Thesis (Ph.D.)--University of California, San Francisco, 2009. / Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 5933. Adviser: Wallace F. Marshall.

Thesis (M.S.)--University of California, San Francisco, 2009. / Source: Masters Abstracts International, Volume: 48-03, page: 1476. Adviser: Linda C. Giudice.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6187. Adviser: Abigail A. Salyers. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2006. / "Title from dissertation home page (viewed July 11, 2007)." Source: Dissertation Abstracts International, Volume: 67-08, Section: B, page: 4258. Adviser: Jeffrey D. Palmer.

Thesis (Ph.D.)--University of California, San Francisco, 2006. / Source: Dissertation Abstracts International, Volume: 67-08, Section: B, page: 4250. Adviser: Carol Gross. Includes bibliographical references. Also available online.

<p> Merosin deficient congenital muscular dystrophy type 1A (MDC1A) is caused by the loss of laminin-211 and laminin-221 heterotrimers which are most abundant in skeletal and cardiac muscle basal lamina; mutations in the LAMA2 gene cause the loss of these laminin isoforms. This absence of laminin-211/221 in MDC1A reduces the capacity for myofiber adhesion, loss of sarcolemmal integrity and subsequently the ability of the skeletal muscle syncytium to generate force in a coordinated and efficient manner. Patients experience progressive muscle wasting which confines them to a wheelchair at an early age and respiratory failure that leads to their untimely death. Currently, there is no effective treatment or cure for this devastating disease. Previous studies have shown that laminin-111, an embryonic form of laminin, delivered before disease onset can reduce muscle pathology and improve viability in the dyW-/- mouse model of MDC1A. These studies suggested that laminin-111 may act to strengthen and reinforce the sarcolemma and provide a protective niche for muscle repair. Since most patients are diagnosed with MDC1A after disease onset, we determined if laminin-111 could be beneficial after disease onset. Our studies suggest dyW-/- mice treated with laminin-111 after disease onset show improvement in muscle function and histology. Results from this study along with an understanding of laminin-111 pharmacokinetics will help pave the way in developing this protein as an exciting potential therapeutic for MDC1A patients. Duchenne Muscular Dystrophy (DMD) is the most common X-linked disease affecting 1 in 3,300 live male births. Patients with DMD suffer from severe, progressive muscle wasting and weakness with clinical symptoms first detected between 2 to 5 years of age; as the disease progresses patients are confined to a wheelchair in their teens and die in their early 20s mainly due to cardiopulmonary complications. DMD is caused by the loss of the sarcolemmal protein dystrophin (427kDa) due to mutations in the dystophin gene. When present, dystrophin acts as a scaffold linking the cell cytoskeleton to the extracellular matrix. This loss of dystrophin in DMD results in patients experiencing greater susceptibility to muscle damage via reduced structural and functional integrity of their muscle. One potential therapeutic avenue that needs to be explored involves increasing the levels of the ?7?1 integrin in order to compensate for the loss of dystrophin. To test this hypothesis, a muscle cell-based assay was developed in order to report ?7 integrin promoter activity with the intent of identifying molecules that promote ?7 integrin expression. Laminin-111 was identified as an enhancer of ?7 integrin expression. Theoretically, the identification of ?7 integrin enhancing compounds that help boost ?7?1 integrin expression as part of drug-based therapies may lead to a novel therapeutic approach for the treatment of this disease. Systemic laminin-111 treatment significantly reduces myofiber degeneration in both forms of MDC1A and DMD muscular dystrophy. This dissertation reinforces the potential of laminin-111 as a systemic protein therapy, capable of restoring sarcolemmal integrity thus reducing muscle disease progression. The importance of ?7 integrin in skeletal and cardiac muscle was highlighted here through the generation of the ?7-/-:: laminin-?2-/- double knockout mouse model. This mouse has never been studied before and could prove to be another important mouse model needed to explore therapeutic avenues for muscular dystrophy.</p>

<p> Coral reef ecosystems worldwide are facing increasing degradation due to disease, anthropogenic damage, and climate change, particularly in the Tropical Western Atlantic. Mesophotic coral ecosystems (MCEs) have been recently gaining attention through increased characterization as continuations of shallow reefs below traditional SCUBA depths (>30 m). As MCEs appear to be sheltered from many stressors affecting shallow reefs, MCEs may act as a coral refuge and provide larvae to nearby shallow reefs. The Deep Reef Refugia Hypothesis (DRRH) posits that shallow and mesophotic reefs may be genetically connected and that some coral species are equally compatible in both habitats. The research presented here addresses key questions that underlie this theory and advances our knowledge of coral connectivity and MCE ecology using the depth-generalist coral <i>Montastraea cavernosa</i>. Chapter 1 presents an overview of the DRRH, a description of MCEs in the Gulf of Mexico (GOM), and the framework of research questions within existing reef management infrastructure in the GOM. Through microsatellite genotyping, Chapter 2 identifies high connectivity among shallow and mesophotic reefs in the northwest GOM and evidence for relative isolation between depth zones in Belize and the southeast GOM. Historical migration and vertical connectivity models estimate Gulf-wide population panmixia. Chapter 3 focuses on population structure within the northwest GOM, identifying a lack of significant population structure. Dominant migration patterns estimate population panmixia, suggesting mesophotic populations currently considered for National Marine Sanctuary protection benefit the Flower Garden Banks. Chapter 4 quantifies the level of morphological variation between shallow and mesophotic <i>M. cavernosa</i>, revealing two distinct morphotypes possibly representing adaptive tradeoffs. Chapter 5 examines the transcriptomic mechanisms behind coral plasticity between depth zones, discovering a consistent response to mesophotic conditions across regions. Additionally, variable plasticity of mesophotic corals resulting from transplantation to shallow depths and potential differences in bleaching resilience between shallow and mesophotic corals are identified. The dissertation concludes with a synthesis of the results as they pertain to connectivity of shallow and mesophotic corals in the Gulf of Mexico and suggests future research that will aid in further understanding of MCE ecology and connectivity.</p><p>

