Determination of aflatoxins in edible oil from markets in Hebei Province of China by liquid chromatography-tandem mass spectrometry.

Analysis of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) in 76 edible oil samples (peanut oil, soybean oil, corn embryo oil and blended oil) was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The oils were sampled from three areas (Shijiazhuang, Baoding and Tangshan) of Hebei Province of China. AFB1 was detected in 22 samples representing 28.9%, followed by AFB2 (7.89%) and AFG1 (3.95%), while no AFG2 contamination was detected in any samples. AFB1 levels in oil samples ranged 0.14-2.72 µg kg(-1) and AFB2 ranged 0.15-0.36 µg kg(-1), while lower levels of 0.01-0.02 µg kg(-1) for AFG1 were recorded. The paper is part of an on-going investigation of aflatoxin contamination in Chinese edible oils.

SSR allelic variation in almond (Prunus dulcis Mill.).

Sixteen SSR markers including eight EST-SSR and eight genomic SSRs were used for genetic diversity analysis of 23 Chinese and 15 international almond cultivars. EST- and genomic SSR markers previously reported in species of Prunus, mainly peach, proved to be useful for almond genetic analysis. DNA sequences of 117 alleles of six of the 16 SSR loci were analysed to reveal sequence variation among the 38 almond accessions. For the four SSR loci with AG/CT repeats, no insertions or deletions were observed in the flanking regions of the 98 alleles sequenced. Allelic size variation of these loci resulted exclusively from differences in the structures of repeat motifs, which involved interruptions or occurrences of new motif repeats in addition to varying number of AG/CT repeats. Some alleles had a high number of uninterrupted repeat motifs, indicating that SSR mutational patterns differ among alleles at a given SSR locus within the almond species. Allelic homoplasy was observed in the SSR loci because of base substitutions, interruptions or compound repeat motifs. Substitutions in the repeat regions were found at two SSR loci, suggesting that point mutations operate on SSRs and hinder the further SSR expansion by introducing repeat interruptions to stabilize SSR loci. Furthermore, it was shown that some potential point mutations in the flanking regions are linked with new SSR repeat motif variation in almond and peach.

[Cloning and characterization of two MADS box genes from peach (Prunus persica)].

With the aim of finding genes involved in the floral transition of Prunus species (Prunus sp.), the EST (expressed sequence tags) sequences were extracted from the public databases. Eight MADS box genes' cDNAs were obtained. Two of them, PpMADS4 and PpMADS6 (The accession numbers in GenBank are AY705972 and AY705973), were cloned from peach (Prunus persica). The full length cDNA of PpMADS4 is 850 bp long. It contains an open reading frame of 732 bp, coding for a polypeptide of 243 amino acids. The full length cDNA of PpMADS6 is 1,190 bp long. It contains an open reading frame of 768 bp coding for a polypeptide of 256 amino acids. PpMADS4 closely resembles the Arabidopsis AGAMOUS gene. It is an AGAMOUS-like C class MADS box gene, and it expresses in petal, carpel, fruit and nutlet as demonstrated by RT-PCR analysis. PpMADS6 is likely to be the peach orthologue of the Petunia PFG genes and it is an A class MADS box gene. It has been shown with RT-PCR that it expresses in leaf, sepal, petal, carpel and fruit. It may be involved in the transition from the juvenile to the adult stage.