IIB

URI permanente para esta comunidad

https://digital.cic.gba.gob.ar/handle/11746/5350
El Instituto de Investigaciones Biológicas (IIB), está ubicado en el Complejo Gral. Belgrano de la Universidad Nacional de Mar del Plata. En el año 2006, el CONICET y la UNMDP (Universidad Nacional de Mar del Plata) firmaron un convenio de complementación recíproca en la promoción y ejecución de tareas de investigación En el marco de dicho convenio se aprobó la creación del IIB como Unidad Ejecutora de doble dependencia, CONICET-UNMdP. Desde el año 2016 es también un Centro Asociado CIC.
Las líneas de investigación desarrolladas en el IIB son las siguientes:
Bioquímica y Biología Molecular de plantas.
Fisiología Vegetal, Bioquímica.
Biología Molecular de microorganismos y espermatozoides.
Metabolismo de proteínas en hígado de ratón, hoja de trigo y en arqueas haloalcalófilas.
La labor docente del Instituto se ve reflejada en la formación de jóvenes investigadores que realizan sus tesis de grado y doctorales, y en el dictado de varias asignaturas correspondientes a las Licenciaturas y Profesorados en Ciencias Biológicas, Ciencias Químicas y a la carrera de Bioquímica.
Director: Dr. Daleo, Gustavo Raúl

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  • Artículo
    Acceso Abierto
    Antimicrobial activity of phosphites against different potato pathogens
    (2010) Lobato, M.C.; Olivieri, F.P.; Daleo, G.R.; Andreu., A.B.
    Phosphites have low-toxicity on the environment and show high efficacy in controlling oomycete diseases in plants, both by a direct and an indirect mechanism. We have shown that they are also effective in reducing disease symptoms produced byPhytophthora infestans, Fusarium solaniandRhizoctonia solaniwhen applied to potato seed tubers. To gain better insight into the direct mode of action of phosphites on different potato pathogens, and to ascertain chemical determinants in their direct antimicrobial activity, four potato pathogens were assayed with respect to sensitivity toward calcium, potassium and copper phosphites (CaPhi, KPhi and CuPhi, respectively). The influence of acidification and ionic strength changes after Phi addition on the antimicrobial activity, and the fungicidal or fungistatic activity, were evaluated. Results showed that phosphites were able to inhibit growth of all pathogens.Phytophthora infestanswas the most inhibited pathogen by all phosphites, followed byStreptomyces scabies, whileRhizoctonia solaniandFusarium solaniwere less inhibited. CuPhi had the highest antimicrobial activity against the four pathogens analysed, and CaPhi and KPhi showed similar antimicrobial activities. Inhibitions by CuPhi and CaPhi could be partially explained by acidification of the media. However, results obtained with KPhi demonstrated that the phosphite anion has antimicrobial activity itself. The increase in ionic strength after Phi addition was not important in the antimicrobial activity of Phi. The activity of phosphites on germination ofF. solanispores showed to be fungistatic rather than fungicidal.
  • Artículo
    Acceso Abierto
    Are Oxidative Stress Biomarkers Sensitive to Environmental Concentrations of Chlorpyrifos Exposed to the Freshwater Crab, Zilchiopsis collastinensis (Decapoda; Trichodactylidae)?
    (2019) Negro, C. L.; Iturburu, F. G.; Mendieta, Julieta Renée; Menone, M. L.; Collins, P.
    Global trends in pesticide use can increase aquatic pollution and affect resident fisheries. Crabs exposed to organophosphate pesticides, such as chlorpyrifos, may increase production of reactive oxygen species (ROS), affecting the pro-oxidant/antioxidant balance. Zichiopsis collastinensis crabs were exposed to environmentally relevant concentrations of chlorpyrifos (0.1 and 0.5 μg L− 1). Effects on the oxidative stress enzymes catalase, superoxide dismutase, glutathione S-transferases, glutathione reductase, and on thiobarbituric acid reactive substances and hydrogen peroxide concentrations were evaluated at four intervals during 96 h exposures. Exposures caused decreased GST activity and increased H2O2 levels in gills. There were modifications of GST, CAT and SOD activities in the hepatopancreas after 12 h of exposure, and an increase of H2O2 levels at every exposure interval observed. The present study proved that chlorpyrifos lead to oxidative stress in Z. collastinensis. However other enzymatic/non-enzymatic responses should be further investigated in order to be included as part of a battery of biomarkers, together with H2O2 levels, which is a parameter highly recommended to be taken into account.
