Study on the Interaction Between Nucleic Acids and Acetamiprid

Abstract

The interaction between deoxyribonucleic acid (DNA) and acetamiprid was studied. It was found that the fluorescence of acetamiprid could be enhanced in the presence of DNA in sulfuric acid solution. The excitation and emission wavelength of acetamiprid was 291 nm and 587 nm, respectively. Under optimal conditions, the calibration graph is over the range of 0.1–10 µg mL^?1. The calibration limit is 0.06 µg mL^?1 (S/N = 3). The determination results of DNA in yeast cell and golden staphylococcus samples by this method were satisfactory. The mechanism of the reaction is discussed.     

The determination of deoxyribonucleic acids with triadimenol based on the enhancement of resonance light scattering

For the first time, triadimenol was used to determine nucleic acid (DNA) using the resonance light scattering (RLS) technique. The RLS of triadimenol was greatly enhanced by DNA in the range of pH 1.6 to approximately 1.9. A resonance light-scattering peak at 310 nm was found, and the enhanced intensity of RLS at this wavelength was proportional to the concentration of DNA. The linear range of the calibration curve was 0 to approximately 9 microg/ml with the detection limit of 24 ng ml(-1). The mechanism studies of the system indicated that the enhanced RLS is due to the aggregation of triadimenol on DNA. The nucleic acids in synthetic samples and in rice seedling extraction were analyzed with satisfactory results. Compared with other methods, this method is convenient, rapid, inexpensive and simple.     

Turbidimetric method for quantitative determination of triton X-100 with silicotungstic acid

The Formation of Triton X-100-silicotungstic acid complex was studied. Quantitative turbidimetric determination of the detergent based on this process was suggested. This method allows to determining the complex formation at any wavelength in the range from 350 (epsilon 350 = 15,600 cm-1 M-1) to 600 nm (epsilon 600 = = 9090 cm-1 M-1). The calibration curve for Triton X-100 recorded at 350 nm is linear in the concentration range of 0 to 30 micrograms/ml. A sigmoid calibration curve was observed at longer wavelengths. A linear fragment of the calibration curve recorded at 600 nm was found at a concentration of Triton X-100 of about 5 micrograms/ml. The complex nature of calibration curves can be explained by heterogeneity of the complex dispersion.     

梯度洗脱高效液相色谱法测定桑叶中3种活性成分的含量

建立同时测定桑叶中绿原酸、芦丁和槲皮素含量的分析方法。色谱柱为NUCLEODUR C18 RP(250 mm×4.6 mm,5μm),光电二极管检测器,流动相为甲醇-质量分数0.5%磷酸水溶液,梯度洗脱程序为0 min(30:70)-15min(30:70)-25min(50:50)-35min(85:15)-40min(30:70);流速0.8 ml.min-1,检测波长为350 nm。绿原酸、芦丁和槲皮素的线性范围分别为0.1144~1.0296μg(r=0.9996)、0.0436~0.3924μg(r=0.9999)和0.0452~0.4068μg(r=0.9997),平均回收率分别为97.7%(RSD=1.7%)、98.4%(RSD=2.2%)和100.6%(RSD=1.5%)。方法快速简便,专属性强,重复性好,可作为桑叶中绿原酸、芦丁和槲皮素的定量分析方法。     

高效液相色谱-光电二极管检测器法测定栀子中乌索酸的研究

建立反相高效液相色谱法测定了栀子中乌索酸的质量分数,同时采用光电二极管阵列检测器检测乌索酸色谱峰的纯度。色谱柱为Nuc leosil C18柱(4.6 mm×250 mm,5μm),流动相为甲醇-水(85∶15,V/V),流速0.8 mL.m in-1,检测波长205 nm,柱温25℃。乌索酸在0.1696~1.5264μg范围内线性关系良好(r=0.9999),检出限为0.3 mL-1(3σ),平均回收率为98.0%。方法简便,准确,重现性好,线性范围宽,适于测定栀子药材中乌索酸的质量分数。     

杀虫剂啶虫脒和毒死蜱对捕食蜘蛛血细胞DNA的损伤作用

应用蜘蛛血细胞微核试验和单细胞凝胶电泳试验研究了两种杀虫剂啶虫脒和毒死蜱对蜘蛛头胸部和腹部血细胞DNA的损伤作用。结果表明：在啶虫脒和毒死蜱各供试浓度作用下,对蜘蛛血细胞微核率有明显的影响,与对照组相比有显著性差异(p<0.05,p<0.01);且随着两种农药浓度升高,血细胞微核率显著增加,存在明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞微核率相关系数r=0.9284,腹部为r=0.9071;毒死蜱与星豹蛛头胸部血细胞微核率相关系数r=0.9841,腹部为r=0.9793);啶虫脒和毒死蜱对星豹蛛血细胞DNA损伤有明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9838,腹部为r=0.9834;毒死蜱与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9807,腹部为r=0.9659);且两种农药在同种农药同一浓度作用下,对星豹蛛腹部血细胞微核率和DNA损伤程度要明显大于头胸部。     

