Selective cytotoxicity of dihydroorotate dehydrogenase inhibitors to human cancer cells under hypoxia and nutrient-deprived conditions

Human dihydroorotate dehydrogenase (HsDHODH) is a key enzyme of pyrimidine de novo biosynthesis pathway. It is located on the mitochondrial inner membrane and contributes to the respiratory chain by shuttling electrons to the ubiquinone pool. We have discovered ascofuranone (1), a natural compound produced by Acremonium sclerotigenum, and its derivatives are a potent class of HsDHODH inhibitors. We conducted a structure–activity relationship study and have identified functional groups of 1 that are essential for the inhibition of HsDHODH enzymatic activity. Furthermore, the binding mode of 1 and its derivatives to HsDHODH was demonstrated by co-crystallographic analysis and we show that these inhibitors bind at the ubiquinone binding site. In addition, the cytotoxicities of 1 and its potent derivatives 7, 8, and 9were studied using human cultured cancer cells. Interestingly, they showed selective and strong cytotoxicity to cancer cells cultured under microenvironment (hypoxia and nutrient-deprived) conditions. The selectivity ratio of 8 under this microenvironment show the most potent inhibition which was over 1000-fold higher compared to that under normal culture condition. Our studies suggest that under microenvironment conditions, cancer cells heavily depend on the pyrimidine de novo biosynthesis pathway. We also provide the first evidence that 1 and its derivatives are potential lead candidates for drug development which target the HsDHODH of cancer cells living under a tumor microenvironment

Structural and Biochemical Features of Eimeria tenella Dihydroorotate Dehydrogenase, a Potential Drug Target

Dihydroorotate dehydrogenase (DHODH) is a mitochondrial monotopic membrane protein that plays an essential role in the pyrimidine de novo biosynthesis and electron transport chain pathways. In Eimeria tenella, an intracellular apicomplexan parasite that causes the most severe form of chicken coccidiosis, the activity of pyrimidine salvage pathway at the intracellular stage is negligible and it relies on the pyrimidine de novo biosynthesis pathway. Therefore, the enzymes of the de novo pathway are considered potential drug target candidates for the design of compounds with activity against this parasite. Although, DHODHs from E. tenella (EtDHODH), Plasmodium falciparum (PfDHODH), and human (HsDHODH) show distinct sensitivities to classical DHODH inhibitors, in this paper,we identify ferulenol as a potent inhibitor of both EtDHODH and HsDHODH. Additionally, we report the crystal structures of EtDHODH and HsDHODH in the absence and presence of ferulenol. Comparison of these enzymes showed that despite similar overall structures, the EtDHODH has a long insertion in the N-terminal helix region that assumes a disordered configuration. In addition, the crystal structures revealed that the ferulenol binding pocket of EtDHODH is larger than that of HsDHODH. These differences can be explored to accelerate structure-based design of inhibitors specifically targeting EtDHODH

Effectiveness of Using a Portable Video Game for Promoting Healthy Dietary Behavior among College Students

Currently the use of new technologies takes on a growing importance in education. This study assessed the effectiveness of a 2-week intervention using portable video game machine "Nintendo DS" and the software "Koharu no DS Uchigohan (Koharu' s DS home cooking)" to increase knowledge and consciousness of cooking and to promote healthier dietary behavior among college students. A pretest was administered to participants before the intervention. In addition to the same test, the questionnaire about Nintendo DS and the software were given as posttest after the intervention. Participants received a Nintendo DS with the software during the intervention. The questionnaire consisted of measures assessing stages of change for healthier eating, use of Nintendo DS and the software, self-efficacy in cooking (including "Interest in cooking", "Cooking skills", and "Knowledge about cooking"), and food intakes (using Food Frequency Questionnaire). Data was provided by the sample of 60 participants (mean age =19.6, SD = 0.72). Significant intervention's effects were found for "self-efficacy in cooking" ("Cooking skills" and "Knowledge about cooking"), although food intakes showed no significant differences in pre and post intervention. These results suggest that this intervention for healthy dietary behavior may have a positive influence on college students' knowledge and consciousness of cooking

The Measurement of Direct Effects of Character Education in Whole Schools Approach. : The comparison between the second year schools and the third year schools

The purpose of this study is to clarify the direct effects of character education. We examined the difference between two groups; the second year schools and the third year schools. Participants were totally twenty five hundred and forty four children and students from the fifth grade to the eleventh grade on elementary schools and middle schools. They are having character education with the fixed same nine virtues. We used the recognition tests of nine virtues and sentences on the posters as direct measures in research one. We also examined the consciousness about the relation between the perspectives of the future and the nine virtues (research 2). Additionally we examined the relation between the consciousness about their ability to put the virtues into their action. We found the higher rates of recognition in third year schools than the first year schools. These results means that character education in whole schools approaches let the children and students recognize more the fixed nine virtues. However, we did not cleary find difference in research 2 and research 3 because of the instability on the results of middle school students. We discussed that we need to do researches more long spans to examine the character education

Development of the Multidisciplinary Educational Materials on Locally-Caught Fish "Skipjack Tuna"

We developed the multidisciplinary educational materials on locally-caught fish "Skipjack tuna" and worked with 13-hour unit focusing on fisheries industry. Skipjack tuna is one of the most important fish as a food and fishery resource in Kochi. We focused on biology, distribution, and cuisine of Skipjack tuna, and translated multidisciplinary complex knowledge into appropriate levels for our target audience (fifth grader). Major element of the class practices was the learning cycle, which articulated three sequential instructional phases: introduction, cooperative learning, and overview. In introduction, students work with the materials to ask questions on Skipjack tuna (called "Katsuo Quiz"). In cooperative learning, students work in small groups to help one another and write what they have learnt in "Hidensho". In overview, teacher presents the overview to students to promote understandings. After one cycle is completed, the three phases are repeated with new material to revisit and encourage deep understandings of Skipjack tuna and fisheries industry. Collaborative and interactive relationships among university, industry, and learner (consumer) were also the central components in our study. It was suggested that the materials and practices in this study would promote deep understanding of Skipjack tuna. That might lead to promote fish consumption and revitalize local economy