  • Artículo
    Acceso Abierto
    BABA effects on the behaviour of potato cultivars infected by Phytophthora infestans and Fusarium solani
    (2009) Olivieri, F.P; González Altamiranda, E.; Lobato, M.C.; Huarte, M.A.; Daleo, Gustavo Raúl; Guevara, M.G.; Andreu, A.B.
    Since most plants possess resistance mechanisms which can be induced upon pre-treatment with a variety of chemical compounds, the use of β-aminobutyric acid (BABA) as a defence inducer without reported toxic effect on the environment was studied. The aim of this work was to analyse the effectiveness of BABA to induce resistance againstPhytophthora infestansandFusarium solaniin potato cultivars differing in their level of resistance to late blight. The behaviour of some components of biochemical mechanisms by which BABA increases resistance againstP. infestans, as well as the effect of BABA on the activity of a potential pathogenic factor ofF. solani, were studied. Plants with four applications of BABA throughout the crop cycle produced tubers more resistant toP. infestansandF. solanithan non-treated plants. In addition, tuber slices from treated plants, inoculated withP. infestans,showed an increase in phenol and phytoalexin content. The aspartyl proteaseStAP1 accumulation was also higher in tubers obtained from treated plants and inoculated withP. infestans. This result was observed only in the more resistant potato cv. Pampeana, early after infection. In the potato–F. solaniinteraction, infected tubers coming from BABA-treated plants showed minor fungal proteolytic activity than infected, non-treated ones. For potato cvs Pampeana and Bintje, the BABA treatment improved the yield of harvested tubers. The number of tubers per plant and total weight of harvested tubers was greater for those obtained from treated plants with two early or four applications of BABA. The results show that the BABA treatment increases the resistance of potatoes but the degree of increase depends on the original level of resistance present in each cultivar.
  • Artículo
    Embargado
    Calcium-dependent Protein Kinases are Involved in Potato Signal Transduction.
    (2008) Blanco, F.A.; Zanetti, M.E.; Daleo, Gustavo Raúl
    Plant response to pathogens involves an intricate network of signal transduction pathways. Here, potato cell cultures were used to study signal transduction in response to elicitors fromPhytophthora infestans. Pretreatment of cells with Ser/Thr protein kinase inhibitors, EGTA, calmodulin antagonists or a channel blocker abolished the induction of two enzymes involved in defence responses, phenylalanine ammonia-lyase (PAL) and peroxidase. Phosphatase inhibitors caused an increase of these activities in the absence of elicitors. Hyphal cell wall components (HWC) from an incompatible race (HWC 0) produced a rapid and transient increment of histone phosphorylation, whereas induction by HWC from a compatible race (HWC C) was less pronounced and more sustained. As activities were calcium-dependent, a fraction enriched in calcium-dependent protein kinases (CDPKs) was obtained by DEAE chromatography. Fractions from HWC 0- and HWC C-treated cells presented higher kinase activity than that from untreated cells. Moreover, total activity was higher in the incompatible than in the compatible interaction. Activity was calcium-dependent, partially inhibited by calmodulin antagonists and able to phosphorylate syntide-2, a specific substrate of CDPKs. An in-gel kinase assay showed the presence of a band of approximately 50kDa whose activity was higher in HWC 0- than in HWC C-treated cells and was not detected in control extracts. This report presents evidences of the differential activation of CDPKs in response to elicitors from different races ofP. infestans, revealing that these protein kinases participate in the defence response to oomycete.
  • Artículo
    Acceso Abierto
    Characterization of biodegradable/non-compostable films made from cellulose acetate/corn starch blends processed under reactive extrusion conditions
    (2019) Herniou–Julien, Clémence; Mendieta, Julieta Renée; Gutiérrez, Tomy J.
    The manufacture of food packaging materials from food hydrocolloids has been widely studied during the last decades and multiple alternatives have been investigated, with research mainly focusing on improving the physicochemical and mechanical properties of the different materials. Processing food hydrocolloids by reactive extrusion (REx) for the development of food packaging has, however, been poorly studied. Four film systems were prepared from corn (Zea mays) thermoplastic starch (TPS) containing either cellulose acetate (C) or chromium octanoate (Cat - a potential food grade catalyst), or a blend of both (C + Cat). Processing was done under REx conditions using a twin-screw extruder. An exhaustive study of the resulting materials was carried out in terms of the structural, physicochemical, thermal, surface, mechanical and compostable properties related to their potential use in food packaging applications. The most hydrophobic material was the C-containing film. However, this physicochemical behavior was different on the film surface, thus suggesting molecular rearrangements within the material. The Cat-containing films were darker than the other materials. The mechanical behavior observed in the Cat-containing films was particularly interesting as it suggests that these film systems could be used as shape memory materials for food packaging applications, as long as the following mechanical conditions are not exceeded: 5.02% strain and 0.43 MPa stress. All the films tested were biodegradable. We confirmed that Cat-containing film systems produced non-compostable materials at high concentrations (1 mg/mL), as measured by its effect on lettuce seedlings. This confirms that biodegradable materials are not necessarily compostable.
