Physiological and biochemical responses of Ulva pertusa to metal exposure

Geonhee Kim(김건희),Jihae Park(박지혜),Soyeon Choi(최소연),Hojun Lee(이호준),Taejun Han(한태준) 환경독성보건학회 2021 한국독성학회 심포지움 및 학술발표회 Vol.2021 No.5

The green alga Ulva is considered to be a simple, homogeneous algal form with little functional differentiation within the thallus. Functional differentiation of the thallus is a strategy that contributes to the survival of Ulva pertusa as an opportunistic alga. Although many ecotoxicity assessments have been conducted based on spore-forming properties of the marginal thallus parts, ecotoxicity using the middle parts of the thallus has rarely been achieved. Therefore, we investigated the response of the middle and marginal thallus region of Ulva pertusa to exposure of six heavy metals (Cu, Cr, Cd, Ni, As, Ag). Concentration-dependent reduction in disc size, Fv/Fm, ETRmax and pigment were observed with Ag being the most toxic to Ulva pertusa.

Toxic effects of Volatile Organic Compounds (VOCs) on motility and photosynthesis using freshwater algae, Euglena agilis Carter

Hoon Choi(최훈),Sreejith Kottuparambil(스리짓),Youn-Jung Kim(김연정),Taejun Han(한태준) 환경독성보건학회 2014 한국독성학회 심포지움 및 학술발표회 Vol.2014 No.5

Development of photosynthesis biosensor for drinking water quality monitoring

Soyeon Choi(최소연),Jihae Park(박지혜),Hojun Lee(이호준),Geonhee Kim(김건희),Taejun Han(한태준) 환경독성보건학회 2021 한국독성학회 심포지움 및 학술발표회 Vol.2021 No.5

The unprecedented increase in anthropogenic pollution of the aquatic environment has made the development of sensitive, cost-effective and adaptable early warning systems for monitoring chemical pollutants absolutely crucial. Biosensors based on aquatic plants could provide a cost-effective alternative for environmental risk analysis, as they can provide rapid information on toxicity in case of pollution, while assessing the hazardous effects of pollutants on the aquatic ecosystem. In this work, an optical biosensor based on chlorophyll-a fluorescence was developed to monitor aquatic pollutants specifically for drinking water quality. The response of the biosensor was investigated using Spirodela polyrhiza, also known as duckweed, as a test species over a1-h acute exposure to atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), which is the most widely used herbicide worldwide to control hardwood and grass weeds. The detection concentration was 0.6 mg/L, which was calculated using a specific equation based on the acceptable daily intake (ADI; μg/kg/day) of the WHO drinking water guideline, standard weight (kg) and daily drinking water intake (L/day). Chl-a fluorescence of S. polyrhiza at the detection concentration of 0.6 mg/L decreased by more than 20% compared to the control.

Ulva bioassay as a tool to assess potential toxicity in industrial wastewater

Hojun Lee(이호준),Kisik Shin(신기식),Jihae Park(박지혜),Soyeon Choi(최소연),Geonhee Kim(김건희),Stephen Depuydt(스테픈 데퓨잇),Taejun Han(한태준) 환경독성보건학회 2021 한국독성학회 심포지움 및 학술발표회 Vol.2021 No.5

Industrial wastewater is a complex source of organic and man-made pollutants containing numerous metal ions. These effluents can be a major problem for the environment due to their complex chemical content, which is known for its toxicity and low biodegradability, which can have harmful effects on the aquatic environment. In this study, we used the green macroalga Ulva pertusa to evaluate the toxicity of wastewater samples from 99 industries in South Korea and to characterize the relationship between ecotoxicity and chemical content to identify chemicals that could contribute to overall ecotoxicity. Although the metal content of most of the effluents did not exceed the allowable criteria, the measured ecological toxicity of the effluents is related to Cd, Cu, Ni, Pb and Zn. Specifically in the area of metals, the Ulva bioassay shows a positive and important relationship with Cr. These results highlight the importance of biological assays to continuously monitor the toxicity of treated wastewater to prevent harmful effects on the environment. The results also suggest that ecotoxicity data are needed in parallel with chemical data to better assess the safety of wastewater discharges to the environment.

