ABSTRACT
BACKGROUND: Seeds were an important medium for long-distance transmission of plant viruses. Therefore, appropriate, more sensitive methods for detecting low concentrations of virus-infected in seeds were crucial to ensure the quality of seed lots. In this study, we have developed a one-step pre-amplification reverse transcription quantitative PCR (RT-qPCR) assay based on the TaqMan technology to detect Cucumber green mottle mosaic virus (CGMMV) in zucchini seeds. RESULT: Seed powder samples with simulated CGMMV-infected at a low concentration were prepared (the mass ratio 1:900 and 1:1000), and their uniformity were verified using one-step pre-amplification RT-qPCR. We used one-step pre-amplification RT-qPCR to detect CGMMV in low-concentration virus-infected seeds and compared this method with universal RT-qPCR and double antibody sandwich-enzyme-linked immunosorbent (DAS-ELISA) assay, the main methods used for virus detection in seeds. The minimum limit of detection (LOD) of the improved one-step pre-amplification RT-qPCR assays for simulated CGMMV-infected seeds in large lots seeds samples were 0.1%. CONCLUSIONS: One-step pre-amplification RT-qPCR assays could reliably and stably detected a single CGMMV-infected seed in 1000 seeds and demonstrated a higher detection sensitivity than universal RT-qPCR (infected seeds versus healthy seeds 1:900) and DAS-ELISA assay (infected seeds versus healthy seeds 1:500). Our improved one-step pre-amplification RT-qPCR assay have proved to be very suitable for the analysis of large seed lots.
ABSTRACT
Intracerebral hemorrhage accounts for about 10%-30% of all stroke types.It is characterized by rapid onset, rapid progress, varied clinical symptoms, high morbidity and mortality, and poor prognosis.After the intracerebral hemorrhage, various inflammatory mediators result in white matter lesions and cognitive impairment.Thrombin acting on thrombin receptors at low concentration induces neuroprotection and at high concentration causes brain injury.This article reviews the role and mechanism of thrombin in white matter injury after intracerebral hemorrhage.
ABSTRACT
Objective To investigate antibiotic resistance and Staphylococcal cassette chromosome mec (SCC-mec) genotype of methicillin-resistant Staphylococcus aureus (MRSA)in Dalian Area .Methods Antimicrobial susceptibility of MRSA was detected by Kirby-Bauer method and SCCmec genotype by multiple PCR method .Results 38 strains of MRSA were all multidrug-resistant strains ,but susceptible to vancomycin and chloramphenicol .The most common SCCmec genotype was type Ⅱ (86 .84% ) ,type Ⅲwas in the second place(10 .53% ) ,and unidentified type accounted for 2 .6% .Conclusion MRSA strains in Dalian area are charac-terized by multidrug resistance ,type Ⅱ is the most common SCCmec genotype .
ABSTRACT
Objective To develop the PCR-denaturing high performance liquid chromatography (DHPLC) for detection of E. Coli O157: H7. Methods The virulence genes of Shiga-like toxin(SLT) and rfbE were specifically amplified by 2 sets of primers. The target gene fragments of the PCR assay were 224 bp and 499 bp, respectively. Results Analysis of 37 strains demonstrated that this PCR system was specific. The detection limit of the PCR was 4 CFU/ml. Conclusion These results indicated that the multiplex PCR-DHPLC assay can be used for specific and sensitive detection of E. Coli O157:H7.
