• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1493-1499
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• 2013

A novel radiation-resistant Filobasidium sp. yeast strain was isolated from seawater. Along with this strain, a total of 656 yeast isolates were purified from seawater samples collected from three locations in the West Sea of Korea and assessed for their radiation tolerance. Among these isolates, five were found to survive a 5 kGy radiation dose. The most radiation-resistant strain was classified as Filobasidium sp. based on 18S rDNA sequence analysis and hence was named Filobasidium RRY1 (Radiation-Resistant Yeast 1). RRY1 differed from F. elegans, which is closely related to RRY1, in terms of the optimal growth temperature and radiation resistance, and was resistant to high doses of ${\gamma}$-ionizing radiation ($D_{10}$: 6-7 kGy). When exposed to a high dose of 3 kGy irradiation, the RRY1 cells remained intact and undistorted, with negligible cell death. When these irradiated cells were allowed to recover, the cells fully repaired their genomic DNA within 3 h of growth recovery. This is the first report in which a radiation-resistant response has been investigated at the physiological, morphological, and molecular levels in a strain of Filobasidium sp.

• Ocean and Polar Research
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• 제25권4호
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• pp.625-631
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• 2003

While phytoplankton diversity and productivity in the Southern Ocean has been widely studied in recent years, most attention has been given to elucidating environmental factors that affect the dynamics of micro-plankton (mainly diatoms) and nano-plankton (mainly Phaeocystis antarctica). Only limited effects have been given to studying the occurrence and the potential risks associated with the blooming of dinoflagellates in the relevant waters. This study focused on the appearance and toxicological characteristics of a toxic dinoflagellate, Alexandrium tamarense, identified and isolated from the Drake Passage in a research cruise from November to December 2001 The appearance of A. tamarense in the Southern Ocean indicates the risk of a paralytic shellfish poisoning (PSP) outbreak there and is therefore of scientific concern. Results showed that while the overall quantity of A. tamarense in water samples from 30meters below the sea surface often comprised less than 0.1% of the total population of phytoplankton, the highest concentration of A. tamarense (20 cells $L^{-1}$) was recorded in the portion of the Southern Ocean between the southern end of South America and the Falkland Islands. Waters near the Polar Front contained the second highest concentrations of 10-15 cells $L^{-1}$. A. tamarense was however rarely found in waters near the southern side of the Polar Front, indicating that cold sea temperatures near the Antarctic ice does not favor the growth of this dinoflagellate. One strain of A. tamarense from this cruise was isolated and cultured for further study in the laboratory. Experiments showed that this strain of A. tamarense has a high tolerance to temperature variations and could survive at temperatures ranging from $5-26^{\circ}C$. This shows the cosmopolitan nature off. tamarense. With regard to the algal toxins produced, this strain of A. tamarense produced mainly C-2 toxins but very little saxitoxin and gonyailtoxin. The toxicological property of this A. tamarense strain coincided with a massive death of penguins in the Falkland Islands in December 2002 to January 2003.

• 한국어병학회지
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• 제36권2호
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• pp.229-238
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• 2023

In this study, the correlation between clinical changes and RSIV genome copy number was investigated to determine the quantitative criteria for the characteristics of RSIV infection. The rock bream (Oplegnathus fasciatus) was intraperitoneally injected with three different doses (1.0×10¹, 1.0×10³ and 1.0×10⁵ viral genome copies/fish) as low, medium, and high doses, respectively. The clinical signs (spleen enlargement, death) observation and real-time PCR were conducted at 5, 10 and 14 days post-injection. During the experiment, spleen index as a quantitative indicator for spleen enlargement was continuously increased in the medium- (up to 2.26) and high-dose (up to 4.99) challenge groups, respectively. Notably, when the spleen index was over 1.5, 2.0, 2.5 and 3.0, a positive correlation was revealed with average viral genome copy numbers of 2.51, 3.37, 4.97 and 5.43×10⁷ viral genome copies/mg, respectively. Moreover, the threshold of spleen index over 1.5 was 1.0×10⁶ viral genome copies/mg, while the thresholds of spleen index over 2.0 and dead was 2.51×10⁷ viral genome copies/mg and the thresholds of spleen index over 2.5 and 3 was 3.98×10⁷ viral genome copies/mg. These findings suggest the possibility of quantitatively analyzing the characteristics and development process of RSIV infection.