  • Parte de libro
    Acceso Abierto
    Chitosan as Source for Pesticide Formulations
    (IntechOpen, 2017) Ippólito, Sebastián D.; Mendieta, Julieta Renée; Terrile, María C.; Tonon, Claudia Virginia; Mansilla, Andrea Y.; Colman, Silvana; Albertengo, Liliana; Rodríguez, María S.; Casalongué, Claudia A.
    Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium solani f. sp. eumartii, respectively, are severe diseases in Solanaceae crops worldwide. Although traditional approaches to control plant diseases have mainly relied on toxic chemical compounds, current studies are focused to identify more sustainable options. Finding alternatives, a low molecular weight chitosan (LMWCh) obtained from biomass of Argentine Sea’s crustaceans was assayed. In an attempt to characterize the action of LMWCh alone or in combination with the synthetic fungicide Mancozeb, the antimicrobial properties of LMWCh were assayed. In a side-by-side comparison with the SYTOX Green nucleic acid stain and the nitric oxide–specific probe, diaminofluorescein‐ FM diacetate (DAF-FM DA), yielded a similar tendency, revealing LMWChmediated cell death. The efficacy of LMWCh, Mancozeb, and the mixture LMWCh– Mancozeb was in turn tested. A synergistic effect in the reduction of F. eumartii spore germination was measured in the presence of subinhibitory dosis of 0.025 mg ml−1 LMWCh and 0.008 mg ml−1 Mancozeb. This mixture was efficient to increase the effectiveness of the single treatments in protecting against biotic stress judged by a drastic reduction of lesion area in P. infestans–inoculated tissues and activation of the potato defense responses.
  • Artículo
    Acceso Abierto
    Cytotoxic effect of potato aspartic proteases (StAPs) on Jurkat T cells
    (2010) Mendieta, Julieta Renée; Fimognari, Carmela; Daleo, Gustavo Raúl; Hrelia, Patrizia; Guevara, María G.
    StAPs are potato aspartic proteases with cytotoxic activity against plant pathogens and spermatozoa.StAPs cytotoxic activity is selective, since these proteins do not exert toxic effect on plant cells and erythrocytes. In this work, we investigated the capacity ofStAPs to exert cytotoxicity on human leukaemia cells. Obtained results show thatStAPs induce apoptosis on Jurkat T cells after a short time of incubation in a dose-dependent manner. However, no significative effect on the T lymphocytes viability was observed at allStAPs incubation times and concentrations tested. These results suggest thatStAPs can be conceptually promising leads for cancer therapy.
  • Documento de conferencia
    Acceso Abierto
    Expression of plant specific domain of potato aspartic proteases (StAP-PSI) restricts P. infestans spread in potato leaves.
    (2015) Frey, María Eugenia; Pepe, Alfonso; Daleo, Gustavo Raúl; Guevara, María Gabriela
    Plant specific insert (PSI) is a domain present in the precursors and mature atypical plant aspartic proteases (APs). Several plant APs have been associated with the plant mechanism of defence against pathogens. However, only two (StAP1 and StAP3, for Solanum tuberosum APs) of these proteases, contain the PSI domain into the mature form. We have previously reported the cytotoxic activity of the recombinant StAP-PSI towards plant pathogens. However the role of PSI domain of StAPs in the plant mechanism defense is still unknown. The aim of this work was to analyze the effect of transient expression of StAP-PSI in potato leaves infected by P. infestans. Results obtained show that StAP-PSI expression reduces the P. infestans affected area in a 60 % compared with the control ones. Analysis by qPCR shows an increase of the transcript level of the hypersensitive response marker (hsr203J) in potato leaves that express StAP-PSI, independent of the P. infestans infection; however the highest increase of this gene was detected in leaves at 6 h. after infection. Additionally, an increase of the WRKI1 transcript level was detected in potato leaves that express StAP-PSI. Results obtained here indicate that, PSI domain of StAPs could have a direct (as antimicrobial compound) and indirect (as an inductor molecule) role in the plant mechanism to restrict the pathogen spread.
