1-56 fosse exposta a uma condição de estresse oxidativo por menadiona. Neste contexto, este trabalho investigou as condições fisiológicas mencionadas utilizando os meios Yeast Galactose Base (YGB) e soro de queijo ultrafiltrado (SQU - subproduto de indústrias de queijo em que predomina lactose como fonte de carbono). Foi averiguado que Kluyveromyces lactis JVC 1-56 produz ALA com rendimentos maiores quando cultivada por 96 horas em batelada no meio YPGal. O cultivo em baixas velocidades de crescimento (0,04 h -1) predispõe as células a sintetizar mais ALA por unidade de massa celular (0,80 mg/mg). Entretanto, o rendimento da cultura contínua operada como quimostato, tendo nitrogênio como substrato limitante, ainda mostrou ser inferior ao previsto na batelada (1,94 mg/mg). Já o estresse oxidativo por 12,5 μM de menadiona sobre K. lactis JVC1- 56, nas condições aplicadas, não foi eficaz no aumento da produção de ALA (1,47 mg/mg). Ainda, o rendimento de ADEA foi superior ao de ALA nas duas estratégias: 1,37 mg/mg a 0,21 h-1 na cultura sob regime permanente, 8,52 mg/mg na batelada sob estresse oxidativo e 10,33 mg/mg na batelada na ausência do agente oxidante, indicando que ele pode estar em uma configuração mais estável do que a vitamina C. Finalmente, o permeado do soro de queijo continua sendo uma perspectiva para a conversão da lactose em um produto biotecnológico de maior valor agregado.

<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>U radu je spektrofotometrijski ispitivana brzina oksidacije L-askorbinske kiseline. Tok reakcije je praćen snimanjem UV apsorpcionih spektara termostatiranih rastvora L-askorbinske kiseline u puferima različitih vrednosti rN: acetatnom (4-6). fosfatnom (5-8). fosfatno-citratnom (6-8), boratnom (8-11). glicinskom (9-11) i univerzalnom (4-11) !zveden je jednostavan oblik kinetičke jednačine reakcije vi&scaron;eg i razlomljenog reda. Dobijena jednačina je univerzalna, jer obuhvata jednačine nultog, prvog, drugog, trećeg i razlomljenog reda izračunate su vrednosti reda reakcije i one variraju sa promenom vrednosti rN unutar jednog puferskog sistema. Veza između vrednosti konstanti brzine oksidacije L-askorbinske kiseline i vrednosti rN ispitivanih pufera je linearna do vrednosti rN=10.00. Vrednosti koeficijenta pravca prave su različite za ispitivane pufere. Vrsta anjona prisutna u puferu kao i prisusutvo jona metala u kori&scaron;ćenim hemikalijama utiču na vrednosti konstante brzine oksidacije L-askorbinske kiseline i one su različite u raznim puferima istih vrednosti rN. Vrednosti konstante brzine oskidacije L-askorbinske kiseline su največe u univerzalnom puferu pri svim vrednostima rN. Prisutna sme&scaron;a anjona manje utiče na oksidaciju L-askorbinske kiseline nego pojedinačni anjoni, verovatno zbog među- sobnih interakcija.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>The paper deats with the spectrophotometric study of L-ascorbic acid oxidation rate. The course of reaction has been observed by recording the UV absorption spectra of thermostated solution of L-ascorbic acid in buffers with different рН values: acetate (4-6), phosphate (5-8), phosphate-citrate (6-8), borate (8-11), glycine (9-11) and universal (4-11). A simple form of kinetic eguation of higher and fractional order reaction has been observed. The obtained eguation is universal as it comprises the eguations of zero, first, second, third and fractional order. The reaction order values have been calculated and they vary with change of рН values within each buffer system. The relation between the values of L-ascorbic acid oxidation rate constants and рН value of the studied buffers is linear up to рН value = 10.00. The straight line stopes are different for investigated buffers. The anion type present in a buffer as wett as the presence of metal ions in applied chemicals affect the values of L-ascorbic acid oxidation rate constant and they are different in different buffers with the same рН values. The values of L-ascorbic acid oxidation rate constant are the highest in the universal buffer at all рН values. The present anion mixture affects the L-ascorbtc acid oxidation to a tesser degree than single anions, presumabty due to mutuat interactions.</p>

The transcription factor hypoxia-inducible factor 1 (HIF1) is the crucial regulator of genes that are involved in metabolism under hypoxic conditions, but information regarding the transcriptional activity of HIF1 in normoxic metabolism is limited. Different tumor cells were treated under normoxic and hypoxic conditions with various drugs that affect cellular metabolism. HIF1ff was silenced by siRNA in normoxic/hypoxic tumor cells, before RNA sequencing and bioinformatics analyses were performed while using the breast cancer cell line MDA-MB-231 as a model. Differentially expressed genes were further analyzed and validated by qPCR, while the activity of the metabolites was determined by enzyme assays. Under normoxic conditions, HIF1 activity was significantly increased by (i) glutamine metabolism, which was associated with the release of ammonium, and it was decreased by (ii) acetylation via acetyl CoA synthetase (ACSS2) or ATP citrate lyase (ACLY), respectively, and (iii) the presence of L-ascorbic acid, citrate, or acetyl-CoA. Interestingly, acetylsalicylic