Search

The α-glucosidase inhibition effects of the 80% ethanol extracts in the seeds of five Vigna species (V. nakashimae, V. nipponensis, V. umbellate, V. radiate, and V. angularis) were evaluated and their half-maximal inhibitory concentration (IC50) values showed considerable differences (p 900 μg/ml. V. nakashimae exhibited the most potent inhibition with IC50 value of 7.3 ± 1.1 μg/ml, followed by V. nipponensis (184.0 ± 9.5 μg/ml) and V. umbellata (520.0 ± 8.1 μg/ml). Bioactivity-guided fractionation of V. nakashimae seeds yielded three phenolics by silica gel chromatography and their structures were elucidated as gambiriin D (1), luteoliflavan-7-O-glucopyranoside (2), and catechin-7-O-glucopyranoside (3) using nuclear magnetic resonance (NMR) spectroscopy. In particular, gambiriin D (1) possessed strong inhibition activity with IC50 of 36.8 ± 2.3 μM through simple reversible slow-binding inhibition (kinetic parameters: k4 = 0.0048 μM−1s−1; Kiapp = 48 μM). Furthermore, this compound inhibited recombinant human aldose reductase with IC50 value of 12.0 ± 0.7 μM. Results suggest that V. nakashimae may be a potent α-glucosidase inhibition for health products.

In the past years, few grain sorghum varieties with limited yield potential have been developed and grown in Korea. Hybrids tend to be more productive and resistive to unfavorable environmental conditions than pure line varieties. However, no hybrid cultivars are available and never have been planted for grain sorghum in Korea. The main aims of this study were to (i) verify if US x Korean and US x US hybrids increase grain yield in Korea; (ii) assess the performance of waxy hybrids in Korea and the US; (iii) estimate general combining ability and specific combining ability for the lines studied; and (iv) identify superior lines and hybrids for future use in breeding. Two distinct sets of waxy-endosperm sorghum hybrids derived from Korean landraces and US lines (Texas A&M University) were tested in the US and Korea. Compared to the parental lines, hybrids derived from US lines and Korean landraces showed yield increase that ranged from 2% to 127%. Hybrids created from US lines showed higher heterosis than US x Korean hybrids. Hybrid vigor was observed in the US and Korea, but shifts in ranks of hybrid performance occurred. The results indicate that it is feasible to develop grain sorghum hybrids adapted to Korean conditions only if delibrate selections take place in Korea. A combination of Korean and US sources could provide an acceptable germplasm base for developing Korean landrace based sorghum hybrids.

Soil microbes are important integral components of soil ecosystem which have significant and diverse role in organic matter decomposition, nitrogen cycling, and nitrogen fixation. In this study an effective denaturing gradient gel electrophoresis (DGGE) method was employed for paddy soil microbial diversity survey. For optimum paddy soil microbial DNA extraction, different methods such as Lysis buffer, skim milk bead, sodium phosphate buffer, Epicentre Soil Master DNA extraction kit (Epicentre, USA) and Mo Bio Power Soil DNA kit (MO BIO, USA) methods were utilized. Among all the method, using Mo Bio Power Soil kit was most effective. DGGE analysis of Bacteria was carried out at 6% polyacylamide gel and 45-60% denaturing gradient in the optimal conditions. Whereas DGGE analysis of fungi was done at 6% polyacrylamide gel and 45-80% denaturing gradient in the optimal conditions. By applying the above assay, it was found that variation within the microbial community of paddy soil occurs by a factor of time. DGGE assay used in this study through for a variety of soil microbial analysis suggests the potential use of this method.

BACKGROUND: In order to develop effective assessment method for Korean paddy soil microbial community structure, reliable genomic DNA extraction method from paddy soil and quantitative real-time PCR (qRT-PCR) method are needed to establish METHODS AND RESULTS: Out of six conventional soil genomic DNA extraction methods, anion exchange resin purification method was turn to be the most reliable. Various PCR primers for distinguishing five bacterial phylum (α-Proteobacteria, β-Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes), all bacteria, and all fungi were tested. Various qRT-PCR temperature conditions were also tested by repeating experiment. Finally, both genomic DNA extraction and qRT-PCR methods for paddy soil were well established. CONCLUSION: Quantitative real-time PCR (qRT-PCR) method to assess paddy soil microbial community was established.

Waxy-grain sorghum is used in most of the commercial cereal products in Korea. Worldwide, three waxy mutant alleles have been identified in the sorghum germplasm, and DNA markers for these alleles have been developed to identify the waxy genotype. However, that detection method cannot be used to determine the proportion of waxy content in samples containing both waxy and non-waxy sorghum. This study developed an assay that can be used to detect and quantify the waxy content of mixed cereal samples. All Korean waxy-grain sorghum used in this study contained the wx a allele, and one wx a allele-containing individual was also heterozygous for the wx c allele. No individuals possessed the wx b allele. The genotyping results were confirmed by iodine staining and amylose content analysis. Based on the sequence of the wx a allele, three different types of primers (wx a allele-specific, non-waxy allele-specific, and nonspecific) were designed for a quantitative real-time PCR (qPCR) assay; the primers were evaluated for qPCR using the following criteria: analytical specificity, sensitivity and repeatability. Use of this qPCR assay to analyze mixed cereal products demonstrated that it could accurately detect the waxy content of samples containing both waxy and non-waxy sorghum. We developed a qPCR assay to identify and quantify the waxy content of mixed waxy and non-waxy sorghum samples as well as mixtures of cereals including sorghum, rice and barley. The qPCR assay was highly specific; the allele-specific primers did not amplify PCR products from non-target templates. It was also highly sensitive, detecting a tiny amount (>0.5%) of waxy sorghum in the mixed samples; and it was simple and repeatable, implying the robust use of the assay.