GENETICS OF SORDARIA FIMICOLA. III. CROSS-COMPATIBILITY AMONG SELF-FERTILE AND SELF-STERILE CULTURES

Carr , A. J. H. (Univ. Coll. Wales, Aberystwyth), and Lindsay S. Olive . Genetics of Sordaria fimicola. III. Cross compatibility among self-fertile and self-sterile cultures. Amer. Jour. Bot. 46(2) : 81-91. Illis. 1959.—Cross-compatibility in Sordaria fimicola is shown to be dependent upon a number of factors controlling the sexual process, from hyphal anastomosis and nuclear migration on through to perithecial formation and nuclear compatibility. Fertile cultures which were incompatible through inability to anastomose were induced to cross by the use of a third culture which would anastomose with both. Certain spontaneous or irradiation-produced sterility mutants were found to be compatible if the sterility genes were at different loci, through complementation by the wild-type alleles. In some pairings, cross-karyogamy was preferential, and in one case, only hybrid perithecia were produced. Fully fertile recombinants segregated from these crosses in frequencies which indicated that the sterility loci were unlinked. Certain sterility genes were found to influence hyphal anastomosis, nuclear migration, and the development of fertile sector heterokaryons from the zone of anastomosis. Mutant factors at two loci in a U.V. mutant causing self-sterility were found also to be responsible for lethality in ascospore germination. Factors in one sterility mutant controlled the production of a sterility-inducing substance which diffused into the medium. In some crosses, complementation of two sterile cultures towards fertility is shown to require a balanced nuclear ratio. Factors are described which increase the inhibitory effect of one sterility gene, while another factor was found to suppress its effect and thereby make the culture self-fertile. It is concluded that, since there is recombination between the sterility loci, these results do not represent the derivation of balanced heterothallism from a normally homothallic system, although it may lead by evolutionary progression to such a life cycle. The possible physiologic action of the sterility genes is discussed.     

Structural insights into the binding mode and conformational changes of BSA induced by bixin and crocin

Bixin and crocin are natural apocarotenoids utilized as food colorants and additives in food industries worldwide. For safety assessment, it is necessary to understand the biological interaction of food colorants. In our present study, we report the interaction of two apocarotenoids with bovine serum albumin (BSA) at physiological pH using spectroscopic techniques and in silico tools. The binding constant and the mode of binding sites have been studied. The enthalpic and entropic contribution to the intermolecular binding event was analyzed and it was found that the contribution of hydrogen bonding and hydrophobic interactions was dominant. The adverse temperature dependence in the unusual static quenching is found to be a reasonable consequence of the large activation energy requirement in the binding process, which is required to overcome the fundamental block and is a direct result of the unique microstructure of the binding sites. To confirm the experimental analysis, we investigated the binding patterns using different in silico tools. A combination of molecular docking, molecular dynamics, and toxicity analysis was performed, and the obtained results revealed that both the apocarotenoids had high binding affinity with a binding energy of ?5.44 and ?5.93 kcal/mol for bixin and crocin, respectively, with no toxic effects and are in accordance with our experimental analysis. The results directly revealed the flexibility of the protein toward bixin and crocin which has a great impact on the interaction. Thus bixin and crocin can guardedly be used as food colorants in food industries.     

Mixing characteristics of fixed film anaerobic reactors

Summary Since the mixing characteristics of anaerobic reactors would appear to have an effect on their operational performance, lithium tracer studies were made on two different digester types; the upflow sludge blanket and the expanded bed reactors. The mixing characteristics of both types of reactor, defined by this technique, were found to be of the intermediate type with a bias towards good mixing.     

Ueber Varietäten desLythrum Salicaria L.

Ohne Zusammenfassung     

Ueber Monstrositäten anBlechnum boreale undPolypodium,vulgare

Ohne Zusammenfassung     

Biochemical studies on muscarinic receptors

Muscarinic receptors have been characterized in smooth muscle and brain by the binding of reversible (e.g. atropine, quinuclidinylbenzylate) or irreversible (benzilylcholine or propylbenzilylcholine mustards) ligands. There is a close correlation between affinity constants derived from binding experiments and the affinities of muscarinic ligands for these sites obtained in pharmacological experiments on smooth muscle. Whereas atropine shows a single high affinity binding component (in subcellular preparations) several other ligands (QNB, ACh, oxotremorine) show multiple affinity binding. This indicated the existence of several types of binding sides which show selectivity toward certain cholinergic effectors. Most detergents inhibit the binding of ligands to the receptor site and therefore cannot be used to solubilize the receptor protein from the membrane. Treatment of brain subcellular membrane preparations with high salt concentrations (2M NaI) solubilize proteins which possess the muscarinic ligand binding properties observed in the membrane preparation. The affinities for muscarinic antagonists however are decreased, which suggests that a conformational change occurs in the protein upon solubilization.