医学真菌学（medicalmycology）.PPT

医学真菌学（medical mycology） Comparison of fungi and bacteria Role of fungi in nature There are approximately 70,000 recognized species of fungi. Most are beneficial to humankind. production of food antibiotics and immunosuppressive drugs used as model systems in molecular biology Medical Mycology the subject on pathogenic fungi Some fungi act as the plant and animal pathogens in the agricultural industry. About 300 species of fungi cause human infections. Cellular Morphology A pathogenic fungi can exist either as yeasts（酵母菌） or as mold (霉菌). Yeasts Yeasts are unicellular organisms without hyphae. Yeast propagation The yeasts propagate usually by budding and rarely by binary fission. If the yeast continue to propagate by forming more and more buds, but do not detach from one another, they will produce elongated forms similar to hyphae called pseudohyphae. Molds Molds have two different structural parts: Hyphae and Spores. Hyphae are multi-cellular filamentous structures. Hyphae form branches and the pattern of branching is helpful for morphological identification. according to hyphae do or do not have septa they are called septate or nonseptate hyphae. Asexual spores An aerial hyphae often produces asexual propagules named asexual spores (produced by one cell). Conidium is the most common asexual spore. Relatively large and complex conidia are termed?macroconidia, while the smaller and simpler conidia are termed?microconidia. When many conidia are enclosed in a sac, it is called as endospores / sporangiospore. Asexual spores Sporangiospore(孢子囊孢子):many conidia are enclosed in a sac Asexual spores Conidium （分生孢子） macroconidia , large and complex conidia microconidia the smaller and simpler conidia Asexual spores Thallospore (叶状孢子) Arthrospore (关节) Chlamydospore (厚膜) Blastospore (芽生) Sexual spores Sexual spores are produced by fusion of one male and one female cell. They include ascospore（子囊孢子）, basidiospore（担孢子）, oospore（卵孢子） and zygospore（接合孢子）。 T