Release from meiotic arrest in ascidian eggs requires the activity of two phosphatases but not CaMKII.

The fertilising sperm triggers a transient Ca(2+) increase that releases eggs from cell cycle arrest in the vast majority of animal eggs. In vertebrate eggs, Erp1, an APC/C(cdc20) inhibitor, links release from metaphase II arrest with the Ca(2+) transient and its degradation is triggered by the Ca(2+)-induced activation of CaMKII. By contrast, many invertebrate groups have mature eggs that arrest at metaphase I, and these species do not possess the CaMKII target Erp1 in their genomes.

Studying mitotic checkpoint by illustrating dynamic kinetochore protein behavior and chromosome motion in living Drosophila syncytial embryos.

The spindle assembly checkpoint (SAC) mechanism is an active signal, which monitors the interaction between chromosome kinetochores and spindle microtubules to prevent anaphase onset until the chromosomes are properly connected. Cells use this mechanism to prevent aneuploidy or genomic instability, and hence cancers and other human diseases like birth defects and Alzheimer's. A number of the SAC components such as Mad1, Mad2, Bub1, BubR1, Bub3, Mps1, Zw10, Rod and Aurora B kinase have been identified and they are all kinetochore dynamic proteins.

The syphilis reactor grid: help or hindrance for syphilis surveillance?

Background: Health departments use reactor grids (sex, age, and serologic test for syphilis [STS] titer criteria) to determine which persons to evaluate for untreated syphilis.

Goal: The goal of the study was to assess reactor grid performance in Chicago and reactor grid use nationally in 1999 to 2000.

Study Design: We reviewed Chicago health department records to identify characteristics of persons with a reactive STS excluded from evaluation by reactor grid criteria and syphilis cases not meeting evaluation criteria.