Glycan alterations of serum proteins as tumour markers. Prostate-specific antigen in prostate cancer and acute-phase proteins in pancreatic cancer

Els pacients amb càncer presenten una taxa de supervivència superior si es diagnostiquen a estadis inicials, per la qual cosa és indispensable disposar de marcadors tumorals adequats. Glicoformes de proteïnes específiques es podrian utilizar com marcadors tumorals. S’han investigat les subformes i glicosilació de l’Antígen Prostàtic Específic (PSA) per millorar la seva capacitat de diagnosis de pacients amb càncer de pròstata vs aquells amb hiperplàsia benigna prostàtica. També s’han avaluat glicoproteïnes sèriques amb alteracions glucídiques en pacients de càncer de pàncrees, comparat amb pacients amb pancreatitis crònica i controls. S’ha observat una disminució de la fucosilació core i sialilació del PSA en càncer de pròstata i un augment de la fucosilació core i Sialyl-Lewis X en algunes Proteïnes de fase Aguda en càncer de pàncrees. Aquest canvis s’haurien d’avaluar en un cohort de pacients més gran per determinar el seu paper en el cribratge, diagnòstic o monitorització dels cancers estudiats.

Neoglycolipid probes prepared via oxime ligation for microarray analysis of oligosaccharide-protein interactions

Neoglycolipid technology is the basis of a microarray platform for assigning oligosaccharide ligands for carbohydrate-binding proteins. The strategy for generating the neoglycolipid probes by reductive amination results in ring opening of the core monosaccharides. This often limits applicability to short-chain saccharides, although the majority of recognition motifs are satisfactorily presented with neoglycolipids of longer oligosaccharides. Here, we describe neoglycolipids prepared by oxime ligation. We provide evidence from NMR studies that a significant proportion of the oxime-linked core monosaccharide is in the ring-closed form, and this form selectively interacts with a carbohydrate-binding protein. By microarray analyses we demonstrate the effective presentation with oxime-linked neoglycolipids of (1) Lewis(x) trisaccharide to antibodies to Lewisx, (2) sialyllactose analogs to the sialic acid-binding receptors, siglecs, and (3) N-glycans to a plant lectin that requires an intact N-acetylglucosamine core.

Fluorimetric study of the pro-oxidant activity of EUK8 in the presence of hydrogen peroxide

The catalase mimetic complex Mn(III)-salen chloride (EUK8) was found to be pro-oxidant under low hydrogen peroxide concentrations. The increase in the fluorescence rate of the probe 1,2,3-dihydrorhodamine (DHR) in solution, as well as the carbonyl content of human serum albumin were found to be maximum at H(2)O(2):EUK8 molar ratios ranging from 0 to 2, supporting previous findings regarding the mechanism of EUK8 catalase activity and the formation of highly oxidative Mn(V)-O(2-) species. This pro-oxidant effect is precluded by the presence of glutathione. Cytotoxicity to HeLa cells, as probed by increased rate of oxidation of intracellular DHR, was not observed. Our findings suggest that the combination of H(2)O(2) and EUK8 at specific molar ratios, in the absence of reductants/antioxidants, induces the oxidation of organic molecules. It is shown that the fluorimetric determination of pro-oxidant activity of metal complexes is more sensitive than the colorimetric quantification of protein carbonyl content. The implications of our findings with respect to the somewhat confusing results arising from in vivo studies of EUK8 and other Mn(III) anti-oxidant metal complexes are discussed.

Mild mitochondrial uncoupling in mice affects energy metabolism, redox balance and longevity

Caloric restriction is the most effective non-genetic intervention to enhance lifespan known to date. A major research interest has been the development of therapeutic strategies capable of promoting the beneficial results of this dietary regimen. In this sense, we propose that compounds that decrease the efficiency of energy conversion, such as mitochondrial uncouplers, can be caloric restriction mimetics. Treatment of mice with low doses of the protonophore 2,4-dinitrophenol promotes enhanced tissue respiratory rates, improved serological glucose, triglyceride and insulin levels, decrease of reactive oxygen species levels and tissue DNA and protein oxidation, as well as reduced body weight. Importantly, 2,4-dinitrophenol-treated animals also presented enhanced longevity. Our results demonstrate that mild mitochondrial uncoupling is a highly effective in vivo antioxidant strategy, and describe the first therapeutic intervention capable of effectively reproducing the physiological, metabolic and lifespan effects of caloric restriction in healthy mammals.

