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Lp was a generally recognized as safe microorganism. Lactobacillus plantarum 590 was obtained by inserting nisI gene into Lp genome to help it tolerate higher concentration nisin. As the unintended effects of the genetically modified microorganism (GMM) are the most important barriers to the progress of GMM, we have performed a useful exploration to establish a new in vivo evaluation model for GMM from the point of view of intestinal health. In this study, Sprague-Dawley rats were orally administered with Lp 590 and Lp for 4 weeks. Fecal samples were collected to determine the number of beneficial bacteria Bifidobacterium and harmful bacteria Clostridium perfringens. Denaturing gradient gel electrophoresis was used to detect the bacterial profiles of every group. Fecal enzyme activities and short-chain fatty acids as main metabolites were also examined. Real time PCR (RT-PCR) and immunohistochemistry were used to analyze two proteins (ZO-1 and occludin) and secretory immunoglobulin A to detect intestinal permeability and mucosal immunity, gut permeability and gut mucosal immunity were analyzed to see whether GM Lp 590 can induce changes of the gut health when compared with non-GM Lp group, andeventually we concluded that there is no significant difference between GM Lp 590-fed group and non-GM Lp-fed group. The conclusion of gut health test was comparable withthat from traditional subchronic test. Evaluation of intestinal health will be a new approach of assessing the safety of GMM.

Escherichia coli, Listeria monocytogenes, and Salmonella spp. are 3 kinds of the most important food-borne human pathogens. Traditional microbiological analysis is labor-intensive, time-consuming, and easily contaminated, thus producing false positive signals; it also involves much subjectivity judgments. Multiplex-PCR could be applied to detect multiple target organisms simultaneously to save time and labor, but there is always disproportionate amplification resulting from the disparity of different primers. To gain a rapid and sensitive method, a universal primer-multiplex PCR system (UP-M-PCR) was developed and applied for simultaneous detection of the 3 organisms. This method simplified traditional multiplex-PCR reaction system and overcame its amplification disparities among different primers; moreover, it got a high specificity and sensitivity (85, 155, and 104 copies/reaction for E. coli O157, L. monocytogenes, and Salmonella spp., respectively). Compared with the time-consuming and laborious microbiological analysis, UP-M-PCR had a lower risk of cross-contamination without inoculation and incubation. Test results for 36 food samples showed that UP-M-PCR method got a relative accuracy of 91.77% when compared with traditional microbiological analysis. It could serve as a rapid screening method for pathogen detection and could detect target genes even in dead pathogenic cells. In addition, it has the potential to be performed in an automation mode and might find broader application in simultaneous detection of other multiple pathogens.

BACKGROUND: The Cry toxins are already a useful alternative or supplement to synthetic chemical pesticide application in commercial agriculture and forest management. RESULTS: The Cry1ab/ac gene from Bacillus thuringiensis was cloned from the genome of genetically modified rice by polymerase chain reaction (PCR). Owing to the large number of Escherichia coli low-usage codons in the Cry1ab/ac gene, the first 20 codons were optimised by PCR to improve the expression of the Cry1ab/ac gene in E. coli. The Cry1Ab/Ac protein was highly expressed in E. coli as inclusion bodies that could be dissolved in 8 mol L−1 urea and purified on a His Trap™ FF crude column under denaturing conditions. The purified Cry1Ab/Ac protein was dialysed in refolding buffers to obtain a soluble and biologically active protein. To achieve better biological activity, the His-tag was digested from the Cry1Ab/Ac protein with enterokinase, and the Cry1Ab/Ac protein was further purified by gel filtration on a fast performance liquid chromatography Superdex 75 HR 10/30 column using an AKTA purifier. The identity of the purified Cry1Ab/Ac protein sequence was confirmed by western blot and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. The final purified Cry1Ab/Ac protein was 99.2% pure and retained its biological activity, as determined in a growth inhibition assay of Chilo suppressalis. CONCLUSION: The purified Cry1Ab/Ac protein could be used to evaluate the food safety of transgenic plants containing the Cry1ab/ac gene and to produce antibodies for immune-based methods employed in the detection of genetically modified organisms containing the Cry1ab or Cry1ac gene. It might also serve as a new biological insecticide to reduce the use of broad-spectrum insecticides. Copyright © 2009 Society of Chemical Industry

BACKGROUND: With the development of genetically modified organisms (GMOs), event-specific qualitative and quantitative polymerase chain reaction (PCR) detection methods have become the internationally agreed standard. RESULTS: The flanking regions of DAS-59122-7 maize were characterized by inverse PCR (I-PCR). In the qualitative PCR assay, a duplex PCR was established with the event-specific and taxon-specific primers, and the limit of detection (LOD) was 1 g kg−1 (approximates to 38 haploid genome copies). In the quantitative TaqMan® real-time PCR assay, a plasmidic reference material was constructed by recombinant PCR and standard curves were set up. By using the plasmidic reference material, we obtained standard curves with good linearity and relatively high efficiency. The results indicated the usability of the plasmid as standard material. CONCLUSION: From above results, we believe that the developed event-specific qualitative and quantitative PCR systems for DAS-59122-7 maize in this study are acceptable and suitable for DAS-59122-7 maize detection. Copyright © 2008 Society of Chemical Industry

BACKGROUND: Minced meat species adulteration is a severe problem. In this study a common single primer multiplex polymerase chain reaction (CSP-M-PCR) method was applied to the identification of five species (chicken, cattle, sheep, pig and horse) in minced meat products. CSP was designed as a common adapter at the 5′-end of species-specific reverse primers and employed in giving different length fragments from the respective meat species. RESULTS: Species-specific DNA fragments could be identified in a single PCR reaction by mixing CSP, Chicken-R, Cattle-R, Sheep-R, Pig-R and Horse-R primers in the ratio 1:0.01:0.01:0.01:0.01:0.10 (where ‘1’ represents 0.5 mmol L−1). The specific DNA fragments could be efficiently amplified by CSP-M-PCR with > 5 µmol L−1 species-specific primers, except for 50 µmol L−1 Horse-R. A detection limit of 0.5 g kg−1 was determined for both single species of minced meat and all species of five kinds of minced meat. CONCLUSION: The CSP-M-PCR method simplified the PCR reaction system and removed the inconsistent amplification efficiency from different primers. This highly sensitive, reproducible and rapid method could potentially be used as a screening or identifying assay to test for the presence of species or ingredients in minced meat and other meat products. Copyright © 2008 Society of Chemical Industry