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개방형 탐구 및 모의 실험수업 경험이 예비물리교사의 인식에 미치는 영향 탐색
김효준,하상우 한국물리학회 2023 새물리 Vol.73 No.4
Experiments are fundamental aspect of scientific inquiry and its role in science education is crucial. However, many experimental classes in schools tend to focus on confirmation experiments that limit students’ ability to explore and inquire. This study aims to help preservice teachers in understanding the value of inquiry-based experimental classes by inviting them to participate in an open-ended inquiry. Fifteen preservice teachers who had minimal prior experience in conducting an open inquiry and teaching formal classes participated in this study. Through this study, they were able to identify the benefits of an open-ended experiment, noting that it was enjoyable and beneficial in fostering a deeper understanding of concepts. Moreover, they observed that open-ended inquiry is similar to what scientists do and thus must be experienced by students. They thought that laboratory instruction was crucial for effective teaching in schools. Nevertheless, they acknowledged that teaching experimentation requires substantial preparation and an in-depth understanding of the experiment. 실험은 과학의 중요한 활동 중 하나이므로 과학교육에서도 그 역할이 필수적이다. 하지만 학교 현장에서의 실험수업은 탐구 방법을 일방적으로 제시하는 확인 실험의 형태로 많이 진행되어 오히려 부정적인 효과가 나타난다. 본 연구는 예비교사들이 개방형 탐구 및 모의실험수업 진행 경험을 통해 탐구와 실험수업의 가치를 깨닫게 하려는 목적으로 수행되었다. 본 연구의 참여자는 사범대학 물리교육학과에서 중등물리실험지도 교과를 수강하는 15명의 예비교사였으며, 이들 대부분은 개방형 탐구 및 정식 수업 진행 경험이 거의 없었다. 연구를 위해 학기말 보고서, 수업 분석 기록지, 면담 자료가 활용되었으며, 모든 자료는 질적으로 분석되었다. 연구 결과 예비교사들은 개방형 탐구를 통해 개방형 실험의 가치를 깨닫고, 개방형 탐구가 즐거울 뿐만 아니라 개념 이해에도 도움이 된다고 표현했다. 특히 개방형 탐구는 과학자가 하는 일에 가까우므로, 학생들에게도 이를 경험하게 해줘야 한다고 생각했다. 또한 예비교사들은 모의 실험수업을 통해 실험수업이 재미있으며, 학교 현장에서의 수업에서도 필수적이라는 것을 깨달았다. 하지만 실험수업은 준비에 많은 노력이 필요하며, 실험 내용에 대한 교사의 철저한 이해가 필요하다고 생각했다.
김효준,Lee Jin-Haeng,Lee Ki Baek,Shin Ji-Woong,Kwon Mee-ae,Lee Soojin,Jeong Eui Man,Cho Sung-Yup,Kim In-Gyu 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
Glutathione S-transferase (GST) from Schistosoma japonicum has been widely used as a tag for affinity purification and pulldown of fusion proteins to detect protein–protein interactions. However, the reliability of this technique is undermined by the formation of GST-fused protein aggregates after incubation with cell lysates. It remains unknown why this aggregation occurs. Here, we demonstrate that the GST tag is a substrate of transglutaminase 2 (TG2), which is a calcium-dependent enzyme that polyaminates or crosslinks substrate proteins. Mutation analysis identified four glutamine residues in the GST tag as polyamination sites. TG2-mediated modification of the GST tag caused aggregate formation but did not affect its glutathione binding affinity. When incubated with cell lysates, GST tag aggregation was dependent on cellular TG2 expression levels. A GST mutant in which four glutamine residues were replaced with asparagine (GST 4QN ) exhibited a glutathione binding affinity similar to that of wild-type GST and could be purified by glutathione affinity chromatography. Moreover, the use of GST 4QN as a tag reduced fused p53 aggregation and enhanced the induction of p21 transcription and apoptosis in cells treated with 5-fluorouracil (5-FU). These results indicated that TG2 interferes with the protein–protein interactions of GST-fused proteins by crosslinking the GST tag; therefore, a GST 4QN tag could improve the reproducibility and reliability of GST pulldown experiments.
Transglutaminase 2 mediates transcriptional regulation through BAF250a polyamination
김효준,Jin-Haeng Lee,Sung-Yup Cho,Ju-Hong Jeon,김인규 한국유전학회 2021 Genes & Genomics Vol.43 No.4
Background Transglutaminase 2 (TG2) mediates protein modifcations by crosslinking or by incorporating polyamine in response to oxidative or DNA-damaging stress, thereby regulating apoptosis, extracellular matrix formation, and infammation. The regulation of transcriptional activity by TG2-mediated histone serotonylation or by Sp1 crosslinking may also contribute to cellular stress responses. Objective In this study, we attempted to identify TG2-interacting proteins to better understand the role of TG2 in transcriptional regulation. Methods Using a yeast two-hybrid assay to screen a HeLa cell cDNA library, we found that TG2 bound BAF250a, a core subunit of the cBAF chromatin remodeling complex, through an interaction between the TG2 barrel 1 and BAF250a C-terminal domains. Results TG2 was pulled down with a GST-BAF250a C-term fusion protein. Moreover, TG2 and BAF250a were co-fractionated using P11 chromatography, and co-immunoprecipitated. A transamidation reaction showed that TG2 mediated incorporation of polyamine into BAF250a. In glucocorticoid response-element reporter-expressing cells, TG2 overexpression increased the luciferase reporter activity in a transamidation-dependent manner. In addition, a comparison of genome-wide gene expression between wild-type and TG2-defcient primary hepatocytes in response to dexamethasone treatment showed that TG2 further enhanced or suppressed the expression of dexamethasone-regulated genes that were identifed by a gene ontology enrichment analysis. Conclusion Thus, our results indicate that TG2 regulates transcriptional activity through BAF250a polyamination.
저온 분무 열분해법으로 제조된 Sr-ferrite의 자기특성
김효준,조태식,남효덕,양충진 한국전기전자재료학회 1998 전기전자재료학회논문지 Vol.11 No.10
Preparation of the hexagonal Sr-ferrite powsers with high performance by co-spraying precusor of the FeCl$_2$+SrCO$_3$ at a low temperature was proved as a cost =-effective method. The co-spray roasting was carried out in the temperature range of 300~$700^{\circ}C$ after SrCO$_3$ powders were mixed into 12FeCi$_2$.4$H_2O$ liquor. By this low temperature roasting method fine particles of multi-phased FeO$_2$+SrCO$_3$ were formulated. Powders calcined at 105$0^{\circ}C$ for 1 hour show the best magnetic property of M\ulcorner=69.96 emu/g, M\ulcorner=36.98 emu/g, and \ulcornerH\ulcorner=4.31 Oe. This calcining temperature is lower than that of the conventional dry method by 10$0^{\circ}C$.