  • Artículo
    Acceso Abierto
    Fibrin(ogen)olytic and antiplatelet activities of a subtilisin-like protease from Solanum tuberosum (StSBTc-3)
    (2016) Pepe, Alfonso; Frey, María Eugenia; Muñoz, Fernando; Fernández, María Belén; Pedraza, Anabela; Galbán, Gustavo; García, Diana Noemí; Daleo, Gustavo Raúl; Guevara, María Gabriela
    Plant serine proteases have been widely used in food science and technology as well as in medicine. In this sense, several plant serine proteases have been proposed as potential anti-coagulants and antiplatelet agents. Previously, we have reported the purification and identification of a plant serine protease from Solanum tuberosum leaves. This potato enzyme, named as StSBTc-3, has a molecular weight of 72 kDa and it was characterized as a subtilisin like protease. In this work we determine and characterize the biochemical and medicinal properties of StSBTc-3. Results obtained show that, like the reported to other plant serine proteases, StSBTc-3 is able to degrade all chains of human fibrinogen and to produces fibrin clot lysis in a dose dependent manner. The enzyme efficiently hydrolyzes b subunit followed by partially hydrolyzed a and g subunits of human fibrinogen. Assays performed to determine StSBTc-3 substrate specificity using oxidized insulin b-chain as substrate, show seven cleavage sites: Asn3-Gln4; Cys7-Gly8; Glu13-Ala14; Leu15-Tyr16; Tyr16-Leu17; Arg22-Gly23 and Phe25-Tyr26, all of them were previously reported for other serine proteases with fibrinogenolytic activity. The maximum StSBTc-3 fibrinogenolytic activity was determined at pH 8.0 and at 37 C. Additionally, we demonstrate that StSBTc- 3 is able to inhibit platelet aggregation and is unable to exert cytotoxic activity on human erythrocytes in vitro at all concentrations assayed. These results suggest that StSBTc-3 could be evaluated as a new agent to be used in the treatment of thromboembolic disorders such as strokes, pulmonary embolism and deep vein thrombosis.
  • Parte de libro
    Acceso Abierto
    Hidrolizados proteicos de pescado a partir de residuos de la industria pesquera con potencialidad en Biotecnología
    (2016) Massa, Agueda E.; Manca, Emilio A.; Mansilla, Andrea Yamila; Mendieta, Julieta Renée; Casalongué, Claudia A.
    Durante las operaciones pesqueras destinadas al procesamiento de pescados y mariscos para consumo humano, se generan residuos (cabezas, vísceras, piel y espinas) que constituyen más del 40% del peso total de los desembarques pesqueros. Estos subproductos presentan compuestos con importantes propiedades nutricionales, funcionales y bioactivas que pueden ser utilizados en diversos sectores industriales. El objetivo del presente estudio fue elaborar hidrolizados proteicos a partir de residuos pesqueros y evaluar su aplicabilidad en la industria agrícola. La materia prima, que fue obtenida de industrias pesqueras marplatenses, se homogeneizó y se sometió a una hidrólisis enzimática. Finalizado dicho proceso, el hidrolizado proteico fue separado y caracterizado químicamente. La composición química de estos productos incluyó compuestos orgánicos (péptidos aminoácidos libres, ácidos grasos omega-3, vitaminas) y minerales (nitrógeno, fósforo, potasio, calcio, magnesio y otros oligoelementos) altamente nutritivos para las plantas y microorganismos beneficiosos. En este contexto, el desarrollo de hidrolizados proteicos de pescado puede considerarse como una alternativa económicamente viable y ecológicamente sustentable con un alto potencial de aplicación biotecnológica.
  • Artículo
    Acceso Abierto
    Hydrogen-bonding interactions and compostability of bionanocomposite films prepared from corn starch and nano-fillers with and without added Jamaica flower extract
    (2018) Gutiérrez, Tomy J.; Toro-Márquez,Luis A.; Merino, Danila; Mendieta, Julieta Renée
    Bionanocomposite films processed by twin screw extrusion followed by thermo molding were prepared from corn starch (Zea mays) and pH-sensitive nano-clays packaged with Jamaica flower (Hibiscus sabdariffa) extract (JFE). The hydrogen (H)-bonding interactions of the materials obtained were evaluated by ATR/FTIR spectroscopy, and their influence on the physicochemical and surface properties of the materials was analyzed. The degree of biodegradability and compostability of the films was also recorded. This latter was analyzed in terms of the ecotoxicity of the films using the variations in the growth of the primary root of lettuce (Lactuca sativa) seedlings exposed to three concentrations (1, 10 and 100 μg/mL) of the powdered films as a biomarker. The addition of the JFE-containing nano-fillers strengthened the H-bonding interactions with the thermoplastic starch (TPS) matrix, and these interactions were more efficient when there were fewer steric impediments between the JFE and the TPS. Additionally, stronger H-bonding interactions produced more hydrophilic surfaces, with greater surface energy and rougher surface morphology. All the films tested were biodegradable. Our research group had previously encountered high cytotoxicity in one of the evaluated nano-clay systems, and in this study, we confirmed that this same nano-clay system produced a non-compostable material at high concentrations (100 μg/mL), as measured by its effect on lettuce seedlings. This confirms that biodegradable materials are not necessarily compostable.
