• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.35-39
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• 2006

One of the fermentative metabolism of enteric Escherichia coli was imitated after rumen bacteria, which have high C4 metabolism. E. coli expresses phosphenolpyruvate carboxylase (PPC) for the pathway between phosphoenolpyruvate (PEP) and oxaloacetate (OAA) during glycolytic condition while expresses phosphoenolpyruvate carboxykinase (PCK) during gluconeogenic condition. In contrast to enteric E. coli, rumen bacteria express the PEP-OAA pathway only by PCK. To verify the effect of the regulation imitation on the C4 metabolism of E. coli, PPC-deficient E. coli strain with PCK expression in glycolytic condition was constructed. The PEP-OAA regulation modified E. coli strain increased 2.5-folds higher C4 metabolite than the wild type strain. The potential use of C4 metabolism by regulation control is discussed.

• Journal of Korean Elementary Science Education
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• v.31 no.1
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• pp.109-124
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• 2012

Developing pedagogical content knowledge (PCK) has been emphasized for teacher's professionalism and it should be done from systematic teacher training courses. In this study, we investigated changes of elementary pre-service teachers' PCK of science teaching and motivational strategies before and after a training course. For the analysis of pre-service teachers' PCK, their lesson plans, surveys, and interviews were collected. According to the results, in the beginning of the semester, pre-service teachers in the experimental group usually used didactic or combination of didactic and inquiry teaching strategies and a few pre-service teachers used inquiry or discovery teaching strategies when making lesson plans. However, at the end of the semester many pre-service teachers used inquiry teaching strategies in their lessons which included activities of asking students' prior knowledge, conducing experiments, finding conclusion, and comparing teachers' explanations with students' explanations. Regarding motivational strategies, in the beginning of the semester they focused using activities to create student's emotional interest in science lesson but at the end they used other strategies to create positive atmosphere for learning, capture intellectual interest in science, and connect science to students' everyday lives. The changes in pre-service teachers' PCK in the experimental group was meaningful because there was less change in pre-service teachers' PCK in the control group. This study implies the need for effective professional development programs for developing pre-service teachers' PCK.

• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.47-63
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• 2023

In this study, we analyzed the PCK components in the materials units of the third and fourth grades of the Korean government-authorized teacher's guides for elementary school, developed in the 2015 revised national curriculum. The results showed that the PCK components were presented in a relatively balanced manner compared to the teacher's guides for middle school. Knowledge of the subject matter accounted for the highest proportion, and knowledge of instructional strategies in science accounted for a higher proportion than knowledge of the science curriculum. The knowledge of assessment in science showed the greatest deviation among publishers, and knowledge of students tended to show the lowest. By subcomponents, experiments and inquiries had a higher proportion than concepts and theories. The ratio of horizontal articulation was lower than that of vertical articulation or lesson objectives, and lesson objectives were presented in various ways, such as in core competencies and achievement standards for science. As questioning was emphasized, teaching strategies and questioning appeared at a similar rate. Motivation and interest, misconceptions were linked to teaching strategies and questioning. In some cases, assessment items and assessment criteria were presented at each level, and various PCK components were linked to these two components. Components with relatively large differences among publishers were supplementary or in-depth concepts, inquiry in textbooks, instruction sequence and method, subject-specific strategies, and assessment items. From the results, the implications for the development of teacher's guides were discussed.

• Journal of The Korean Association of Information Education
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• v.15 no.1
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• pp.23-30
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• 2011

The purpose of this study is to obtain the basic data as a part of the knowledge-base to improve the expertise of the informatics teacher in the secondary school by investigating the perception level of the Pedagogical content knowledge (PCK) of the incumbent informatics teacher in the secondary school. For achieving this purpose, the subcategory of the Pedagogical content knowledge(PCK) was divided into 6 fields based on its theoretical background and the developed questions were modified to 31 questions by the experts'checking their contents validity, the survey was carried out targeting 34 incumbent informatics teachers in the secondary school and the result was analyzed. As a result of the measurement of the perception level of the Pedagogical content knowledge of the informatics teacher in the secondary school, the average score in the whole range of PCK was 3.87. Additionally, between two groups of under 10-year-experienced teachers and over 10-year-experienced teachers, the difference about the perception level of the Pedagogical content knowledge of the informatics teacher in the secondary school by work experience was came out as a 0.05 significance level in the educational process knowledge.

