2009–2011 metais Lietuvos Žemės ūkio universiteto Bandymų stotyje, karbonatingame sekliai glėjiškame išplautžemyje (Calc(ar)i-Epihypogleyic Luvisols) IDg8-k (LVg-p-w-cc) atlikti tyrimai, siekiant įvertinti skirtingų žieminių kviečių veislių žiemkentiškumą. Fotosintezės pigmentų didžiausias kiekis nustatytas rudens-žiemos periodu, o pavasario pradžioje fotosintezės produktyvumas buvo mažiausias. Nustatyta, kad labai gerų kepimo sąvybių ’Ada’ linkusi kaupti didesnius fotosintezės pigmentų kiekius, lyginant su gerų kepimo savybių ’Tauras DS’. Didžiausias sacharidų kiekis (447,2 mg g-1) nustatytas lapkričio mėn. žieminiuose kviečiuose ’Tauras DS’ ir ’Ada’ (443,2 mg g-1), o nuo sausio mėn., nukritus lauko temperatūrai - sumažėjo iki 37,3–61,1 mg g-1 ’Tauras DS’ ir 128–80 mg g-1 ’Ada’ želmenyse. Ilgai trukę šalčiai sumažino tirpiųjų sacharidų kaupimąsi, jų kiekis padidėjo tik sumažėjus šalčiui. Tyrimo duomenys rodo, kad esant pastoviems žiemos šalčiams, sacharidų kiekis augaluose keitėsi nežymiai. Kadangi klimatinės sąlygos buvo vienodos, galima teigti, kad ’Ada’ veislės kviečiai kaupia didesnį kiekį sacharidų dėl veislės genetinių ypatumų. Tyrimo metu didesnius fenolinių junginių kiekius kaupė ’Tauras DS’ žieminiai kviečiai, todėl galime teigti, kad tai nulėmė veislės genetinės savybės. Nustatyta, kad ’Tauras DS’ kaupė didesnius prolino kiekius žemų temperatūrų poveikyje (gruodžio ir vasario mėnesiais – 1,65 μM g-1 ir 2,61 μM g-1 ) palyginus su žieminiais kviečiais ’Ada’... [toliau žr. visą tekstą] / The research was carried out in the Experimental Station of LUA. The aim of the research was to investigate and evaluate the frost resistence of different varieties of wheat. The soil ot the experimental site was (carbonaceous shallow Luvisols (Calc (or) i Epihypogleyic Luvisols) IDg8 k (LVD-pw-cc). The study revealed the maximum amount of photosyntthetic pigments in the autumn – winter period whereas in spring the photosyntthetic productivity was the lowest. It was found that ‚Ada‘ variety, having very good baking quality, tends to accumulate higher levels of photosyntthetic pigments than ‘Tauras DS‘ wheats with good baking properties. The highest amount of sugars was recorded in November in winter wheat ‘Tauras DS’ and ‘Ada’ (443,2 mg g-1), but the amount of sugars decreased significantly by 37,3–61,1 mg g-1 in ‘Tauras DS’ wheat and by 128–80 mg g-1 in ‘Ada’ wheat in January, as a result of a drop in temperature. The prolonged frosts reduced the accumulation of soluble sugars, moreover the amount of sugars increased only after the rise of temperature. The study shows the amount of sugars in plants is rather stable if there is no fluctuation in temperatures. Since the climatic conditions were stable we can state that the ‘Ada’ variety wheat accumulate bigger amounts of sugars because of its genetic characteristics. ‘Tauras DS’ variety demonstrated largers phenolic compounds due to its genetic characteristics. It was found that the ‘Tauras DS’ accumulated higher... [to full text]

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 3 uppsatser.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 149-157).