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Daleo, Gustavo Raúl (2011-2012)
    (2012) Daleo, Gustavo Raúl
    Se estudia, en forma integrada, los diferentes mecanismos de defensa frente a patógenos desarrollados por la planta de papa a partir del tratamiento con inductores, organismos biocontroladores o agentes químicos no contaminantes. Se pretende contribuir al conocimiento básico de estos mecanismos y al diseño de estrategias de control basadas en procesos naturales, en lugar de depender, casi exclusivamente, de agentes químicos costosos y contaminantes. Además, se ha comenzado a estudiar los efectos de ciertos componentes de la respuesta de defensa de las plantas de papa sobre microorganismos patógenos humanos, espermatozoides y sobre células tumorales, abriéndose así una línea de posibles aplicaciones terapéuticas.
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Daleo, Gustavo Raúl (2013-2014)
    (2014) Daleo, Gustavo Raúl
    Se estudian, en forma integrada, los diferentes mecanismos de defensa frente a patógenos desarrollados por la planta de papa a partir del tratamiento con inductores, organismos biocontroladores o agentes químicos no contaminantes. Se pretende contribuir al conocimiento básico de estos mecanismos y al diseño de estrategias de control basadas en procesos naturales, en lugar de depender, casi exclusivamente, de agentes químicos costosos y contaminantes. Además, se ha comenzado a estudiar los efectos de ciertos componentes de la respuesta de defensa de las plantas de papa sobre microorganismos patógenos humanos, espermatozoides y sobre células tumorales, abriéndose así una línea de posibles aplicaciones terapéuticas. A-Con respecto al estudio de mecanismos de defensa de la papa contra patógenos, se ha profundizado en el estudio del inhibidor de serin proteasas (PLPKI) que muestra especificidad hacia proteasas microbianas. Se lo ha secuenciado y comprobado su actividad inhibitoria sobre proteasas de dos patógenos de la papa, P. infestans y R. solani. Además, la actividad en distintos cultivares y clones de papa se correlaicona con el grado de resistencia horizontal de dichos clones, de modo que podría utilizarse como marcador de resistencia (7.1.1). Se continuó el estudio de los fosfitos como estimuladores de las reacciones de defensa de la papa frente a diversos tipos de estrés. Se comprobó que la plantas tratadas con CaPhi resisten mejor el déficit hídrico y se recuperan más rápido luego de irrigación; muestran además cambios anatómicos y fisiológicos coherentes con este mejor comportamiento ante el estrés hídrico (7.5.1). En el mismo sentido, las plantas tratadas con KPhi exhibieron incrementos en la expresión de genes vinculados a la resistencia a la radiación UV-B (7.5.2, 7.5.3). B- Se ha avanzado en el estudio del mecanismo por el cual el Inserto Específico de Plantas incluido en Aspartil Proteasas de papa (StAsp-PSI) desestabiliza membranas de células microbianas y tumorales. Los resultados muestran que en el proceso intervienen la difusión lateral previa a la agregación del PSI y formación de poros. Esta agregación viene precedida por cambios conformacionales y la penetración en bicapas fosfolipídicasse produce principalmente en presencia de fosfolípidos negativamente cargados (7.1.3). La ya informada actividad citotóxica de las Aspartil Proteasas de papa sobre células de patógenos y célula tumorales hacen que estas proteínas puedan utilizarse como agentes terapéuticos. Con esta perspectiva, se conjugó StAP3 con polietilen glicol (PEG) y se estudiaron sus propiedades comparadas con las de la proteína nativa, comprobándose que que la actividad antifúngica se incrementaba, sin modificar la selectividad, puesto que no mostró ctividad hemolítica. Dado que este tipo de derivatización mejora propiedades farmacocinéticas y farmacodinámicas de potenciales agentes terapéuticos, estos resultados constituyen un avance hacia la posible aplicación de estas proteínas en este sentido (7.1.2). Por último, se ha caracterizado la proteína de papa con actividad de caspasa 3 en cuanto a masa molecular, carácter monomérico y secuenciación, que reveló identidad de secuencia con una proteína de papa tipo subtilisina, razón por la cual se la nombró StSBTc-3. Con respecto a su función en la interacción con patógenos, se mostró que se comporta como caspasa ejecutora durante la interacción con P. infestans, contribuyendo a restringir la diseminación del patógeno (7.2.1, 7.5.4). Se avanzó en su caracterización funcional, mostrando que ejerce regulación positiva sobre genes marcadores de la vía de señalización de salicílico (SA) y que actuaría corriente abajo o en forma independeiente de la vía del etileno/jasmónico (7.5.6). Se ha reportado además una serin proteasa de papa con actividad anticoagulante y fibrinogenolítica con posibles aplicaciones biotecnológicas (7.5.5).
