Molecular analysis of placodal development in zebrafish

Vertebrates have evolved a unique way to sense their environment: placodallyderived sense organs. These sensory structures emerge from a crescent-shaped domain, the preplacodal domain, which surrounds the anterior neural plate and generates the paired sense organs as well as the cranial ganglia. For decades, embryologists have attempted to determine the tissue interactions required for induction of various placodal tissues. More recently, technological advances have allowed investigators to ask probing questions about the molecular nature of placodal development. In this dissertation I largely focus on development of the otic placode. I utilize loss-of-function techniques available in the zebrafish model system to demonstrate that two members of the fibroblast growth factors family of secreted ligands, Fgf3 and Fgf8, are redundantly required for otic placode induction. I go on to show that these factors are expressed in periotic tissues from the beginning of gastrulation. These findings are consistent with a model where Fgf3 and Fgf8 signal to preotic tissue to induce otic-specific gene expression. This model does not address other potential inducers in otic induction. A study using chick explant cultures suggests that a member of the Wnt family of secreted ligands also has a role in otic induction. I therefore test the relative roles of Wnt and Fgf in otic placode induction. The results demonstrate that Wnt functions primarily to correctly position the Fgf expression domain and that it is these Fgf factors which are directly received by future otic cells. Lastly, I examine the function of the muscle segment homeobox (msx) gene family expressed in the preplacodal domain. This study demonstrates that Msx proteins refine the boundary between the preplacodal domain and the neural plate. Further, msx genes function in the differentiation and survival of posterior placodal tissues (including the otic field), neural crest and dorsal neural cell types. Loss of Msx function results in precocious cell death and morphogenesis defects which may reflect perturbed BMP signaling

The influence of purposeful inferential questions on the comprehension outcomes of narrative reading at the intermediate level

The purpose of this study is to test whether purpose questions set on various aspects of excerpts from suitable children's literature and clarified in discussion will facilitate the improved inferential comprehension of intermediate level pupils. It was hypothesised in the influential nature of purpose in reading does operate and can be manipulated by the teacher, provided the purpose questions are understood by the reader and the material being read is not at 'frustration' level

Environmental Fate and Effects of Bacillus thuringiensis (Bt) Proteins from Transgenic Crops: a Review

This paper reviews the scientific literature addressing the environmental fate and nontarget effects of the Cry protein toxins from Bacillus thuringiensis (Bt), specifically resulting from their expression in transgenic crops. Published literature on analytical methodologies for the detection and quantification of the Cry proteins in environmental matrices is also reviewed, with discussion of the adequacy of the techniques for determining the persistence and mobility of the Bt proteins. In general, assessment of the nontarget effects of Bt protein toxins indicates that there is a low level of hazard to most groups of nontarget organisms, although some investigations are of limited ecological relevance. Some published reports on the persistence of the proteins in soil show short half-lives, whereas others show low-level residues lasting for many months. Improvements in analytical methods will allow a more complete understanding of the fate and significance of Bt proteins in the environment

Molecular analysis of placodal development in zebrafish

Vertebrates have evolved a unique way to sense their environment: placodallyderived sense organs. These sensory structures emerge from a crescent-shaped domain, the preplacodal domain, which surrounds the anterior neural plate and generates the paired sense organs as well as the cranial ganglia. For decades, embryologists have attempted to determine the tissue interactions required for induction of various placodal tissues. More recently, technological advances have allowed investigators to ask probing questions about the molecular nature of placodal development. In this dissertation I largely focus on development of the otic placode. I utilize loss-of-function techniques available in the zebrafish model system to demonstrate that two members of the fibroblast growth factors family of secreted ligands, Fgf3 and Fgf8, are redundantly required for otic placode induction. I go on to show that these factors are expressed in periotic tissues from the beginning of gastrulation. These findings are consistent with a model where Fgf3 and Fgf8 signal to preotic tissue to induce otic-specific gene expression. This model does not address other potential inducers in otic induction. A study using chick explant cultures suggests that a member of the Wnt family of secreted ligands also has a role in otic induction. I therefore test the relative roles of Wnt and Fgf in otic placode induction. The results demonstrate that Wnt functions primarily to correctly position the Fgf expression domain and that it is these Fgf factors which are directly received by future otic cells. Lastly, I examine the function of the muscle segment homeobox (msx) gene family expressed in the preplacodal domain. This study demonstrates that Msx proteins refine the boundary between the preplacodal domain and the neural plate. Further, msx genes function in the differentiation and survival of posterior placodal tissues (including the otic field), neural crest and dorsal neural cell types. Loss of Msx function results in precocious cell death and morphogenesis defects which may reflect perturbed BMP signaling

Putter Measurement System

This project is provided and funded by Callaway Golf Company for the Mechanical Engineering Department as a capstone project, also known as the Senior Project series: ME 428, 429, and 430. The title of the project proposal is Putter Measurement System in which our team must design, build, and test a system that meets the proposed objectives as stated by Callaway Golf. The need arises from the current systems’ inability to provide detailed and consistent measurements without tedious setup and calibration

Deletion of the hemopexin or heme oxygenase-2 gene aggravates brain injury following stroma-free hemoglobin-induced intracerebral hemorrhage

