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  • Fungal melanins  (2)
  • Carbon  (1)
  • Epidemiology  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 5 (1987), S. 120-125 
    ISSN: 1432-0789
    Schlagwort(e): Fungal melanins ; Humic acid ; Infrared analysis ; Free radicals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Humic acid-type polymers (melanins) synthesized in culture media by the fungi Aspergillus glaucus, Eurotium echinulatum, Hendersonula toruloidea, Stachybotrys atra and Aspergillus sydowi were analysed for elemental composition, functional group content, infrared (IR) and electron spin resonance (ESR) properties. Results were discussed in comparison with range values referred for soil humic acids. The fungal polymers showed significant differences in carboxyl and nitrogen content and C/H atomic ratios, reflecting a different degree of condensation (aromaticity) among the various samples. IR analysis gave evidence of: (a) the predominant aromatic character of melanins from A. glaucus, E. echinulatum and H. toruloidea; (b) the high content of aliphatic and olefinic components of S. atra melanin; (c) the typical presence of amide bonds in the nitrogen-richest melanins from A. sydowi and H. toruloidea; and (d) the generally low amount of free carboxyl groups, which often appeared involved in hydrogen bonds. ESR spectra showed that all the melanins studied contained appreciable concentrations of organic free radicals of prevailing semiquinonic nature and of the same order of magnitude commonly measured in humic acids from soil and other sources. The free electron concentration was shown to be directly related to the C/H atomic ratio and to the degree of aromaticity shown by IR analysis. This indicated that the highest free radical content in the melanins from E. echinulatum and A. glaucus was associated with the highest presence of condensed aromatic structures. Humic acid-type polymers synthesized by soil fungi may, therefore, contribute to the total free radical content of soil humic substances and play important roles in all reactions involving free radicals in soils and related environments.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 10 (1990), S. 72-76 
    ISSN: 1432-0789
    Schlagwort(e): Brazilian soils ; Fungal melanins ; Soil humic acid ; Infrared analysis ; Latosols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Humic acids from two Brazilian topsoils under savanna grassland and five soil fungal melanins were characterized by elemental, functional group and infrared analysis. C, N, total acidity, COOH, and phenolic OH contents were within the ranges reported for several other fungal melanins and soil humic acids. Compared with the soil humic acids, the infrared spectra of the fungal melanins showed greater detail, indicative of higher aliphaticity. They were similar to the type III infrared spectra of humic acids, which are characteristically high in proteinaceous material and polysaccharides. The infrared spectra of the humic acids from the two Brazilian soils studied were classified as type I, which includes most soil humic acids. Notwithstanding the greater detail, in some areas the fungal melanin spectra were similar to those reported for other fungal melanins and humic acids of different origins. The probable contribution of the melanic fungi to the formation of soil humic polymers is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-5036
    Schlagwort(e): Biodegradation ; Biomass ; Carbon ; Cornstalks ; Humus formation ; Wheat straw
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The effect of soil type and incubation period on the biodegradation, incorporation into biomass, and stabilization in humus of14C-labeled cornstalk and/or wheat straw lignin, polysaccharide, and protein fractions were followed for one year. After 6 months, 56–68%, 6–21%, 71–81%, 63–75%, and 56–68% from wheat straw and from the lignin, polysaccharide, and protein fraction of wheat straw had been lost as CO2, respectively. Loss of CO2 increased only slightly with further incubation. Greater amounts of CO2, especially during the early incubation stages, were evolved from neutral and alkaline soils (pH 7.0, 7.4, 7.8) than from acid soils (pH 5.0, 5.5). After one year, a major portion of the residual C from lignin was recovered in the humic acid fraction, relatively small amounts, 5 to 17%, were lost upon acid hydrolysis, and generally 〈1% was found present in the biomass. Lesser amounts of the polysaccharide and protein carbons were incorporated into the humic acid, 17–20% and 16–27%, respectively. Relatively greater amounts of the residual carbons of the polysaccharide and protein were incorporated into the biomass, 4.9–7.8% and 4.6–13.4%, respectively and higher percentages were lost upon acid hydrolysis, 56 to 81%. The results for the whole wheat straw were very similar to those of the protein fraction. Overall, more residual C was stabilized into humic acid in the acid soils than in the neutral soils.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 4 (1988), S. 39-44 
    ISSN: 1573-7284
    Schlagwort(e): Epidemiology ; Occupational pathology ; Chronic bronchitis Iron miners ; Protease inhibitor (Pi) phenotype
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Pi phenotype was determined and α1 protease inhibitor (α1Pi) was measured in 871 iron-ore miners examined twice at five years interval. A questionnaire on respiratory symptoms was administered and lung function tests: spirometry (VC, FEV1.0), measurements of the residual volume (RV/TLC) and of the CO diffusion (FuCO), were carried out by the same medical and technical team, using the same apparatus. There were no differences in age, lenght of employment or smoking habits among the three Pi Phenotype groups: M (90:03%), MS (7.1%), MZ (2.8%). The prevalence of clinical symptoms at the initial survey and the incidence of symptoms between the 2 surveys were not related to Pi Phenotype groups. However a significantly steeper decline of FEV1.0/VC was observed in the α1Pi partially deficient groups MS and MZ (−3.9%) compared with the non-deficient group (−1.8%). No significant difference was observed for VC, RV /TLC and FuCO. This finding suggests that an intermediate deficiency of α1Pi may be related to a slight but statistically significant impairment of a lung function in occupational conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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