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  • 1
    Electronic Resource
    Electronic Resource
    Biochemical genetics of hybrid sunfish: Differential survival of heterozygotes (1974)
    Springer
    Biochemical genetics 11 (1974), S. 205-219 
    Details
    ISSN: 1573-4927
    Keywords: heterosis ; heterozygosity ; hybrids ; isozymes ; sunfish ; Centrarchidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Allelic segregation in reciprocal backcrosses involving the largemouth bass (Micropterus salmoides) and the F1 hybrid (largemouth bass × smallmouth bass, M. dolomieui) was investigated to determine the extent of euheterosis and luxuriance. The frequencies of allelic isozymes encoded in the lactate dehydrogenase E, malate dehydrogenase B, and isocitrate dehydrogenase loci were determined for reciprocal backcross progeny subjected to different selection pressures. The progeny of the backcross (male F1 × female largemouth bass) underwent a rapid loss of heterozygous individuals in a natural pond environment. When the offspring of this same mating were placed in artificial pools, where cannibalism is the main source of mortality, heterozygosity was advantageous. There was a marked correlation of increased heterozygosity at these enzyme loci with an increased growth rate. None of the above responses to selection was observed when the F1 hybrid served as the maternal parent in the reciprocal backcross. A maternal factor in the egg cytoplasm may influence the expression of heterosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486056
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  • 2
    Electronic Resource
    Electronic Resource
    Esterase polymorphism in the corn earworm, Heliothis zea (Boddie): A survey of temporal and spatial allelic variation in natural populations (1975)
    Springer
    Biochemical genetics 13 (1975), S. 885-898 
    Details
    ISSN: 1573-4927
    Keywords: Heliothis zea ; esterases ; isozymes ; allelic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Allelic variation at the Est-II locus was investigated in 22 natural populations of Heliothis zea from maize, separated spatially and temporally. Of the four alleles observed, Est-II b was the predominant one in every population. The relative frequency of Est-II b ranged from 0.57 to 0.85, with a mean of 0.72±0.06, and proved to be remarkably stable in space and time. Temporal changes in Est-II allele frequencies were observed at two of the sampling localities; however, principal component analysis and multiple correlation of genetic and environmental components have provided persuasive evidence that abiotic environmental or geographic variation is not related to differences in Est-II allele frequencies. Possible factors responsible for the maintenance of this polymorphism are discussed and include possible effects of the chemical composition of host plants and pesticides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484418
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  • 3
    Electronic Resource
    Electronic Resource
    Genetic and molecular analysis of nonrandom dimer assembly of the creatine kinase isozymes of fishes (1978)
    Springer
    Biochemical genetics 16 (1978), S. 811-829 
    Details
    ISSN: 1573-4927
    Keywords: isozymes ; creatine kinase ; fishes ; dimer ; restricted assembly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Species within many families of actinopterygian bony fishes (class Osteichthyes) have a two-banded allelic isozyme phenotype in individuals heterozygous at the creatine kinase A locus. This two-banded pattern is formed by the presence of the two homodimeric isozymes and the absence of the expected heterodimer. Sharks and amphibians have retained the ability to form all three allelic isozymes in individuals which are heterozygous. Reversible denaturation procedures were able to assemble the different allelic CK-A subunits within a species to form CK-A2 heterodimers. Furthermore, heterodimers were formed from different CK-A subunits from highly divergent species after this in vitro molecular hybridization process. It is concluded from these studies that the polypeptidebinding sites of creatine kinase are structurally conservative in most fishes and that the absence of a heterodimer in heterozygous individuals is not due to a structural incompatibility between the different A subunit types or to an instability of the heterodimer during electrophoresis. A temporal and/or spatial isolation of allelic CK-A subunit synthesis and assembly, within differentiated skeletal muscle, appears to have evolved in the actinopterygian bony fishes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484738
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Gas chromatographic/mass spectrometric identification of chlorinated and oxygenated cyclohexene artifacts formed during the analysis of chlorinated water samples (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 453-458 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chlorinated and oxygenated cyclohexene derivatives detected in methylene chloride extracts of chlorinated drinking water were demonstrated to be artifacts produced during sample preparation. Commercial methylene chloride contains cyclohexene as a preservative, and this reacted during the extraction/concentration process to produce microgram amounts of chlorocyclohexene, 2-chlorocyclohexanol, trans-1,2-dichlorocyclohexane, cyclohexenone and cyclohexenol. Quantitative analysis indicated that over 90% of the initial cyclohexene was consumed during the process. Dechlorination of drinking water with sodium arsenite significantly reduced but did not eliminate cyclohexene artifact formation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150807
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  • 5
    Electronic Resource
    Electronic Resource
    The gas chromatographic and mass spectrometric behavior of 2-amino-1-iodo-3-phenylpropane (iodoamphetamine) (1980)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 327-330 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas chromatographic and mass spectrometric behavior of 2-amino-1-iodo-3-phenylpropane (iodoamphetamine) was investigated. It was determined that the compound is unstable under the gas chromatographic mass spectrometric conditions used, undergoing a number of reactions and rearrangements. When iodoamphetamine hydrochloride was neutralized with base and the product examined by gas chromatography two peaks resulted. The major peak was identified as 2-benzylaziridine formed by the expulsion of HI from iodoamphetamine. The minor peak corresponded to iodoamphetamine itself. When an ethanolic solution of iodoamphetamine hydrochloride was injected into the gas chromatograph, however, three peaks were observed. Two of the three peaks had retention times identical to those identified previously. The other peak was concluded to be a chloro compound resulting from the opening of the aziridine ring with chloride ion.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200070803
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetic and thermodynamic considerations of the bracketing method: Entropy-driven proton-transfer reactions in a Fourier transform mass spectrometer (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 1602-1607 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several reports of experimentally derived proton affinity values and gas-phase basicity values for amino acids and peptides have recently appeared in the literature. Here, we show that the thermodynamic quantity that is measured by the Fourier transform mass spectrometry proton transfer bracketing of amino acids and peptides is gas-phase basicity and not proton affinity. Both experimental and theoretical evidence supports this conclusion. The difference between the values determined by proton transfer bracketing measurements for lysine versus leucine is consistent with a difference in gas-phase basicity rather than proton affinity. The rate of proton transfer from protonated lysine to a series of reference compounds have been measured. Entropy-driven, endothermic proton transfer is found to occur at the collision rate. Recent ab initio and semi-empirical calculations of the proton affinity of lysine are found to agree with the value that is derived from bracketing studies when one assumes that gas-phase basicity is measured. While entropy-driven reactions have been observed previously in high-pressure mass spectrometers, this is the first evidence for such reactions at low pressure in a Fourier transform mass spectrometer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210281236
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