Antimicrobial compounds from lactic acid bacteria and their application in the food industry

Hyungjae Lee 한국산업식품공학회 2013 식품과 기계 Vol.10 No.1

식품계열 자격증 소지자의 현장 활동현황과 제언

이형재(Hyungjae Lee) 한국식품과학회 2007 식품과학과 산업 Vol.40 No.3

호알칼리성 Bacillus sp. DK1122 균주가 생산하는 알칼리성 단백질 분해효소의 정제 및 특성

이형재 ( Hyungjae Lee ),유지승 ( Ji Seung Yoo ),배동훈 ( Dong Hoon Bai ) 한국미생물생명공학회(구 한국산업미생물학회) 2016 한국미생물·생명공학회지 Vol.44 No.3

호알칼리성 protease를 분비하는 토양에서 분리된 Bacillus sp. DK1122 균주로부터 효소의 생산조건을 검토 후, 효소를 정제하고 특성을 알아보았다. 본 균주의 효소생산 최적 배지 조성은 0.5% (w/v) glucose, 0.8% (w/v) yeast extract, 0.5% (w/v) polypeptone, 0.1% (w/v) K2HPO4, 0.02% (w/v) MgSO4· 7H2O, 1% (w/v) Na2CO3, 3% (w/v) NaCl, pH 9.0이었으며, 종배양액 0.5% 접종시 40℃에서 24시간 배양했을 때 효소 생산량이 가장 높았다. Bacillus sp. DK1122가 생산하는 alkaline protease를 70% 포화 ammonium sulfate로 침전시키고, CM-Sepharose column chromatography에 의해 23.9%의 수율에 2.8배의 정제도를 지니는 효소를 얻을 수 있었다. SDS-PAGE를 통해 정제된 protease는 27 kDa의 크기의 단일 subunit으로 확인되었고, 정제된 효소의 최적 pH는 9.0, 최적온도는 60℃였으며, 50℃에서 1시간까지 열에 안정하였고, 60℃에서 10 mM CaCl2 첨가 후 3시간까지 90%의 활성을 유지하여 Ca2+에 의해 열안정성이 증가하였다. 본 연구를 통해 정제된 호알칼리성 protease는 식품, 세제 및 관련산업에서의 응용성이 매우 높을 것으로 기대된다. An alkaline protease was purified and characterized from an alkalophilic microorganism, Bacillus sp. DK1122, isolated from soil in central Korea. The optimum temperature and pH for the growth of the producer strain were 40℃ and pH 9.0, respectively. The protease was produced aerobically at 40℃ after 24 h incubation in modified Horikoshi I medium (pH 9.0) containing 0.5% (w/v) glucose, 0.8% (w/v) yeast extract, 0.5% (w/v) polypeptone, 0.1% (w/v) K2HPO4, 0.02% (w/v) MgSO4·7H2O, 1% (w/v) Na2CO3, and 3% (w/v) NaCl. The alkaline protease was purified by 70% ammonium sulfate precipitation of the culture supernatant of Bacillus sp. DK1122, followed by CM-Sepharose chromatography. The molecular weight of the enzyme was estimated to be 27 kDa on the basis of SDS-PAGE. The optimum temperature and pH for the protease activity were 60℃ and pH 9.0, respectively. Addition of CaCl2 increased the thermal stability of the purified protease, where 90% of protease activity was retained at 60℃ for up to 3 h. Consequently, it is expected that the alkaline protease from this study, exhibiting stability at pH 7-9 and 60℃, may be promising for application in the food and detergent industries.

Dynamic Adjustment of Noncooperative Games Where Informations are Given at Discrete Time Intervals

Oh, Hyungjae 한국경영과학회 1990 韓國經營科學會誌 Vol.15 No.2

This paper concerns the analyses of dynamic adjustments in noncooperative games where the market informations are given at discrete time intervals. During the game period, the inventories initially stored by players are to be released one day based to the completely competitive market so as to maximize each palyer's revenue, where players' parameters are unknown one another. Game results have shown that the continuous dynamic adjustment does not necessarily assure the better revenue, and if a player thinks that his parameter is underestimated by his opponent, then his is better overestimate his opponent's parameter.

북 핵 위협 대응을 위한 지휘통제체계 발전방안 : 인공지능 기술을 적용한 지능화 항공우주작전본부 구축

이형재(Hyungjae Lee) 육군사관학교 화랑대연구소 2021 한국군사학논집 Vol.77 No.3

If we have a command and control system that guarantees a more swift and accurate decision-making than the enemy, we can exert greater power with only our existing forces, and ultimately increase our deterrence against the enemy. Therefore, this study asserts that in order to maximize the efficacy of Korea"s nuclear and WMD response system, it is necessary to enhance the command and control capabilities along with force reinforcement. The quality and speed of decision-making can be improved by applying AI technology to the Air & Space Operations Center, which is the command and control system to be used by the operations center of the nuclear and WMD response system. By applying AI technology to AOC, it will be possible to simultaneously respond to North Korea"s conventional threats as well as nuclear and missile threats.