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Mendieta, Julieta Renée (2013)
    (2013) Mendieta, Julieta Renée
    A continuación se expone la labor desarrollada en el periodo enero-diciembre 2013. Cabe destacar que dicha labor se compone de dos proyectos de investigación: uno correspondiente a un proyecto de ciencia básica con posible aplicación a mediano/largo plazo correspondiente al plan de investigación con el cual ingresé a la CIC como investigadora asistente y un segundo proyecto de tipo I+D llevado a cabo de forma paralela en colaboración con la Dra. Casalongué. -Título de proyecto presentado para ingreso a carrera CIC: Aplicaciones biotecnológicas del inhibidor de proteasas tipo germina (IPG). Análisis de su actividad antimicrobiana y antitumoral. -Título del tema investigado: Estudio de las propiedades antimicrobianas y los efectos sobre células de mamíferos del Inhibidor de Tripsina tipo Germina de Trigo (IPG). -Objetivo General: Analizar las propiedades antimicrobianas de la proteína IPG sobre patógenos vegetales y evaluar sus efectos sobre cultivos de células de mamíferos.
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Mendieta, Julieta Renée (2014)
    (2014) Mendieta, Julieta Renée
    A continuación se expone la labor desarrollada en el periodo enero-diciembre 2014. Cabe destacar que dicha labor se compone de dos proyectos de investigación: uno correspondiente a un proyecto de ciencia básica con posible aplicación a mediano/largo plazo correspondiente al plan de investigación con el cual ingresé a la CIC como investigadora asistente y un segundo proyecto de tipo I+D llevado a cabo de forma paralela en colaboración con la Dra. Casalongué. -Título de proyecto presentado para ingreso a carrera CIC: Aplicaciones biotecnológicas del inhibidor de proteasas tipo germina (IPG). Análisis de su actividad antimicrobiana y antitumoral -Título del tema investigado: Estudio de las propiedades antimicrobianas y los efectos sobre células de mamíferos del Inhibidor de Tripsina tipo Germina de Trigo (IPG) -Objetivo General: Analizar las propiedades antimicrobianas de la proteína IPG recombinante, analizar su rol bajo condiciones de estrés y evaluar su potencialidad en aplicaciones nanobiotecnológicas. - Inhibidor de proteasas tipo germina de trigo (IPG) El Inhibidor de Proteasas tipo Germina (IPG) es un inhibidor de tripsina que se aisló en nuestro laboratorio a partir del fluido extracelular de hojas de trigo y su segmento N-terminal resultó ser homólogo a una Germin-like Protein (GLP). Este inhibidor presenta además, otras actividades enzimáticas como superóxido dismutasa (SOD) y actividad de adenosina difosfato glucosa pirofosfatasa (AGPP), caracterizando a esta proteína como una proteína multifuncional. Estas características multifuncionales, han permitido caracterizar a IPG como una proteína antimicrobiana (objetivo presentado en informes anteriores). Con el propósito de avanzar en el proyecto de investigación se han planteado los siguientes objetivos: -Objetivo 1: Producir en forma recombinante la IPG de trigo (IPGr) (este objetivo fue informado parcialmente en el informe anterior y ha sido completado este período). -Objetivo 2: Analizar in vitro el efecto antifúngico del IPGr sobre esporas de F. solani, comparativamente con IPG (este objetivo fue informado parcialmente en el informe anterior y ha sido completado este período). -Objetivo 3: Analizar la capacidad de la proteína IPG de proteger a las plantas del ataque de patógenos vegetales (objetivo desarrollado en este período). -Objetivo 4: Analizar el efecto del estrés salino sobre la proteína IPG en plántulas de trigo. -Objetivo 5: Desarrollar nanoarcillas compuestas incorporando a la proteína IPG para evaluar sus potenciales biotecnológicas (objetivo desarrollado en este período).
