71) Michelle Campbell, Michael Caldwell, PhD, poster
Abstract Title: Expanding the speciocity and temporal range of the pythonomorpha- A new taxon from the Turonian of Croatia
In the summer of 2008, a new marine squamate was discovered on the island of Dugi Otok, Croatia (Turonian; U. Cretaceous). Though heavily weathered, the specimen is a well-articulated representative of a group of marine lizards previously thought to have gone extinct in the U. Cenomanian. The fossil consists of a worn impression and a few remaining bones. The lasting elements include the majority of the cervical and dorsal vertebrae, fragments of the ribs, and an exquisitely preserved left forelimb. Impressions from the cervical and most of the dorsal ribs are present, as is the impression of the pectoral girdle. The cranium, the tail, and the hind limbs have been lost. Its distinctively long, cylindrical body has at least 8 cervical vertebrae and ~23 preserved dorsal vertebrae with posteriorly curved ribs. Unfortunately, due to the missing pelvis, the exact dorsal count cannot be absolutely established, though it would be greater than 23. These features are consistent with other long-bodied pythonomorphs, and the long neck (> 7 cervical vertebrae) implies the consideration of this animal within the family Dolichosauridae. The vertebral count and unique features of the paddle-like forelimb and broad, flattened manus suggests that a new genus is represented.
62) Patricia Leighton- Physiology, Cell, and Developmental Biology RIG- supervisor Dr. W. Ted Allison- Ph.D. program- poster presentation
Abstract Title: Uncovering the normal functions of Alzheimer Disease associated genes using targetted zebrafish mutants
While much study has focused on contributions of amyloid precursor protein (APP) and prion protein (PrP) to Alzheimer and prion diseases, the normal functions of these proteins remain elusive. Zebrafish have two copies of APP (Appa and Appb) and PrP (Prp1 and Prp2) that share conserved functions with their mammalian homologs. We found a genetic interaction between Appa and Prp1 (Kaiser et al., 2012). We created a zebrafish Prp2 mutant using zinc finger nucleases (Fleisch et al., 2013), and we are working to engineer Prp1 and Appa mutants. We are using behavioural assays and immediate early genes to assess how these gene products interact to influence neuronal activity and synapse development.
We explored phenotypes in our Prp2 mutants using novel imaging techniques, behavioural assays, and in situ hybridization. We were unable to detect an overt phenotype in these mutants, but they were more susceptible to a convulsant as evidenced by a larger behavioural response and increase in c-fos expression. The latter is our earliest detected phenotype, which we are attempting to rescue with mRNA delivery.
Zebrafish Prp2 confers protection against neuronal hyper-excitability. These results are a promising step towards understanding PrP’s role in Alzheimer disease and will facilitate drug development.
63) Catherine Tays, Microbiology/Lisa Stein, M.Sc., poster
Abstract Title: Optimization of biopolymer production by microorganisms using single carbon substrates
Under certain conditions, methylotrophs are known to produce polyhydroxybutyrate (PHB), a precursor to next generation bioplastics, from single carbon (C1) compounds such as methane. Our partner company, TerraVerdae Bioworks, seeks to implement this biotechnology, using offgas streams and waste-derived C1 products to feed methylotrophs in bioreactors, producing bioplastics. This project is aimed at optimizing methylotrophic PHB production, examining the cellular regulation and pathways involved in its production and the development of processing strategies to optimize it. Global gene expression, bacterial growth, and PHB production will be assessed to characterize the molecular regulation and triggers for methylotrophic PHB biosynthesis. Bioreactor strategies (e.g. control strategies for the manipulation of growth conditions) will also be developed, taking into account optimal bacterial growth and PHB production, vital to achieving optimal PHB bio-production in an economically viable process. This integrated approach of microbiology and chemical engineering will create an optimized and well-characterized system of fermentation to obtain value-added products from an inexpensive greenhouse gas commonly released as by-product or waste from other industrial processes. Proper execution of this technology, supported by the data generated from this research, could result in production of materials that are useful to society, profitable, and non-harmful to the environment.
64) Phil Oel, Physiol/Cell/Devo Biology/ M.Sc/ poster
Abstract Title: Gdf6a has a role in determining photoreceptor subtype differentiation during retinal development
Responsible for vision, the retina is a thin, complex layer of neural tissue that has long been under intense physiological and medical scrutiny. The functions of the light-sensing photoreceptor cells have been well characterized, but an understanding of their development is still sorely lacking. We know of several genes with roles in photoreceptor development and maturation, but few are known to actually specify photoreceptor subtypes, as this research has historically been performed in the cone impoverished nocturnal mouse. Here, we discuss a new fate-regulating role for a protein with previously known functions in early eye development as well as in disease: zebrafish gdf6a, for which recent work has also shown roles in neurodegenerative and blinding disorders. The present study links gdf6a to photoreceptor development in three ways: gdf6a positively regulates tbx2b during relevant developmental time points; despite failing to elicit a characteristic tbx2b phenotype on its own, gdf6a influences the presentation of that phenotype when tbx2b mutation co-occurs; and finally, gdf6a mutation causes a unique photoreceptor abundance deficit among one subtype of cone photoreceptor. Thus, we have improved our understanding of photoreceptor development, and excitingly, enhanced the possibilities of our complementary project investigating mechanisms of retinal regeneration in zebrafish.