Electroactive Polypyrrole Nanowire Arrays: Synergistic Effect of Cancer Treatment by On-Demand Drug Release and Photothermal Therapy

Lee, HyungJae,Hong, Wooyoung,Jeon, Seunghyun,Choi, Yongdoo,Cho, Youngnam American Chemical Society 2015 Langmuir Vol.31 No.14

<P>An electroresponsive drug release system based on polypyrrole (Ppy) nanowires was developed to induce the local delivery of anticancer drug, doxorubicin (DOX), according to the applied electric field. DOX-conjugated Ppy nanowire (NW) (DOX/Ppy NW) array was initially prepared by electrochemical deposition of a mixture of pyrrole monomers and biotin as dopants in the anodic alumina oxide membrane as a sacrificial template. Morphological observation by scanning electron microscopy revealed free-standing and 3D nanotopographical features with large surface area and high density. In addition, we investigated the antitumor efficacy of DOX released from DOX/Ppy NW array in response to the external electric field using two kinds of cancer cell lines, human oral squamous carcinoma cells (KB cells) and human breast cancer cells (MCF7 cells). Meanwhile, strong photothermal effect as a result of a near-infrared absorbing ability of Ppy synergistically maximizes the chemotherapeutic efficacy. Our results suggested that the proposed multifunctional Ppy platform possessing several beneficial features is very promising for many therapeutic applications including cancer.</P>

가상현실(Vritual Reality)을 활용한 소규모 영상 프로덕션의 가상제작 공정 최적화 설계 연구

김형재(Hyungjae Kim) 한국콘텐츠학회 2023 한국콘텐츠학회논문지 Vol.23 No.12

현대 영상 기술의 발전은 영상 제작의 접근성 향상과 디지털 미디어의 확산으로 관객의 다양한 수요 증가를 이끌었다. 이러한 흐름에 따라 영상 산업은 전략적 경쟁력과 혁신적 제작 방식에 주목하였다. 특히, 소규모 영상 제작 회사들은 가상 제작(Virtual Production) 같은 첨단 기술에 눈길을 돌렸다. 가상 제작은 실시간 컴퓨터 그래픽스, VR, AR 및 모션 캡처 등의 디지털 기술을 융합, 전통적 제작 방식의 현대화에 기여한다. 이 기술의 장점은 제작 비용 절감 및 현실적 장면의 신속한 구현으로, 영상 프로덕션 분야에서의 활용 가능성을 부각시켰다. 본 연구는 소규모 영상 프로덕션을 위한 가상 제작 활용법을 논의하며, 제한된 자원하에서도 가상 제작 기술을 통한 효율적인 영상 제작 과정 설계를 제안한다. 연구의 중점은 현재 출시된 가상 제작 하드웨어 중 비용효율이 높은 하드웨어를 선택하고 소프트웨어와의 호환성을 연구하여 다양한 제작 환경에 최적화하는 작업을 검증하는 것이다. 제안된 방식으로 제작된 작품을 통해 제작 비용의 절감, 제작 시간의 단축, 그리고 팀 간의 효율적인 커뮤니케이션의 장점을 확인하였다. 더불어 대형 영상 제작 회사의 가상 제작 결과물과 유사한 고도의 시각적 표현력이 달성됨을 확인하였다. The evolution of contemporary imaging technologies has enhanced accessibility to video production, and in tandem with the expansion of digital media, has catalyzed a rise in the audiences diverse demands. This progression has led the film industry to focus on strategic competitiveness and the adoption of innovative production methodologies. Particularly, small-scale video production companies have turned their attention to cutting-edge technologies such as Virtual Production (VP). VP integrates digital technologies like real-time computer graphics, Virtual Reality (VR), Augmented Reality (AR), and motion capture, contributing significantly to the modernization of traditional production methods. The key advantages of this technology include the reduction of production costs and the quick realization of realistic scenes, thus highlighting its potential for application in the domain of video production. This study discusses the application of VP in small-scale video productions, suggesting an efficient production process design utilizing VP technology, even within the confines of limited resources. The primary focus is on selecting cost-effective hardware from the currently available VP equipment, examining its compatibility with various software to optimize it for different production settings. The methodology proposed was validated through productions that not only demonstrated reductions in production costs and time but also facilitated efficient communication within teams. Furthermore, it was observed that this approach enabled the achievement of a high degree of visual expressiveness, comparable to that of large-scale production companies VP outputs.

