Biochemistry and molecular biology education in Latin America and the Iberian Peninsula - Part 2

[Excerpt] This is the second issue of Biochemistry and Molecular Biology Education (BAMBED) focusing on innovations and research on Biochemistry and Molecular Biology (BMB) education from Latin America, Portugal and Spain. The first issue with this focus is published in Biochemistry and Molecular Biology Education, Volume 37, Issue 5 (2009). The manuscripts in these special issues resulted from an invitation disseminated through the mailing lists of national BMB societies and were processed according to the journal’s regular editorial peer review. The initiative was implemented to encourage the research and communication of educational experiences in Latin America and Iberia. Therefore this is an opportune moment to analyze the experience and draw implications for the future. The publication of these two special issues with original reports from the aforementioned regions confirms that there are contributions of education in Molecular Life Sciences from different areas of our flat world that are out there waiting for an opportunity or motivation to be written. Some of the reports published here are authored by molecular life scientists with no previous educational publications indexed in the ISI. We are hopeful that these authors will act as part of the transduction cascade that will diffuse and amplify the message that faculty can learn how to apply scientific research principles to their teaching and contribute relevant findings to an international audience. [...

Continuing education in structural biology for science teachers

The present paper sought to identify what perception teachers from Natural Science fields have on the use of instructional strategies that make use of models to represent biomolecules. The data presented are related to two continuing education courses\ud carried out with teachers from public schools of the state of São Paulo (Brazil). Such data showed that the teachers approved the use of instructional materials such as the ones suggested in the courses (e.g., construction of a 3-D biomolecular structure) and\ud they pointed out some advantages and obstacles to the use of such materials.\ud © 2010 Elsevier Ltd. All rights reserved

Interactive media on Chagas Disease: development and content

An interactive media on Chagas disease was developed as an educational tool, on the context of the scientific research and dissemination actions of the National Institute of Structural Biotechnology and Medicinal Chemistry in Infectious Diseases (INBEQMeDI). Different computational resources were used either in terms of hardware and software. The media contains 13 videos that range from 30 seconds to 4 minutes, all with information about Chagas disease, showing the social and economic aspects; the research made by the INBEQMeDI group; different aspects of the disease illustrated by slides arranged in a mobile carousel, and radio programs, with funny skits. The target audience for use of this feature is students aged 10 to 17 years. Teachers of areas of science and biology, through a partnership with the Agency of Education of the State of São Paulo, will be invited to plan a strategy for media use with their students.FAPESPCNP

Physico-chemical and antifungal properties of protease inhibitors from Acacia plumosa

This study was aimed at investigating the purification, biological activity, and some structural properties of three serine protease inhibitors isoforms, denoted ApTIA, ApTIB, and ApTIC from Acacia plumosa Lowe seeds. They were purified from the saline extract of the seeds, using Superdex-75 gel filtration and Mono-S ion exchange chromatography. They were further investigated by mass spectrometry, spectroscopic measurements, surface plasmon resonance, and inhibition assays with proteases and phytopathogenic fungi. The molecular mass of each isoform was estimated at ca. 20 kDa. Each contained two polypeptide chains linked by a disulfide bridge, with different isoelectric points that are acidic in nature. The N-terminal sequences of both chains indicated that they were Kunitz-type inhibitors. Circular dichroism (CD) analyses suggested the predominance of both disordered and beta-strands on ApTI isoforms secondary structure, as expected for β-II proteins. In addition, it was observed that the proteins were very stable, even at either extreme pH values or at high temperature, with denaturation midpoints close to 75 °C. The isoinhibitors could delay, up to 10 times, the blood coagulation time in vitro and inhibited action of trypsin (Ki 1.8 nM), α-chymotrypsin (Ki 10.3 nM) and kallikrein (Ki 0.58 μM). The binding of ApTIA, ApTIB, and ApTIC to trypsin and α-chymotrypsin, was investigated by surface plasmon resonance (SPR), this giving dissociation constants of 0.39, 0.56 and 0.56 nM with trypsin and 7.5, 6.9 and 3.5 nM with α-chymotrypsin, respectively. The growth profiles of Aspergillus niger, Thielaviopsis paradoxa and Colletotrichum sp. P10 were also inhibited by each isoforms. These three potent inhibitors from A. plumosa may therefore be of great interest as specific inhibitors to regulate proteolytic processes.FAPESPCNP