• 한국식품영양과학회지
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• 제44권1호
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• pp.35-43
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• 2015

본 연구에서는 노루궁뎅이 버섯균사체를 비타민나무 잎에 배양하여 조제한 노루궁뎅이 버섯균사체-비타민나무 발효물 열수 추출물이 생체고분자의 산화적 손상과 세포사멸을 보호할 수 있는지를 관찰하였다. 노루궁뎅이 버섯균사체-비타민나무 발효물의 항산화 활성을 DPPH radical, ABTS radical, peroxyl radical 소거활성 측정을 통해 알아보았다. 그 결과 노루궁뎅이 버섯균사체-비타민나무 발효물을 처리한 DPPH radical 소거활성은 $500{\mu}g/mL$ 농도에서 65.06%, ABTS radical 소거활성은 $50{\mu}g/mL$ 농도에서 98.83%, peroxyl radical 소거활성은 $100{\mu}g/mL$ 농도에서 44.03%로 높은 항산화 활성을 나타내었다. 노루궁뎅이 버섯균사체-비타민나무 발효물은 DNA의 산화적 손상을 효과적으로 억제하였다. 노루궁뎅이 버섯균사체-비타민나무 발효물 역시 사람의 혈청단백질과 Cu,Zn-SOD의 산화적 손상을 억제하였다. 세포에 $H_2O_2$를 처리하였을 때 세포생존율에 비하여 발효물을 $100{\mu}g/mL$ 농도로 전 처리한 세포생존율은 21.59% 높게 증가되었다. 또한 발효물을 $50{\mu}g/mL$ 농도로 처리했을 경우 세포 내 ROS의 축적이 유의적으로 감소되었다. 따라서 노루궁뎅이 버섯균사체-비타민나무 발효물은 항산화 활성뿐만 아니라 산화적 스트레스에 의해 야기되는 세포 독성에 대한 보호 작용이 뛰어난 것으로 사료된다.

• 한국어류학회지
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• 제31권4호
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• pp.201-207
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• 2019

수온은 양식어류의 생존에 영향을 미치는 가장 주요한 환경 요인이며, 겨울철 급작스런 수온 하강은 양식어류의 질병과 집단폐사 발생의 요인이 되기도 한다. 본 연구는 겨울철 수온 하강으로 인해 빈번하게 폐사가 발생하고 있는 말쥐치의 양식관리를 위한 기초자료로 활용하기 위해 말쥐치의 하한수온내 성범위, 산소소비율, 혈액학적 및 조직학적 반응을 조사하였다. 수온 5℃에서 노출 3일째, 수온 6℃에서는 노출 4일째 모두 폐사하여 말쥐치의 저수온에 대한 반수치사 하한수온은(LT₅₀) 6.97℃ (6.69~7.27℃)였다. 산소소비율은 수온 하강에 따라 감소하여 수온 간 유의한 차이(p<0.05)를 나타내었다. 혈액내 활성산소 소거효소인 SOD활성도는 대조구 10℃에 비해 수온 6℃에서 유의하게 상승하였다(p<0.05). 반면 CAT는 실험수온 간에 유의한 변화를 나타내지 않았다(p>0.05), 삼투질농도는 대조구와 실험수온 간 유의한 차이는 나타나지 않았다(p>0.05). 코티졸은 대조구에 비해 수온 하강에 따라 증가하였으며 수온 간 유의한 차이를 나타내었다(p<0.05). 간의 조직학적 변화는 혈관내 혈구의 감소, 간세포의 공포화와 간세포 핵의 응축, 췌장 외분비 선세포의 위축 및 효소원과립들이 감소하였다.

• 한국제4기학회지
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• 제18권2호통권23호
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• pp.67-73
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• 2004

Dissected erosional surfaces are widely distributed in the western part of Korea (e.g. Icheon, Chungju, Jecheon, Seosan). The deposits with thickness of less than 2m occur on the smooth bedrock surface are composed of poorly sorted subangular gravels with less than 20cm diameter. However, only weathered mantle of granites without the gravel layer are observed at some outcrops. The results of grain size analysis of deposits of Icheon district revealed that the characteristic of the gain size distribution is very similar with the results of sheetflood deposits presented by Blair (1999) in the Death Valley. Loess layer with buried soil layers of MIS7 covers the sheetflood deposits. The loess layer implies that the sheetflood deposits occurred before MIS7 based on the typical Loess sequences presented by Naruse et al.(2003). On the other hand, the climate of Korean Peninsula in MIS2 was very dry and cold (Yoon and Hwnag, 2003) by pollen analysis. This is because Yellow Sea was completely emerged during the MIS2(e.g. Sau\ito, 1998). So, it is thought that the climate in Korean Peninsula of not only MIS2 but also other glacial ages such as MIS8 was similar with present Mongolian climates. Tanaka et al.(2005) pointed out that Hortonian overlandflow occurs in grass vegetated granite basin in Mongolia. Therefore, dissected piedmont gentle slopes in the western Korea were possibly formed by sheetflood erosion during probably MIS8 as pediment widely distributed in Mongolia.

• 한국해양학회지
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• 제26권4호
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• pp.350-357
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• 1991

조간대에 서식하는 고둥류인 좁쌀무늬총알고동, 총알고동, 대수리 등 3종에 대한 유류오염과 유처리제를 이용한 정화작업의 영향을 조사하기 위한 실험을 실시하였다. 라뷰안 원유, 듀바이 원유, 벙커 C유를 실험 생물에 각각 직접 접촉시켰으며, 또한 1 시간 노출시킨 후에 농축형 유처리제로 세척하였다. 원유에 접촉시킨 고동류는 96시간 내에 모두 처사하였으며, 라뷰안 원유가 듀바이 원유보다 높은 독성을 보였다. 벙커 C 유에는 총알고동류가 대수리보다 민감한 반응을 보였으며, 원유 접촉시보다는 서서히 독성효과가 나타났다. 높은 농도의 유처리제를 이용한 전화작업은 고동류에게 치명적 인 영향을 주었으며, 낮은 농도에서도 총알고동류에게 유해한 영향을 주었다. 대수리 는 분산된 유류에 노출될 경우 250 ppm 이하의 농도에서는 도피행동을 보였다. 유류오 염과 유처리제를 이용한 정화작업은 고동류의 흡착기능을 저해하여 물리적인 힘에 의 해 서식지 이탈을 유발시킬 수 있을 것으로 보인다.

• 수산해양기술연구
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• 제55권2호
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• pp.145-151
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• 2019

The coastal composite fishery has the highest rate of around 30.0% in registered fishing vessels of Korea for the last three years. The risk analysis for the fisher's safety of coastal composite fishing vessels was conducted to serve as a basic data for improving the healthy and safe working environment of fisher using fisher's occupational accidents of the national federation of fisheries cooperatives (NFFC) from 2016 to 2018 (n = 1,105). As a result, the occupational accident occurrence rate of coastal composite fishery was 3.76% in all industries, 7.8 times the rate of that. In addition, death and missing rate was found to have a serious level management to 10.10‱. Among the accidents, 76.0% occurred at sea. The slipping, others and contact with machinery or fishing gear occurred more frequently in order in the frequency of accident occurrence pattern. In the risk assessment using frequency and severity, slipping, contact with machinery and others showed high risk during fishing. The results are expected to contribute to identification and assessment of safety hazard occurred in coastal composite fishing vessels.

• Ocean and Polar Research
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• 제36권2호
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• pp.135-143
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• 2014

The effect of salinity on the survival, oxygen consumption and blood physiology of Korean rockfish Sebastes schlegelii (body weight $97.4{\pm}1.7g$, $mean{\pm}SD$) was investigated at nine different salinities of 33.4 (control), 33.1, 32.8, 32.2, 31.0, 28.7, 23.9, 14.5 and 3.8 psu, respectively. Survival and blood physiology were measured at each salinity in two separate trials of 96 and 24 hr duration, respectively. Oxygen consumption rate (OCR) was determined at stepwise salinity exposure ($33.4{\rightarrow}33.1{\rightarrow}32.8{\rightarrow}32.2{\rightarrow}31.0{\rightarrow}28.7{\rightarrow}23.9{\rightarrow}14.5{\rightarrow}3.8$ psu) with an interval of 24 hr for each salinity. No death of fishes were observed in the range of 33.4 to 14.5 psu, but the survival rate was reduced to 26.7% at 3.8 psu after 96 hr. The OCRs were not significantly different in the range 33.4 to 28.7 psu (p > 0.05), but significantly increased until 14.5 psu and then drastically decreased at 3.8 psu compared to the control (p < 0.05). The concentrations of plasma $Na^+$ and $Cl^-$ were significantly lower in fish exposed at 3.8 psu compared to the control (p < 0.05). The results of this study provide evidence that S. schlegelii exposed to concentrations below 23.9 psu show significant physiological responses to tolerate salinity changes under the experimental conditions we established.

• 한국패류학회지
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• 제32권2호
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.