Comparison of domestic inter-laboratory test results for aquatic toxicity bioassessment method based on sporulation inhibition in Ulva pertusa Kjellman (Chlorophyceae)

Mi-seong Kim(김미성),Hoon Choi(최훈),Sreejith Kottuparambil,Youn-Jung Kim(김연정),Taejun Han(한태준) 환경독성보건학회 2014 한국독성학회 심포지움 및 학술발표회 Vol.2014 No.5

Toxicity testing of wastewater and inter-laboratory comparison based on Lemna minor root elongation

Jihae Park(박지혜),Eun-Jin Yoo(유은진),Kisik Shin(신기식),Soyeon Choi(최소연),Hojun Lee(이호준),Geonhee Kim(김건희),Stephen Depuydt(스테픈 데퓨잇),Jonas De Sager(요나스 데 세거),Taejun Han(한태준) 환경독성보건학회 2021 한국독성학회 심포지움 및 학술발표회 Vol.2021 No.5

The Lemna minor root regrowth test method is a toxicity test performed with very simple equipment and only one L. minor plant (two- to three-frond) in each culture well, cutting the roots before exposure and measuring the regrowth of the newly developed roots after three days. As a substrate for laboratory toxicity assays, L. minor has the advantages of small size, structural simplicity and rapid growth. Compared to the three internationally standardized methods, this bioassay is faster, simpler, more convenient and cheaper. It can be applied to a variety of sample types, including (a) individual chemicals, commercial products or known mixtures of chemicals, (b) industrial or urban freshwater effluents, elutriates or leachates and (c) surface freshwater or receiving waters. The test can be used alone or as part of a test battery to determine and monitor the toxic effects of individual substances or complex mixtures that may be harmful to aquatic life in freshwater ecosystems, and as a weight-of-evidence approach to determine the need for controlling discharges and setting effluent standards.

중파자외선에 대한 남극산 해조류의 광합성 및 자외선 흡수물질 형성 반응

한태준,박병직,한영석,강성호,이상훈 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.3

남극에 생육하는 5종의 홍조류(Curdiea racovitzae, Gigartina skottsbergii, Mazzaella obovata, Myriogram- me manginii, Palmaria decipiens)를 대상으로 인공 중파 자외선과 태양광선에 대한 종별 생리적 반응을 광합성이라는 파라미터를 사용하여 조사 연구하였다. 실험실 연구 결과,종간에 중파 자외선에 대한 내성 차이가 확인되었으며 이러한 차이는 각 종들이 채집되기 전에 서식하고 있었던 수심과 매우 밀접한 관계가 있어서 20~30m의 수심에서 채집된 M. manginii와 P. decipi-ens의 자외선 내성이 다른 종들에 비하여 작게 나왔다. 본 연구 결과는 서식지 주변의 광환경이 해조류의 자외선 내성을 결정해 주는 한 요인이라는 가설을 입증해주었을 뿐 아니라 형광 변화를 이용한 광합성 측정법은 자외선 내성을 타진하는데 있어서 매우 신속하고 비파괴적인 방법으로 이용될 수 있음을 입증하였다. 두 종의 홍조류(M. manginii, P. decipiens)를 대상으로 태양광선 하에서의 광합성 효율을 관찰한 결과, 정오 에 최저 광합성을 보인 반면 저녁에는 광합성 능력이 회복되는 현상을 나타내었다. 이같은 동적인 광저해 현 상(dynamic photoinhibition)은 일종의 광적응 능력으로서 식물이 비교적 강한 태양광선에 노출된 지역에 성공적으로 서식하는데 크게 기여하는 것으로 사료된다. 본 연구에서는 또한 태양광선내 중파자외선 포함 유무에 따라 광합성 회복 속도에 차이가 나는 것을 볼 수 있었는데 중파자외선이 포함된 태양 광선 하에서는 광합성의 회복이 느린 반면,중파 자외선이 제거된 조건에서는 광합성이 비교적 빨리 회복되는 것을 관찰할 수 있었고 이는 중파 자외선이 광합성 회복 기작을 지연시키는 작용을 한 것으로 해석될 수 있다. 야외에서 자외선 민감성을 비교한 결과, P decipiens가 M. manginii에 비하여 자외선 내성이 큰 것으로 나타났는데,두 종 공히 조간대로부터 조하매 상부까지 서식하는 종임에도 불구하고 이러한 내성차이를 보인 이유는 자외선 흡수물질의 정량적인 차이에 기인한다고 할 수 있다. M. manginii와 P. decipiens에서 발견된 자외선 흡수물질의 양은 약 1.2 정도의 비율을 보였는데 이러한 정량적 차이가 자외선 민감성에 기여한 것으로 사료된다. 본 연구에서는 또한 계절별 그리고 채집 수심별로 자외선 흡수물질의 정량적 차이를 발견할 수 있었는데 태양광선이 풍부한 여름철에 그리고 고광량이 도달되는 수심 얕은 곳에 서식하는 개체가 더욱 많은 양의 자외선 흡수물질을 함유한 것으로 나타났다. Effects of artificial and solar UV-B radiation on five rhodophytes (Curdiea racovitzae, Gigartina skottsbergii, Mazzaella obovata, Myriogramme manginii, Palmaria decipiens) from Antarctica have been investigated using PAM fluorescence in laboratory and in the field. Laboratory studies showed that there were significant differences in the UV sensitivity between different species, and that the differences appeared to be correlated with the depth of collection of the specimens. It was apparent from the observations that the samples such as M. manginii and P. decipiens collected from 20∼30 m depths were more sensitive to UV-B radiation compared with those collected from shallower depths. The present study confirmed that an acclimation to the surrounding light regime could be an important factor to determine the UV-sensitivity of a species or individuals and that PAM measurements are rapid and non-destructive methods to evaluate UV influences. From field studies on M. manginii and P. decipiens it was observed that both plants exhibited changes in the effective quantum yield, with the minimum values at noon followed by a recovery in the evening. Photoinhibition occurred in these species could therefore be accounted for by so-called dynamic photoinhibition. It seems likely that this protective mechanism may contribute to survival of the species in shallow water where they may encounter intense solar radiation. The presence or absence of the UV-B component under solar radiation differently affected the photosynthetic recovery process, and the rate of recovery was much slower in UV-present than in UV-absent conditions. Functional role of UV-B appears to delay the recovery of photosynthesis in the studied macroalgae. Differential sensitivity to UV-B recognised between M. manginii and P. decipiens seemed to correspond well with the amount of UV-absorbing substances(UVAS) contained in the respective species. Higher tolerance to solar radiation by the latter species may be due to the higher amount of UVAS. There were variations of UVAS concentrations in algal thalli depending on the season and depth of collection.

