Rapid identification of diarrheagenic Escherichia coli based on barcoded magnetic bead hybridization

Diarrhea, as a global public health problem, causes a large number of infections and deaths every year. Although Escherichia coli (E. coli) is one of the normal flora microorganisms in the human intestinal tract, it has five pathogenic bacteria types that can cause human diarrhea, known as diarrheagenic E. coli. When people are infected, rapid and accurate diagnosis, along with timely treatment, are especially important. Here, we introduce a new method to identify and analyze a large number of pathogenic strains in E. coli by multiplex PCR and barcoded magnetic bead hybridization. Results show that the detection sensitivities of enterohemorrhagic E. coli, enterotoxigenic E. coli, enteropathogenic E. coli, enteroinvasive E. coli and enteroaggregative E. coli were 1.3 × 10³ CFU/mL, 2 × 10⁴ CFU/mL, 4 × 10⁴ CFU/mL, 7.2 × 10⁴ CFU/mL and 1.7 CFU/mL respectively. This method has strong specificity and high sensitivity and detects multiple target sequences in one experiment. Compared with other methods, BMB array has great application potential.     

An antibody microarray,in multiwell plate format,for multiplex screening of foodborne pathogenic bacteria and biomolecules

Intoxication and infection caused by foodborne pathogens are important problems worldwide, and screening tests for multiple pathogens are needed because foods may be contaminated with multiple pathogens and/or toxic metabolites. We developed a 96-well microplate, multiplex antibody microarray method to simultaneously capture and detect Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. typhimurium), as well as a biomolecule (chicken immunoglobulin G or IgG employed as a proteinaceous toxin analog) in a single sample. Microarrayed spots of capture antibodies against the targeted analytes were printed within individual wells of streptavidin-coated polystyrene 96-multiwell microtiter plates and a sandwich assay with fluorescein- or Cy3-labeled reporter antibodies was used for detection. (Printing was achieved with a conventional microarray printing robot that was operated with custom-developed microplate arraying software.) Detection of the IgG was realized from ca. 5 to 25 ng/mL, and detection of E. coli O157:H7 and S. typhimurium was realized from ca. 10⁶ to 10⁹ and ca. 10⁷ to 10⁹ cells/mL, respectively. Multiplex detection of the two bacteria and the IgG in buffer and in culture-enriched ground beef filtrate was established with a total assay (including detection) time of ca. 2.5 h. Detection of S. typhimurium was largely unaffected by high concentrations of the other bacteria and IgG as well as the ground beef filtrate, whereas a small decrease in response was observed for E. coli O157:H7. The multiwell plate, multiplex antibody microarray platform developed here demonstrates a powerful approach for high-throughput screening of large numbers of food samples for multiple pathogens and toxins.     

Ancient DNA profiling by megaplex amplications

Simultaneous amplification of nine human short tandem repeat (STR) DNA sequences and the amelogenin locus allows reducing to an absolute minimum the amount of sample material that is necessary for genetic identification or kinship analysis. Valuable remains can be studied this way without any visible damage, as is demonstrated by typing the DNA of a tooth root from the Saxon warrior Widukind, who died about 1200 years ago. The broad applicability of the megaplex approach is shown by typing bone and teeth specimens ranging from a few months to 3000 years of age employing AmpFlSTR Profiler Plus. Additionally, megaplex STR typing is the method of choice for proving the authenticity of molecular results derived from ancient degraded DNA.     

八路异步数据统计复接器设计

本文介绍了多路复接的基本原理,用具有最佳复用效率的统计复用方式设计了一个复合数据为同步／异步可选的八路异步数据复接器,该复接器具有４种工作方式：（１）复合数据为同步方式的疏数据复接;（２）复合数据为同步方式的发数据复接;（３）复合数据为异步方式的收数据复接;（４）复合数据为异步方式的发数据复接。工作方式灵活,可广泛用于卫星寻呼数据广播、低速数据采集、点对点数据传输等场合。     

Development of the 16 X‐STR loci typing system and genetic analysis in a Shanghai Han population from China

