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  • 1
    Electronic Resource
    Electronic Resource
    Total biodegradation of 4-chlorobiphenyl (4 CB) by a two-membered bacterial culture (1985)
    Springer
    Applied microbiology and biotechnology 21 (1985), S. 192-195 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Several bacterial strains that can oxidize mono- and dichlorinated biphenyls with one unsubstituted ring have already been described. The major route for this biodegradation leads ultimately to the corresponding chlorobenzoic acid, but several other minor chlorinated metabolites that might possibly be of concern for the environment have also been described previously. Since none of the bacterial strains that are able to oxidize these chlorinated biphenyls in pure culture are known to degrade chlorobenzoic acid, the oxidation of these substrates by axenic cultures always generates chlorobenzoates plus several other metabolites. In the present study, we have estimated the biodegradation of 4-chlorobiphenyl (4CB) by a two-membered bacterial culture containing one strain able to grow on 4CB and to transform it into 4-chlorobenzoate (4CBA) and one strain able to degrade 4CBA. The results were encouraging, since it was shown that the degradation of 4CB was more rapid and complete with the double bacterial culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295120
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  • 2
    Electronic Resource
    Electronic Resource
    Body condition and population regulation by food resources in moose (1984)
    Springer
    Oecologia 65 (1984), S. 44-50 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In southwestern Québec, non-harvested moose populations stabilize at a density of ≈0.40 animal·km-2. In an attempt to test population regulation by food resources, we investigated moose body condition near this equilibrium density (0.37) and at 2 lower densities (0.22 and 0.17). Annual population growth rates were evaluated at 4, 18, and 24% respectively. We predicted that moose in the high density area would exhibit growth retardation and poorer body condition, compared to moose in the lower density areas. Measurements of head length, cranial breadth, heart weight, and kidney weight were collected from 443 moose killed during the regular autumn harvesting seasons of 1981 and 1982. There was no indication that body condition was poorer at high moose density, and hence no evidence that foraging conditions were deteriorated. We concluded that food limitation was not sufficient to explain the differences in population growth rates. Predation by wolves and/or black bears is presented as an alternative and testable hypothesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384461
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  • 3
    Electronic Resource
    Electronic Resource
    Moose-wolf dynamics and the natural regulation of moose populations (1985)
    Springer
    Oecologia 65 (1985), S. 503-512 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In southwestern Québec, non-harvested moose populations stabilize at a density of ≃0.40 animal·km-2. In an attempt to test whether or not moose were regulated by predators, we investigated wolf predation near this equilibrium density (0.37) and at 2 lower densities (≃0.23, 0.17). Scat analysis in summer and feeding observations in winter indicated a greater use of alternative food resources by wolves at lower moose densities. Each wolf pack killed on average 5.3, 1.8, 1.1 moose·100 days in the area of 0.37, 0.23, and 0.17 moose·km-2, respectively. Consumption of moose per wolf was 2.8, 1.7, and 1.6 kg/day, respectively. January wolf densities were estimated at 1.38, 0.82, and 0.36 animals·100 km-2, respectively. Year-long predation rates proved to be density-dependent, increasing with moose density from 6.1 to 19.3% of the postnatal populations. We conclude that moose populations in southwestern Québec are regulated largely by predators (wolves and maybe black bears) at a density where competition for forage produces no detrimental effect. We support the concept that wolf predation can have an important regulatory effect at low moose densities but also a depensatory (inversely density-dependent) effect at higher densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379664
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  • 4
    Electronic Resource
    Electronic Resource
    Search or relax: the case of bachelor wood bison (1992)
    Springer
    Behavioral ecology and sociobiology 31 (1992), S. 192-203 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Males of gregarious species of mammals often do not associate with female groups during the breeding season. Such males could leave groups either to search for new breeding opportunities, or to restore body condition before rejoining new female groups. To investigate these two competing hypotheses, we studied the chronology of male wood bison (Bison bison athabascae) associating with females, and their aggressive and sexual behaviour over two breeding seasons. With increasing age, males were more often solitary, were more involved in aggressive interactions, investigated the genitals of females more frequently, and tended females more often. Group size did not affect whether or not males joined or left groups. The presence of oestrous females in a group did not affect the number of bulls in that group, and did not affect the joining or leaving of males. Older, dominant males did not exclude younger ones from female groups. Males observed outside female groups spent relatively more time feeding and resting than bulls in groups. Changes in group composition experienced by a male often involved the joining or splitting of female groups, as opposed to actual transfer of males between groups. Our results suggest that males leave female groups in order to recover, not for the purpose of searching for new female groups. We argue that due to the fluidity of wood bison groups, it is possible for a male to encounter new females even when remaining in a female group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00168647
