Structure-based drug design and combinatorial chemistry play important roles in the search for new drugs, and both these elements of medicinal chemistry were included in the present studies. This thesis outlines the synthesis of protease inhibitors against thrombin and the HCV NS3 protease, as well as the synthesis of a combinatorial library using solid phase chemistry.In the current work potent thrombin inhibitors were generated based on the D-Phe-Pro-Arg motif incorporating cyclopentene and cyclohexene scaffolds that were synthesized by ring-closing metathesis chemistry. A structure-activity relationship study was carried out using the crystallographic results for one of the inhibitors co-crystallized with thrombin. HCV NS3 protease inhibitors comprising the proline bioisostere 4-hydroxy-cyclopent-2-ene-1,2-dicarbboxylic acid were synthesized displaying low nanomolar activity. The stereochemistry and regiochemistry of the scaffolds were determined by NOESY and HMBC spectra, respectively. The final diastereomeric target compounds were isolated and annotated by applying TOCSY and ROESY NMR experiments. Furthermore, a 4-phenyl-2-carboxypiperazine targeted combinatorial chemistry library was synthesized to be used early in the lead discovery phase. This was done using a scaffold that was synthesized by palladiumcatalyzed aromatic amination chemistry and subsequently derivatized with eight electrophiles and ten nucleophiles.

The thiopyran route to polypropionates is an attractive strategy that involves a stepwise iterative aldol homologation of tetrahydro-4H-thiopyran-4-one (I) with thiopyran aldehyde (II) followed by desulfurization to rapidly assemble stereochemically complex polypropionate synthons. <p>In chapter 1, the thesis is summarized in the context of relevant background research including; a) the basic principle of the thiopyran route; b) dynamic kinetic resolution of -substituted aldehydes; c) previous syntheses of serricornin; iv) previous syntheses of membrenones.<p>In chapter 2, proline-catalyzed enantioselective direct intermolecular aldol reactions of tetrahydro-4H-thiopyran-4-one with various achiral aldehydes were studied. The results provided insights on the behaviour and stereoselectivity profile of thiopyranone (a crucial starting block in the thiopyran design) in the proline-catalyzed aldol reaction.<p>In chapter 3, inspired by the results of the aldol reaction of ketone (I) with achiral aldehydes, we next investigated the proline-catalyzed asymmetric aldol reactions of (I) with racemic thiopyran aldehyde (II) as a strategy to rapidly prepare enantiomerically pure tetrapropionate synthons without any requirement of enantioenriched aldehyde. The reaction occurred with high enantiotopic group selectivity and dynamic kinetic resolution.<p>In chapter 4, a detailed study to ascertain the scope and limitations of the design strategy described in chapter 3 was extended towards other catalysts, aldehydes and ketones. <p>Finally, applications of the above mentioned strategy towards the synthesis of serricornin and membrenones A and B are elaborated in chapters 5 and 6 respectively.

The thiopyran route to polypropionates is an attractive strategy that involves a stepwise iterative aldol homologation of tetrahydro-4H-thiopyran-4-one (I) with thiopyran aldehyde (II) followed by desulfurization to rapidly assemble stereochemically complex polypropionate synthons. <p>In chapter 1, the thesis is summarized in the context of relevant background research including; a) the basic principle of the thiopyran route; b) dynamic kinetic resolution of -substituted aldehydes; c) previous syntheses of serricornin; iv) previous syntheses of membrenones.<p>In chapter 2, proline-catalyzed enantioselective direct intermolecular aldol reactions of tetrahydro-4H-thiopyran-4-one with various achiral aldehydes were studied. The results provided insights on the behaviour and stereoselectivity profile of thiopyranone (a crucial starting block in the thiopyran design) in the proline-catalyzed aldol reaction.<p>In chapter 3, inspired by the results of the aldol reaction of ketone (I) with achiral aldehydes, we next investigated the proline-catalyzed asymmetric aldol reactions of (I) with racemic thiopyran aldehyde (II) as a strategy to rapidly prepare enantiomerically pure tetrapropionate synthons without any requirement of enantioenriched aldehyde. The reaction occurred with high enantiotopic group selectivity and dynamic kinetic resolution.<p>In chapter 4, a detailed study to ascertain the scope and limitations of the design strategy described in chapter 3 was extended towards other catalysts, aldehydes and ketones. <p>Finally, applications of the above mentioned strategy towards the synthesis of serricornin and membrenones A and B are elaborated in chapters 5 and 6 respectively.

