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Fructan Biosynthesis by Yeast Cell Factories
Ko Hyunjun,Sung Bong Hyun,Kim Mi-Jin,Jung-Hoon Sohn,Bae Jung-Hoon 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.11
Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.
Ko, Hyunjun,Bae, Jung-Hoon,Kim, Mi-Jin,Sung, Bong Hyun,Sohn, Jung-Hoon ELSEVIER 2019 INDUSTRIAL CROPS AND PRODUCTS Vol. No.
<P><B>Abstract</B></P> <P>Difructose anhydride III (DFA III), a functional sweetener, is enzymatically produced from inulin by inulin fructotransferase (IFTase; EC 4.2.2.18). Here, a recombinant yeast strain hyper-secreting IFTase from <I>Arthrobacter aurescens</I> was developed by employing the translational fusion partner technique, and the recombinant yeast produced 77.5 g (64.6% yield) of DFA III from 200 g of crude extract of Jerusalem artichoke tuber powder containing 120 g of inulin during direct fermentation. The sugar purity of DFA III was increased up to 95% by additional incubation with <I>Kluyveromyces marxianus</I>. This study is the first report of the secretory production of recombinant IFTase in <I>Saccharomyces cerevisiae</I>, and the direct conversion of DFA III from crude extract of Jerusalem artichoke tuber powder by microbial fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A recombinant <I>Saccharomyces cerevisiae</I> hyper-secreting inulin fructotransferase (161.6 U/mL) was developed. </LI> <LI> The strain produced 77.5 g of DFA III from 200 g of Jerusalem artichoke tuber powder. </LI> <LI> By additional culture of <I>Kluyveromyces marxianus</I>, the DFA III content based on carbohydrates was increased up to 95%. </LI> <LI> This is the first direct production of DFA III from crude JAP by microbial fermentation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
실시간 임베디드 시스템에서의 YOLO 네트워크를 위한 필터 가지치기 기법 연구
고현준(Hyunjun Ko),김재명(Jaemyung Kim),박현재(Hyunjae Park),강진구(Jin-Ku Kang),김용우(Yongwoo Kim) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6
Recently, object detection networks using Convolutional neural networks (CNNs) have shown outstanding performance in the field of computer vision. However, these networks consist of a large number of parameters and floating-point operations(FLOPs). Therefore, it is difficult to implement the CNN networks to real-time embedded systems such as cars or drones. In this paper, we implement target capacity filter pruning (TCFP) on YOLOv7 and YOLOv8 to reduce the number of parameters and FLOPs. In addition, we analysis networks performance on NVIDIA Jetson Xavier NX. As a result, inference time of YOLOv7 and YOLOv8 is improved about 11.4% and 19.2% on each networks and mAP(0.5:0.95) decreased only about 3.8% and 7% when pruning rate is 50% on COCO dataset.
고현준(Hyunjun Ko),김남열(Namyeul Kim),현정근(Jungguen Hyun),정우철(Woochul Jeong),강모원(Mowon Kang),김종형(Jonghyeong Kim) 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.3-1
In general, manual wheelchairs have played important roles in moving patients from one place to another. However, patients have experienced discomfort getting on and off because of the need for physical assistance. This can be more serious if a patient has handicaps involving the arms or legs. In addition, it could be unpleasant for both the patient and assistant because of the need for extensive physical contact with each other. At times, a weak nurse feels that there is a risk when transferring a heavy patient from a bed to a wheelchair. In this paper, a new non-powered wheelchair is designed to assist in transferring a patient to their bed. This design considers the convenience of both the patient and assistant when the patient is transferred from a wheelchair to a bed and vice versa. The operation minimizes the physical contact between the assistant and the patient. The new wheelchair is also lightweight and portable compared with the normal popular wheelchair.