Magnetic nanowires for rapid and ultrasensitive isolation of DNA from cervical specimens for the detection of multiple human papillomaviruses genotypes

Lee, HyungJae,Hwang, Na Rae,Hwang, Sang-Hyun,Cho, Youngnam Elsevier 2016 Biosensors & bioelectronics Vol.86 No.-

<P><B>Abstract</B></P> <P>Detecting human papillomavirus (HPV) is central in diagnosing and monitoring HPV-related disease. However, limited sensitivity and the wide variability of the HPV genome pose challenges in the identification of HPV genes, particularly high-risk types. This study reports the development of polyethyleneimine-conjugated magnetic nanowires (PEI-MNWs) and their use in the isolation, identification, and analysis of multiple genotypes of HPV DNA from cervical cancer specimens. The nanowires are electrochemically doped with a high density of magnetic nanoparticles and biotin moieties during potentiostatic deposition, thereby allowing conjugating cationic branched polymers to direct the attachment of negatively charged DNA molecules with strong magnetic response. For proof of concept, the rapid and ultrasensitive isolation of HPV DNA is performed at concentrations as low as 10pg/mL with an efficiency of >95%. For clinical optimization, the analytical and clinical sensitivity of PEI-MNWs is compared with that of the Roche Cobas 4800 HPV Test and demonstrates excellent correlation for multiple HPV DNA genotypes with superior threshold cycle values. The high sensitivity, specificity, and good reproducibility of PEI-MNWs are particularly well suited for the recovery of DNA and provide significant and clinically meaningful evidence for the early detection and treatment of HPV-associated cancers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The magnetic nanowires were electrochemically developed via potentiostatic deposition. </LI> <LI> Nanowires enhance the attachment of polymer chains that ultimately improve DNA recovery. </LI> <LI> Nanowires demonstrated the isolation and analysis of multiple genotypes of HPV DNA. </LI> <LI> HPV DNA detection and genotyping was confirmed for analytical and clinical validation. </LI> </UL> </P>

알칼리성 단백질 분해효소를 생산하는 토양 분리 호알칼리성 균주의 동정

이형재 ( Hyungjae Lee ),유지승 ( Ji Seung Yoo ),박영서 ( Young Seo Park ),배동훈 ( Dong Hoon Bai ) 한국산업식품공학회 2015 산업 식품공학 Vol.19 No.4

An alkalophilic microorganism, strain DK1122 producing an alkaline protease was identified. DK1122 was isolated from soil collected in central Korea. The strain DK1122 was Gram-positive, 0.7×2-4 μm in size, and its colony was yellowish white, The strain DK1122 was found to be spore-forming, catalase positive, oxidase positive, caseinolytic, and reduce nitrate to nitrite. The protease was produced aerobically on Horikoshi I agar medium (pH 9.0) with 1% (w/v) skim milk at 40°C for 24 h. Through 16S rRNA gene partial sequencing, the strain DK1122 had the 99.7% sequence similarity to 16S rRNA gene sequence of Bacillus pseudofirmus. Based on the biochemical and physiological properties as well as phylogenetic analysis, the isolated strain was named as Bacillus sp. DK1122. It is expected that Bacillus sp. DK1122 may be a promising candidate for a proudcer of an alkaline protease applicable to the food and detergent industries.

Assessment of clinical performance of an ultrasensitive nanowire assay for detecting human papillomavirus DNA in urine

Lee, HyungJae,Choi, Mihye,Jo, Minkyung,Park, Eun Young,Hwang, Sang-Hyun,Cho, Youngnam Elsevier 2020 Gynecologic oncology Vol.156 No.3

<P><B>Abstract</B></P> <P><B>Objective</B></P> <P>To evaluate whether HPV DNA in urine has potential advantages as an alternative biomarker for HPV-based cervical cancer screening.</P> <P><B>Methods</B></P> <P>Among patients with Cobas HPV test results, a total of 67 HPV-positive (n = 42) and -negative (n = 25) women who agreed to participate in this study were willing to provide paired cervical and urine samples, and we observed concordance between sample types from each patient in identifying HPV genotypes using the nanowire assay.</P> <P><B>Results</B></P> <P>We detected high-risk strains of HPV DNA in unprocessed urine specimens using polyethyleneimine-conjugated nanowires (PEI-NWs). Concordance for high-risk HPV (hrHPV) between paired urine and cervical samples was 90.4% (κ = 0.90; 95% CI: 0.80–100.00). The virological sensitivity and specificity for detection of HPV DNA from a small urine sample (200 μL) were 81.3% (κ = 0.83; 95% CI: 62.1–100.0) and 98.0% (κ = 0.83; 95% CI: 94.2–100.0) for HPV16 group, 100.0% (κ = 0.65; 95% CI: 100.0–100.0) and 95.3% (κ = 0.65; 95% CI: 90.1–100.0) for HPV18 group, and 96.4% (κ = 0.97; 95% CI: 89.6–100.0) and 100.0% (κ = 0.97; 95% CI: 100.0–100.0) for other hrHPV group, respectively.</P> <P><B>Conclusions</B></P> <P>The nanowire assay demonstrated excellent ability to identify HPV DNA from urine specimens. We observed an excellent agreement in the detection of high-risk HPV between paired urine and cervical samples, even with small urine sample volume.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanowire assay can detect HPV DNA in urine with high sensitivity and specificity. </LI> <LI> Non-invasive, urine-based HPV screening can increase cervical cancer effectiveness. </LI> <LI> HPV type-specific concordance rate between urine and cervical samples was over 90%. </LI> </UL> </P>