Gramicidin is a heterogeneous mixture of six antibiotic compounds, Gramicidins A, B and C, making up 80%, 6%, and 14% respectively, all of which are obtained from the soil bacterial species
Bacillus brevis and called collectively Gramicidin D. Gramicidin D are linear pentadecapeptides; that is, they are long protein chains made up of 15 amino acids. This is in contrast to
Gramicidin S which is a cyclic peptide chain. Gramicidin is active against
Gram-positive bacteria, except for the Gram-positive
bacilli, and against select
Gram-negative organisms, such as
Neisseria bacteria. Its therapeutic use is limited to topical application as it induces
hemolysis in lower concentrations than bacteria cell death thus cannot be administered internally. The exterior
epidermis is composed of dead cells, thus applying it to the surface of the skin will not cause harm. It is used primarily as a topical antibiotic and is one of the three constituents of consumer antibiotic
Neosporin Ophthalmic Solution. In 1939 the American microbiologist
René Dubos isolated the substance tyrothricin and later showed that it was composed of two substances, gramicidin (20%) and
tyrocidine (80%). These were the first antibiotics to be manufactured commercially.
See more at Wikipedia.org...
Free Download Now!
