Modification of Gold Nanoparticle Loaded on Activated Carbon with Bis(4-methoxysalicylaldehyde)-1,2-Phenylenediamine as New Sorbent for Enrichment of Some Metal Ions

In this study, a new sorbent based on the gold nanoparticle loaded in activated carbon (Au-NP-AC) was synthesized and modified by bis(4-methoxy salicylaldehyde)-1,2-phenylenediamine (BMSAPD). This sorbent, which is abbreviated as Au-NP-AC-BMSAPD, has been applied for the enrichment and preconcentration of trace amounts of Co²⁺, Cu²⁺, Ni²⁺, Fe²⁺, Pb²⁺, and Zn²⁺ ions in real samples. All metal ions under study were retained on the Au-NP-AC-BMSAPD sorbent by complexation of the ions with the BMSAPD ligand, providing an efficient preconcentration fashion. The retained metal ions were then eluted from the sorbent by HNO₃ and detected by flame atomic absorption spectrometry. The analytical parameters including pH, amount of ligand, and the nature of the eluent and solid phase were evaluated to obtain the optimum condition for the preconcentration factor. Following the optimum conditions, a preconcentration factor of 200 was obtained for all the metal ions under study with detection limits of 1.4–2.6 ng mL⁻¹. The method has been successfully applied for the extraction and determination of the ion content in the same real samples with recoveries in the range of 95–99.6% and a relative standard deviation lower than 4.0%.     

9-fluorenylmethyl chloroformate as a fluorescence-labeling reagent for derivatization of carboxylic acid moiety of sodium valproate using liquid chromatography/tandem mass spectrometry for binding characterization: a human pharmacokinetic study

In High Performance Liquid Chromatographic (HPLC) determination of chemicals with acidic functions, different labeling agents are used to improve sensitivity of the assay. 9-Fluorenylmethyl chloroformate (FMOC-Cl), on the other hand, is a suitable labeling agent, which reacts with both primary and secondary amines and less readily with hydroxyl groups in alkaline conditions. However, the reagent has not been applied in labeling of chemicals with acidic function yet. In this study which is the first report on application of FMOC-Cl in derivatization and analysis of a drug with acidic function, valproic acid (VPA), one of a series of fatty carboxylic acids with anticonvulsant activity, was derivatized using the reagent and quantified in serum samples by HPLC with fluorescence detection. In addition, to document the reaction between the labeling agent and carboxylic acid moiety of the drug, we developed a liquid chromatography-tandem MS/MS (LC-MS/MS) method. Following liquid-liquid extraction, derivatization of the drug and an internal standard was achieved in alkaline medium. The elute was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The present method is more sensitive comparing with other published HPLC procedures for analysis of VPA. The assay is sensitive enough to measure drug levels obtained in human single dose studies with a limit of quantification of 0.01 μg/mL. Also the method is linear over the concentrations range of 0.01-32 μg/mL of VPA in human serum using 100 μL serum sample and 5 μL injection. The coefficient variation values of both inter and intra day analysis were less than 12% and the percentage error was less than 4%. The method performance was studied and the validated procedure applied in a randomized cross-over bioequivalence study of two different VPA preparations in 24 healthy volunteers.     

Candidate gene prioritization

Candidate gene identification is typically labour intensive, involving laboratory experiments required to corroborate or disprove any hypothesis for a nominated candidate gene being considered the causative gene. The traditional approach to reduce the number of candidate genes entails fine-mapping studies using markers and pedigrees. Gene prioritization establishes the ranking of candidate genes based on their relevance to the biological process of interest, from which the most promising genes can be selected for further analysis. To date, many computational methods have focused on the prediction of candidate genes by analysis of their inherent sequence characteristics and similarity with respect to known disease genes, as well as their functional annotation. In the last decade, several computational tools for prioritizing candidate genes have been proposed. A large number of them are web-based tools, while others are standalone applications that install and run locally. This review attempts to take a close look at gene prioritization criteria, as well as candidate gene prioritization algorithms, and thus provide a comprehensive synopsis of the subject matter.     

