Abstract Background Cathepsin D (CatD) is a lysosomal proteolytic enzyme expressed in almost all tissues and organs. This protease is a multifunctional enzyme responsible for essential biological processes such as cell cycle regulation, differentiation, migration, tissue remodeling, neuronal growth, ovulation, and apoptosis. The overexpression and hypersecretion of CatD have been correlated with cancer aggressiveness and tumor progression, stimulating cancer cell proliferation, fibroblast growth, and angiogenesis. In addition, some studies report its participation in neurodegenerative diseases and inflammatory processes. In this regard, the search for new inhibitors from natural products could be an alternative against the harmful effects of this enzyme. Methods An investigation was carried out to analyze CatD interaction with snake venom toxins in an attempt to find inhibitory molecules. Interestingly, human CatD shows the ability to bind strongly to snake venom phospholipases A2 (svPLA2), forming a stable muti-enzymatic complex that maintains the catalytic activity of both CatD and PLA2. In addition, this complex remains active even under exposure to the specific inhibitor pepstatin A. Furthermore, the complex formation between CatD and svPLA2 was evidenced by surface plasmon resonance (SPR), two-dimensional electrophoresis, enzymatic assays, and extensive molecular docking and dynamics techniques. Conclusion The present study suggests the versatility of human CatD and svPLA2, showing that these enzymes can form a fully functional new enzymatic complex.

Abstract Background: Wasp venoms constitute a molecular reservoir of new pharmacological substances such as peptides and proteins, biological property holders, many of which are yet to be identified. Exploring these sources may lead to the discovery of molecules hitherto unknown. This study describes, for the first time in hymenopteran venoms, the identification of an enzymatically inactive phospholipase A2 (PLA2) from the venom of the social wasp Polybia occidentalis. Methods: P. occidentalis venom was fractioned by molecular exclusion and reverse phase chromatography. For the biochemical characterization of the protein, 1D and 2D SDS-PAGE were performed, along with phospholipase activity assays on synthetic substrates, MALDI-TOF mass spectrometry and sequencing by Edman degradation. Results: The protein, called PocTX, was isolated using two chromatographic steps. Based on the phospholipase activity assay, electrophoresis and mass spectrometry, the protein presented a high degree of purity, with a mass of 13,896. 47 Da and a basic pI. After sequencing by the Edman degradation method, it was found that the protein showed a high identity with snake venom PLA2 homologues. Conclusion: This is the first report of an enzymatically inactive PLA2 isolated from wasp venom, similar to snake PLA2 homologues.

Abstract Background: Cnidarians produce toxins, which are composed of different polypeptides that induce pharmacological effects of biotechnological interest, such as antitumor, antiophidic and anti-clotting activities. This study aimed to evaluate toxicological activities and potential as antitumor and antiophidic agents contained in total extracts from five cnidarians: Millepora alcicornis, Stichodactyla helianthus, Plexaura homomalla, Bartholomea annulata and Condylactis gigantea (total and body wall). Methods: The cnidarian extracts were evaluated by electrophoresis and for their phospholipase, proteolytic, hemorrhagic, coagulant, fibrinogenolytic, neuromuscular blocking, muscle-damaging, edema-inducing and cytotoxic activities. Results: All cnidarian extracts showed indirect hemolytic activity, but only S. helianthus induced direct hemolysis and neurotoxic effect. However, the hydrolysis of NBD-PC, a PLA2 substrate, was presented only by the C gigantea (body wall) and S. helianthus. The extracts from P. homomalla and S. helianthus induced edema, while only C gigantea and S. helianthus showed intensified myotoxic activity. The proteolytic activity upon casein and fibrinogen was presented mainly by B. annulata extract and all were unable to induce hemorrhage or fibrinogen coagulation. Cnidarian extracts were able to neutralize clotting induced by Bothrops jararacussu snake venom, except M. alcicornis. All cnidarian extracts were able to inhibit hemorrhagic activity induced by Bothrops moojeni venom. Only the C. gigantea (body wall) inhibited thrombin-induced coagulation. All cnidarian extracts showed antitumor effect against Jurkat cells, of which C. gigantea (body wall) and S. helianthus were the most active; however, only C. gigantea (body wall) and M. alcicornis were active against B16F10 cells. Conclusion: The cnidarian extracts analyzed showed relevant in vitro inhibitory potential over the activities induced by Bothrops venoms; these results may contribute to elucidate the possible mechanisms of interaction between cnidarian extracts and snake venoms.

