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Background Joint forces operate across the range of military operations, in environments of cooperation, competition, and conflict. These forces require access to current and historical operations and intelligence information to [...]

The 1959 film It Happened to Jane was filmed in and around Chester, Connecticut [March/April, p. 62]. In the cast was an actor named Max Showalter, a.k.a. Casey Adams. Evidently [...]

The effects of nalidixic acid in vitro on deoxyribonucleic acid (DNA)- polymerase (deoxyribonucleosidetriphosphate: DNA deoxynucleotidyltransferase, EC 2.7.7.7), deoxyribonucleotide kinases (ATP: deoxymono- and diphosphate phosphotransferases), and deoxyribosyl transferase (nucleoside: purine deoxyribosyltransferase, EC 2.4.2.6) were examined employing partially purified and crude extracts of Escherichia coliATCC 11229 and E. coli15TAU. Nalidixic acid had no inhibitory effect on the DNA-polymerase of the wild-type strain E. coliATCC 11229 at concentrations of 1.4 × 10−3to 2.8 × 10−3m. No inhibition of deoxyribonucleotide kinase activity was observed at concentrations of nalidixic acid ranging from 2 × 10−3to 8.6 × 10−3m. Nalidixic acid (0.43 × 10−4to 0.43 × 10−3m) had no inhibitory effect on the deoxyribosyl transferase activity of crude extracts obtained from E. coliATCC 11229 or E. coli15TAU. Analytical CsCl density gradient centrifugation demonstrated that the DNA obtained after treatment of E. coli15TAU with nalidixic acid was not cross-linked. These results suggest that the prevention of DNA synthesis in vivo by nalidixic acid is not attributable to inhibition of DNA polymerase, deoxyribonucleotide kinase, deoxyribosyl transferase, or to cross-linking of the DNA of treated cells.

Cook, Thomas M., (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William A. Goss, and William H. Deitz. Mechanism of action of nalidixic acid on Escherichia coli. V. Possible mutagenic effect. J. Bacteriol. 91:780–783. 1966.—With a streptomycin-dependent organism, Escherichia coliATCC 11143, it has been shown that exposure to nalidixic acid, under conditions permitting some bactericidal action, results in an increased number of streptomycin-independent bacteria among the survivors. This effect is evident only with proliferating cultures, and is related to the concentration of nalidixic acid and the duration of exposure.

Cook, Thomas M.(Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Deitz, and William A. Goss. Mechanism of action of nalidixic acid on Escherichia coli. IV. Effects on the stability of cellular constituents. J. Bacteriol. 91:774–779. 1996.—Treatment of Escherichia coli15TAU with nalidixic acid resulted in degradation of the nucleic acids of the cells, whereas protein was unaffected. Deoxyribonucleic acid (DNA) degradation appeared to be more extensive than ribonucleic acid degradation during periods of comparable bactericidal action. The onset of DNA degradation was evident prior to a measurable bactericidal effect. However, within the range of 2 to 20%, DNA degradation was accompanied by a decrease in viable cell numbers. Degradation of DNA to acid-soluble material occurred only under conditions permitting the bactericidal action of nalidixic acid. Arrest of the bactericidal action of nalidixic acid by the addition of dinitrophenol or chloramphenicol also inhibited DNA degradation. The acid-soluble products, which were excreted into the medium, have not been characterized completely, but probably were not phosphorylated.

Deitz, William H.(Sterling-Winthrop Research Institute, Rensselaer, N.Y.), Thomas M. Cook, and William A. Goss. Mechanism of action of nalidixic acid on Escherichia coli. III. Conditions required for lethality. J. Bacteriol. 91:768–773. 1966.—Nalidixic acid selectively inhibited deoxyribonucleic acid (DNA) synthesis in cultures of Escherichia coli15TAU. Protein and ribonucleic acid synthesis were shown to be a prerequisite for the bactericidal action of the drug. This action can be prevented by means of inhibitors at bacteriostatic concentrations. Both chloramphenicol, which inhibits protein synthesis, and dinitrophenol, which uncouples oxidative phosphorylation, effectively prevented the bactericidal action of nalidixic acid on E. coli. The lethal action of nalidixic acid also was controlled by transfer of treated cells to drug-free medium. DNA synthesis resumed immediately upon removal of the drug and was halted immediately by retreatment. These studies indicate that nalidixic acid acts directly on the replication of DNA rather than on the “initiator” of DNA synthesis. The entry of nalidixic acid into cells of E. coliwas not dependent upon protein synthesis. Even in the presence of an inhibiting concentration of chloramphenicol, nalidixic acid prevented DNA synthesis by E. coli15TAU.

