Peroxisome proliferator-activated receptors (PPARs) and related transcription factors in differentiating astrocyte cultures

Peroxisome proliferator-activated receptors (PPARs), retinoid X receptors (RXRs), CCAAT/enhancer binding proteins (C/EBPs) and -catenin are transcription factors involved in cell differentiation. The aim of this work was to investigate the occurrence and variations of these proteins during astrocyte differentiation. Primary cultures of mouse cortical astrocytes were characterized using nestin, A2B5 and glial fibrillary acidic protein (GFAP) as differentiation markers, during a period of 21 days in vitro (DIV). Glycogen and triglyceride accumulation were also studied. At 3 DIV the cultures were mainly constituted by neural progenitor cells, as assessed by their immunofluorescent pattern. At this time PPARs and -catenin were localized to the cytoplasm. Interestingly, some cells contained Oil Red O-positive lipid droplets. Between 7 and 21 DIV, nestin decreased, while GFAP increased, indicating ongoing astroglial differentiation. -catenin, predominantly nuclear at 7 DIV, later localized to membranes. Redistribution of all three PPAR isotypes from the cytoplasm to the nucleus was observed starting from 7 DIV. Between 7 and 14 DIV, C/EBP, PPAR, RXR and glycogen content increased. Between 14 and 21 DIV, PPAR/ decreased, while PPAR, C/EBP and and lipid droplet-containing cells increased. At 21 DIV both A2B5/GFAP and A2B5/GFAP cells were predominantly observed, indicating differentiation toward type-1 and type-2 astrocytes, although the presence of GFAP cells demonstrates the persistence of neural precursors in the culture even at this time point. In conclusion, our results, reporting modifications of PPARs, RXRs, C/EBPs and -catenin during culture time, strongly suggest the involvement of these transcription factors in astrocyte differentiation. Specifically, -catenin translocation from the nucleus to plasma membrane, together with PPAR/ decrease and C/EBP increase, could be related to decreased proliferation at confluence, while PPAR and and all C/EBPs could participate in differentiation processes, such as glycogenesis and lipidogenesis

Truffles and Morels: Two Different Evolutionary Strategies of Fungal-Plant Interactions in the Pezizales

Pezizales are a widespread group of fungi, basal to the other filamentous ascomycetes. Most species live in soil as saprobes, in a mycorrhizal relationship with a wide range of plants, or as plant parasites. The lineage Morchellaceae–Discinaceae–Helvellaceae–Tuberaceae includes most of the commercially valuable species in the order. The truffles in the genus Tuber and morels in the genus Morchella arguably command more interest in culinary circles than any other groups of mushrooms. In recent years, the interactions of these fungi with plants have been thoroughly researched although many aspects still need to be clarified. In this chapter, we describe and compare these two groups of mushrooms and take a look at the evidence as to whether there are real trophic differences from those traditionally held and if things are not quite as simple as our forebears would have had us believe. We explore the range of host plants involved in the interactions, the morpho-anatomy of symbiotic structures, the molecular mechanisms of symbiosis, and the influence of other microbial species