Extracellular pH has been assumed to play little if any role in how bacteria respond to antibiotics and antibiotic resistance development. Here, we show that the intracellular pH of Escherichia coli equilibrates to the environmental pH following treatment with the DNA damaging antibiotic nalidixic acid. We demonstrate that this allows the environmental pH to influence the transcription of various DNA damage response genes and physiological processes such as filamentation. Using purified RecA and a known pH-sensitive mutant variant RecA K250R we show how pH can affect the biochemical activity of a protein central to control of the bacterial DNA damage response system. Finally, two different mutagenesis assays indicate that environmental pH affects antibiotic resistance development. Specifically, at environmental pH's greater than six we find that mutagenesis plays a significant role in producing antibiotic resistant mutants. At pH's less than or equal to 6 the genome appears more stable but extensive filamentation is observed, a phenomenon that has previously been linked to increased survival in the presence of macrophages.

• MeSH
• antibakteriální látky farmakologie   MeSH
• Escherichia coli účinky léků   genetika   účinky záření   MeSH
• koncentrace vodíkových iontů MeSH
• kyselina nalidixová farmakologie   MeSH
• mikrobiální viabilita účinky léků   účinky záření   MeSH
• nestabilita genomu účinky léků   genetika   účinky záření   MeSH
• poškození DNA účinky léků   genetika   účinky záření   MeSH
• propidium farmakologie   MeSH
• průtoková cytometrie MeSH
• retardační test MeSH
• rifampin farmakologie   MeSH
• ultrafialové záření MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• kyselina nalidixová MeSH
• propidium MeSH
• rifampin MeSH

Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of paratuberculosis in ruminants, has a lipid-rich cell wall which facilitates its survival and persistence in the environment. This property of the organism is exploited when it is cultured as decontaminating agents and antibiotics are used to suppress the growth of contaminating microflora, but such treatments can also negatively affect the isolation of MAP itself. The objective of this study was to assess the effect of the 'VAN' antibiotics (vancomycin, amphotericin B and nalidixic acid) on the viability of MAP using a propidium monoazide real time quantitative PCR (PMA qPCR) and culture. Long-term (5 week) treatment with VAN antibiotics resulted in a larger decrease in bacterial numbers compared to short-term (3 day) exposure. The PMA qPCR assay indicated that 50 μg/mL of vancomycin, 50 μg/mL of nalidixic acid, and 200 μg/mL of amphotericin B were 'threshold' concentrations, respectively, above which the decline in the viability of MAP was statistically significant. Using culture, these threshold concentrations were 100 μg/mL of vancomycin, 50-100 μg/mL of nalidixic acid, and 100 μg/mL of amphotericin B, respectively. Given that the two methods were found to be comparable, the PMA qPCR is a potentially more convenient and effective alternative to culture in detecting MAP.

• MeSH
• amfotericin B farmakologie   MeSH
• antibakteriální látky farmakologie   MeSH
• azidy metabolismus   MeSH
• časové faktory MeSH
• kvantitativní polymerázová řetězová reakce metody   MeSH
• kyselina nalidixová farmakologie   MeSH
• Mycobacterium avium subsp. paratuberculosis účinky léků   růst a vývoj   izolace a purifikace   metabolismus   MeSH
• paratuberkulóza diagnóza   mikrobiologie   MeSH
• počet mikrobiálních kolonií metody   MeSH
• přežvýkavci mikrobiologie   MeSH
• propidium analogy a deriváty   metabolismus   MeSH
• vankomycin farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amfotericin B MeSH
• antibakteriální látky MeSH
• azidy MeSH
• kyselina nalidixová MeSH
• propidium monoazide MeSH Prohlížeč
• propidium MeSH
• vankomycin MeSH

The courses of rRNA accumulation, DNA replication, and nuclear division were followed both in the chloroplast and the nucleocytosolic compartments during the cell cycle in synchronized populations of the chlorococcal alga Scenedesmus quadricauda. Control and nalidixic acid-treated cultures were compared. Nalidixic acid (150 mg/L) was added either at the beginning of the cell cycle or consecutively during the cell cycle to subcultures transferred into the dark. If the inhibitor was applied at the beginning of the cell cycle, chloroplast DNA did not replicate and nucleoids did not divide. Chloroplast division, however, was coordinated in a timely fashion with cytokinesis even under conditions of blocked chloroplast DNA replication. While the growth rate was slowed down, the courses of reproductive processes in the nucleocytosolic compartment were not affected and their timing and the number of rounds were coordinated with growth rate as in the control culture. The rate of cytosolic rRNA synthesis was lower but no apparent effect was seen on the amount of rRNA that accumulated during the cell cycle. In contrast, lower levels of chloroplast rRNA were found at the end of the cell cycle compared with the control culture. Experiments in which cells were transferred to the dark during the cell cycle showed that the inhibitor affected none of the reproductive events in the nucleocytosolic compartment. In the chloroplast compartment, DNA replication was inhibited in inhibitor-treated cultures, but was unaffected in controls. The chloroplast nucleoids themselves divided even in the presence of the inhibitor, reducing their DNA content to a level which corresponded to that in freshly formed control daughter cells.

