Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex ...Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex forms.This study investigated the spectral properties of three fluoroquinolones(FQs)with and without metal ions Fe(III),Cu(II),and Al(III)in solutions under different pH conditions,as well as evaluated the changes in toxicity due to the complex with thesemetal ions using luminescent bacteria(vibrio fischeri).FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions,and the formation of complexes weakened the ultravioletabsorbing ability of FQs.At pH=7.0,Cu(II)quenched the fluorescence intensity of FQs.Moreover,their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored,revealing that the coordination sites of Cu(II)in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom.This conclusion was further verified by the theory of molecular surface electrostatic potential.In addition,except for complexes of ciprofloxacin-metals,enhanced toxicity of FQs upon coordination with Fe(III)was observed,while reduced toxicity was found for coordination with Cu(II)and Al(III).These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions.展开更多
Objectives: To determine the susceptibilities of M.hominis and U. urealyticum to fluoroquinolones forthe instruction of reasonable clinical application ofantibiotics.Method: The susceptibilities of M. hominis and U.ur...Objectives: To determine the susceptibilities of M.hominis and U. urealyticum to fluoroquinolones forthe instruction of reasonable clinical application ofantibiotics.Method: The susceptibilities of M. hominis and U.urealyticum to six fluoroquinolones were determinedby the broth dilution method.Results: Sparfloxacin and gatifloxacin were veryactive with MIC50S of 0.03125 and 0.25 μg/ml againstM. hominis, 0.25 and 0.5 μg/ml against U. urealyticum,respectively. Levofloxacin and ofloxacin had MIC50S of1 μg/ml and 2 μg/ml, respectively against both species.Norfloxacin was less effective against both species at16 and 32 μg/ml. Ciprofloxacin was unusual in thatthe MIC50S varied fourfold between species, with 2 μg/ml against M. hominis and 8 μg/ml against U.urealyticum.Conclusions: The results can provide useful infor-mation for selecting fluoroquinolones for treatmentof urogenital mycoplasma infections.展开更多
Modified 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC)method was employed to synthesize the artificial antigen of norfloxacin(NOR),and New Zealand rabbits were used to produce anti-NOR polyclonal antibody(pAb).Ba...Modified 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC)method was employed to synthesize the artificial antigen of norfloxacin(NOR),and New Zealand rabbits were used to produce anti-NOR polyclonal antibody(pAb).Based on the checkerboard titration,an indirect competitive enzyme-linked immunosorbent assay(icELISA) standard curve was established.This assay was sensitive and had a working range from 0.12 to 68.40 ng/ml,with the half maximal inhibitory concentration(IC50)and limit of detection(LOD)values of 2.7 ng/ml and 0.06 ng/ml,respectively.The produced pAb exhibited high cross-reactivity to fluoroquinolones(FQs)tested,and the IC50 values to enoxacin,ciprofloxacin,and pefloxacin were 3.1,3.4,and 4.1 ng/ml,respectively.It also indicated that the concentrations of NaOH and methanol in assay buffer should not be higher than 10%and 30%.When spiked in milk at 5,20,and 50 ng/ml,the recoveries for NOR,enoxacin,ciprofloxacin,and pefloxacin ranged 90.5%-98.0%,84.0%-95.2%,94.0%-106.0%,and 89.5%-100.0%,respectively.The results suggest that this class-specific pAb-based icELISA could be utilized for the primary screening of FQ residues in animal-original products.展开更多
An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high p...An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high performance liquid chromatography (HPLC) with diode array detection (DAD) is developed to effectively determine two fiuoroquinolones (enoxacin and lomefioxacin), two sulfonamides (sulfanilamide and sulfamethoxazole) and one tetracycline (tetracycline) simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v). Solvent acetonitrile and solvent acetic acid (0.1%) were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a fiow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 mg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs) (below 6.1%, nfi3) and the limits of quantitation (LOQ) ranged from 7 mg/kg to 34 mg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described.展开更多
To further explore an efficient modified route for the shift from an antibacterial fluoroquinolone to an antitumor one,mono-Schiff bases 6a-6h related to ciprofloxacin C3 carbonylhydrazone and bis-Schiff bases 4a-4h c...To further explore an efficient modified route for the shift from an antibacterial fluoroquinolone to an antitumor one,mono-Schiff bases 6a-6h related to ciprofloxacin C3 carbonylhydrazone and bis-Schiff bases 4a-4h corresponding to C3/C7 carbonylhydrazone/hydrazone attached on a skeleton of ciprofloquinolone were designed and synthesized,and their in vitro antitumor activity against CHO,HL60,L1210 cells and antibacterial activity against Staphylococcus aureus and Escherichia coli were also reported.展开更多
Solid organ transplantation(SOT)is the best treatment option for end-stage organ disease.Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection,particular...Solid organ transplantation(SOT)is the best treatment option for end-stage organ disease.Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection,particularly due to the reactivation of latent infections due to opportunistic agents such as Mycobacterium tuberculosis.Active tuberculosis(TB)after SOT is a significant cause of morbidity and mortality.Most cases of posttransplant TB are secondary to reactivation of latent tuberculosis infection(LTBI)due to the effects of long-term immunosuppressive therapy.Risk minimization strategies have been developed to diagnose LTBI and initiate treatment prior to transplantation.Isoniazid with vitamin B6 supplementation is the treatment of choice.However,liver transplantation(LT)candidates and recipients have an increased risk of isoniazid-induced liver toxicity,leading to lower treatment completion rates than in other SOT populations.Fluoroquinolones(FQs)exhibit good in vitro antimycobacterial activity and a lower risk of drug-induced liver injury than isoniazid.In the present review,we highlight the disease burden posed by posttransplant TB and summarize the emerging clinical evidence supporting the use of FQs for the treatment of LTBI in LT recipients and candidates.展开更多
To discover an efficient route for the shift from an antibacterial fluoroquinolone to an antitumor one based on the mechanistic similarities between targeting topoisomerases and the eukaryotic ones,two series of the t...To discover an efficient route for the shift from an antibacterial fluoroquinolone to an antitumor one based on the mechanistic similarities between targeting topoisomerases and the eukaryotic ones,two series of the title compounds,C3 bis-oxadiazole methylsulfides 6a―6h and corresponding dimethylpiperazinium iodides 7a―7h derived from levofloxacin 1 were designed and synthesized.Their in vitro antiproliferative activities against Chinese hamster ovary cell line（CHO）,murine leukemia cell line（L1210） and human leukocytoma cell line（HL60） were evaluated by MTT assay,and inhibitory effect on DNA topoisomerase IIα was also measured by means of densitometric assay.展开更多
Helicobacter pylori (H. pylori) is a widespread pathogen infecting about 40% of people living in urban areas and over 90% of people living in the developing regions of the world. H. pylori is well-documented as the ma...Helicobacter pylori (H. pylori) is a widespread pathogen infecting about 40% of people living in urban areas and over 90% of people living in the developing regions of the world. H. pylori is well-documented as the main factor in the pathogenesis of peptic ulcer disease, chronic gastritis, and gastric malignancies such as cancer and mucosa-associated lymphoid tissue-lymphoma; hence, its eradication is strongly recommended. The Maastricht IV consensus, which focused on the management of H. pylori infection, set important new strategies in terms of treatment approaches, particularly with regards to first- and second-line treatment protocols and led to improved knowledge and understanding of H. pylori resistance to antibiotics. In recent years, various fluoroquinolone-based protocols, mainly including levofloxacin, have been proposed and effectively tested at all therapeutic lines for H. pylori eradication. The aim of the present paper is to review the scientific literature focused on the use of fluoroquinolones in eradicating H. pylori.展开更多
The detailed sorption steps and biodegradation characteristics of fluoroquinolones （FQs） including ciprofloxacin, enrofloxacin, lomefloxacin, norfloxacin, and ofioxacin were investigated through batch experiments. T...The detailed sorption steps and biodegradation characteristics of fluoroquinolones （FQs） including ciprofloxacin, enrofloxacin, lomefloxacin, norfloxacin, and ofioxacin were investigated through batch experiments. The results indicate that FQs at a total concentration of 500 μg/L caused little inhibition of sludge bioactivity. Sorption was the primary removal pathway of FQs in the activated sludge process, followed by biodegradation, while hydrolysis and volatilization were negligible. FQ sorption on activated sludge was a reversible process governed by surface reaction, Henry and Freundlich models could describe the FQ sorption isotherms well in the concentration range of 100-300 μg/L. Thermodynamic parameters revealed that FQ sorption on activated sludge is spontaneous, exothermic, and enthalpy-driven. Hydrophobicity-independent mechanisms determined the FQ sorption affinity with activated sludge. The zwitterion of FQs had the strongest sorption affinity, followed by cation and anion, and aerobic condition facilitated FQ sorption. PQs were slowly biodegradable, with long half-lives （〉100 hr）. FQ biodegradation was enhanced with increasing temperature and under aerobic condition, and thus was possibly achieved through co-metabolism during nitrification. This study provides an insight into the removal kinetics and mechanism of FQs in the activated sludge process, but also helps assess the environmental risks of FQs resulting from sludge disposal.展开更多
In order to study the resistance of Neisseria （N.） gonorrhoeae to the fluoroquinolone and detect mutation patterns of quinolone resistance-determining regions （QRDRs） of clinical isolates in Shanghai, China, a tot...In order to study the resistance of Neisseria （N.） gonorrhoeae to the fluoroquinolone and detect mutation patterns of quinolone resistance-determining regions （QRDRs） of clinical isolates in Shanghai, China, a total of 80 clinical isolates of N. gonorrhoeae were consecutively collected from Shanghai. The MIC of fluoroquinolone for the isolates was examined by using the agar dilution method and the mutation profiles of the QRDRs of gyrA and parC were analyzed by sequencing and restriction fragment length polymorphism （RFLP）. Chi-square test was used for comparison of the t：nutation patterns. The results showed that： （1） High percentages of the 8 isolates were resistant to ciprofloxacin （95.0%）, ofloxacin （95.0%） and lomefloxacin （97.5%）, only one strain was susceptible to the ciprofloxacin. （2） Sensitive strains had a substitute of Asp95→Ala in the gyrA, and all isolates that were resistant or intermediated to the ciprofloxacin, had a double mutation in the gyrA （Ser91, Ala 92 and Asp95）. Some strains also had a mutation in the parC. （3） The MICs of these isolates were significantly associated with the mutation patterns in the gyrA and parC. A double mutation of gyrA combined with parC87 mutation was a predominant pattern in Shanghai and could mediate high level resistance to ciprofloxacin. It suggests that mutations in the QRDRs of gyrA and parC may be responsible for the fluoroquinolone resistance. And fluoroquinolone could not be used as the first line antibiotics for gonorrhea treatment any more in Shanghai, China.展开更多
