Exosomes are small membrane-bound vesicles secreted by most cell types. Exosomes contain various functional proteins, mRNAs and microRNAs (miRNAs) that could be used for diagnostic and therapeutic purposes. How we should store the samples before RNA isolation and whether those long term stored samples could be used for circulating RNA investigation because of RNase is unknown. The aim of the study was to determine the stability of circulating miRNA in exosomes and plasma. Exosomes were isolated from plasma samples by using ExoQuick Precipitation methods. RNA was extracted from exosomes and the corresponding plasma samples with a Qiagen miRNeasy Mini kit. The concentration of RNA was measured by a Qubit^® RNA HS Assay Kit, and quantitative PCR was used for individual miRNA expression level detection. Results showed that exosomal miRNA showed extra stability under different storage conditions and no significant influence on plasma miRNA, except for short term storage at 4 °C. It is thus indicated that exosome miRNAs can be good biomarkers based on their stability under various storage conditions. Full article

The aim of this study was to determine whether the increased serum cell-free fetal DNA (cffDNA) level of gravidas developed into early-onset preeclampsia (EOPE) subsequently in the early second trimesters is related to prenatal screening markers. Serum was collected from 1011 gravidas. The level of cffDNA and prenatal screening markers were analyzed in 20 cases with EOPE and 20 controls. All fetuses were male. The maternal serum cffDNA level was assessed by amplification of the Y chromosome specific gene. Correlations between the variables were examined. (Logged) cffDNA in EOPE (median, 3.08; interquartile range, 2.93–3.68) was higher than controls (median, 1.79; interquartile range, 1.46–2.53). The increased level of (logged) cffDNA was correlated significantly with the increased human chorionic gonadotropin (HCG) level (r = 0.628, p < 0.001). Significant reciprocal correlations between cffDNA and babies’ birth weight as well as gestation weeks at delivery were noted (r = −0.516, p = 0.001; r = −0.623, p < 0.001, respectively). The sensitivity and specificity of cffDNA to discriminate between the EOPE cases and the controls were 90% and 85%, respectively. CffDNA is a potential marker for EOPE, which had a significant reciprocal correlation with babies’ birth weight and gestation weeks at delivery. Moreover, it may help in indicating the underlying hypoxic condition in the placenta. Full article

Toxins produced by bacteria and fungi are one of the most important factors which may cause food contamination. The study of detection methods with high sensitivity and throughput is significant for the protection of food safety. In the present study, we coupled microarray with emulsion PCR and developed a high throughput detection method. Thirteen different gene sites which encode the common toxins of several bacteria and fungi were assayed in parallel in positive and maize samples. Conventional PCR assays were carried out for comparison. The results showed that the developed microarray method had high specificity and sensitivity. Two zearalenone-related genes were investigated in one of the ten maize samples obtained with this present method. The results indicated that the emulsion based microarray detection method was developed successfully and suggested its potential application in multiple gene site detection. Full article

Single nucleotide polymorphisms (SNPs) are important markers which can be used in association studies searching for susceptible genes of complex diseases. High-throughput methods are needed for SNP genotyping in a large number of samples. In this study, we applied polyacrylamide gel-based microarray combined with dual-color hybridization for association study of four BDNF polymorphisms with autism. All the SNPs in both patients and controls could be analyzed quickly and correctly. Among four SNPs, only C270T polymorphism showed significant differences in the frequency of the allele (χ² = 7.809, p = 0.005) and genotype (χ² = 7.800, p = 0.020). In the haplotype association analysis, there was significant difference in global haplotype distribution between the groups (χ² = 28.19，p = 3.44e-005). We suggest that BDNF has a possible role in the pathogenesis of autism. The study also show that the polyacrylamide gel-based microarray combined with dual-color hybridization is a rapid, simple and high-throughput method for SNPs genotyping, and can be used for association study of susceptible gene with disorders in large samples. Full article

In this paper we describe a novel method for detecting many DNA fragments through efficient amplification by using an emulsion system based on “on-chip” PCR instead of conventional multiplex polymerase chain reaction (PCR). During the preparation of on-chip PCR, a set of primers were immobilized on a slide and other sets were in an emulsion system. Different emulsion phase primers and other related PCR components were dispersed in different droplets of the emulsion system, and then, due to the thermal instability of emulsion droplets, they would be released onto the surface of the slide after preheating in the first PCR step. To test the above method, we used plasma DNAs from pregnant women who was carrying a male fetus for gender identification. Four different Y chromosome DNA fragments were selected. Results showed that different DNA fragments could be simultaneously amplified with satisfactory results. It is suggested that a simple, convenient and inexpensive on-chip PCR method has been developed. Full article

The sequence specific recognitions between DNAs and proteins play important roles in many biological functions. The use of double-stranded DNA arrays (ds-DNA arrays) for studying sequence specific recognition between DNAs and proteins is a promising method. Here we report the use of a ds-DNA probe with multi operation sites of restriction proteins in the middle sequence to investigate DNA-protein sequence-specific interactions including methylation. We arranged EcoR I site and Rsa I site on the same duplex DNA probe to fabricate ds-DNA arrays. We used the ds-DNA arrays to study DNA-restriction enzyme reactions before and after duplex DNA methylation under different probe concentration and reaction time conditions. Our results indicated that the ds-DNA arrays can be further biochemically modified and made accessible for interactions between DNAs and proteins in complex multi-step gene-regulation processes. Full article