Consequently, stem cell therapy might provide a means to reduce radiation-induced side BU 4061T effects. Local injection of stem cells could bring multipotent functional cells, able to replace the differentiated cells, interact with the environment through secretion of biofactors, and regulate the inflammatory microenvironment, while inducing and participating in neoangiogenesis. The human pathogen Paracoccidioides brasiliensis, a dimorphic fungus, is the causative agent of paracoccidioidomycosis, the most prevalent systemic mycosis in Latin America. The yeast phase is the infectious form and grows at 37uC. The lungs are the primary site of infection, but the yeasts can spread to other organs and cause systemic disease. The yeast cells of P. brasiliensis have characteristic features of cell division and budding that allow them to be identified unequivocally by microscopy. One such feature is the co-existence of mother and bud cells during yeast growth, resulting in a wide variety of sizes and shapes and indicating that these cells have an intricate mechanism for regulating polarity during their growth. P. brasiliensis does not seem to grow as a single clone with a constant phenotype, and this plasticity may promote the appearance of mutants that are able to evade the host immune response. The cell wall of P. brasiliensis, like those of many other fungi, is a network of glycoproteins and polysaccharides that protects the fungal cell from environmental stress. Many of the glycoproteins contain N-glycans attached to an asparagine residue within the sequence N-X-S/T, where X denotes any amino acid except proline. N-linked glycans are involved in glycoprotein folding, intracellular transport, and protection from proteolytic degradation. The N-glycans of Candida albicans proteins, for example, have recently been shown to be essential for the integrity of the cell wall as well as for fungus-host interactions. N-glycosylation can be altered by a number of natural products, chief of which is tunicamycin. TM belongs to the nucleoside class of antibiotics and inhibits N-glycosylation by blocking the transfer of N-acetylglucosamine-1-phosphate from UDPGlcNAc to dolichol-P, thereby decreasing the formation of dolichol-PP-GlcNAc. TM has been used extensively to study the roles of N-glycans in glycoprotein maturation, secretion, and function, and its use has been cited in thousands of papers since its discovery in 1973. Chitin, the second most abundant polysaccharide in nature, is among the best-studied examples of fungal cell wall polysaccharides. It consists of an unbranched homopolymer of 1,4-b-linked N-acetylD-glucosamine and is present in the cell walls of all fungi studied to date. Its position at specific sites throughout the cell cycle allows it to maintain the overall strength of the wall. In P. brasiliensis, chitin is one of the major components of the cell wall and is involved in the morphogenesis and integrity of the wall. The chitinolytic enzyme machinery of fungi consists of chitinases and Nacetyl-b-D-glucosaminidase. The functions of chitin-degrading enzymes in fungi include both the use of exogenous chitin as a nutrient source and cell wall remodeling during the fungal life cycle. NAGase cleaves diacetylchitobiose and higher chitin polymers, including chitotriose and chitotetraose, into GlcNAc monomers.