菌落形态学Bacterial Colony Morphology

Purpose Identifying and categorizing different, isolated bacterial colonies based upon varied appearance and morphology (form. and structure) will permit the selection and transfer of different species from a mixed culture, and allow transfer of a single colony to a sterile medium for cultivation of a pure culture. This exercise also shows how many diverse bacteria and fungi are present in our environment, as exhibited by the varied morphologies.

Principles When a single bacterial cells is deposited on the surface of a nutritive medium, it begins to divide exponentially. After thousands (up to billions) of cells are formed, a visable mass appears. This mass of cells is called a colony. Each species of bacterial or fungal organism will exhibit characteristic colonies.

Additional Information Colony charachterisitcs are described in standard terminology to permit interpretation by other persons. These terms may appear to be complicated; however, you will soon become familiar with them. Remember: the best descriptions are complete, but concise.

Terms
1. Colony shape and size: round, irregular, punctiform. (tiny)
2. Margin (edge): entire (smooth), undulate (wavy), lobate (lobed)
3. Elevation: convex, umbonate, flat, raised
4. Color: color or pigment, plus opaque, translucent, shiny or dull
5. Texture: moist, mucoid, dry (or rough).

Use the images below to practice describing different colony morphologies.