Evaluation of performance and application of three nucleic acid extraction methods for quantification of plasma Epstein-Barr virus DNA / 中华检验医学杂志

Objective To evaluate and compare the analytical performances and application values of three nucleic acid extraction methods for quantification of plasma Epstein-Barr Virus ( EBV ) DNA. Methods It used silica membrane spin column , boiling and automated magnetic bead method to extract viral nucleic acid in parallel , and combined real-time fluorescence quantitative PCR assays for quantitative EBV-DNA quantification.The performances of three methods were determined and compared by using the third-party reference materials , and the clinical values were analyzed by pairing detecting 100 NPC patients and 100 healthy subjects in pair .Results The accuracy and imprecision of three methods were all in line with requirements , and the results of clinical samples were linearly correlated . But actually the reproducibility and intermediate imprecision of the magnetic bead method were smaller and stable than those of the spin column method and the boiling method ( all <3％);the limit of detection for the magnetic bead method was 3.334 ×101 IU/ml, better than that of spin column method (4.159 ×101 IU/ml) and boiling method (8.511 ×101 IU/ml);the linear range of the magnetic bead method was 5.4 ×101 -5.4 ×105 IU/ml, slightly wider than that of the boiling method (5.4 ×102 -5.4 ×105 IU/ml); the ability of anti -Hb interference ability of magnetic bead method is better than that of boiling method ;and the positive rate and the mean viral load of the NPC samples measured with the magnetic bead method were significantly higher (95％, 8.342 ×103 IU/ml) than those measured with the spin column method (84％, 4.707 ×103 IU/ml) and the boiling method (78％, 2.571 ×103 IU/ml) ( P all<0.05).Conclusion The automated magnetic bead nucleic acid extraction method offered better analytical performance and higher clinical value for EBV DNA quantification in plasma .

Synthesis, DNA cleavage and antimicrobial activity of 4-thiazolidinones-benzothiazole conjugates.

Antimicrobial screening of several novel 4-thiazolidinones with benzothiazole moiety has been performed. These compounds were evaluated for antimicrobial activity against a panel of bacterial and fungal strains. The strains were treated with these benzothiazole derivatives at varying concentrations, and MIC’s were calculated. Structures of these compounds have been determined by spectroscopic studies viz., FT-IR, 1H NMR, 13C NMR and elemental analysis. Significant antimicrobial activity was observed for some members of the series, and compounds viz. 3-(4-(benzo[d]thiazol-2-yl) phenyl)-2-(4-methoxyphenyl)thiazolidin-4-one and 3-(4-(benzo[d]thiazol-2-yl)phenyl)-2-(4-hydroxy phenyl)thiazolidin-4-one were found to be the most active against E.coli and C.albicans with MIC values in the range of 15.6–125 μg/ml. Preliminary study of the structure–activity relationship revealed that electron donating groups associated with thiazolidine bearing benzothiazole rings had a great effect on the antimicrobial activity of these compounds and contributes positively for the action. DNA cleavage experiments gave valuable hints with supporting evidence for describing the mechanism of action and hence showed a good correlation between their calculated MIC’s and its lethality.

Synthesis, characterization, antimicrobial and DNA cleavage studies of transition metal complexes of 4-(trifluoro-4-ylidene) hydrazine carbothioamide.

New complexes of Co(II), Ni(II), Cu(II), Cd (II), Pt(II),and Pd(II) with 4-(trifluoro-4-ylidene) hydrazine carbothioamide have been synthesized. All the new compounds were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, LC-MS. H1NMR, FTIR and electronic spectral studies. Based on the molar conductance measurements in DMF the complexes may be formulated as [Ni(L)2Cl2] and [M(L)2]X2 (where M = Co (II), Cu (II), Cd (II), Pt (II) and Pd(II) and X = Cl - , CH3COO - due to their non electrolytic nature respectively. The antimicrobial activities of the ligand and their complexes have been studied by screening the compounds against the bacteria E. coli and S. aureus and also the fungi Asperillius niger and candida albicans and results have been compared with standard drug streptomycin and fluconazole. The data indicate that the metal complexes have higher antimicrobial activity than the free ligand and the standard drug. The DNA cleavage experiments, performed using gel electrophoresis with the corresponding metal complexes in the presence of H2O2 showed that all the complexes afford a pronounced discernible DNA cleavage evidenced by the disappearance of form I (supercoiled) of DNA and the production of formII (Linear).

Studies on chemical constituents possessing DNA cleavage activity / 中草药

Object To study the chemical structures and DNA cleavage activity of the water-soluble constituents from Polygonum bistorta L.Methods To isolate the constituents by reverse phase chromatography, and characterize their structures by the analysis of chemical property and spectral data.Results Ten compounds were isolated from the 60% acetone extract of the rhizoma from P.bistorta.Their structures were elucidated as gallic acid (Ⅰ), tryptophan (Ⅱ), 2, 6-dihydroy-bezoic acid (Ⅲ), (+)-catechin (Ⅳ), chlorogenic acid (Ⅴ), (-)-epicatechin-5-O-?-D-glucopyranoside (Ⅵ), (+)-catechin-7-O-?-D-glucopyranoside (Ⅶ), 1-(3-O-?-D-glucopyranosyl-4, 5-dihydroxy-phenyl)-ethanone (Ⅷ), (+)-catechin-5-O-?-D-glucopyranoside (Ⅸ) and (-)-epicatechin (Ⅹ), respectively.Conclusion Compounds Ⅱ, Ⅲ, Ⅴ-Ⅹ were isolated from the plant for the first time.Compounds Ⅰ, Ⅳ, Ⅵ, Ⅶ, Ⅸ, Ⅹ showed significant DNA cleavage activity.