Dating of ivory from 20th century by determination of ¹4C by the direct absorption method.

We aim to date ivory samples by determination of the concentration of (14)C in the sample. However, such data do not always represent unambiguous evidence. In these cases other nuclides have to be additionally analyzed which causes additional costs. To make the dating method still affordable, the direct CO(2) absorption method for analyzing (14)C was tested. Results show that this method has a precision of about 4.0% (95% confidence level) which is good enough for this purpose.

Interaction of HIV-1 Gag with the clathrin-associated adaptor AP-2.

The envelope glycoprotein (Env) of HIV-1 interacts with the clathrin-associated adaptor complex AP-2 during the late phase of the viral replication cycle. Upon its synthesis, Env, therefore, is retrieved from the cellular surface unless internalization is inhibited by viral Gag. Here we demonstrate that not only Env, but also HIV-1 Gag, specifically binds to AP-2. Gag-AP-2 association was found to depend on tyrosine residue 132 and valine residue 135 at the matrix-capsid junction in the Gag polyprotein. Results of a morphological analysis of viral egress from cells expressing dominant-negative AP-2 suggest an involvement of AP-2 in confining HIV-1 exit to distinct microdomains. Further, particle release from AP-2-mutant cells was enhanced compared to release from wild-type cells but the infectivity of virus released from these cells was moderately reduced. Together these data attribute a role to the AP-2 complex in the regulation of HIV-1 assembly/release.