Possible risperidone-induced visual hallucinations.
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Adolescent↗
Biomedical subjects
S Hird
Publications and source records attributed to S Hird.
Cortical actin movements during the first cell cycle of the Caenorhabditis elegans embryo.
The first division of the Caenorhabditis elegans embryo is unequal, generating daughter cells with distinct fates. The differences between the cells are believed to result from the partitioning of cytoplasmic determinants during the first cell cycle. Actin microfilaments play a critical, but poorly defined, role in this event. In this paper, the actin cortex in live embryos is studied during cytoplasmic localisation by fluorescently labelling microfilaments in oocytes and then using in vivo fluorescence microscopy to observe their behaviour. This reveals that there is a concerted movement of cortical actin to the anterior of the embryo at the time cytoplasmic localisation takes place. Furthermore, it is demonstrated that endogenous foci of F-actin are asymmetrically distributed following this event; these structures have previously been seen in fixed cortices. A model for the participation of the actin cytoskeleton in cytoplasmic localisation is presented based on these results.
Actins↗
Targeted mutations in the Caenorhabditis elegans POU homeo box gene ceh-18 cause defects in oocyte cell cycle arrest, gonad migration, and epidermal differentiation.
We used targeted gene inactivation to analyze the function of a Caenorhabditis elegans POU gene, ceh-18, and to dissect its functional domains in vivo. In ceh-18 mutants, oocytes exhibit an incompletely penetrant failure to arrest in diakinesis of meiotic prophase I and instead undergo multiple rounds of DNA replication without cytokinesis. ceh-18 is expressed in the gonadal sheath cells that signal the oocyte, but not in the oocyte. This suggests that ceh-18 affects, directly or indirectly, a sheath cell signal that causes oocytes to maintain diakinesis arrest. ceh-18 also participates in directing gonad migration and in specifying the differentiated phenotypes of epidermal cells during postembryonic development. Analysis of targeted deletions that disrupt half of the POU domain selectively by deleting either the POUhd or the POUsp alone, indicates that each CEH-18 POU subdomain is sufficient for partial activity in vivo.
Amino Acid Sequence↗