An examination of stress in college students over the course of a semester.

The purpose of this study was to determine whether differing stress reduction interventions could alter stress levels experienced by male and female college students from the beginning to the end of a semester. Components of stress examined included overall perceived stress, test anxiety, and personal burnout. Participants (N = 531) were part of courses that during the course of a 16-week semester focused specifically on cognitive-behavioral stress management, cardiovascular fitness, generalized physical activity, or a control with no intervention. In addition to gender differences, both the stress management and physical activity groups had significantly lower levels of perceived stress, test anxiety, and personal burnout at the end of the semester. The fitness group scored significantly lower on perceived stress and personal burnout, but there was no difference in scores for test anxiety. The important ramifications of reducing stress in college students are discussed, including the pros and cons of implementing differing physical and psychological intervention modalities.

Genomic structure and embryonic expression of estrogen receptor beta a (ERbetaa) in zebrafish (Danio rerio).

Estrogenic steroid hormones mediate complex actions important in both embryonic and adult life. The hormones signal through ligand-inducible transcription factors known as estrogen receptors (ERs). In this study, we have isolated a zebrafish estrogen receptor with homology to human estrogen receptor beta (ERbeta). This zebrafish ERbeta (ERbetaa) has a conserved genomic structure of eight coding exons with boundaries similar to those of human ERbeta. The coding exon structures of two other zebrafish estrogen receptors (ERalpha and ERbetab) are presented as well. We also analyzed 3.3 kb of the promoter region and identified numerous putative transcription factor binding sites, including SP1 and ER half sites. Zebrafish ERbetaa message RNA is maternally loaded, but quickly degraded after fertilization, as detected by reverse transcriptase polymerase chain reaction. ERbetaa transcripts are detected again between 24 and 48 h post fertilization. These results indicate that ERbeta has been highly conserved during evolution and is likely used during later embryogenesis in zebrafish. Future identification of the expression levels and patterns of this and other estrogen receptors in zebrafish will allow a better understanding of estrogen signaling during embryogenesis.

Identification and characterization of a functional zebrafish smrt corepressor (ncor2).

The retinoic acid receptors (RARs or rars) and the thyroid hormone receptors are members of the steroid receptor superfamily that interact with their DNA response elements (for RARs: retinoic acid response elements or RAREs) in the regulatory regions of promoters in the absence of their ligand. In this ligand minus configuration, it has been suggested that the RAR provides a binding site for a corepressor (SMRT or N-CoR) that also brings in other proteins to repress the gene. In the presence of the ligand, the receptor goes through an allosteric change eliminating the corepressor binding site and providing a coactivator binding site. In this manuscript we describe the isolation of the zebrafish corepressor, smrt. We show that its association with the zebrafish rar aa is sensitive to retinoic acid and that the corepressor mRNA is present in 8 cell zebrafish embryos - a time at which the embryonic genome is not active. We suggest that this rar-corepressor complex may be part of an embryonic, epigenetic switch that keeps retinoic acid responsive genes off before retinoic becomes available to the embryo.