Define about the Yeast - Saccharomyces?

Classification

Kingdom - Mycetae

Division - Amastigomycota

Class - Ascomycetes

Order - Endomycetales

Family - Saccharomycetaceae

Genus - Saccharomyces

Yeasts are unicellular organisms, which are usually spherical or oval in shape as can be seen in Figure above. Some yeasts may be cylindrical. Few common examples of yeast are Torula, Saccharomyces etc. It is present on cheese and other foods. Colonies are white, pink, moist with unbroken even edges. Cells are oval, colourless. Yeasts are facultative anaerobes and can survive well in various environments. Yeasts reproduce asexually by budding (budding yeast, e.g. Saccharomyces) or by binary fission (fission yeasts - Schizosaccharomyces).

In budding, a small outgrowth called a bud arises. Parent nucleus divides and one nucleus migrates into a bud. Cell wall material is then laid down and the bud breaks away and grows to form a daughter cell. Fission yeast divides into two new cells by elongations followed by division into two. Sexual reproduction is also observed in some yeasts. Ascospores are produced within the ascus through sexual reproduction, which are released and begin the cycle again. As discussed earlier yeasts are both beneficial and harmful. Some yeasts causes disease in human e.g. Candida albican causes urinary and vaginal infections (moniliasis) and mouth infection (thrush).