O DNA: uma sinopse histórica

Este artigo tem o objetivo de relatar os fatos históricos científicos mais importantes quepermitiram o entendimento atual da estrutura e funcionalidade da molécula de DNA.Acreditamos que resgatar a história e divulgá-la integra culturalmente novas e velhas geraçõesà sociedade contemporânea a que pertencemos, facilitando o aprendizado e a compreensãosobre a nossa constituição e funcionalidade, assim como nos permite especular sobre o nossofuturo, nossa evolução, a vida no planeta, e o enfoque e direcionamento de novas pesquisasdesta área científica

Xyloglucan nano-aggregates: Physico-chemical characterisation in buffer solution and potential application as a carrier for camptothecin, an anti-cancer drug

In this work, native xyloglucan was extracted from Tamarindus indica seeds (XGT), and its properties in phosphate buffer solution (PBS) were evaluated in comparison with a commercial tamarind kernel powder (TKP). The physico-chemical characteristics of the polysaccharides such as molar mass, critical concentration and intrinsic viscosity were determined. Furthermore, using spectroscopic and microscopy techniques, it was observed that the XGs tested can be considered macromolecules able to aggregate as nano-entities of 60-140 nm. The XGT tended to an ordered and compact spherical conformation determined by the Huggins constant, circular dichroism, atomic force microscopy and transmission electron microscopy. After the determination of the properties in PBS the XGs, at concentrations of 25% above their critical aggregation concentration, were used to encapsulate camptothecin, an anti-cancer drug. The XGT sample showed an encapsulation efficiency of 42% and first-order drug delivery kinetics. These results demonstrated the importance of knowledge of the physico-chemical properties of polysaccharides, for example, to better conduct their biotechnological applications as drug carriers. (C) 2010 Elsevier Ltd. All rights reserved.CNPq (Conselho Nacional de Pesquisa)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES-BrasilFundação AraucáriaFundacao Araucari

Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes

The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 µM and 155 µM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide

Trypanosoma cruzi: Isolation and characterization of aspartyl proteases

Two aspartyl proteases activities were identified and isolated from Trypanosoma cruzi epimastigotes: cruzipsin-I (CZP-I) and cruzipsin-II (CZP-II). One was isolated from a soluble fraction (CZP-II) and the other was solubilized with 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate(CZP-I). The molecular mass of both proteases was estimated to be 120 kDa by HPLC gel filtration and the activity of the enzymes was detected in a doublet of bands (56 and 48 kDa) by substrate-sodium dodecyl sulphate-polyacrylamide-gelatin gel electrophoresis. Substrate specificity studies indicated that the enzymes consistently hydrolyze the cathepsin D substrate Phe-Ala-Ala-Phe (4-NO(2))-Phe-Val-Leu-O(4)MP but failed to hydrolyze serine and other protease substrates. Both proteases activities were strongly inhibited by the classic inhibitor pepstatin-A (>= 68%) and the aspartic active site labeling agent, 1,2-epoxy-3-(phenyl-nitrophenoxy) propane (>= 80%). These findings show that both proteases are novel T. cruzi acidic proteases. The physiological function of these enzymes in T. cruzi has under investigation. (c) 2009 Elsevier Inc. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqFAPERJFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação Oswaldo Cruz (Fiocruz)FIOCRUZ (PAPES

Contribution of the Tyr-1 in Plantaricin149a to Disrupt Phospholipid Model Membranes

Plantaricin149a (Pln149a) is a cationic antimicrobial peptide, which was suggested to cause membrane destabilization via the carpet mechanism. The mode of action proposed to this antimicrobial peptide describes the induction of an amphipathic α-helix from Ala7 to Lys20, while the N-terminus residues remain in a coil conformation after binding. To better investigate this assumption, the purpose of this study was to determine the contributions of the Tyr1 in Pln149a in the binding to model membranes to promote its destabilization. The Tyr to Ser substitution increased the dissociation constant (KD) of the antimicrobial peptide from the liposomes (approximately three-fold higher), and decreased the enthalpy of binding to anionic vesicles from −17.2 kcal/mol to −10.2 kcal/mol. The peptide adsorption/incorporation into the negatively charged lipid vesicles was less effective with the Tyr1 substitution and peptide Pln149a perturbed the liposome integrity more than the analog, Pln149S. Taken together, the peptide-lipid interactions that govern the Pln149a antimicrobial activity are found not only in the amphipathic helix, but also in the N-terminus residues, which take part in enthalpic contributions due to the allocation at a lipid-aqueous interface