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  • 1
    Electronic Resource
    Electronic Resource
    Metabolism of tannin-protein complex by facultatively anaerobic bacteria isolated from koala feces (1993)
    Springer
    Biodegradation 4 (1993), S. 91-99 
    Details
    ISSN: 1572-9729
    Keywords: tannin-protein complex ; gallate ; pyrogallol ; phloroglucinol ; koala
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The metabolic pathways involved in degradation of tannin-protein complex (T-PC) were investigated in various facultatively anaerobic bacteria, with specific reference to fecal isolates from the koala including T-PC-degrading enterobacteria (T-PCDE),Streptococcus bovis, Klebsiella pneumoniae, andK. oxytoca. It was demonstrated that T-PCDE andS. bovis biotype I were capable of degrading protein complexed with gallotannin (a hydrolyzable tannin), but not that complexed with quebracho (a condensed tannin). Subsequent studies showed that these strains metabolized gallic acid to pyrogallol. Strains ofKlebsiella pneumoniae andK. oxytoca, which did not degrade T-PC, also metabolized gallic acid into pyrogallol. Pyrogallol was not degraded by any strains studied, but it was not detected in fresh feces of the koalas. The majority of strains isolated from feces could degrade phloroglucinol. Based on these findings, we propose that members of the gut microflora of the koala cooperate in the degradation of T-PC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702325
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  • 2
    Electronic Resource
    Electronic Resource
    Methods and pitfalls of extracting condensed tannins and other phenolics from plants: Insights from investigations onEucalyptus leaves (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 123-134 
    Details
    ISSN: 1573-1561
    Keywords: Tannin extraction ; plant phenolics ; Eucalyptus ; browse analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Optimal conditions for extraction of tannins and other phenolics from tree foliage and their subsequent storage rarely have been investigated. We investigated methods of drying leaves, optimal solvents, and the effects of light and temperature on the extractability and stability of condensed tannins (proanthocyanidins) and total phenolics from leaves ofEucalyptus trees. Aqueous acetone was a better solvent than aqueous methanol for condensed tannins and total phenolics, but condensed tannins were less stable in aqueous acetone than aqueous methanol. Stability of condensed tannins also was decreased substantially by room temperature versus 4°C and by exposure to indirect sunlight, although the assay for total phenolics was unaffected. For quantitative estimation of condensed tannins, extraction with 50% acetone was better than methods of direct analysis of leaf tissue. The highest estimates of total condensed tannins were obtained by exhaustive extraction with 50% acetone followed by direct analysis of the residue. Lyophilization of fresh leaf increased yield of condensed tannin (although usually by less than 10%). Lyophilization and subsequent storage of extracts had little effect on assays for condensed tannins or total phenolics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994426
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  • 3
    Electronic Resource
    Electronic Resource
    Consequences of biotransformation of plant secondary metabolites on acid-base metabolism in mammals—A final common pathway? (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 721-743 
    Details
    ISSN: 1573-1561
    Keywords: Plant secondary metabolites ; biotransformation ; detoxification ; herbivore ; marsupial ; lagomorph ; acidosis ; ammonium ; phosphorus ; sodium ; organic acids ; kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Regulation of acid-base homeostasis is essential for mammals and birds. Biotransformation and metabolism of absorbed plant secondary metabolites (PSMs) results in the production of organic acids that threaten acid-base homeostasis. Consequently these acids must be buffered and excreted from the body. The production of an acid load from detoxified PSMs should occur in herbivorous mammals and birds and with most PSMs and so may provide a unifying theme to explain many effects of PSMs on animal metabolism. Since the organic acids will be largely ionized at physiological pH, disposal of the hydrogen ion and the organic anion may proceed independently. Most hydrogen ions (H+) from organic acids are eliminated by one or more of three ways: (1) when they react with bicarbonate in the extracellular fluid to form carbon dioxide and the carbon dioxide is exhaled, (2) when they bind to dibasic phosphate and are excreted by the kidney as monobasic phosphate, and (3) when they are buffered and retained in the skeletal system. The secretion of phosphate ions and ammonium excretion are two ways in which the kidney replaces bicarbonate ions that have been eliminated as carbon dioxide. Secretion in the kidney tubule is an important means of excreting excessive organic anions rapidly. This process is saturable and may be subject to competition from a variety of different metabolites. Lagomorphs have limited capacity to form new bicarbonate from ammonium excretion and may therefore be obliged to excrete other cations such as sodium to balance the excretion of organic anions from PSMs. Acidemia has wide-ranging impacts on animals but browsing mammals and birds may have to break down muscle tissues to provide for urinary ammonium in order to generate bicarbonate for buffering. Acidemia also can affect the extent of urea recycling. Animals consuming browse diets may have to regulate feeding so that the rate of formation of hydrogen ions does not exceed the rate of disposal. The mechanisms by which this could occur are unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033457
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  • 4
    Electronic Resource
    Electronic Resource
    Diversity and habitat relationships of hypogeous fungi. II. Factors influencing the occurrence and number of taxa (2000)
    Springer
    Biodiversity and conservation 9 (2000), S. 175-199 
    Details
    ISSN: 1572-9710
    Keywords: Australia ; forests ; fungi ; hypogeous ; statistical models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fruit-bodies of hypogeous fungi were sampled over two seasons across 136 forested study sites representing a stratified sample of the climatic, geological and topographic features of far south-eastern mainland Australia. Two hundred and nine species, over three-quarters being undescribed, were recorded. Statistical models based on various environmental attributes measured for each site were developed for the occurrence of several common taxa. At a landscape scale, climatic factors such as mean minimum temperature of the coldest month and annual mean moisture index were important explanatory variables for most taxa examined, but the type of response varied. More locally, topographic position, soil fertility, time since last fire and micro-habitat structures such as the leaf litter layer and number of large fallen trees also influenced the distribution of taxa in different ways. A model was then developed for the number of fungal species occurring at each site. Important explanatory variables were type of substrate, topography and diversity of potential host eucalypt species. The utility of each model constructed needs evaluation by further sampling of hypogeous fungi. Possible implications of our findings for forest management are discussed. Further analyses of our existing data are also identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008962711138
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Diversity and habitat relationships of hypogeous fungi. I. Study design, sampling techniques and general survey results (2000)
    Springer
    Biodiversity and conservation 9 (2000), S. 151-173 
    Details
    ISSN: 1572-9710
    Keywords: Australia ; forests ; fungi ; hypogeous ; mycorrhizae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hypogeous fungi are a large yet unknown component of biodiversity in forests of south-eastern mainland Australia. To better define their diversity and habitat relationships, we identified and counted fruit-bodies at 136 study sites sampling the climatic, geological and topographic features of the region. In one year 7451 fruit-bodies representing 209 species were collected in an autumn and spring sampling period. Only 57 of these species were previously described. Within genera, the number of species ranged from 1 to 21. Sites sampled in autumn averaged higher diversity of species and greater number of fruit-bodies than the same sites sampled in spring. Most major taxa occurred at more sites in autumn than in spring, whereas a few occurred more frequently in spring than in autumn. These patterns are consistent with those identified in previous smaller studies and likely reflect seasonal changes in soil moisture and temperature levels. Subsequent papers will explore factors influencing the occurrence, relative abundance and numbers of species of hypogeous fungi at the study sites and their community structure and possible host–plant relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008941906441
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