BACTERIAL GROWTH AND NUTRITION
Bacterial Growth Generation Time Time required for a bacterium to give rise to two daughter cells under optimum conditions. • For Escherichia coli and most of the other pathogenic bacteria, -it is 20 minutes; • For Mycobacterium tuberculosis: It is 14 hours • For Mycobacterium leprae: It is 12–13 days Bacterial Count • Total count: […]
Different types of microscopes used in microbiology
Principle: In a dark field microscope, the object appears bright against a dark background. This is made possible by the use of a special darkfield condenser.
Staining Techniques Used in Microbiology
Staining is necessary to produce color contrast and thereby increase the visibility of the object. Before staining, the fixation of the smear to the slide is done:
Gram staining of bacteria (Principle of Gram staining and steps in Grams’ staining procedure)
The structure of the organism’s cell wall determines whether the organism is gram-positive or negative. When stained with a primary stain and fixed by a mordant, some bacteria can retain the primary stain by resisting decolorization while others get decolorized by a decolorizer.
Difference between bacterial endotoxin and exotoxin
Difference between bacterial endotoxin and exotoxin
Bacteria, General morphology, and structural components
Prokaryotic cells almost always are bounded by a fairly rigid and chemically complex structure present between the cell membrane and capsule/slime layer called the cell wall.
The shape of bacteria (Coccus, Bacillus, Spirochete, Actinomycetes)
Depending upon the shape, bacteria are classified into several types.