Annexin 1 peptides protect against experimental myocardial ischemia-reperfusion: analysis of their mechanism of action

Myocardial reperfusion injury is associated with the infiltration of blood-borne polymorphonuclear leukocytes. We have previous described the protection afforded by annexin 1 (ANXA1) in an experimental model of rat myocardial ischemia-reperfusion (IR) injury. We examined the 1) amino acid region of ANXA1 that retained the protective effect in a model of rat heart IR; 2) changes in endogenous ANXA1 in relation to the IR induced damage and after pharmacological modulation; and 3) potential involvement of the formyl peptide receptor (FPR) in the protective action displayed by ANXA1 peptides. Administration of peptide Ac2-26 at 0, 30, and 60 min postreperfusion produced a significant protection against IR injury, and this was associated with reduced myeloperoxidase activity and IL-1 beta levels in the infarcted heart. Western blotting and electron microscopy analyses showed that IR heart had increased ANXA1 expression in the injured tissue, associated mainly with the infiltrated leukocytes. Finally, an antagonist to the FPR receptor selectively inhibited the protective action of peptide ANXA1 and its derived peptides against IR injury. Altogether, these data provide further insight into the protective effect of ANXA1 and its mimetics and a rationale for a clinical use for drugs developed from this line of research.

Structural basis for branching-enzyme activity of glycoside hydrolase family 57: Structure and stability studies of a novel branching enzyme from the hyperthermophilic archaeon Thermococcus Kodakaraensis KOD1

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular adaptability of nucleoside diphosphate kinase b from trypanosomatid parasites: stability, oligomerization and structural determinants of nucleotide binding

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Simple mucin-type carbohydrate antigens (T, sialosyl T, Tn and sialosyl-Tn) in breast carcinogenesis

Immunohistochemical analysis of the expression of simple mucin-type carbohydrate antigens (Tn, sialyl-Tn and T) was performed in a series of 43 cases of intraductal hyperplasia without atypia, 9 cases of intraductal hyperplasia with atypia, 54 cases of ductal carcinoma in situ (DCIS) and 26 cases of invasive breast carcinoma. We also studied 36 cases of isolated breast normal epithelium, 20 cases of 'normal' breast epithelium adjacent to neoplasms and 14 cases of apocrine metaplasia. All antigens were detected in different frequencies in normal, hyperplastic, metaplastic and neoplastic breast epithelium. Tn and sialyl-Tn are expressed more frequently in malignant than in benign breast epithelium; while Tn expression increases from normal to invasive carcinomas, sialyl-Tn increases until DCIS and drops in invasive carcinomas, suggesting that either there is a failure of a proportion of DCIS to progress to invasive carcinoma or loss of expression of sialyl-Tn when some carcinomas become invasive. The high frequency of Tn and sialyl-Tn expression in breast intraductal proliferations probably reflects incomplete glycosylation in these lesions, which is a well-known tumour-associated phenomenon and supports the assumption that such lesions are putative precursors of breast cancer. T antigen was expressed in all groups studied, but its prevalence differed significantly between normal and neoplastic epithelium. The expression of these antigens in epithelium adjacent to carcinomas is similar to that found in isolated normal breast epithelium, whereas apocrine metaplasia has a pattern of simple mucin-type glycosylation that is specific and distinct from that of the normal breast epithelium, with a high frequency of marked expression of Tn and sialyl-Tn. The similarity of the pattern of expression of simple mucin-type antigens in metaplasia and malignant neoplasia reduces the usefulness of these markers from a diagnostic standpoint.