Prior treatment of Escherichia coliwith nalidixic acid in nutritionally complete medium altered the subsequent pattern of deoxyribonucleic acid (DNA) synthesis normally observed in nutritionally deficient medium. Transfer of E. coli15 TAU to an amino acid- and pyrimidine-deficient medium usually resulted in a 40 to 50% increase in DNA content. Previous treatment with nalidixic acid caused a 200 to 300% increase in DNA content under these conditions. The extent of this DNA synthesis depended on the duration of prior exposure to nalidixic acid. The maximal rate of synthesis was obtained after a 40- to 60-min exposure to nalidixic acid and was two to three times that of the control. The inductionof this excessive DNA synthesis was prevented by chloramphenicol or phenethyl alcohol, but the synthesisof this DNA was only partially sensitive to these agents. With E. coliTAU-bar, the rate of DNA synthesis, after removal of nalidixic acid, was similar to that of E. coli15 TAU, but the maximal amount of DNA synthesized was 180 to 185% of that initially present. Cesium chloride density gradient analysis demonstrated that DNA synthesis after removal of nalidixic acid occurs by a semiconservative mode of replication. The density distribution of this DNA was similar to that obtained after thymine starvation. These results suggest that nalidixic acid treatment may induce additional sites for DNA synthesis in E.coli.

Cook, ThomasM. (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), Karen G. Brown, James V. Boyle, and William A. Goss. Bactericidal action of nalidixic acid on Bacillus subtilis. J. Bacteriol. 92:1510–1514. 1966.—Nalidixic acid at moderate concentrations exerts a bactericidal action upon the gram-positive bacterium Bacillus subtilis. The synthesis of deoxyribonucleic acid (DNA) in B. subtilisis selectively inhibited by nalidixic acid at concentrations approximating the minimal growth inhibitory concentration. Higher concentrations (25 μg/ml) result in a 30 to 35% degradation of DNA. After extended exposure to nalidixic acid, protein synthesis is also depressed. Cells of B. subtilistreated with nalidixic acid exhibit characteristic morphological abnormalities including cell elongation and development of gram-negative areas. From the results presented, it can be concluded that the mode of action of nalidixic acid upon susceptible bacteria is similar for both gram-positive and gram-negative species.

Goss, WilliamA. (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Deitz, and Thomas M. Cook. Mechanism of action of nalidixic acid on Escherichia coli. II. Inhibition of deoxyribonucleic acid synthesis. J. Bacteriol. 89:1068–1074. 1965.—Nalidixic acid was shown to inhibit specifically the synthesis of deoxyribonucleic acid (DNA) in Escherichia coli. Slight effects on protein and ribonucleic acid (RNA) synthesis were observed only at higher levels of drug or after prolonged incubation. The inhibition of DNA synthesis in E. coli15TAU, as measured by incorporation of C14-labeled thymine, was observed after exposure to nalidixic acid for 10 min. Inhibition of the incorporation of C14-labeled uracil into RNA and C14-labeled l-arginine into protein (21 and 28% inhibition, respectively) was observed only after 60 min of exposure. When cultures of E. coli15TAU were exposed to 3.0 μg/ml of nalidixic acid (slightly greater than the minimal growth inhibitory concentration), the incorporation of C14-labeled thymidine was inhibited 30 to 40% after 90 min. Nalidixic acid at 10 μg/ml, a lethal concentration, inhibited thymidine incorporation 72% during this period. Nalidixic acid at 1.0 μg/ml had no apparent effect on the incorporation of C14-labeled adenine or C14-labeled uracil into RNA of cultures of E. coli198, a wild-type strain. However, incorporation of both bases into DNA was strongly inhibited after 60 min of exposure (66 and 69%, respectively). Nalidixic acid inhibited DNA replication during a single round of synthesis. In contrast with “thymineless death,” nalidixic acid was not lethal to E. coli15TAU during restricted RNA and protein synthesis (i.e., in a medium containing thymine but lacking arginine and uracil). We have shown also that this chemotherapeutic agent has little effect on the synthesis of protein or RNA required to initiate DNA replication. After 75 min of inhibition, the capacity of E. coli15TAU to synthesize DNA in a medium containing thymine, arginine, and uracil may be restored by a simple filtration and washing process, indicating that the drug is not firmly bound. These studies leave little doubt that a primary action of nalidixic acid is the inhibition of the synthesis of DNA in E. coli.

Goss, William A.(Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Dietz, and Thomas M. Cook. Mechanism of action of nalidixic acid on Escherichia coli. J. Bacteriol. 88:1112–1118. 1964.—Nalidixic acid was lethal for proliferating cultures of Escherichia coli. Associated with this lethal effect was the formation of elongated, serpentine forms. Cultures treated with nalidixic acid were osmotically stable; lethality was observed in the presence of stabilizers. Although it was possible to demonstrate leakage of intracellular components from treated cells, this effect occurred only after 99% of the cells were nonviable. Nalidixic acid had little or no effect on respiration with glucose as substrate. If cellular growth was restricted by suboptimal temperature or nutritional deficiencies, the drug was not lethal. Chemical analysis of cellular constituents revealed that lipid, protein, and ribonucleic acid levels were of the same order of magnitude in control and drug-treated cells. Only deoxyribonucleic acid (DNA) levels were markedly lowered in drug-treated cells. These facts are consistent with the view that nalidixic acid interferes with the synthesis of E. coliDNA.