比色法测定复方氨基酸注射液中亚硫酸盐的含量

目的:采用比色法测定复方氨基酸注射液中亚硫酸盐的含量。方法:以碱性品红·甲醛溶液为显色剂,检测波长为576nm。结果:二氧化硫在0.4～2mg·L-1质量浓度范围内呈良好的线性关系,回归方程为:A=0.3041C-0.0505,(r=0.9923,n=5);平均回收率为99.9%(RSD=1.19%,n=9)。结论:按此方法检测方便快速,结果准确可靠,能满足对产品中亚硫酸盐含量控制的要求。     

Determination of scutellarin in mouse plasma and different tissues by high-performance liquid chromatography

A simple HPLC-UV method was developed for the determination of scutellarin in plasma and different tissues of mice (heart, liver, spleen, lungs and kidneys). The separation was achieved by HPLC on a Hypersil C(18) column with a mobile phase composed of methanol-water-glacial acetic acid (40:60:1). UV detection was used at 335 nm. The calibration curves were linear in all matrices (r(2)>0.997) in the concentration range of 0.1-10 microg/ml for plasma and 0.1-20 microg/g for tissue homogenates, respectively. The method described is suitable for studies on the distribution of scutellarin in different tissues of mice.     

Isolation and characterization of Caulobacter crecentus bacteriophage phi Cd1.

A DNA-containing bacteriophage, phiCd1, was isolated from sewage and shown to infect both stalked and swarmer cells of Caulobacter crescentus strain CB13B1a. phiCd1 is a small, icosohedral bacteriophage, 60 nm in diameter, which possesses a short, noncontractile tail, 10 to 12 nm in length. The bacteriophage particle is composed of at least eight structural proteins. phiCd1 nucleic acid exists as a linear duplex of DNA as judged by: (i) thermal denaturation (Tm), (ii) CsCl density gradient centrifugation, and (iii) chemical analysis of its base composition. The DNA is 61% guanosine plus cytosine, has a buoyant density in CsCl of 1.721 +/- 0.001 g/cm3, and denatures sharply at 78.5 C in 0.1 SSC (standard saline citrate) buffer. The S20, w value for the DNA is 34.3 +/- 0.1S as compared with T7 DNA, indicating a molecular weight of about 29 x 10(6).     

Determination of telithromycin in human plasma and microdialysates by high-performance liquid chromatography

A high-performance liquid chromatography method for the quantitative determination of telithromycin in biological fluids is described. The method is suitable for plasma and microdialysates from the interstitial space fluid of skeletal muscle and subcutaneous adipose tissue. Plasma samples were deproteinised with trichloroacetic acid and neutralised with sodium hydroxide. Microdialysates were analysed without further preparation step. Telithromycin was separated isocratically on a reverse-phase column using acetonitrile-0.03 M ammonium acetate, pH 5.2 (43:57, v/v) at a flow rate of 0.8 mlmin(-1), and fluorescence detection (excitation 263 nm, emission 460 nm). The calibration curve was linear from 0.01 to 5 microgml(-1). Within- and between-day imprecision and inaccuracy was < or =10%. The limits of quantification were 0.02 and 0.015 microgml(-1) for plasma and microdialysates, respectively. Since telithromycin is decomposed in aqueous solution at ambient temperature, it is strongly recommended to store samples frozen at -80 degrees C, to maintain the temperature at 4 degrees C during all preparation steps, and to analyse samples within 120 min after thawing.     

Circular dichroism as a probe of DNA structure inside reconstituted nucleohistones.

Reconstituted nucleohistones were obtained by mixing in given conditions acid extracted histones and eukaryotic DNA. The histone/DNA ratio (w/w) was in the range 0.35 - 0.95. With the four histones (H2A2B) we have been able to obtain subunits (nucleosomes or upsilon-bodies). The variation of cirsular dichroism signal with temperature at 280 nm was measured to follow structural changes of the DNA inside the complex. The true change of ellipticity (see article) of histone-bound DNA regions, is similar for reconstituted nucleohistone and H1-depleted chromatin, and is therefore a physical probe of the presence of nucleosomes.     

