Which do gram positive bacteria react to, and which do gram negative don react to?
Gram positive bacteria have a larger peptidoglycan layer in their cell wall (50-90% peptidoglycan) Gram negative bacteria have a thin peptidoglyacan layer (10%) in their cell wall. They also have lipopolysaccharides in their outer membrane, an endotoxin which increases the severity of inflammation. “There are four basic steps of the Gram stain, which include applying a primary stain (crystal violet) to a heat-fixed smear of a bacterial culture, followed by the addition of a mordant (Gram’s iodine), rapid decolorization with alcohol or acetone, and counterstaining with safranin or basic fuchsin. Crystal violet (CV) dissociates in aqueous solutions into CV+ and chloride (Cl – ) ions. These ions penetrate through the cell wall and cell membrane of both Gram-positive and Gram-negative cells. The CV+ ion interacts with negatively charged components of bacterial cells and stains the cells purple. Iodine (I – or I3 – ) interacts with CV+ and forms large complexes of crystal violet and iodine
