Blastomyces dermatitidis, coccidiodies immitis and histoplasma capsulatum are the pathogenic fungi that exhibit fungal dimorphism. they are thermally dimorphic fungi that convert from nonpathogenic as filamentous mold with asexual spores(conidia) in soil to pathogenic budding yeast (or spherule in c.immitis) after infectious spores are inhaled into lungs of human.This morphological conversion is required for virulence. conversion to yeast form provide them protection against killing by neutrophils, monocytes and macophages. The conversion from mold to yeast results in a change in cell shape, composition of cell wall,presence of antigenic molecules and expression of viulence traits. Dimorphic fungi other phase specific products that are essential for virulence for eg;In B. dermatitidis only yeast phase expresses immunoreactive protein antigen BAD1, which is responsible for virulence. In H.capsulatum only pathogenic yeast phase expressa released calcium binding protein (CBP1) which is essential for growth in macrophages. laboratory Conditions that are necessary to elicit the coversion and gowth of fungus are temperature, carbon dioxide, cysteine, and estradiol. Binding of estradiol to cell surface receptors accelerates the gowth of coccidioides spherules at 370c. Dimorphism in H.Capsulatum occurs in 3 stages. In first stage, induced by increase in temperature, respiration ceases and level of cytochrome decreases. in second stage conversion from mycelia to yeast occurs for which cysteine and sulfhydryl containing compounds are required. cysteine is required for yeast form to grow. final stage characteized by normal cytochrome level and respiration as yeast grows. B.dermatitidis produces hyphae and one celled conidia at 250c and budding yeast cells at 370c. Solution Blastomyces dermatitidis, coccidiodies immitis and histoplasma capsulatum are the pathogenic fungi that exhibit fungal dimorphism. they are thermally dimorphic fungi that convert from nonpathogenic as filamentous mold with asexual spores(conidia) in soil to pathogenic budding yeast (or spherule in c.immitis) after infectious spores are inhaled into lungs of human.This morphological conversion is required for virulence. conversion to yeast form provide them protection against killing by neutrophils, monocytes and macophages. The conversion from mold to yeast results in a change in cell shape, composition of cell wall,presence of antigenic molecules and expression of viulence traits. Dimorphic fungi other phase specific products that are essential for virulence for eg;In B. dermatitidis only yeast phase expresses immunoreactive protein antigen BAD1, which is responsible for virulence. In H.capsulatum only pathogenic yeast phase expressa released calcium binding protein (CBP1) which is essential for growth in macrophages. laboratory Conditions that are necessary to elicit the coversion and gowth of fungus are temperature, carbon dioxide, cysteine, and estradiol. Binding of estradiol to c.