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Efficient Expression of Human Recombinant Proteins in E. coli Using Marinederived Signal Peptides
No full textWith the advancement of recombinant protein technologies, the biosimilar market has become highly competitive, and cost-effective mass production technologies for expired patent proteins are gaining attention. In this study, Erythropoietin that promotes red blood cell production, was selected as a target recombinant protein. We constructed two novel expression vectors containing marine-derived signal peptides from chitosanase and xylanase of marine microbes, along with a stabilization sequence, a Trigger Factor. The vectors were based on the pET-11a system and incorporated signal peptides to direct the expressed proteins outside the cells, facilitating purification without disrupting the cells. The vectors were introduced into E. coli BL21 and Rosetta strains, and recombinant protein expression was induced by IPTG. Low-temperature cultivation improved the expression of soluble proteins. Optimal conditions were determined for protein expression, and the proteins were purified using His-tag affinity chromatography. This study aims to develop a technology for the stable expression of human proteins using marine-derived signal peptides and is expected to contribute to the optimization of high-value biopharmaceutical production processes, improving efficiency and economic feasibility.1
1MW급 수평축 조류발전시스템 출력 특성 평가
No full text조류에너지 변환장치는 블레이드를 가진 로터와 발전기를 이용하여 조석 현상에 의해 발생하는 조류의 운동에너지를 전기에너지로 변환한다. 이는 유체의 흐름을 이용하여 터빈을 구동한다는 점에서 풍력터빈과 유사하지만, 출력 예측이 어려운 풍력과 달리 조류는 주기적인 해수의 흐름을 활용하므로 장기적인 출력 예측이 가능하고 안정적인 전력 생산이 가능하다. 본 연구에서는 1MW급 조류에너지 변환장치의 예비설계를 위한 유동 해석 및 통합 하중 해석을 수행하였다. 유동 특성을 평가하기 위해 3차원 RANS(Reynolds-Averaged Navier-Stokes) 해석을 수행하였으며, SST(Shear Stress Transport) 난류모델을 적용하고, 사면체 및 육면체 격자를 혼합하여 계산 격자를 구성하였다. 또한, Tidal Bladed를 이용한 통합 하중 해석을 통해 1MW 변환장치의 출력 성능 및 하중 특성을 분석하였다. 실제 크기의 변환장치는 울돌목 해역에 설치되었으며, 현장 실험을 통해 출력 성능을 검증하였다. 출력 계수는 수치 해석에서 33%, 실험 결과에서는 29.2%로 평가되었다.2
Interannual Variability of the Yellow Sea Bottom Cold Water simulated from a reanalysis product
No full textThe Yellow Sea Bottom Cold Water (YSBCW), a cold water mass in the bottom layer of the Yellow Sea, contributes significantly to maintaining high nutrient concentrations, supporting phytoplankton growth, and enhancing primary productivity, which are essential for the productivity and structure of regional marine ecosystems. This study produced a 13-year reanalysis dataset (2010–2022) to analyze the seasonal and interannual variability of the YSBCW. Numerical modeling was conducted using the Regional Ocean Modeling System (ROMS) with a horizontal resolution of 1/20° and 41 vertical layers. The model domain covered 117–150°E and 21–54°N. Atmospheric forcing was provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5, initial and boundary conditions by the Hybrid Coordinate Ocean Model (HYCOM), and tidal forcing by TPXO9. Data assimilation was performed daily using the Ensemble Kalman Filter (EnKF), assimilating sea surface temperature from the Operational Sea Surface Temperature and Ice Analysis (OSTIA) and temperature-salinity profiles collected by the Korea Institute of Ocean Science & Technology (KIOST), the National Institute of Fisheries Science (NIFS), the Korea Hydrographic and Oceanographic Agency (KHOA), and Argo floats. The reanalysis dataset reproduced the seasonal and interannual variability of the YSBCW and demonstrated its reliability through validation against observational data. Surface temperature analysis showed seasonal biases from -0.45°C in winter to 0.13°C in summer. The root mean square error (RMSE) values were 0.79°C in winter, the highest among all seasons, and 0.49°C in autumn, the lowest. The model captured the vertical distribution of the YSBCW well, although tidal effects and mixing were overestimated, resulting in stronger vertical mixing than that observed in the coastal regions. The