BACKGROUND: Following intracerebral hemorrhage (ICH), red blood cells release massive amounts of toxic heme that causes local brain injury. Hemopexin (Hpx) has the highest binding affinity to heme and participates in its transport, while heme oxygenase 2 (HO2) is the rate-limiting enzyme for the degradation of heme. Microglia are the resident macrophages in the brain; however, the significance and role of HO2 and Hpx on microglial clearance of the toxic heme (iron-protoporphyrin IX) after ICH still remain understudied. Accordingly, we postulated that global deletion of constitutive HO2 or Hpx would lead to worsening of ICH outcomes. METHODS: Intracerebral injection of stroma-free hemoglobin (SFHb) was used in our study to induce ICH. Hpx knockout (Hpx(−/−)) or HO2 knockout (HO2(−/−)) mice were injected with 10 μL of SFHb in the striatum. After injection, behavioral/functional tests were performed, along with anatomical analyses. Iron deposition and neuronal degeneration were depicted by Perls’ and Fluoro-Jade B staining, respectively. Immunohistochemistry with anti-ionized calcium-binding adapter protein 1 (Iba1) was used to estimate activated microglial cells around the injured site. RESULTS: This study shows that deleting Hpx or HO2 aggravated SFHb-induced brain injury. Compared to wild-type littermates, larger lesion volumes were observed in Hpx(−/−) and HO2(−/−) mice, which also bear more degenerating neurons in the peri-lesion area 24 h postinjection. Fewer Iba1-positive microglial cells were detected at the peri-lesion area in Hpx(−/−) and HO2(−/−) mice, interestingly, which is associated with markedly increased iron-positive microglial cells. Moreover, the Iba1-positive microglial cells increased from 24 to 72 h postinjection and were accompanied with improved neurologic deficits in Hpx(−/−) and HO2(−/−) mice. These results suggest that Iba1-positive microglial cells could engulf the extracellular SFHb and provide protective effects after ICH. We then treated cultured primary microglial cells with SFHb at low and high concentrations. The results show that microglial cells actively take up the extracellular SFHb. Of interest, we also found that iron overload in microglia significantly reduces the Iba1 expression level and resultantly inhibits microglial phagocytosis. CONCLUSIONS: This study suggests that microglial cells contribute to hemoglobin-heme clearance after ICH; however, the resultant iron overloads in microglia appear to decrease Iba1 expression and to further inhibit microglial phagocytosis

Production of biochemicals and biofuels with no CO2 production and improved product yields

Traditional fermentation processes for the production of the majority of biochemicals and biofuels produce CO2 because of decarboxylation reactions, which limits the final mass yields of products. To overcome this limitation, we have developed a fermentation technology called MixoFerm™ (also known as anaerobic, non-photosynthetic mixotrophy), which uses microorganisms capable of simultaneously consuming both organic (e.g., sugars) and inorganic (e.g., CO2, CO, or H2) substrates. With this technology, product mass yields for almost any biochemical or biofuel can be increased by at least 50%, and processes can be designed that result in no CO2 production. In order to achieve zero CO2 emissions for most products, exogenous reductant must be added to the system, since sugar lacks the necessary reducing energy to both fix CO2 and produce the product of interest. Here, we demonstrate concurrent consumption of both sugars and exogenously added reducing gases (CO and/or H2) to produce products of interest at enhanced mass yields and with no CO2 emissions. In addition, we have screened a library of acetogenic bacteria in order to find an optimal MixoFerm™ host strain, one that consumes both a broad range of carbohydrates and gases. From this library, we identified strains with a broader carbohydrate consumption range than traditional acetogens like C. ljungdahlii or C. autoethanogenum, and characterized their ability to grow under a variety of MixoFerm™ conditions to produce biochemicals at enhanced mass yields. With the ability to improve product yields for reduced products, especially for ethanol and other potential biofuels, MixoFerm™ is a robust and flexible platform technology to improve process economics and product life-cycle analysis

Extracorporeal life support in pediatric trauma: a systematic review

Introduction Extracorporeal membrane oxygenation (ECMO) was once thought to be contraindicated in trauma patients, however ECMO is now used in adult patients with post-traumatic acute respiratory distress syndrome (ARDS) and multisystem trauma. Despite acceptance as a therapy for the severely injured adult, there is a paucity of evidence supporting ECMO use in pediatric trauma patients. Methods An electronic literature search of PubMed, MEDLINE, and the Cochrane Database of Collected Reviews from 1972 to 2018 was performed. Included studies reported on ECMO use after trauma in patients ≤18 years of age and reported outcome data. The Institute of Health Economics quality appraisal tool for case series was used to assess study quality. Results From 745 studies, four met inclusion criteria, reporting on 58 pediatric trauma patients. The age range was <1–18 years. Overall study quality was poor with only a single article of adequate quality. Twenty-nine percent of patients were cannulated at adult centers, the remaining at pediatric centers. Ninety-one percent were cannulated for ARDS and the remaining for cardiovascular collapse. Overall 60% of patients survived and the survival rate ranged from 50% to 100%. Seventy-seven percent underwent venoarterial cannulation and the remaining underwent veno-venous cannulation. Conclusion ECMO may be a therapeutic option in critically ill pediatric trauma patients. Consideration should be made for the expansion of ECMO utilization in pediatric trauma patients including its application for pediatric patients at adult trauma centers with ECMO capabilities