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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 S.aureus E.coli Agar plates 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 5min 30min Control 5min 30min Control Tube number 1# 2# 3# 4# 5# 6# Stand A Stand A Stand B Stand B Stand C Stand C Effect of UV light Condition: expose UV light for 30min Bacterial strain: S.aureus Inoculation method:Streak plate (with cotton stick) mark UV UV 30min 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 1 agar plate Mark Manipulation 1 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℃, 5min 2#: 100℃, 30min 3#: RT, Control B.subtitis 4#: 100℃, 5min 5#: 100℃, 30min 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) >15mm 10~15mm <10mm susceptibility degree Extremely sensitive Medium sensitive Slight sensitive 0mm Resistant Record: Diameter of Inhibition Zone (mm) Cultures E.coli S.aureus Susceptibility degree 1% Crystal violet 2% Penicillin Streptomycin 2%Iodine Mercurochrome Garlic