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Mendieta, Julieta Renée (2015)
    (2015) Mendieta, Julieta Renée
    A continuación se expone la labor desarrollada en el periodo enero-diciembre 2015. Cabe destacar que dicha labor se compone de dos proyectos de investigación: uno correspondiente a un proyecto de ciencia básica con posible aplicación a mediano/largo plazo correspondiente al plan de investigación con el cual ingresé a la CIC como investigadora asistente y un segundo proyecto de tipo I+D llevado a cabo de forma paralela realizado dentro de un proyecto mayor dirigido por la Dra. Casalongué. Título de proyecto presentado para ingreso a carrera CIC: Aplicaciones biotecnológicas del inhibidor de proteasas tipo germina (IPG). Análisis de su actividad antimicrobiana y antitumoral Título del tema investigado: Estudio de las propiedades de IPG sobre células de mamíferos. Objetivo General: Analizar las propiedades de IPG sobre cultivo de células de mamíferos. - Inhibidor de proteasas tipo germina de trigo (IPG) El Inhibidor de Proteasas tipo Germina (IPG) es un inhibidor de tripsina que se aisló en nuestro laboratorio a partir del fluido extracelular de hojas de trigo y su segmento N-terminal resultó ser homólogo a una Germin-like Protein (GLP). Este inhibidor presenta además, otras actividades enzimáticas como superóxido dismutasa (SOD) y actividad de adenosina difosfato glucosa pirofosfatasa (AGPP), caracterizando a esta proteína como una proteína multifuncional. Estas características multifuncionales, han permitido caracterizar a IPG como una proteína antimicrobiana (objetivo presentado en informes anteriores). Con el propósito de avanzar en el proyecto de investigación se han planteado los siguientes objetivos: OBJETIVO 1: Analizar los efectos biológicos de IPG sobre células de mamíferos. OBJETIVO 2: Desarrollar nanoarcillas compuestas incorporando a la proteína IPG como modelo para aplicaciones biotecnológicas. Se han realizado experimentos en el marco de un proyecto en colaboración con la Dra. Casalongué (directora del grupo de investigación “Fisiología del estrés en plantas” del IIB-UE-CONICET-Universidad Nacional de Mar del Plata). La Dra. Casalongué se encuentra desarrollando un proyecto ANPCyT PICT-Bicentenario 0746 sobre Temas Prioritarios de Impacto Regional denominado “Valoración de deshechos pesqueros para la obtención de derivados de quitina y su aplicación como compuestos bioactivos en plantas”. La colaboración con nuestro grupo se estableció por el interés de evaluar el efecto de los quitosanos, compuestos inocuos, biodegradable y con un gran potencial de aplicación en el campo de la agronomía, sobre el trigo, un cultivo de sumo interés agronómico en nuestra región. Los resultados hasta el momento son prometedores ya que indican que el tratamiento con quitosano de las semillas de trigo, acelera significativamente la germinación y potencian el crecimiento de plántulas de trigo.
  • Informe de investigador
    Acceso Abierto
    Informe científico de investigador: Mendieta, Julieta Renée (2016-2017)
    (2017) Mendieta, Julieta Renée
    En nuestro laboratorio se purificó un inhibidor de serina proteasas homólogo a una Germin Like-Protein (GLP) a partir del fluído intercelular de hojas de trigo, al que se denominó Inhibidor de Proteasas Tipo Germina (IPG). Además de actividad de inhibidor de proteasas, IPG posee actividades de superóxido dismutasa (SOD) y adenosina difosfato glucosa pirofosfatasa, lo cual lo convierte en una proteína multifuncional. En este período se ha estudiados el efecto de IPG sobre la formación de biofilms tanto de microrganismos fitopatógenos como benéficos de plantas. Los resultados obtenidos permiten proponer a la proteína IPG como un potencial candidato para la aplicación en agricultura. Por otra parte se desarrolla un proyecto tendiente a evaluar los efectos de los quitosanos, compuestos obtenidos de los desechos de la industria pesquera de la costa de la Prov. de BA sobre microorganismos patógenos de cultivos de interés.
  • Artículo
    Acceso Abierto
    An integrated biomarker response study explains more than the sum of the parts: Oxidative stress in the fish Australoheros facetus exposed to imidacloprid
    (2018) Iturburu, Fernando G.; Bertrand, Lidwina; Mendieta, Julieta Renée; Amé, María V.; Menone, Mirta L.
