Biomedical subjects

S Staab

Publications and source records attributed to S Staab.

3 recordsLinked to original sources

PubMed1996

Female germ cells of Drosophila require zygotic ovo and otu product for survival in larvae and pupae respectively.

Mutations in the genes ovo or otu can cause abnormal proliferation of XX germ cells, which leads to so-called ovarian tumors, or they can lead to the elimination of XX germ cells, such that adult females possess empty ovaries. Males carrying ovo or otu mutations are unaffected. To find out when this sexual dimorphism affects germ cells, we analyzed the requirement of embryos and larvae for zygotic ovo and otu products. We found that ovo is required for the survival of XX germ cells during larval stages, while XX germ cells lacking otu survive until metamorphosis. Furthermore, we found no sex-transformed mutant larval germ cells and no evidence for an early sex-specific vital process acting in germ cells of the embryo, contrary to what had been suggested earlier.

Animals↗

PubMed1996

Somatic sex-determining signals act on XX germ cells in Drosophila embryos.

In Drosophila, the enhancer-trap line mgm1 is already specifically expressed in male germ cells. Staining is first detected in 10-hour-old embryos and it is found in later stem cells. This line, which reveals the earliest sex-specific gene expression in the germline known so far, is a useful molecular marker to assess the sexual pathway that germ cells have entered before any overt sexual dimorphism is apparent. XY germ cells that develop in feminized animals express mgm1, which shows that this marker is autonomously expressed in XY germ cells. However, XX germ cells that develop in masculinized animals also express mgm1. Therefore, somatic sex-determining signals have already acted on XX germ cells in 10-hour-old embryos.

Animals↗

PubMedDate not supplied

Examining competency-based orientation implementation.

A competency-based orientation program provides a structured, comprehensive approach to the process of orientation. However, the program is only as good as the implementation. It is important for management, preceptors, and orientees to be knowledgeable of the details of the program and the procedures involved in the implementation process. when problems arise, it is important that all those involved solve the problems in an organized, systematic fashion.

Clinical Competence↗