Este estudo visou quantificar os teores de fosfato total, inorgânico e orgânico no caldo proveniente de diferentes alturas (região basal, mediana e apical) do colmo de três variedades de cana-de-açúcar, além de buscar levantar a ocorrência de myo-inositol hexafosfato (ácido fítico) em colmos de cana-de-açúcar. A composição química e tecnológica de colmos de cana-de-açúcar está relacionada com as características genéticas da variedade. Os colmos da cana-de-açúcar são compostos de fibra e caldo absoluto. O caldo contém cerca de 25% de sólidos solúveis, dos quais a sacarose se destaca. Na área agrícola o elemento fósforo é importante principalmente no metabolismo fotossintético da planta. No caldo de cana-de-açúcar se encontra nas formas mineral e orgânica, exercendo uma função chave no processo de clarificação do caldo para produção de açúcar, sendo também importante nos processos de fermentação alcoólica. Em grãos de cereais e leguminosas, estudos com o elemento fósforo, ou mais especificamente o myo-inositol hexafosfato (ácido fítico), têm mostrado algumas características antinutricionais, antioxidantes e anticarcinogênicas, que o ácido fítico possui quando complexado com certos cátions. Foram utilizadas as variedades SP 82-3530, SP 83-5073 e RB 83-5486 de cana-de-açúcar para as análises de fosfatos, sendo os colmos das mesmas divididos em região basal (3/8), mediana (3/8) e apical (2/8). Para as análises de ácido fítico foi utilizada apenas a variedade SP 82-3530, sendo os colmos desta analisados integralmente, com e sem casca, e divididos em nós e internódios com e sem casca. O caldo dos colmos de cana foi extraído em prensa hidráulica. As variedades apresentaram teores que variaram de 370 a 936 mg P2O5 total por litro de caldo. As regiões do colmo apresentaram valores decrescentes para os três tipos de fosfato da base para o ápice do colmo. O fosfato orgânico representou aproximadamente 5% do total. As porcentagens dos teores de fosfato orgânico em relação ao total, apresentaram um gradiente crescente da região basal para a apical. A análise de ácido fítico, por este ter apresentado teores insignificantes no caldo e na cana, ficou prejudicada pela metodologia aplicada, a qual se mostrou inadequada. / The objective of the present study was to estimate total, inorganic and organic phosphate amounts in the juice of stalk segments (basal, middle and top) of three sugarcane varieties, as well as assessing the presence of myo-inositol 6-phosphate (phytic acid) in sugarcane stalks. The chemical and technological compositions of sugarcane stalks are linked to the genetic characteristics of each variety. Sugarcane stalks are composed of fiber and absolute juice. The juice contains about 25% of soluble solids, mainly sucrose. Phosphorus is an important element in agriculture, due to its participation in the photosynthetic metabolism of plants. Phosphorus is found in its mineral and organic forms in the sugarcane juice and plays a key role in the clarification and fermentation processes for the production of sugar and alcohol. Studies on phosphorus, or rather, on myo-inositol 6-phosphate (phytic acid), in cereal and leguminous grains have evidenced some anti-nutritious, antioxidant and anticarcinogenic characteristics of the phytic acid when complexed with certain cations. Basal (3/8), middle (3/8) and top (2/8) stalk segments from SP 82-3530, SP 83-5073 and RB 83-5486 sugarcane varieties were analyzed for their phosphate amounts. Only stalk segments from the variety SP 82-3530, separated in nodes and internodes, peeled or not, were analyzed for phytic acid amounts. The juice of sugarcane stalks was extracted on hydraulic press. Total P2O5 varied from 370 to 936 mg per liter of juice. The three types of phosphate showed decreasing amounts from the bottom to the top of the stalk. Organic phosphate constituted approximately 5% of total phosphate. Percentages of organic phosphate in relation to total phosphate amounts increased gradually from the basal to the top stalk segments. As phytic acid was found in insignificant amounts, the assessment of its presence was limited by the methodology used, which showed to be inappropriate.