Reproduction de : Thèse de doctorat : Stratégie d'exploitation des fonctions biologiques : Lille 1 : 2004. / Résumé en français et en anglais. Titre provenant de la page de titre du document numérisé. Bibliogr. f. 107-123.

Small proline-rich protein-2 (SPRR2) functions as a determinant of flexibility and permeability in the mature cornified envelope of the skin. SPRR2 is strongly upregulated by the commensal flora and may mediate signaling to differentiated epithelia of the small intestine and colon. Yet, SPRR2 function in the GI tract is largely unexplored. Using the Caco-2 model of intestinal epithelial differentiation along the crypt-villus axis, we hypothesized that SPRR2 would be preferentially expressed in post-confluent differentiated Caco-2 cells and examined SPRR2 regulation by the protein kinase A pathway (PKA) and short chain fatty acids (SCFAs). Differentiation-dependent SPRR2 expression was examined in cytoskeletal-, membrane-, and nuclear-enriched fractions by immunoblotting and confocal immunofluorescence. We studied the effect of SCFAs, known inducers of differentiation, on SPRR2 expression in pre-confluent undifferentiated Caco-2 cells and explored potential mechanisms involved in this induction using MAP kinase inhibitors. SPRR2 expression was also compared between HIEC crypt cells and 16 to 20 week primary fetal villus cells as well as in different segments in mouse small intestine and colon. We determined if SPRR2 is increased by gram negative bacteria such as S. typhimurium. SPRR2 expression increased in a differentiation-dependent manner in Caco-2 cells and was present in human fetal epithelial villus cells but absent in HIEC crypt cells. Differentiation-induced SPRR2 was down-regulated by 8-Br-cAMP as well as by forskolin/IBMX co-treatment. SPRR2 was predominantly cytoplasmic and did not accumulate in Triton X-100-insoluble cytoskeletal fractions. SPRR2 was present in the membrane- and nuclear-enriched fractions and demonstrated co-localization with F-actin at the apical actin ring. No induction was seen with the specific HDAC inhibitor trichostatin A, while SCFAs and the HDAC inhibitor SBHA all induced SPRR2. SCFA responses were inhibited by MAP kinase inhibitors SB203580 and U0126, thus suggesting that the SCFA effect may be mediated by orphan G-protein receptors GPR41 and GPR43. S. typhimurium induced SPRR2 in undifferentiated cells. We conclude that SPRR2 protein expression is associated with differentiated epithelia and is regulated by PKA signaling and by by-products of the bowel flora. This is the first report to establish an in vitro model to study the physiology and regulation of SPRR2. / Thesis (Master, Anatomy & Cell Biology) -- Queen's University, 2008-04-25 12:39:06.427 / This work was funded by the CIHR GIDRU Training Grant and Aid in Research from Crohn's and Colitis Foundation of Canada

Ce travail de thèse porte dans un premier temps sur la synthèse de nouveaux sels d'azolinium chiraux précurseurs de carbènes N-hétérocycliques. Deux nouvelles familles de sels ont été préparées à partir de la L-proline. Nous avons pu caractériser les NHC issus de ces sels, par la formation des dimères, des thiones et des complexes de rhodium correspondants. Dans un second temps, ces nouveaux sels d'azolinium ont été évalués dans la réaction d'addition conjuguée de réactifs de Grignard sur des cétones α,β insaturées. Les résultats ont montré de très bonnes activités catalytiques, et de très bonnes régiosélectivités. Les énantiosélectivités obtenues sont encourageantes. Ensuite, ces catalyseurs ont été engagés dans la réaction de substitution allylique. Une bonne activité catalytique a aussi été observée malgré des régiosélectivités et des énantiosélectivités modérées. Enfin, ces sels ont été employés comme précurseurs de NHC pour la réduction asymétrique de cétones aromatiques par transfert d'hydrogène. Les complexes formés se sont montrés actifs mais non énantiosélectifs.