ABSTRACT Objective The aim of this paper is to develop a computer algorithm that analyzes pedestrian behavior at an urban site in Bogota, Colombia, considering that the assessment of pedestrian behavior is a road safety priority. Methods Pedestrians were video-taped as they crossed a selected road. An algorithm was developed in order to record, from these videos, pedestrian and vehicle positions and speeds. This information made possible the identification of hazardous behaviors, which were compared through visual assessments. Results 429 pedestrians crossed the selected road at an average distance of 4.5 meters from vehicles that moved at an average speed of 21 km/h. With a maximum difference of 19 % with respect to visual assessments, the algorithm estimated that 58.5 % pedestrians crossed through non-designated locations; 62.2 % crossed near moving vehicles, and that 41.2 % ran while they were crossing the road. Conclusions Video-based analysis can be used to assess pedestrians’ behavior. Future research work should focus on improving both the accuracy and the number of safety parameters of the algorithm.

RESUMEN Objetivo La medición del comportamiento de peatones es una prioridad de la seguridad vial. Por lo anterior, se desarrolló un algoritmo para analizar el comportamiento de los peatones en una zona urbana de Bogotá, Colombia. Métodos Los peatones fueron filmados mientras cruzaban la calle. Mediante el algoritmo se midieron las posiciones y velocidades de peatones y vehículos en los videos. Se identificaron los comportamientos riesgosos y se compararon visualmente. Resultados 429 peatones cruzaron la vía a una distancia promedio de 4.5 metros de los vehículos (velocidad promedio 21 km/h). El algoritmo estimó, con una diferencia máxima de 19 % con respecto a lo observado, que 58.5 % de los peatones cruzaron por zonas incorrectas, 62.2 % cruzaron cerca de vehículos en movimiento y 41.2 % corrieron al cruzar. Conclusiones El análisis basado en video puede utilizarse para medir el comportamiento de los peatones. Los trabajos sobre el tema que se realicen en el futuro deben enfocarse en mejorar la precisión y los parámetros de seguridad del algoritmo.

RESUMEN Objetivo La medición del comportamiento de peatones es una prioridad de la seguridad vial. Por lo anterior, se desarrolló un algoritmo para analizar el comportamiento de los peatones en una zona urbana de Bogotá, Colombia. Métodos Los peatones fueron filmados mientras cruzaban la calle. Mediante el algoritmo se midieron las posiciones y velocidades de peatones y vehículos en los videos. Se identificaron los comportamientos riesgosos y se compararon visualmente. Resultados 429 peatones cruzaron la vía a una distancia promedio de 4.5 metros de los vehículos (velocidad promedio 21 km/h). El algoritmo estimó, con una diferencia máxima de 19 % con respecto a lo observado, que 58.5 % de los peatones cruzaron por zonas incorrectas, 62.2 % cruzaron cerca de vehículos en movimiento y 41.2 % corrieron al cruzar. Conclusiones El análisis basado en video puede utilizarse para medir el comportamiento de los peatones. Los trabajos sobre el tema que se realicen en el futuro deben enfocarse en mejorar la precisión y los parámetros de seguridad del algoritmo.

ABSTRACT Objective The aim of this paper is to develop a computer algorithm that analyzes pedestrian behavior at an urban site in Bogota, Colombia, considering that the assessment of pedestrian behavior is a road safety priority. Methods Pedestrians were video-taped as they crossed a selected road. An algorithm was developed in order to record, from these videos, pedestrian and vehicle positions and speeds. This information made possible the identification of hazardous behaviors, which were compared through visual assessments. Results 429 pedestrians crossed the selected road at an average distance of 4.5 meters from vehicles that moved at an average speed of 21 km/h. With a maximum difference of 19 % with respect to visual assessments, the algorithm estimated that 58.5 % pedestrians crossed through non-designated locations; 62.2 % crossed near moving vehicles, and that 41.2 % ran while they were crossing the road. Conclusions Video-based analysis can be used to assess pedestrians’ behavior. Future research work should focus on improving both the accuracy and the number of safety parameters of the algorithm.

A atividade leishmanicida do ácido 3,4,5-trimetoxi-dihidrocinâmico (TMPP) isolado do extrato hidroalcoólico de frutos de Piper turbeculatum Jacq. amazônica foi testado em ensaios in vitro utilizando formas promastigotas de Leishmania amazonensis. O TMPP foi utilizado em culturas de L. amazonensis nas concentrações de 1600 a 6,25 µg/mL. A viabilidade celular das formas promastigotas foi observada em 24, 48, 72 e 96 h para cálculo da CI50. O TMPP apresentou efeito leishmanicida dose dependente para as formas promastigotas de L. amazonensis apresentando CI50 de 145 µg/mL.

Leishmanicidal activity of the 3-(3,4,5-trimethoxyphenyl) propanoic acid (TMPP) isolated from EtOH extracts of the Amazonian Piper turbeculatum Jacq. fruits was evaluated in vitro using Leishmania amazonensis promastigotes. The TMPP was assayed at concentrations of 1600 to 6.25 µg/mL for 24, 48, 72 and 96 h. Promastigotes viability was analyzed and the IC50 of TMPP was 145 µg/mL.