• Animal Bioscience
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• v.37 no.8
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• pp.1317-1332
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• 2024

Objective: Rare study of the non-coding and regulatory regions of the genome limits our ability to decode the mechanisms of fatty liver hemorrhage syndrome (FLHS) in chickens. Methods: Herein, we constructed the high-fat diet-induced FLHS chicken model to investigate the genome-wide active enhancers and transcriptome by H3K27ac target chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-Seq) profiles of normal and FLHS liver tissues. Concurrently, an integrative analysis combining ChIP-seq with RNA-Seq and a comparative analysis with chicken FLHS, rat non-alcoholic fatty liver disease (NAFLD) and human NAFLD at the transcriptome level revealed the enhancer and super enhancer target genes and conservative genes involved in metabolic processes. Results: In total, 56 and 199 peak-genes were identified in upregulated peak-genes positively regulated by H3K27ac (Cor (peak-gene correlation) ≥0.5 and log2(FoldChange) ≥1) (PP) and downregulated peak-genes positively regulated by H3K27ac (Cor (peak-gene correlation) ≥0.5 and log2(FoldChange)≤-1) (PN), respectively; then we screened key regulatory targets mainly distributing in lipid metabolism (PCK1, APOA4, APOA1, INHBE) and apoptosis (KIT, NTRK2) together with MAPK and PPAR signaling pathway in FLHS. Intriguingly, PCK1 was also significantly covered in up-regulated super-enhancers (SEs), which further implied the vital role of PCK1 during the development of FLHS. Conclusion: Together, our studies have identified potential therapeutic biomarkers of PCK1 and elucidated novel insights into the pathogenesis of FLHS, especially for the epigenetic perspective.

• Journal of The Korean Association For Science Education
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• v.40 no.4
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• pp.415-427
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• 2020

This study aims to understand science education conducted in North Korea by analyzing the PCK components shown in two science teacher's guidebooks: (1) Guidebook for 1^st grade elementary school and (2) Guidebook for 1^st grade middle school. These were published after 2013, when "the first 12-year Universal Compulsory Curriculum" was implemented in North Korea. The analysis shows that both elementary and middle school guidebooks had the highest percentage of content in "Knowledge of Subject Matter", followed by "Knowledge of Instructional Strategies in Science" and "Knowledge of Science Curriculum". On the other hand, "Knowledge of Assessment in Science" and "Knowledge of Students" were significantly low in content. Within the "Knowledge of Subject Matter", both elementary and middle schools had the highest proportion of content in "Concepts and Theories", along with "Experiments and Inquiries" that was also significantly higher than other PCK components. Science teacher's guidebooks in North Korea advocates constructivist teaching style by using "discussions" as the main activity when conveying scientific concepts and theories to students or conducting scientific inquiry classes. Furthermore, "Knowledge of Instructional Strategies in Science" was mainly focused on guiding the "Instruction sequence and method" from the "Topic-specific Strategies", while only a small part of the "Subject-specific Strategies" was being presented. Also, Science teacher's guide books in North Korea included only a few theoretical elements of science education in both the general outline and the particular sections of guidebooks. "Knowledge of Science Curriculum" was mainly composed of "Lesson Objectives" with some inclusion of "Vertical Articulation" and "Horizontal Articulation". "Knowledge of Assessment in Science" and "Knowledge of Students" accounted for a small portion compared to the science teacher's guidebooks in South Korea.

