Analysis of real time PCR amplification efficiencies from three genomic region of dengue virus / Análisis de las eficiencias de amplificación por PCR en tiempo real de tres regiones genómicas del virus dengue

Early diagnosis of dengue virus (DENV) infection represents a key factor in preventing clinical complications attributed to the disease. The aim of this study was to evaluate the amplification efficiencies of an in-house quantitative real time-PCR (qPCR) assay of DENV, using the non-structural conserved genomic region protein-5 (NS5) versus two genomic regions usually employed for virus detection, the capsid/pre-membrane region (C-prM) and the 3’-noncoding region (3’NC). One-hundred sixty seven acute phase serum samples from febrile patients were used for validation purposes. Results showed that the three genomic regions had similar amplification profiles and correlation coefficients (0.987-0.999). When isolated viruses were used, the NS5 region had the highest qPCR efficiencies for the four serotypes (98-100%). Amplification from acute serum samples showed that 41.1% (67/167) were positive for the universal assay by at least two of the selected genomic regions. The agreement rates between NS5/C-prM and NS5/3’NC regions were 56.7% and 97%, respectively. Amplification concordance values between C-prM/NS5 and NS5/3’NC regions showed a weak (k= 0.109; CI 95%) and a moderate (k= 0.489; CI 95%) efficiencies in amplification, respectively. Serotyping assay using a singleplex NS5-TaqMan® format was much more sensitive than the C-prM/SYBR Green® I protocol (76%). External evaluation showed a high sensitivity (100%), specificity (78%) and high agreement between the assays. According to the results, the NS5 genomic region provides the best genomic region for optimal detection and typification of DENV in clinical samples.

El diagnóstico precoz de la infección por el virus dengue (DENV) constituye un elemento clave para la prevención de las complicaciones clínicas propias de la enfermedad. El objetivo del estudio fue evaluar la detección de DENV mediante un ensayo cuantitativo de PCR-tiempo real (qPCR), desarrollado localmente, utilizando la región no-estructural-5 (NS5), versus dos regiones tradicionalmente empleadas para la detección del virus, la región cápside/pre-membrana (C-prM), y la región noncodificante-3’ (3’NC). Se recolectaron 167 muestras de suero de pacientes en fase aguda de la enfermedad. Las tres regiones génicas tuvieron perfiles de amplificación/coeficientes de correlación similares (0,987-0,999). Sin embargo, la región NS5 tuvo la eficiencia de amplificación más elevada para los cuatro serotipos (98-100%). Durante el proceso de validación, 41,1% (67/167) de las muestras de suero resultaron positivas para DENV al menos por dos de las regiones genómicas empleadas. Los valores de concordancia entre las regiones NS5/C-prM y NS5/3’NC fueron de 56,7% y 97%, respectivamente. La concordancia fue débil entre las regiones NS5/C-prM (k= 0,109; CI 95%), sin embargo, fue moderada entre las regiones NS5/3’NC (k= 0,489; CI 95%). El ensayo de tipificación uniplex en formato NS5/TaqMan® mostró alta sensibilidad (100%) que el protocolo C-prM/SYBRGreen®-I (76%). La validación externa del ensayo mostró una alta sensibilidad (100%), especificidad (78%) y acuerdo alto entre los ensayos utilizados. De acuerdo a los resultados obtenidos, la región NS5 ofrece la mayor opción para la detección y serotipificación del DENV en muestras clínicas.

Progress of genome-wide association studies in type 2 diabetes mellitus / 中华内分泌代谢杂志

Genome-wide association studies ( CWAS) use high-throughout genotyping technologies to investigate the relation of hundreds of thousands of gene markers(genotype) with clinical conditions and measurable traits (phenotype). Type 2 diabetes mellitus results from the interaction of environmental factors with genetic variants. Many progresses have been acquired from GWAS. New gene regions have been discovered to be involved in the development and function of islet (3-cells, which provides new strategies for the etiology investigation, prevention, and treatment of type 2 diabetes mellitus.

cDNA-AFLP Reveals Variation of Sequence Region trnF-ndhJ in Cytoplasmic Male Sterile Chinese Cabbage-pak-choi / 生物化学与生物物理进展

By means of cDNA amplified fragment length polymorphism(cDNA-AFLP) technique, a fragment P1708 was amplified from Polima cytoplasmic male sterile Chinese cabbage-pak-choi (Brassica campestris L. ssp. chinenesis Makino, syn, B. rapa L. ssp. chinenesis) 'Bpol97-05A'. RT-PCR showed that this fragment was specifically expressed in male sterile material. Sequencing and BLAST search in GenBank database indicated that P1708 had 100% homolog with chloroplast ndhJ-trnF gene region except a 54 bp insertion. Gene specific primer pairs were synthesized according to ndhJ-trnF gene region and two fragments about 1 900 bp were amplified respectively using genomic DNA templates of Polima cabbage and male fertile oilseed rape. The sequencing results showed that the gene region ndhJ-trnF of Polima cabbage contained two 54 bp repeats and some variation sites. The repeat part shared the same sequence as trnF gene except three bases at 5′ ends. For the insertion of 108 bp sequence, a new open reading frame was created.