Effect of Aflatoxin B1 on the Deoxyribonucleic Acid Polymerase of Escherichia coli.

Abstract

1052AFLATOXIN EFFECT ON DNA POLYMERASE against insulin as a source folr this biologic effect. In this respect the activity closely resembles the "atypical" serum insulin described by Samaan et aZ(9,lO); however, the present characterization of UILA from an obese human subject suggests that it is more closely related to albumin than to unmodified insulin.Summary. The insulin-like activity found in urine protein from obese subjects during fasting was characterized by benmic acid precipitate and Sephadex column chromatography. The major portion of the urine insulin-like activity was found in a single protein peak which was homogeneous by polyacrylamlide gel electrophoresis, and its electrophoretic mobility was identical to human serum albumin. This active fraction was significantly neutralized by rabbit antiserum to human serum albumin. These results suggest that the insulin-like activity in urine of obese subjects is more closely associated with albumin than with unmodified insulin.

The isolation of a fungal metabolite which exhibits antimicrobial synergy with sterigmatocystin

“…Garner et al (1972) reported that liver microsomal enzymes were able to convert STG to a metabolite which inhibited the growth of Salmonella typhimurium TA1530. Although similar observations have been made concerning aflatoxin B1 and aflatoxin G1 (Garner et al 1971;, these two mycotoxins also exhibit broad antibiotic spectra without metabolic activation (Burmeister & Hesseltine 1966;Wragg et al 1967;Lillehoj & Ciegler 1967;Lillehoj et 01. 1967).…”

Aflatoxin B1–Formamidopyrimidine DNA Adducts: Relationships between Structures, Free Energies, and Melting Temperatures

“…Although ssDNA shows a slight preference for a , re-association of the complementary DNA strands strongly favors b [39,53,54], which is a consequence of (1) a to b conversion in ssDNA being very slow, (2) ssDNA life-time being too brief, and (3) b being more conducive than a to the re-association [39]. a and b are strong blockers of DNA replication [13,50,53,55,56,57,58,59,60,61,62,63,64,65] and transcription [23,25,32,55,59,60,61,62,66,67,68,69]. Additionally, b is a strong mutagen for it is the material cause of the b ·C→T·A transversion substitution mutation [46,49,53,64,70,71,72,73,74,75,76,77,78,79,80,81,82], the efficient cause of which is an erroneous bypass of b lesion by the translesion DNA polymerase ζ [64,65].…”

Biochemical Alternations in Bacillus megaterium as Produced by Aflatoxin B11

“…The toxin inhibited deoxyribonucleic acid (DNA) synthesis and, to a lesser extent, ribonucleic acid (RNA) and protein synthesis. Binding capacity studies indicated that aflatoxin has an affinity for bacterial DNA (4, 6) and inhibits DNA polymerase activity (11). There are no reports on the chemical analyses of the aberrant forms of cell walls of Bacillus megaterium NRRL B-1368, previously demonstrated to be aflatoxin sensitive (1), produced in the presence of aflatoxin.…”