Chimpanzee-origin adenovirus vectors as vaccine carriers.

Vaccines based on replication-defective adenoviral vectors are being developed for infectious agents and tumor-associated antigens. Early work focused on vaccines derived from a common human serotype of adenovirus, that is, adenovirus of the serotype 5 (AdHu5). Neutralizing antibodies against AdHu5 virus, present in a large percentage of the human population, dampen the efficacy of vaccines based on this carrier. To circumvent this problem, we generated vectors derived from chimpanzee adenoviruses. Here we describe some basic parameters of vectors derived from chimpanzee adenoviruses C68 and C7, including growth characteristics, yields of infectious particles, effects of additional deletions in E3 and E4 and lengths of the inserted foreign sequence as they relate to the suitability for their eventual development as vaccine carriers for clinical use.

Nest-Site Selection by black sparrowhawks Accipiter melanoleucus: implications for managing exotic pulpwood and sawlog forests in South Africa.

This study provides timber growers with silvicultural guidelines for establishing and maintaining nest-tree habitat for native black sparrowhawks (Accipiter melanoleucus) in commercial planted forests in South Africa. In this country, exotic eucalypts and pines are planted principally for pulpwood and sawlog production. Nineteen nests were sampled in indigenous forests and 58 nests in exotic forests. Although mean nest heights differed between indigenous and exotic trees, in all trees, nests were positioned, on average, at 64% of tree height. Black sparrowhawks nested near stand edges, probably seeking a compromise between nesting adjacent to open hunting habitat and selecting an insulated tree from within the forest. Black sparrowhawks nested in tall trees ( X- = 18-33 m for different tree species classes) with a large diameter (>60 cm). Unfortunately, the South African pulpwood and sawlog industry employ short rotations (<16 years) and high tree densities (>700 trees/ha) that do not allow the trees to attain the characteristics suitable for black sparrowhawk nesting sites. Eucalypt and pine nest stands must be of 25 x 25 m minimum size and incorporate 10 trees at minimum heights of 21 and 18 m and diameters of 37 and 35 cm, respectively. If such nest-tree stands are set aside as islands in a sea of commercial forests, and black sparrowhawks and other forest raptors nest in them, timber growers will improve the tree-nesting raptor diversity of planted forests. If, however, these raptors prey upon species of conservation importance, the management recommendations could be reversed to limit the potential for predation.