Orientador: Reges Heinrichs / Co-orientador: Paulo Alexandre Monteiro de Figueiredo / Banca: Cristina Andrighetto / Banca: Carlos Sergio Tiritan / Resumo: O fósforo é considerado um elemento essencial para a cana-de- açúcar, assumindo grande importância no enraizamento, perfilhamento e na produtividade final de colmos. Com o objetivo de avaliar os efeitos da fosfatagem em pré-plantio nas condições químicas do solo e no desenvolvimento da cultura da cana- de-açúcar, foi realizado um experimento com a variedade RB 86 7515, junto à unidade produtora da Usina Santa Mercedes, em Tupi Paulista, Estado de São Paulo. O delineamento experimental foi em blocos ao acaso com 4 repetições, no esquema fatorial 2 x 4, sendo duas fontes de fósforo (fosfato decantado e Fosfato monoamônico) e quatro doses de fósforo (0; 80; 120; 160 kg ha -1 P 2 O 5 ). Em folhas coletadas aos 120 dias após o plantio foi realizada a diagnose foliar (folha +1). Aos 120, 240 e 3 dias após o plantio foram avaliadas as seguintes características: espessura da epiderme abaxial, espessura da epiderme adaxial, espessura do mesofilo, diâmetro dos vasos floemáticos e diâmetro dos vasos floemáticos. Aos 362 dias após o plantio foi realizada a colheita manual dos colmos integrais, em área total das parcelas para a determinação de massa verde de forragem (t ha -1 ). A adubação fosfatada em pré-plantio apresentou resposta positiva para produção de massa verde de forragem, independentemente das fontes utilizadas. As melhores respostas foram alcançadas em doses a partir de 120 Kg de P 2 O 5 ha -1 . O estado nutricional da planta não foi influenciado pelas fontes e doses de fósforo. Houve influência das doses de fósforo no desenvolvimento dos vasos condutores foliares da cana-de-açúcar por ocasião da colheita. Doses acima de 120 kg de P 2 O 5 ha -1 aumentam o ATR t ha -1 da cana-de-açúcar, o que não ocorreu com %fibra, %brix, %POL, %Pureza e ATR kg t -1 . As fontes e doses testadas de fósforo aumentaram a disponibilidade de fósforo no solo.A fonte Fosfato monoamônico reduziu o pH do solo e aumentou a ... / Abstract: Phosphorus is considered an essential element for sugarcane and it has great importance in rooting, tillering and on yield of cane. With the objective of evaluation of the effects of phosphate, pre-planting in soil chemical conditions and the development of the sugarcane, an experiment with the variety RB86 7515 was conducted by the producing unit of Usina Santa Mercedes, Tupi Paulista, São Paulo. The experimental design was a randomized block with four replications in a factorial 2 x 4 with two sources (decanted phosphate and monoammonium phosphate) and four doses of phosphorus (0, 80, 120, 160 kg ha -1 P 2 O 5 ). At 120 days after planting leaves were collected for analysis (leaf +1). At 120 and 240 days after planting measured and recorded abaxial epidermal thickness, adaxial epidermis thickness, mesophyll thickness, and phloematic vessel diameter. At 362 days after planting the stalk were harvested the whole plant of sugarcane, in total area of the plots for the determination of green forage mass (t ha -1 ). Phosphorus fertilization in pre-planting showed a positive response for the production of green forage mass, regardless of the sources used. The best responses were achieved at doses from 120 kg P 2 O 5 ha -1 . The nutritional condition of the plant was not influenced by sources and levels of phosphorus. Doses of phosphorus influenced the development of leaves conducting vessels of sugar cane at harvest. Doses above 120 kg P 2 O 5 ha -1 significantly increases the ATR (t ha -1 ), which did not occur with fiber (%), brix (%) POL (%), purity (%) and ATR (kg t -1 ). The sources and doses of phosphorus tested improved the soil chemical properties. The decanted phosphate can replace the monoammonium phosphate fertilization in pre-planting of sugarcane / Mestre

Este estudo visou quantificar os teores de fosfato total, inorgânico e orgânico no caldo proveniente de diferentes alturas (região basal, mediana e apical) do colmo de três variedades de cana-de-açúcar, além de buscar levantar a ocorrência de myo-inositol hexafosfato (ácido fítico) em colmos de cana-de-açúcar. A composição química e tecnológica de colmos de cana-de-açúcar está relacionada com as características genéticas da variedade. Os colmos da cana-de-açúcar são compostos de fibra e caldo absoluto. O caldo contém cerca de 25% de sólidos solúveis, dos quais a sacarose se destaca. Na área agrícola o elemento fósforo é importante principalmente no metabolismo fotossintético da planta. No caldo de cana-de-açúcar se encontra nas formas mineral e orgânica, exercendo uma função chave no processo de clarificação do caldo para produção de açúcar, sendo também importante nos processos de fermentação alcoólica. Em grãos de cereais e leguminosas, estudos com o elemento fósforo, ou mais especificamente o myo-inositol hexafosfato (ácido fítico), têm mostrado algumas características antinutricionais, antioxidantes e anticarcinogênicas, que o ácido fítico possui quando complexado com certos cátions. Foram utilizadas as variedades SP 82-3530, SP 83-5073 e RB 83-5486 de cana-de-açúcar para as análises de fosfatos, sendo os colmos das mesmas divididos em região basal (3/8), mediana (3/8) e apical (2/8). Para as análises de ácido fítico foi utilizada apenas a variedade SP 82-3530, sendo os colmos desta analisados integralmente, com e sem casca, e divididos em nós e internódios com e sem casca. O caldo dos colmos de cana foi extraído em prensa hidráulica. As variedades apresentaram teores que variaram de 370 a 936 mg P2O5 total por litro de caldo. As regiões do colmo apresentaram valores decrescentes para os três tipos de fosfato da base para o ápice do colmo. O fosfato orgânico representou aproximadamente 5% do total. As porcentagens dos teores de fosfato orgânico em relação ao total, apresentaram um gradiente crescente da região basal para a apical. A análise de ácido fítico, por este ter apresentado teores insignificantes no caldo e na cana, ficou prejudicada pela metodologia aplicada, a qual se mostrou inadequada. / The objective of the present study was to estimate total, inorganic and organic phosphate amounts in the juice of stalk segments (basal, middle and top) of three sugarcane varieties, as well as assessing the presence of myo-inositol 6-phosphate (phytic acid) in sugarcane stalks. The chemical and technological compositions of sugarcane stalks are linked to the genetic characteristics of each variety. Sugarcane stalks are composed of fiber and absolute juice. The juice contains about 25% of soluble solids, mainly sucrose. Phosphorus is an important element in agriculture, due to its participation in the photosynthetic metabolism of plants. Phosphorus is found in its mineral and organic forms in the sugarcane juice and plays a key role in the clarification and fermentation processes for the production of sugar and alcohol. Studies on phosphorus, or rather, on myo-inositol 6-phosphate (phytic acid), in cereal and leguminous grains have evidenced some anti-nutritious, antioxidant and anticarcinogenic characteristics of the phytic acid when complexed with certain cations. Basal (3/8), middle (3/8) and top (2/8) stalk segments from SP 82-3530, SP 83-5073 and RB 83-5486 sugarcane varieties were analyzed for their phosphate amounts. Only stalk segments from the variety SP 82-3530, separated in nodes and internodes, peeled or not, were analyzed for phytic acid amounts. The juice of sugarcane stalks was extracted on hydraulic press. Total P2O5 varied from 370 to 936 mg per liter of juice. The three types of phosphate showed decreasing amounts from the bottom to the top of the stalk. Organic phosphate constituted approximately 5% of total phosphate. Percentages of organic phosphate in relation to total phosphate amounts increased gradually from the basal to the top stalk segments. As phytic acid was found in insignificant amounts, the assessment of its presence was limited by the methodology used, which showed to be inappropriate.

Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

An investigation has been made of the role of the four disulfide bonds of bovine pancreatic ribonuclease in maintaining the protein in a biologically active form. Studies were carried out to determine the effect of reductive cleavage of these bonds on the ability of the enzyme to catalyze the hydrolysis of ribonucleic acid. The appearance of sulfhydryl groups was taken as evidence that reduction of the protein had occurred. <P> No significant reduction or loss of enzymic activity of ribonuclease could be demonstrated when the protein was treated with the reducing agents sodium or potassium borohydride in aqueous solution at room temperature,pH 8. <P> Thioglycolic acid was found to be an effective agent for reducing ribonuclease disulfide bonds. At room temperature, in an aqueous solution containing a Large excess of thioglycolate over protein, reduction proceeded slowly at pH 8. At the end of five hours, approximately one disulfide bond was broken, with the loss of 20 per cent of the original enzyme activity. The addition of urea greatly facilitated reduction. The rate of reduction was especially rapid in solutions of urea concentration greater than 4 molar. In 8 M urea at pH 8, treatment of ribonuclease with thioglycolate resulted in the complete loss of enzymic activity in one half hour, with the simultaneous rupture of two or three disulfide bonds. Under these conditions, maximum reduction was achieved in approximately two hours, with cleavage of between three and four disulfide bonds per molecule. In the pH range from 3 to 10, rate of activity loss was most rapid at pH 10, slightly less rapid at pH 3, and reached a minimum near pH 5. The effects of pH and urea were additive in that the maximum rate of inactivation occurred at pH 10 in 8 M urea (97 per cent activity loss in 10 minutes), and the minimum rate st pH 5 in the absence of urea (20 per cent loss in 28 hours). <P> Inactivation was markedly inhibited by phosphate ions. A solution of protein which was O.36 M in phosphate at pH 8 lost activity very slowly when treated with thioglycolic acid, even in the presence of 4 M urea. These findings, together with the observation of other workers that polyvalent ions such as phosphate reverse the denaturetion of ribonuclease in urea, suggest that phosphate inhibits reduction by stabilizing the protein in its native configuration, whereas urea facilitates reduction by denaturing the protein. <P> Air oxidation of fully or partially inactivated protein resulted, in some cases, in the recovery of up to 4O per cent of the enzyme activity which had been lost as a result of reduction. <P> The relation between loss of activity and reduction was analyzed by correlating the data obtained in those experiments in which both the sulfhydryl concentration and the enzymic activity of samples of modified protein were determined. The experiments were carried out under a variety of conditions of pH and urea concentration. On the basis of these data, it is concluded that the inactivation of thioglycolate-treated ribonuclease is probably not a unique function of extent of reduction, but depends in part on the method by which the reduction is achieved.

Thèse de doctorat : Spectrochimie, molécules, solides, réactivité : Lille 1 : 2001. / Résumé en français et en anglais. Bibliogr. en fin de chapitres.

Reproduction de : Thèse d'exercice : Pharmacie : Nantes : 2009. / Bibliogr.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: factor; FGF-23; phosphatonin; microarray; expression; phosphate; time; gene; RT-PCR; growth; fibroblast. Includes bibliographical references (p. 127-136).

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