annual YSBCW volume was calculated by determining the volume of water deeper than 30 m with a temperature below 10°C to analyze interannual variability. In August, the volume was largest in 2013 at 4 km³ and smallest in 2020 at nearly 0 km³. The average volume is around 3.5 km³, decreasing from 2019 to 2020 and then increasing from 2021 onwards. Spatially, the northern and eastern Yellow Sea showed relatively small changes in cold water distribution while the southern and western regions exhibited greater variability, with cold water below 10°C widely distributed in 2013 but almost absent in 2020. This reanalysis dataset reproduces the formation, dissipation, and interannual variability of the YSBCW. Future research will analyze how climate variability and atmospheric forcing influence the formation mechanisms and variability of the YSBCW.1
한국 연근해 선박정보 기반 수중소음의 시간 변동성 고찰
No full text선박 통행이 빈번한 항구 및 연안 지역에서는 1kHz 이하의 저주파 대역에서 선박 소음이 수중 소음의 주된 요인입니다. 본 연구는 SRH(Self-Recording Hydrophone)를 사용하여 선박 통행이 많은 연안에서 14일 동안 관측된 음향신호를 활용하여 1kHz 이하의 수중 소음을 분석하였습니다. 연구 지역은 대형 선박과 어선이 지속적으로 존재하는 항구로, 대형 선박에는 AIS 시스템이, 소형 어선(10톤 이하)에는 V-PASS 시스템이 설치되어 있습니다. V-PASS 시스템은
2013년에 도입되었으며, 모든 어선에 설치가 의무화된 자동 통신 장치로, 해양 사고에 신속하게 대응하기 위해 사용됩니다. 수중 소음 측정 기간 동안 AIS 및 V-PASS 시스템을 이용하여 대형 선박과 어선의 항해 정보를 수집하였습니다. 선박 소음 모델링 기법을 적용하여 관측된 수중 소음 데이터와 비교 분석을 수행하였으며, 모델링에서는 ROSS(1987) 경험식을 이용하여 개별 선박의 음원 준위를 계산하고, 수신기까지의 전파 손실은 거리 종속 음향 모델을 사용하여 계산하였습니다. 본 연구에서는 AIS 및 V-PASS 시스템을 기반으로 선박 소음 모델링 데이터와 실측 데이터를 비교 및 분석한 결과를 제시하고, 측정과 모델링 간의 차이에 대한 원인과 한계를 논의하며 이를 극복하기 위한 연구 방향을 제안합니다.2
Sublethal impacts of Hebei Spirit oil spill on the growth and reproductive physiology of the Pacific oyster Crassostrea gigas at Taean on the West Coast of Korea (2008–2010)
No full textFollowing the Hebei Spirit oil spill (HSOS) in December 2007, benthic organisms of the Taean coast on the west coast of Korea were heavily affected. A month after HSOS, the alkyl PAHs in the oyster body elevated to 13,500 ng/g dry wt, although it dropped to 5335 ng/g dry wt in December 2008, and returned to the levels before the accident (547–858 ng/g dry wt) by 2010. In 2008 spring, the damaged oysters exhibited deteriorated growth and reproduction, exhibiting signs of physiological stress. However, a year after the accident, oysters exhibited signs of recovery from the stresses. Gonad maturation, reproductive effort, and carbohydrate content recorded in 2010 were comparable to the levels in 2009 and the levels in undamaged oysters. Our study suggested that the Pacific oysters recovered from the HSOS stresses within a year, although long-term monitoring of oyster health must be carried out to ascertain the recovery.11Nsciescopu
The enzymatic and transcriptional adverse effects of hull in-water cleaning discharge on juvenile rockfish (Sebastes schlegeli)
No full textThe hull in-water cleaning (IWC) process creates chemical contaminants, including antifouling paint particle mixtures that are directly discharged into the coastal environment. Recent attention has also been paid to the international regulation of ship hull cleaning discharges in environmental media. However, few studies have investigated the adverse effects or toxic pathways on resident marine species. In this study, we evaluated the chemical concentration of IWC discharge in situ and its toxic effects on juvenile rockfish ( Sebastes schlegeli), a major coastal fishery resource, using enzymatic and transcriptomic studies. Zinc (8.05 f 0.96 to 189.96 f 47.76 mu g/L) was the most abundant substance in IWC discharge, followed by copper (0.87 f 0.19 to 1.97 f 0.60 mu g/L). No mortality was observed after 7 days of exposure in any experimental group; however, reactive oxygen species and acetylcholinesterase activity varied in juvenile rockfish exposed to the highest concentration of IWC discharge (10-fold-diluted IWC discharge). The immune and detoxification systems in juvenile rockfish exposed to IWC discharge were also significantly affected in