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  • 1
    ISSN: 1432-1424
    Keywords: calcium current ; skeletal muscle ; sulfhydryl ; invertebrate muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Voltage-clamp experiments using the three-microelectrode voltage clamp technique were performed on ventroabdominal flexor muscles of the crustacean Atya lanipes. Potassium and chloride currents were found to underlie the normal, passive response of the muscle. Blocking potassium currents with tetraethylammonium and replacing chloride ions with methanesulfonate did not unmask an inward current. By treating the muscle with the sulfhydryl-alkylating agent 4-cyclopentene-1,3-dione an inward current was detected. The current induced by the agent is carried by Ca2+, since it is abolished in Ca2+-free solutions. The induced Ca+current is detected at about -40 mV and reaches a mean maximum value of -78 μA/cm2 at ca. -10 mV. At this potential the time to peak is close to 15 msec.The induced Ca2+ current inactivated with 1-sec prepulses which did not elicit detectable Ca2+ current; the fitted h xcurve had a midpoint of-38 mV and a steepness of 5.0 mV. Measurements of isometric tension were performed in small bundles of fibers, and the effects of the sulfhydryl-alkylating agents 4-cyclopentene-1,3-dione andN-ethylmaleimide were investigated. Tetanic tension was enhanced in a strictly Ca2+-dependent manner by 4-cyclopentene1,3-dione. The amplitude of K+ contractures increased after treatment with N-ethylmaleimide. It is concluded that Ca2+ channels are made functional by the sulfhydryl-specific reagents and that the increase in tension is probably mediated by an increase in Ca2+ influxthrough the chemically induced Ca2+ channels.
    Type of Medium: Electronic Resource
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  • 2
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    New York : Periodicals Archive Online (PAO)
    Foreign Affairs. 1:1 (1922/1923) 158 
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  • 3
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    New York : Periodicals Archive Online (PAO)
    Foreign Affairs. 6:1/4 (1927/1928) 41 
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  • 4
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    New York : Periodicals Archive Online (PAO)
    Foreign Affairs. 7:1/4 (1928/1929) 64 
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  • 5
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Medicine 44 (1993), S. 335-342 
    ISSN: 0066-4219
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ecology of freshwater fish 8 (1999), S. 0 
    ISSN: 1600-0633
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract– To assess the levels of gene introgression from cultured to wild brown trout populations, four officially stocked locations and four nonstocked locations were sampled for one to three consecutive years and compared to the hatchery strain used for stocking. Allozyme analysis for 25 loci included those previously described as providing allelic markers distinguishing hatchery stocks and native populations. Different levels of hybridization and introgression with hatchery índividuals were detected in stocked drainages as well as in protected locations. These findings indicate that new policies for stocking and monitoring hatchery fish are needed if gene pools of wild Spanish brown trout populations are to be preserved.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of fish biology 62 (2003), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The relations between allozyme heterozygosity, relative date of first feeding and life history strategy in juvenile Atlantic salmon Salmo salar were examined using eggs obtained from a 400 family cross (20 male × 20 female adult Atlantic salmon). Multilocus heterozygosity, through its positive associations with the timing of first feeding and growth rate, was correlated with life history strategy in juvenile Atlantic salmon, albeit under genotype × environmental (temperature, food availability) regulation. Under hatchery conditions, a 10 day difference was observed in the relative date of first feeding between early and late first feeding Atlantic salmon. Early first feeding Atlantic salmon exhibited a significantly higher mean heterozygosity, grew faster at ambient water temperature (April to November) and a significantly higher proportion adopted the early freshwater maturation (age 0+ years, male fish) or early migrant (age 1+ years, mainly female fish) strategies compared to late first feeding Atlantic salmon. Elevated water temperatures over the winter (December to April, 〉10·5° C) provided additional growth opportunity allowing previously mature male parr (mainly early first feeders) and lower modal group parr (mainly late first feeders) to adopt the early migrant strategy by the following spring.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 33 (1988), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The karyotypes of two samples of Salmo salar fry used to repopulate the rivers of Asturias (northern Spain) during 1986 were analysed: chromosomal polymorphism differed significantly between them. The need to repopulate with non-heterogeneous stocks is suggested.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Electrophoretic studies of proteins remain a primary source of insight into genetic diversity in many species including the Atlantic salmon Salmo salar, one of the most culturally and economically important fish species of the North Atlantic region. Since 1966, 〉350 scientific papers on protein variation have been published encompassing 25 000+ salmon from over 400 locations in 〉200 river systems across the species’ distribution. Variation has been detected at 30% of the 110 protein loci screened, though most studies examine 〈40. The method has been applied largely to the investigation of population structure and differentiation, but work has also led to the systematic revision of the genus Salmo and remains the primary source of insight into hybridization in the wild with brown trout Salmo trutta. Spatial patterns of differentiation show temporal stability, both within and among river systems, and strongly support structuring of the species into river and tributary specific populations and the designation of European and North American populations as distinct sub-species. They also show widespread regional differentiation within both continents, beyond the marked subcontinental differences between Baltic Sea and Atlantic Ocean populations in Europe. Most of the differentiation probably reflects gene flow and founder events associated with colonization following the retreat of the glaciers from much of the species’ modern range. However, variation at MEP-2* shows strong correlations with environmental temperature, both within and among rivers, and associations with phenotypic performance. This suggests selection is acting on the locus and provides compelling evidence for the local adaptation of populations. Protein studies have led to more population centred management of the species and have been exploited in the discrimination of regional stocks in mixed stock analysis in high seas fisheries, particularly in the Baltic Sea, and as markers for the assessment of stocking success. They have also advanced insight into how the genetic character of populations can be changed in cultivation and the potential impact of salmon aquaculture and stocking on wild populations. The method has been largely superseded by DNA based analyses, but the results remain highly relevant to Atlantic salmon management and conservation and are an irreplaceable data set for studying genetic stability of populations over time.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 67 (2005), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The extent of genetic variation and levels of temporal and spatial heterogeneity was investigated, at six polymorphic protein-coding loci, in wild Atlantic salmon Salmo salar populations from six rivers of Asturias (Northern Spain). Also, stocks from northern Europe that were among those introduced to repopulate Asturian Rivers, and other wild Spanish and European populations were characterized. The lack of temporal variation observed suggests that effective population sizes of Asturian populations are sufficiently large to prevent extreme levels of genetic drift and that the introduced fish had a negligible contribution to the fisheries of Asturian rivers.
    Type of Medium: Electronic Resource
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