실리카 나노입자의 분산조건에 따른 입도분포 변화 및 A549 세포독성

이한들(Han dule Lee),박주영(Ju young Park),박광식(Kwang sik Park) 대한약학회 2017 약학회지 Vol.61 No.6

Size and/or size distribution is a very important factor in the cellular toxicity test of nanoparticles. Therefore, it is necessary to fulfill the requirement of standardized dispersion protocol when toxicity potencies of different types of nanoparticles are compared. In this study, different conditions including ethanol pre-wetting, concentration of bovine serum albumin in media, and measurement instruments were investigated to see the impact on the dispersity of silica nanoparticles after calibrated sonication. As results, the concentration of bovine serum albumin seemed to mostly influence the dispersion of silica nanoparticles. No significant difference was shown in cytotoxicity of cultured A549 cells among silica (SiO₂), zinc (ZnO), silver (Ag), ceria (CeO₂) and titanium (TiO₂) nanoparticles when they were dispersed by same amount of energy after calibrated sonication.

Novel Insights into Agar Metabolism in Marine Heterotrophic Bacteria

파티라자 무디얀셀라게 둘리브 파티라자(Pathiraja Mudiyanselage Duleepa Pathiraja ),최인걸(In-Geol Choi) 고려대학교 생명자원연구소 2022 생명자원연구 Vol.30 No.-

대형 홍조류는 해양 생태계에서 해양 종속영양세균을 위한 풍부한 서식지를 제공하며, 한천은 대형 홍조류를 이루는 주요 구조적 다당류이다. 한천을 단일 탄소원으로 사용할 수 있는 해양 한천분해세균은 개방된 연안 해역에서 해양 초식 동물의 내장에 이르기까지 다양한 해양 환경에 분포한다. 한천분해세균에서의 한천의 해중합은 탄수화물 활성 효소(CAZymes)의 조합을 통해 이루어 진다. 한천분해세균의 유전체 구조에 대한 다양한 연구에서 이러한 탄수화물 활성 효소를 암호화하고 있는 유전자가 다당류 이용유전자좌(PUL)를 이루고 있음이 밝혀졌다. 한천 가수분해 효소(agarases)는 다음과 같이 분류되어질 수 있다. β-한천분해효소(GH16, GH50, GH86 및 GH118), α-한천분해효소(GH96), 네오아가로바이오스 가수분해효소(GH117) 및 한천분해 β-갈락토시데이스(GH2). 서로 다른 GH 계열에 속한 한천 가수분해효소들은 분자수준 기능, 구조 요소 및 촉매 메커니즘에 있어 고유한 특성을 나타낸다. 한천의 주요 성분 중 하나인 L-AHG는 희귀한 단당류이며, 그 대사 경로는 해양 한천분해세균에서만 발견되어 있다. 한천분해 시스템에 대한 최근의 연구들은 해양 종속영양세균이 가진 한천분해 경로의 보편적인 한천분해 효소 레퍼토리와 이의 진화를 보여주는 서열분석 데이터에 초점을 맞추고 있다. 또한, 올리고당의 수송 메커니즘과 PUL 유전자의 전사 조절을 이해하는 데에도 점점 더 많은 관심이 기울어지고 있다. 이 리뷰에서 우리는 한천 분해와 관련된 해양 종속영양세균의 유전체 구조에서부터 한천 분해의 대사 과정, 한천 가수분해 효소의 구조 및 기능 분석까지의 포괄적인 개요를 다룰 것이다. Agar is a key structural polysaccharide of red macroalgae which provides a rich habitat for marine heterotrophic bacteria in marine ecosystems. Marine agarolytic bacteria, that can use agar as the sole carbon source, are distributed in diverse marine environments from open coastal waters to the gut of marine herbivores. Agarolytic bacteria employ a combination of carbohydrate-active enzymes (CAZymes) for the depolymerization of agar. Extensive studies on the genomic architecture of the agarolytic bacteria suggested that genes encoding these CAZymes are arranged in polysaccharide utilization loci (PUL). Agar hydrolyzing enzymes (agarases) are categorized into; β-agarase (GH16, GH50, GH86, and GH118), α-agarase (GH96), neoagarooligosaccharide hydrolase (GH117), and agarolytic β-galactosidase (GH2). The molecular functionality, structural elements, and catalytic mechanisms of agarases belonging to different GH families show unique characteristics. L-AHG, one of the main constituents in agar, is a rare monosaccharide and its metabolic pathway is exclusively found in marine agarolytic bacteria. Recent trends in the agarolytic systems are mostly focused on the sequence data to visualize the universal agarolytic enzyme repertoire and the evolution of the agarolytic pathway in marine heterotrophic bacteria. In addition, increasing attention is paid to understanding the oligosaccharide transport mechanisms and transcriptional regulation of genes in PUL. In this review, we will cover a comprehensive overview of genomic architecture, structural and functional analysis of agar hydrolyzing enzymes, and agar metabolism in marine heterotrophic bacteria.

Insights Into Emissions and Exposures From Use of Industrial-Scale Additive Manufacturing Machines

Stefaniak, A.B.,Johnson, A.R.,du Preez, S.,Hammond, D.R.,Wells, J.R.,Ham, J.E.,LeBouf, R.F.,Martin, S.B. Jr.,Duling, M.G.,Bowers, L.N.,Knepp, A.K.,de Beer, D.J.,du Plessis, J.L. Occupational Safety and Health Research Institute 2019 Safety and health at work Vol.10 No.2

Background: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. Methods: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. Results: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from $4.1{\times}10^{10}$ (Ultem filament) to $2.2{\times}10^{11}$ [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (${\mu}g/min$) ranged from $1.9{\times}10^4$ (acrylonitrile butadiene styrene and polycarbonate) to $9.4{\times}10^4$ (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open ($2.3{\times}10^{10}number/min$) than when the lid was closed ($1.5-5.5{\times}10^9number/min$); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. Conclusion: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial-scale AM process emissions and exposures.

Insights Into Emissions and Exposures From Use of Industrial-Scale Additive Manufacturing Machines

A.B. Stefaniak,A.R. Johnson,S. du Preez,D.R. Hammond,J.R. Wells,J.E. Ham,R.F. LeBouf,S.B. Martin Jr.,M.G. Duling,L.N. Bowers,A.K. Knepp,D.J. de Beer,J.L. du Plessis 한국산업안전보건공단 산업안전보건연구원 2019 Safety and health at work Vol.10 No.2

Background: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. Methods: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. Results: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from 4.1 1010 (Ultem filament) to 2.2 1011 [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (mg/min) ranged from 1.9 104 (acrylonitrile butadiene styrene and polycarbonate) to 9.4 104 (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open (2.3 1010 number/min) than when the lid was closed (1.5e5.5 109 number/min); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. Conclusion: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial- scale AM process emissions and exposures.