자외선이 해조류에 미치는 영향에 관한 고찰

한태준 한국환경생물학회 1999 환경생물 : 환경생물학회지 Vol.17 No.1

산업활동의 부산물인 chlorofluorocarbons(CFCs)와 같은 물질들의 대기권 유입으로 오존층의 파괴가 극심해짐에 따라 자외선의 지표유입량이 증가되는 추세를 보이는데, 특히 중파자외선의 증가는 DNA, 단백질, 지질 등에 의한 흡수를 통하여 생물학적 폐해를 야기할 수 있다는 점에서 주목된다. 최근 측정 결과 우리 나라 동해안에서 해수표면에 도달되는 중파자외선 광량의 1%가 수심 10m까지 침투하는 것으로 나타났는데, 이는 해양생태계 생산성의 대부분이 해양 수심의 상위 2.5%에 해당되는 투광대에 의존한다는 점을 감안할 때 자외선에 의한 막대한 생태학적 폐해를 예견하게 해준다. 실내배양실험 연구에서 중파자외선은 대형해조류의 생장 및 광합성을 억제하고 광합성 색소를 파괴하는 등의 생물독성학적 효과를 보였다. 반면, 자외선의 피해로부터 해조류를 보호해 주는 몇 가지 기작이 밝혀진 바 있는데, 어린시기의 갈조류 다시마는 청색광에 의한 광재활성화 능력을 함유한 것으로 보이고, 한국산 녹조 구멍갈파래와 홍조 도박류에서는 자외선을 강하게 차단하는 흡수물질이 형성됨을 알 수 있었다. 그러나 이러한 적응기능들이 해조류에서 보편적으로 나타나는 것인지에 대해서는 좀 더 연구가 필요하다. 해양생태계는 대기 중 CO_2를 이용하여 1년에 약 100Gt의 유기물질을 생산해내고, 인류가 소비하는 식품의 30%를 제공한다는 점에서 자외선에 의한 생물량의 감소는 해조류 뿐만 아니라 먹이망에 의해서 복잡한 연결구조를 지닌 생태계 전체의 붕괴를 야기할 수 있는 심각한 사안이라고 할 수 있다. 따라서, 자외선에 대한 피해를 연구 평가하여 전략을 세우고 이를 예측하는 예보시스템을 개발할 필요성이 절실히 부각된다. Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B(280∼320㎚) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level(2.0 Wm^-2) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV damage have been found, which include photoreativation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half or the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large-scale deterioratlion in aquatic ecosystem.