    Integrated Biomarkers Response (IBR) index have been developed as a practical and robust tool to assess the susceptibility to pollutants using multiple biomarker responses. Neonicotinoid insecticides are nowadays one of the most sold pesticides worldwide. Nevertheless, imidacloprid (IMI) sub-lethal effects such as oxidative stress (OS) on fishes are scarcely studied. Hence, the aims of this work were: (1) to evaluate exposure- and damage biomarkers related to OS in the freshwater fish Australoheros facetus exposed to IMI and (2) to apply the IBR index to achieve a comprehensive understanding of OS in the fish. The results of the present study showed that all the biomarkers presented different responses in the three monitored tissues: liver, brain and gills. Results for an initial battery of 19 biomarkers were obtained and for the IBR index only those with significant differences have been considered. The biomarkers that had the most important weight on the IBR index were SOD activity in brain and gills, H2O2 concentration in liver, and carbonyl groups concentration in gills in fishes exposed to 100 and 1000 μg L−1 IMI. This index allowed affirming that a short term exposure to environmentally relevant concentrations of IMI (≥10 μg L−1) produces OS in A. facetus. However, a more deep understanding of some biomarkers response is necessary to improve the index and for finally apply it in field studies.
  • Artículo
    Acceso Abierto
    Isolation and characterization of a Solanum tuberosum subtilisin-like protein with caspase-3 activity (StSBTc-3)
    (2015) Fernandez, María Belén; Daleo, Gustavo Raúl; GuevaRA, María Gabriela
    Plant proteases with caspase-like enzymatic activity have been widely studied during the last decade. Previously, we have reported the presence and induction of caspase-3 like activity in the apoplast of potato leaves during Solanum tuberosum- Phytophthora infestans interaction. In this work we have purified and identified a potato extracellular protease with caspase-3 like enzymatic activity from potato leaves infected with P. infestans. Results obtained from the size exclusion chromatography show that the isolated protease is a monomeric enzyme with an estimated molecular weight of 70 kDa approximately. Purified protease was analyzed by MALDI-TOF MS, showing a 100% of sequence identity with the deduced amino acid sequence of a putative subtilisin-like protease from S. tuberosum (Solgenomics protein ID: PGSC0003DMP400018521). For this reason the isolated protease was named as StSBTc-3. This report constitutes the first evidence of isolation and identification of a plant subtilisin-like protease with caspase-3 like enzymatic activity. In order to elucidate the possible function of StSBTc-3 during plant pathogen interaction, we demonstrate that like animal caspase-3, StSBTc-3 is able to produce in vitro cytoplasm shrinkage in plant cells and to induce plant cell death. This result suggest that, StSBTc-3 could exert a caspase executer function during potato- P. infestans interaction, resulting in the restriction of the pathogen spread during plantepathogen interaction.
  • Parte de libro
    Embargado
    Isolation of a New Antimicrobial/Antitumor Plant Peptide: Biotechnology Prospects for its Use in Cancer and Infectious Diseases Therapies
    (2011) Guevara, M.G.; Muñoz, F.F.; Fernández, M.B; Mendieta, Julieta Renée; Daleo, Gustavo Raúl
    The immune system of multi-cellular organisms comprises a vast arsenal of mechanisms to protect the host from the continuous interactions with infectious microorganisms. Antimicrobial peptides (AMPs) are peptides which protect their hosts against a vast array of microorganisms. These peptides are produced by several species including bacteria, insects, plants, vertebrates and they have been recognized as ancient evolved molecules that have been effectively preserved in mammals. AMPs are expressed on the primary barriers of the organism such as skin and mucosal epithelia, preventing the colonization of host tissues by pathogens. We have previously reported the induction after infection and the cytotoxic activity of potato aspartic proteases (StAPs) towards plant pathogens. Here we show results on the antimicrobial/antitumor activities of these enzymes and of a domain of these enzymes named as StAsp-PSI. StAsp-PSI has structural homology with a family of proteins with antimicrobial/antitumor activity named as SAPLIPs family. Ours results show that StAsp-PSI is able to kill spores of two potato pathogens but not plant cells, in a dose dependent manner. As reported for StAPs (Solanum tuberosum aspartic proteases), StAsp-PSI ability to kill microbial pathogens is dependent on the direct interaction of the protein with the microbial cell wall/or membrane, leading to increased permeability and lysis. Additionally, we demonstrated that, like proteins of SAPLIP family, StAsp-PSI and StAPs are cytotoxic for Gram negative and Gram positive bacteria in a dose dependent manner. The amino acid residues conserved in SP_B (pulmonary surfactant protein B) and StAsp-PSI could explain the cytotoxic activity exerted by StAsp-PSI and StAPs against Gram positive bacteria. On the other hand, results obtained show that StAPs induce apoptosis on Jurkat T cells at short time of incubation in a dose dependent manner. However, not significative effect on the T lymphocytes viability was observed at any time and StAPs concentration assay. StAsp-PSI was able to induce DNA fragmentation, ROS induction and cell cytotoxicity on human breast cancer cells in a dose dependent manner. These results open a new perspective to test these proteins as possible candidates to develop new drugs that would be active against microbes but not against mammalian cells and considerer these proteins as conceptually promising agent in cancer therapy.