PubMed Health⌕ Search

Biomedical subjects

J A Fuchs

Publications and source records attributed to J A Fuchs.

At least 91 records · Page 5Linked to original sources
PubMed1983

Characterization of the mRNA coding for ribonucleoside diphosphate reductase in Escherichia coli.

Total Escherichia coli RNA was separated by electrophoresis on methyl mercury agarose gels, transferred to diazobenzyloxymethyl-paper, and hybridized to various DNA probes containing different segments of the nrd genes to determine the organization of these genes. A 3.2-kilobase polycistronic mRNA transcript which hybridizes to both the nrdA and nrdB genes indicated that the nrdA and nrdB genes are organized in an operon. The polycistronic transcript contained the nrdA gene at the 5' end and the nrdB gene at the 3' end. The size of the polycistronic mRNA was sufficient to code for the 80,000-molecular-weight B1 protein and the 40,000-molecular-weight B2 protein. The results also indicated that the nrdA and nrdB genes are the only genes in E. coli that code for ribonucleoside diphosphate reductase. Two smaller RNA species that hybridized to nrd DNA were observed and probably overlap with the 3.2-kilobase nrd mRNA.

Escherichia coli↗
PubMed1978

Role of glutathione in reversing the deleterious effects of a thiol-oxidizing agent in Escherichia coli.

Diamide was found to be much less specific for the oxidation of glutathione in vivo in Escherichia coli than had been previously assumed. In vivo, only a slight alteration of the ratio of reduced to oxidized glutathione was found, whereas a significant amount of glutathione was found in the form of mixed disulfide with proteins. This latter occurrence was postulated as being responsible for the bacteriostatic effect of diamide.

Azo Compounds↗
PubMed1978

Regulation of the synthesis of ribonucleoside diphosphate reductase in Escherichia coli: specific activity of the enzyme in relationship to perturbations of DNA replication.

Ribonucleoside diphosphate reductase (RDP reductase) activity was found to greatly increase after a shift to the nonpermissive temperature in Escherichia coli mutants temperature sensitive for DNA elongation (dnaE dnaG dnaZ lig) or DNA initiation (dnaA dnaC dnaI). However, the kinetics of increase in RDP reductase after a shift to nonpermissive conditions were significantly different in initiation-defective mutants compared with elongation-defective mutants. In strains without defects in DNA metabolism, the specific activity of RDP reductase was found to increase with increasing growth rate. Nutritional shifts to faster growth conditions caused cells to transiently overproduce RDP reductase before adjusting to the new steady-state conditions.

DNA Replication↗
PubMed1977

Regulation of ribonucleoside diphosphate reductase synthesis in Escherichia coli: increased enzyme synthesis as a result of inhibition of deoxyribonucleic acid synthesis.

Inhibition of deoxyribonucleic acid (DNA) synthesis in Escherichia coli by chemical inhibitors or by shifting cultures of temperature-sensitive elongation (dnaE and dnaB) or initiation (dnaA) mutants to nonpermissive conditions led to greatly increased synthesis of the enzyme ribonucleoside diphosphate reductase, which catalyzes the first reaction unique to the pathway leading to DNA replication. In contrast to the Gudas and Pardee proposed model for control of the synthesis of DNA repair enzymes, in which both DNA inhibition and DNA degradation are involved, DNA synthesis inhibition in recA, recB, recC, or lex strains results in increased synthesis of ribonucleotide reductase, which suggests that DNA degradation is not required. We propose that inhibition of DNA synthesis causes a cell to accumulate an unknown compound that stimulates the initiation of a new round of DNA replication, and that this same signal is used to induce ribonucleotide reductase synthesis.

Bacterial Proteins↗
PubMed1976

Mapping of nrdA and nrdB in Escherichia coli K-12.

The structural genes coding for the B1 and B2 subunits of the enzyme ribonucleoside diphosphate reductase, nrdA (formerly designated dnaF) and nrdB, respectively, have been mapped in Escherichia coli. They are located at approximately 48 min. The gene order in this region of the E. coli chromosome was found to be purF glpT nrdB nrdA nalA cdd dcd his.

Chromosome Mapping↗
PubMed1975

Isolation of an Escherichia coli mutant deficient in glutathione synthesis.

A mutant of Escherichia coli that contains essentially no detectable glutathione has been isolated. The mutant contains a very low level of the enzyme glutathione synthetase and accumulates lambda-glutamyl cysteine at a concentration approximately equal to the level of glutathione found in its parent. No significant differences in growth were observed between the mutant and its parent. However, the activity of at least one enzyme was found to be affected by the absence of glutathione; the specific activity of the B1 subunit of ribonucleoside diphosphate reductase was greatly reduced. The possibility that the decreased B1 activity is due to a mutation in the structural gene coding for B1 or its regulatory gene could be eliminated. This suggests that one role of glutathione in the cell is to maintain at least this one protein in an active state. We propose the designation gshB for the gene coding for glutathione synthetase.

Cell-Free System↗
PubMed1971

Deoxycytidine triphosphate deaminase: characterization of an Escherichia coli mutant deficient in the enzyme.

A mutant of Escherichia coli, previously shown to contain abnormal nucleoside triphosphate pools, was found to be defective in its ability to synthesize thymidine nucleotides. The defect is not in the enzyme thymidylate synthetase but in deoxycytidine triphosphate deaminase, an enzyme that supplies deoxyuridine monophosphate, the substrate for thymidylate synthetase.

Aminohydrolases↗
PubMedDate not supplied

The evolving concept of worksetting health promotion.

It is clear that the seeds for worksetting health promotion were planted long ago. Development can be attributed to three historical bases--health education, employee assistance, and health screening programs. This article provides a historical review of these activities and describes the evolution of workplace health promotion programming.

Health Education↗
PubMedDate not supplied

Behavioral risk factors in an Amish community.

A representative sample of 400 Amish adults residing in Holmes County, Ohio, was interviewed about certain health risk characteristics and behaviors, using the Behavioral Risk Factor Survey (BRFS). For purposes of comparison, a representative sample of 773 non-Amish adults responded to the same survey by telephone interviews. In general, the Amish report lower rates of alcohol and tobacco consumption than their non-Amish counterparts. The Amish are less likely to salt their food and are more likely to take vitamin supplements, but do not differ from non-Amish in the consumption of "health foods." Amish men and women are less likely to be trying to lose weight than their non-Amish counterparts. Further, the Amish are less likely to engage in leisure-time physical activity or in exercise associated with attempts to lose weight or deal with hypertension. Amish women are less likely to use seat belts than non-Amish women, whereas men in both groups appear rather similar. Although some differences could be influenced by response biases, many are supported by less systematic observations of Old Order Amish societies. The patterns of health behavior reflect characteristics of Amish culture and may be responsible for certain favorable mortality rates among the Amish population.

Adult↗