Global ETD Search

1	The Allometry of Giant Flightless Birds Dickison, Michael R., January 2007 (has links) (PDF) Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.
2	Role of Flightless I in Cell Migration Mohammad, Ibrahim 12 January 2011 (has links) A central process in connective tissue homeostasis is cell migration, which involves dynamic interactions between focal adhesions, the actin cytoskeleton and mitochondria, but the role of focal adhesion proteins in cell migration is not wholly defined. We examined focal adhesion-associated proteins from mouse fibroblasts and identified Flightless I (FliI) as a potential focal adhesion protein. We determined that FliI is distributed in the cytosol and co-localizes with actin monomers and mitochondria, but partially with paxillin. Biochemical assays showed that FliI associates with both actin monomers and short oligomers/filaments. Migration assay determined that cells with reduced FliI expression migrated more quickly and that FliI knockdown inhibited activation of β1 integrins. Consistent with these data, cell adhesion assay demonstrated that FliI knockdown cells were less adherent than wildtype cells. Our findings indicate that FliI may regulate cell migration by interacting with the actin monomers and the mitochondria to affect cell adhesion. flightless I cell migration actin cytoskeleton mitochondria cell adhesions 0567
3	Role of Flightless I in Cell Migration Mohammad, Ibrahim 12 January 2011 (has links) A central process in connective tissue homeostasis is cell migration, which involves dynamic interactions between focal adhesions, the actin cytoskeleton and mitochondria, but the role of focal adhesion proteins in cell migration is not wholly defined. We examined focal adhesion-associated proteins from mouse fibroblasts and identified Flightless I (FliI) as a potential focal adhesion protein. We determined that FliI is distributed in the cytosol and co-localizes with actin monomers and mitochondria, but partially with paxillin. Biochemical assays showed that FliI associates with both actin monomers and short oligomers/filaments. Migration assay determined that cells with reduced FliI expression migrated more quickly and that FliI knockdown inhibited activation of β1 integrins. Consistent with these data, cell adhesion assay demonstrated that FliI knockdown cells were less adherent than wildtype cells. Our findings indicate that FliI may regulate cell migration by interacting with the actin monomers and the mitochondria to affect cell adhesion. flightless I cell migration actin cytoskeleton mitochondria cell adhesions 0567
4	Calcium/Calmodulin Dependent Protein Kinase Type-II Associates with Flightless-I to Influence its Nuclear Localization Seward, Matthew Edward 01 January 2006 (has links) Ca2+/calmodulin-dependent protein kinase type-II (CaMK-II) is a Ser/Thr protein kinase regulated by Ca2+ and Calmodulin. It is a highly conserved and broadly expressed enzyme and has a unique structure and dynamic regulation. It has the ability to remain active in the absence of Ca 2+ as a result of Ca2+ dependent autophosphorylation. CaMK-II phospliorylates proteins involved in neurotransmitter secretion, long term potentiation, cytoskeletal dynamics, gene transcription, and cell motility. To support existing and identify new intracellular roles of CaMK-II, potential binding partners were identified. This was accomplished by transfecting and purifying "FLAG-tagged" CaMK-II's (α, βE, δC, and δE). CaMK-II associated proteins were then identified using tandem mass spectrometry. Known binding partners were identified using this approach, including CaMK-II and calmodulin, verifying the approach's validity. Additionally several unexpected but interesting proteins were identified, including the gelsolin related actin binding protein, Flightless-I. Fli-I is an actin binding and capping protein that also functions as a transcriptional coactivator. The CaMK-II-Fli-I interaction was confirmed with endogenous (un-tagged) proteins. The association and localization of Fli-I are dependent on CaMK-II's activity state, although Fli-I is not a substrate of CaMK-II. When CaMK-II is inhibited, Fli-I translocates to the nucleus. Conversely when CaMK-II is artificially activated using a Ca2+ ionophore, Fli-I returns to the cytosol. The discovery of this reversible interaction epresents a potentially new CaMK-II regulated pathway and likely serves as a link between Ca2+ based signal transduction pathways and regulation of the actin component of the cytoskeleton and transcription. cytoskeleton Calmodulin signal transduction pathways Flightless-I CaMK-II Biology Life Sciences
