Malcolm Burns | PubMed Health

PubMed2006

A microarray-based detection system for genetically modified (GM) food ingredients.

A multiplex DNA microarray chip was developed for simultaneous identification of nine genetically modified organisms (GMOs), five plant species and three GMO screening elements, i.e. the 35S promoter, the nos terminator and the nptII gene. The chips also include several controls, such as that for the possible presence of CaMV. The on-chip detection was performed directly with PCR amplified products. Particular emphasis was placed on the reduction of the number of PCR reactions required and on the number of primers present per amplification tube. The targets were biotin labelled and the arrays were detected using a colorimetric methodology. Specificity was provided by specific capture probes designed for each GMO and for the common screening elements. The sensitivity of the assay was tested by experiments carried out in five different laboratories. The limit of detection was lower than 0.3% GMO for all tests and in general around 0.1% for most GMOs. The chip detection system complies with the requirements of current EU regulations and other countries where thresholds are established for the labelling of GMO.

Agrobacterium tumefaciens↗

PubMed2004

Generic scheme for independent performance assessment in the molecular biology laboratory.

BACKGROUND: A variety of proficiency testing schemes are available for specific molecular analyses, but there is an acute need for more widely accessible schemes to assess and demonstrate general competence in DNA analysis. METHODS: Fifteen laboratories, including academic, clinical, and commercial organizations, were recruited into the prototype assessment exercise. A range of test samples were provided, and participants were required to extract DNA from simple matrices, perform PCR amplification, and score the samples as positive or negative by electrophoretic analysis of the amplification products. Results were requested as both gel images and a completed results table, and the performance of each laboratory was then scored on the submitted analytical results. RESULTS: Overall, laboratories performed the analysis successfully, with participants scoring a high proportion of the samples correctly in the two rounds of the scheme. However, not all of the laboratories were able to achieve amplification for all samples, and the performance of some laboratories was not consistent in the two rounds. In addition, several analytical problems were encountered at all stages of the process, including DNA extraction, PCR amplification, and correct recording of results. CONCLUSIONS: The generic approach described here has enabled effective cross-sectoral benchmarking of laboratories from a variety of analytical sectors. The problems encountered by some participating laboratories highlight the need for quality control and checks at all stages of the process to ensure accuracy of results. A statistical analysis of the results (ANOVA) allowed meaningful comparison of the consistency and sensitivity achieved by laboratories, demonstrating that an effective balance was achieved between the level of data obtained from laboratories and the time expenditure required from participants.

Chemistry, Clinical↗