title: Heavy metals induce oxidative stress and trigger oxidative stress-mediated heat shock protein (hsp) modulation in the intertidal copepod Tigriopus japonicus.
abstract: Heat shock proteins (hsps) are induced by a wide range of environmental stressors including heavy metals in aquatic organisms. However, the effect of heavy metals on zooplankton at the molecular level remains still unclear. In this study, we measured the intracellular reactive oxygen species (ROS) level and the antioxidant enzyme activities for 96 h after exposure to five heavy metals: arsenic (As), cadmium (Cd), copper (Cu), silver (Ag), and zinc (Zn) in the intertidal copepod Tigriopus japonicus. Activities of the antioxidant enzymes were highly elevated in metal-exposed copepods, indicating that heavy metals can induce oxidative stress by generating ROS, and stimulate the involvement of antioxidant enzymes as cellular defense mechanisms. Subsequently, transcriptional changes in hsp gene families were further investigated in the metal-exposed groups for 96 h. The ROS level and glutathione (GSH) content were significantly increased in Ag-, As-, and Cu-exposed copepods, while they were only slightly elevated in Cd- and Zn-exposed groups. Based on the numbers of significantly modulated hsp genes and their expression levels for 96 h, we measured the effect of heavy metals to stress genes of T. japonicus in the following order: Cu > Zn > Ag > As > Cd, implying that Cu acts as a stronger oxidative stress inducer than other heavy metals. Of them, the expression of hsp20 and hsp70 genes was substantially modulated by exposure to heavy metals, indicating that these genes would provide a sensitive molecular biomarker for aquatic monitoring of heavy metal pollution.
authors: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea.
authors: Bo-Mi
authors: BM
authors: Kim
authors: Department of Marine Science, College of Natural Sciences, Incheon National University, Incheon 406-772, South Korea.
authors: Jae-Sung
authors: JS
authors: Rhee
authors: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors: Chang-Bum
authors: CB
authors: Jeong
authors: Pathology Team, National Fisheries Research & Development Institute, Busan 619-902, South Korea.
authors: Jung Soo
authors: JS
authors: Seo
authors: Department of Marine Biotechnology, College of Liberal Arts and Sciences, Anyang University, Ganghwa 417-833, South Korea.
authors: Gyung Soo
authors: GS
authors: Park
authors: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 110-743, South Korea. Electronic address: ymlee70@smu.ac.kr.
authors: Young-Mi
authors: YM
authors: Lee
authors: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea. Electronic address: jslee2@skku.edu.
authors: Jae-Seong
authors: JS
authors: Lee
mesh_terms: D000818:Animals; D017756:Aquaculture; D060829:Arthropod Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D033342:Copepoda / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D005978:Glutathione / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D050886:HSP20 Heat-Shock Proteins / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D008297:Male; D019216:Metals, Heavy / Q000008:administration & dosage / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000819:agonists / Q000378:metabolism; D056910:Republic of Korea; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D060829:Arthropod Proteins; D015415:Biomarkers; D050886:HSP20 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D019216:Metals, Heavy; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D010088:Oxidoreductases; D005978:Glutathione
keywords: Antioxidant enzyme activities; Copepod; Heat shock protein; Heavy metal; Oxidative stress; Tigriopus japonicus