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Plasmonic metal nanoparticles (NPs) can be used as enhancers of the efficiency of standard photosensitizers (PSs) in photodynamic therapy (PDT). Protein corona, the adsorption layer that forms spontaneously around NPs once in contact with biological fluids, determines to a great extent the efficiency of PDT. In this work, we explore the possibility that pectin-coated Au NPs (Au@Pec NPs) could act as adjuvants in riboflavin (Rf)-based PDT by comparing the photodamage in HeLa cells cultured in the presence and in the absence of the NPs. Moreover, we investigate the impact that the preincubation of Rf and Au@Pec NPs (or Ag@ Pec NPs) at two very different serum concentrations could have on cell’s photodamage. Because reactive oxygen species (ROS) precursors are the excited states of the PS, the effect of proteins on the photophysics of Rf and Rf/plasmonic NPs was studied by transient absorption experiments. The beneficial effect of Au@Pec NPs in Rf-based PDT on HeLa cells cultured under standard serum conditions was demonstrated for the first time. However, the preincubation of Rf and Au@Pec NPs (or Ag@Pec NPs) with serum has undesirable results regarding the enhancement of Rf-based PDT. In this sense, we also verified that more concentrated protein conditions result in lower amounts of the triplet excited state of Rf and thus an expected lower production of ROS, which are the key elements for PDT’s efficacy. These findings point out the relevance of serum concentration in the design of in vitro cell culture experiments carried out to determine the best way to combine and use potential sensitizers with plasmonic NPs to develop more effective PDTs., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Instituto de Biotecnología y Biología Molecular

Protease inhibitors (PIs) have been traditionally recognized by their potential biomedical application in events with exacerbation of endogenous proteases activity. Plant PIs have gained interest as naturally occurring molecules, which usually show lower environmental impact residual toxicity than synthetic compounds. In this work, we isolated, cloned, expressed and purified a novel trypsin inhibitor from S. tuberosum subsp. andigenum var. overa, named oPTI. A significant over-expression of the oPTI coding gene after 48 h exposure of methyl jasmonate compared to the gene of reference. This inhibitor showed a molecular mass of 12 kDa and a Ki of 7.3 × 10−7 M. Finally, we evaluated the antimicrobial activity of oPTI against different pathogenic microorganisms. The oPTI demonstrated inhibitory effect on the growth of Acinetobacter baumannii S-1, Acinetobacter baumannii R, Acinetobacter calcoaceticus R, Acinetobacter calcoaceticus S, Bacillus stearothermophilus, Escherichia coli, Pseudomonas aeruginosa, Salmonella braenderup, Salmonella enteritidis, Salmonella typhimurium and Yersinia enterocolitica strains. This study represents the first report for the antimicrobial activity of a plant PI over a wide range of microorganisms. Our studies reinforce the importance of natural PIs as promising molecules for their potential application in the biomedical field and/or in the food industry as natural food preservatives.

trans-Sialidase and cruzipain are important virulence factors from Trypanosoma cruzi, the etiological agent of Chagas disease, that have highly antigenic domains in their structure and were reported as potential tools for diagnosis of the illness. The aim of the present study is to assess the possibility of using cruzipain and the catalytic domain of trans-sialidase in a Surface Plasmon Resonance-based immunosensor for the diagnosis of chronic Chagas disease. Immunoassays carried out with canine sera verified that cruzipain allows the detection of anti-Trypanosoma cruzi antibodies whereas recombinant trans-sialidase did not yield specific detections, due to the high dilutions of serum used in the immunoassays that hinder the possibility to sense the specific low titer antibodies. The developed cruzipain-based biosensor, whose price per assay is comparable to a commercial enzyme-linked immunosorbent assay (ELISA), was successfully applied for the rapid quantification of specific antibodies against Trypanosoma cruzi in fresh human sera showing an excellent agreement with ELISA Fil: Chain, Cecilia Yamil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Pires Souto, Dênio Emanuel. Universidade Federal do Paraná; Brasil Fil: Sbaraglini, Maria Laura. Universidad Nacional de La Plata. Facultad de Ciencas Exactas. Laboratorio de Investigación y Desarrollo de Bioactivos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Labriola, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Daza Millone, Maria Antonieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Ramirez, Eduardo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Cisneros, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Lopez Albizu, Maria Constanza. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán". Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben"; Argentina Fil: Scollo, Karenina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán". Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben"; Argentina Fil: Kubota, Lauro T.. Universidade Estadual de Campinas; Brasil Fil: Ruiz, Andrés Mariano. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán". Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben"; Argentina Fil: Vela, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina

The development of drug carriers based in lipid nanoparticles (LNPs) aims toward the synthesis of non-toxic multifunctional nanovehicles that can bypass the immune system and allow specific site targeting, controlled release and complete degradation of the carrier components. Among label free techniques, Surface Plasmon Resonance (SPR) biosensing is a versatile tool to study LNPs in the field of nanotherapeutics research. SPR, widely used for the analysis of molecular interactions, is based on the immobilization of one of the interacting partners to the sensor surface, which can be easily achieved in the case of LNPs by hydrophobic attachment onto commercial lipid- capture sensor chips. In the last years SPR technology has emerged as an interesting strategy for studying molecular aspects of drug delivery that determines the efficacy of the nanotherapeutical such as LNPs' interactions with biological targets, with serum proteins and with tumor extracelullar matrix. Moreover, SPR has contributed to the obtention and characterization of LNPs, gathering information about the interplay between components of the formulations, their response to organic molecules and, more recently, the quantification and molecular characterization of exosomes. By the combination of available sensor platforms, assay quickness and straight forward platform adaptation for new carrier systems, SPR is becoming a high throughput technique for LNPs' characterization and analysis., Facultad de Ciencias Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

Se sabe que los productos naturales constituyen una de las mayores fuentes de materia prima para el desarrollo de medicamentos y agentes antimicrobianos, debido a su diversidad química y a que se les supone una toxicidad inicial limitada al encontrarse en seres vivos. Requieren menor costo de obtención y procedimientos relativamente sencillos, si se comparan con los procedimientos de obtención por la vía de la síntesis química. Las fuentes vegetales de inhibidores peptídicos de proteasas (IPPs) han sido escasamente exploradas y tienen la ventaja de su extraordinaria riqueza y diversidad y, en muchos casos la inexistencia de patentes y procedimientos de extracción, dificultan su explotación. Los estudios referidos a material botánico de la flora latinoamericana son más escasos aún. Por ello, resulta de sumo interés el estudio de nuevos IPPs de origen natural para su potencial implementación como aditivo natural alimentario; así como el estudio de su vehiculización al sistema gástrico cuando forman parte de alimentos, sus absorciones, estabilidades y acciones orgánicas en tejidos centrales y periféricos., Facultad de Ciencias Exactas

Protease inhibitors have been considered only as long as anti-nutritional factors, but have regained much interest in recent years because of their potential anti-cancer action and also because of its positive dietary effects. A new potato carboxypeptidase inhibitor (PCI) was isolated using proteomics techniques; the inhibitor was detected in an extract of Solanum tuberosum cv. Desiree by intensity fading MALDI-TOF mass spectrometry, and then was purified and characterised. The mass spectral from tryptic digestion (peptide mass fingerprint) was analysed with the “MASCOT search tool” and did not match any of the inhibitors of other plants. Protein identification and differentiation by peptide mass fingerprinting (PMF) has been adopted in our group as an excellent tool to differentiate, in fast an unequivocal way, proteins with very similar physicochemical and functional properties. The new PCI exhibited a molecular mass of 4218 Da and consists of a single polypeptide chain with an isoelectric point of 6.5. MALDI-TOF/TOF sequence analysis allowed determines a sequence belonging to the inhibitor.

In this work, araujiain (enzymatic preparation obtained from the latex of Araujia hortorum fruits) was successfully immobilized on glyoxyl-agarose via multipoint covalent attachment. Thus, good efficiency of immobilization and high operational stability of immobilized enzyme were obtained. The activity of araujiain at alkaline pH was significantly improved after immobilization. In addition, immobilized araujiain also showed high activity and good stability, without significant loss in its activity, at temperatures between 37 and 60°C and in the presence of immiscible organic solvents. Immobilized araujiain also showed good performance in a mixture of 50% ethyl acetate in buffer, used for peptide synthesis, with better results than when the free enzyme was used as catalyst. These results indicate that immobilized araujiain via multipoint covalent attachment can be highly stabilized and this method might be used for practical applications of araujiain in hydrolytic and synthetic processes., Centro de Investigación de Proteínas Vegetales