ABSTRACT EFFECT OF SALT STRESS ON ANTIOXIDANT DEFENSE SYSTEMS OF SENSITIVE AND RESISTANT CULTIVARS OF LENTIL Cicerali, Iin Nur M.Sc., Department of Biotechnology Supervisor: Prof. Dr. Meral Y&uuml / cel Co-supervisor: Asst. Prof. Dr. F&uuml / sun (nci) Eyidoan June 2004, 90 pages In this study, two lentil cultivars (Lens culinaris, Medik.) (ILL5582-salt tolerant and ILL590) were characterized and compared due to their NaCl susceptibility and antioxidant mechanism was examined under laboratory conditions. Physiological parameters such as wet-dry weight, root-shoot lengths, cell membrane stability, lipid peroxidation in terms of malondialdehyde (MDA), H2O2, proline contents were determined. The activities of antioxidant enzymes such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11) and glutathione reductase (GR: EC 1.6.4.2) were examined and analyzed in 14 days old plant seedlings after 9 days of normal growth and 5 days of 100mM and 200mM NaCl stress conditions. Shoot-root length and wet-dry weight percent decrease were more in ILL590. Especially shoot tissues were affected more from the stress conditions when compared to root tissues. ii According to malondialdehyde (MDA) content and membrane stability results, lipid peoxidation was higher in ILL590 and significant increases were observed in shoot tissues. Proline concentration showed a remarkable increase in salt concentration dependent manner. Higher concentrations of proline in ILL5582 might be the reason of higher salt tolerance when compared to ILL590. Among the antioxidant enzymes SOD was the one which showed highest activity increase. At organ level roots showed highest activity when compared to leaves. In the organelle higher activity percent contribution was achieved by cytosolic Cu/ZnSOD isozyme. Higher percent increase of this isozyme was observed in ILL5582. This might be one of the tolerance mechanisms that get activated against NaCl stress. APX activity showed similar alterations in both cultivars. In leaf tissues significant increase was observed but in root tissues ascorbate peroxidase activity did not change significantly. Glutathione Reductase activity increase was significant in both cultivars leaf tissues but although ILL5582 showed a stress concentration dependent increase, ILL590 did not. The activity of CAT enzyme in leaf and root tissues of both cultivars did not significantly change under increasing salt stress conditions. The results suggested that the leaves were more susceptible to salt stress. Also when two cultivars were compared ILL5582 was found to be more tolerant against salt stress than ILL590 under laboratory conditions and SOD enzyme seemed to be the most active component of the salt tolerant mechanism.

FREITAS, Paulo André Ferreira de. Aplicação foliar de prolina como meio de minorar os efeitos do estresse salino em plantas de milho. 2013. 109 f. : Dissertação (Mestrado em Bioquímica) - Universidade Federal do Ceará, Fortaleza-CE, 2013. / Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-06-27T13:45:35Z No. of bitstreams: 1 2013_dis_paffreitas.pdf: 2578027 bytes, checksum: 526a18fbbfe45aa94b6e45cddcd5dec7 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T20:09:09Z (GMT) No. of bitstreams: 1 2013_dis_paffreitas.pdf: 2578027 bytes, checksum: 526a18fbbfe45aa94b6e45cddcd5dec7 (MD5) / Made available in DSpace on 2016-08-02T20:09:09Z (GMT). No. of bitstreams: 1 2013_dis_paffreitas.pdf: 2578027 bytes, checksum: 526a18fbbfe45aa94b6e45cddcd5dec7 (MD5) Previous issue date: 2013 / The present study aimed to evaluate the influence of foliar application of proline in growth and development of maize plants under saline conditions, analyzing physiological and biochemical alterations involved. Seeds of maize (Zea mays) genotype BR 205, being carried two experiments in greenhouse. At first experiment, we evaluated the physiological and biochemical responses in maize plants under saline conditions and subjected to foliar application of proline. For this, the maize plants with 10 days old growing in individual buckets with 10 L, containing nutrient solution of Clark. Four treatments were conducted: 1. plants growing in nutrient solution and leaves sprayed with distilled water, 2. plants growing in nutrient solution and leaves sprayed with 30 mM proline 3.plants growing in nutrient solution containing 80 mM of NaCl and leaves sprayed with distilled water, and 4. plants growing in nutrient solution containing 80 mM NaCl and leaves sprayed with 30 mM proline. The experimental design was completely randomized, with two levels of proline (0 or 30 mM), two levels of salinity (0 or 80 mM NaCl) and two haverst times (plants 7 and 14 days after treatment application. ) with six replications. In this experiment, plants were collected at 7 and 14 days after the imposition of the treatments, the plants were separated into leaves, stems and sheath and roots. Were analyzed: dried weight of shoots, roots and whole plant, leaf area, concentrations of inorganic solutes (Na+, K+ and Cl-) and organic (soluble carbohydrates, soluble proteins, N-aminosolubles and proline). As result, it was found that the foliar application of proline itself had no effect on the growth of maize plants. However, in saline conditions, such treatment was effective in alleviating the reduction in growth by salinity. This was due, in part, by lower accumulation of toxic ions (Na+ and Cl-), mainly in shoot, combined with a smaller reduction in K+/Na+ plants treated with exogenous proline. Treatment with proline reversed the reduction in soluble protein content by salinity in shoots, roots while these levels were increased to levels higher than those of the controls themselves. The soluble carbohydrates and proline have been changed in different ways by treatment with proline, depending on the organ examined. The second experiment was conducted under similar conditions to the first and following the same treatments and experimental design. The objective was to evaluate the effect of foliar application of proline 30 mM in gas exchange, the levels of malondialdehyde and H2O2, and the activities of protection enzyme system and oxidative metabolism of proline in leaves and roots of maize plants under saline conditions. Salinity reduced gas exchange and exogenous proline caused no changes in these parameters, except for a small increase in the rate of transpiration. In leaves and roots, salinity increased the levels of H2O2 and malondialdehyde, both effects being partially reduced by foliar application of proline in maize plants. This treatment increased the activities of the enzymes superoxide dismutase and catalase, this last especially in leaves, having reversed its reduction in activity by salinity and possibly this may have contributed to the reduction of the levels of H2O2 and malondialdehyde, an indicator reliable membrane damage. Moreover, the study on the enzymes of the metabolism of proline was observed in leaves, which activity Δ1-pyrroline-5-carboxylate synthase (P5CS), enzyme of proline anabolic pathway, had increased his activity by salinity, but the treatment with exogenous proline strongly reduced its activity after 14 days of treatment. Already proline dehydrogenase (PDH), the enzyme proline catabolic pathway, was strongly stimulated by exogenous proline, under control or salt stress, which suggests that this enzyme is induced by excess proline in tissues. The role of these enzymes in tissue levels of proline could not be clearly established, since the response pattern in their activities by treatment with exogenous proline was not consistent between the two haverst times for maize. / O presente trabalho, teve por objetivo avaliar a influência da aplicação foliar de prolina no crescimento e desenvolvimento das plantas de milho, sob condições de salinidade, analisando as alterações fisiológicas e bioquímicas envolvidas. Foram utilizadas sementes de milho (Zea mays), genótipo BR 205, sendo realizados dois experimentos em casa de vegetação. No primeiro, foram avaliadas as respostas fisiológicas e bioquímicas em plantas de milho, sob condições de salinidade e submetidas à aplicação foliar de prolina. Para isso, plantas de milho com 10 dias de idade crescendo em baldes plásticos individuais de 10 L, contendo solução nutritiva de Clarck, foram distribuídas em quatro tratamentos: 1. plantas crescendo em solução nutritiva e pulverizadas nas folhas com água destilada; 2. plantas crescendo em solução nutritiva e pulverizadas nas folhas com prolina a 30 mM; 3. plantas crescendo em solução nutritiva contendo NaCl a 80 mM e pulverizadas nas folhas com água destilada; e 4. plantas crescendo em solução nutritiva contendo NaCl a 80 mM e pulverizadas nas folhas com prolina a 30 mM. O delineamento experimental foi o inteiramente casualizado, com dois níveis de prolina (0 ou 30 mM), dois níveis de salinidade (0 ou 80 mM de NaCl) e dois tempos de coleta (plantas com 7 e 14 dias após a aplicação dos tratamentos.), com seis repetições. Nesse experimento, foram coletadas plantas aos 7 e 14 dias após a imposição dos tratamentos, sendo as plantas separadas em folhas, colmos + bainha e raízes. Foram analisadas: as massas secas da parte aérea, raízes e da planta inteira; a área