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 Read More …
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 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:
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
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.
Depending upon the shape, bacteria are classified into several types.