Culture Techniques for Rearing Soil Anthropods

Excerpt: Interest in soil biology has been prompted by recent investigations into the action of insecticides on plants and animals. Observations in the field must be supplemented by laboratory investigations conducted under controlled conditions. Consequently, it becomes necessary to rear and handle soil animals under artificial situations for bio-assay and life cycle studies. When large numbers of individuals are required, special problems in maintenance and manipulation arise. Relatively inexpensive and simple methods for such projects are essential and this paper describes some of those techniques which we have found expedient

The Deletion of the Bre1 Gene in Aspergillus nidulans Impairs Mitotic Growth, Meiosis, and DNA Damage Repair

Bre1 is a homotetrameric E3 ubiquitin-protein ligase that heterodimerizes with Rad6, an E2 ubiquitin-conjugating enzyme, in order to ubiquitinate lysine 123 in Aspergillus nidulans. This post-translational modification promotes methylation of lysines 4 and 79 on histone H3, which are required for certain damage repair pathways and for both optimal mitotic cell growth and meiosis [1-3, 12]. ΔBre1 mutants were generated by exposing protoplasts from strains auxotrophic for pyridoxine to a three-way fusion construct made from the Bre1 5’ and 3’ flanking regions and the Aspergillus fumigatus pyroA gene, which served as a selectable marker. Molecular diagnosis was confirmed via trans-locus PCR. Phenotypic analysis indicates that the loss of Bre1 increases sensitivity to DNA damage agents, decreases mitotic cell growth, and inhibits meiosis. The severe developmental defects of ΔBre1 mutants are consistent with the known roles of Bre1 as an upstream regulator of several important cellular functions. [excerpt

Asymptotics of Clebsch-Gordan Coefficients

Asymptotic expressions for Clebsch-Gordan coefficients are derived from an exact integral representation. Both the classically allowed and forbidden regions are analyzed. Higher-order approximations are calculated. These give, for example, six digit accuracy when the quantum numbers are in the hundreds.Comment: 30 pages, two figures. New Appendix added. Accepted for publication in the Journal of Mathematical Physic