• MeSH
• chloroplasty účinky léků   MeSH
• kyselina nalidixová farmakologie   MeSH
• Scenedesmus účinky léků   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyselina nalidixová MeSH

Two plasmid-harboring strains of Micrococcus sp. (M-36 and AG-43) degrade malathion and chlorpyriphos. Derivatives of the strains (SDS-36 and AO-43) treated with acridine orange and sodium dodecyl sulfate could not utilize malathion and chlorpyriphos for growth as the sole carbon source. Agarose gel electrophoresis of cell extracts of M-36 and AG-43 revealed the presence of a plasmid which was absent in SDS-36 and AO-43--suggesting probable involvement of plasmids in the degradation of malathion and chlorpyriphos by M-36 and AG-43. Nalidixic acid resistance in M-36 was also lost upon elimination of plasmids.

• MeSH
• akridinová oranž farmakologie   MeSH
• antibiotická rezistence genetika   MeSH
• antiinfekční látky farmakologie   MeSH
• biodegradace MeSH
• dursban metabolismus   MeSH
• elektroforéza v agarovém gelu MeSH
• kyselina nalidixová farmakologie   MeSH
• látky znečišťující půdu metabolismus   MeSH
• malathion metabolismus   MeSH
• Micrococcus účinky léků   genetika   metabolismus   MeSH
• plazmidy fyziologie   MeSH
• rezidua pesticidů metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• akridinová oranž MeSH
• antiinfekční látky MeSH
• dursban MeSH
• kyselina nalidixová MeSH
• látky znečišťující půdu MeSH
• malathion MeSH
• rezidua pesticidů MeSH

A series of novel derivatives of 4H-pyrido[1,2-]pyrimidine, 1,4-dihydro-4-oxo-1,5-naphthyridine and 1,4-dihydro-4-oxo-1,6-naphthyridine were prepared and their biological activity was compared with that of nalidixic acid. The in vitro antibacterial activity of the tested compounds was lower than that of nalidixic acid except for two agents, 1b and 2c, with a higher activity against Enterococcus faecalis. The compounds were tested for their ability to cure four plasmids from two species of Enterobacteriaceae. The derivatives eliminated three plasmids (pKM101, pBR322, F'lac) at one-half or one-quarter of the minimal inhibitory concentration. Plasmid RP4 was unaffected by the treatment. None of these compounds showed better antichloroplast activity than nalidixic acid.

• MeSH
• antiinfekční látky chemie   farmakologie   MeSH
• aza sloučeniny chemie   farmakologie   MeSH
• chinolony chemie   farmakologie   MeSH
• Enterobacteriaceae účinky léků   MeSH
• Euglena gracilis účinky léků   MeSH
• kyselina nalidixová farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• plastidy účinky léků   MeSH
• plazmidy účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antiinfekční látky MeSH
• aza sloučeniny MeSH
• chinolony MeSH
• kyselina nalidixová MeSH

Inducible stable DNA replication (iSDR) provoked by a damaging treatment with MMS, MNU, MNNG, NFAA, NFN, 4NQO, NAL or MMC, was followed in both repair-competent E. coli PQ35 and its uvrA derivative E. coli PQ37. In contrast to SOS-inducible mutagenesis, which is more pronounced in excision-deficient cells, iSDR was more obvious in repair-competent cells. This may be due to special features of iSDR and need not indicate involvement of the uvrA gene product in it.

