Identification of a new peptide deformylase gene from enterococcus faecium and establishment of a new screening model targeted on PDF for novel antibiotics / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To identify a new peptide deformylase (PDF) gene (Genebank Accession AY238515) from Enterococcus faecium and to establish a new screening model targeted on PDF.</p><p><b>METHODS</b>A new PDF gene was identified by BLAST analysis and PCR and was subsequently over-expressed in the prokaryotic expression host E. coli B121(DE3). Over-expressed protein was purified for enzymatic assay by metal affinity chromatography and a new screening model was established for novel antibiotics.</p><p><b>RESULT</b>A new PDF gene of Enterococcus faecium was identified successfully. Ten positive samples were picked up from 8000 compound library and the microbial fermentation broth samples.</p><p><b>CONCLUSION</b>A new PDF of gene Enterococcus faecium was first identified and the model had a high efficacy. Positive samples screened may be antibacterial agents of broad spectrum.</p>

HPLC-fluorescent spectrometric determination of serum mexiletine concentration after derivatization with fluram / 药学学报

<p><b>AIM</b>To establish an HPLC-fluorescent spectrometric method for the determination of mexiletine hydrochloride in plasma after derivatization with fluram.</p><p><b>METHODS</b>Fluram acetone solution was added to the deproteinized plasma with acetone to obtain the derivative of mexiletine. The HPLC method was performed on a column of Allitima C18 (150 mm x 4.6 mm, 5 microns) with the mobile phase of methanol-water-diethylamine-phosphoric acid buffer (2.4 mol.L-1, pH 4.0) (70:28:2), and the detective wavelength were set at Ex 392 nm and Em 480 nm.</p><p><b>RESULTS</b>Mexiletine has a liner range over the concentration range from 0.100-6.400 mg.L-1. The lowest detectable concentration of this method was 5 micrograms.L-1 (S/N > or = 4). The intra-day and inter-day RSDs were 1.34%-5.31%, respectively.</p><p><b>CONCLUSION</b>This method is simple, selective and can be used for therapeutic drug monitoring (TDM) and pharmacokinetic studies of mexiletine.</p>

Spectrofluorimetric determination and kinetic study of ceftibuten

In this work, a simple and sensitive spectrofluorimetric method was developed to study ceftibuten degradation. It was also applied for the indirect determination of drug in bulk and pharmaceutical capsules. The procedure was based on the reaction of the degraded product with the fluorogenic reagent, fluorescamine. The proposed analytical method was optimized and validated. The detection limit was 0.1035 mug/ml. The activation energy for the degradation was 2.607 Kcal mol1

Separación de aminoácidos mediante cromatografía líquida de alta resolución / Amino acid analysis by high-performance liquid chromatography

Se presenta una compilación de la aplicación de la cromatografía líquida de alta resolución en el análisis de aminoácidos. Se analizan las formas de derivatización, se comparan los distintos derivados según sus alcances y limitaciones, la forma de detección y los distintos modos cromatográficos: cromatografía de intercambio iónico, cromatografía en fase normal, cromatografía en fase reversa y cromatografía en fase quiral. También se presentan los métodos automatizados comerciales más recientes para este tipo de análisis. Se dan ejemplos de aplicación de interés en el campo clínico-bioquímico, con el análisis de muestras de líquido cafalorraquídeo, de orina y de plasma/sangre o manchas de sangre seca. El análisis de los aminoácidos de hidrolizados de proteínas y de péptidos resulta más complejo y las condiciones de hidrólisis juegan un rol muy importante en los resultados, que son tratados en esta compilación. Se incluyen, además, aspectos referidos al análisis de los aminoácidos lábiles en proteínas, la preparación de las muestras, las recomendaciones prácticas al hacer HPLC y la influencia de los buffers