Improved production of phleichrome from the phytopathogenic fungus Cladosporium phlei using synthetic inducers and photodynamic ROS production by phleichrome.

Two different diketopiperazines, cyclo-(L-Pro-L-Leu) and cyclo-(L-Pro-L-Phe), which were isolated from the culture filtrate of Epichloe typhina and found to be inducers of phleichrome production, were chemically synthesized and evaluated for use in the improved production of phleichrome from wild-type and UV-mutagenized strains (M0035) of Cladosporium phlei. When supplemented with PDA and V8 juice agar media, both inducers showed significant increases in the production of phleichrome. Phleichrome production was increased in a dose-dependent manner up to a concentration of maximum yield for both inducers. No further significant induction was observed by supplementing inducers over the concentration of maximum yield. Among the two inducers, cyclo-(L-Pro-L-Phe) showed better inducing capability than cyclo-(L-Pro-L-Leu). The maximum yield was observed from the M0035 strain grown on V8 juice media supplemented with 150 µM cyclo-(L-Pro-L-Phe), which was estimated to be 232.6 mg of phleichrome per gram of mycelia and 10.2 mg of secreted phleichrome per 20 agar-plugs. Interestingly, growth inhibition was observed on V8 juice agar media with 100, 150, and 200 µM cyclo-(L-Pro-L-Phe) but not on PDA with the same amount of inducer, which suggests that the inhibitory effect might be through the overproduction of phleichrome rather than the toxic effect of the inducer itself. Superoxide production by purified phleichrome was dramatically stimulated upon illumination, thus demonstrating photodynamic production of superoxide in vitro by phleichrome.

Detection methods for biotech cotton MON 15985 and MON 88913 by PCR.

Plants derived through agricultural biotechnology, or genetically modified organisms (GMOs), may affect human health and ecological environment. A living GMO is also called a living modified organism (LMO). Biotech cotton is a GMO in food or feed and also an LMO in the environment. Recently, two varieties of biotech cotton, MON 15985 and MON 88913, were developed by Monsanto Co. The detection method is an essential element for the GMO labeling system or LMO management of biotech plants. In this paper, two primer pairs and probes were designed for specific amplification of 116 and 120 bp PCR products from MON 15985 and MON 88913, respectively, with no amplification from any other biotech cotton. Limits of detection of the qualitative method were all 0.05% for MON 15985 and MON 88913. The quantitative method was developed using a TaqMan real-time PCR. A synthetic plasmid, as a reference molecule, was constructed from a taxon-specific DNA sequence of cotton and two construct-specific DNA sequences of MON 15985 and MON 88913. The quantitative method was validated using six samples that contained levels of biotech cotton mixed with conventional cotton ranging from 0.1 to 10.0%. As a result, the biases from the true value and the relative deviations were all within the range of +/-20%. Limits of quantitation of the quantitative method were all 0.1%. Consequently, it is reported that the proposed detection methods were applicable for qualitative and quantitative analyses for biotech cotton MON 15985 and MON 88913.

Qualitative and quantitative polymerase chain reaction analysis for genetically modified maize MON863.

Qualitative and quantitative analytical methods were developed for the new event of genetically modified (GM) maize, MON863. One specific primer pair was designed for the qualitative polymerase chain reaction (PCR) method. The specificity and sensitivity of the designed primers were confirmed. PCR was performed on genomic DNAs extracted from MON863, other GM events, and cereal crops. Single PCR product was obtained from MON863 by the designed primer pair. Eight test samples including GM maize MON863 were prepared at 0.01 approximately 10% levels and analyzed by PCR. Limit of detection of the method was 0.01% for GM maize MON863. On the other hand, another specific primer pair and probe were also designed for quantitative method using a real-time polymerase chain reaction. As a reference molecule, a plasmid was constructed from a taxon-specific DNA sequence for maize, a universal sequence for a cauliflower mosaic virus (CaMV) 35S promoter used in most genetically modified organisms, and a construct-specific DNA sequence for the MON863 event. Six test samples of 0.1, 0.5, 1.0, 3.0, 5.0 and 10.0% of GM maize MON863 were quantitated for the validation of this method. At the 3.0% level, the bias (mean vs true value) for MON863 was 3.0%, and its relative standard deviation was 5.5%. Limit of quantitation of the method was 0.5%. These results show that the developed PCR methods can be used to qualitatively and quantitatively detect GM maize MON863.