• MeSH
• 4-chinolony MeSH
• 4-nitrochinolin-1-oxid farmakologie   MeSH
• akryláty farmakologie   MeSH
• antiinfekční látky MeSH
• chloramfenikol farmakologie   MeSH
• dusíkaté sloučeniny farmakologie   MeSH
• Escherichia coli genetika   MeSH
• furany farmakologie   MeSH
• kyselina nalidixová analogy a deriváty   farmakologie   MeSH
• methylmethansulfonát farmakologie   MeSH
• methylnitronitrosoguanidin farmakologie   MeSH
• methylnitrosomočovina farmakologie   MeSH
• mitomycin farmakologie   MeSH
• mutageny farmakologie   MeSH
• nitrofurany farmakologie   MeSH
• replikace DNA účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 4-chinolony MeSH
• 4-nitrochinolin-1-oxid MeSH
• 5-nitro-2-furfuryl nitrate MeSH Prohlížeč
• akryláty MeSH
• antiinfekční látky MeSH
• chloramfenikol MeSH
• citrated nalidixic acid MeSH Prohlížeč
• dusíkaté sloučeniny MeSH
• furany MeSH
• kyselina nalidixová MeSH
• methylmethansulfonát MeSH
• methylnitronitrosoguanidin MeSH
• methylnitrosomočovina MeSH
• mitomycin MeSH
• mutageny MeSH
• nitrofurany MeSH
• nitrofurylacrylic acid MeSH Prohlížeč

• MeSH
• antibakteriální látky MeSH
• bakteriurie mikrobiologie   MeSH
• Enterobacteriaceae účinky léků   MeSH
• kyselina nalidixová farmakologie   MeSH
• kyselina oxolinová farmakologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• ofloxacin farmakologie   MeSH
• Pseudomonas účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antibakteriální látky MeSH
• kyselina nalidixová MeSH
• kyselina oxolinová MeSH
• ofloxacin MeSH

UV irradiated E. coli cells contain alkali labile sites in their DNA daughter chains. It is shown here that the occurrence of alkali labile sites in the newly synthesized DNA is a more common phenomenon. It occurred after treatment with two different DNA damaging chemicals, but not after treatment with nalidixic acid.

• MeSH
• DNA bakterií biosyntéza   účinky léků   MeSH
• Escherichia coli účinky léků   genetika   účinky záření   MeSH
• kyselina nalidixová farmakologie   MeSH
• methylnitrosomočovina farmakologie   MeSH
• mitomycin MeSH
• mitomyciny farmakologie   MeSH
• poškození DNA MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• kyselina nalidixová MeSH
• methylnitrosomočovina MeSH
• mitomycin MeSH
• mitomyciny MeSH

The initial replication region of the chromosome on the replication map of M. phlei constructed by means of sequential mutagenesis in synchronous populations was accurately determined. By following the time shift of the replication moment of the genes bac and met in the control culture and in the culture with the initial inhibition of DNA synthesis by nalidixic acid the start of replication of the chromosome was determined at 15 min before replication of the gene ile. On the basis of the results obtained a scheme of the cell cycle in M. phlei was proposed. Intervals C and D depend on the generation time, become prolonged independently of each other and assume the whole cycle. The ratio C/(C + D) equals to 0.56 and the interval D has a value of 0.76 of the interval C. The mutual ratio of the intervals C : D is 1.3 : 1.0. The obtained results make it possible to form the assumption about mutual ratios between the chromosome replication and cell division in bacteria exhibiting slow growth rates.

• MeSH
• bakteriální chromozomy MeSH
• buněčný cyklus MeSH
• časové faktory MeSH
• DNA bakterií biosyntéza   MeSH
• Escherichia coli cytologie   MeSH
• kyselina nalidixová farmakologie   MeSH
• Mycobacterium phlei cytologie   genetika   MeSH
• Mycobacterium cytologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• kyselina nalidixová MeSH

Partial inhibition of DNA synthesis stimulates the production of inorganic diphosphatase in Escherichia coli but the changes in diphosphate (PPi) level observed did not correlate with the enzyme activity. An accumulation of PPi was observed in the presence of inhibitors of RNA synthesis or nucleotide synthesis. In the former case the level of the enzyme did not change but in the latter case it increased. Thus the amount of inorganic diphosphatase alone does not determine the concentration of PPi in E. coli.

• MeSH
• anorganická pyrofosfatasa MeSH
• difosfáty metabolismus   MeSH
• Escherichia coli účinky léků   enzymologie   genetika   MeSH
• fluoruracil farmakologie   MeSH
• genetická transkripce účinky léků   MeSH
• kinetika MeSH
• kyselina nalidixová farmakologie   MeSH
• mutace MeSH
• pyrofosfatasy genetika   metabolismus   MeSH
• replikace DNA účinky léků   MeSH
• uracil analogy a deriváty   farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anorganická pyrofosfatasa MeSH
• azauracil MeSH Prohlížeč
• difosfáty MeSH
• fluoruracil MeSH
• kyselina nalidixová MeSH
• pyrofosfatasy MeSH
• uracil MeSH