Dysregulation of endothelial cell barrier function is associated with a wide variety of human diseases ranging from tumor metastasis to inflammation. The barrier function of endothelial cells is maintained by cell adhesion molecules (CAMs). Immunoglobulin containing and proline-rich receptor-1(IGPR-1) was recently identified as a novel CAM involved in angiogenesis. However, the molecular mechanism of IGPR-1 function in endothelial cells remains largely unknown. The overarching goals of this study were: (A) to determine molecular mechanism by which IGPR-1 stimulates biological responses in cells and (B) to investigate regulation of phosphorylation of IGPR-1 at serine 220 (Ser220), and its role in IGPR-1 function. Our data demonstrate that IGPR-1 undergoes cis-dimerization, which leads to homophilic trans-dimerization of IGPR-1, which is required for its adhesive function. Moreover, we demonstrate that phosphorylation of Ser220 is regulated by trans-dimerization of IGPR-1 and that Glycogen Synthase Kinase 3 (GSK-3) is responsible for its phosphorylation as over-expression of kinase active increased and kinase inactive inhibited phosphorylation of Ser220, respectively. Taken together, the results demonstrate that the coordinated dimerization of IGPR-1 and its homophilic interaction regulates its adhesive function and serine phosphorylation. The adhesive function of IGPR-1 contributes to the barrier function of endothelial cells.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increasing demand for biofuels has provided significant increases in the areas of sugar cane in Brazil and in recent decades,and long periods of drought have limited the production of this species. This study aimed to evaluate the performance of cultivars RB 85-5536 and RB 93-509 of cane sugar on water restriction during the first stages of development. Experiment was carried out in the greenhouse of the Department of Agronomic Engineering at UFS in randomized blocks in factorial2 x 4, two cultivars (RB 85-5536 and RB 93-509) and four levels of water in the soil based on predefined at field capacity (100% Cc, 80% Cc, 60% Cc and 40% Cc), with four replications, each replicate consisting of a plant. Were evaluated the initial fluorescence emission (F0), maximum fluorescence (Fm), the quantum yield of photosystem (Fv/Fm) and fluorescence transient OJIP, indices of photosynthetic pigments and proline contents determined in leaves determined +1. The measurements of emission of fluorescence were performed during the period of seven days every two days, from 10 to 12 am, with the aid of fluorometer (OS-30P) and clips fixed on the central portion of the leaf, the contents of pigments were determined in the same period with the aidofaportable chlorophyllmeter (Clorofilog CFL 1030) whereas the proline content in the end of the experiment. The fluorescence emission levels and rates of photosynthetic pigments decreased with the increase of water restriction in both cultivars. The cultivar RB 93-509 has accumulated higher proline contentat the level of stress 60% of Cc. With the increase of stress severe by water restriction occurs a reduction in total levels of chlorophyll fluorescence and photosynthetic pigment contents from the seventh day of stress in both varieties of sugar cane. The cultivar RB 93-509 presents greater sensitivity to water stress than the cultivar RB 85-5536. / A crescente demanda por biocombustíveis tem proporcionado aumentos significativos das áreas de cana-de-açúcar no Brasil e nas últimas décadas os períodos prolongados de seca têm limitado a produção dessa espécie. Esse trabalho teve por objetivo avaliar o comportamento das cultivares RB 85-5536 e RB 93-509 de cana-deaçúcar quanto à restrição hídrica visando à seleção precoce. O experimento foi conduzido em casa de vegetação do Departamento de Engenharia Agronômica da UFS em delineamento experimental de blocos ao acaso em esquema fatorial 2 x 4, duas cultivares (RB 85- 5536 e RB 93-509) e quatros níveis de água no solo predefinidos com base na capacidade de campo (100% Cc, 80% Cc, 60% Cc e 40% Cc), com quatro repetições, sendo cada repetição constituída por uma planta. Foram avaliadas a emissão de fluorescência inicial (F0), fluorescência máxima (Fm), rendimento quântico do fotossistema (Fv/Fm) e fluorescência transiente OJIP,índices de pigmentos fotossintetizantes e teores de prolina determinados nas folhas +1. As medições da emissão de fluorescência foram realizadas durante o período de sete dias, a cada dois dias, entre 10 e 12 h da manhã, com auxílio de fluorímetro (OS-30P) e clipes fixados na porção mediana do limbo foliar, os