摘要:

Metallothionein, a low-molecular-weight protein whose apoprotein, thionein, is induced by exposure to cadmium, copper, mercury, and zinc, plays an important role in the transport and storage of heavy metals; it also provides a protective role against the toxic effects of these metals by sequestering and thus reducing the amount of the free metal ions. Interest in the detoxification role of metallothionein in fisheries research and aquatic toxicology has increased because of the increasing contamination of aquatic habitats by heavy metals. Reports of laboratory and field investigations have shown that metallothionein synthesis is induced in fishes during chronic and acute exposures to metals. There is also evidence of the presence in fish of low-molecular-weight inorganic-binding proteins that are different from metallothionein, as well as evidence that cadmium is not sequestered by metallothionein in rainbow trout Salmo gairdneri. The sequestering of metal contaminants by metallothionein and subsequent toxic effects in fish and other animals has been described by the “spillover” hypothesis, which states that once metallothionein is saturated by metals, excess metal ions spill over into other cellular compartments and cause pathological lesions. We review the literature on metallothionein in fish, and emphasize the protein's role in the detoxification and binding of metal contaminants.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<596:MIF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The influences of exposure to aluminum and increased acidity on mortality, growth, behavior, and biochemical responses of brook trout Salvelinus fontinalis were evaluated as a function of developmental stage. Eyed eggs and young brook trout were exposed until 30 d after hatching in proportional diluters to pHs of 4.5, 5.5, and 7.2, with and without aluminum (300 μg/L); 37-d-old brook trout that had been held in experimental control water since hatching were exposed to these same conditions for 30 d. Exposure conditions (i.e., aluminum and calcium concentrations and pH) simulated conditions in some headwater lakes and streams in the northeastern United States. Adverse effects on exposed brook trout generally increased as pH decreased from 7.2 to 4.5 and potentiation of effects by aluminum occurred at pHs of 5.5 to 7.2. However, embryos and fish older than 36 d were more tolerant of acidic conditions and aluminum than were larvae less than 15 d old. We conclude that the adverse effects on mortality, growth, behavior, and biochemical responses of brook trout at pH 4.5 with or without 300 μg/L aluminum, and at pH 5.5 with 300 μg/L aluminum, would make survival improbable under similar conditions in nature.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<610:ITOAAA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A fluorometric procedure has been designed to quantify the uptake and release of submicrogram quantities of the antibiotic oxytetracycline (OTC) by young sockeye salmon Oncorhynchus nerka. Juveniles and smolts were homogenized in 5% trichloroacetic acid, the solute containing OTC was extracted with ethylacetate, and the OTC within the ethylacetate phase was shaken with calcium to form a fluorescent complex. Fluorescence intensity was linearly related to OTC concentration for both OTC standard solutions and samples extracted from fish. Efficiencies of OTC extraction averaged 36% for standard solutions and 32% for spiked biological material and were independent of OTC concentration for sample spikes ranging from 0.47 to 9.4 μg OTC; the minimum quantity that could be detected against background was 0.17 μg OTC. The method allowed OTC to be detected in 100% of test fish when they were 33 mm long (0.4 g) after 29 d feeding on treated food; usual standard methods allowed 100% detection only after 54 d of treatment, when fish were 44 mm long (0.8 g). Oxytetracycline, which chelates to calcium, was taken up both by bone, where calcium turnover is slow, and by skin, scales, and other sites of rapid calcium turnover. The amounts of OTC in the latter tissues declined once treatment was stopped, but OTC quantities remained stable in bone. The longer OTC-impregnated feeds were given, the more OTC was taken up by bone, which allowed sublots of fish to be uniquely tagged. We were able to distinguish two differentially marked groups of fish 9 months after treatment stopped, by which time the fish had overwintered and become smolts. The smallest fish that secreted reliably detectable OTC into bone were 40 mm long (0.6 g).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<621:QDOOUA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

When 0.2-g pink salmon Oncorhynchus gorbuscha were carried by helicopter in Alaska, total gas pressure in the transport water reached 71.3 mm Hg (109.4% of barometric pressure). Gross and microscopic lesions in swim bladders of fish progressed during transport to tympanitic dilatation, then to separation of laminae and rupture. Other associated signs and lesions were exophthalmos, cranial swelling, edematous gill lamellae, hemoperitoneum, emphysema of the yolk sac, and distension and rupture of the yolk sac membrane. Rapid reduction of barometric pressure during the flight and the subsequent increase in dissolved-gas supersaturation caused gas bubble disease and tissue alterations that affected health and survival of the fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<630:GBDDTH>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

We examined the possibility that parasites affect survival rates of anadromous hatchery coho salmon Oncorhynchus kisutch during their period in the wild. Survival was estimated from the rates at which adults returned to the hatchery. The frequency of infection of heart tissue by metacercariae of Nanophyetus sp. was higher in individuals from families with relatively high survival. Various degrees of parasitic and bacterial infection were observed in all groups. We frequently saw extensive infection and tissue reaction to trophozoites of Ceratomyxa sp. (probably C. shasta) in the apparent absence of spores, suggesting that the clinical method now used to determine the presence of Ceratomyxa infection needs to be reassessed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<636:PBIEFO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Fish Immunology.Edited by M. J. Manning and M. F. Tatner. Academic Press, London. 1985. 374 pages. $32.50. Reviewed by B. R. Griffin,Fish Farming Experimental Station, U.S. Fish and Wildlife Service, Stuttgart, Arkansas 72160, USA.

ISSN:0002-8487    

DOI:10.1577/00028487.1985.10492818

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor