Novel strategy for high-throughput screening to improve photosynthetic CO₂ conversion using microaglae

최홍일,김영환,심상준 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

In the study, we conceived a novel microfluidic-based strategy utilizing phototactic response of Chlamydomonas reinhardtii for high-throughput screening of mutants with improved photosynthetic efficiency. We detected responses of mutants with different photosynthetic parameters by monitoring their phototactic movements at the level of individual cells in microfluidic devices. We statistically analyzed phototactic movements and compared the physical parameters regarding phototactic movements with conventional photosynthetic parameters such as chlorophyll a/b ratio, photochemical quenching, non-photochemical quenching. Mutants with higher qP and lower NPQ values, which are desirable traits for efficient photosynthesis, showed more light-sensitive responses. This result implies that phototactic response in microfluidic device can be a more useful indicator for prediction and selection of superior strains with improved photosynthetic efficiency.

Development of Reproducible EST-derived SSR Markers and Assessment of Genetic Diversity in Panax ginseng Cultivars and Related Species

최홍일,김남훈,김준하,최범순,안인옥,이준수,양태진 고려인삼학회 2011 Journal of Ginseng Research Vol.35 No.4

Little is known about the genetics or genomics of Panax ginseng. In this study, we developed 70 expressed sequence tagderived polymorphic simple sequence repeat markers by trials of 140 primer pairs. All of the 70 markers showed reproducible polymorphism among four Panax species and 19 of them were polymorphic in six P. ginseng cultivars. These markers segregated 1:2:1 manner of Mendelian inheritance in an F2 population of a cross between two P. ginseng cultivars, ‘Yunpoong’ and ‘Chunpoong’,indicating that these are reproducible and inheritable mappable markers. A phylogenetic analysis using the genotype data showed three distinctive groups: a P. ginseng-P. japonicus clade, P. notoginseng and P. quinquefolius, with similarity coefficients of 0.70. P. japonicus was intermingled with P. ginseng cultivars, indicating that both species have similar genetic backgrounds. P. ginseng cultivars were subdivided into three minor groups: an independent cultivar ‘Chunpoong’, a subgroup with three accessions including two cultivars, ‘Gumpoong’ and ‘Yunpoong’ and one landrace ‘Hwangsook’ and another subgroup with two accessions including one cultivar, ‘Gopoong’ and one landrace ‘Jakyung’. Each primer pair produced 1 to 4 bands, indicating that the ginseng genome has a highly replicated paleopolyploid genome structure.

Energy and Environmental Benefits of Microalgal Biomass as a Direct Combustion Fuel

최홍일,심상준 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Microalgae have garnered considerable attention for their ability to produce various products utilizing CO₂. Especially, microalgae are considered to be the most promising candidate for biodiesel production platform. However, the production of biodiesel from microalgae requires cumbersome downstream stages, such as lipid extraction, trans-esterification and separation process, which negate CO₂ reducing effects and energetic benefit of the biomass energy source. In this point of view, the utilization of microalgal biomass as a direct combustion fuel is worth reconsidering. This is because it only needs simple dehydration system for the practical use. In this study, we studied the various benefits of microalgal biomass as a solid fuel. As a result, we found that microalgal biomass solid fuel chain is a practical CO₂-negative fuel system.

Quantitative Chemotaxis Analysis of a Model Microalga, Chlamydomonas reinhardtii, towards Bicarbonate with Agarose-Gel Microfluidic Device

최홍일,심상준 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Microalgae have attracted considerable attention for their ability to produce various products utilizing CO₂. Despite the importance, various biological phenomena are still unknown. Here, we examined the chemotaxis of C. reinhardtii towards HCO₃^- using a hydrogel (agarose)-based microfluidic device. The availability of the device was tested by previously studied chemicals: NH₄Cl and CoCl₂ are chemoattractants, while NaCl is neutral. We observed the chemotaxis of C. reinhardtii towards HCO₃^- and found the concentration for the strongest response. In diurnal chemotaxis assay, the chemotaxis peaked in the middle of the night while the response was quite low during the daytime. Furthermore, we verified several factors influencing on carbon concentrating mechanism (CCM) caused significant change in the chemotactic behavior. This study would provide a fundamental of HCO₃^--induced chemotaxis and may promote the understanding of inorganic carbon utilization.