índices de pigmentos foram determinados no mesmo período com auxílio de um medidor portátil de clorofila (Clorofilog CFL 1030) enquanto que o teor de prolina no final do experimento.Os níveis de emissão de fluorescência e os índices de pigmentos fotossintéticos reduziram com o aumento da restrição hídrica em ambas cultivar. A cultivar RB 93-509 acumulou maior teor de prolina ao nível de estresse de 60% da Cc. Com o aumento do estresse severo de restrição hídrica ocorre redução total nos níveis de fluorescência da clorofila e índices de pigmentos fotossintéticos ao sétimo dia de estresse em ambas cultivar de cana-de-açúcar. A cultivar RB 93-509 apresenta maior sensibilidade ao estresse hídrico que a cultivar RB 85-5536.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increasing demand for biofuels has provided significant increases in the areas of sugar cane in Brazil and in recent decades,and long periods of drought have limited the production of this species. This study aimed to evaluate the performance of cultivars RB 85-5536 and RB 93-509 of cane sugar on water restriction during the first stages of development. Experiment was carried out in the greenhouse of the Department of Agronomic Engineering at UFS in randomized blocks in factorial2 x 4, two cultivars (RB 85-5536 and RB 93-509) and four levels of water in the soil based on predefined at field capacity (100% Cc, 80% Cc, 60% Cc and 40% Cc), with four replications, each replicate consisting of a plant. Were evaluated the initial fluorescence emission (F0), maximum fluorescence (Fm), the quantum yield of photosystem (Fv/Fm) and fluorescence transient OJIP, indices of photosynthetic pigments and proline contents determined in leaves determined +1. The measurements of emission of fluorescence were performed during the period of seven days every two days, from 10 to 12 am, with the aid of fluorometer (OS-30P) and clips fixed on the central portion of the leaf, the contents of pigments were determined in the same period with the aidofaportable chlorophyllmeter (Clorofilog CFL 1030) whereas the proline content in the end of the experiment. The fluorescence emission levels and rates of photosynthetic pigments decreased with the increase of water restriction in both cultivars. The cultivar RB 93-509 has accumulated higher proline contentat the level of stress 60% of Cc. With the increase of stress severe by water restriction occurs a reduction in total levels of chlorophyll fluorescence and photosynthetic pigment contents from the seventh day of stress in both varieties of sugar cane. The cultivar RB 93-509 presents greater sensitivity to water stress than the cultivar RB 85-5536. / A crescente demanda por biocombustíveis tem proporcionado aumentos significativos das áreas de cana-de-açúcar no Brasil e nas últimas décadas os períodos prolongados de seca têm limitado a produção dessa espécie. Esse trabalho teve por objetivo avaliar o comportamento das cultivares RB 85-5536 e RB 93-509 de cana-deaçúcar quanto à restrição hídrica visando à seleção precoce. O experimento foi conduzido em casa de vegetação do Departamento de Engenharia Agronômica da UFS em delineamento experimental de blocos ao acaso em esquema fatorial 2 x 4, duas cultivares (RB 85- 5536 e RB 93-509) e quatros níveis de água no solo predefinidos com base na capacidade de campo (100% Cc, 80% Cc, 60% Cc e 40% Cc), com quatro repetições, sendo cada repetição constituída por uma planta. Foram avaliadas a emissão de fluorescência inicial (F0), fluorescência máxima (Fm), rendimento quântico do fotossistema (Fv/Fm) e fluorescência transiente OJIP,índices de pigmentos fotossintetizantes e teores de prolina determinados nas folhas +1. As medições da emissão de fluorescência foram realizadas durante o período de sete dias, a cada dois dias, entre 10 e 12 h da manhã, com auxílio de fluorímetro (OS-30P) e clipes fixados na porção mediana do limbo foliar, os índices de pigmentos foram determinados no mesmo período com auxílio de um medidor portátil de clorofila (Clorofilog CFL 1030) enquanto que o teor de prolina no final do experimento.Os níveis de emissão de fluorescência e os índices de pigmentos fotossintéticos reduziram com o aumento da restrição hídrica em ambas cultivar. A cultivar RB 93-509 acumulou maior teor de prolina ao nível de estresse de 60% da Cc. Com o aumento do estresse severo de restrição hídrica ocorre redução total nos níveis de fluorescência da clorofila e índices de pigmentos fotossintéticos ao sétimo dia de estresse em ambas cultivar de cana-de-açúcar. A cultivar RB 93-509 apresenta maior sensibilidade ao estresse hídrico que a cultivar RB 85-5536.

