A’ -Sulfathiazole

A sulfathiazole immunoassay was utilized to determine residues present in raw milk. The LOD was found to be 12 pg kg (based on 80% Bo) however, comparison of the calibration curve from an aqueous solution with a raw milk calibration curve indicated a significant matrix effect. 

Sevag and Ishii (1958) have set about to identify the fluorescent compounds accumulated in a sulfathiazole-inhibited PABA-less mutant of E. coli incubated with PABA. Of three fluorescent compounds isolated, one resembled OF, another was assumed to be a reduced pteroic acid derivative, and the third resembled pteroic acid. Cell extracts incubated with PABA formed a butanol-soluble yellow pigment. On hydrolysis, the pigment yielded PABA, glutamic acid, alanine, and leucine the pigment was inactive for S. faecalis and the E. coli mutant. A yellow pigment absorbing at... 

With FA necessary for purine synthesis, and riboflavin in turn having a purine precursor, Clapper and Meade (1958) reasoned that folic deficiency should induce riboflavin deficiency. The riboflavin content of a S. faecalis strain (derived from a sulfathiazole-resistant folic-requiring Streptococcus mitis) increased as more PGA was supplied, from a low of 3.0 to 50.6 mj[Pg.26]

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