• Parasites, Hosts and Diseases
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• 제28권4호
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• pp.221-234
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• 1990

The present study was performed to know the epidemiological statug of echinostomiasis in the Chungju Reservoir and upper streams of Namhan River, together with an experimental study on the life history o( Echinostoma hortense. The stool specimens of 169 inhabitants and 473 junior high school students from 5 different villages revealed 3(0.5%) echinostomatid egg Positive cases. E. hortense adult worms were recovered from one patient after a treatment and purgation. For the other two patients, it was presumed that one had 2. hortense and another E. cinetorchis infection, based on the morphology of eggs. Five kinds of freshwater snails(168 Radix auricularia coreane, 534 Physa arutp, 144 Hippeutis cnntori, 56 Cipcngopaludina chinensis malleata and 125 Semiiulcospira nediila glebus) examined for the cercariae of echinostomes showed negative results. Ten kinds of freshwater fishes examined for E. herten-'emetacercariae revealed positive rates as Misgurnus anguillicaudatus 40.5%, Odentobutis obscura interrupta 20.3%, Moroco onycephalus 3.9%, and Coreoperca hawamebari 2.0%. In the experimental study, the metacercariae of E. horlense were infected to rats, eggs were collected from adult worms and cultivated, and miracidia were obtained. The miracidia were artificially infected to freshwater snails (R. auricularia), and cercarial shedding was studied. It was revealed that, when the snails were kept at a low temperature ($24^{\circ}C$), only 523 cercariae (on average) were produced during 24 hrs, while they were at a high temperature ($30^{\circ}C$), as many as 9, 990 cercariae (on average) were shed during the same time. The experimental infection of E. hortense cercariae to freshwater fishes was successful in 0. obscura interrupta 52.0%, M. anguillicaudatus 30.3%, C. kawamebari 27.0%, Cobitis lutheri 15.0%, M. cxycephazus 7.3%, Pseudogobio esocinus 4.3%, Squalidus cereanus 2.0%, Zccco platypus 1.3%, and Pungtungia herzi 1.3%. However, infection was not successful to snails, C. chinensis. It has been proved that the Chungju Reservoir and upper streams of Namhan riyrr are endemic areas of echinostomiasis, especially of E. horfense, and snails such as R. auritulerie coreana and fishes such as O. obscura interrupts, M. gnguillicgudgtus, and others are taking the role of 6rst and second intermediate hosts, respectively.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.335-336
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• 2006

오늘날 선박의 음용수에 대한 화학적/생물학적 조성은 말할 나위 없이 중요하다. 이 디자인은 선박의 fresh water treatment에 필요한 개별 장치를 제작사가 하나의 UNIT로 제작함으로써 설치 지침 등에 오류가 없도록 하고 신속한 TOTAL A/S가 가능함은 물론 물류 비용 절감 및 제작 기간이 단축되는 효과를 기대할 수 있게 된다.

• 한국패류학회지
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• 제14권2호
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• pp.167-172
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• 1998

As a preliminary study, effects of environmetal pollutants on propagation of freshwater microalgae, Cryptomonas ovata and feeding rate of Corbicula leana were investigated at 20${\pm}$1$^{\circ}C$, over 20 days after treatment of pollutants, glucose, complex fertilizer and NH4Cl. Number of C. ovata in control group was increased from 38${\times}$104 cell/ml to 1.910${\times}$104 cell/ml after 20 days cultivation in Sorokin-Krauss medium. Increments of cell number in experimental groups treated with glucose, complex fertilizer and NH4Cl were higher than that of control group. The higher propagation rate of C.ovata was observed when 30 mg/l of glucose treated, 120 mg/l of complex fertilizer treated, and 4 mg/l of NH4Cl treated, compared with other concentrations in each pollutant treated group. The feeding rates of large size group of C. leana which fed with a living organism, C. ovata in each experimental group were higher than small size group, and slightly reduced with the increase of pollutant concentrations. The feeding rates were not significantly different between any concentrations of the pollutant, and among experimental groups treated with glucose, complex fertilizer and NH4Cl.

• 생태와환경
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• 제56권1호
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• pp.94-103
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• 2023

