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At least 1,225 records · Page 68Linked to original sources
PubMed2003

Releasing nitrogen from ammoniated lignin by white rot fungus cometabolizes environmental pollutants.

The nitrogen-modified lignocelluloses(NML) produced under oxic ammoniation was metabolized by white rot fungus, NH4(+) -N was released, NO3(-) -N concentration was decreased and total nitrogen loss was blocked within incubation period. During releasing nitrogen from the metabolism of NML, white rot fungus cometabolized recalcitrant environmental pollutants and showed higher degradation capability. Results indicated that this NML complex colonized by white rot fungus might be effective with economic feasibility when they are applied into the vast field ecosystem, it might stabilize NH4+ nitrogen flux and bioremediate the polluted environmental sites.

Ammonia↗
PubMed2005

[Identification of Regulatory Sequence of lip Genes of Phanerochaete chrysosporium under Lignin-degradation.].

Eleven subcloned DNA fragments from the 5'- upstream region of lipA, lipC and lipF of Phanerochaete chrysosporium were assayed by using the gel mobility shift assay(GMSA). The total proteins extracted from P.chrysosporium mycelia grown in Kirk medium and natural fir wood chip were used to identify the segments in these 11 DNA fragments which are controlled by some regulatory proteins. The results showed that two DNA segments LG2P3(396bp) and LG6S1-2 (738bp) in the 5'-noncoding regions of lipC and lipF were able to specifically bind total mycelial proteins of P. chrysosporium incubated in Kirk medium, separately. One DNA segment LG6S2 (226bp) from the 5'-noncoding region of lipF was found to specifically bind total mycelial proteins of this fungus on natural fir wood chip. Analysis of the sequences showed that there were many cis-regulatory elements in these DNA segments, implying that these sequences may be bound by some transcriptional regulation protein factors.

Base Sequence↗
PubMed1989

Thiol-mediated oxidation of nonphenolic lignin model compounds by manganese peroxidase of Phanerochaete chrysosporium.

In the presence of MnII, H2O2, and glutathione (GSH), manganese peroxidase oxidized veratryl alcohol (I) to veratraldehyde (IV). Anisyl alcohol (II) and benzyl alcohol (III) were also oxidized by this system to their corresponding aldehydes (V and VI). In the presence of GSH, chemically prepared MnIII or gamma-irradiation also catalyzed the oxidation of I, II, and III to IV, V, and VI, respectively. GSH and dithiothreitol rapidly reduced MnIII to MnII in the absence of aromatic substrates and the dithiothreitol was oxidized to its disulfide (4,5-dihydroxyl-1,2-dithiane). These results indicate that the thiol is oxidized by enzyme-generated MnIII to a thiyl radical. The latter abstracts a hydrogen from the substrate, forming a benzylic radical which reacts with another thiyl radical to yield an intermediate which decomposes to the benzaldehyde product. In the presence of MnII, GSH, and H2O2, manganese peroxidase also oxidized 1-(4-ethoxy-3-methoxy-phenyl)-2-(4'-hydroxymethyl-2'-methoxyphenoxy)- 1,3-dihydroxypropane (XII) to yield vanillyl alcohol (VII), vanillin (VIII), 1-(4-ethoxy-3-methoxyphenyl)-1,3-dihydroxypropane (XVI), 1-(4-ethoxy-3-methoxyphenyl)-1-oxo-3-hydroxypropane (XIX), and several C alpha oxidized dimeric products. Abstraction of the C alpha (A ring) hydrogen of the dimer (XII) yields a benzylic radical, leading to C beta oxygen ether cleavage. The resultant intermediates yield the ketone (XIX) and vanillyl alcohol (VII) or vanillin (VIII). Alternatively, benzylic radical formation at the C' alpha position (B ring) leads to radical cleavage, yielding a quinone methide and a C beta radical, which yield vanillin and the 1,3-diol (XVI), respectively. In these reactions, MnIII oxidizes a thiol to a thiyl radical which subsequently abstracts a hydrogen from the substrate to form a benzylic radical. The latter undergoes nonenzymatic reactions to yield the final products.

Aerobiosis↗
PubMed1989

Characterization of a cDNA encoding a manganese peroxidase, from the lignin-degrading basidiomycete Phanerochaete chrysosporium.

A cDNA clone of a manganese peroxidase (MnP) from Phanerochaete chrysosporium was isolated and characterized. The cDNA contains 1314 nucleotides excluding the poly(A) tail and the coding region has 68% G + C content. The deduced mature MnP protein contains 357 amino acids and is preceded by a 21-amino acid leader sequence. The experimentally determined N-terminal sequence of the purified MnP-1 protein, pI = 4.9, corresponds to the deduced N-terminal sequence of the gene. The Mr of the mature MnP-1 deduced from the cDNA is 37,439, which is approximately 81.4% of the experimentally determined molecular weight. The difference is due to glycosylation and a single potential N-glycosylation site with the general sequence Asn-X-Thr/Ser is present in the deduced MnP-1 sequence. Consistent with the peroxidase mechanism of MnP, the proximal histidine, the distal histidine, and the distal arginine are all conserved and regions flanking these residues display homology with other peroxidases. Northern blot analysis indicates that MnP expression is controlled by nutrient nitrogen at the level of transcription. Southern blot hybridization analysis suggests that MnP-1 is a member of a family of MnP genes.

Amino Acid Sequence↗