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  • 5
    Electronic Resource
    Electronic Resource
    A paired-quadrat method for use in multiscale ordination (1994)
    Springer
    Plant ecology 113 (1994), S. 9-11 
    Details
    ISSN: 1573-5052
    Keywords: Multiscale ordination ; Paired quadrats ; Spatial pattern
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Multiscale ordination is a technique for examining spatial patterns of several species at several scales. We present a paired-quadrat method (paired quadrat covariance; PQC) to be used in multiscale ordination and test it with artificial data. Multiscale ordination with PQC successfully extracted the salient features of the data set. The method appears to be more sensitive than blocked-quadrat techniques for extracting small-scale patterns. We suggest that PQC will be useful as a complement to existing procedures or as a tool for analysing data from scattered quadrat arrangements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045459
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of new bacterial transformation products of 1,1,1-trichloro-2,2-bis-(4-chlorophenyl) ethane (DDT) by gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 741-752 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The microbial transformation of DDT, DDD and DDE was studied in Gram-negative strain B-206 and a number of phenolic metabolites were identified as the trimethylsilyl derivatives in the bacterial extracts by gas chromatography/mass spectrometry. The major metabolites of DDT were DDD, DDE, DDMU, 1,1,1-trichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′-chlorophenyl) ethane, 1,1,1-trichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′-hydroxy phenyl) ethane, and 1,1,1-trichloro-2,2-bis-(2-hydroxy-4-chlorophenyl) ethane. Conversely, DDD was mainly degraded into DDE, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′-cholorophenyl) ethane and 1,1-dichloro-2-(2-hydroxy-4-chloropheyl)-2-(4′-hydroxyphenyl) ethane. Finally, DDE was transformed into DDMU, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′-chlorophenyl) ethylene, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′hydroxyphenyl) ethylene and 1-chloro-2-(2-hydroxy-4-chlorophenyl)-2-(4′-chlorophenyl) ethylene. The phenolic metabolites exhibited [M - TMSCl]+., [M - HCl - TMSCl]+. and/or [M - HCl - TMSCl - Me]+ fragment ions which reflect the presence of an ortho hydroxyl group in these molecules. Other mass spectral features used to determine their struture are presented and a metabolic scheme accounting for their formation is proposed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180917
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    A comprehensive gas chromatographic/mass spectrometric analysis of 4-chlorobiphenyl bacterial degradation products (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 27-47 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bacterial metabolism of 4-chlorobiphenyl (4-CB), a model compound of polychlorinated biphenyls, has been investigated. Grown in the presence of 4-CB, Gram-negative strain B-206 oxidized the non-chlorinated ring to yield 2,3-dihydroxy-2,3-dihydro-4′-chlorobiphenyl, 3,4-dihydroxy-3,4-dihydro-4′-chlorobiphenyl, as well as their corresponding 2,3 and 3,4 catechol analogues, 2-hydroxy-4′-chlorobiphenyl and 4-hydroxy-4′-chlorobiphenyl. The intermediate catechols were further oxidized to yield 2-hydroxy-6-oxo-6-(4′-chlorophenyl)-hexa-2,4-dienoic acid, 2-hydroxy-6-oxo-(4′-chlorophenyl)-hexanoic acid, 5-oxo-5-(4′-chlorophenyl)-pentanoic acid, 4-oxo-4-(4′-chlorophenyl)-butanoic acid, 4-chlorocinnamic acid and 4-chlorobenzoic acid, which accumulates in the culture broths. The hydroxylated biotransformation products were characterized by gas chromatographic/mass spectrometric analysis as trimethylsilyl (TMS) and d9-TMS derivatives, whereas metabolites with vicinal diols were also analysed as their n-butylboronate derivatives. Gas chromatographic/mass spectrometric features of the metabolite derivatives are presented and 4-CB biodegradation pathways are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180106
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  • 8
    Electronic Resource
    Electronic Resource
    Intraspecific Variation in Home Range Overlap with Habitat Quality: A Comparison among Brown Bear Populations (2000)
    Springer
    Evolutionary ecology 14 (2000), S. 39-60 
    Details
    ISSN: 1573-8477
    Keywords: brown bear ; home range ; home range overlap ; seasonality ; space-use ; spatial organization ; territoriality ; Ursus arctos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We developed a conceptual model of spatial organization in vertebrates based upon changes in home range overlap with habitat quality. We tested the model using estimates of annual home ranges of adult females and densities for 30 populations of brown bears (Ursus arctos) in North America. We used seasonality as a surrogate of habitat quality, measured as the coefficient of variation among monthly actual evapotranspiration values for areas in which study populations were located. We calculated home range overlap for each population as the product of the average home range size for adult females and the estimated population density of adult females. Home range size varied positively with seasonality; however, home range overlap varied with seasonality in a nonlinear manner. Areas of low and high seasonality supported brown bears with considerable home range overlap, but areas of moderate seasonality supported brown bears with low home range overlap. These results are consistent with behavioural theory predicting a nonlinear relationship between food availability and territoriality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011019031766
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