Estudo da formação de domínios em bicamadas lipídicas induzidos por peptídeos antimicrobianos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese em fase sólida e estudos comformacionais de análogos contendo TOAC de um peptídeo de rã Hypsiboas albopunctatus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morfologia e taxonomia de Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae) e seu relacionamento mimético com corais verdadeiras na Amazônia

A coloração animal é um importante atributo biológico com diferentes funções relacionadas às estratégias de vida adotadas pelos indivíduos no ambiente, como a termorregulação, a defesa e a comunicação inter e intraespecífica. O mimetismo é talvez, um dos mais importantes mecanismos biológicos de comunicação, frequentemente envolvendo similaridade de cor com conotação defensiva. Os sistemas miméticos refletem um complexo processo de evolução, que acentua semelhanças morfológicas ou comportamentais entre duas ou mais espécies, garantindo vantagens adaptativas em pelo menos uma delas. Apesar de comum entre os invertebrados, o mimetismo também pode ser observado em grupos de vertebrados como lagartos e serpentes, por exemplo. Dentre os exemplos mais comuns de mimetismo em serpentes são descritas as relações entre os corais verdadeiras e falsas. A falsa-coral, Atractus latifrons (Günther, 1868) é endêmica da Amazônia e ocorre nos territórios de Brasil, Colômbia, Guiana Francesa, Peru, Suriname e Venezuela. Em função da semelhança cromática de seus diferentes padrões, esta espécie foi relacionada à algumas espécies de corais verdadeiras do gênero Micrurus que também apresentam distribuição amazônica. Embora a variação cromática desta espécie tenha sido relatada por alguns autores, algumas questões sobre o polimorfismo intraespecífico e sua relação com a distribuição geográfica, assim como a relação mimética com as corais verdadeiras de Micrurus ainda não foram estudadas. Com o objetivo de contribuir com a elucidação destas questões, este estudo foi organizado em dois capítulos: no primeiro capítulo, intitulado “Variação morfológica e taxonomia de Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae)”, foram apresentadas as variações da morfologia externa e hemipeniana da espécie, incluindo sua redescrição e descrição do holótipo, além das descrições dos padrões cromáticos e análise de dimorfismo sexual; e no segundo capítulo, intitulado “Relações miméticas entre Atractus latifrons e corais verdadeiras na Amazônia”, foram identificados os possíveis modelos miméticos para A. latifrons, inferindo suas relações miméticas através da análise de co-ocorrência e apresentando mapas de distribuição dos padrões miméticos entre as espécies envolvidas.

Peptídeos derivados da toxina ParE: síntese, estrutura e estudos de inibição de DNA topoisomerases

Pós-graduação em Biotecnologia - IQ

Efeito da utilização de substitutos de gordura em queijos light

Cheeses are known to be sources of calcium, phosphorus and protein, important nutrients for a suitable nutrition. However, certain cheeses imply the ingestion of large amounts of fats, which can cause the development of coronary heart and carcinogenic diseases. Although consumers are aware of the necessity of reducing the fats intake, they are still not pleased with the quality of light cheeses available on the market, because the partial or total fat removal provides some undesirable changes, especially regarding to the product texture and flavor. In order to offer products nutritionally adequate and palatable, alternatives have been developed to improve the characteristics of light cheeses. Such alternatives include the use of fat substitutes, those additives that improve the functional and sensory characteristics of cheeses with reduced fat. Fat substitutes composed of proteins, carbohydrates and lipids, or a combination of them, help the retention of moisture and eliminate the undesirable characteristics of fat reduced-cheeses. In this context, this review aims at reporting the innovations and trends on the use of fat substitutes to produce light cheeses.

Efeitos da dimerização na estrutura e atividade biológica dos peptídeos antimicrobianos Aureína 1.2 e Magainina 2

Pós-graduação em Biotecnologia - IQ

Synthesis of selenium-linked neoglycoconjugates and pseudodisaccharides

The introduction of organoselenium moieties within the structure of carbohydrates has received attention recently. Herein, we report on the synthesis of selenium-containing neoglycoconjugates and pseudodisaccharides by the reaction of nucleophilic selenium species, generated from sugar diselenides, with chiral N-Boc aziridines and sugar tosylates. The reaction proceeds with moderate to good yields for various substrates. The introduction of organoselenium moieties within the framework of various sugars, with increased levels of complexity, thus allowing the synthesis of disaccharide and glycoconjugate mimetics. (C) 2012 Elsevier Ltd. All rights reserved.