INTRODUCTION TO BACTERIA (MORPHOLOGY AND STAINING; BIOCHEMICAL CHARACTERISTIC)

INTRODUCTION

Bacteria are one group of microorganisms classified as prokaryotes. They have cell walls that consist of peptidoglycan layers. Bacteria are smaller than fungal spores and can only be seen clearly using the highest magnification of a light microscope. The classification of bacteria depends on the shape, composition of the cell wall, and mobility. According to shape, bacteria can be divided into 3 main types which are coccus, bacillus, and spiral. However, most plant pathogenic bacteria are rod-shaped except Streptomyces (filamentous). 

Gram stain divides bacteria into 2 groups according to the composition of the cell wall such as Gram-positive (with peptidoglycan layer) and Gram-negative (with peptidoglycan and an additional outer membrane). Bacteria that have flagella are mobile.

ACTIVITY 1: MORPHOLOGY OBSERVATION

1.1 : Material

• Specimen Bacillus, E-coli, Pseudomonas

1.2 : Method

1. A colony of bacteria in NA was observed through naked eyes

2. The shape, surface, and edge was recorded

1.3 : Result

Bacteria	Morphology description
Pseudomonas	Shape of colony  - Irregular Surface of colony - Raised Edge of colony - Flat Colour - Dark yellow
Bacillus	Shape of colony  - Round Surface of colony - Flat Edge of colony - Lobate Colour - Cream
E-coli	Shape of colony  - Irregular Surface of colony - Umbonate Edge of colony - Flat Colour - Light yellow

ACTIVITY 2: GRAM STAINING

2.1 : Material

• Specimen Bacillus, E-coli, Pseudomonas

• Slide

• Dopper

• Water

• Lamp

• Inoculation loop

• Crystal violet

• Iodine

• Alcohol

• Safranin

• Microscope

2.2 : Method

1. A drop of sterile water was dropped on the slide

2. A bacteria was smeared on the slide using a sterile inoculation loop

3. The slide was heated to make sure the slide is dry

4. The slide was put on the rack 

5. 1 to 2 drop of crystal violet was dropped on the slide and the slide was rinsed after 2 minutes

6. 1 to 2 drop of iodine was dropped and was rinsed again using water after 2 minute

7. The alcohol was dropped and allowed to flow out of the slide. This process is continued until the blue color no longer comes out of the slide and the slide was rinsed

8. 1 to 2 drops of safranin was dropped and was rinsed after for 30 second

9. The slide was dried and observed under a microscope

2.3 : Result

Bacteria	Pseudomonas sp.	Bacillus sp.	E-coli
Result	The pink color indicates that Pseudomonas sp. is the negative gram staining	The purple color indicates that Bacillus sp. is the positive gram staining	The pink color indicates that E-coli is the negative gram staining

ACTIVITY 3: CARBOHYDRATE CONSUMPTION 

This test is to determine the ability of the bacteria to break down carbohydrates to produce simple carbon materials as well as energy production.

	Glucose	Sucrose
Pseudomonas sp.
Bacillus sp.
E-coli
Control

ACTIVITY 4: CATALASE TEST 

4.1 : Material

• Specimen Bacillus, E-coli, Pseudomonas

• Slide

• Inoculation loop

• Hydrogen peroxide (3%)

• Dropper

4.2 : Method

1. The specimen was smeared on the slide

2. Two to three drops of hydrogen peroxide are dropped on the slide

3. The observation of the reaction was recorded

4.3 : Result

Bacteria	Pseudomonas	Bacillus	E-coli
Result of test	No air bubble (occur after 10 minutes)	Air bubble occur	No air bubble (occur after 10 minutes)

ACTIVITY 5: SULFIDE HYDROGEN PRODUCTION TEST

Bacteria	Pseudomonas	Bacillus	E-coli
Result of test

ACTIVITY 6: SENSITIVITY TO ANTIBIOTIC 

Bacteria	Pseudomonas	Bacillus	E-coli
Result of sensitivity of antibiotic	Pseudomonas is more sensitive to kanamycin and followed by colistin.  There is no reaction to erythromycin and penicillin	Bacillus is more sensitive to penicillin and followed by kanamycin and colistin respectively. However not sensitive to erythromycin	E-coli is more sensitive to kanamycin and followed by erythromycin and colistin respectively. However not sensitive to penicillin