首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
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 coli 15TAU. 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. coli was not dependent upon protein synthesis. Even in the presence of an inhibiting concentration of chloramphenicol, nalidixic acid prevented DNA synthesis by E. coli 15TAU.  相似文献   

2.
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 coli 15TAU 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.  相似文献   

3.
Bactericidal action of nalidixic acid on Bacillus subtilis   总被引:21,自引:9,他引:12  
Cook, Thomas M. (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. subtilis is selectively inhibited by nalidixic acid at concentrations approximating the minimal growth inhibitory concentration. Higher concentrations (25 mug/ml) result in a 30 to 35% degradation of DNA. After extended exposure to nalidixic acid, protein synthesis is also depressed. Cells of B. subtilis treated 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.  相似文献   

4.
Western (immunoblot) analysis using Escherichia coli anti-RecA antiserum revealed that expression of the RecA protein of Pseudomonas aeruginosa PAO is induced upon exposure of the bacterium to UV irradiation or norfloxacin, a quinolone related to nalidixic acid.  相似文献   

5.
Our earlier finding that the radioprotective action of 2-mercaptoethylamine (MEA) is counteracted by ascorbate suggests a biochemical mechanism of action, which is supported by observations that MEA is not radioprotective in Rec- E. coli strains. In this study we show that MEA inhibits the induction of the recA gene by UV- or gamma-irradiation or by nalidixic acid in Escherichia coli strain GE94, which contains a recA-lacZ fusion. This effect, which may be counteracted by cysteine, indicates that in general MEA inhibits the induction of SOS functions.  相似文献   

6.
The effect of nalidixic acid on the growth of various deoxyribonucleic acid (DNA) bacteriophages has been investigated by one-step growth experiments. The Escherichia coli bacteriophages T5, lambda, T7 and phiR are strongly inhibited by nalidixic acid, whereas T4 and T2 are only partially inhibited. The Bacillus subtilis bacteriophages SP82, SP50, and phi29 are relatively unaffected by nalidixic acid. There is no correlation between those bacteriophages which can grow in the presence of nalidixic acid and the presence of an unusual base in the phage DNA.  相似文献   

7.
The synthesis of maltodextrin phosphorylase and the phage λ receptor of Escherichia coli K-12 is substantially inhibited by the presence of 50 μg nalidixic acid/ml in the culture medium. β-galactosidase synthesis is inhibited to a lesser extent and no inhibition of L-tryptophanase synthesis is observed. The inhibition of enzyme synthesis is apparently not due to the effect of nalidixic acid on deoxyribonucleic acid synthesis.  相似文献   

8.
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 coli ATCC 11229 and E. coli 15TAU. Nalidixic acid had no inhibitory effect on the DNA-polymerase of the wild-type strain E. coli ATCC 11229 at concentrations of 1.4 x 10(-3) to 2.8 x 10(-3)m. No inhibition of deoxyribonucleotide kinase activity was observed at concentrations of nalidixic acid ranging from 2 x 10(-3) to 8.6 x 10(-3)m. Nalidixic acid (0.43 x 10(-4) to 0.43 x 10(-3)m) had no inhibitory effect on the deoxyribosyl transferase activity of crude extracts obtained from E. coli ATCC 11229 or E. coli 15TAU. Analytical CsCl density gradient centrifugation demonstrated that the DNA obtained after treatment of E. coli 15TAU 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.  相似文献   

9.
The effect of low concentrations of nalidixic acid on ribonucleic acid (RNA) synthesis in Escherichia coli was examined. It was observed that RNA synthesis in exponentially growing cells was not significantly affected, in harmony with previous studies. However, RNA synthesis was markedly depressed by nalidixic acid during starvation for an amino acid or during chloramphenicol treatment. This effect was not caused by increased killing or inhibition of nucleoside triphosphate synthesis by nalidixic acid. The pattern of radioactive uracil incorporation into transfer RNA or ribosomes was not changed by the drug. The sensitivity of RNA synthesis to nalidixic acid in the absence of protein production may be useful in probing the amino acid control of RNA synthesis.  相似文献   

10.
Rifampicin, but not chloramphenicol or other inhibitors of translation, inhibited EDTA-induced autolysis in Escherichia coli. Inhibition of EDTA-induced autolysis in E. coli was also observed with nalidixic acid and novobiocin, inhibitors of topoisomerase II. Rifampicin or nalidixic acid-resistant mutants of E. coli were resistant to the inhibitory effect of the respective antibiotic on EDTA-induced autolysis. The implications of these studies in regard to our understanding of the regulation of autolysis in E. coli are discussed.  相似文献   

11.
Abstract Nalidixic acid caused a significant increase in the Mn-containing superoxide dismutase (MnSOD) of Escherichia coli . The maximum stimulatory effect of nalidixic acid on MnSOD biosynthesis was observed at 0.1 mM. The stimulatory effect of nalidixic acid was not due to increases in the intracellular flux of O2, but rather to its ability to chelate Fe2+. Furthermore, 2,2'-dipyridyl and 1,10-phenanthroline were shown to cause a 7- to 20-fold increase in the MnSOD of E. coli . It is proposed that the repressor for MnSOD is an iron-containing protein.  相似文献   