Over the recent past,fluoroquinolone antibiotics(FQs)have raised extensive attention due to their potential to induce the formation of resistance genes and"superbugs",thus various advanced oxidation techniqu...Over the recent past,fluoroquinolone antibiotics(FQs)have raised extensive attention due to their potential to induce the formation of resistance genes and"superbugs",thus various advanced oxidation techniques have been developed to eliminate their release into the environment.In the present study,the prototype tetraamido macrocyclic ligand(Fe^Ⅲ-TAML)/hydrogen peroxide(H2O_(2))system is employed to degrade FQs(i.e.,norfloxacin and ciprofloxacin)over a wide p H range(i.e.,p H 6-10),and the reaction rate increases with the increase in p H level.The effect of dosage of Fe^Ⅲ-TAML and H2O_(2) on the degradation of FQs is evaluated,and the reaction rate is linearly correlated with the added amount of chemicals.Moreover,the impact of natural organic matters(NOM)on the removal of FQs is investigated,and the degradation kinetics show that both NOM type and experimental concentration exhibit negligible influence on the oxidative degradation of selected antibiotics.Based on the results of liquid chromatography-high resolution mass spectrometry and theoretical calculations,the reaction sites and pathways of FQs by Fe^Ⅲ-TAML/H2O_(2) system are further predicted and elucidated.展开更多
AIMTo compare the conjunctival epithelial toxicities of three newer-generation fluoroquinolones without preservatives.METHODSIn a prospective, randomized, double blind comparative study, 47 eyes of 47 patients with a ...AIMTo compare the conjunctival epithelial toxicities of three newer-generation fluoroquinolones without preservatives.METHODSIn a prospective, randomized, double blind comparative study, 47 eyes of 47 patients with a primary pterygium were enrolled, and divided randomly into three groups (levofloxacin 0.5%, gatifloxacin 0.3%, and moxifloxacin 0.5%). After pterygium surgery with the same conjunctival autograft technique, each patient maintained a regimen with a randomly assigned fluoroquinolone eye drop. Patients were examined every other day after surgery until the epithelium had completely healed. Photos were taken and used to measure the area of residual epithelial defects. Conjunctival healing time and speed (initial defect area/healing time (mm<sup>2</sup>/d) compared in each group using Kruskal-Wallis tests.RESULTSThere were no significant differences in mean age, gender, and conjunctival defect size of the donor site between these groups. However, the mean of conjunctival healing time and speed were statistically different in each group. The mean of conjunctival epithelial healing time was 8.93±2.69d (levofloxacin group), 10.31±2.96d (gatifloxacin group), and 13.50±4.10d (moxifloxacin group), P=0.006. The mean conjuctival epithelial healing speed was 6.18±1.39 mm<sup>2</sup>/d (levofloxacin group), 5.52±1.68 mm<sup>2</sup>/d (gatifloxacin group), and 4.40±1.30 mm<sup>2</sup>/d (moxifloxacin group), P=0. 003.CONCLUSIONWithout the influence of preservatives, levofloxacin and gatifloxacin might be less toxic to the regeneration of conjunctival epithelial cells and cause a faster conjunctival wound healing relative to moxifloxacin.展开更多
Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed p...Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed primers to amplify the Quinolone-resistance-determining region （QRDR） of gyrA and par（？,, then the PCR products were sequenced and analyzed. In comparision with NCTC5776, a single mutation was found at base 371 in gyrA of strain 38 which changed from C to T, and a single mutation was found at base 350 in gyrA of strain 60 which changed from A to C. No mutation was found in gyrA of the rest The mutation of strain 38 led to an amino acid substitution of Arg99Cys and the mutation of 60 led to an amino acid substitution of Met 92 Leu. No mutation was found in parC QRDR of all the isolates. These results indicats that the DNA gyrase will be the primary target to salmonella of fluoroquinolone.展开更多
Polymyxin B(PB),as the last-line of defense against multidrug-resistant Gram-negative bacteria,has caused resistance to P.aeruginosa recently.Fortunately,synergistic treatment could preserve the last class of antibiot...Polymyxin B(PB),as the last-line of defense against multidrug-resistant Gram-negative bacteria,has caused resistance to P.aeruginosa recently.Fortunately,synergistic treatment could preserve the last class of antibiotics and reduce the emergency of drug resistance.Here,we performed a screen of 970 approved drugs synergized with PB against the P.aeruginosa DK2,which is severely resistant to PB,MIC=512μg/mL.Encouragingly,we found fluoroquinolones could synergy with PB and achieved an obvious reduction in MIC of PB below the clinical susceptible breakpoint(2 μg/mL).Especially,gemifloxacin achieved the highest synergistic effect with PB,leading to a 4096-fold MIC reduction(reduced from512 μg/mL to 0.125 μg/mL).Furthermore,synergistic effect was also observed in the combination of gemifloxacin and colistin.Finally,outer membrane permeabilization assay showed that gemifloxacin could increase the permeability of bacterial cell membranes for P.aeruginosa which partly explained the synergy mechanism.These results indicate that fluoroquinolones represent attractive synergists to address the emerging threat of polymyxin-resistant infections.展开更多
To further expand an effective modified route for the shift from an antibacterial fluoroquinolone （FQ） to an antitumor FQ, two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fu...To further expand an effective modified route for the shift from an antibacterial fluoroquinolone （FQ） to an antitumor FQ, two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings, [ 1,2,4]triazolo[3,4- b][1,3,4]thiadiazine and pyrazolo[5,1-c][1,2,4]triazole, respectively, were designed and synthesized starting from the current antibacterial FQs, and their in vitro antitumor activity against L1210, CHO cell lines were evaluated via their respective IC50 values.展开更多
