Circadian rhythms in biological processes occur in a wide range of organisms and are generated by endogenous oscillators. In Neurospora crassa, the FRQ-oscillator (comprised of FRQ, WC-1 and WC-2) is essential for rhythms in asexual sporulation and gene expression. How this oscillator signals to the cell to control rhythmicity is unknown. Furthermore, under certain growth conditions, rhythms are observed in FRQ-null strains, indicating the presence of one or more FRQ-less oscillators (FLOs). Interestingly, while circadian rhythms are observed in the related Aspergillus spp., they lack the frq gene, leading to the hypothesis that a FLO is responsible for rhythms in Aspergillus. Thus, Aspergillus provides a useful organism to investigate the components of the FLO. To investigate how an oscillator controls circadian output, we characterized the role of N. crassa NRC-2. The nrc-2 gene is under control of the clock and encodes a putative serine-threonine protein kinase. In a NRC-2-null strain cultured in low glucose conditions, FRQ-oscillator-dependent outputs are arrhythmic, but are rhythmic in high glucose. Our data suggests a model whereby NRC-2 relays metabolic information to the FRQ-oscillator to control rhythmic output. To understand the role of FLO(s) in the N. crassa circadian system, we examined regulation of the ccg-16 gene. We show that ccg-16 transcript rhythmicity is FRQ-independent, but WC-1-dependent. Furthermore, in contrast to current models for the FRQ-oscillator, we observed that rhythms in WC-1 protein accumulation persist in the absence of FRQ. These data support a new model involving two oscillators that are coupled through the WC-1 protein and that regulate different outputs. One approach to identify components of the FLO involved characterizing circadian rhythms in Aspergillus spp, which lacks FRQ. We find that A. flavus and A. nidulans, display circadian rhythms in sporulation and gene expression, respectively. Together, these findings provide a foundation for the identification of FLO components in both Aspergillus and N. crassa, that will ultimately lead to an understanding of how a multi-oscillator system can generate and coordinate circadian rhythmicity.

Thesis (M.A.) - Simon Fraser University, 2006. / Theses (Dept. of Psychology) / Simon Fraser University. Also issued in digital format and available on the World Wide Web.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 165-180). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39028

Thesis (M.S. in Human Systems Integration)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Miller, Nita Lewis. Second Reader: Schiffman, David L. "December 2009." Description based on title screen as viewed on January 26, 2010. Author(s) subject terms: Navy Standard Workweek, fatigue, sleep, circadian rhythm. Includes bibliographical references (p. 95-97). Also available in print.

Diel substrate preferences were tested in artificial stream experiments for six cyprinids: redfin shiner (Lythrurus umbratilis), silver shiner (Notropis photogenis), spotfin shiner (Cyprinella spiloptera), central stoneroller (Campostoma anomalum), striped shiner (Luxilus chrysocephalus), and bluntnose minnow (Pimephales notatus). We used experimental pools containing two of three substrate types (sand, cobble, and gravel) per trial to test if habitat preferences differed in day and night observations. Over 85% of specimens were observed over cobble substrate during the day, and all species switched substrate preferences at night for the tanks containing cobble. Our results suggest that day-night differences in habitat use may occur in other small-bodied species. Interpretations for habitat use of these species in the majority of studies that are based on daytime observations may need to be modified. Interpretations for habitat use by fish assemblages in the majority of studies that are based on daytime observations may need to be modified. / Department of Biology

Thesis (M App Sci in Physiotherapy) -- University of South Australia, 1992

Thesis (Ph.D.)--Tufts University, 2000. / Adviser: David Harder. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 90-116). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (M.S.)--Western Kentucky University, 2008. / Includes bibliographical references (leaves 54-57).

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Biochemistry." Includes bibliographical references (p. 121-135).