CAJ | 학술논문

广东鲂（Megalobrama terminalis）是具重要经济价值的珠江流域特有鱼类，已列入国家级水产种质资源保护品种。近年来，随着河流固有生境持续破坏，重金属等水体污染问题不断加剧，以广东鲂为代表的当地特有鱼类资源急剧下降。文章以铜、镉暴露对广东鲂幼鱼48 h的半致死浓度值LC50暴露浓度强度为1个毒性单位（TU）为基准，以室内静水实验法研究了铜、镉离子在低效应浓度、中效应浓度、高效应浓度（分别对应于0.01 TU、0.03 TU和0.11 TU）胁迫对广东鲂幼鱼的氧化应激效应，以期找出适宜的生物标记物，完善珠江水域污染评价与预警体系。结果显示，广东鲂幼鱼MDA、GSH、T-AOC、SOD和CAT（以Pr计）随暴露浓度及暴露时间发生变化，其范围分别在1.08~7.34 nmol·mg-1、0.42~22.82 mg·g-1、0.10~1.32 U·mg-1、2.45~13.24 U·mg-1和0.01~0.09 U·mg-1之间。其中，GSH、MDA和T-AOC在铜、镉暴露后第1天迅速响应至高值，相应的各浓度处理组明显高于对照组。曲线回归结果显示，GSH与暴露浓度c（以TU量计）之间呈显著的二次曲线关系，拟合方程为GSH=-2112(c-0.084)2+18.1，r=0.847，n=10，P=0.012，暴露浓度阈值为0.084 TU。SOD和CAT则在暴露后第4天响应至高值。曲线回归结果显示， SOD 与 c 及 CAT 与 c 之间均呈显著的二次曲线关系，拟合方程分别为SOD=-2073(c-0.059)2+14.3，r=0.840，n=10，P=0.014；CAT=-21.2(c-0.056)2+0.102，r=0.877，n=10，P=0.006，相应的暴露浓度阈值分别为0.059 TU和0.056 TU。与暴露浓度呈显著的二次曲线关系的各指标中，GSH响应最为迅速，SOD和CAT的响应最为灵敏，加之SOD与CAT相关性极强，表明GSH、SOD和CAT这3种氧化应激指标可作为珠江流域水体污染的潜在生物标记物。
엄동방（Megalobrama terminalis）시구중요경제개치적주강류역특유어류，이렬입국가급수산충질자원보호품충。근년래，수착하류고유생경지속파배，중금속등수체오염문제불단가극，이엄동방위대표적당지특유어류자원급극하강。문장이동、력폭로대엄동방유어48 h적반치사농도치LC50폭로농도강도위1개독성단위（TU）위기준，이실내정수실험법연구료동、력리자재저효응농도、중효응농도、고효응농도（분별대응우0.01 TU、0.03 TU화0.11 TU）협박대엄동방유어적양화응격효응，이기조출괄의적생물표기물，완선주강수역오염평개여예경체계。결과현시，엄동방유어MDA、GSH、T-AOC、SOD화CAT（이Pr계）수폭로농도급폭로시간발생변화，기범위분별재1.08~7.34 nmol·mg-1、0.42~22.82 mg·g-1、0.10~1.32 U·mg-1、2.45~13.24 U·mg-1화0.01~0.09 U·mg-1지간。기중，GSH、MDA화T-AOC재동、력폭로후제1천신속향응지고치，상응적각농도처리조명현고우대조조。곡선회귀결과현시，GSH여폭로농도c（이TU량계）지간정현저적이차곡선관계，의합방정위GSH=-2112(c-0.084)2+18.1，r=0.847，n=10，P=0.012，폭로농도역치위0.084 TU。SOD화CAT칙재폭로후제4천향응지고치。곡선회귀결과현시， SOD 여 c 급 CAT 여 c 지간균정현저적이차곡선관계，의합방정분별위SOD=-2073(c-0.059)2+14.3，r=0.840，n=10，P=0.014；CAT=-21.2(c-0.056)2+0.102，r=0.877，n=10，P=0.006，상응적폭로농도역치분별위0.059 TU화0.056 TU。여폭로농도정현저적이차곡선관계적각지표중，GSH향응최위신속，SOD화CAT적향응최위령민，가지SOD여CAT상관성겁강，표명GSH、SOD화CAT저3충양화응격지표가작위주강류역수체오염적잠재생물표기물。
Guangdong bream (Megalobrama terminalis) is an endemic fish species with great economic value in the Pearl River watershed. It has been listed in the National Aquatic Germ-plasma Resources Conservation Project in China. However, as the natural habitats of the fishes is continuously destroyed, and heavy metals and other water pollution problems are aggravated, many endemic fish resources represented by Guangdong bream is sharply declined in recent years. In this study, a series static bioassay were carried out on Guangdong bream juvenile in order to find the appropriate biomarkers to improve the evaluation and early warning system for pollution in the Pearl River watershed. The fish were exposed to the separated or combined Cu2+ and Cd2+ at low, medium, and high toxic concentrations responding to 0.01 TU, 0.03 TU and 0.11 TU, respectively(1 TU, toxic unit is the 48 h LC50 of Cu2+ or Cd2+ in Guangdong bream juvenile) for 14 days. The substances and enzymes towards to oxidative stress including malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC) were determined on day 1, 4, 7, and 14 during the exposure period. The results show that MDA, GSH concentrations and T-AOC, SOD and CAT activities (all of the five substances were calculated by protein content, similarly hereinafter) in the juvenile bream were within the range of 1.08~7.34 nmol·mg-1, 0.42~22.82 mg·g-1, 0.10~1.32 U·mg-1, 2.45~13.24 U·mg-1and 0.01~0.09 U·mg-1, respectively, and varied according to exposure time and exposure concentrations.. The concentrations of GSH, MDA and the T-AOC activity in the fish were significantly increased after Cu2+ and Cd2+ exposure, and rapidly reached the peak on day 1. The relationship between GSH level and the exposure concentration (c, in the unit of TU) of Cu2+ and Cd2+ were well fitted with the conic curves GSH=-2112(c-0.084)2+18.1, r=0.847,n=10,P=0.012 on day 1, and the toxic concentration threshold was calculated as 0.084 TU. The other two substances SOD and CAT activities were also significantly elevated after Cu2+ and Cd2+ exposure and reached the peak on day 4. The relationships between SOD, CAT activities and the exposure toxic units of Cu2+ and Cd2+ were also well fitted with the conic curves SOD=-2073(c-0.059)2+14.3,r=0.840,n=10,P=0.014; CAT=-21.2(c-0.056)2+0.102,r=0.877,n=10,P=0.006, respectively on day 4, and the thresholds concentrations were 0.059 TU to SOD and 0.056 TU to CAT. In summary, GSH was the most rapid response substance to the exposure, while SOD and CAT activities were more sensitive to the exposure and more correlated to each other. This study suggests that GSH, SOD and CAT in the juvenileM. terminaliscould be developed as potential biomarkers for water pollution in the Pearl River watershed.