Polyporus versicolor

Growth of Polyporus versicolor in a Medium with Lignin as the Sole... 

Trametes (Polyporus) versicolor (Mad 697) Ponderosa pine 17 25 Goldstein eta/. (1961)... 

Ishikawa, H., W. J. Schubert, and F. F. Nord The Enzymatic Degradation of Softwood Lignin by White Rot Fungi. The Degradation by Polyporus versicolor and Forties fomentarius of Aromatic Compounds Structurally Related to Softwood Lignin. Arch. Biochem. Biophys. 100, 131-149 (1963). 

On adding dioxygen to the fully reduced laccase of the lacquer tree Rhus vemicifera, the type-1 Cu and the type-3 Cu-pair were oxidized in the ms range and an optical intermediate was observed at 360 nm At liquid helium temperatures an EPR signal was observed, which was tentatively interpreted as due to O ", as a result of its very short relaxation time and of the increase of its linewidth when the reduced laccase of the fungus Polyporus versicolor was treated with 0 A similar paramagnetic oxygen intermediate was also observed with the laccase of another lacquer tree Rhus succedanea and with ceruloplasmin. The decay of the intermediate at 25 °C (tj = 1 s at pH 5.5 with R. succedanea laccase) was accompanied by the reoxidation of the type-2 Cu >. One would expect, however, such an intermediate to be extremely reactive (See Sect. 3.3), while it was stable in tree laccase depleted of type-2 Cu(II)... 

Fungal Decay of Woods. Blocks of sweet gum and southern pine sapwood were inoculated with test fungi by the standard soil-block method (7). The test fungi were the brown rots Poria monticolla and Lentinus lepidius and the white rot Polyporus versicolor. As a control, one block of pine and one block of gum were left in the sterilized soil-block chambers in which the fungus had been started on feeder blocks and then sterilized. 

Douglas-fir, birch, southern pine, and sweetgum blocks were treated with 1% aqueous ammonia or sodium hydroxide for various times, temperatures, and pressures (9). These samples were submitted to soil-block tests with two brown-rot fungi Poria monticola (Madison 698) and Lentinus lepideus (Madison 534) and two white-rot fungi Polyporus versicolor (Coriolus versicolor) (Madison 697) and P. anceps (F 784-5) as well as outside exposure tests (10). In the soil-block tests, the treated wood was resistant to the two brown rotters, but was not resistant to the two white rotters. In the outdoor stake tests, the average lifetime was 3.5 years while untreated controls had an average lifetime of 3.6 years. The outdoor tests show that there is no increase in rot resistance by this treatment. 

C. Heat Treatments. Several woods have been heated under wet and dry heating conditions to determine the effect heat has on the decay resistance of these woods. Alaska-cedar, Atlantic white-cedar, bald cypress, Douglas-fir, mahogany, redwood, white oak, Sitka spruce, and western redcedar were heated under dry conditions or wet conditions at temperatures of 80-180°C for varying lengths of time. Boyce (11) found that dry heat at 100°C or steam heat at 120°C for 20 minutes had no effect on the decay resistance. Similar results were observed by Scheffer and Eslyn (12) in soil-block tests with Lenzites trabea for the heated softwoods and Polyporus versicolor for the heated hardwoods. 

We illustrate these aspects of metalloprotein dynamics at surfaces by two specific proteins. One is the two-centre bacterial di-heme protein cyt c4 from Pseudomonas stutzeri, and the other is the fungal four-centre redox enzyme laccase from Polyporus versicolor. 

Laccase Polyporus versicolor 02 Absorption maximum at 360 nm, new EPR signal at low temperature (lO K) 0" radical 6l5-nm band, 5 x 10 Af sec"330-nm band, 5 > lO M sec 360-nm absorption maximum. 5 x 10 Msec" type-2 copper EPR signal, 20-8 halftime Absorption maximum at 360 nm. 20-s halftime, first-order reaction [Pg.161]

Laccase Polyporus versicolor) obscured by blue copper ... 

Figure 1. Visible CD (A) and absorption spectra (B) of azurin from Pseudomonas aeruginosa (left) and laccase from Polyporus versicolor...

Laccase, 1.10.3.2, Rhus vernicifera, Coriolus hirsitus, Polyporus versicolor... 

The redox potential of the Tl Cu-site has been determined using potentiometric titrations with redox mediators for a large number of different laccases and varies between 410 mV vs. NHE for Rhus vernicifera [67] and 790 mV for laccases from Polyporus versicolor and Coriolus hirsutus [244,251]. The T2 and T3 sites have higher potentials [251]. 

