ABSTRACT
El modelo farmacológico de cultivo in vitro de P. falciparum es crucial en el tamizaje inicial de sustancias o extractos de plantas con posible actividad antiplasmodial. La densidad parasitaria puede determinarse mediante variadas metodologías, sin embargo, se han descrito numerosas ventajas y desventajas asociadas a cada una de ellas. Se evaluaron el tiempo de incubación necesario para la tinción y el uso de cultivos asincrónicos o sincrónicos en busca de valores óptimos; evidenciando un tiempo óptimo de 2 h, y límites de detección y cuantificación, menores en cultivos asincrónicos. Empleando las cepas FCR3 y FCB2 se evidenció un ruido de fondo de 12% y 38% respectivamente; la linealidad mostró una buena correlación, r² de 0,9644 (FCR3) y 0,9841 (FCB2) y una pendiente de 1761,8 y 852,4 respectivamente. Además, se comprobó había concordancia entre los métodos, fluorométrico con SYBR Green I (SYBRG I) y microscópico con Giemsa, con diferencia media de 0,00002% y 0,09109% para FCR3 y FCB2 respectivamente. Los límites de detección y cuantificación fueron 0,5% y 1,5% de parasitemia. El factor Z con FCB2 fue 0,376, en tanto que con FCR3 alcanzó 0,702. La concentración inhibitoria 50 (CI50) frente a P. falciparum FCR3, generada por cloroquina (CQ) fue 0,37 mcg/mL por microscopía y 0,35 mcg/mL por fluorometría. Nuestros hallazgos sugieren que el ensayo de fluorescencia con SYBRG I, empleando fluorómetros comúnmente disponibles en muchos laboratorios, es preciso, robusto, rápido y exacto; para la evaluación in vitro de sustancias o extractos con posible actividad antiplasmodial.
The in vitro pharmacological model of P. falciparum culture is crucial in the initial screening for substances or plant extracts with possible antiplasmodial activity. The parasite density can be determined by varied methods, however have been described numerous advantages and disadvantages associated with each of them. The incubation time required for staining and the use of synchronous or asynchronous cultures were assessed for optimal settings; showing optimal time of 2 h, and lower limits of detection and quantification in asynchronous cultures. Employing the FCB2 and FCR3 strains, was evidenced a background noise of 12% and 38% respectively; linearity showed a good correlation, r² of 0.9644 (FCR3) and 0.9841 (FCB2) and a slope of 1761.8 and 852.4, respectively. It was evidenced agreement between the methods, fluorometric with SYBR Green I (SYBRG I) and microscopic with Giemsa, the mean difference was 0.00002% and 0.09109% respectively for FCR3 and FCB2, The limits of detection and quantification were 0.5% and 1.5% of parasitaemia. The Z factor was 0.376 with FCB2, whereas with FCR3 reached 0.702. The inhibitory concentration 50 (IC50) against P. falciparum FCR3, generated by chloroquine (CQ), was 0.37 mcg/mL by microscopy and 0.35 mcg/mL by fluorometry. Our findings suggest that the SYBRG I fluorescence based assay, by using fluorometers commonly available in many laboratories, is precise, robust, fast and accurate; for the in vitro evaluation of substances or extracts with possible antiplasmodial activity.
ABSTRACT
Objective To develop SYBR Green I real-time PCR assay for detection and identification of Hepatitis B virus. Methods Based on the sequences of Hepatitis B virus gp1 gene,primers were designed.The reaction assay and thermal cyc-ling profile were optimized.The positive standard was from recombinant clone.Both the developed assay and Zhejiang kuake biotechnology company’s assay were applied in 100 patients serum.Results The detection limit was between 5×102 copies/ml to 5×108 copies/ml with a good liner correlation and no cross reaction.The whole process just needed 2.5 h.Comparing with the company products,the sensitivity and specificity of the developed assay were 100% and 92.5% respectively.Con-clusion The established assay is rapid,simple,high sensitivity and specificity.It is not only valuable for the identification of Hepatitis B virus patients,but also provide accurate quantitative analysis for HBV patients.
ABSTRACT
OBJECTIVE: To establish a rapid molecular method for identifying saffron (Crocus sativus L.) and its adulterants by PCR: amplification using specific primers and fluorescent dyes detection. METHODS: The chloroplast barcode was sequenced and analyzed to find the SNPs between saffron and its adulterants. Specific primers were designed for the SNPs, the PCR reaction systems were built and optimized, and fluorescent dyes method was used to identify PCR products. RESULTS: A 421 bp saffron identification band based on the psbA-trnH barcode sequence was screened when 100 × SYBR Green I was added into the optimized PCR product under the following condition; initial denaturation at 90℃ for 1 min, denaturation at 90℃ for 5 s, annealing at 58℃ for 5 s, 26 cycles; the saffron (Crocus sativus L.) showed strong green fluorescence under 365 nm UV lamp whereas adulterants did not. CONCLUSION: Fast site-specific PCR can rapidly identify saffron and its adulteration.