foliar; os teores de solutos inorgânicos (Na+, K+ e Cl-) e orgânicos (carboidratos solúveis, proteínas solúveis, N-aminossolúveis e prolina). Como resultado, observou-se que a aplicação foliar de prolina, por si só, não causou efeito no crescimento das plantas de milho. Entretanto, em condições salinas, tal tratamento foi eficaz em minorar a redução no crescimento pela salinidade. Isso se deveu, em parte, pelo menor acúmulo de íons tóxicos (Na+ e Cl-), principalmente na parte aérea, aliado a uma menor redução na relação K+/Na+ das plantas tratadas com prolina exógena. O tratamento com prolina reverteu à redução nos teores de proteínas solúveis pela salinidade, na parte aérea, enquanto nas raízes esses teores foram aumentados a níveis maiores do que os dos próprios controles. Os teores de carboidratos solúveis e de prolina foram alterados de formas diferentes pelo tratamento com prolina, dependendo do órgão analisado. O segundo experimento foi realizado em condições semelhantes às do primeiro e seguindo-se os mesmos tratamentos e delineamento experimental. Ele teve como finalidade avaliar os efeitos da aplicação foliar de prolina a 30 mM nas trocas gasosas, nos teores de malondialdeído e de H2O2, e nas atividades das enzimas do sistema de proteção oxidativa e do metabolismo da prolina, em folhas e raízes de plantas de milho sob condições de salinidade. A salinidade reduziu as trocas gasosas e a prolina exógena não provocou alterações nesses parâmetros, exceto por uma pequena elevação na taxa de transpiração. Nas folhas e raízes, a salinidade aumentou os teores de H2O2 e de malondialdeído, sendo ambos os efeitos parcialmente reduzidos pela aplicação foliar de prolina nas plantas de milho. Esse tratamento aumentou as atividades das enzimas dismutase do superóxido e catalase, especialmente dessa última nas folhas, tendo revertido sua redução em atividade pela salinidade e, possivelmente, isso pode ter contribuído para a redução dos teores de H2O2 e de malondialdeído, que é um indicador confiável de danos de membrana. Por outro lado, no estudo sobre as enzimas do metabolismo da prolina, observou-se, nas folhas, que a atividade da sintetase da Δ1-pirrolina-5-carboxilato (P5CS), enzima da via de síntese da prolina, teve sua atividade aumentada pela salinidade, porém o tratamento com prolina exógena reduziu fortemente sua atividade aos 14 dias de tratamento. Já a prolina desidrogenase (PDH), enzima da via catabólica da prolina, foi fortemente estimulada pela prolina exógena, em condições controle ou de estresse salino, fato que sugere que essa enzima é induzida pelo excesso de prolina nos tecidos. O papel dessas enzimas nos níveis de prolina dos tecidos não pôde ser claramente estabelecido, desde que o padrão de resposta em suas atividades pelo tratamento com prolina exógena não foi consistente entre os dois tempos de coleta das plantas de milho.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O presente trabalho, teve por objetivo avaliar a influÃncia da aplicaÃÃo foliar de prolina no crescimento e desenvolvimento das plantas de milho, sob condiÃÃes de salinidade, analisando as alteraÃÃes fisiolÃgicas e bioquÃmicas envolvidas. Foram utilizadas sementes de milho (Zea mays), genÃtipo BR 205, sendo realizados dois experimentos em casa de vegetaÃÃo. No primeiro, foram avaliadas as respostas fisiolÃgicas e bioquÃmicas em plantas de milho, sob condiÃÃes de salinidade e submetidas à aplicaÃÃo foliar de prolina. Para isso, plantas de milho com 10 dias de idade crescendo em baldes plÃsticos individuais de 10 L, contendo soluÃÃo nutritiva de Clarck, foram distribuÃdas em quatro tratamentos: 1. plantas crescendo em soluÃÃo nutritiva e pulverizadas nas folhas com Ãgua destilada; 2. plantas crescendo em soluÃÃo nutritiva e pulverizadas nas folhas com prolina a 30 mM; 3. plantas crescendo em soluÃÃo nutritiva contendo NaCl a 80 mM e pulverizadas nas folhas com Ãgua destilada; e 4. plantas crescendo em soluÃÃo nutritiva contendo NaCl a 80 mM e pulverizadas nas folhas com prolina a 30 mM. O delineamento experimental foi o inteiramente casualizado, com dois nÃveis de prolina (0 ou 30 mM), dois nÃveis de salinidade (0 ou 80 mM de NaCl) e dois tempos de coleta (plantas com 7 e 14 dias apÃs a aplicaÃÃo dos tratamentos.), com seis repetiÃÃes. Nesse experimento, foram coletadas plantas aos 7 e 14 dias apÃs a imposiÃÃo dos tratamentos, sendo as plantas separadas em folhas, colmos + bainha e raÃzes. Foram analisadas: as massas secas da parte aÃrea, raÃzes e da planta inteira; a Ãrea foliar; os teores de solutos inorgÃnicos (Na+, K+ e Cl-) e orgÃnicos (carboidratos solÃveis, proteÃnas