Differential proteome analysis of a selected bacterial strain isolated from a high background radiation area in response to radium stress

The present study describes the response of a bacterial strain, isolated from a hot spring in an area with the highest levels of natural radiation, under radium ((226)Ra) stress. The bacterium has been characterized as a novel and efficient radium biosorbent and identified as a variant of Serratia marcescens by biochemical tests and molecular recognition. In order to gain insights into key cellular events that allow this strain to survive and undergo (226)Ra adaptation and biosorption, the strain was tested under two experimental conditions of 1000 and 6000 Bq (226)Ra stress. A proteomic approach involving two-dimensional polyacrylamide gel electrophoresis and mass spectrometry was used to identify the differentially expressed proteins under (226)Ra stress. Functional assessment of identified proteins with significantly altered expression levels revealed several mechanisms thought to be involved in (226)Ra adaptation and conferring resistant phenotype to the isolate, including general stress adaptation, anti-oxidative stress, protein and nucleic acid synthesis, energy metabolism, efflux and transport proteins. It suggests that this strain through evolution is particularly well adapted to the high background radiation environment and could represent an alternative source to remove (226)Ra from such areas as well as industrial radionuclide polluted wastewaters.     

Draft Genome Sequence of Ureibacillus thermosphaericus Strain Thermo-BF, Isolated from Ramsar Hot Springs in Iran

Ureibacillus thermosphaericus strain Thermo-BF is an aerobic, thermophilic bacillus which has been characterized to biosynthesize gold nanoparticles. Here we present the draft genome sequence of Ureibacillus thermosphaericus strain Thermo-BF which consists of a 2,864,162-bp chromosome. This is the first report of a shotgun sequenced draft genome of a species in the Ureibacillus genus.     

Biological activity of quercetin-3-<Emphasis Type="Italic">O</Emphasis>-glucoside,a known plant flavonoid

Cytotoxic, phytotoxic, antimicrobial and antioxidant effects of quercetin 3-O-glucoside (Q3G) isolated by HPLC from aerial parts of Prangos ferulaceae was studied by MTT assay, lettuce germination assay, disk diffusion and DPPH method. Our results showed that Q3G exhibits high antioxidant effect with RC₅₀ of 22 μg/mL, it has low cytotoxicity and no antibacterial effects. Q3G exhibits high phytotoxic effect with IC₅₀ value of 282.7 μg/ml, as well. It is assumed that Q3G does not play a defense role in plants and it may act as an allelopatic agent. The article is published in the original.     

Coleopteran-specific and putative novel cry genes in Iranian native Bacillus thuringiensis collection

The characterization of the strains containing Coleopteran-specific and also putative novel cry genes in Iranian native Bacillus thuringiensis collection is presented. Characterization was based on PCR analysis using 31 general and specific primers for cry1B, cry1I, cry3A, cry3B, cry3C, cry7A, cry8A, cry8B, cry8C, cry14, cry18, cry26, cry28, cry34 and cry35 genes, protein band patterns as well as their insecticidal activity on Xanthogaleruca luteola Mull. larvae. Forty six isolates (65.7%) contained minimum one Coleopteran-active cry gene. Based on universal primers, strains containing cry18 and cry26 genes were the most abundant and represent 27.1% and 24% of the isolates, respectively, whereas cry14, cry3, cry28, cry34, cry35, cry7, cry8 genes were less abundant, found in 14.2, 12.5, 10, 7, 7 and 5.6% of the strains, respectively. Based on specific primers, isolates containing cry1I were the most abundant (48.5%). Two strains containing Coleopteran-active cry genes showed higher activity against X. luteola larvae than B. thuringiensis subsp. morrisoni pathovar tenebrionis. Thirty isolates, when assayed for cry1C, cry5, cry6, cry8b, cry9, cry10, cry11, cry18, cry24 and cry35 genes, showed unexpected size bands. Cloning and sequencing of the amplicons allowed both the identification of known cry genes and the detection of putative novel cry1C sequences.     

Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate

Most of the published methods for analysis of gabapentin, an antiepileptic agent, in human serum are based on the same approach, involving o-phthaldialdehyde derivatization of deproteinized serum samples. The present paper however, describes a new, simple and sensitive high-performance liquid chromatographic method for determination of gabapentin in human serum using liquid-liquid extraction and 9-fluorenylmethyl chloroformate (FMOC-Cl) as pre-column labeling agent. The drug and an internal standard (azithromycin) were extracted from serum by salting-out approach using a mixture of dichloromethane-2 propanol (1:1, v/v) as the extracting solvent. The extracted analytes were subjected to derivatization with FMOC-Cl in the presence of phosphate buffer (pH 7). A mobile phase consisting of methanol-0.05 M sodium phosphate buffer (73/27, v/v; pH of 3.9) containing 1 ml/l triethylamine was eluted and chromatographic separation was performed on a Shimpack CLC-C18 (150 mm x 4.6 mm) column. The standard curve was linear over the range of 0.03-20 microg/ml and limit of quantification was 0.03 microg/ml. The performance of analysis was studied and the validated method showed excellent performance in terms of selectivity, specificity, sensitivity, precision and accuracy. No interferences were found from commonly co-administered antiepileptic agents.     

Sensitive microanalysis of gabapentin by high-performance liquid chromatography in human serum using pre-column derivatization with 4-chloro-7-nitrobenzofurazan: Application to a bioequivalence study

Most of the published methods for analysis of gabapentin, an antiepileptic agent, in human serum require automated o-phthalaldehyde derivatization of the drug and immediate injection of the unstable derivatives formed. A new, very sensitive and simple high-performance liquid chromatographic method for quantitation of the drug in human serum using 4-chloro-7-nitrobenzofurazan (NBD-Cl) as a fluorescent labeling agent is presented. In this method the sensitivity was significantly improved and the limit of quantification of 0.002 microg/ml was obtained using 100 microl serum sample and 10 microl injection. However, the LOQ can be improved by increasing the sampling volume. The procedure involved protein precipitation of serum by acetonitrile followed by derivatization with NBD-Cl. Amlodipine was used as internal standard and chromatographic separation was performed on a Shimpack CLC-C18 (150 mm x 4.6 mm) column. The fluorescence derivative of the drug was monitored at excitation and emission wavelengths of 470 and 537 nm, respectively. A mobile phase consisting of methanol and sodium phosphate buffer (0.05 M; pH 2.5) containing 1 ml/l triethylamine (65:35, v/v) was used. The calibration curve was linear over the concentration range of 0.002-15 microg/ml. No interferences were found from commonly co-administrated antiepileptic drugs. The method was applied in a randomized cross-over bioequivalence study of two different gabapentin preparations in 24 healthy volunteers.     

A rapid high performance liquid chromatographic determination of methyldopa in human serum with fluorescence detection and alumina extraction: application to a bioequivalence study

A simple and ultra rapid high performance liquid chromatographic (HPLC) method coupled with alumina extraction and fluorescence detection was described for determination of methyldopa in human serum. The drug and an internal standard were adsorbed onto alumina and eluted using acidic methanol. The eluate was directly injected onto ODS reverse phase column using a mixture of phosphate buffer (0.05 M) containing triethylamine (100 microl/l, v/v; pH 2.3) and methanol (92:8, v/v) at a flow rate of 2.1 ml/min as the mobile phase. The fluorescence detector excitation and emission wavelengths were set at 270 and 320 nm, respectively. No interference in the assay from any endogenous substances or other concurrently used drugs was observed and the retention times of I.S. and the drug were 1.7 and 2.4 min, respectively with total run time (injection to injection) of less than 3.5 min. The limit of quantification was evaluated to be 2 ng/ml. Validity of the method was studied and the method was precise and accurate with a linearity range from 20 ng/ml to 5000 ng/ml. This method has been used in a randomized crossover bioequivalence study of two different methyldopa preparations in 24 healthy volunteers.