ABSTRACT
Objective: To construct a real-time fluorescence quantitative RT-PCR method for the β-actin gene of Panax ginseng. Methods: According to the β-actin gene of other higher plants available in Genbank, A pair of primers weredesigned and the amplified fragment of β-actin gene was linked with pMD20-T vector to construct recombinant plasmids. Then the positive plasmids were diluted and the standard curve was established. The sensitivity, specificity, and repeatability were detected. Results: The results showed that the lowest copy number for detection of β-actin gene with this method was 43.0 copies/μL, and there was a good linear relationship in a wide range from 43 to 4.3 × 107 copies/μL (R2 = 0.995 3). The melting curve showed a single peak with the temperature of (84.51 ± 0.01) ℃. The coefficient of variation (CV) of five different concentration of positive plasmids was 0.58% to 2.79% and 2.61% to 4.41% in intra-assay and inter-assay, respectively. Conclusion: The method established in this paper has the advantage of rapidity, sensitivity, specificity, high throughput, and good repeatability, which provides a methodological basis for the quantitative analysis on the functional genes of P. ginseng when β-actin gene is taken as a reference gene.
ABSTRACT
SYBR Green I Real Time-qPCR method was developed to quantify the numbers of copyies of AlkB ( alkanes degradation gene) and Nah ( naphthalene dioxygenase degradation gene) functional degradation gene corresponding to alkanes and aromatic hydrocarbons degradation. Two pairs of primers AlkBf/AlkBr and Nahf/Nahr were designed for AlkB and Nah amplification respectively, according to the nucleotide sequences of related degradation microorganisms published in GenBank. The purified recovery products of traditional PCR were combined with pEASY-T1 vectors and transformed in competent cells to amplify. The recombinant plasmids were extracted and used as positive templates to create standard curve through gradient dilution. The conditions for the real time PCR were as the follows: the final concentration of forward and reverse primers were 0. 2 μmol/L, 2×TransStart Top Green qPCR SuperMix, and the annealing temperatures of AlkB and Nah PCR were 50℃ and 57℃, respectively. The method showed a sensitivity of 100 times higher than that of the traditional PCR method and good repeatability. The numbers of copies of AlkB in three functional regions of an oilfield indicated that oil producing zone with serious oil pollution had the highest AlkB copy numbers, and residential zone with lighter oil pollution had the lowest AlkB copy numbers. Nah degradation gene distribution was more uniform.
ABSTRACT
A method for counting Infectious pancreatic necrosis virus (IPNV) through epifluorescence microscopy was analyzed in detail. Image processing and statistic considerations are included. The particle size of viruses was compared in different experimental conditions such as the staining of the virus with SYBR-Green I or with antibodies for specific fluorescence labeling of viral proteins. The type of surface used as mounting support was assayed as well. The results indicated that the most suitable method involves the mounting of the viral-containing suspension on a membrane filter followed by the staining with a monoclonal antibody specific for a viral protein combined with a FITC (fluorescein isothiocyanate)-conjugated secondary antibody.