• Journal of The Korean Association For Science Education
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• v.39 no.5
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• pp.585-597
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• 2019

The purpose of this study is to analyze science subject items in the first screening stage of the elementary school teacher employment examination based on pedagogical content knowledge (PCK) and provide suggestions for improving the items. For this purpose, an analysis framework to analyze the items was developed and a total of 14 unit items between academic years of 2013 and 2019 were analyzed according to the analysis framework. The analysis of the results reveal that 'subject matter knowledge' of the five PCK components was most frequently included in the items. 'Instructional strategies and instruction for science education' was also frequently included although less than that of the previous component. However, 'assessment in science education', 'students', and 'curriculum for science education' were a little included. There were also assessment domains and contents which were not involved in the items. In the aspects of integration, the integrations between two components of two types were frequently found. No integrations were also frequently included although less than the previous category. The integrations among three or four components were also slightly found. Integrations among five components were not found. 'Subject matter knowledge' or 'instructional strategies and instruction for science education' with other components were more frequently found. However, the integrations of 'assessment in science education', 'students', and 'curriculum for science education' with the other components were less frequently found. Educational implications of these findings are discussed.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.520-532
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• 2015

The purposes of this study were to examine what kinds of educational activities were carried out during the practice teaching based on CoRe and to identify the role of CoRe and its influence on the development of expertise of student teachers. This study was performed as qualitative case study. The subjects of this study were one practice supervisor teacher and two student teachers. Data were collected through recording CoRe discussion process, student teachers' instructional scene, and semi-constructed interview, and analyzed by an inductive method. Student teachers noticed their own misconceptions, and clarified the concepts based on CoRe during the discussion with supervisor teacher. They also supplemented their lack of knowledge and made up new strategies through the process of sharing their ideas. During the discussion, the supervisor teacher conveyed his teaching experience based on his own orientations toward science teaching. In this course, CoRe plays roles as follows. Firstly, CoRe played a role as guiding supervisor teacher's coaching process. Secondly, CoRe helped for the supervisor teacher to recognize their own PCK. Thirdly, CoRe served as a tool of helping their communication. In turn CoRe proved to be a useful frame for teaching student teachers during practice teaching. Student teachers were provided with a useful framework for preparing lessons by developing CoRe for the topic they teach. Developing CoRe with supervisor teacher at the planning stage of lessons enhenced student-teachers' subject matter knowledge and their PCK including knowledge of science curricula and knowledge of student's understanding of science. Also student teachers understood the components of PCK and experienced the positive understanding toward students, teaching activities, and themselves as a science teacher.

• Journal of Korean Elementary Science Education
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• v.39 no.1
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• pp.100-116
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• 2020

The purpose of this study was to investigate the interaction of science PCK between two elementary school teachers by the teacher collaboration within the school. We chose the case that two teachers collaborated spontaneously in the 5th-grade science classes. Even though they had similar teaching experiences, one of them had the science PCK while the other did not. As a result of this study, two teachers began to collaborate to avoid comparisons of science classes between them. They shared the same teaching plan but practiced science teaching individually. During they taught science, they usually collaborated on the instructional sequences, student's activities, and the content of assessments. They had an in-depth collaboration when the teacher who lacked the science PCK asked help to teach problem-centered learning by science inquiry. During the collaboration, their science PCK components, especially the knowledge of instructional strategies for teaching science, shared and it affected the teacher's science practices who lacked the science PCK. However, they did not usually share the knowledge of teaching for their everyday science classes because two teachers had the perception of noninterference about their science classes. This case has the limitation that it is hard to generalize the results but teacher collaboration shows the possibility to develop the elementary school teachers' science professionalism by having peers in the school who can help them in science classes.

• Journal of the Korean Chemical Society
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• v.66 no.1
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• pp.15-30
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• 2022

The purpose of this study was to examine interactions among components of pedagogical content knowledge of middle school science teachers in a teacher learning community targeting science practice-based instruction. Data collection consisted of pre and post questionnaire and interview with each of five science teachers, audio-recording of teacher discussion in a teacher learning community, lesson plans, teacher written reflection, and video-recording of teaching practice. Qualitative data analysis revealed that there were two types of interactions, i.e., one-way interaction and two-ways interaction among components of pedagogical content knowledge of science teachers in a teacher learning community. There were also consecutive interactions as well as one-shot interaction. For two-ways interaction there were synchronous two-ways interaction in a teacher learning community meeting as well as consecutive two-ways interaction along with several meetings. This study provides implications that collaborative learning context in a teacher learning community should stimulate various types interactions among components of pedagogical content knowledge.