COLONY MORPHOLOGY DESCRIBING BACTERIAL COLONIES Roba Attar Dr

COLONY MORPHOLOGY: DESCRIBING BACTERIAL COLONIES Roba Attar Dr. Nisreen Tashkandi ROBA ATTAR

AIM of study When cells are grown on nutrient media, a bacterial colonies or groups will appeared. These colonies differ than each other in shape, edge, color, consistency…. . etc These characteristics are important in studying the bacterial cell to identify it and to isolate it in a pure picture. It will be useful to learn the terminology used for describing common colony types. ROBA ATTAR

FORM • The form refers to the shape of the colony. • These forms represent the most common colony shapes you are likely to encounter. ROBA ATTAR IRREGULAR RHIZOID CIRCULAR FILAMENTOUS

SIZE The size of the colony can be a useful characteristic for identification. The diameter of a representative colony may be measured. Tiny colonies are referred to as punctiform. ROBA ATTAR

SURFACE Bacterial colonies are frequently shiny and smooth in appearance. Other surface descriptions might be: veined, rough, dull (not shiny when observed from an angle), wrinkled (or shriveled), glistening (shiny when observed from an angle). ROBA ATTAR

TEXTURE Several terms that may be appropriate for describing the texture or consistency of bacterial growth are: watery, mucoid, brittle (dry and fragile), viscous (growth follow the loop), butyrous (buttery), tough ROBA ATTAR

COLOR It is important to describe the color or pigment of the colony. Also include descriptive terms for any other relevant optical characteristics such as: opaque (not allowing light through), cloudy, translucent (allowing some light through), iridescent. ROBA ATTAR

ELEVATION • This describes the “side view” of a colony. These are the most common. ROBA ATTAR

MARGIN The margin or edge of a colony (or any growth) may be an important characterisic in identifying an organisms. ROBA ATTAR

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Serratia marcescens growing on an agar surface. These colonies are circular, entire, convex, small, shiny, red and opaque. ROBA ATTAR

Small Colonies Pigment Round, Entire Opaque Filamentous Irregular Opaque ROBA ATTAR Large Red Opaque Round, Entire Buff Pigment Irregular, Undulate Opaque

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