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M Luckner

Publications and source records attributed to M Luckner.

At least 37 records · Page 2Linked to original sources
PubMed1979

Phenol oxidase activity and pigment synthesis in conidiospores of Penicillium cyclopium.

Phenol oxidase (PO) of Penicillium cyclopium belongs to the laccases (E.C. 1.14.18.1). By PAA-gel electrophoresis three forms of the enzyme were detected. Most of the PO in emerged sporulating cultures accumulates in the cell wall of the conidiospores. However, a high percentage is not bound to the wall constituents and can be easily removed with aqueous solutions. This soluble fraction was 570-fold enriched by (NH4)2SO4-precipitation, followed by chromatography on sephadex G 200 and on hydroxylapatite-cellulose, The necessity of PO for conidiospore pigmentation was shown by means of suspended spores whose rates of pigment accumulation resemble those of conidia maturing in situ. Pigmentation is stopped if PO is inhibited by diethyldithiocarbamate. This corresponds to the fact that in strains with heavily pigmented conidiospores PO activity is much higher than in strains with weakly pigmented or unpigmented spores. Also the time course of PO accumulation in the latter strains is different from that of the former. Furthermore, in mutant res-eth 1 which has unpigmented conidiospores, PO isoenzyme no. 3 could not be detected.

Catechol Oxidase↗
PubMed1979

Structure and function of the conidiospore pigments of Penicillium cyclopium.

The cell wall of mature, green condiospores of Penicillium cyclopium Westling contains at least two pigments: A green chromoprotein which is extractable by means of formic acid or liquified phenol and a black insoluble pigment. Both fractions after long term treatment with boiling conc. HCl leave black amorphous residues which, due to their chemical and physico-chemical properties, belong to the group of melanins. The chemical structure of these melanins is still unidentified. No degradation products typical for indol-type or catechol-type melanins have so far been detected. During spore maturation parallel to an increase of pigmentation (determined by remission), the melanin residue left after acid hydrolysis of spores increases. The mature, dark green spores of the wild type strain contain about 40% melanin, the yellow-green spores of the mutant aux-glu 1 about 36%. The unpigmented spores of mutant res-eth 1 possess a melanin content of only about 5%. This value is nearly the same as that found in hyphae, which in all strains are yellowish-brown. The heavily pigmented condia of the wild type strain are about 100-times less sensitive to UV-radiation compared with the unpigmented spores of the mutant res-eth 1. The reduced sensitivity indicates that, as with other microorganisms, the conidia pigments of P. cyclopium are protective components of the spores.

Cell Wall↗
PubMed1978

[Selection and characterization of Penicillium cyclopium mutants with altered developmental program].

After treatment with NNMG, NaNO2 or UV-light of conidiospores of Penicillium cyclopium strain SM 72 variant strains (mutants) with altered developmental programme were selected. Additionally from a methionine-auxotrophic mutant of P. cyclopium prototrophic revertants were prepared. Investigation of the alkaloid metabolism and other idiophase processes has shown that these mutant strains can be divided into two groups (cf. table 1): a) Mutants with a depression of all idiophase features. The defects of these strains presumably affect central regulatory processes which, as in strain rev-met 83a, can be reversed spontaneously by an one-step mechanism and b) mutants defective in certain parts of the idiophase programme only, demonstrating that there is a certain autonomy in regulation of the individual parts of the programme.

Alkaloids↗