solÃveis, N-aminossolÃveis e prolina). Como resultado, observou-se que a aplicaÃÃo foliar de prolina, por si sÃ, nÃo causou efeito no crescimento das plantas de milho. Entretanto, em condiÃÃes salinas, tal tratamento foi eficaz em minorar a reduÃÃo no crescimento pela salinidade. Isso se deveu, em parte, pelo menor acÃmulo de Ãons tÃxicos (Na+ e Cl-), principalmente na parte aÃrea, aliado a uma menor reduÃÃo na relaÃÃo K+/Na+ das plantas tratadas com prolina exÃgena. O tratamento com prolina reverteu à reduÃÃo nos teores de proteÃnas solÃveis pela salinidade, na parte aÃrea, enquanto nas raÃzes esses teores foram aumentados a nÃveis maiores do que os dos prÃprios controles. Os teores de carboidratos solÃveis e de prolina foram alterados de formas diferentes pelo tratamento com prolina, dependendo do ÃrgÃo analisado. O segundo experimento foi realizado em condiÃÃes semelhantes Ãs do primeiro e seguindo-se os mesmos tratamentos e delineamento experimental. Ele teve como finalidade avaliar os efeitos da aplicaÃÃo foliar de prolina a 30 mM nas trocas gasosas, nos teores de malondialdeÃdo e de H2O2, e nas atividades das enzimas do sistema de proteÃÃo oxidativa e do metabolismo da prolina, em folhas e raÃzes de plantas de milho sob condiÃÃes de salinidade. A salinidade reduziu as trocas gasosas e a prolina exÃgena nÃo provocou alteraÃÃes nesses parÃmetros, exceto por uma pequena elevaÃÃo na taxa de transpiraÃÃo. Nas folhas e raÃzes, a salinidade aumentou os teores de H2O2 e de malondialdeÃdo, sendo ambos os efeitos parcialmente reduzidos pela aplicaÃÃo foliar de prolina nas plantas de milho. Esse tratamento aumentou as atividades das enzimas dismutase do superÃxido e catalase, especialmente dessa Ãltima nas folhas, tendo revertido sua reduÃÃo em atividade pela salinidade e, possivelmente, isso pode ter contribuÃdo para a reduÃÃo dos teores de H2O2 e de malondialdeÃdo, que à um indicador confiÃvel de danos de membrana. Por outro lado, no estudo sobre as enzimas do metabolismo da prolina, observou-se, nas folhas, que a atividade da sintetase da &#916;1-pirrolina-5-carboxilato (P5CS), enzima da via de sÃntese da prolina, teve sua atividade aumentada pela salinidade, porÃm o tratamento com prolina exÃgena reduziu fortemente sua atividade aos 14 dias de tratamento. Jà a prolina desidrogenase (PDH), enzima da via catabÃlica da prolina, foi fortemente estimulada pela prolina exÃgena, em condiÃÃes controle ou de estresse salino, fato que sugere que essa enzima à induzida pelo excesso de prolina nos tecidos. O papel dessas enzimas nos nÃveis de prolina dos tecidos nÃo pÃde ser claramente estabelecido, desde que o padrÃo de resposta em suas atividades pelo tratamento com prolina exÃgena nÃo foi consistente entre os dois tempos de coleta das plantas de milho. / The present study aimed to evaluate the influence of foliar application of proline in growth and development of maize plants under saline conditions, analyzing physiological and biochemical alterations involved. Seeds of maize (Zea mays) genotype BR 205, being carried two experiments in greenhouse. At first experiment, we evaluated the physiological and biochemical responses in maize plants under saline conditions and subjected to foliar application of proline. For this, the maize plants with 10 days old growing in individual buckets with 10 L, containing nutrient solution of Clark. Four treatments were conducted: 1. plants growing in nutrient solution and leaves sprayed with distilled water, 2. plants growing in nutrient solution and leaves sprayed with 30 mM proline 3.plants growing in nutrient solution containing 80 mM of NaCl and leaves sprayed with distilled water, and 4. plants growing in nutrient solution containing 80 mM NaCl and leaves sprayed with 30 mM proline. The experimental design was completely randomized, with two levels of proline (0 or 30 mM), two levels of salinity (0 or 80 mM NaCl) and two haverst times (plants 7 and 14 days after treatment application. ) with six replications. In this experiment, plants were collected at 7 and 14 days after the imposition of the treatments, the plants were separated into leaves, stems and sheath and roots. Were analyzed: dried weight of shoots, roots and whole plant, leaf area, concentrations of inorganic solutes (Na+, K+ and Cl-) and organic (soluble carbohydrates, soluble proteins, N-aminosolubles and proline). As result, it was found that the foliar application of proline itself had no effect on the growth of maize plants. However, in saline conditions, such treatment was effective in alleviating the reduction in growth by salinity. This was due, in