As multi-drug resistant bacteria became more prevalent in the 1990s, colistin started to get a second look as an emergency solution, in spite of toxicity.Colistin has also been used in agriculture, particularly in China from the 1980s onwards. Chinese production for agriculture exceeded 2700 tons in 2015. China banned colistin use for livestock growth promotion in 2016. Biosynthesis
The biosynthesis of colistin requires the use of three amino acids: threonine, leucine, and 2,4-diaminobutryic acid. The linear form of colistin is synthesized before cycliziation. Non-ribosomal peptide biosynthesis begins with a loading module and then the addition of each subsequent amino acid. The subsequent amino acids are added with the help of an adenylation domain (A), a peptidyl carrier protein domain (PCP), an epimerization domain (E), and a condensation domain (C). Cyclization is accomplished by a thioesterase. The first step is to have a loading domain, 6-methylheptanoic acid, associate with the A and PCP domains. Now with a C, A, and PCP domain that is associated with 2,4-diaminobutryic acid. This continues with each amino acid until the linear peptide chain is completed. The last module will have a thioesterase to complete the cyclization and form the product colistin. References
Further reading
Reardon S (December 2015). "Spread of antibiotic-resistance gene does not spell bacterial apocalypse — yet". Nature. doi:10.1038/nature.2015.19037. External links
"Colistimethate sodium". Drug Information Portal. U.S. National Library of Medicine. "Colistin sulfate". Drug Information Portal. U.S. National Library of Medicine. "Colistin topics page (bibliography)". Science.gov.
RA is a chronic disease, and although rarely, a spontaneous remission may occur, the natural course is almost invariably one of the persistent symptoms, waxing and waning in intensity, and a progressive deterioration of joint structures leading to deformations and disability.There is an association between periodontitis and rheumatoid arthritis (RA), hypothesised to lead to enhanced generation of RA-related autoantibodies. Oral bacteria that invade the blood may also contribute to chronic inflammatory responses and generation of autoantibodies. History
The first recognized description of RA in modern medicine was in 1800 by the French physician Dr Augustin Jacob Landré-Beauvais (1772–1840) who was based in the famed Salpêtrière Hospital in Paris. The name "rheumatoid arthritis" itself was coined in 1859 by British rheumatologist Dr Alfred Baring Garrod.The art of Peter Paul Rubens may possibly depict the effects of RA. In his later paintings, his rendered hands show, in the opinion of some physicians, increasing deformity consistent with the symptoms of the disease. RA appears to some to have been depicted in 16th-century paintings. However, it is generally recognized in art historical circles that the painting of hands in the 16th and 17th century followed certain stylized conventions, most clearly seen in the Mannerist movement. It was conventional, for instance, to show the upheld right hand of Christ in what now appears a deformed posture.