Publish in OALib Journal
APC: Only $99
It is shown here that one can induce prematurely
condensed chromosomes (PCCs) in G1-phase human (HeLa) and mouse (FT210) cells
by treating them with the protein phosphatase inhibitor calyculin A. However,
histone H1 is not phosphorylated in these G1-PCCs.
It has previously been proposed that histone H1 phosphorylation is responsible for mitotic chromosome condensation,
but our results suggest that this is not the case. They indicate instead that
phosphorylation of histone H1 is not required for chromosome condensation. It
is known that the Cdk1 protein kinase, which triggers mitosis and also
phosphorylates histone H1, cannot be activated in G1-phase because mitotic cyclins are not present. Since
calyculin A induces PCCs in G1-phase in the absence of active Cdk1,
our results suggest that inactivation of protein phosphatases may be just as important
for the onset of chromosome condensation and other mitotic events as the
activation of protein kinases.
This paper examines the process of collecting data on New Orleanians affected by Hurricane Katrina. It does so by focusing upon the experiences of local researchers who were simultaneously conducting research on and within the disaster. It also documents one research team’s attempt to generate a random sample of residents from several New Orleans neighborhoods, stratified both by racial composition and level of damage. Further, it describes the challenges associated with navigating complex bureaucracies that are themselves affected by the disaster. Results demonstrate that our methods for drawing samples from six New Orleans neighborhoods yielded highly representative samples, even in heavily damaged neighborhoods where the long-term displacement required a multi-pronged strategy that involved contact by mail, telephone, and visits to local churches. The paper concludes by making recommendations for facilitating future research by locally affected researchers.