Os biossurfatantes (BS) são produtos de origem microbiana com propriedades tensoativas e emulsificantes. Estes compostos são candidatos para substituir os surfatantes sintéticos em aplicações industriais devido à sua menor toxicidade, maior biodegradabilidade, maior diversidade química e maior eficiência e efetividade em condições físicas extremas de salinidade, pressão e temperatura. O uso comercial e industrial dos BS ainda não é sustentável devido a seu alto custo de produção relacionado principalmente ao baixo rendimento. A utilização de substratos de baixo custo e ferramentas estatísticas para melhorar o rendimento de produção dos BS são duas das principais estratégias para tratar este problema. O objetivo do trabalho foi estudar a produção e recuperação do BS produzido por B. luteolum, visando o melhoramento na sua produção através do uso do planejamento fatorial e caracterizar a estrutura química do BS. A partir dos resultados, determinou-se que a adsorção em resina foi mais efetiva para a recuperação do BS comparada com a precipitação ácida. A produção do BS foi melhorada através de um planejamento fatorial 23 usando como fatores as concentrações da fonte de carbono (vaselina), a fonte de nitrogênio (nitrato de amônio) e a água do mar artificial e como resposta a tensão superficial da solução 0,1% de BS. A maior produção de BS foi obtida com 4% de fonte de carbono, 2% de fonte de nitrogênio e 20% de água do mar artificial gerando tensão superficial de 27 mNm-1. O BS foi caracterizado como uma mistura de lipopeptídeos com ácidos graxos cujo comprimento da cadeia variou entre 10-18 unidades de carbono e um conteúdo de proteína total de 5%. Três estruturas químicas foram sugeridas para os compostos ativos: dois prolina-lipídeos com os ácidos graxos C16:0 e C18:0 respectivamente e um lipopeptídeo com uma sequência peptídica Phe-Al-X-X-Pro-Pro-Thr (X=Leu/Ile) ligada a uma cadeia de ácido graxo C16:0. Não observou-se atividade antimicrobiana contra as cepas de S. aureus, E. coli, S. enteritidis, L. monocytogenes e S. mutans nas faixas de concentrações de BS testadas. O uso de vaselina como substrato para a produção do BS sugere que a bactéria e o BS podem ser explorados para aplicações como a biorremediação e a recuperação melhorada de petróleo (EOR). / Biosurfactants (BS) are microbial-derived molecules showing tensoactive and emulsification properties. These compounds are candidates to replace synthetic surfactants for industrial applications due to their less toxicity, greater biodegradation capacity, greater chemical diversity and greater efficiency and effectiveness under extreme physical conditions of salinity, pressure and temperature. Commercial and industrial use of BS is not sustainable due their high production cost mainly related to low production yields. The use of low cost substrates and statistical tools to enhance the production yield of biosurfactants are two of the main strategies to deal with that problem. The objective of this work was to study the production and recovery of the BS produced by B. luteolum, aiming to enhance its production through a factorial experimental design, and to characterize the chemical structure of the BS. It was found that resin adsorption was more effective than acid precipitation to recover the BS. The production of BS was enhanced through a factorial experimental design 23 using the concentrations of the carbon source (mineral oil), the nitrogen source (ammonium nitrate) and artificial seawater as the factors and the surface tension of a solution 0,1% of BS as the response. The value of factors that enhanced the production of BS were 4% of carbon source, 2% of nitrogen source and 20% of artificial sea water showing a surface tension of 27mNm-1. The BS was characterized as a mix of lipopeptides with fatty acid chains varying between 10-18 carbon units and a total protein content of 5%. Three chemical structures were proposed for the active compounds: two proline-lipids with the fatty acid chains C16:0 e C18:0 respectively and a lipopeptide with a peptide sequence Phe-Al-X-X-Pro-Pro-Thr (X=Leu/Ile) linked to a fatty acid chain C16:0. BS did not show antimicrobial activity against S. aureus, E. coli, S. enteritidis, L. monocytogenes and S. mutans at concentration range tested. The use of mineral oil as a substrate for the production of the BS suggests that the bacteria and the BS can be explore for applications as bioremediation and enhanced oil recovery (EOR).

