Screening method for microorganisms producing L-aminoacids from D,L-5-monosubstituted hydantoins

Summary The ability of microorganisms to produce hydantoinase and L-N-carbamoylase could be established by an overlay assay. Enzyme producing strains form clear areas around their colonies caused by the cleavage of D,L-indolylmethylhydantoin. A second overlayer with a tryptophan-auxotroph yeast enables us to detect microorganisms which are able to produce L-tryptophan from D,L-indolylmethylhydantoin.     

Decreased Laminin Expression by Human Lung Epithelial Cells and Fibroblasts Cultured in Acellular Lung Scaffolds from Aged Mice

The lung changes functionally and structurally with aging. However, age-related effects on the extracellular matrix (ECM) and corresponding effects on lung cell behavior are not well understood. We hypothesized that ECM from aged animals would induce aging-related phenotypic changes in healthy inoculated cells. Decellularized whole organ scaffolds provide a powerful model for examining how ECM cues affect cell phenotype. The effects of age on ECM composition in both native and decellularized mouse lungs were assessed as was the effect of young vs old acellular ECM on human bronchial epithelial cells (hBECs) and lung fibroblasts (hLFs). Native aged (1 year) lungs demonstrated decreased expression of laminins α3 and α4, elastin and fibronectin, and elevated collagen, compared to young (3 week) lungs. Proteomic analyses of decellularized ECM demonstrated similar findings, and decellularized aged lung ECM contained less diversity in structural proteins compared to young ECM. When seeded in old ECM, hBECs and hLFs demonstrated lower gene expression of laminins α3 and α4, respectively, as compared to young ECM, paralleling the laminin deficiency of aged ECM. ECM changes appear to be important factors in potentiating aging-related phenotypes and may provide clues to mechanisms that allow for aging-related lung diseases.     

Über die Mitosenverteilung im Meristem der Wurzelspitzen

Ohne ZusammenfassungMit 11 Textabbildungen.     

Leishmania tarentolae: proline anabolism in promastigotes.

Using ¹⁴C-labeled substrates in conjunction with thin-layer Chromatographic radioautography, studies were done to determine the precursors for proline synthesis utilized by promastigotes of Leishmania tarentolae. The only substances in Trager's Defined Medium capable of acting as proline precursors under the conditions studied were l-arginine and l-ornithine. None of the other substrates tested (16 amino acids, five purines and pyrimidines, and glucose) were converted to proline. l-glutamate, l-aspartate, and d-glucose did not act as precursors for the imino acid although they stimulated oxygen uptake better than did l-arginine and l-ornithine. Proline synthesis was unaffected by the presence of preformed proline indicating the absence of end product feedback inhibition.     

Mechanism of activation of the protein kinase I from rabbit skeletal muscle. The high-affinity ATP site of the holoenzyme.

The high-affinity binding site for ATP of the holoenzyme of cAMP-dependent protein kinase (type I) from rabbit skeletal muscle has been investigated. Binding affinity of a series of ATP derivatives substituted at different sites in the molecule was determined by competition with tritiated ATP. The results were compared with data available from cAMP derivatives with the same substituents, in order to analyse the electronic and steric features of these two sites on the protein kinase. The comparison revealed significant differences of the effect of substituents towards the two sites. In particular the N6-derivatives of ATP and substituents affecting the gamma-phosphate indicate that the high-affinity ATP site of the protein kinase has similar properties as those found for phosphotransferase sites. The present results are consistent with the supposition that the high-affinity site for ATP on the holoenzyme is congruent with the phosphotransferase site of the catalytic subunit. Upon combination of catalytic and regulatory subunits this site would be transformed into a high-affinity site for ATP with simultaneous blocking of the phosphotransferase activity.     

Zum Generationswechsel vonMelampsora tremulae Tul

Ohne Zusammenfassung     

Zur Kenntnis desSaruma Henryi Oliv

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