Plant defensins are cysteine-rich cationic peptides, components of the innate immune system. The antifungal sensitivity of certain exemplars was correlated to the level of complex glycosphingolipids in the membrane of fungi strains. Psd1 is a 46 amino acid residue defensin isolated from pea seeds which exhibit antifungal activity. Its structure is characterized by the so-called cysteine-stabilized alpha/beta motif linked by three loops as determined by two-dimensional NMR. In the present work we explored the measurement of heteronuclear Nuclear Overhauser Effects, R1 and R2 (15)N relaxation ratios, and chemical shift to probe the backbone dynamics of Psd1 and its interaction with membrane mimetic systems with phosphatidylcholine (PC) or dodecylphosphocholine (DPC) with glucosylceramide (CMH) isolated from Fusarium solani. The calculated R2 values predicted a slow motion around the highly conserved among Gly12 residue and also in the region of the Turn3 His36-Trp38. The results showed that Psd1 interacts with vesicles of PC or PC:CMH in slightly different forms. The interaction was monitored by chemical shift perturbation and relaxation properties. Using this approach we could map the loops as the binding site of Psd1 with the membrane. The major binding epitope showed conformation exchange properties in the mus-ms timescale supporting the conformation selection as the binding mechanism. Moreover, the peptide corresponding to part of Loop1 (pepLoop1: Gly12 to Ser19) is also able to interact with DPC micelles acquiring a stable structure and in the presence of DPC:CMH the peptide changes to an extended conformation, exhibiting NOE mainly with the carbohydrate and ceramide parts of CMH.

Resveratrol is a polyphenol found in black grapes and red wine and has many biological activities. In this study, we evaluated the effect of resveratrol alone and in association with amphotericin B (AMB) against Leishmania amazonensis. Our results demonstrate that resveratrol possesses both antipromastigote and antiamastigote effects, with 50% inhibitory concentrations (IC 50 s) of 27 and 42 M, respectively. The association of resveratrol with AMB showed synergy for L. amazonensis amastigotes, as demonstrated by the mean sums of fractional inhibitory index concentration (mean ⌺FIC) of 0.483, although for promastigotes, this association was indifferent. Treatment with resveratrol increased the percentage of promastigotes in the sub-G 0 /G 1 phase of the cell cycle, reduced the mitochondrial potential, and showed an elevated choline peak and CH 2 -to-CH 3 ratio in the nuclear magnetic resonance (NMR) spectroscopy analysis; all these features indicate parasite death. Resveratrol also decreased the activity of the enzyme arginase in uninfected and infected macrophages with and without stimulation with interleukin-4 (IL-4), also implicating arginase inhibition in parasite death. The anti-Leishmania effect of resveratrol and its potential synergistic association with AMB indicate that these compounds should be subjected to further studies of drug association therapy in vivo.

Introdução: Os zoológicos desempenham importante papel na conservação da fauna silvestre através de pesquisas cientificas, educação ambiental e recuperação de espécies ameaçadas de extinção. Em contrapartida, são grandes geradores de resíduos sólidos provenientes das atividades de manejo e manutenção. A compostagem pode contribuir para a destinação correta dos resíduos dos animais, e o adubo orgânico gerado nesse processo pode ser utilizado nos canteiros e jardins do parque. Objetivo: Analisar a eficiência da compostagem como alternativa para reciclagem dos resíduos sólidos orgânicos gerados em zoológicos. Metodologia: A pesquisa foi desenvolvida em um Parque Zoológico em área urbana na cidade de Santos/SP. A técnica foi preparada em caixa d’água contendo furos na parte inferior para liberação do chorume. Na primeira etapa, durante 10 dias, foi abastecida com os resíduos alimentares dos animais, depositados sobre uma camada de substrato vegetal e cobertos com palha seca. Na segunda etapa, a composteira entrou em processo de descanso onde não ocorreu abastecimento. O revolvimento da pilha continuou sendo feito, assim como o controle da umidade e temperatura. Resultado: Por dia foram colocados na composteira em média 6,65 kg de resíduos orgânicos, totalizando nos 10 dias 66,5 kg. Durante todo o processo não houve proliferação de insetos ou roedores, nem qualquer odor desagradável. A temperatura interna no início chegou em 60°, diminuindo para 34° quando se manteve estável. O composto orgânico começou a ser formado a partir da 6ª semana, mudando parcialmente a característica do resíduo original. Conclusão: Mesmo idealizado para uma estimativa de curto prazo e baixa quantidade de resíduos orgânicos, o processo de compostagem mostrou-se capaz de diminuir o descarte inapropriado dos resíduos orgânicos gerados no parque e uma alternativa que pode ser feita em grande escala com o uso de técnicas apropriadas e de baixo custo. Para amplitudes maiores se faz necessária a implantação de novas composteiras, para que ocorra a alternância entre períodos de descanso e abastecimento.

Entry of enveloped animal viruses into their host cells always depends on a step of membrane fusion triggered by conformational changes in viral envelope glycoproteins. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion at the acidic environment of the endosomal compartment. In a previous work, we identified a specific sequence in the VSV G protein, comprising the residues 145-164, directly involved in membrane interaction and fusion. In the present work we studied the interaction of pep[145-164] with membranes using NMR to solve the structure of the peptide in two membrane-mimetic systems: SDS micelles and liposomes composed of phosphatidylcholine and phosphatidylserine (PC:PS vesicles). The presence of medium-range NOEs showed that the peptide has a tendency to form N- and C-terminal helical segments in the presence of SDS micelles. Analysis of the chemical shift index indicated helix-coil equilibrium for the C-terminal helix under all conditions studied. At pH 7.0, the N-terminal helix also displayed a helix-coil equilibrium when pep[145-164] was free in solution or in the presence of PC:PS. Remarkably, at the fusogenic pH, the region of the N-terminal helix in the presence of SDS or PC:PS presented a third conformational species that was in equilibrium with the helix and random coil. The N-terminal helix content decreases pH and the minor beta-structured conformation becomes more prevalent at the fusogenic pH. These data point to a beta-conformation as the fusogenic active structure-which is in agreement with the X-ray structure, which shows a beta-hairpin for the region corresponding to pep[145-164].