Direct combustion opens up new possibilities for microalgae-based energy systems

최홍일,심상준 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1

학교 밖 청소년이 경험하는 사회적 낙인감이 생활 만족도에 미치는 영향: 우울감과 자아존중감의 이중매개효과를 중심으로

최홍일,이래혁 한국학교사회복지학회 2020 학교사회복지 Vol.0 No.52

The efforts in social welfare to support the healthy development of out-of-school adolescents have been requested. This study aimed to examine the influence of social stigma on life satisfaction among out-of-school adolescents and to investigate the structural relations of depression and self-esteem in the influence. For the purpose, this study used data from the 2nd wave of the Panel Survey of School Dropouts performed by the National Youth Policy Institute and conducted data analyses by utilizing a structural equation model. The results are as follows. First, out-of-school adolescents’ social stigma influenced significantly negatively life satisfaction. Second, out-of-school adolescents’ depression and self-esteem mediated the influence of social stigma on life satisfaction. Levels of social stigma increased levels of depression and, in turn, decreased levels of life satisfaction. Also, levels of social stigma decreased levels of self-esteem and, in turn, decreased levels of life satisfaction. Third, out-of-school adolescents’ depression and self-esteem double-mediated the influence of social stigma on life satisfaction. Levels of social stigma increased levels of depression and then decreased levels of self-esteem, and finally decreased levels of life satisfaction. Based on the findings of this study, diverse intervention strategies to improve the life satisfaction of out-of-school adolescents were discussed. 학교 밖 청소년을 지원하여 건강한 사회구성원으로 성장시키기 위한 사회복지 분야의 노력이 요구되고 있다. 본 연구는 학교 밖 청소년의 생활 만족도에 사회적 낙인감이 미치는 영향력과 우울감 및 자아존중감의 구조적 관계를 확인하고자 하는 목적으로 수행되었다. 이를 위해 한국청소년정책연구원에서 구축한 학업중단 청소년 패널 자료와 구조방정식 모형을 사용하여 분석을 수행하였다. 분석의 결과는 다음과 같다. 첫째, 학교 밖 청소년이 인식하는 사회적 낙인감은 생활 만족도에 부적으로 유의미한 영향을 미쳤다. 둘째, 학교 밖 청소년의 우울감 및 자아존중감은 사회적 낙인감과 생활 만족도의 관계를 매개했다. 즉, 사회적 낙인감은 우울감을 높이거나 자아존중감을 낮추어 생활 만족도를 감소시키고 있었다. 셋째, 학교 밖 청소년의 우울감과 자아존중감은 사회적 낙인감과 생활 만족도 사이의 관계를 이중매개하고 있었다. 즉, 사회적 낙인감은 우울감을 높이고 이어서 자아존중감을 낮추어 최종적으로 생활 만족도를 감소시키고 있었다. 본 연구의 결과를 토대로 학교 밖 청소년의 생활 만족도를 향상시킬 수 있는 다양한 실천적 개입 방안을 논의하였다.

스마트폰 과의존이 청소년의 주의력 결핍에 미치는 영향 -수면의 질과 우울의 연속다중매개효과를 중심으로-

최홍일,정현주 한국아동복지학회 2023 한국아동복지학 Vol.72 No.1

청소년들의 스마트폰 과의존과 우울, 수면의 질, 주의력결핍과 같은 다양한 심리정서적 어려움 간의 관계에 대해 많은 연구가 있었지만, 스마트폰과의존과 주의력결핍과의 관계, 우울이나 수면의 질이 이 관계를 매개하는지의 여부 등에 대한 것은 알려진 것이 적다. 이에 본 연구에서는 청소년의스마트폰 과의존과 주의력 결핍의 관계에 영향을 미치는 다양한 변수들 중우울과 수면의 질의 다중매개효과를 살펴봄으로써, 기저에 있는 메커니즘을탐색하고자 하였다. 이를 위해 한국아동청소년패널 2018 초4패널의 3차년도총 2,364명의 데이터(학교급 초등학교 6학년)를 가지고 다중매개효과 분석을 하였다. 연구결과, 스마트폰 과의존은 청소년의 주의력 결핍을 야기하는것으로 나타났다. 스마트폰 과의존은 수면의 질을 저하하고, 저하된 수면의질은 주의력 결핍을 불러일으킨다. 한편 스마트폰 과의존은 우울을 증가시키는 경향이 있으며, 우울의 매개효과를 거쳐 주의력 결핍을 증가시킨다. 이들 관계를 종합하면, 스마트폰 과의존은 수면의 질 저하를 거쳐 우울을증가시키고, 그 결과 주의력 결핍을 증가시키고 있었다. 이렇듯 본 연구의결과는 청소년의 스마트폰 과의존과 우울, 수면의 질, 주의력 결핍과 같은심리정서적 어려움간의 복합적인 관계를 증명하고 있다. 이를 바탕으로 청소년들의 스마트폰 과의존에 관한 근본적이고 종합적인 예방과 치료가 이들의 주의력 결핍, 수면의 질, 우울 문제 해결을 위한 방안 중 하나로 고려되어야 하는 필요성이 확인되었다.

Statistical analysis for screening microalgal strains based on their chemotactic responses in microfluidic devices

최홍일,장원석,심상준 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

According to the previous studies, many aquatic photosynthetic organisms, such as microalgae utilize carbon dioxide (CO2) and bicarbonate (HCO3-) as carbon sources through CO2 concentrating mechanism. In this point of view, we tried to observe the existence of chemotaxis toward HCO3 - and verify the relationship between the extent of the chemotactic response and carbon dioxide fixation efficiency of the wild-type and mutants of a motile microalga, Chlamydomonas reinhardtii CC125 through various micro systems. As a result, we confirmed the microalga shows chemotactic response toward HCO3-. In addition, the correlations between the extent of chemotaxis and carbon dioxide fixation efficiency showed meaningful relationships. This result implies that this strategy can be used for high-throughput screening to find the microalgal strains with high CO2 fixation efficiency.

Microfluidic-based screening strategy using chemotactic response of microalgae for efficient CO₂ fixation

최홍일,성영준,김영환,심상준 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

Chemotaxis is movement of an organism in response to a chemical signal. In this study, we observed the chemotactic behavior of a motile microalga, Chlamydomonas reinhardtii, in various systems. According to the previous studies, Chlamydomonas reinhardtii utilizes carbon dioxide (CO₂) and bicarbonate ion (HCO₃ ^-) as carbon sources at the same time. It is expected that the chemotactic response to HCO₃ ^- is related to the CO₂ fixation efficiency. Firstly, we devised a flow-free microfluidic system and observed the chemotactic response to the different concentrations of HCO₃ ^-. As a result, we found the most preferred concentration is 30mM. Based on this result, we designed a flowing system for strain screening. Well-growing mutants showed a tendency to prefer higher concentration. This result implies that the strategy can be used for high-throughput screening to find the superior microalgal strains with high efficiency of CO₂ fixation.

재만한인 공산주의자들의 항일무장투쟁에 관한 국내외 언론의 인식

최홍일 한국민족운동사학회 2007 한국민족운동사연구 Vol.0 No.51