5	Modeling Flightless Galapagos Seabirds as Impacted by El Nino and Climate Change Putman, Brian Seth 01 September 2014 (has links) Noteworthy species endemic to the Galapagos Islands off Ecuador are two flightless birds, the Galapagos Penguin (Spheniscus mendiculus) and Flightless Cormorant (Phalacrocrax harrisi). Both adapted increased swimming ability at the cost of flight. This however has limited their ability to find richer feeding grounds in times of low resource availability, or to escape potential predators. Their population numbers, though small, were stable. Stress on this stability has increased since human arrival. Various invasive species from pets, farm animals and rats to even mosquito vectors of avian disease accompanied humans. . El Nino Southern Oscillation or ENSO cycles of warm waters in the Pacific Ocean south of the Equator cause drastic drops in food sources for all Galapagos seabirds. Serious ENSO events in 1983 and 1998 caused some species’ populations to drop by as much as 77%. Periodic less severe cycles may help explain how population recovery has not rebounded to earlier numbers. Reduced chick survival and adult fecundity seem to occur in concert with mild events. With available data and use of a modeling approach, this study focuses and explores their situations. Restoring population stability may include use of models, species monitoring, conservation and limiting invasive species. Usher matrices based on different climate conditions were produced using data combined from current and past census counts and weather. Models are used to compare available census data and test reliable predictors. Climate data from National Oceanic and Atmospheric Administration and the University of Florida provides for testing predictions of current and probable future climate change. Life histories of both species are regarded. Results suggest the current Cormorant population is still stable. The Penguin, however, faces a 20% probability of extinction in 100 years if current conditions remain. Extinction probability rises to 60% if climate change continues to worsen. Interventions such as captive breeding could be suitable for population recovery. Spheniscus or Banded Penguins ENSO cycle Population modeling Leslie matrix Quasi extinction threshold Life Cycle Graph Marine Biology
6	Consequences of Insect Flight Loss for Molecular Evolutionary Rates and Diversification Mitterboeck, T. Fatima 25 May 2012 (has links) This thesis investigates the molecular evolutionary and macroevolutionary consequences of flight loss in insects. Chapter 2 tests the hypothesis that flightless groups have smaller effective population sizes than related flighted groups, expected to result in a consistent pattern of increased non-synonymous to synonymous ratios in flightless lineages due to the greater effect of genetic drift in smaller populations. Chapter 3 tests the hypothesis that reduced dispersal and species-level traits such as range size associated with flightlessness increase extinction rates, which over the long term will counteract increased speciation rates in flightless lineages, leading to lower net diversification. The wide-spread loss of flight in insects has led to increased molecular evolutionary rates and is associated with decreased long-term net diversification. I demonstrate that the fundamental trait of dispersal ability has shaped two forms of diversity—molecular and species—in the largest group of animals, and that microevolutionary and macroevolutionary patterns do not necessarily mirror each other. / Generously funded by NSERC with a Canada Graduate Scholarship and the Government of Ontario with an Ontario Graduate Scholarship to T. Fatima Mitterboeck; NSERC with a Discovery Grant to Dr. Sarah J. Adamowicz evolution flight transitions insects molecular rates diversification flightless flight loss dispersal holometabola insect species species richness effective population size population size population subdivision macroevolution microevolution comparative method substitution rates dN/dS ratios non-synonymous substitutions nearly neutral theory molecular clock mitochondrial DNA nuclear DNA OXPHOS COI COX1 Cytochrome c oxidase subunit I pterygota speciation extinction whole-tree method sister-group method

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