Biomaterial Database

Biochemical studies of pyrithiamine-resistant mutants of Escherichia coli K12. 1976

T Kawasaki, and H Sanemori, and Y Egi, and S Yoshida, and K Yamada

The biochemical properties of strains (PT-R101 and PT-R108) of Escherichia coli K12 resistant to growth inhibition by pyrithiamine, and antimetabolite of thiamine, have been studied. Intracellular thiamine pyrophosphate concentration in these resistant strains was slightly but definitely higher than that in the parent strain. Thiamine synthesis from the pyrimidine and thiazole moieties of thiamine by cell suspensions was greater in the resistant strains than the parent strain. The activities of enzymes involved in thiamine biosynthesis in these pyrithiamine-resistant strains were 2-3 times higher than the parent strain (3301), except for thiamine-phosphate kinase, which was indetectable in in vitro assay of the activity. However, other evidence indicates that this enzyme is not defective but is functioning in vivo and, furthermore, that the negligible activity of this enzyme did not affect the growth rate of the mutants. The activities of these enzymes were further enhanced when PT-R101 was grown on 5mM adenine and were reduced almost to zero when the strain was grown on 0.1 muM thiamine in the same way as the parent strain. However, when these resistant strains were grown on a low concentration of thiamine such as 0,05 muM, thiamine synthesis by cell suspensions also decreased, but only to a limited extent compared with the parent strain. These results suggest that PT-R101 and PT-R108 are altered in the mechanisms of regulation of thiamine biosynthesis. Their altered properties might be due to a reduced binding affinity of the repressor protein, which is involved on the regulation of thiamine synthesis, for the corepressor, thiamine pyrophosphate,

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D011726	Pyridinium Compounds	Derivatives of PYRIDINE containing a cation C5H5NH or radical C5H6N.	Compounds, Pyridinium
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000225	Adenine	A purine base and a fundamental unit of ADENINE NUCLEOTIDES.	Vitamin B 4,4, Vitamin B,B 4, Vitamin
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D013831	Thiamine	3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.	Aneurin,Vitamin B 1,Thiamin,Thiamine Mononitrate,Vitamin B1,Mononitrate, Thiamine
D013835	Thiamine Pyrophosphate	The coenzyme form of Vitamin B1 present in many animal tissues. It is a required intermediate in the PYRUVATE DEHYDROGENASE COMPLEX and the KETOGLUTARATE DEHYDROGENASE COMPLEX.	Cocarboxylase,Thiamine Diphosphate,Berolase,Pyrophosphate, Thiamine