Experiment 4 Effects of physical chemical and biological

Experiment 4 Effects of physical, chemical and biological agents on bacteria

Outline Moist heat Bacteria Culture media Equipments E. coli B. subtitis Broth Water bath UV S. aureus E. coli Agar plates UV light Reagents Non Chemical &biological agents Non 2% iodine 1% crystal violet 2% mercurochrome garlic paper disks of penicillin paper disks of streptomycin

§ Effect of moist heat Bacteria 4 students / group E. coil (liquid) (shake it) Temperature 100℃ B. subtitis (slant) RT 100℃ RT Time 5 min 30 min Control Tube number 1# 2# 3# 4# 5# 6# Stand A Stand B Stand C

§ Effect of UV light Condition： expose UV light for 30 min Bacterial strain： S. aureus Inoculation method：Streak plate (with cotton stick) mark UV UV 30 min

§ Effect of chemical and biological agents Reagents: 1. 1% crystal violet 2. 2% mercurochrome 3. 2% iodine 4. garlic 5. paper disk of penicillin Bring with me tomorrow ！ 6. paper disk of streptomycin Species： S. aureus E. coli 1 agar plate Mark 1 Manipulation 6 2 5 3 4

Observation of results § Part 1. Effect of moist heat on bacteria; E. coli, B. subtitis § Part 2. Effect of UV light on bacteria; S. aureus § Part 3. Effect of chemical & biological agents on bacteria; E. coli, S. aureus

Moist heat § E. coli 1#: 100℃, 5 min 2#: 100℃, 30 min 3#: RT, Control § B. subtitis 4#: 100℃, 5 min 5#: 100℃, 30 min 6#: RT, Control

Effect of moist heat on bacteria Record: Strains 100℃, 5 min 100℃, 30 min Control E. coli B. subtitis Clear: “-” or bacterial growth: “+” Surface growing / Turbidity / Precipitate growing;

UV radiation Describe result: § Covered part § Radiated part UV

Effect of chemical and biological agents § Measure inhibition zone • diameter or 2 radius

Effect of chemical and biological agents Inhibition zone diameter (mm) >15 mm 10~15 mm <10 mm susceptibility degree Extremely sensitive Medium sensitive Slight sensitive 0 mm Resistant Record: Diameter of Inhibition Zone (mm) Cultures E. coli S. aureus Susceptibility degree 1% Crystal violet 2% Penicillin Streptomycin 2%Iodine Mercurochrome Garlic