Figure 5. Cellulose in wood is depolymerized early during brown rot, but only gradually during white rot. The data are for sweetgum sapwood decayed by the brown-rot fungus Poria placenta (Fr.) Cke. (formerly P. monticola Murr.) and for the white-rot fungus Coriolus versicolor (L. ex Fr.) Quel, (formerly Polyporus versicolor L. ex Fr.) (15).

Faced with the problem of elucidating the individual roles of the diflFerent copper centers in the blue oxidases, the researcher has naturally focused in recent years on the laccases (9). Being easier to isolate, better characterized, and containing fewer copper atoms than cemloplasmin or ascorbate oxidase, the laccases from the Japanese lacquer tree Rhus vernicifera and the fungus Polyporus versicolor have been the subject of several transient kinetic studies in the millisecond range, that is, studies using stopped-flow spectrophotometry and rapid-freeze EPR spectroscopy (9,49,50). 

R Schmid, W Liese. Uber die mikromorphologischen Veranderungen der Zellwandstrukturen von Buchen- nnd Fichtenholz beim Abbau durch Polyporus versicolor (L.) Fr. Arch Mikrobiol 47 260-276, 1964. 

For the concentration of enzyme solutions it is important to use methods giving the highest possible yield of enzymic activity—i.e., loss of activity should be brought to a minimum. None of the above methods will in all cases fulfill these requirements since denaturation and consequently low yield of enzymic activity are reported for all these methods. To avoid denaturation owing to precipitation as well as owing to freezedrying and evaporation, Petterson et al. (39) introduced the dextran gel concentration method of Flodin et al. (12) into cellulase research. This method was found to give essentially quantitative recovery of cellulase activity from culture solutions of Polyporus versicolor. 

Gel Filtration Technique. Cellulases were among the first proteins to be separated by the gel filtration technique. Cellulolytic enzymes from Polyporus versicolor were thus separated by Pettersson et ah (39) on Sephadex G-75 (Pharmacia Fine Chemicals, Uppsala, Sweden) and simultaneously Whitaker et ah (56) applied the same technique in studies on the cellulolytic enzymes from Myrothecium verrucaria. The gel filtration method has since been so frequently used in separation and... 

Figure 8. Longitudinal section of sweetgum sapwood (Xiquidambar styraciflua L.) decayed by Polyporus versicolor L. Note evidence for enzymatic disintegration of the cell walls between contiguous fiber tracheids in the immediate vicinity of the bore holes formed by hyphae in passing from one cell to another. Note similar loosening of the cell wall material also along lumen surfaces at some distance from the bore holes. The hypha in the largest bore hole apparently is in the process of autolysis...

One possible explanation for these different modes of cellulose depolymerization in the same species of wood is that the cellulolytic enzyme molecules of Poria monticola are smaller than those of Polyporus versicolor and for that reason would be able to penetrate and act in regions of the fine structure of the fibers that are not accessible to those of the latter fungus. This hypothesis has led to efforts (as yet incomplete) to determine the molecular size of the cellulolytic enzyme proteins of these two organisms. Another possible explanation is that the initial dissolution of cellulose and other cell-wall polysaccharides is accomplished by catalysts that are not enzyme proteins and therefore could be substantially smaller in molecular size. Halliwell (21) has described experiments on the... 

The slow, gradual decrease in DP of holocellulose in the case of the white-rot fungus, Polyporus versicolor, indicates that the organism degraded the crystalline and amorphous cellulose simultaneously and at rates proportional to the amounts originally present. This conclusion was confirmed by moisture regain and x-ray diffraction analyses (8). 

Brown The determinations of size of the cell-wall capillaries and the cellulases of fungi indicate that the enzymes that have been isolated to date are so large that they probably can penetrate only a few cell-wall capillaries in wood and cotton. This conclusion is supported by Cowling s DP data for the action of the white-rot fungus, Polyporus versicolor, on wood (Figure 13). But it is also contradicted by the same type of data for the effect of both the brown-rot fungus, Poria monticola, on wood (Figure 13) and of Myrothecium verrucaria on mercerized cotton as shown by Selby (60). Thus we believe that the catalysts responsible for the initial depolymerization of cellulose in wood and cotton by these two... 

Figure 2. Comparison of rate of decay of dilute NaOH-treated (and washed) sugar maple with that of untreated wood by three types of fungi White rot, Polyporus versicolor brown rot, Lenzites trabea and soft rot, Graphium sp.

WHITE-ROT FUNGAL DEGRADATION (Polyporus versicolor on Sitka Spruce)... 

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