High-level expression of the Endo-beta-N-acetylglucosaminidase F2 gene in E.coli: one step purification to homogeneity

The Endo F2gene was overexpressed in E.coli as a fusion protein joined to the maltose-binding protein. MBP-Endo F2was found in a highly enriched state as insoluble, inactive inclusion bodies. Extraction of the inclusion bodies with 20% acetic acid followed by exhaustive dialysis rendered the fusion protein active and soluble. MBP-Endo F2was digested with Factor Xaand purified on Q-Sepharose. The enzyme was homogeneous by SDS-PAGE, and appeared as a single symmetrical peak on HPLC. Analysis of the amino-terminus demonstrated conclusively that recombinant Endo F2was homogeneous and identical to the native enzyme.      

The migrations of the Red-billed Quelea Quelea quelea and their relation to crop damage

Recent studies on the migrations of the Red-billed Quelea Quelea quelea have shown that while the species is capable of long-distance movements of hundreds of kilometres, the actual migrations probably more often consist of shorter distances with a flexible timing. This flexibility allows adjustments to be made to the rainfall distribution in a particular year. New information comes from studies on the breeding distribution, on the plumage and moult of local populations, and from attempts to apply new techniques such as mass-marking with fluorescent particles. Breeding has been shown to be both more widespread and more frequent than previously recognized, while local populations can prolong breeding in one place if rainfall continues. Local populations have been identified that are apparently distinct, with limited intermixing with other populations, and some data suggest that intermixing may be reduced by flock or group cohesion. The flexibility of the migrations means that predictions of major influxes of quelea into agricultural areas have proved difficult to make, especially in regions where the rainfall patterns are complex and variable, such as East Africa.