part, by lower accumulation of toxic ions (Na+ and Cl-), mainly in shoot, combined with a smaller reduction in K+/Na+ plants treated with exogenous proline. Treatment with proline reversed the reduction in soluble protein content by salinity in shoots, roots while these levels were increased to levels higher than those of the controls themselves. The soluble carbohydrates and proline have been changed in different ways by treatment with proline, depending on the organ examined. The second experiment was conducted under similar conditions to the first and following the same treatments and experimental design. The objective was to evaluate the effect of foliar application of proline 30 mM in gas exchange, the levels of malondialdehyde and H2O2, and the activities of protection enzyme system and oxidative metabolism of proline in leaves and roots of maize plants under saline conditions. Salinity reduced gas exchange and exogenous proline caused no changes in these parameters, except for a small increase in the rate of transpiration. In leaves and roots, salinity increased the levels of H2O2 and malondialdehyde, both effects being partially reduced by foliar application of proline in maize plants. This treatment increased the activities of the enzymes superoxide dismutase and catalase, this last especially in leaves, having reversed its reduction in activity by salinity and possibly this may have contributed to the reduction of the levels of H2O2 and malondialdehyde, an indicator reliable membrane damage. Moreover, the study on the enzymes of the metabolism of proline was observed in leaves, which activity &#916;1-pyrroline-5-carboxylate synthase (P5CS), enzyme of proline anabolic pathway, had increased his activity by salinity, but the treatment with exogenous proline strongly reduced its activity after 14 days of treatment. Already proline dehydrogenase (PDH), the enzyme proline catabolic pathway, was strongly stimulated by exogenous proline, under control or salt stress, which suggests that this enzyme is induced by excess proline in tissues. The role of these enzymes in tissue levels of proline could not be clearly established, since the response pattern in their activities by treatment with exogenous proline was not consistent between the two haverst times for maize.

Sugarcane is a C4 plant that can be grown in tropical and subtropical regions adapt to different soil types and climatic conditions, especially for its large and broad utility operation, and raw material for various products such as molasses, molasses, sugar and ethanol. However, the production of cane sugar is being affected by poor rainfall distribution and the reduction of presipitation in some regions. Thus, this study aimed to characterize (field capacity) and evaluate the performance of genotypes of sugar cane submitted to water restriction and rehydration, using physiological indicators. The study was conducted in two experiments conducted at the Department of Agricultural Engineering, Federal University of Sergipe (UFS) in the municipality of São Cristovão - SE. The seedlings used for both studies were transplanted at 45 days for vessels of 18 dm3. The first experiment was performed to characterize the genotypes, in which they were carried out at field capacity, rated to 154 days after the transplan, between 10:30 and 12h00h, analyzing the variables: chlorophyll a fluorescence, content of chlorophyll a, be total levels of proline, water potential, transpiration, leaf temperature and air humidity, when the main plant, stem diameter, leaf number and leaf area. The experimental design was randomized blocks with four treatments (genotype 698B, 712B, 260B and 3B), four replications and one plant as a plot. In terms of field capacity 3B genotype showed the highest levels of chlorophyll a, b and total, Fv / Fm, height of main stem and leaf water potential, especially also in number of leaves and leaf area. In relation to transpiration, leaf temperature and diameter, no difference was observed between genotypes. To determine the physiological performance under water restriction was interrupted irrigation for 154 days, being rehydrated, the media showed that the genotypes leaves only +1 or +2 expanded with at least 20% of the leaf green. The evaluations were performed every five days, and analyzed the following parameters: chlorophyll fluorescence, chlorophyll content, a, b and total levels of proline, water potential, transpiration, leaf temperature and air humidity, height of stem principal, number of leaves and leaf area of the main plant, dry weight and fresh shoot and root system, these