1. Objectives Use appropriate microbiology media, test systems, and lab equipment. Describe the general properties and characteristics of bacteria – By doing this, students will be able to observe growth characteristics of bacteria

2. Microbes in the Environment

3. Ubiquity of Microorganisms This means that microorganisms can be found everywhere – Soil, water, plants, animals Many microbes are free-living – They don’t live on a specific host – Most are nonpathogenic (non-disease causing) Today we will culture microbes from the environment

4. Ubiquity of Microorganisms Simple streak pattern

5. Culturing Microbes Microbes need certain nutrients and growth factors to grow and reproduce – Carbon – Nitrogen – Sulfur – Phosphorus – Trace elements – Organic growth factors

6. Culture Media Culture medium: Nutrients prepared for microbial growth Sterile: No living microbes – Autoclave at 121°C for 15 min at 15 psi – Steam under pressure Inoculum: Introduction of microbes into medium Culture: Microbes growing in/on culture medium

7. Culture Media A. Chemically defined media: Exact chemical composition is known B. Complex media: Extracts and digests of yeasts, meat, or plants – Chemical composition varies slightly from batch to batch – Nutrient broth

10. Agar Complex polysaccharide derived from seaweed Used as solidifying agent for culture media in Petri plates, slants, and deeps Generally not metabolized by microbes Liquefies at 100°C Solidifies at ~40°C – Once solid, it will remain until heated again to 100°C

11. Labeling/Incubating Plates Initials Date Sample

12. Labeling/Incubating Plates Labeling Plate On back of plate with sharpie Initials Date Sample Incubation Plate 37⁰C Upside-down 24-48 hrs

13. What to Expect Bacterial make colonies – Thousands same cells – All cells in colony originate from single parent Variety of shapes, sizes, and color of various colonies