효모에 발현된 북방수염하늘소(Monochamus saltuarius) Cellulase gene MsGHF45의 특성에 관한 연구
고현진 ( Hyeon Jin Ko ),고현준 ( Hyunjun Ko ),홍순관 ( Soon Kwan Hong ),박용철 ( Yong Chul Park ) 한국임학회 2016 한국산림과학회지 Vol.105 No.2
화석연료의 고갈 문제로 인하여 다양한 대체에너지가 개발 중이며 본 연구에서는 바이오에탄올 연구의 초석으로 사용하기 위해 곤충의 효소를 연구하였다. 북방수염하늘소(Monochamus saltuarius Gebler)가 지닌 cellulase (MsGHF45) 유전자를 Kluyveromyces lactis에 형질전환 시켰다. 형질전환 된 효모는 활성이 있는 cellulase 효소를 성공적으로 생산하였다. 재조합 MsGHF45의 분자량은 SDS-PAGE와 western blot을 통하여 확인하였다. 효소의 활성은 기질로써 carboxymethyl cellulose를 첨가한 native-PAGE를 통해서 검증하였다. 효소 활성의 최적조건을 알아본 결과, pH는 5에서, 온도는 40℃에서 나타났다. 바륨이온(Ba2+)과 철이온(Fe2+)은 효소활성을 저해하지 않았으나, 칼슘이온(Ca2+), 코발트이온(Co2+), 구리이온(Cu2+), 수은이온(Hg2+), 마그네슘이온(Mg2+), 망간이온(Mn2+) 그리고 아연이온(Zn2+)은 활성을 저해하였다. 특히, 수은이온은 효소활성을 66.5% 감소시켰다. 본 연구는 다양한 효소를 이용한 biofuel 연구에 참고자료로 사용될 것이다. In this study, the cellulase of Monochamus saltuarius (MsGHF45) gene was introduced in Kluyveromyces lactis, successfully. The molecular weight of recombinant enzyme was determined by SDS-PAGE and western blotting. The enzymatic activity was confirmed by native-PAGE containing carboxymethyl cellulose as a substrate. The optimul pH and temperature of recombinant MsGHF45 was pH5 and 40℃. The barium (Ba2+) and ferrous (Fe2+) enhanced enzyme activity, and the mercuty (Hg2+) inhibited its activity.
고웅현(Ung Hyun Ko),홍정우(Jungwoo Hong),신현준(Hyunjun Shin),김철웅(Cheol Woong Kim),신현정(Jennifer H. Shin) Korean Society for Precision Engineering 2015 한국정밀공학회지 Vol.32 No.8
For proper wound healing, dermal contraction and remodeling are critical; during the natural healing process, differentiated fibroblasts called “myofibroblasts” typically undertake these functions. For severe wounds, however, a critical mass of dermal matrix and fibroblasts are lost, making self-regeneration impossible. To overcome this impairment, synthetic wound patches with embedded functional cells can be used to promote healing. In this study, we developed a polydioxanone (PDO)-based cell-embedded sheet on which dermal fibroblasts were cultured and induced for differentiation into myofibroblasts, whereby the following combinatorial physicochemical stimuli were also applied: aligned topology, electric field (EF), and growth factor. The results show that both the aligned topology and EF synergistically enhanced the expression of alpha smoothmuscle actin (α-SMA), a key myofibroblast marker. Our proof-of-concept (POC) experiments demonstrated the potential applicability of a myofibroblast-embedded PDO sheet as a wound patch.
Yunhee Chang,Chang-Yong Ko,Bo Ra Jeong,Jung Sun Kang,Hyuk-Jae Choi,Gyoosuk Kim,Hyunjun Shin,Sehoon Park 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.3
When applying prosthetic gait training to patients with lower limb amputation, monitoring the gait change process is crucial for establishing and modifying rehabilitation training plans. In addition, since human gait involves complex movement of several joints, it is necessary to analyze the organic movement of adjacent joints rather than a single joint in the lower extremities for understanding the process of gait change. Therefore, this study aimed to analyze changes in spatiotemporal parameters and lower limb coordination during prosthetic gait training in unilateral transfemoral amputees (TFAs). This retrospective case–control study included 10 unilateral TFAs and 10 healthy individuals as controls. TFAs received prosthetic gait training for 12 weeks and gait changes were analyzed every 2 weeks using a 3D motion analysis system. The measured variables were spatiotemporal parameters and the continuous relative phase between hip and knee joints. The highest improvement in walking speed was seen at week 4 of training, and the continuous relative phase was most symmetric at week 8. The lower limb coordination pattern was more in-phase in the TFAs than in the controls, and the coordination variability was also lower for the TFAs than for the controls. In addition, the rate of change in lower limb coordination of TFAs was lower than that of spatiotemporal parameters and was significantly different from that of the controls even after training. Considering that the decrease in lower limb coordination is related to gait efficiency, balance, and risk of fall, there is a need to develop therapeutic strategies that can further improve the coordination of TFAs.