last being held at the end of the experiment. The evaluations were performed between 10:30 and 12:00. The experiment was a factorial 4 x 9 (genotype 698B, 712B, 260B and 3B-nine evaluations during periods of water restriction and rehydration), four replications and one plant as a useful parcel Fluid restriction induced a decrease for the variables analyzed in all genotypes, and the 3B and 698B were less tolerant, and rehydrated in 10 and 15 days restriction. Already 260B and 698B were more tolerant, where they were rehydrated in 25 days of restriction. It was also noted that during the restriction of proline accumulation obtained for all genotypes, whereas 698B and 3B showed higher values compared with the other. After rehydration of this amino acid was reduced in all genotypes, so that no significant differences. As to recovery after rehydration, the highlights were the genotypes 260B and 3B. In general, the 260B had the highest tolerance with higher results for the variables analyzed. / A Cana-de-açúcar é uma planta C4 que pode ser cultivada em regiões tropicais e subtropicais adaptando-se a diferentes tipos de solos e condições climáticas, destacando-se pela sua grande exploração e a ampla utilidade, sendo matéria prima para diversos produtos, como melaço, rapadura, açúcar e etanol. No entanto, a produção da cana-de-açúcar está sendo afetada pela má distribuição das chuvas e a redução da pressipitação em algumas regiões. Assim, o presente trabalho teve como objetivo caracterizar (capacidade de campo) e avaliar o desempenho de genótipos de cana-de-açúcar submetidos à restrição hídrica e reidratação, utilizando indicadores fisiológicos. O trabalho foi realizado em dois experimentos conduzido no Departamento de Engenharia Agronômica da Universidade Federal de Sergipe (UFS) localizada no município de São Cristóvão-SE. As mudas usadas para ambos os estudos, foram transplantadas aos 45 dias para vasos de 18 dm3. No primeiro experimento foi realizada a caracterização dos genótipos, em que os mesmos foram conduzidos em capacidade de campo, avaliados aos 154 dias após o transplatio, entre as 10h30min e as 12h00h, analisando as variáveis: fluorescência da clorofila a, teores de clorofila a, b e total, teores de prolina, potencial hídrico, transpiração, temperatura da folha e do ar, umidade relativa, altura da planta principal, diâmetro do colmo, número de folhas e área foliar. O delineamento experimental foi de blocos ao acaso, com quatro tratamentos (genótipos 698B, 712B, 260B e 3B), quatro repetições e uma planta como parcela útil. Em condições de capacidade de campo o genótipo 3B apresentou os maiores teores de clorofila a, b e total, de Fv/Fm, altura do colmo principal e potencial hídrico, destacando-se também em número de folha e área foliar. Em relação à transpiração, temperatura foliar e diâmetro, não foi observado diferença estatística entre os genótipos. Para a determinação do desempenho fisiológico sob restrição hídrica foi interrompida a irrigação aos 154 dias, sendo reidratadas a medida que os genótipos apresentavam apenas as folhas +1 ou +2 expandidas com no mínimo 20% do limbo foliar verde. As avaliações foram realizadas a cada cinco dias, sendo analisados os seguintes parâmetros: fluorescência da clorofila a, teores de clorofila a, b e total, teores de prolina, potencial hídrico, transpiração, temperatura da folha e do ar, umidade relativa, altura do colmo principal, número de folha e área foliar da planta principal, massa seca e fresca da parte aérea e do sistema radicular, sendo as duas ultimas realizadas no final do experimento. As avaliações foram realizadas entre as 10h30min e as 12h00min. O experimento foi realizado em esquema fatorial 4 x 9 (genótipo 698B, 712B, 260B e 3B e nove avaliações durante os períodos de restrição hídrica e reidratação), quatro repetições e uma planta como parcela útil. A restrição hídrica induziu um decréscimo para as variáveis analisadas em todos os genótipos, sendo que 3B e 698B foram menos tolerantes, sendo reidratadas no 10º e 15ºdia de restrição. Já 260B e 698B foram mais tolerantes, onde foram reidratadas no 25º dia de restrição. Também foi observado durante a restrição acúmulo de prolina em todos os genótipos, visto que o 698B e 3B apresentaram os maiores valores comparados com os demais. Após a reidratação houve redução deste aminoácido em todos os genótipos, de modo que não apresentaram diferenças significativas. Quanto à recuperação após a reidratação, destacaram-se os genótipos 260B e 3B. De maneira geral, 260B apresentou a maior tolerância apresentando os maiores resultados para as variáveis analisadas.