Libros y Capítulos de Libros
URI https://digital.cic.gba.gob.ar/handle/11746/5354
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- Parte de libroAcceso AbiertoValoración biotecnológica de quitina y quitosano para el desarrollo de películas con aplicación en agricultura(2016)La quitina es el polisacárido constitutivo más abundante en los exoesqueletos de insectos y crustáceos. Su derivado más tradicionalmente estudiado es el quitosano. En el presente trabajo se ha propuesto la obtención de quitina y la utilización de quitosano para el desarrollo de películas con potencial uso de aplicación en agricultura. La quitina fue obtenida a partir del desecho de exoesqueletos de langostinos asociados a su comercialización de las industrias pesqueras de la ciudad de Mar del Plata, Argentina. Si bien existen varios métodos de obtención de quitina, en el presente trabajo se utilizó una metodología sencilla en el laboratorio pero de fácil escalonamiento a escala piloto. Esta consistió en un proceso químico de hidrólisis de las proteínas y remoción del material inorgánico utilizando ácidos y álcalis a altas concentraciones pero, a diferencia de la mayoría de los métodos descriptos, el procedimiento se realiza a temperatura ambiente. Para la obtención de películas o filmes se partió de quitosanos de origen comercial y se utilizó la técnica de evaporación de solvente conocida como casting, descripta como altamente práctica y sencilla. Se optimizaron las condiciones para la utilización de dichos filmes en el recubrimiento de semillas de trigo.
- Parte de libroAcceso AbiertoChitosan as Source for Pesticide Formulations(IntechOpen, 2017)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.
- Parte de libroEmbargadoIsolation of a New Antimicrobial/Antitumor Plant Peptide: Biotechnology Prospects for its Use in Cancer and Infectious Diseases Therapies(2011)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.
- Parte de libroAcceso AbiertoStSBTC-3: una serín proteasa de Solanum tuberosum con actividad antiplaquetaria y fibrin(ogen) olítica(Universidad de San Carlos de Guatemala; Universidad Juárez Autónoma de Tabasco, 2016)Las serín proteasas están ampliamente distribuidas y pueden ser encontradas en todos los reinos. Se han propuesto serín proteasas de plantas como agentes anticoagulantes y antiplaquetarios. En el presente trabajo reportamos la actividad fibrinogenolítica y antiplaquetaria de una proteasa del tipo subtilisina de Solanum tuberosum (StSBTc-3), previamente identificada y purificada en nuestro laboratorio. Los resultados obtenidos muestran que StSBTc-3 es capaz de degradar todas las cadenas del fibrinógeno y redisolver el coagulo de fibrina en forma dosis dependiente. También se realizó una caracterización bioquímica de la proteasa en estudio. El pH óptimo para la actividad fibrinogenolítica fue 8 y la temperatura óptima fue de 37 C. StSBTc-3 presentó un amplio rango de actividad en función del pH (5 a 12). En cuanto a la temperatura, presentó actividad entre 30 C 60 C. También se determinaron siete sitios de clivado de la cadena B de la insulina. Se realizaron ensayos para determinar la actividad antiplaquetaria. Estos muestran que StSBTc-3 es capaz de inhibir la agregación plaquetaria. StSBTc-3 no produce hemólisis a las concentraciones utilizadas. Los resultados sugieren que StSBTc-3 puede ser evaluada para ser utilizada en el tratamiento de enfermedades cardiovasculares con desórdenes trombóticos.
- Parte de libroAcceso AbiertoTransient expression of plant specific domain of potato aspartic proteases (Stap-Psi) restricts P. Infestans spread in potato leaves(Universidad de San Carlos de Guatemala; Universidad Juárez Autónoma de Tabasco, 2016)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.