Aim: To determine the Plasmid DNA profile of the multidrug resistant strains of Pseudomonas aeruginosa in the clinical isolates. Materials and Methods: Of the 150 clinical samples (Ear swab, Urine, Wound swab, Sputa a...Aim: To determine the Plasmid DNA profile of the multidrug resistant strains of Pseudomonas aeruginosa in the clinical isolates. Materials and Methods: Of the 150 clinical samples (Ear swab, Urine, Wound swab, Sputa and Semen) received at Lahor Research Laboratory and Medical center in Benin City, between January 2010 and December 2012, 36 (24%) yielded significant growth of P. aeruginosa. Samples were cultured on MacConkey and Blood agar. Clinical isolates were identified using standard method. Antibiotics susceptibility test employing agar disc diffusion method was used. Clinical isolates were subjected to Plasmid DNA profiling and curing test was carried out at Lahor Molecular Laboratory. This was followed by a post plasmid curing susceptibility test. Agarose gel electrophoresis was carried out to separate the Plasmid DNA using standard method. Bands were visualized using UV illuminator. Results: Wound swabs had the highest numbers of clinical isolates of P. aeruginosa (55.6%) followed by Urine, Semen, Sputa and Ear swab (19.4%, 11.0%, 8.3%, and 5.6%) respectively. Before the isolates were cured of their plasmid, 39% of the P. aeruginosa strains were found to be resistant to Ciprofloxacin (CPX), 47%, Ofloxacin (OFX), 44% Pefloxacin (PEF) and 56% Sparfloxacin (SPX). After plasmid curing, the new antibiogram of the isolates showed that some clinical isolates that hitherto were resistant to a given Fluoroquinolone became susceptible, 36% to CPX, 12% to OFX, 12.5% to PEF and 15% to SPX. Agarose gel electrophoresis carried out on the Plasmid DNA revealed that there was detectable Plasmid DNA in 13.9% of the clinical isolates analyzed. Conclusion: There is an alarming increase of clinical infections caused by multidrug resistant strains of P. aeruginosa.13.9% of the multidrug resistance strains of P. aeruginosa in Benin City were Plasmid mediated. Treatment should be based on current Laboratory Susceptibility Test results of the isolates.展开更多
AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from Nove...AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.展开更多
The PM3 and B3LYP methods were employed to calculate the properties of 18 7-substituted fluoroquinolones. The correlation between biological activity （against gram-positive organisms or gram-negative organisms） and ...The PM3 and B3LYP methods were employed to calculate the properties of 18 7-substituted fluoroquinolones. The correlation between biological activity （against gram-positive organisms or gram-negative organisms） and structural properties was obtained by using multiple linear regression （MLR） methods： The best model generated correlates the antibacterial activity with EHOMO and QF8 for gram-positive organisms, and EHOMO and dipole moment for gram-negative organisms, respectively. It suggests that the interaction mechanisms ,of fluoroquinolons with gram-positive and gram-negative organisms are different.展开更多
Ciprofloxacin（CIP）, moxifoxacin（MOX） and enrofloxacin（ENR） were selected as typical fluoroquinolones（FQs） to analyze the excitation-enhancing effect and mechanism of solvents on FQs＇ electron transition based...Ciprofloxacin（CIP）, moxifoxacin（MOX） and enrofloxacin（ENR） were selected as typical fluoroquinolones（FQs） to analyze the excitation-enhancing effect and mechanism of solvents on FQs＇ electron transition based on quantum chemical calculations. The UV spectra of three FQs in gas and five different solvents（water, cyclohexane, dimethylsulfoxide, methanol, acetone） were calculated using Gaussian 09 software. The transition mechanisms of FQs＇ main electron transitions were analyzed by natural bond orbital（NBO） theory, and the solvent effect on each electron transition was assessed qualitatively and quantitatively by sensitivity analysis and an established index system. The excitation enhancing mechanism of solvent on electron transitions of FQs was analyzed from the view of photo-induced reactions between solvent and FQs molecules. The results show that there are two main transitions located in the spectrum ranges of 300~380 and 240~300 nm for each FQ in any medium, which are assigned as n →π＊ and π→π＊ electron transitions, respectively. By comparison, the n →π＊ transition is more sensitive to solvent because of the energy transfer between solvent molecules and FQs, but the solvent effect on the π→π＊ transition is stronger than on the n →π＊ transition. The sequence of affected extent of solvent effect on electron transition was CIP 〉 MOX 〉 ENR, and the sequence of solvent effect was water 〉 DMSO 〉 methanol 〉 acetone 〉 cyclohexane（stronger solvent effect with increasing the dielectric constant of solvent）. From the view of photo-induced reactions, the reaction between FQs＊T1 and solvent＊T1 has the decisive regulatory effect on the n →π＊ transition of FQs in solvent, and the reaction between FQsS0 and solvent＊TI has an enhancing effect on the π→π＊ transition.展开更多
Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones ...Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones and sulfonamides in milk was prepared based on the principle of competitive inhibition immunochromatography. The performance indicators of the test strip were verified. The results showed that the test strip can simultaneously detect 4 tetracyclines,13 fluoroquinolones and 13 sulfonamides,and the detection limits all can meet the national residue limits; the tests strip exhibited false positive rate≤5% and false negative rate = 0; and no cross-reaction with other drugs was commonly found in milk,indicating good specificity. The method is simple,rapid,and has low cost and easy popularization. It provides a means for realizing on-site rapid detection and is of important practical significance to guarantee of safety of milk and dairy products in China.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21976045 and 22076112)China Scholarship Council(CSC)Scholarship(Nos.202208610125 and 202308610123)+1 种基金Shaanxi Key Laboratory of Environmental Monitoring and Forewarning of Trace Pollutants(No.SHJKFJJ202318)the Key Research and Development Program of Shaanxi Province(No.2024SF-YBXM-567).