12.
Letuta  U. G.  Binder  A. S.  Tikhonova  T. A. 《Microbiology》2020,89(3):273-277
Microbiology - The effect of 25Mg, a magnetic magnesium isotope, on the sensitivity of Escherichia coli K12 TG1 to quinolone/fluoroquinolone (nalidixic acid and ciprofloxacin) and aminoglycoside...  相似文献   

13.
DNA gyrase (Topoisomerase II) from Pseudomonas aeruginosa   总被引:13,自引:0,他引:13  
DNA gyrase (Topoisomerase II) has been purified from Pseudomonas aeruginosa strain PAO. This enzyme is inhibited by novobiocin and nalidixic acid. DNA gyrase from P. aeruginosa is resistant to a much higher level of nalidixic acid than is Escherichia coli DNA gyrase. This increased level of resistance may explain, at least in part, the higher levels of natural resistance exhibited by P. aeruginosa toward nalidixic acid.  相似文献   

14.
The high antibacterial activity of nalidixic acid against Escherichia coli, cultivated in raw and pasteurized milk has been shown. The low oxygen reduction potential had no influence on the antibacterial activity of this drug. The natural antibacterial agents in active milk from an inflamed udder have reduced the efficacy of nalidixic acid inhibition of the growth of E. coli.  相似文献   

15.
In order to determine the existence of synergism, the bacteriostatic action of flavonoids against Escherichia coli ATCC 25 922 between dihydroxylated chalcones and a clinically interesting conventional antibiotic, binary combinations of 2′,3-dihydroxychalcone, 2′,4-dihydroxychalcone and 2′,4′-dihydroxychalcone with nalidixic acid and its ternary combinations with rutin (inactive flavonoid) were assayed against this Gram negative bacterium. Using a kinetic-turbidimetric method, growth kinetics were monitored in broths containing variable amounts of dihydroxychalcone alone, combinations of dihydroxychalcone variable concentration–nalidixic acid constant concentration and dihydroxychalcone variable concentration–nalidixic acid constant concentration–rutin constant concentration, respectively. The minimum inhibitory concentrations of dihydroxychalcones alone and its binary and ternary combinations were evaluated. All chalcones, and their binary and ternary combinations showed antibacterial activity, being rutin an excellent synergizing for the dihydroxychalcone–nalidixic acid binary combination against E. coli ATCC 25 922. Thus, this synergistic effect is an important way that could lead to the development of new combination antibiotics against infections caused by E. coli.  相似文献   

16.
Nalidixic Acid-Resistant Auxotrophs of Escherichia coli   总被引:2,自引:2,他引:0       下载免费PDF全文
purB and ctr mutants of Escherichia coli are resistant to low levels of nalidixic acid.  相似文献   

17.
The synthesis of L-serine deaminase in Escherichia coli K-12 was induced after exposure of cells to a variety of DNA-damaging agents, including UV irradiation, nalidixic acid, and mitomycin C. Synthesis was also induced during growth at high temperature. A mutant constitutive for SOS functions showed an elevated level of L-serine deaminase activity. The response to DNA-damaging agents thus may be mediated via the SOS system.  相似文献   

18.
Short periods of incubation in medium containing nalidixic acid or hydroxyurea, followed by a return to normal growth conditions, induced filament formation in Escherichia coli B (fil(+)) and AB1899NM (lon(-)) but not in B/r (fil(-)) and AB1157 (lon(+)). These drugs reversibly stopped deoxyribonucleic acid (DNA) synthesis with little or no effect on ribonucleic acid (RNA) synthesis or mass increase. The initial imbalance caused by incubation in these drugs was the same for B and B/r as was macromolecular synthesis following a return to normal growth conditions. DNA degradation caused by nalidixic acid was measured and found to be the same for B and B/r. Hydroxyurea caused no DNA degradation in these two strains. Survival curves as determined under various conditions by colony formation suggested that the property of filament formation was responsible for the extrasensitivity of fil(+) and lon(-) strains to either nalidixic acid or hydroxyurea. E. coli B was more sensitive to either drug than was B/r or B(s-1). Pantoyl lactone or liquid holding treatment aided division and colony formation of nalidixic acid-treated B but had no effect on B/r. Likewise, the filament-former AB1899NM was more sensitive to nalidixic acid than was the non-filament-former AB1157. The sensitivity of B/r and B(s-1) to nalidixic acid was nearly the same except at longer times in nalidixic acid, when B(s-1) appeared more resistant. Even though nalidixic acid, hydroxyurea, and ultraviolet light may produce quite different molecular alterations in E. coli, they all cause a metabolic imbalance resulting in a lowered ratio of DNA to RNA and protein. We propose that it is this imbalance per se rather than any specific primary chemical or photochemical alterations which leads to filament formation by some genetically susceptible bacterial strains such as lon(-) and fil(+).  相似文献   

19.
The ability of several Escherichia coli strains deficient in recombination (rec) to survive in the presence of nalidixic acid was determined. Genetic blocks of the RecBC or the RecF pathways resulted in increased sensitivity to nalidixic acid when compared with the wild-type strain. Mutants lacking functional recA, recL, or recB recC recF genes showed the most rapid decrease in colony-forming ability when incubated with nalidixic acid. However, the uvrB gene also plays a role in maintaining cell viability.  相似文献   

20.
icd Mutants of Escherichia coli K-12, selected for their resistance to nalidixic acid, are deficient in isocitrate dehydrogenase.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号