Los científicos del futuro están en la escuela

El proyecto de extensión universitaria “Los Científicos del Futuro están en la Escuela” se encuentra acreditado desde el año 2004 por la Facultad de Ciencias Exactas de la UNLP. El mismo propone la divulgación, la promoción del interés por la ciencia y la tecnología, y la complementación de la enseñanza de ciencias naturales a nivel primario.Centro de Investigación y Desarrollo en Ciencias Aplicada

Los científicos del futuro están en la escuela

El proyecto de extensión universitaria “Los Científicos del Futuro están en la Escuela” se encuentra acreditado desde el año 2004 por la Facultad de Ciencias Exactas de la UNLP. El mismo propone la divulgación, la promoción del interés por la ciencia y la tecnología, y la complementación de la enseñanza de ciencias naturales a nivel primario.Centro de Investigación y Desarrollo en Ciencias Aplicada

Riboflavin induces Metarhizium spp. to produce conidia with elevated tolerance to UV-B, and upregulates photolyases, laccases and polyketide synthases genes

Aims: The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). Methods and Results: Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866·7 mW m−2 of UV-B Quaite-weighted irradiance to total doses of 3·9 or 6·24 kJ m−2. Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. Conclusions: Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. Significance and Impact of the Study: The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs.Fil: Pereira-Junior, R.A.. Universidade Federal de Goiás; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Huarte Bonnet, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidade Federal de Goiás; BrasilFil: Paixão, F.R.S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidade Federal de Goiás; BrasilFil: Roberts, D.W.. State University of Utah; Estados UnidosFil: Luz, C.. Universidade Federal de Goiás; BrasilFil: Pedrini, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Fernandes, É.K.K.. Universidade Federal de Goiás; Brasi

Alkane-grown <i>Beauveria bassiana</i> produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations

The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle hydrocarbons as the sole carbon source, inducing several enzymes involved in alkane assimilation and concomitantly increasing virulence against insect hosts. In this study, we describe some physiological and molecular processes implicated in growth, nutritional stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology was investigated using light and transmission electron microscopy (TEM) while the surface topography was examined using atomic force microscopy (AFM). Fungal hydrophobicity was also measured on the cell surface. Additionally, the expression pattern of several genes associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to mycelial pellets described in other alkane-free fungi, which were able to germinate and produce viable conidia in media without a carbon source and to be pathogenic against larvae of the beetles Tenebrio molitor and Tribolium castaneum. Optical microscopy and TEM showed that pellets were formed by hyphae cumulates with high peroxidase activity, exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown conidia appeared to be more hydrophobic and cell surfaces displayed different topography than glucose-grown cells, as it was observed by AFM. We also found a significant induction in several genes encoding for peroxins, catalases, superoxide dismutases, and hydrophobins. These results show that both morphological and metabolic changes are triggered in mycelial pellets derived from alkane-grown B. bassiana.Instituto de Investigaciones Bioquímicas de La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Puesta en valor de la extensión universitaria: curricularización para una integración real con investigación y docencia

This work is presented as the result of a complex, continuum and long reflexive process about our teaching practices along different workshops, meetings and collaborative exchanges in our teaching formation journey. The text includes our revisions about educational fragmentation and the importance of an integral, social and collectively constructed professional formation. We consider the importance of the articulation between teaching, research and extension practices for the social, political and historically situated teaching and learning processes, which promote a professional profile more committed to political-social problems, and we place the University as a fundamental institutional actor in the permanent exchange with the community. We also include concrete proposals for curricularisation of extension as an innovative pedagogical strategy to implement in university teaching practices in response to the problems addressed.Este trabajo se origina en respuesta a un proceso reflexivo complejo y continuo de nuestras prácticas docentes a lo largo de distintos encuentros, talleres e intercambios de la especialización en docencia universitaria de la Universidad Nacional de La Plata. A lo largo del texto plasmamos nuestras revisiones sobre la fragmentación en la educación y la necesidad de una formación integral, social y colectivamente construida. Consideramos la importancia de la articulación entre docencia, investigación y extensión para los procesos de enseñanza y aprendizaje social, política e históricamente situados, que promuevan un perfil profesional y ciudadano más comprometido con las problemáticas político-sociales, y situamos a la Universidad como actor institucional fundamental en el intercambio permanente con la comunidad. Incluimos también propuestas concretas de curricularización de la extensión como estrategia pedagógica innovadora para implementar en las prácticas docentes universitarias en respuesta a las problematizaciones abordadas

Metarhizium robertsii and M. acridum conidia produced on riboflavin-supplemented medium have increased UV-A tolerance and upregulated photoprotection and photoreactivation genes

The aim of this study was to evaluate the effect of riboflavin supplementation of culture medium on conidial UV-A tolerance of M. acridum (Driver & Milner) (Hypocreales: Clavicipitaceae) and M. robertsii (Bischoff, Rehner & Humber) (Hypocreales: Clavicipitaceae). These fungi were produced on culture medium supplemented, or not supplemented, with riboflavin. Relative germination and expression patterns of some photoprotection-related genes were evaluated after irradiating with artificial UV-A, or with filtered solar radiation (> 320 nm; UV-A and visible radiation). M. acridum conidia harvested from riboflavin-supplemented culture medium demonstrated enhanced UV-A tolerance when irradiated with artificial UV-A. Nevertheless, relative germination of conidia of both species produced on riboflavin-supplemented medium and exposed to filtered solar radiation was significantly higher than those produced on medium not supplemented with riboflavin. Riboflavin increased the transcription of photolyases, laccases and polyketide synthase genes. However, each fungal species induced different genes patterns involved in DNA repair and photoprotection. The addition of riboflavin to the substrate used for mass production of Metarhizium spp. and the resulting enhancement of conidial tolerance to solar radiation may improve the effectiveness of these fungi in biological control programs.Instituto de Investigaciones Bioquímicas de La Plat