title: Zinc bioaccumulation and ionoregulatory impacts in Fundulus heteroclitus exposed to sublethal waterborne zinc at different salinities.
abstract: Exposure of Fundulus heteroclitus to an environmentally relevant Zn concentration (500 μg L⁻¹) at different salinities (0, 3.5, 10.5, and 35 ppt) revealed the following effects: (i) plasma [Zn] doubled after exposure at 0 ppt, a response which was eliminated at 35 ppt. Tissue [Zn] also increased in gill, liver, intestine, and carcass at 0 ppt. (ii) Both branchial and intestinal Ca2⁺ ATPase activities decreased in response to Zn at 0 ppt and were elevated at 35 ppt. Plasma [Ca] decreased by 50% at 0 ppt and by 30% at 3.5 ppt and increased by 20% at 35 ppt. Gill [Ca] decreased by 35% at 0 ppt and increased by about 30% at all higher salinities. (iii) Branchial Na⁺,K⁺ ATPase activity decreased by 50% at 0 ppt, increased by 30% and 90% at 10.5 and 35 ppt respectively. Intestinal Na⁺,K⁺ ATPase activity was reduced by 30% at 0 ppt. (iv) Plasma [Na] decreased by 30% at 0 ppt in Zn-exposed. Zn exposure also disturbed the homeostasis of tissue cations (Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺) in a tissue-specific and salinity-dependent manner. (v) Drinking rate was not altered by Zn exposure. In toxicity tests, acute Zn lethality (96-h LC50) increased in a close to linear fashion from 9.8 mg L⁻¹ at 0 ppt to 75.0 mg L⁻¹ at 35 ppt. We conclude that sublethal Zn exposure causes pathological changes in both Ca⁺⁺ and Na⁺ homeostases, and that increasing salinity exerts protective effects against both sublethal and lethal Zn toxicities.
authors: Departamento de Química, Universidade Federal de Santa Maria (UFSM), Av. Roraima 1000, Santa Maria, RS, Brazil 97105-900. Electronic address: vania.loro@gmail.com.
authors: Vania Lucia
authors: VL
authors: Loro
authors: Universidade Federal do Rio Grande (FURG), Instituto de Ciências Biológicas, Rio Grande, RS, Brazil 96201-900.
authors: Lygia
authors: L
authors: Nogueira
authors: Dept. of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.
authors: Sunita R
authors: SR
authors: Nadella
authors: Dept. of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.
authors: Chris M
authors: CM
authors: Wood
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001267:Atlantic Ocean; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005393:Fish Diseases / Q000097:blood / Q000139:chemically induced* / Q000378:metabolism / Q000517:prevention & control; D029941:Fish Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D023781:Fundulidae; D005880:Gills / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D059165:Hormesis; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000737:chemistry / Q000187:drug effects*; D007928:Lethal Dose 50; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009513:New Hampshire; D054712:Salinity; D014018:Tissue Distribution; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D014883:Water-Electrolyte Imbalance / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control / Q000662:veterinary*; D015032:Zinc / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D029941:Fish Proteins; D014874:Water Pollutants, Chemical; D000251:Adenosine Triphosphatases; D015032:Zinc
keywords: Ca(2+) ATPase; Calcium homeostasis; Killifish; Na(+),K(+) ATPase; Salinity; Sodium homeostasis; Zinc