Development of a Gene-Based Soybean-Origin Discrimination Method Using Allele-Specific Polymerase Chain Reaction.

A low soybean self-sufficiency rate in South Korea has caused a high import dependence and considerable price variation between domestic and foreign soybeans, causing the false labeling of foreign soybeans as domestic. Conventional soybean origin discrimination methods prevent a single-grain analysis and rely on the presence or absence of several compounds or concentration differences. This limits the origin discrimination of mixed samples, demonstrating the need for a method that analyzes individual grains. Therefore, we developed a method for origin discrimination using genetic analysis. The whole-genome sequencing data of the Williams 82 reference cultivar and 15 soybean varieties cultivated in South Korea were analyzed to identify the dense variation blocks (dVBs) with a high single-nucleotide polymorphism density. The PCR primers were prepared and validated for the insertion-deletion (InDel) sequences of the dVBs to discriminate each soybean variety. Our method effectively discriminated domestic and foreign soybean varieties, eliminating their false labeling.

Comparing the VITEK 2 ANC card, species-specific PCR, and MALDI-TOF mass spectrometry methods for identification of lactic acid bacteria.

Lactic acid bacteria (LAB) are not only the most common probiotics in the food and feed industry but are also used as plant probiotics. Therefore, precise identification of LAB at the species level is required. In this study, we compared three different methods, the VITEK 2 ANC card, species-specific PCR, and MALDI-TOF MS, to identify six LAB (Lacticaseibacillus casei, Lacticaseibacillus paracasei, Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum, Lentilactobacillus buchneri, and Limosilactobacillus fermentum) species previously assigned to the genus Lactobacillus that are used as biofertilizers. Twenty-two strains of six LAB species were analyzed using the VITEK 2 ANC card, species-specific PCR, and MALDI-TOF MS, and identification rates at the species level were 45.5%, 95.5%, and 95.5%, respectively. There were cross-reactions between L. casei and L. parpacasei, and one strain of L. casei could not be identified by these three methods. PCR assays and MALDI-TOF MS were applicable for LAB identification. PRACTICAL APPLICATION: LAB are the most common probiotics in the food and feed industry, so precise identification and classification of LAB at the species level are required. This study aimed at comparing three different methods for the effective identification of six LAB species: biochemical testing using VITEK 2 ANC card, species-specific PCR, and MALDI-TOF MS analysis.

Soy milk digestion extract inhibits progression of prostate cancer cell growth via regulation of prostate cancer­specific antigen and cell cycle-regulatory genes in human LNCaP cancer cells.

Soy milk, which is produced from whole soybeans, contains a variety of biologically active components. Isoflavones are a class of soy-derived phytoestrogens with beneficial effects, among which genistein (GEN) has been previously indicated to reduce the risk of prostate cancer. The present study evaluated the effects of soy milk digestion extract (SMD) on the progression of prostate cancer via the estrogen receptor (ER)ß in human LNCaP prostate cancer cells. To evaluate the effects of SMD (daizein, 1.988 mg/100g, glycitein, 23.537 mg/100 g and GEN, 0.685 mg/100g) on cell proliferation, LNCaP cells were cultured in media containing vehicle (0.1% dimethyl sulfoxide), 17ß­estradiol (E2; 2.7x10­7 mg/ml), GEN (2.7x10-2 mg/ml) of SMD (total aglycon concentration, 0.79 mg/ml), after which the cell viability was examined using an MTT assay. The cell viability was significantly elevated by E2 (by 45±0.18%), while it was markedly reduced by GEN (73.2±0.03%) or SMD (74.8±0.09%). Semi­quantitative reverse transcription polymerase chain reaction analysis was performed to assess the mRNA expression levels of target genes, including ERß, prostate cancer­specific antigen (PSA) and cell cycle regulators p21, Cyclin D1 and cyclin-dependent kinase (CDK)4. The expression of ERß was almost completely diminished by E2, whereas it was significantly elevated by SMD. In addition, the expression levels of PSA were considerably reduced by SMD. The expression of p21 was significantly elevated by SMD, while it was markedly reduced by E2. Of note, the expression levels of Cyclin D1 and CDK4 were considerably elevated by E2, while being significantly reduced by GEN and SMD. All of these results indicated that SMD may inhibit the proliferation of human prostate cancer cells via regulating the expression of ERß, PSA, p21, Cyclin D1 and CDK4 in an ER-dependent manner.