John R. Obst

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Das Syringaaldehyd-azin ist eine hellgelbe, kristalline und leicht zu synthetisierende Verbindung, die in verdünnter alkoholischer Lösung von Laccase + Luftsauerstoff bzw. von Peroxydase + H2O2 unter Bildung eines intensiv purpurnen Pigments rasch oxydiert wird. Diese hochempfindliche Reaktion ist als Tüpfelprobe leicht anzuwenden und ergibt einen sehr(More)
Fungal laccase can be detected with the nonautooxidizable laccase­ specific compound, syringaldazine, in the presence of tyrosinase and per­ oxidase. Data are presented from tests with the azine derivative of numerous fungous sporophores and associated decayed wood tissues from various localities in Wisconsin and Oregon. Syringaldazine is shown to be a(More)
Raman microprobe spectroscopy was used to study the concentration of lignocellulosics in the cell corner middle lamella. Spectra obtained from 1.6 μm regions, from 30 cell corner middle lamellae of both birch and spruce, showed the presence of lignin. However, the relative concentration of lignin to cellulose varied considerably. These results corroborate(More)
An alkaline solution of purpald absorbs formaldehyde vapor quantitatively from air and turns purple. Under standard conditions, the intensity of the color can be used to measure release of formaldehyde from particleboard or fiberboard bonded with urea-formaldehyde or phenolformaldehyde resins. An airflow test and a spot test using purpald are outlined;(More)
Perhaps the most important aspect of plant cell wall research is that of analysis, both in the sense of quantitative determinations of cell wall components and structural characterization of these components. Whether one is investigating the aging of cell walls in corn (Zea mays L.) stover or determining the effect of phenolic acids on the digestibility of(More)
We appreciate the opportunity to address any ambiguities in our paper and to stress the nonuniform composition of cell corner middle lamellae. Dr. Goring is correct in stating that some cell corners of white birch are about 1 micron across. However, not all white birch cell corners are that small. Our measurements (taken by staff microscopist Thomas Kuster)(More)