음의 상관관계가 있는 Grating 주기의 랜덤 변이가 DFB 레이저 특성에 미치는 영향

학위논문(석사)--亞洲大學校 大學院 :電子工學科,2000textMaste

Dynamics of Host-Driven Viral Community and Auxiliary Metabolic Genes by latitudinal gradient

Auxiliary metabolic genes (AMGs) encoded by viruses are pivotal in modulating host metabolism and driving microbial biogeochemical cycles across diverse ecosystems. AMGs play a crucial role in processes such as nutrient cycling, carbon fixation, and energy flow, making them key components in regulating ecosystem functions. Bacteriophages often carry AMGs, empowering them to boost their host's metabolism or enhance virus fitness. Understanding the factors influencing AMG analysis within viral communities is essential for elucidating the complex interactions between viruses, hosts, and their environments. To explore the ecological diversity and metabolic functions of viral communities, we analyzed AMGs across latitudinal gradients, focusing on the Arctic (Svalbard, Norway), Temperate (Tongyeong, South Korea), and Tropical (Chuuk, Micronesia) regions using metagenomic analysis. Our findings revealed that bacteriophage communities in the Temperate and Tropical regions exhibited similar AMG analysis, particularly associated with photosynthetic electron transport and productivity. In contrast, viral communities in the Arctic region displayed distinct AMG analysis, focusing on genes involved in the biosynthesis of unsaturated fatty acids, a crucial process for cold adaptation. These differences likely reflect the selective pressures imposed by varying environmental conditions, such as temperature and light availability. This study reveals the adaptive roles of viruses in modulating host metabolism through distinct AMG analysis across different ecosystems. It emphasizes the importance of AMGs in microbial biogeochemical processes and sets the stage for future research on their global distribution and ecological significance.2

Ecological interaction between bacteriophages and bacteria community during the early white night and mid-summer in Sub-arctic Kongsfjorden bay of Svalbard (Norway)

Marine viruses including viruses and phages infect various marine organisms. However, little is known about the diversity of marine viruses and their relationships with their hosts in marine environments. This study investigated the co-occurrence between marine DNA bacteriophages (phages) and the bacteria community in the sub-Arctic area using metagenomics tools in the Kongsfjorden Bay of Svalbard (Norway) in April and June 2018. Among all identified marine viruses, 48-81% were phages involving the families Myoviridae, Siphoviridae, and Podoviridae (in Caudoviriales) as the common groups (order levels). In addition, Puniceispirillum phage HMO-2011 was the most dominant at 7.61% in April, and Puniceispirillum phage HMO-2011 and Pelagibacter phage HTVC008M was the most dominant at 3.32% and 3.28%, respectively, in June. In the bacteria community, Gammaproteobacteria was 58% of the prevalent group (class level) and Eionea flava (14.3%) and Pseudomonas sabulinigri (12.2%) (Gammaproteobacteria) were the most predominant taxa in April, but Alphaproteobacteria showed an absolute predominance of 87%, and Sulfitobacter profundi and Loktanella acticola (Alphaproteobacteria) were the most predominant taxa at 51.5% and 32.4%, respectively, in June. In species- specific relationship between bacteria and phages, Puniceispirillum phage HMO-2011 and Synechococcus phage S-SSM7 was stronger correlated with Eionea flava (r=0.764, p<0.01) and Sulfitobacter profundi (r=0.842, p<0.01), respectively. This relationship between phages and bacteria community may be caused by changes in response to environmental changes, such as increases in water temperature and light intensity. Taken together, these findings are particularly relevant considering the anticipated impact of phages-induced bacterial control mechanisms on the Sub-Arctic Kongsfjorden ecosystem.2

Algal Contribution to the Occurrence of Refractory Organic Matter in Lake Paldang, South Korea: Inferred from Dual Stable Isotope (13C and 15N) Tracer Experiment

While a fairly large amount of organic matter is produced daily via phytoplankton photosynthesis in Lake Paldang, South Korea, knowledge of the role of algal-derived organic matter (OM) as a refractory OM source is not adequate. To understand the contribution of algal-derived OM to the refractory pool, biodegradation experiment and KMnO4 oxidation experiment were conducted for 60 days using 13C and 15N labeled natural phytoplankton assemblage. The assemblage was collected from Lake Paldang on May 20, 2010. The photosynthetically produced total organic carbon (TO13C), particulate organic carbon (PO13C), and particulate nitrogen (P15N) remained at 26%, 20%, and 17% of the initial concentrations, respectively, in the form of non-biodegradable organic matter. In addition, 12% and 38% of PO13C remained after KMnO4 treatment on Day 0 and 60, respectively. These results indicate that photosynthetic products could be an important source of refractory organic matter after microbial degradation. Moreover, the microbially transformed algal-derived OM could contribute to the oxidation rate of the chemical oxygen demand. 효과적인 물환경관리계획을 수립하기 위해서는 다양한 기원의 유기물이 난분해성 유기물 농도 증가에 영향을 줄 수 있는지 여부를 파악하는 것이 중요하다. 특히 상당량의 광합성 산물은 식물플랑크톤에 의해 매일 생성되고 있지만, 이들이 수계 내 난분해성 유기물에 기여하는지에 대한 정보는 부족하다. 본 연구에서는 13C 및 15N 추적자 첨가 실험을 통해 조류기원 유기물이 생분해 (60일, 암배양) 및 산화제 (과망간산칼륨) 처리 후 분해되지 않고 잔존하는지 여부를 확인하였다. 생분해 실험 결과 광합성을 통해 생성된 총 유기탄소 (TO13C), 입자성 유기탄소 (PO13C), 입자성 질소 (P15N)는 각각 26%, 20%, 17%가 비 생분해성 유기물로 잔존하였다. 또한 상당량의 PO13C가 과망간산칼륨에 의해 산화되지 않고 잔존하였다 (초기: 12%, 60일 암배양 후: 38%). 이는 미생물에 의해 사용된 후 남아있는 조류 기원 유기물이 난분해성 유기물에 기여할 수 있음을 의미 한다. 또한 미생물에 의해 변형된 조류기원 유기물의 양은 COD 산화율 및 유기물 지표 간 격차에 영향을 줄 것으로 사료된다.22Nkc