The Determination of Deoxyribonucleic Acids with Triadimenol Based on the Enhancement of Resonance Light Scattering

For the first time, triadimenol was used to determine nucleic acid (DNA) using the resonance light scattering (RLS) technique. The RLS of triadimenol was greatly enhanced by DNA in the range of pH 1.6 ～ 1.9. A resonance light‐scattering peak at 310nm was found, and the enhanced intensity of RLS at this wavelength was proportional to the concentration of DNA. The linear range of the calibration curve was 0 ～ 9 µg/ml with the detection limit of 24 ng ml^? 1. The mechanism studies of the system indicated that the enhanced RLS is due to the aggregation of triadimenol on DNA. The nucleic acids in synthetic samples and in rice seedling extraction were analyzed with satisfactory results. Compared with other methods, this method is convenient, rapid, inexpensive and simple.     

Analysis of the amino acid indospicine in biological samples by high performance liquid chromatography

Indospicine is a hepatotoxic amino acid that accumulates in the meat of horses that consume the legume Indigofera linnaei. A method to determine indospicine concentration in biological samples using an amino acid analyser has been reported, but the analysis time is long and therefore not suited to the analysis of large numbers of samples. A rapid and reliable method was developed for the analysis of indospicine in horsemeat and serum using High Performance Liquid Chromatography. Horsemeat and serum were extracted with either water or 0.01 N hydrochloric acid, respectively, and deproteinized by ultrafiltration. Precolumn derivatization of samples with phenylisothiocyanate was followed by separation of indospicine from other amino acids on a Pico-Tag C 18 column and UV detection at 254 nm. The calibration curves for indospicine in horsemeat extract were linear over the concentration range 0.4 microg ml(-1) to 20 microg ml(-1), while for indospicine in serum, the linear range was from 0.17 microg ml(-1) to 16.67 microg ml(-1). The mean recovery of indospicine in horsemeat extract was 87.2 +/- 6.8% and in serum was 97.3 +/- 9.9%. Analysis time for indospicine in horsemeat samples was 31 min and in serum samples was 36 min.     

Determination of gabapentin in human plasma by capillary electrophoresis with laser-induced fluorescence detection and acetonitrile stacking technique

A sensitive analytical method for gabapentin [1-(aminomethyl) cyclohexaneacetic acid] (GBP) in human plasma based on capillary electrophoretic separation and laser-induced fluorescence (LIF) detection has been developed. 6-Carboxyfluorescein succinimidyl ester (CFSE) was used for precolumn derivatization of the non-fluorescent drug in plasma. Optimal separation and detection were obtained with an electrophoretic buffer of 50mM sodium borate (pH 9.5) and an air-cooled argon-ion laser (excitation at 488 nm, emission at 520 nm). A calibration curve ranging from 0.3 to 150 microM was shown to be linear. The concentration limit of detection (LOD) in plasma was 60 nM. We also demonstrate how the detection limit can be enhanced by using acetonitrile stacking technique. With stacking, the limit of detection for gabapentin in plasma was 4.8 nM. A calibration curve ranging from 0.03 to 15 microM was shown to be linear. Both the within-day and day-to-day reproducibility and accuracy were 相似文献   

Photochemical covalent binding of urocanic acid to polynucleic acids

Photolysis of E-[ring-2-14C]urocanic acid (UA) with native or denatured calf thymus DNA leads to covalent binding of the radiolabel to the nucleic acid. A similar observation is made upon photolysis of the labeled UA with the polyribonucleotides, in which case a strong preference is observed for binding to poly[U]. DNA or poly[U], which had been reacted with UA and purified by dialysis and multiple precipitations, releases UA upon further irradiation with 254 nm light (as expected for cyclobutane adducts). Quantum efficiencies for binding of the UA to native DNA have been measured at 308 and 266 nm and are 0.30 x 10(-5) and 1.3 x 10(-4), respectively, at comparable reactant concentrations. The large increase at the shorter wavelength (where DNA absorption is more competitive) is taken as evidence for the primary role of a DNA excited state in initiating the binding reaction(s).     