文摘Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex forms.This study investigated the spectral properties of three fluoroquinolones(FQs)with and without metal ions Fe(III),Cu(II),and Al(III)in solutions under different pH conditions,as well as evaluated the changes in toxicity due to the complex with thesemetal ions using luminescent bacteria(vibrio fischeri).FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions,and the formation of complexes weakened the ultravioletabsorbing ability of FQs.At pH=7.0,Cu(II)quenched the fluorescence intensity of FQs.Moreover,their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored,revealing that the coordination sites of Cu(II)in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom.This conclusion was further verified by the theory of molecular surface electrostatic potential.In addition,except for complexes of ciprofloxacin-metals,enhanced toxicity of FQs upon coordination with Fe(III)was observed,while reduced toxicity was found for coordination with Cu(II)and Al(III).These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions.
基金Financially supported by a grant from the Education Com-mittee of Hunan Province (No.ooAoo9)
文摘Objectives: To determine the susceptibilities of M.hominis and U. urealyticum to fluoroquinolones forthe instruction of reasonable clinical application ofantibiotics.Method: The susceptibilities of M. hominis and U.urealyticum to six fluoroquinolones were determinedby the broth dilution method.Results: Sparfloxacin and gatifloxacin were veryactive with MIC50S of 0.03125 and 0.25 μg/ml againstM. hominis, 0.25 and 0.5 μg/ml against U. urealyticum,respectively. Levofloxacin and ofloxacin had MIC50S of1 μg/ml and 2 μg/ml, respectively against both species.Norfloxacin was less effective against both species at16 and 32 μg/ml. Ciprofloxacin was unusual in thatthe MIC50S varied fourfold between species, with 2 μg/ml against M. hominis and 8 μg/ml against U.urealyticum.Conclusions: The results can provide useful infor-mation for selecting fluoroquinolones for treatmentof urogenital mycoplasma infections.
基金Project supported by the Henan Innovation Project for University Prominent Research Talents(No.2010HASTIT026)the Key Scientific & Technological Project of Education Department in Henan Province of China(No.2011A230003)
文摘Modified 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC)method was employed to synthesize the artificial antigen of norfloxacin(NOR),and New Zealand rabbits were used to produce anti-NOR polyclonal antibody(pAb).Based on the checkerboard titration,an indirect competitive enzyme-linked immunosorbent assay(icELISA) standard curve was established.This assay was sensitive and had a working range from 0.12 to 68.40 ng/ml,with the half maximal inhibitory concentration(IC50)and limit of detection(LOD)values of 2.7 ng/ml and 0.06 ng/ml,respectively.The produced pAb exhibited high cross-reactivity to fluoroquinolones(FQs)tested,and the IC50 values to enoxacin,ciprofloxacin,and pefloxacin were 3.1,3.4,and 4.1 ng/ml,respectively.It also indicated that the concentrations of NaOH and methanol in assay buffer should not be higher than 10%and 30%.When spiked in milk at 5,20,and 50 ng/ml,the recoveries for NOR,enoxacin,ciprofloxacin,and pefloxacin ranged 90.5%-98.0%,84.0%-95.2%,94.0%-106.0%,and 89.5%-100.0%,respectively.The results suggest that this class-specific pAb-based icELISA could be utilized for the primary screening of FQ residues in animal-original products.
基金supported by the Natural Science Foundation of Shaanxi Province (No. 2009jm4002-1)
文摘An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high performance liquid chromatography (HPLC) with diode array detection (DAD) is developed to effectively determine two fiuoroquinolones (enoxacin and lomefioxacin), two sulfonamides (sulfanilamide and sulfamethoxazole) and one tetracycline (tetracycline) simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v). Solvent acetonitrile and solvent acetic acid (0.1%) were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a fiow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 mg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs) (below 6.1%, nfi3) and the limits of quantitation (LOQ) ranged from 7 mg/kg to 34 mg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described.
基金supported by the National Natural Science Foundation of China(Nos20872028 and 21072045)
文摘To further explore an efficient modified route for the shift from an antibacterial fluoroquinolone to an antitumor one,mono-Schiff bases 6a-6h related to ciprofloxacin C3 carbonylhydrazone and bis-Schiff bases 4a-4h corresponding to C3/C7 carbonylhydrazone/hydrazone attached on a skeleton of ciprofloquinolone were designed and synthesized,and their in vitro antitumor activity against CHO,HL60,L1210 cells and antibacterial activity against Staphylococcus aureus and Escherichia coli were also reported.