Parmi les nombreux agents thérapeutiques utilisés en oncologie, le paclitaxel (Taxol®) est sans doute celui qui a suscité le plus d'intérêt. Il est utilisé en clinique pour le traitement des cancers de l'ovaire, du sein et des poumons. Il agit comme poison du fuseau mitotique en favorisant l'assemblage de la tubuline en microtubules et en stabilisant le polymère formé. Initialement extrait de l'if du Pacifique (Taxus Brevifolia) puis obtenu par hémisynthèse à partir de la 10-déacétylbaccatine III, il est aujourd'hui produit par un procédé biotechnologique de fermentation de cellules végétales. Le paclitaxel possède une structure chimique complexe basée sur un squelette tétracyclique taxane. Une approche visant à remplacer ce squelette taxane par une structure chimique plus simple a été entreprise afin d'identifier des mimes du paclitaxel. L'identification d'un fragment chimique (fragment based drug design) dérivé de la proline par une étude de modélisation moléculaire a permis de développer de nouvelles séries de mimes du paclitaxel. Parallèlement, le remplacement du squelette taxane par une matrice peptidique cyclique utilisant des dérivés de la proline a été réalisé. Les études de modélisation moléculaire, la synthèse des mimes du paclitaxel et leur évaluation biologique seront présentées. / Among the many therapeutic agents used in oncology, paclitaxel (Taxol®) is probably the one that generated the most interest. It is used clinically for the treatment of ovarian, breast and lung cancers and acts as a mitotic spindle poison by promoting the assembly of tubulin into microtubules and stabilizing the polymer formed. Initially extracted from the Pacific yew (Taxus Brevifolia) and obtained by semi-synthesis from 10-deacetylbaccatin III, it is now produced by a biotechnological process of cell plant fermentation. Paclitaxel has a complex chemical structure based on a tetracyclic taxane skeleton. A process to replace the taxane skeleton with a simpler chemical structure was undertaken to identify paclitaxel mimics. The identification of a chemical fragment (fragment based drug design) derived from proline by a molecular modeling study has led to the design of a new series of paclitaxel mimics. Meanwhile, replacing the taxane skeleton by a cyclic peptide scaffold using proline derivatives was performed. Molecular modeling studies, synthesis of paclitaxel mimics and biological evaluation will be presented.

Streptococcus pyogenes is an important human pathogen. One of the most prominent virulence factors produced by S. pyogenes is SfbI, a surface adhesin composed of three domains: thioester domain (TED), proline-rich repeat domain (PRR) and fibronectin-binding repeat domain (FnBD). The structures and functions of TED and PRR and their contributions to the pathogenesis of streptococcal diseases are unknown. The interaction between PRR and its putative target, the intracellular actin cytoskeleton regulator Arp2/3, was investigated by both in vitro and in vivo studies. PRR was shown to inhibit Arp2/3-dependent actin polymerisation. The expression of PRR in HeLa cells caused disruption to the cytoskeleton of the cells. All data point towards a role of PRR in inhibiting the Arp2/3 complex but more evidence is needed to support this. The N-terminal domain of SfbI (TED) and four homologous domains from S. pyogenes, group G streptococci and Streptococcus pneumoniae were characterised by mass spectrometry, NMR spectroscopy and biochemical assays. All were shown to possess intramolecular thioester bonds, spontaneously formed between sides chains of Cys and Gln residues. Fibrinogen (Fg) was identified as the first binding target of bacterial TEDs with direct evidence that the thioester bond was involved in the interaction with Fg. A pull-down experiment using human plasma showed Fg is a specific binding partner of SfbI-TED. The binding sites were narrowed down to the thioester-forming Gln of SfbI-TED and Lys residues in the Fg-Aα chain, and binding potentially occurred via covalent isopeptide linkage. The data presented here suggest two new roles for SfbI, previously unknown in bacterial pathogenesis. The PRR may be the first bacterial inhibitor of the actin cytoskeleton acting by inhibiting the Arp2/3 complex. Thioester domains appear to be a shared common feature of surface proteins of many Gram-positive pathogens. They may form covalent crosslinks between bacteria and host tissue.

Although the regulation of proteins functions by allosteric interactions has been identified in many subcellular processes, long-range conformational changes in proteins are also known to be induced by molecular switches. A molecular switch based on the cis-trans isomerization of a peptidyl-prolyl bond is capable of inducing a conformational change directly to the protein backbone, which is then propagated throughout the system. However, these switches are elusive and difficult to identify due to their intrinsic dynamics in the biomolecules where they are found. Herein, we explore the conformational dynamics and free energy landscape of the SH2 domain of Interleukin-2-inducible T-Cell Kinase (ITK) to fully understand the conformational coupling between the distal cis-trans molecular switch, and its phosphotyrosine binding pocket. Using multiple microsecond-long all-atom molecular dynamics simulations in explicit water for over a total of 60 μs, we show that the cis-trans isomerization of the Asn286-Pro287 peptidyl-prolyl bond is directly correlated to the dynamics of the phosphotyrosine binding pocket, in agreement with previous NMR studies. While the cis state is localized to a single free energy basin and less dynamic, the trans state samples two distinct conformations of its binding pocket – one that recognizes the phosphotyrosine motif, and another that is similar the cis state. These results provide an atomic-level description of a less-well understood allosteric regulation by a peptidyl-prolyl cis-trans molecular switch that could aid in the understanding of normal and aberrant sub-cellular process and the identification of these elusive molecular switches in other proteins.