The Progeny of Arabidopsis thaliana Plants Exposed to Salt Exhibit Changes in DNA Methylation, Histone Modifications and Gene Expression

Plants are able to acclimate to new growth conditions on a relatively short time-scale. Recently, we showed that the progeny of plants exposed to various abiotic stresses exhibited changes in genome stability, methylation patterns and stress tolerance. Here, we performed a more detailed analysis of methylation patterns in the progeny of Arabidopsis thaliana (Arabidopsis) plants exposed to 25 and 75 mM sodium chloride. We found that the majority of gene promoters exhibiting changes in methylation were hypermethylated, and this group was overrepresented by regulators of the chromatin structure. The analysis of DNA methylation at gene bodies showed that hypermethylation in the progeny of stressed plants was primarily due to changes in the 5′ and 3′ ends as well as in exons rather than introns. All but one hypermethylated gene tested had lower gene expression. The analysis of histone modifications in the promoters and coding sequences showed that hypermethylation and lower gene expression correlated with the enrichment of H3K9me2 and depletion of H3K9ac histones. Thus, our work demonstrated a high degree of correlation between changes in DNA methylation, histone modifications and gene expression in the progeny of salt-stressed plants

Antarctic Yeasts as a Source of Enzymes for Biotechnological Applications

Psychrophilic and psychrotrophic yeasts able to live in extremely cold environments like Antarctica produce cold-active enzymes as part of their metabolic adaptation mechanisms. Some of these enzymes could be used for industrial and biotechnological applications requiring high activity at mild/cold temperatures or a fast inactivation by heat. In this chapter, the basic principles for screening of cold-active enzymes and their potential industrial applications (textiles, food and dairy products, brewing and wine industry, laundry, etc) are presented. When it comes to the search of yeasts with cold-enzymes production, Antarctica is one of the most promised environments to work in. Cold-active hydrolytic enzymes from Antarctic yeasts such as lipases, proteases, cellulases and amylases are mentioned in this chapter. Also pectinolytic, lignocellulolytic and oil-related (lipase and esterase) enzymes produced by these microorganisms are presented, focusing on yeasts isolation, enzymes producers screening, and purification and characterization of specific col-active enzymes. The near future should find us discussing the regulation about the use of Antarctic yeast as a source of cold enzymes and, once this point be clarified and approved by the international forums on Antarctic activities regulation, the development and scaling up of these biological products may be addressed.Fil: Martorell, María Martha. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Ruberto, Lucas Adolfo Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Castellanos de Figueroa, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Mac Cormack, Walter Patricio. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin