Gram Stain Differential stain (Hans Christian Gram, a Danish doctor ). He developed a new method to...
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Transcript of Gram Stain Differential stain (Hans Christian Gram, a Danish doctor ). He developed a new method to...
Gram Stain Differential stain (Hans Christian Gram, a Danish
doctor ).He developed a new method to stain bacteria so they can
bevisible in specimen samples. Differentiate bacteria into two
large groups (the GramPositive and the Gram negative). Gram status
is important in medicine; the presence orabsence of a cell wall
will change the bacterium'ssusceptibility to some antibiotics.
Almost all bacteria are described by their Gram stain
characteristics.
Based on differences of Cell wall structures Classifies bacteria
into 2 large groups: Gram-positive and Gram-negative. Gram-positive
bacteria have a thick mesh-like cell wall made of 50% to 90%
peptidoglycan, while Gram-negative bacteria only have around 10% of
their cell wall made up of peptidoglycan. Gram Positive &
Negative Bacteria Reagents for Gram Stain
Crystal Violet (purple). Primary stain; positive stain Stains cell
wall purple Iodine Mordant Combines with primary stainto form an
insoluble complexthat gets trapped inbacterialcell wall Staining
the slide: Start with a heat-fixed slide of your material. Recall,
Gram positive bacteria have a single cell membrane and hardy outer
cell wall made of peptidoglycan. In contrast. Gram negative cells
have two membranes. In between the two membranes is the
*periplasmic space* which contains a layer of peptidoglycan.