acid, ibuprofen, L-ascorbic acid, and citrate each significantly destabilized HIF1ff only under normoxia. The results from the deep sequence analyses indicated that, in HIF1-siRNA silenced MDA-MB-231 cells, 231 genes under normoxia and 1384 genes under hypoxia were transcriptionally significant deregulated in a HIF1-dependent manner. Focusing on glycolysis genes, it was confirmed that HIF1 significantly regulated six normoxic and 16 hypoxic glycolysis-associated gene transcripts. However, the results from the targeted metabolome analyses revealed that HIF1 activity affected neither the consumption of glucose nor the release of ammonium or lactate; however, it significantly inhibited the release of the amino acid alanine. This study comprehensively investigated, for the first time, how normoxic HIF1 is stabilized, and it analyzed the possible function of normoxic HIF1 in the transcriptome and metabolic processes of tumor cells in a breast cancer cell model. Furthermore, these data imply that HIF1 compensates for the metabolic outcomes of glutaminolysis and, subsequently, theWarburg effect might be a direct consequence of the altered amino acid metabolism in tumor cells.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Biomedical Technology in the Faculty Health and Wellness Sciences at the Cape Peninsula University of Technology, 2013 / The accurate and consistent measurement of antioxidants is crucial to evaluating their biological role in the prevention and delay of cancer and other pathological conditions. Hence, the performance of the analytical method utilized should be evaluated for acceptable levels of accuracy, precision and other performance parameters according to internationally accepted standards. Additionally, the measure and influence of existing errors should be evaluated and the method optimized to reduce such errors. In furtherance of this vital aim, this research project sought out to optimize and validate two bio-analytical assays for the measurement of total antioxidant capacity and L-ascorbic acid (L-AA), respectively in food commodities. The validation procedure was performed in accordance with ISO 17025 international standard. The first study in this thesis evaluated, optimized and validated the hydrophilic oxygen radical absorbance capacity (H-ORACFL) assay using fluorescein for total antioxidant capacity in various food and beverage products. The assay demonstrated good results with regard to accuracy, precision, linearity, specificity, limits of detection (LOD) and quantification (LOQ) and robustness. The extraction solvent (60% ethanol) recovered excellent antioxidant yields for most samples tested. The optimization of the method in terms of temperature and sample usage on the micro-plate significantly (p<0.05) reduced errors and subsequently improved precision substantially.

Made available in DSpace on 2015-04-17T14:49:32Z (GMT). No. of bitstreams: 1 parte1.pdf: 3805618 bytes, checksum: c5283752b1a8775c6dd8cef062f7c370 (MD5) Previous issue date: 2009-11-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of this research was to evaluate the physical, physical-chemical, bioactive, and sensorial attributes of the first Brazilian seedless grapes (Vitis vinifera L.) varieties 'BRS Clara', 'BRS Linda', 'BRS Morena', and Advanced Selection 8, compared with the North American 'Crimson Seedless'. Three experiments had been carried out. For the first one, taking into account the Normative Brazilian/2002 and the requirements for exportations, it was determined that Advanced Selection 8 develops large cluster, inserted in class 2, with dark reddish berry, caliber 20, and ellipsoid format; 'BRS Morena' presents cluster of medium size, in class 2, with berry colored of black nuance, caliber 20, and format between ellipsoid and globoid; 'BRS Linda' with large cluster, in class 2, light-green color, and 'Crimson Seedless' with pink colored and small cluster inserted in class 1, offer berries in caliber 18 with ellipsoid formats; 'BRS Clara' develops medium size cluster in class 2, berry with caliber, green yellowish green color and a format elongated ellipsoid. All of these grapes meet the standards for national market that demands a minimum of 12 millimeters of diameter. On the other hand, 'BRS Clara' does not meet the minimum diameter demanded for exportations. The red grapes ' BRS Morena' e 'Crimson Seedless' develop the firmest berries. The hydrogenionic potential, titratable acidity and soluble solids content meet the official standard values. The largest clusters are significantly less acid and present higher soluble solid/titratable acidity ratio, inferring to be the sweetest when mature. For the second experiment, it was determined and correlated the content of acid Lascorbic, total phenolic composites, trans-resveratrol, and the total antioxidative capacity of the studied grapes. All grape samples presented low acid L-ascorbic contents. The white 'BRS Clara' presents marked content of total phenolic compounds, followed by the white 'BRS Linda', in third position are the red ones: Advanced Selection 8, 'BRS Morena', and 'Crimson Seedless'. 