Aristolactams and further constituents from Aristolochia chamissonis

Isolou-se do extrato etanólico de galhos de Aristolochia chamissonis espatulenol, sitosterol, sitosterol-beta-D-glicosídeo, colavelool, 13-epi-2-oxo-colavelool, trans-N-p-coumaroiltiramina, alantoína, ácido aristolóquico I e aristolactama AII. As estruturas da aristolactama AII e da piperolactama A são revisadas com base em análises espectrométricas e derivatizações químicas.

Constituintes micromoleculares de Aristolochia melastoma Manso: compostos nitrados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Depression by inbreeding after four sucessive self-pollination squash generations

The strategy for breeding F-1 hybrid squash is to develop parental lines through self-pollination. However, it increases plant mean homozygosis, which is not the natural genetic state of a cross-pollinated species, and can cause inbreeding depression. The objective of this work was to evaluate this depression with sucessive generations of self-pollination (without selection) in Cucurbita moschata, cv. Piramoita. Populations were obtained from lines with one to four generations of self-pollination (obtained by the SSD method), from the original cv. Piramoita (population SO). Randomized blocks were used with five treatments (different generations of self-pollination -S-0 to S-4), six replicates and five plants per plot. Regression analysis was made by the Wright inbreeding coefficient (F) to measure the homozygosis level effect on vigor loss. There was a linear reduction of mean weight and fruit length, seed production (number and weight) per fruit with the increase of the homozygosis level; however inbreeding did not affect seed quality (weight of 100 seeds and germination).

Acúmulo de nutrientes pela alface destinada à produção de sementes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genotyping of Brazilian Giardia duodenalis human axenic isolates

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

Fmoc-POAC: [(9-fluorenylmethyloxycarbonyl)-2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-amino-4-carboxylic acid]: A novel protected spin labeled beta-amino acid for peptide and protein chemistry

The stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (TOAC) is the only spin labeled amino acid that has been used to date to successfully label peptide sequences for structural studies. However, severe difficulty in coupling the subsequent amino acid has been the most serious shortcoming of this paramagnetic marker. This problem stems from the low nucleophilicity of TOAC's amine group towards the acylation reaction during peptide chain elongation. The present report introduces the alternative beta -amino acid 2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-amino-4-carboxylic acid (POAC), potentially useful in peptide and protein chemistry. Investigations aimed at addressing the stereochemistry of this cyclic molecule through X-ray diffraction measurements of crystalline and bulk samples revealed that it consists only of the trans conformer. The 9-fluorenylmethyloxyearbonyl group (Fmoc) was chosen for temporary protection of the POAC amine function, allowing insertion of the probe at any position in a peptide sequence. The vasoactive octapeptide angiotensin II (AII, DRVYIHPF) was synthesized by replacing Pro(7) with POAC. The reaction of Fmoc-POAC with the peptidyl-resin occurred smoothly, and the coupling of the subsequent amino acid showed a much faster reaction when compared with TOAC. POAC(7)-AII was obtained in good yield, demonstrating that, in addition to TOAC, POAC is a convenient amino acid for the synthesis of spin labeled peptide analogues. The present findings open the possibility of a wide range of chemical and biological applications for this novel beta -amino acid derivative, including structural investigations involving its differentiated bend-inducing characteristics.

Conformational basis for the biological activity of TOAC-labeled angiotensin II and bradykinin: Electron paramagnetic resonance, circular dichroism, and fluorescence studies

N-Terminally and internally labeled analogues of the hormones angiotensin (AII, DRVYIHPF) and bradykinin (BK, RPPGFSPFR) were synthesized containing the paramagnetic amino acid 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4- carboxylic acid (TOAC). TOAC replaced Asp 1 (TOAC 1-AII) and Val 3 (TOAC 3-AII) in AII and was inserted prior to Arg 1 (TOAC 0-BK) and replacing Pro 3 (TOAC 3-BK) in BK. The peptide conformational properties were examined as a function of trifluoroethanol (TFE) content and pH. Electron paramagnetic resonance spectra were sensitive to both variables and showed that internally labeled analogues yielded rotational correlation times (TC) considerably larger than N-terminally labeled ones, evincing the greater freedom of motion of the N-terminus. In TFE, τ C increased due to viscosity effects. Calculation of τ Cpeptide/τ CTOAC ratios indicated that the peptides acquired more folded conformations. Circular dichroism spectra showed that, except for TOAC 1-AII in TFE, the N-terminally labeled analogues displayed a conformational behavior similar to that of the parent peptides. In contrast, under all conditions, the TOAC 3 derivatives acquired more restricted conformations. Fluorescence spectra of All and its derivatives were especially sensitive to the ionization of Tyr 4. Fluorescence quenching by the nitroxide moiety was much more pronounced for TOAC 3-AII The conformational behavior of the TOAC derivatives bears excellent correlation with their biological activity, since, while the N-terminally labeled peptides were partially active, their internally labeled counterparts were inactive [Nakaie, C. R., et al., Peptides 2002, 23, 65-70]. The data demonstrate that insertion of TOAC in the middle of the peptide chain induces conformational restrictions that lead to loss of backbone flexibility, not allowing the peptides to acquire their receptor-bound conformation. © 2004 Wiley Periodicals, Inc.

Vascular hyporeactivity to angiotensin II induced by Escherichia coli endotoxin is reversed by Nω-Nitro-L-Arginine, an inhibitor of nitric oxide synthase

Septic shock or sepsis is reported to be one of the major causes of death when followed by systemic infectious trauma in humans and other mammals. Its development leads to a large drop in blood pressure and a reduction in vascular responsiveness to physiological vasoconstrictors which, if not contained, can lead to death. It is proposed that this vascular response is due to the action of bacterial cell wall products released into the bloodstream by the vascular endothelium and is considered a normal response of the body's defenses against infection. A reduction in vascular reactivity to epinephrine and norepinephrine is observed under these conditions. In the present study in rats, the aim was to assess whether those effects of hypotension and hyporeactivity are also related to another endogenous vasoconstrictor, angiotensin II (AII). We evaluated the variation in the power of this vasoconstrictor over the mean arterial pressure in anesthetized rats, before and after the establishment of hypotension by Escherichia coli endotoxin (Etx). Our results show that in this model of septic shock, there is a reduction in vascular reactivity to AII and this reduction can be reversed by the inhibitor of nitric oxide synthase, Nω-Nitro-L- Arginine (NωNLA). Our results also suggest that other endogenous factors (not yet fully known) are involved in the protection of rats against septic shock, in addition to the L-arginine NO pathway.

Prevalência de parasitas intestinais e caracterização genotípica de Giardia duodenalis em creche do município de Pratânia, estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnóstico e caracterização molecular de Giardia duodenalis e Cryptosporidium spp. em amostras fecais de bovinos e ovinos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aristolactamas e alcamidas isoladas de Aristolochia gigantea Mart

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da endotoxina de E.coli, NwNLA e dexametasona sobre a responsabilidade vascular à angiotensina II

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Alterações histológicas do miocárdio, rim e fígado de ratos (Rattus novergicus) Wistar submetidos à infusão de angiotensina II: influência na função ventricular esquerda e resposta ao tratamento com losartan e carvedilol

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Papel da angiotensina II e das prostaglandinas no mecanismo de regulação da função renal de cães após ingestão de uma carga de proteína

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Investigação eletroquímica e aplicação de eletrodos de carbono vítreo modificados por filmes de poli-L-lisina na determinação de antioxidantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)