<p> <i>Candida albicans</i> is a yeast-like fungal pathogen that can cause infections ranging from superficial to life-threatening systemic candidiasis. Current treatments for systemic candidiasis are available but often ineffective and toxic. Consequently, it is necessary to develop new therapeutic approaches. The purpose of this study was to construct antibody-based fusion proteins that can bind to <i>C. albicans</i> cells and eliminate them. Two such fusion proteins were constructed. Each one is composed of M1 Fab as the antibody component that binds to <i> C. albicans</i> mannan and the antifungal peptide HPRP-A1. HPRP-A1 was attached via a 15-amino acid linker to either the C-terminus of the constant light chain of M1 Fab (M1 Fab-HPRP-CL) or the N-terminus of the variable light chain of M1 Fab (M1 Fab-HPRP-VL). Binding of the fusion proteins to purified <i> C. albicans</i> mannan was assessed with enzyme-linked immunosorbent assay and the half maximal effective concentration (EC₅₀) for each fusion protein was estimated. EC₅₀ for M1 Fab-HPRP-CL was 273.6 compared to 74.1 for the original M1 Fab (<i>p</i> &lt; 0.05), whereas M1 Fab-HPRP-VL did not show any binding activity, indicating a negative impact on the antibody binding by the linked peptide. Similarly, M1 Fab-HPRP-CL also showed reduced binding for <i>C. albicans</i> cells when compared to M1 Fab as determined with immunofluorescence microscopy and flow cytometry. The effect of M1 Fab-HPRP-CL on the growth of <i>C. albicans</i> cells was analysed using microdilution and absorbance. At 16 &micro;M, the growth of yeast cells treated with M1 Fab-HPRP-CL was 47.1 % of the growth control, compared to 43.5 % for M1 Fab (<i>p</i> > 0.05) and to 1.9 % for HPRP-A1 by itself (<i>p</i> &lt; 0.001). Moreover, HPRP-A1 killed <i>C. albicans</i> at 32 &micro;M and 64 &micro;M, while M1 Fab and M1 Fab-HPRP-CL did not, indicating a loss of the antifungal activity of HPRP-A1 when attached to the antibody. These data together provide valuable insights into the development of novel antibody-based therapeutics as an alternative treatment for candidiasis.</p><p>

<p> Rod and cone photoreceptors in the retina are polarized sensory neurons that possess uniquely modified primary cilium, called the outer segment, to capture photons. Circadian-mediated shedding and renewal of outer segment membrane discs requires extensive vesicular transport of protein cargo from the endoplasmic reticulum and Golgi to the base of the cilium. Endocytosis is vesicle transport process of capturing and/or recycling extrinsic components and is shown to occur in retina of early vertebrates, such as <i>Xenopus</i> laevis. In this thesis, I have explored the hypothesis that a critical endocytosis-associated protein Rabgef1 is critical for the genesis of photoreceptor outer segments in the mammalian retina. After demonstrating high expression of Rabgef1 concordant with photoreceptor maturation, I characterized morphology and function of retina from <i>Rabgef1</i>-loss of function (<i>Rabgef1</i>^{&ndash;/&ndash;}) mice. Though no gross defect was observed by histology and immunohistochemistry before eye opening (postnatal day 14), transmission electron microscopy demonstrated ultrastructural defects in photoreceptor outer segments by P8. Progressive, yet rapid, photoreceptor degeneration and near-complete ablation of the visual response were evident at and after P15. I show that the outer segment defect noted in <i>Rabgef1</i>^{&ndash;/&ndash;} mice was not due to defective ciliogenesis or trafficking of cargo proteins to the cilium. In concordance with other systems, Rabgef1 was enriched in purified endocytic vesicles from the retina and interacted with Rabaptin5, confirming its role in Rab5-mediated endocytosis. Curiously, <i>Rabgef1</i>^{&ndash;/&ndash;} photoreceptors accumulated enlarged vesicular/endosomal structures within the inner segment, similar to loss of function mutations in the yeast orthologue of Rabgef1, Vps9p. My studies provide the first evidence of an essential role of Rabgef1-mediated fusion and recycling of endocytic vesicles in the formation and/or renewal of outer segment membrane discs in the mammalian retina. Rabgef1 and other components of the endocytic pathway should therefore be considered as candidates for human retinopathies. </p><p>

<p> Many adult stem cells are characterized by prolonged quiescence, promoted by cues from their niche. Upon tissue damage, a coordinated transition to the activated state is necessary for successful repair. Non-physiological breaks in quiescence often lead to stem cell depletion and impaired tissue restoration. Here, I identify cadherin-mediated adhesion and signaling between muscle stem cells (satellite cells; SCs) and their myofiber niche as a mechanism that orchestrates the quiescence-to-activation transition. Conditional removal of N-cadherin and M-cadherin in mice leads to a break in SC quiescence with long-term expansion of a regeneration-proficient SC pool. These SCs have an incomplete disruption of the myofiber-SC adhesive junction, and maintain niche residence and cell polarity, yet show properties of SCs in a state of transition from quiescence towards full activation. Among these properties is nuclear localization of b- catenin, which is necessary for this phenotype. These findings are consistent with the conclusion that injury-induced perturbation of niche adhesive junctions is a first step in the quiescence-to-activation transition. </p><p>