Quantifying crystal form content in physical mixtures of (±)-tartaric acid and (+)-tartaric acid using near infrared reflectance spectroscopy

The objective of this study was to use diffuse reflectance near infrared spectroscopy (NIRS) to determine racemic compound content in physical mixtures composed primarily of the enantiomorph and to assess the error, instrument reproducibility and limits of detection (LOD) and quantification (LOQ) of the method. Physical mixtures ranging from 0 to 25% (±)-tartaric acid in (+)-tartaric acid were prepared and spectra of the powder samples contained in glass vials were obtained using a Foss NIRSystems Model 5000 monochrometer equipped with a Rapid Content Analyzer scanning from 1100 to 2500 nm. A calibration curve was constructed by plotting (±)-tartaric acid weight percent against the 2^nd derivative values of log (1/R) vs λ at a single wavelength, normalized with a denominator wavelength (1480 nm/1280 nm). Excellent linearity was observed (R²=0.9999). The standard error of calibration (SEC) was 0.07 and the standard error of prediction (SEP) for the validation set was 0.11. Instrument and method errors for samples in the 2% composition range ((±)-tartaric acid in (+)-tartaric acid) were less than 1% RSD and 3% RSD, respectively. The practical LOD and LOQ were 0.1% and 0.5%, respectively, and comparable to the calculated LOD and LOQ. These studies show that NIRS can be used as a rapid and sensitive quantitative method for determining racemate content in the presence of the enatiomerically pure crystal in the solid-state. Published: October 6, 2005     

Simultaneous direct determination of amiloride and triamterene in urine using isopotential fluorometry

A method for the simultaneous fluorometric determination of two diuretics in urine is proposed. The combination of matrix isopotential synchronous fluorescence (MISF) and first derivative techniques provides good analytical results. MISF spectra are obtained by calculating the isopotential trajectory in the three-dimensional fluorescence spectrum for a urine solution. In the spectral contour, the trajectory is taken to be the portion of the line that passes by the fluorescence maxima of both diuretics (lambda(ex) = 365 and lambda(em) = 413 nm for amiloride and lambda(ex) = 365 and lambda(em) = 437 nm for triamterene). Because contour lines connect points of identical intensity and the trajectory is part of a contour line, it is called "isopotential." Analyses was carried out in a 1/1 (v/v) ethanol/water mixture, using an apparent pH of 6.3 provided by 0.01 M sodium/citrate citric acid buffer. Urine samples are diluted 50 times and provide linear calibration plots at amiloride and triamterene concentrations up to 320 and 100 ng mL(-1), respectively. The goodness of the analytical signal was checked by using variance analysis. Signals recorded throughout the calibration range were subjected to three calibrations per each analyte, both in the absence and in the presence of variable amounts of the other analyte. Differences between individual calibrations and slopes were compared with those within individual calibrations. Based on the results, triamterene and amiloride can be accurately quantified in the presence of each other. The limit of detection calculated according to Clayton who uses error propagation throughout the calibration curve and a noncentralized security factor was 16.8 and 2.4 ng mL(-1) for amiloride and triamterene, respectively.     

Determination of three bile acids in artificial Calculus Bovis and its medicinal preparations by micellar electrokinetic capillary electrophoresis

A micellar electrokinetic capillary electrophoresis (MEKCE) method for the determination of cholic acid (CA), hyodeoxycholic acid (HDCA) and chenodeoxycholic acid (CDCA) in artificial Calculus Bovis and its four medicinal preparations is described. The buffer solution consisted of 40 mM disodic phosphate and 40 mM sodium dodecylsulfate (SDS) adjusted to pH 9.0. UV detection was set to 200 nm. Under optimum conditions, the analytes were baseline separated within 11min. The linear calibration range was 12.1-970 microgml(-1) for CA and 18.8-950 microgml(-1) for HDCA and CDCA, respectively. It was found that overall recoveries were within the range of 98-102%, and R.S.D.s were less than 5% for the analytes. This method, due to its convenience, high accuracy and good reproducibility can be employed in quality control of artificial Calculus Bovis and its medicinal preparations.     

A homogeneous DNA hybridization system by using a new luminescence terbium chelate

Homogeneous DNA hybridization assay based on the luminescence resonance energy transfer (LRET) from a new luminescence terbium chelate, N,N,N(1),N(1)-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-phenylpyridine]tetrakis(acetic acid) (BPTA)-Tb(3+) (lambda(ex) = 325 nm and lambda(em) = 545 nm) to an organic dye, Cy3 (lambda(ex) = 548 nm and lambda(em) = 565 nm), has been developed. In the system, two DNA probes whose sequences are complementary to the two different consecutive sequences of a target DNA are used; one of the probes is labeled with the Tb(3+) chelate at the 3'-end, and the other is with Cy3 at the 5'-end. Labeling of the Tb(3+) chelate is accomplished via the linkage of a biotin-labeled DNA probe with the Tb(3+) chelate-labeled streptavidin. Strong sensitized emission of Cy3 was observed upon excitation of the Tb(3+) chelate at 325 nm, when the two probe DNAs were hybridized with the target DNA. The sensitivity of the assay was very high compared with those of the previous homogeneous-format assays using the conventional organic dyes; the detection limit of the present assay is about 30 pM of the target DNA strand.