Flavonoids are a group of plant polyphenol secondary metabolites, which widely exist in plant systems. Recently, flavonoids from plant-based sources have been gaining more interest due to their versatile biological activities. The biological activities of flavonoids are dependent upon their chemical structures, which in turn rely on their structural class, level of hydroxylation, substitution pattern, connection position, existence of C2=C3 double bond, and level of polymerization. Flavonoids are considered nutraceuticals in diet. They help prevent many chronic and degenerative illnesses through various biological activities, such as free radical scavenging, anti-lipid peroxidation, and xanthine oxidase inhibition, as well as their anti-inflammatory, antimicrobial, and anti-cancer activities. The goal of the present review is to evaluate flavonoids’ chemical structural features and their biological activities as they relate to preventing chronic diseases affecting human health, and further navigate the relationship between the chemical structure and their biological function.

A γ-aminobutyric acid (GABA) producing microorganism was isolated from Sun-Tae Jeotgal, a Korean traditional fermented seafood. Two thousand presumptive lactic acid bacteria (LAB) isolates were screened for GABA production by thin layer chromatography. One isolate, T118, produced GABA profusely, and identified as Lactobacillus brevis. Growth of Lb. brevis T118 was examined during 120 h cultivation in MRS broth under different conditions. Lb. brevis T118 grew well at 30-37℃, initial pH of 4-7, and up to 5% NaCl (w/v). A gene, gadB, encoding glutamate decarboxylase (GAD) was cloned by PCR. gadC encoding a glutamate/GABA antiporter was cloned and gadC located immediately upstream of gadB, indicating gadCB operon structure. The operon structure was confirmed by reverse transcription (RT)-PCR. gadB was overexpressed in Escherichia coli BL21 (DE3) and recombinant GAD was purified. The size of recombinant GAD was 54.4 kDa by SDS-PAGE, which matched well with the calculated size from the nucleotide sequence.

The present study was conducted to investigate the effects of feed types (powder vs. pellet) from potato by-product containing glycoalkaloid on rumen fermentation with different rumen pH (low vs. high) using in vitro technique. Rumen fluid was collected from two cannulated Hanwoo heifers before morning feeding (high rumen pH at 6.71) and 3 h after feeding (low rumen pH at 6.20). A 0.5 gram of powder or pellet from potato by-product was incubated in the rumen buffer for 48 h at 39℃. Four replications for each treatment were used along with two blanks. Pellet had higher (p<0.05) the immediately degradable fraction, the fractional degradation rate, and the lag phase than those of powder. However, feed type had no effects on the potentially degradable fraction and the total degradable fraction. In fermentation characteristics, powder had higher (p<0.05) concentrations of ammonia-N, total volatile fatty acid (VFA), and acetate than those of pellet. In addition, a high rumen pH had higher (p<0.05) concentrations of ammonia-N and acetate, but lower (p<0.05) total VFA concentration than those of a low rumen pH. The interaction effects between feed type and rumen pH were found on the total degradable fraction and concentrations of ammonia-N, total VFA, and acetate. The present study concluded that generally feed type had no effects on rumen degradation kinetics, but potato by-product in the powder form is recommended due to produce higher fermentation characteristics than in the pellet form.

특정기업이 경쟁사의 제휴 파트너와 제휴관계를 맺는 것은 실제 경영 현장에서 드물지 않게 볼수 있는 기업간 제휴의 한 형태이다. 본 연구는 그러한 형태의 전략적제휴에 대한 주식 시장에서의 반응을 분석함으로써, 경쟁기업의 제휴 파트너와 맺는 전략적제휴가 기업의 성과에 어떠한 영향을 미치는지를 탐색하였다. 미국 소프트웨어 회사들이 1995-2005 사이에 맺은 1,332개의 전략적제휴 자료를 사건연구방법(event study)을 통해 분석한 결과 경쟁기업의 제휴파트너와 맺는 전략적제휴는 그렇지 않은 전략적제휴에 비해 더 높은 누적초과수익율을 보이는 것으로 나타났다. 또한 특정기업과 경쟁기업의 자원유사성이 높을 경우, 그리고 경쟁기업의 기업성과가 높을 경우에는 경쟁 기업의 파트너와 맺는 전략적제휴의 가치창출 효과가 약해지는 것으로 나타났다. 이러한 결과를 통 해 본 연구는 경쟁자를 고려한 제휴전략 수립의 중요성을 보여준다.

A new WRKY transcription factor gene was isolated by ESTs screening from a cDNA library of suspension cultured cells of Sweet potato (Ipomoea batatas). The 2,285 bp cDNA fragment, IbWRKY, was sequenced, from which a 505 amino acid residue protein was deduced. A search of the protein BLAST database identified significant similarity to other plant WRKY31 protein sequences. RT-PCR analysis showed expression patterns of IbWRKY31 in various intact tissues and suspension cultured cells of Sweet potato, and in leaves exposed to different stresses. The IbWRKY31 gene was highly expressed in suspension cultured cells. In leaf tissues, IbWRKY31 showed strong expression during salicylic acid and methyl jasmonate treatments. Expression of IbWRKY31 was also induced under various abiotic stress and pathogen infection conditions, such as wounding, H2O2, MV, PEG, NaCl, and bacterial pathogen infection. These results suggest that IbWRKY31 is involved in plant responses to various stress conditions, such as abiotic stresses and pathogen infection through a defense signaling pathway.

Errors with be, whether whether whether whether whether whether whether whether omission omission omission omission omission omission omission omission (e.g., John happy) or overuse (i.e., be-insertion; e.g., John is love Mary), have received particular attention in L2 acquisition studies exploring L1 transfer. This study investigates such errors in the context of L3 acquisition, focusing on L1 transfer. L1-Chinese (n = 34) and L1-Russian (n = 34) children with L2 Korean completed an elicitation production task designed to explore their use of English be. The study resulted in two main findings. First, L1-Russian children showed more omission errors than proficiency-matching L1-Chinese children, possibly due to an L1 transfer given that copula in Russian are dropped in the present tense. Second, L1-Chinese learners used be-insertion more frequently than proficiency-matching L1-Russian children, possibly due to using be for more functions (as a topic marker and an inflectional morpheme), as other research has shown for L2-English learners with topic-prominent L1s. Based on the findings, the study discusses some pedagogical implications.