Subject(s)
Aquabirnavirus , Aquabirnavirus/pathogenicity , Birnaviridae Infections/diagnosis , Birnaviridae Infections/genetics , Birnaviridae Infections , Salmonidae , Fluorescent Antibody Technique/methodsABSTRACT
<p><b>OBJECTIVE</b>To compare the applicability of the SYBR Green-I assay with the standard schizont maturation assay, for determination of sensitivity of Plasmodium vivax (P. vivax) to chloroquine and a new antifolate WR 99210.</p><p><b>METHODS</b>The study was conducted at Mae Tao Clinic for migrant workers, Tak Province during April 2009 to July 2010. A total of 64 blood samples (1 mL blood collected into sodium heparinized plastic tube) were collected from patients with mono-infection with P. vivax malaria prior to treatment with standard regimen of a 3-day chloroquine. In vitro sensitivity of P. vivax isolates was evaluated by schizont maturation inhibition and SYBR Green-I assays.</p><p><b>RESULTS</b>A total of 30 out of 64 blood samples collected from patients with P. vivax malaria were successfully analyzed using both the microscopic schizont maturation inhibition and SYBR Green-I assays. The failure rates of the schizont maturation inhibition assay (50%) and the SYBR Green-I assay (54%) were similar (P=0.51). The median IC10s, IC50s and IC90s of both chloroquine and WR99210 were not significantly different from the clinical isolates of P. vivax tested. Based on the cut-off of 100 nM, the prevalences of chloroquine resistance determined by schizont maturation inhibition and SYBR Green-I assays were 19 and 11 isolates, respectively. The strength of agreement between the two methods was very poor for both chloroquine and WR99210.</p><p><b>CONCLUSIONS</b>On the basis of this condition and its superior sensitivity, the microscopic method appears better than the SYBR Green-I Green assay for assessing in vitro sensitivity of fresh P. vivax isolates to antimalarial drugs.</p>
Subject(s)
Humans , Antimalarials , Pharmacology , Chloroquine , Pharmacology , Inhibitory Concentration 50 , Malaria, Vivax , Parasitology , Organic Chemicals , Parasitemia , Parasitology , Parasitic Sensitivity Tests , Plasmodium vivax , SchizontsABSTRACT
Objective Previous study showed that the histopathological basis of visual function damage caused by optical nerve injury is apoptosis of retinal ganglion cells(RGCs). This procedure is regulated by P53, bax and caspase 3 genes. Present study aimed to observe the expression of bax, P53 and caspase 3 mRNA in RGCs after traumatic optic nerve damage in the rats by SYBR green I fluorescence quantitative PCR method. Methods The animal model of optic nerve injury was established in the right eyes of 56 adult Wistar rats by a fluid percussion brain injury device (FPI) . Animal were killed on days 1, 3, 5, 7, 9, 14, 28 days separately after injury. Other 16 Wistar rats were divided into normal control group and sham operation group. The total RNA was isolated from rat fresh retina tissue by Trizol method and was treated by reverse transcription to cDNA using 01igo(dt) 18 as primer and then amplified. The target fragments of bax, P53 and caspase 3 cDNA were linked with carrier pTZ57 R/T to construct recombined plasmids which were transformated to E. Coli DH5α by T/A clone method. Recombined plasmids were extracted with alkaline lysis method and the plasmids were selected in white colonies by ampicillin screening, EcoR I restrictive enzyme analysis, and their specificity was evaluated using DNA sequencing. The standard curves were created by plasmid DNA and the precise expression level of target genes in samples were determined using software. The results were expressed as the ratios of target gene mRNA to GAPDH mRNA. Results The standard curve drawn by pTZ57R/T and target gene presented a good linear tendency with the higher sensitivity and specificity. The expression of P53 and bax mRNA began to increase on the third day after the injury of optic nerve and peaked on the fifth day and started to decline on the seventh day. The expression of caspase 3 mRNA increased from the fifth day through the ninth days after injury and declined on the fourteenth day. The significant differences were found in the expression of P53, bax and caspase 3 between model group and control group (P ＜ 0. 05) . Conclusion The pro-apoptotic protein P53, bax and caspase 3 play an important role in RGCs apoptosis.
ABSTRACT
Objective: To investigate whether the real-time polymerase chain reaction (R-PCR) assay with SYBR green I and melting curve analysis could be used for glutathione S-transferase M1 gene (GSTM1) polymorphism detection in Thai nasopharyngeal carcinoma (NPC) patients by comparing the results of this assay with the conventional PCR (C-PCR) assay. Methods: DNA samples from peripheral blood leukocytes of 60 Thai NPC patients were investigated in this study. GSTM1 polymorphism [GSTM1 normal genotype (GSTM1+) and GSTM1 null genotype (GSTM1-)] were examined by using the R-PCR assay with SYBR green I and melting curve analysis and the C-PCR assay. Results: The results of GSTM1 polymorphism detection by the R-PCR assay were in concordance with the C-PCR assay (k = 1.0). Twenty-six individuals with GSTM1+ in the R-PCR assay showed 2 peaks of melting point at 82.5oC and 87.5oC that correlated with the appearance of 2 DNA bands of GSTM1 [215 base pair (bp)] and b-globin (268 bp) in the C-PCR assay, respectively. In addition, thirty-four individuals with GSTM1- in the R-PCR assay showed only 1 peak of melting point at 87.5oC that correlated with the appearance of 1 DNA band of b-globin (268 bp) in the C-PCR assay. Moreover, we found that the R-PCR assay was a faster and safer method for detection of GSTM1 polymorphism than the C-PCR assay. Conclusion: The present study suggests that the R-PCR assay with SYBR Green I and melting curve analysis may be a useful screening tool for more convenient, rapid, reliable, and safer detection of GSTM1 polymorphism in Thai NPC as compared to the C-PCR assay.