휴면포자와 같은 남조류의 휴면세포는 남조류의 초기발생 및 대발생의 중요한 씨앗세포이다. 이러한 중요성으로 인해 퇴적층에 존재하는 휴면세포를 분리하기 위해서 다양한 방법들이 시도되었다. Ludox는 해양퇴적물의 세포분리에 주로 활용되는 용액이지만 담수에서는 정확한 사용법을 찾기 어렵다. 본 연구에서는 가장 많이 사용되는 두 가지 Ludox방법(퇴적물 직접처리, 퇴적물 증류수 현탁처리)을 비교하고, 담수 퇴적물에서 남조류 휴면세포의 분리 및 유전자 증폭 효율이 높은 방법을 제안하였다. 퇴적물에서 발견된 휴면세포는 대부분 염주말목의 휴면포자로써 Dolichospermum, Cylindrospermum, Aphanizomenon의 휴면포자 형태와 유사하였다. 퇴적물을 증류수에 현탁하여 처리한 시료보다 퇴적물 그대로 사용한 시료에서 20배 더 많은 휴면포자가 발견되었으며 증류수로 현탁된 퇴적물에서는 분리되지 않은 세포가 대부분 pellet 퇴적물 표층에서 발견되었다. Ludox를 통해 층 분리된 휴면포자는 수층의 특정 깊이에서 밀집하기보다는 주로 상층과 하층에 넓게 퍼져있었다. 퇴적물을 그대로 사용한 시료에서 mibC, Geo, 16S rDNA 유전자 모두 증폭산물이 확인되었으나 퇴적물을 증류수로 현탁한 시료에서는 모든 유전자의 증폭산물이 발견되지 않았다. 따라서 담수 퇴적물에서 남조류의 휴면세포를 분리하는 경우에는 5~10 g의 퇴적물을 전처리 없이 그대로 사용하며, 퇴적물량 4배 부피의 Ludox를 첨가할 때 세포 분리 및 유전자 증폭 효율이 높았다. 본 연구에서 제시하는 Ludox 처리방법은 담수퇴적층에 존재하는 남조류 휴면세포를 분리하기 위한 방법으로써 다른 생물군에서는 동일한 효율이 나타나지 않을 수 있다. 따라서 다른 생물군의 분리에 Ludox를 적용하기 위해서는 퇴적물 전처리 방법 및 대상생물이 존재하는 수층을 파악하는 사전실험이 반드시 필요하다.

• 환경생물
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• 제33권1호
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• pp.1-6
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• 2015

전세계적으로 2000년대 이후로 남조류에 의한 녹조의 발생이 증가하고 있으며, 이와 관련된 환경 문제가 공중건강을 위협하고 인간 활동을 제한하고 있다. 1970년대 캐나다의 호수를 중심으로 수행된 다년간의 현장 연구를 통하여, 녹조발생의 핵심적인 영양 제한인자로 인이 제시되었고, 인 저감에 대한 수계 관리가 진행되었다. 그러나 2000년대 이후, 대형 담수수계에서 특히 Microcystis에 의한 녹조 현상에서는 인뿐만 아니라 질소가 남조류 녹조 발생에 미치는 영향이 부각되고 있다. 한국의 담수 수계에서도 이와 비슷한 남조류에 의한 위해성 녹조 번성 특징을 갖고 있으므로, 이러한 패러다임의 변화는 국내 담수수계의 영양염류 관리에서 중요한 의미를 갖는다. 최근 국제적인 관련 연구를 통하여, 위해성 남조류 번성을 막기 위해 제안된 방법은 다음과 같다. 1) 질소와 인을 함께 관리하는 전략, 2) 폐수의 수집 및 처리, 3) 호소 유입수의 사전처리, 4) 저니의 준설, 5) 체류시간의 단축, 6) 조류의 효율적 회수법, 7) 조류의 침강 및 응집 등이 제시되고 있다. 추가적으로 남조류의 생태학적 특성에 기반한 지속가능하고 통합적인 담수수계의 녹조 관리기법이 수립되어야 한다. 녹조를 유발하는 남조류는 척결되어야 할 생물체가 아니라, 담수 수계에 필수적인 미생물 구성원이기 때문이다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.103-103
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• 2018

Oenothera biennis, commonly known as evening primrose, a potential source of natural bioactive substances: flavonoids, steroids, tannins, fatty acids and terpenoids responsible for a diverse range of pharmacological functions. However, whether extract prepared from aerial part of O. biennis (APOB) protects skin against oxidative stress remains unknown. To investigate the protective effects of APOB against oxidative stress-induced cellular damage and elucidated the underlying mechanisms in the HaCaT human skin keratinocytes. Our results revealed that treatment with APOB prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased viability, and the highest DPPH radical-scavenging activities and reducing power of HaCaT cells. APOB also effectively attenuated H2O2-induced comet tail formation and inhibited the $H_2O_2$-induced phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V-positive cells. In addition, APOB exhibited scavenging activity against intracellular reactive oxygen species (ROS) accumulation and restored the mitochondrial membrane potential loss by $H_2O_2$. Moreover, $H_2O_2$ enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase (PARP), a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with APOB. Furthermore, APOB increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2). According to our data, APOB is able to protect HaCaT cells from $H_2O_2$-induced DNA damage and cell death through blocking cellular damage related to oxidative stress through a mechanism that would affect ROS elimination and activating the Nri2/HO-1 signaling pathway.