基金“Plan Nacional de I+D+I”Instituto de Salud Carlos III(Fondo de Investigaciones Sanitarias [FIS] PI14/00174)+1 种基金ubdirección General de Redes y Centros de Investigación Cooperativa,Spanish Ministry of Science,Innovation and Universities,Spanish Network for Research in Infectious Diseases(REIPI RD16/0016)cofinanced by the European Development Regional Fund(EDRF)"A way to achieve Europe"
文摘Solid organ transplantation(SOT)is the best treatment option for end-stage organ disease.Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection,particularly due to the reactivation of latent infections due to opportunistic agents such as Mycobacterium tuberculosis.Active tuberculosis(TB)after SOT is a significant cause of morbidity and mortality.Most cases of posttransplant TB are secondary to reactivation of latent tuberculosis infection(LTBI)due to the effects of long-term immunosuppressive therapy.Risk minimization strategies have been developed to diagnose LTBI and initiate treatment prior to transplantation.Isoniazid with vitamin B6 supplementation is the treatment of choice.However,liver transplantation(LT)candidates and recipients have an increased risk of isoniazid-induced liver toxicity,leading to lower treatment completion rates than in other SOT populations.Fluoroquinolones(FQs)exhibit good in vitro antimycobacterial activity and a lower risk of drug-induced liver injury than isoniazid.In the present review,we highlight the disease burden posed by posttransplant TB and summarize the emerging clinical evidence supporting the use of FQs for the treatment of LTBI in LT recipients and candidates.
基金Supported by the National Natural Science Foundation of China(Nos.20872028,21072045)
文摘To discover an efficient route for the shift from an antibacterial fluoroquinolone to an antitumor one based on the mechanistic similarities between targeting topoisomerases and the eukaryotic ones,two series of the title compounds,C3 bis-oxadiazole methylsulfides 6a―6h and corresponding dimethylpiperazinium iodides 7a―7h derived from levofloxacin 1 were designed and synthesized.Their in vitro antiproliferative activities against Chinese hamster ovary cell line（CHO）,murine leukemia cell line（L1210） and human leukocytoma cell line（HL60） were evaluated by MTT assay,and inhibitory effect on DNA topoisomerase IIα was also measured by means of densitometric assay.
文摘Helicobacter pylori (H. pylori) is a widespread pathogen infecting about 40% of people living in urban areas and over 90% of people living in the developing regions of the world. H. pylori is well-documented as the main factor in the pathogenesis of peptic ulcer disease, chronic gastritis, and gastric malignancies such as cancer and mucosa-associated lymphoid tissue-lymphoma; hence, its eradication is strongly recommended. The Maastricht IV consensus, which focused on the management of H. pylori infection, set important new strategies in terms of treatment approaches, particularly with regards to first- and second-line treatment protocols and led to improved knowledge and understanding of H. pylori resistance to antibiotics. In recent years, various fluoroquinolone-based protocols, mainly including levofloxacin, have been proposed and effectively tested at all therapeutic lines for H. pylori eradication. The aim of the present paper is to review the scientific literature focused on the use of fluoroquinolones in eradicating H. pylori.
基金financially supported by the National Natural Science Foundation(Nos.21590814,51525806)
文摘The detailed sorption steps and biodegradation characteristics of fluoroquinolones （FQs） including ciprofloxacin, enrofloxacin, lomefloxacin, norfloxacin, and ofioxacin were investigated through batch experiments. The results indicate that FQs at a total concentration of 500 μg/L caused little inhibition of sludge bioactivity. Sorption was the primary removal pathway of FQs in the activated sludge process, followed by biodegradation, while hydrolysis and volatilization were negligible. FQ sorption on activated sludge was a reversible process governed by surface reaction, Henry and Freundlich models could describe the FQ sorption isotherms well in the concentration range of 100-300 μg/L. Thermodynamic parameters revealed that FQ sorption on activated sludge is spontaneous, exothermic, and enthalpy-driven. Hydrophobicity-independent mechanisms determined the FQ sorption affinity with activated sludge. The zwitterion of FQs had the strongest sorption affinity, followed by cation and anion, and aerobic condition facilitated FQ sorption. PQs were slowly biodegradable, with long half-lives （〉100 hr）. FQ biodegradation was enhanced with increasing temperature and under aerobic condition, and thus was possibly achieved through co-metabolism during nitrification. This study provides an insight into the removal kinetics and mechanism of FQs in the activated sludge process, but also helps assess the environmental risks of FQs resulting from sludge disposal.
文摘In order to study the resistance of Neisseria （N.） gonorrhoeae to the fluoroquinolone and detect mutation patterns of quinolone resistance-determining regions （QRDRs） of clinical isolates in Shanghai, China, a total of 80 clinical isolates of N. gonorrhoeae were consecutively collected from Shanghai. The MIC of fluoroquinolone for the isolates was examined by using the agar dilution method and the mutation profiles of the QRDRs of gyrA and parC were analyzed by sequencing and restriction fragment length polymorphism （RFLP）. Chi-square test was used for comparison of the t：nutation patterns. The results showed that： （1） High percentages of the 8 isolates were resistant to ciprofloxacin （95.0%）, ofloxacin （95.0%） and lomefloxacin （97.5%）, only one strain was susceptible to the ciprofloxacin. （2） Sensitive strains had a substitute of Asp95→Ala in the gyrA, and all isolates that were resistant or intermediated to the ciprofloxacin, had a double mutation in the gyrA （Ser91, Ala 92 and Asp95）. Some strains also had a mutation in the parC. （3） The MICs of these isolates were significantly associated with the mutation patterns in the gyrA and parC. A double mutation of gyrA combined with parC87 mutation was a predominant pattern in Shanghai and could mediate high level resistance to ciprofloxacin. It suggests that mutations in the QRDRs of gyrA and parC may be responsible for the fluoroquinolone resistance. And fluoroquinolone could not be used as the first line antibiotics for gonorrhea treatment any more in Shanghai, China.