juvenile rockfish exposed to 10-fold-diluted IWC discharge (zinc: 189.96 f 47.76 mu g/L, copper: 1.97 f 0.60 mu g/L). The expression of genes related to oxidative stress, including Cu/Zn-SOD, GST, and CAT, increased significantly in fish in all the exposure groups. Specifically, brain transcriptomic analysis revealed disturbances in the nervous system and homeostatic processes. Although lethal toxicity was not significantly affected, these findings indicate the potential hazard posed by sub-lethal concentrations of IWC discharge to juvenile fish, which are at a high-level in the food chain. Our enzymatic and transcriptomic results showed that Zn-dominant IWC discharge exposure may cause neuronal and immune toxicity in marine fish species, providing relevant insights into the management of hull IWC discharge to protect coastal ecosystems against chemical contaminants.11Nsciescopu
Spatial characteristics of mesozooplankton communities and environmental drivers in the western Indian Ocean along 65°E meridional line
No full textThe western Indian Ocean is influenced by a variety of oceanic currents, which play a crucial role in shaping the spatial distribution of mesozooplankton communities. To understand the spatial characteristics of mesozooplankton community structure, MultiNet was used to sample mesozooplankton in the western Indian Ocean during May-June 2023. Depth-discrete mesozooplankton samples were collected during the daytime from surface to 1,000 m depth at four stations (19°S, 08°S, 02°S, and 02°N) along the 65°E meridional line. Four distinct types of mesoscale physical characteristics were observed: (1) the South Equatorial Current (SEC) (19°S), (2) the Seychelles-Chagos Thermocline Ridge (SCTR) (08°S), (3) the South Equatorial Counter Current (SECC) (02°S), and (4) the South-west Monsoon Current (SMC) (02°N). At 08°S, SCTR was characterized by a shoaling of 20℃ isotherm. Lower-saline water was observed in the surface layer at 19°S and 02°N, while the surface layer at 02°N exhibited the highest salinity. Chlorophyll-a concentrations in the subsurface chlorophyll maximum (SCM) were significantly higher at 08°S and 02°N than at 19°S and 02°S. A significant proportion (89-98%) of mesozooplankton abundance was concentrated between the mixed layer and thermocline, suggesting that this zone may provide a favorable habitat for mesozooplankton due to enhanced food availability. Small copepods (2 mm) were dominant across all stations. Total mesozooplankton abundances were higher at 08°S (1,473 inds./m3) and 02°N (1,441 inds./m3) than at 19°S (954 inds./m3) and 02°S (827 inds./m3), with a particularly high abundance of copepods at 08°S (1,033 inds./m3) and 02°N (994 inds./m3) compared to 19°S (683 inds./m3) and 02°S (530 inds./m3). Species richness was higher at stations between 08°S and 02°N (79-82) compared to 19°S (60). Two cluster analyses revealed distinct patterns in the mesozooplankton community structure. One analysis, based on sampling depth, showed that mesozooplankton communities were grouped according to depth (i.e., mixed layer-thermocline versus below thermocline-1,000 m), which likely reflects the vertical stratification driven by both physical (temperature gradients) and biological (feeding) processes. A second cluster analysis, based on abundance at each sampling depth, indicates that communities at stations between 08°S and 02°N (Group A) consistently differed from 19°S (Group B) across sampling depths. BIO-ENV analysis indicated that mean temperature at each depth was the most important environmental factor driving the spatial variations in distribution characteristics and structure of the mesozooplankton communities (p<0.05, r=0.801). These results suggest that horizontal and vertical spatial variations in mesozooplankton communities in the western Indian Ocean are influenced by depth-dependent hydrological parameters, such as temperature and chlorophyll-a, and regional heterogeneity of oceanic currents across latitudes.1