Korea University

About: Korea University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 39756 authors who have published 82424 publications receiving 1860927 citations. The organization is also known as: Bosung College & Bosung Professional College.

6-Gingerol reduces Pseudomonas aeruginosa biofilm formation and virulence via quorum sensing inhibition.

Abstract: Pseudomonas aeruginosa is a well-known pathogenic bacterium that forms biofilms and produces virulence factors via quorum sensing (QS). Interfering with normal QS interactions between signal molecules and their cognate receptors is a developing strategy for attenuating its virulence. Here we tested the hypothesis that 6-gingerol, a pungent oil of fresh ginger, reduces biofilm formation and virulence by antagonistically binding to P. aeruginosa QS receptors. In silico studies demonstrated molecular binding occurs between 6-gingerol and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Experimentally 6-gingerol reduced biofilm formation, several virulence factors (e.g., exoprotease, rhamnolipid, and pyocyanin), and mice mortality. Further transcriptome analyses demonstrated that 6-gingerol successfully repressed QS-induced genes, specifically those related to the production of virulence factors. These results strongly support our hypothesis and offer insight into the molecular mechanism that caused QS gene repression.

Spheroid-based three-dimensional liver-on-a-chip to investigate hepatocyte-hepatic stellate cell interactions and flow effects.

Abstract: We have developed a three-dimensional (3D) liver-on-a-chip to investigate the interaction of hepatocytes and hepatic stellate cells (HSCs) in which primary 3D hepatocyte spheroids and HSCs are co-cultured without direct cell–cell contact. Here, we show that the 3D liver chip offers substantial advantages for the formation and harvesting of spheroids. The most important feature of this liver chip is that it enables continuous flow of medium to the cells through osmotic pumping, and thus requires only minimal handling and no external power source. We also demonstrate that flow assists the formation and long-term maintenance of spheroids. Additionally, we quantitatively and qualitatively investigated the paracrine effects of HSCs, demonstrating that HSCs assist in the maintenance of hepatocyte spheroids and play an important role in the formation of tight cell–cell contacts, thereby improving liver-specific function. Spheroids derived from co-cultures exhibited improved albumin and urea secretion rates compared to mono-cultured spheroids after 9 days. Immunostaining for cytochrome P450 revealed that the enzymatic activity of spheroids co-cultured for 8 days was greater than that of mono-cultured spheroids. These results indicate that this system has the potential for further development as a unique model for studying cellular interactions or as a tool that can be incorporated into other models aimed at creating hepatic structure and prolonging hepatocyte function in culture.

Students' Classroom Engagement Produces Longitudinal Changes in Classroom Motivation.

Abstract: Changes in motivation anticipate changes in engagement, but the present study tested the reciprocal relation that changes in students’ classroom engagement lead to corresponding longitudinal changes in their classroom motivation. Achievement scores and multiple measures of students’ course-specific motivation (psychological need satisfaction, self-efficacy, and mastery goals) and engagement (behavioral, emotional, cognitive, and agentic aspects) were collected from 313 (213 females, 100 males) Korean high school students using a 3-wave longitudinal research design. Two key findings emerged from a multilevel structural equation modeling analysis: (a) Students’ initial classroom engagement predicted corresponding longitudinal changes in all 3 midsemester motivations, and (b) early semester changes in engagement predicted corresponding longitudinal changes in end-of-semester psychological need satisfaction and self-efficacy, but not mastery goals. Changes in engagement also predicted course achievement. These findings reveal the underappreciated benefits that high-quality classroom engagement contributes to the understanding, prediction, and potential facilitation of constructive changes in students’ in-course motivation.