基金financially supported by the National Key Research and Development Plans of Special Project for Site Soil(No.2018YFC1802003)the National Science Foundation of China(Nos.21906079,21777066 and 41703090)the Natural Science Foundation of Jiangsu Province of China(No.BK20170634)。
文摘Over the recent past,fluoroquinolone antibiotics(FQs)have raised extensive attention due to their potential to induce the formation of resistance genes and"superbugs",thus various advanced oxidation techniques have been developed to eliminate their release into the environment.In the present study,the prototype tetraamido macrocyclic ligand(Fe^Ⅲ-TAML)/hydrogen peroxide(H2O_(2))system is employed to degrade FQs(i.e.,norfloxacin and ciprofloxacin)over a wide p H range(i.e.,p H 6-10),and the reaction rate increases with the increase in p H level.The effect of dosage of Fe^Ⅲ-TAML and H2O_(2) on the degradation of FQs is evaluated,and the reaction rate is linearly correlated with the added amount of chemicals.Moreover,the impact of natural organic matters(NOM)on the removal of FQs is investigated,and the degradation kinetics show that both NOM type and experimental concentration exhibit negligible influence on the oxidative degradation of selected antibiotics.Based on the results of liquid chromatography-high resolution mass spectrometry and theoretical calculations,the reaction sites and pathways of FQs by Fe^Ⅲ-TAML/H2O_(2) system are further predicted and elucidated.
文摘AIMTo compare the conjunctival epithelial toxicities of three newer-generation fluoroquinolones without preservatives.METHODSIn a prospective, randomized, double blind comparative study, 47 eyes of 47 patients with a primary pterygium were enrolled, and divided randomly into three groups (levofloxacin 0.5%, gatifloxacin 0.3%, and moxifloxacin 0.5%). After pterygium surgery with the same conjunctival autograft technique, each patient maintained a regimen with a randomly assigned fluoroquinolone eye drop. Patients were examined every other day after surgery until the epithelium had completely healed. Photos were taken and used to measure the area of residual epithelial defects. Conjunctival healing time and speed (initial defect area/healing time (mm<sup>2</sup>/d) compared in each group using Kruskal-Wallis tests.RESULTSThere were no significant differences in mean age, gender, and conjunctival defect size of the donor site between these groups. However, the mean of conjunctival healing time and speed were statistically different in each group. The mean of conjunctival epithelial healing time was 8.93±2.69d (levofloxacin group), 10.31±2.96d (gatifloxacin group), and 13.50±4.10d (moxifloxacin group), P=0.006. The mean conjuctival epithelial healing speed was 6.18±1.39 mm<sup>2</sup>/d (levofloxacin group), 5.52±1.68 mm<sup>2</sup>/d (gatifloxacin group), and 4.40±1.30 mm<sup>2</sup>/d (moxifloxacin group), P=0. 003.CONCLUSIONWithout the influence of preservatives, levofloxacin and gatifloxacin might be less toxic to the regeneration of conjunctival epithelial cells and cause a faster conjunctival wound healing relative to moxifloxacin.
文摘Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed primers to amplify the Quinolone-resistance-determining region （QRDR） of gyrA and par（？,, then the PCR products were sequenced and analyzed. In comparision with NCTC5776, a single mutation was found at base 371 in gyrA of strain 38 which changed from C to T, and a single mutation was found at base 350 in gyrA of strain 60 which changed from A to C. No mutation was found in gyrA of the rest The mutation of strain 38 led to an amino acid substitution of Arg99Cys and the mutation of 60 led to an amino acid substitution of Met 92 Leu. No mutation was found in parC QRDR of all the isolates. These results indicats that the DNA gyrase will be the primary target to salmonella of fluoroquinolone.
基金supported by the National Key R&D Program of China(No.2017YFB0202600)the National Natural Science Foundation of China(Nos.21672064,21702061,81861138047)+3 种基金the Innovative Research Team of High-level Local Universities in Shanghaithe National Special Fund for State Key Laboratory of Bioreactor Engineering(No.2060204)"Shu Guang"project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(No.14SG28)the Shanghai Sailing Program(No.17YF1403600)。
文摘Polymyxin B(PB),as the last-line of defense against multidrug-resistant Gram-negative bacteria,has caused resistance to P.aeruginosa recently.Fortunately,synergistic treatment could preserve the last class of antibiotics and reduce the emergency of drug resistance.Here,we performed a screen of 970 approved drugs synergized with PB against the P.aeruginosa DK2,which is severely resistant to PB,MIC=512μg/mL.Encouragingly,we found fluoroquinolones could synergy with PB and achieved an obvious reduction in MIC of PB below the clinical susceptible breakpoint(2 μg/mL).Especially,gemifloxacin achieved the highest synergistic effect with PB,leading to a 4096-fold MIC reduction(reduced from512 μg/mL to 0.125 μg/mL).Furthermore,synergistic effect was also observed in the combination of gemifloxacin and colistin.Finally,outer membrane permeabilization assay showed that gemifloxacin could increase the permeability of bacterial cell membranes for P.aeruginosa which partly explained the synergy mechanism.These results indicate that fluoroquinolones represent attractive synergists to address the emerging threat of polymyxin-resistant infections.
基金supported by National Natural Science Foundation of China(Nos.20872028,21072045)
文摘To further expand an effective modified route for the shift from an antibacterial fluoroquinolone （FQ） to an antitumor FQ, two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings, [ 1,2,4]triazolo[3,4- b][1,3,4]thiadiazine and pyrazolo[5,1-c][1,2,4]triazole, respectively, were designed and synthesized starting from the current antibacterial FQs, and their in vitro antitumor activity against L1210, CHO cell lines were evaluated via their respective IC50 values.
