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51.
52.
Various basidiomycetes, ascomycetes, and deuteromycetes, grown in a sugar-rich liquid medium, were compared for laccase-producing ability and for the inducing effect of 2,5-xylidine on laccase production. Clear stimulation of the extracellular enzyme formation by xylidine was obtained in the cultures of Fomes annosus, Pholiota mutabilis, Pleurotus ostreatus, and Trametes versicolor, whereas Rhizoctonia praticola and Botrytis cinerea were not affected by the xylidine, and in the case of Podospora anserina a decrease in laccase activity was observed. The laccases were purified, and electrophoresis on polyacrylamide gels indicated a particular pattern for each laccase. The bands of the induced forms appeared only with basidiomycetes. The optimal pH of R. praticola laccase was in the neutral region, whereas the optima of all the other exolaccases were significantly lower (between pH 3.0 and 5.7). All laccases oxidized the methoxyphenolic acids under investigation, but there existed quantitative differences in oxidation efficiencies which depended on pH and on the nature (noninduced or induced) of the enzyme. The sensitivity of all enzymes to inhibitors did not differ considerably. 相似文献
53.
Andrzej J. Żelazowski Jadwiga A. Szymańska Czesklaw S. Cierniewski 《Chemico-biological interactions》1980,33(1):115-125
Two homogenous fractions of hepatic metallothioneins ((Cd,Zn) MT-1 and (Cd,Zn) MT-2) and renal metal binding proteins ((Bi,Cu) BP-1 and (Bi,Cu) BP-2) were isolated from rats exposed to heavy metals and specific antisera to them were produced in rabbits.These antisera were tested by immunodiffusion and immunoelectrophoresis for their ability to bind different fractions of hepatic Cd,Zn -metallothionein and renal (Bi,Cu)-, (Hg,Cu)- and (Cd,Cu)-binding proteins. It was found that anti (Bi,Cu) BP antisera did not cross-react with hepatic (Cd,Zn) MT-1 and (Cd,Zn) MT-2. Strong immunological cross-reactions were detected between anti (Bi,Cu) BP antisera and individual forms of (Cd,Cu)-, (Hg,Cu)- and (Bi,Cu)-binding proteins isolated from rat kidneys. 相似文献
54.
55.
Andrzej Paszewski Wiesawa Pramo Magorzata Landman-Baliska 《Molecular & general genetics : MGG》1977,155(1):109-112
Summary Mutants of Aspergillus nidulans blocked in the main pathway of cysteine synthesis show an elevated level of the enzymes involved in the synthesis of cysteine from homocysteine i.e. cystathionine -synthase and -cystathionase and a depressed level of homocysteine methyltransferase. This results in a considerable change in the sulfur amino acids pool as compared to the wild type. Upon addition of cysteine to the growth medium the first two enzymes are repressed while the level of the third one increases. These data indicate that the two diverging pathways of homocysteine metabolism are anti-coordinately regulated. 相似文献
56.
Summary The nervous system of the most primitive fresh-water Turbellaria of the order Catenulida was investigated. Neurosecretory
cells were found to occur in it. These cells have a structure similar to that of nerve cells, they only differ by the presence
of neurosecretion granules and a more developed golgi complex. In the simplest Catenulida,Stenostomun, neurosecretory granules are found both in the brain cells and in the trunks in the nerve fibres where they are rather randomly
distributed. Another representative of this family, the more highly organizedCatenula, exhibits specialized brain and nerve trunk regions containing neurosecretion granules.
This work was supported in part by the Committee on Cytobiology of the Polish Academy of Sciences 相似文献
57.
Andrzej Myśliwski Jolanta Myśliwska Zbigniew Kmieć 《Histochemistry and cell biology》1977,52(1):91-96
Summary A comparsion of the Feulgen hydrolysis curves and the chromatin compactness of the liver cell nuclei of young and old rats was made. It was found that the rate of DNA depurination and chromatin compactness are higher in the liver cell nuclei of old rats, both in di-and tetraploidal cells. The effect of fixation upon the course of the hydrolysis curves is discussed.This investigation was supported by grant 474/VI Committee of Cell Pathology, Polish Academy of Sciences 相似文献
58.
Some opiates with morphinan- and benzomorphan-structures possess affinities for neuroleptic receptors as revealed by their abilities to compete with 3H-spiroperidol for common binding sites in rat striatum (IC50 in the range between 10?6 and 10?5M). The binding of these opiates to neuroleptic receptors appears to be of pharmacological significance, since studies in mice revealed a small but significant displacement of spiroperidol by high doses of the opiate antagonist levallorphan from specific binding sites in the striatum. In addition, there exists some correlation between the ability of opiates to bind to neuroleptic receptor sites and their potency to evoke “bizarre behavior” in rats . In contrast, a wide variety of other opiates having morphine-, morphinone- or oripavine-structure showed no affinity for neuroleptic binding sites (IC50 greater than 10?4 M). Of the opioid peptides (methionine-enkephalin, leucine-enkephalin and β-endorphin) none has an affinity for neuroleptic binding sites. A variety of other peptides were also investigated but did not interfere with spiroperidol binding. Only ACTH showed a moderate affinity for neuroleptic binding sites. 相似文献
59.
CD study of four modified nucleosides, constituents of tRNA molecules, revealed that 2-thio-5-methyluridine and 5-methyluridine in aqueous solution, 0.1N HCl, and organic solvents essentially occur in an anti-conformation. 5-Methylcytidine also occurs in an anti-conformation similar to cytidine in aqueous solution and organic solvents, while 2-thiocytidine dihydrate appears to occur in an anti-conformation. It is stressed that the CD data of thionucleosides might be applied to the successfully conformational analysis of tRNA molecules. 相似文献
60.
Marsha E. Daman Ron L. Batstone-Cunningham Robert E. Hardy Kilian Dill 《International journal of biological macromolecules》1983,5(6):371-373
13C-n.m.r. spectral data for 13C reductively methylated intact homozygous and heterozygous glycophorins A were compared with the 13C-n.m.r. spectral data for the 13C reductively methylated homozygous and heterozygous N-terminal glycopeptides derived from the trypsin digest of glycophorin A. The results indicate that pronounced aggregation of this glycoprotein in solution does not affect the structural differences that we have previously observed for glycophorins AM and AN at and/or near the N-terminal amino acid. Moreover, the data suggest that two structural states exist for glycophorin AM. 相似文献