• Fisheries and Aquatic Sciences
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• 제8권1호
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• pp.38-42
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• 2005

We evaluated the effects of different feeding strategies on the growth of young Nile tilapia, Oreochromis niloticus L., in a freshwater recirculating system during summer. Each of twenty fish (Mean body weight$\pm$ SD; 37. 7$\pm$0.10 g) were randomly distributed into each of 24 tanks. Eight treatments were prepared in triplicate. Control fish were hand-fed commercial feed twice daily without starvation. The other seven treatments employed different feeding and starvation strategies ranging from I day starved and 1 day fed (1DS+ 1DF) to 7 days starved to 7 days fed (7DS+7DF). All fish survived to the end of the 44-day feeding trial. The amount of food supplied was highest for the control fish in the control. Food supplied to fish in the 3DS+3DF and 4DS+4DF treatments was significantly lower than that of fish in the 1DS+1DF and 2DS+2DF treatments, but significantly higher than that of fish in the 5DS+5DF, 6DS+6DF and 7DS+7DF treatments. The weight gain of control fish was significantly higher than that of fish in other treatments. Feed efficiency ratio (FER) for fish in the 7DS+7DF treatment was significantly higher than that of fish in the control group, but it did not differ from that of fish in the 1DS+1DF and 2DS+2DF treatments. We concluded that young Nile tilapia raised with different starvation and feeding regimes during the summer in a freshwater recirculating system did not catch up in growth to fish fed daily. However, the enhanced FER of Nile tilapia in the 7DS+ 7DF, 2DS+ 2DF, and 1 DS+ I DF treatments partly explains the compensatory growth of the fish, although their weight gain was relatively low.

• Membrane and Water Treatment
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• 제15권1호
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• pp.21-29
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• 2024

1H,1H,2H,2H-perfluorodecytriethoxysilane (C₁₆H₁₉F₁₇O₃Si) be successfully applied to the hydrophobic modification of Al₂O₃ tubular ceramic membrane. Taking the concentration of modification solution, modification time, and modification temperature as factors, orthogonal experiments were designed to study the hydrophobicity of the composite membranes. The experiments showed that the modification time had the greatest impact on the experimental results, followed by the modification temperature, and the modification solution concentration had the smallest impact. Concentration of the modified solution 0.012 mol·L^-1, modification temperature 30 ℃ and modification time 24 h were considered optimal hydrophobic modification conditions. And the pure water flux reached 274.80 kg·m^-2·h^-1 at 0.1MPa before hydrophobic modification, whereas the modified membrane completely blocked liquid water permeation at pressures less than 0.1MPa. Air gap membrane distillation experiments were conducted for NaCl (2wt%) solution, and the maximum flux reached 4.20 kg·m^-2·h^-1, while the retention rate remained above 99.8%. Given the scarcity of freshwater resources in coastal areas, the article proposed a system for seawater desalination using air conditioning waste heat, and conducted preliminary research on its freshwater production performance using Aspen Plus. Finally, the proposed system achieved a freshwater production capacity of 0.61 kg·m^-2·h^-1.

• 해양환경안전학회지
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• 제21권6호
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• pp.617-636
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• 2015

목포항 주변은 인공 담수호(영산호, 영암호, 금호호)와 여러 육상기인 담수 유입원(소하천, 하수 처리장 방류수, 담지하수)이 분포되어 있다. 이 중 담수 유입량이 가장 많은 인공 호수의 방류 후 10일 이내에 목포항 주변해역에서 영양염(DIN, DIP, DSi)과 기타 수질인자(Chl-a, 수온, 염분, DO, COD, SS)의 분포 특성에 대해 2008년 1년 동안 4회(5월, 7월, 9월, 11월) 현장 조사를 수행하였다. 소하천, 하수처리장 방류수, 담지하수 등의 영양염 농도가 훨씬 더 높음에도 불구하고, 방조제 수문 개방을 통한 담수 방류가 주된 영향을 미치고 있었다. 통계 분석 결과 DIN, COD, 그리고 Chl-a가 염분과 음의 상관관계를 보였다. 따라서 영산호 방조제의 방류 규모와 시기, 그리고 영양염 농도는 전면 해역뿐만 아니라 외해역의 수질 분포에 있어서 중요 영향 인자임을 보이고 있다. 그러나 이번 조사 기간 중 9월에 영산호의 방류가 없었음에도, 하구역의 저층부에 영양염의 첨가가 발생하고 있었다. 이러한 결과는 영산강 하구역의 환경 및 생태계에 미치는 누적 영향에 대해 인공 담수호뿐만 아니라 다른 담수 유입원별 특징, 또는 저층 퇴적물로부터의 용출 등을 고려하여 통합적인 평가가 이루어져야 한다는 점을 나타내고 있다.

• 한국어병학회지
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• 제25권2호
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• pp.77-84
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• 2012

Various antibiotics, that could induce the appearance of resistant microorganisms, have been used for treatment or prevention of bacterial diseases in marine and ornamental fish. We determined and characterized the level of antibiotic-resistant bacteria and proportion of multi-drug resistant bacteria in intestinal microflora of both marine fish cultured in Korea and imported ornamental freshwater fish. For this the bacterial species and resistance to antibiotics were investigated in intestine of rock bream Oplegnathus fasciatus cultured in Korea and pearl gourami Trichogaster leeri imported from Singapore to characterise. Although the bacterial species were different, proportions of resistant bacteria to single antibiotics or multi-drug were higher in intestinal microflora of pearl gourami Trichogaster leeri imported from Singapore than in rock bream Oplegnathus fasciatus cultured in Korea. These results indicate that various antibiotics have been being used before trading without measures in the market of asian ornamental fishes, providing high risks for the emergence of multi-drug resistant bacteria.