AIMS To develop a sensitive, direct, automated method for the measurement of serum and red cell thiamin. METHODS A microbiological assay using a chloramphenicol resistant strain of Lactobacillus fermenti as the test organism was developed. Addition of chloramphenicol and cycloheximide to the assay medium suppressed bacterial and yeast contamination and enabled tests to be automated without re...

Vitamin B(1) in its active form thiamin pyrophosphate is an essential coenzyme that is synthesized by coupling of pyrimidine (hydroxymethylpyrimidine; HMP) and thiazole (hydroxyethylthiazole) moieties in bacteria. Using comparative analysis of genes, operons, and regulatory elements, we describe the thiamin biosynthetic pathway in available bacterial genomes. The previously detected thiamin-reg...

The observation that thiamin (B1) or pyridoxine (B.) serves as an alternate growth stimulant for one strain of brewers' top yeast and the conditions under which this equivalence occurs have been discussed elsewhere (Moses and Joslyn, 1953). The ability of the organism to synthesize thiamin or pyridoxine when grown in media deficient in either and its ability to form carboxylase under these cond...

A genetic screen was developed for the identification of genes related to thiamin biosynthesis and degradation. Genes conferring resistance to bacimethrin or 4-amino-2-trifluoromethyl-5-hydroxymethylpyrimidine were selected from Escherichia coli and Bacillus subtilis genomic libraries. Hits from the selection included the known thiamin biosynthetic genes thiC, thiE, and dxs as well as five gene...

the results of researches in the field of the using x-ray in all over the world have been successful. the main subject which needs more investigation and have been allocated part of the researches in most of the atomic research institutes, is the research about possible harms of irradiated food for human beings, base on the researches, using irradiation for inhibition of sprouting and preservat...

Vitamin B1 in its active form thiamin pyrophosphate is an essential coenzyme that is synthesized by coupling of pyrimidine (hydroxymethylpyrimidine; HMP) and thiazole (hydroxyethylthiazole) moieties in bacteria. Using comparative analysis of genes, operons, and regulatory elements, we describe the thiamin biosynthetic pathway in available bacterial genomes. The previously detected thiamin-regul...

We have examined the activity of the thiamin phosphate pyrophosphorylase in Arabidopsis thaliana wild type and in a mutant (th-1) which requires exogenous thiamin for growth. Mutant and wild-type plants grown in 1 x 10(-7) molar thiamin were used for the examination of the production of thiamin and thiamin monophosphate (TMP) using 4-methyl-5-hydroxyethylthiazole phosphate and 2-methyl-4-amino-...

SEVEN VITAMINS HAVE TO DATE PROVED ESSENTIAL FOR THE SURVIVAL AND MULTIPLICATION OF A MOUSE FIBROBLAST (STRAIN L) AND A HUMAN CARCINOMA CELL (STRAIN HELA) IN TISSUE CULTURE: choline, folic acid, nicotinamide, pantothenic acid, pyridoxal, riboflavin, and thiamin. It was necessary to cultivate the cells for 5 to 15 days in a medium lacking the specific vitamin before the deficiency became apparen...

A point mutation in the thi1 gene, involved in the synthesis of thiamin, has been identified in a tz-201 mutant line of Arabidopsis thaliana. The mutation occurs in a conserved protein domain and prevents the mutant plants from synthesizing thiamin. Complementation assays in yeast thi4 mutant confirm that this mutation hinders thiamin synthesis and, thus, is responsible for the tz phenotype. No...