Adaptations of skeletal muscle pyruvate dehydrogenase kinase in response to food-restriction in mitochondrial subpopulations

University, 2006 Dr. Sandra J. Peters Pyruvate dehydrogenase (PDH) catalyses the decarboxylation of pyruvate, to form acetyl-CoA. PDH activity is down-regulated by intrinsic PDH kinases (predominantly PDK2 and PDK4 isoforms), but the understanding of the PDK isoform distribution and adaptation to nutritional stresses has been restricted to mixed mitochondrial populations, and not delineated between subsarcolemmal (SS) and intermyofibrillar (IMF) subpopulations. SS and IMF mitochondria exhibit distinct morphological and biochemical properties; however the functional differences are not well understood. This study investigated the effect of fed (FED) versus 48 h total foodrestriction (FR) on rat red gastrocnemius muscle PDK2 and 4 isoform content in SS and IMF mitochondria. PDK4 content was ~3-5 fold higher in SS mitochondria compared to IMF (p=0.001), and increased with FR -3-4- fold in both subpopulations (p<0.001). PDK2 was -2.5-4 fold higher in SS mitochondria compared to IMF (p=0.001), but PDK2 was unaltered with FR. Citrate synthase activity (|imol/min/mg mitochondrial protein) was not different between either subpopulation. As well there were no significant differences between mitochondrial subpopulations in PDH complex components in both fed and FR states. These results demonstrate that there is a markedly higher content of both PDK isofonns in SS compared to IMF mitochondria. Although PDK2 does not increase in either subpopulation in response to FR, PDK4 increases to a similar extent in both SS and IMF after 48 h food-restriction.

An exploration of women elementary school teachers' perceptions of how their decision to return to teaching part-time from a maternity leave influences their professional and personal lives /

The purpose of this research was to explore women elementary teachers' perceptions of how their decision to return to teaching part-time from a maternity leave influences their professional and personal lives. The investigation focused on the decisions surrounding a mother's choice to reenter the teaching profession parttime in a field where each mother had previously been employed full-time. A collective case study was undertaken based on an in-depth interview with five mothers who had made the choice to return to the classroom part-time. The data collected in this study were analyzed and interpreted using qualitative methods. The following four major themes emerged from the interviews: decisionmaking process, challenges faced by mothers who teach part-time, the importance of support, and the enhancement of instructional practice from parenthood. Using these four themes, an analysis was conducted to examine the similarities and differences among the experiences of the participants. The mothers' reflections, my analysis, and the related literature were used at the conclusion of this report to compile implications for teaching practice, theory, and further research.

Letter to Mr. Walsh, Registrar Office, 1836

The man to whom the letter is addressed is Francis Leigh Walsh who was a land surveyor and registrar. Mr. Walsh was born on March 12, 1789 in Harford County, Maryland to Thomas Welsh, a United Empire Loyalist. In 1793, his family moved to Norfolk County and in 1810, Francis succeeded his father as registrar for Norfolk County. During the War of 1812 he served in the local militia and became a captain in 1824. He was the representative for Norfolk in the legislative assembly of Upper Canada from 1820 to 1828 and 1834 to 1836. He became justice of the peace in the London district in 1821 and 1838 in the Talbot district. He died in Simcoe on Oct. 14th, 1884. His son, Aquila Walsh served in the Legislative Assembly of the Province of Canada and in the Canadian House of Commons. Benjamin Hardison was born in Berwick in the Thirteen Colonies (British colonies on the Atlantic Coast of North America) on April 2, 1757 to Thomas Hardison and Mary Chadbourne. He was a farmer, miller and political figure. He was the representative for 4th Lincoln and Norfolk in the Legislative Assembly of Upper Canada from 1797-1800. On January 21, 1800 he married Jane Warren. He served with the American forces during the American Revolution at which time he was taken prisoner and sent to Canada. Later, he settled in Fort Erie where he was a captain in the militia and a justice of the peace for the Niagara district. He operated mills and a distillery in Fort Erie and died there on July 26, 1823. Source: http://en.vionto.com/show/me/Francis+Leigh+Walsh http://en.wikipedia.org/wiki/Benjamin_Hardison