5 Grapes presented distinct contents of trans-resveratrol in this following order of superiority: 'BRS Morena', 'Crimson', Advanced Selection 8, 'BRS Linda', and 'BRS Clara'. Trans-resveratrol seems to provide varietal identity. Red grapes presented higher contents of trans-resveratrol. 'BRS Clara', ' Crimson Seedless', and 'BRS Linda', similarly, presented the highest antioxidative capacity and the color of the grape did not influence on that. The contents of total extractable phenolic compounds influenced positively on the antioxidative capacity. Grapes presenting larger contents of total extractable phenolic compounds presented lower content of transresveratrol. For the third experiment it was used the Quantitative Descriptive Sensorial Analysis, by means of selected and trained judges. On the global quality, 'BRS Morena' was superior than others grapes evaluated, while Advanced Selection 8 was in second position, and 'BRS Linda' and 'Crimson Seedless' occupied the third position, while 'BRS Clara' showed the most inferior sensorial quality. The general characteristics flavor, with large superiority, followed, in this order, by the strongest tonality, the red color, the most spherical format, the highest firmness, succulence, crispness, and sweetness contributed positively with the global quality. The bitter taste and the sensorial acidity, in this sequence of intensity, were the attributes of larger negative influence. The results for physical and physical-chemical evaluations, together, reflect significantly the sensorial perceptions. Therefore, once inserted in the official standards of identity and quality, beside the varietal characteristic flavor, producers must prefer to produce grapes of stronger tone, larger sizes, and more spherical or globular formats. / O objetivo desta pesquisa foi avaliar os atributos físicos, físico-químicos, bioativos e sensoriais das primeiras variedades de uvas (Vitis vinifera L.) sem sementes brasileiras, 'BRS Clara', 'BRS Linda' e 'BRS Morena', mais a Seleção Avançada 8, comparadas com a norte-americana 'Crimson Seedless'. Foram conduzidos três experimentos. Assim, com o primeiro considerando as Normativas brasileiras/2002 e as exigências para exportações, determinou-se que a Seleção Avançada 8 possui cacho grande na classe 2 com baga avermelhada escura, calibre 20 e formato elipsóide; A 'BRS Morena' apresenta cacho médio na classe 2, com baga colorida de nuança preta, calibre 20 e de formato elipsóide a quase globoso; a 'BRS Linda' com cacho grande, classe 2, de cor verde clara e a 'Crimson' com cacho róseo, pequeno na classe 1 oferecem bagas de calibre 18 e com formatos elipsóides; a 'BRS Clara' possui cacho médio e de classe 2, com baga de calibre 14, tom verde amarelado e de formato elipsóide alongado. Todas atendem o mercado nacional quanto aos diâmetros mínimos de 12 milímetros. A 'BRS Clara' não atende os diâmetros exigidos para exportações. As uvas tintas 'BRS Morena' e 'Crimson Seedless' dispõem das bagas mais firmes. O potencial hidrogeniônico, a acidez titulável e os teores de açúcares solúveis atendem aos padrões oficiais. Os cachos maiores são os menos ácidos e apresentam a melhor relação de sólidos solúveis/acidez titulável, inferindo serem os mais doces, quando maduros. O segundo experimento determinou e correlacionou os teores de ácido L-ascórbico, compostos fenólicos totais extraíveis, trans-resveratrol e a capacidade antioxidante total das uvas estudadas. Todas as amostras apresentaram baixos conteúdos de ácido L-ascórbico. A branca 'BRS Clara' apresenta destacado teor de compostos fenólicos totais extraíveis, seguida pela branca 'BRS Linda', em terceiro lugar encontram-se as tintas Seleção 8, 'BRS Morena' e 3 'Crimson'. As uvas apresentaram conteúdos distintos do trans-resveratrol e nessa ordem de superioridade: 'BRS Morena', 'Crimson', Seleção Avançada 8, 'BRS Linda' e 'BRS Clara'. O trans-resveratrol parece conferir identidade varietal. As tintas apresentaram maiores conteúdos de trans-resveratrol. A 'BRS Clara', 'Crimson' e 'BRS Linda', igualmente, apresentaram a maior capacidade antioxidante. A cor não interferiu na capacidade antioxidante. Os compostos fenólicos totais influenciaram positivamente na capacidade antioxidante. Uvas com maiores quantidades de compostos fenólicos totais extraíveis, apresentam menores teores de transresveratrol. No terceiro experimento utilizou-se a Análise Sensorial Descritiva Quantitativa, mediante julgadores selecionados e treinados. Quanto à qualidade global, a 'BRS Morena' apresentou-se superior, a Seleção Avançada 8 destacou-se em segundo lugar, enquanto, a 'BRS Linda' e 'Crimson Seedless' ocuparam o terceiro lugar e a BRS Clara' foi de qualidade inferior, sensorialmente. O sabor geral característico, com ampla superioridade, seguido na ordem, pela tonalidade mais forte, a cor tinta, o formato mais esférico, a maior firmeza, suculência, crocância e doçura contribuíram positivamente com a qualidade global. O amargor e a acidez sensorial, nesta seqüência de intensidade, foram os atributos de maior influência negativa. Os resultados das avaliações físicas e físico-químicas, em conjunto, refletem com significância as percepções sensoriais. Uma vez, dentro dos padrões de identidade e qualidade oficiais, além do sabor varietal característico, os produtores devem preferir produzir uvas de tons mais fortes, tamanhos maiores e de formatos mais esféricos ou globosos.