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헴철이 풍부한 영양원이 혐기성 세균의 생장과 생존에 미치는 영향: 락토바실러스 가세리 모델연구
이승기 ( Seungki Lee ),김필 ( Pil Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 한국미생물·생명공학회지 Vol.49 No.1
Lactic acid bacteria (LAB), belonging to the Firmicutes phylum, lack heme biosynthesis and, thus, are characterized as fermentative and catalase-negative organisms. To verify the hypothesis that heme-rich-nutrients might compensate the heme-biosynthesis incapability of non-respiratory LAB in animal gut, a heme-rich-nutrient was fed to a dog and its fecal microbiome was analyzed. Firmicutes abundance in the feces from the heme-rich-nutrient-fed dog was 99%, compared to 92% in the control dog. To clarify the reason of increased Firmicutes abundance in the feces from the heme-rich-nutrient-fed dog, Lacobacillus gasseri were used as model anerobic LAB to study a purified heme (hemin). The anaerobic growth of L. gasseri in the medium with 25 μM hemin supplementation was faster than that in the medium without hemin, while the growth in the 50 μM hemin-supplemented medium did not vary. Cellular activities of the cytochrome bd complex were 1.55 ± 0.19, 2.11 ± 0.14, and 2.20 ± 0.08 U/gcell in the cells from 0, 25, and 50 μM hemin-supplemented medium, while intracellular ATP concentrations were 7.90 ± 1.12, 11.95 ± 0.68, and 12.56 ± 0.58 μmol<sub>ATP</sub>/g<sub>cell</sub>, respectively. The ROS-scavenging activities of the L. gasseri cytosol from 25 μM and 50 μM hemin-supplemented medium were 68% and 82% greater than those of the cytosol from no hemin supplemented-medium, respectively. These findings indicate that external hemin could compensate the heme-biosynthesis incapability of L. gasseri by increasing the cytosolic ROS-scavenging and extra ATP generation, possibly through increasing the electron transfer. Increase in the number of anaerobic bacteria in heme-rich-nutrient-fed animal gut is discussed based on the results.
디바이스넷 기반의 유무선 혼합형 게이트웨이의 성능 분석
정지원(Ji-won Jung),이승기(SeungKi Lee),김동성(Dong-Sung Kim) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.4
This paper is concerned with a performance analysis using a wired/wireless gateway based on DeviceNet. For the performance analysis, the data transmission time between DeviceNet and the wireless devices is investigated and analyzed. The experimental results show the performance in terms of the polling/COS service time and end-to-end delay.