文摘Aim: To determine the Plasmid DNA profile of the multidrug resistant strains of Pseudomonas aeruginosa in the clinical isolates. Materials and Methods: Of the 150 clinical samples (Ear swab, Urine, Wound swab, Sputa and Semen) received at Lahor Research Laboratory and Medical center in Benin City, between January 2010 and December 2012, 36 (24%) yielded significant growth of P. aeruginosa. Samples were cultured on MacConkey and Blood agar. Clinical isolates were identified using standard method. Antibiotics susceptibility test employing agar disc diffusion method was used. Clinical isolates were subjected to Plasmid DNA profiling and curing test was carried out at Lahor Molecular Laboratory. This was followed by a post plasmid curing susceptibility test. Agarose gel electrophoresis was carried out to separate the Plasmid DNA using standard method. Bands were visualized using UV illuminator. Results: Wound swabs had the highest numbers of clinical isolates of P. aeruginosa (55.6%) followed by Urine, Semen, Sputa and Ear swab (19.4%, 11.0%, 8.3%, and 5.6%) respectively. Before the isolates were cured of their plasmid, 39% of the P. aeruginosa strains were found to be resistant to Ciprofloxacin (CPX), 47%, Ofloxacin (OFX), 44% Pefloxacin (PEF) and 56% Sparfloxacin (SPX). After plasmid curing, the new antibiogram of the isolates showed that some clinical isolates that hitherto were resistant to a given Fluoroquinolone became susceptible, 36% to CPX, 12% to OFX, 12.5% to PEF and 15% to SPX. Agarose gel electrophoresis carried out on the Plasmid DNA revealed that there was detectable Plasmid DNA in 13.9% of the clinical isolates analyzed. Conclusion: There is an alarming increase of clinical infections caused by multidrug resistant strains of P. aeruginosa.13.9% of the multidrug resistance strains of P. aeruginosa in Benin City were Plasmid mediated. Treatment should be based on current Laboratory Susceptibility Test results of the isolates.
基金Supported by Pró-Reitoria de Pesquisa da Universidade Federal de Minas Gerais,Fundacao de AmparoàPesquisa do Estado de Minas Gerais(FAPEMIG)and Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),Brazil
文摘AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.
基金This work was supported by NNSFC (20563005) and partially supported by Center for Advanced Studies of Medicinal and Organic Chemistry of Yunnan University
文摘The PM3 and B3LYP methods were employed to calculate the properties of 18 7-substituted fluoroquinolones. The correlation between biological activity （against gram-positive organisms or gram-negative organisms） and structural properties was obtained by using multiple linear regression （MLR） methods： The best model generated correlates the antibacterial activity with EHOMO and QF8 for gram-positive organisms, and EHOMO and dipole moment for gram-negative organisms, respectively. It suggests that the interaction mechanisms ,of fluoroquinolons with gram-positive and gram-negative organisms are different.
文摘Ciprofloxacin（CIP）, moxifoxacin（MOX） and enrofloxacin（ENR） were selected as typical fluoroquinolones（FQs） to analyze the excitation-enhancing effect and mechanism of solvents on FQs＇ electron transition based on quantum chemical calculations. The UV spectra of three FQs in gas and five different solvents（water, cyclohexane, dimethylsulfoxide, methanol, acetone） were calculated using Gaussian 09 software. The transition mechanisms of FQs＇ main electron transitions were analyzed by natural bond orbital（NBO） theory, and the solvent effect on each electron transition was assessed qualitatively and quantitatively by sensitivity analysis and an established index system. The excitation enhancing mechanism of solvent on electron transitions of FQs was analyzed from the view of photo-induced reactions between solvent and FQs molecules. The results show that there are two main transitions located in the spectrum ranges of 300~380 and 240~300 nm for each FQ in any medium, which are assigned as n →π＊ and π→π＊ electron transitions, respectively. By comparison, the n →π＊ transition is more sensitive to solvent because of the energy transfer between solvent molecules and FQs, but the solvent effect on the π→π＊ transition is stronger than on the n →π＊ transition. The sequence of affected extent of solvent effect on electron transition was CIP 〉 MOX 〉 ENR, and the sequence of solvent effect was water 〉 DMSO 〉 methanol 〉 acetone 〉 cyclohexane（stronger solvent effect with increasing the dielectric constant of solvent）. From the view of photo-induced reactions, the reaction between FQs＊T1 and solvent＊T1 has the decisive regulatory effect on the n →π＊ transition of FQs in solvent, and the reaction between FQsS0 and solvent＊TI has an enhancing effect on the π→π＊ transition.
基金Supported by Hebei Science and Technology Program(16275507D)
文摘Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones and sulfonamides in milk was prepared based on the principle of competitive inhibition immunochromatography. The performance indicators of the test strip were verified. The results showed that the test strip can simultaneously detect 4 tetracyclines,13 fluoroquinolones and 13 sulfonamides,and the detection limits all can meet the national residue limits; the tests strip exhibited false positive rate≤5% and false negative rate = 0; and no cross-reaction with other drugs was commonly found in milk,indicating good specificity. The method is simple,rapid,and has low cost and easy popularization. It provides a means for realizing on-site rapid detection and is of important practical significance to guarantee of safety of milk and dairy products in China.