This study developed a new multiplex PCR system that simultaneously amplifies 16 X‐STR loci in the same PCR reaction, and the polymorphism and mutation rates of these 16 X‐STR loci were explored in a Shanghai Han population from China. These loci included DXS10134, DXS10159, DXS6789, DXS6795, DXS6800, DXS6803, DXS6807, DXS6810, DXS7132, DXS7424, DXS8378, DXS9902, GATA165B12, GATA172D05, GATA31E08, and HPRTB. Samples from 591 unrelated individuals (293 males and 298 females) and 400 two‐generation families were successfully analyzed using this multiplex system. Allele frequencies and mutation rates of the 16 loci were investigated, with the comparison of allele frequency distributions among different populations performed. Polymorphism information contents of these loci were all >0.6440 except the locus DXS6800 (0.4706). Nine cases of mutations were detected in the 16 loci from the investigation of 9232 meioses. Pairwise comparisons of allele frequency distributions showed significant differences for most loci among populations from different countries and ethnic groups but not among the Han population living in other areas of China. These results suggest that the 16 X‐STR loci system provides highly informative polymorphic data for paternity testing and forensic identification in the Han population in Shanghai, China, as a complementary tool.     

上海贝尔零接触光传送引领睿智波分新纪元

近年来,随着运营商3G建设的全面部署、全业务运营的大力开展、视频/P2P等大颗粒分组业务的迅猛增长以及网络扁平化趋势的不断深化,波分网络在光承载中扮演了越来越重要的角色。本文分析了40G波分市场以及城域网中波分系统的发展趋势,介绍了上海贝尔零接触光传送平台。     

Development of multiplex PCR system with 15 X-STR loci and genetic analysis in three nationality populations from China

The aim of this study is to develop a new multiplex PCR system that simultaneously amplifies the 15 X-chromosome short tandem repeats (X-STRs) loci in the same PCR reaction, and to obtain the 15 X-STR loci database in three nationality populations from China. This multiplex system includes DXS7133, DXS6801, DXS981, DXS6809, DXS7424, DXS6789, DXS9898, DXS7132, GATA165B12, DXS101, DXS10075, DXS6800, GATA31E08, DXS10074, and DXS10079, which were successfully analyzed on 1251 DNA samples (670 males and 581 females) from Guangdong Han population, Xinjiang Uigur and Kazakh. The allele frequencies and mutation rates of the 15 loci were investigated, and the allele frequency distribution among different populations was compared. A total of 6-17 alleles for each locus were observed and altogether 170 alleles for all the selected loci were found. Thirteen cases with mutation of the above loci were detected in 11,850 meioses. Pairwise comparisons of the allele frequencies distribution showed significant differences in most loci among different populations. The results indicate that this multiplex system may provide high polymorphism information for kinship testing and relationship investigations, and it is necessary to gain allele frequency and mutation rate of different population for forensic application.     

Genotyping of α-thalassemia deletions using multiplex polymerase chain reactions and gold nanoparticle-filled capillary electrophoresis

A gold nanoparticle-filled capillary electrophoresis method combined with three multiplex polymerase chain reactions (PCRs) was established for simultaneous diagnosis of five common α-thalassemia deletions, including the -α^3.7 deletion, -α^4.2 deletion, Southeast Asian (- -^SEA), Filipino (- -^FIL) and Thai (- -^THAI) deletions. Gold nanoparticles (GNPs) were used as a pseudostationary phase to improve the resolution between DNA fragments in a low-viscosity polymer. To achieve the best CE separation, several parameters were evaluated for optimizing the separation conditions, including the capillary coating, the concentrations of polymer sieving matrix, the sizes and concentrations of GNPs, the buffer concentrations, and the pH. The final CE method for separating a 200-base pair (bp) DNA ladder and α-thalassemia deletions used a DB-17 capillary, 0.6% poly(ethylene oxide) (PEO) prepared in a mixture of GNP_32nm solution and glycine buffer (25 mM, pH 9.0) (80:20, v/v) as the sieving matrix with 1 μM YO-PRO-1 for fluorescence detection; the applied voltage was −10 kV (detector at anode side) and the separation temperature was 25 °C. Under these optimal conditions, 15 DNA fragments with sizes ranging from 0.2 kb to 3.0 kb were resolved within 11.5 min. The RSDs of migration times were less than 2.81%. A total of 21 patients with α-thalassemia deletions were analyzed using this method, and all results showed good agreement with those obtained by gel electrophoresis.     

复分接中数字化定时处理的参数化验证法

在复分接系统中，如同步数字系列，定时处理占有重要地位。数字化定时处理技术应用于ＡＳＩＣ设计时，传统方法需要的仿真代价太大。作者 定时验证的特殊性，提出了定时处理电路验证的概念。同时利用参数化方法对定时处理进行验证，大大缩短了仿真时间。