observation of bacteria using staining procedures simple staining gram staining
TRANSCRIPT
Observation of bacteria using staining procedures
Simple staining
Gram staining
Simple Staining
• Smear preparation:– A drop of water is placed in the centre of a slide– One loopfuls of organisms is transferred to the centre of
slide– Spread the organisms over the slide– The smear is allowed to dry– Slide is passed through flame several times to heat-kill and
fix organisms• A bacterial stain is stained with crystal violet (fuchsin,
methylene blue) 1 min• Stain is briefly washed off slide with water Allow the slide to
air-dry and examine with an oil immersion objective
Bacillus subtilis
Gram Staining1884 Christian GramStaining technique that separates bacteria into two groups:Gram-positive bacteriaGram-negative bacteria
Based on the ability to retain crystal violet during decolorization with alcohol
Gram-positive cell wall
Gram-negative cell wall
1.Step. Fixation, staining with crystal violet
2. Step. Gram`s iodine
3. Step. Ethyl alcohol 4. Step. Counterstaining with fuchsin
G+ violet (blue)
G- red (pink)
Grampositive bacteria
• Steptococcus • Staphylococcus• Lactobacillus• Bacillus • Clostridium
Gram-negative bacteria
• Escherichia
• Salmonella
• Vibrio
• Treponema
Gram Staining
• Smear preparation.• Stain with crystal violet 1 min.• Add Lugol solution 1 min.• Decolorize with alcohol 10-15 seconds.• Wash with water.• Stain with fuchsin 2 min• Allow the slide to air-dry• Examine with an oil immersion objective