65) Elizabeth Mahon, Janice Cook, 499, poster
Abstract Title: Gene Expression Profiling and Population Genetics Analyses of Chitinase Genes in Jack Pine and Lodgepole Pine Inoculated with the Mountain Pine Beetle Fungal Associate Grosmannia clavigera.
The current mountain pine beetle (MPB, Dendroctonus ponderosae) outbreak is estimated to have affected ca. 19 million ha of Canadian forests to date (Arango-Velez et al in press). MPB has now spread beyond its historic range habitat moving northwards and eastwards, and shifting from lodgepole pine (Pinus contorta) into jack pine (Pinus banksiana) of northern Alberta (Cullingham et al 2011). There is ecological evidence that host trees originating from MPB’s historic range in central British-Columbia have lower host susceptibility than host trees from novel habits (Cudmore et al 2010, Raffa et al 2013). In addition, increasing global temperatures are predicted to result in longer, more frequent droughts for western Canadian forests, compromising tree defensive responses (Lusebrink et al 2011). In this project I am using qRT-PCR to identify differentially expressed chitinase genes in both well-watered and drought stressed lodgepole and jack pine seedlings inoculated with the MPB fungal associate, Grosmannia clavigera. I am also identifying single nucleotide polymorphisms, insertions, and deletions within these chitinases, and will use these as markers in population genetics studies elucidating differences between tree host populations. My expression analysis shows an attenuated response in chitinase expression from both jack and lodgepole pine when under drought conditions.
66) Joshua G. Pemberton, Ph.D., Poster Presentation
Abstract Title: Temporal aspects of signal transduction: long-term vs. short-term actions of GnRH in the control of pituitary cell function
Previous studies have shown that Class I phosphoinositide 3-kinases (PI3K) are involved in acute GnRH-2 (chicken (c)GnRH-II)- and GnRH-3 (salmon (s)GnRH)-stimulated GH and LH release from perifused goldfish pituitary cells. In this study, we examined the effects of the selective PI3K inhibitor LY294002 on basal and GnRH-induced GH and LH release as well as total hormone availability (sum of the secreted hormone and the cellular hormone content) in 2, 6, 12, and 24 h static incubation studies using primary cultures of dispersed goldfish pituitary cells. Results indicate that PI3K signal transduction differentially modulates basal and GnRH-stimulated hormone release in a time-, cell-type-, and GnRH isoform-selective manner. Interestingly, basal and agonist-induced changes in total hormone availability are dissociated from mRNA expression, in general.
67) Joshua G. Pemberton, John P. Chang/Physiology, Cell & Developmental Biology, Ph.D., Oral Presentation
Abstract Title: Understanding agonist-selective signal transduction mechanisms: differential signalling by two endogenous GnRH isoforms in goldfish, Carassius auratus.
Among its many functions, gonadotropin-releasing hormone (GnRH) stimulates luteinizing hormone (LH) and growth hormone (GH) release through direct actions on specialized pituitary cells called gonadotropes (LH-expressing cells) and somatotropes (GH-expressing cells). The presence of multiple GnRH isoforms in the brain, as well as in peripheral tissues, is a common feature among chordates and results from the goldfish (Carassius auratus) neuroendocrine model have revealed important cell-type- as well as GnRH isoform-selective signal transduction mechanims. In particular, goldfish pituitary cells are exposed to two native GnRHs, GnRH-2 ([His5, Trp7, Tyr8]GnRH) and GnRH-3 ([Trp7, Leu8]GnRH), and both GnRHs bind and activate the same population of cell-surface G protein-coupled receptors (GnRHR). Our ongoing research examines how the intracellular complexity of signal transduction systems participates in the hormonal control of growth and reproduction by modulating gonadotrope a!
nd somatotrope functions. Furthermore, by using a basal vertebrate model to contrast the cellular activities of unique molecular GnRH forms from teleost fish to mammals, our research also helps to elucidate how functional selectivity in hormone-receptor signal transduction systems has evolved and how this phenomenon can impact the physiology of the whole organism.
68) Hallie Street, Ecology and Evolution/Dr. Caldwell, Ph.D., poster
Abstract Title: Mosasaurus lemonnieri Dollo, 1889: A distinct and diagnosable taxon of mosasaurine mosasaur
Mosasaurus lemonnieri, has recently been suggested to be a junior synonym of Mosasaurus hoffmannii, on the basis that M. lemonnieri individuals are juveniles of M. hoffmannii. M. lemonnieri is currently recognized from specimens that are older than M. hoffmannii. However, several specimens of M. lemonnieri together with the M. hoffmannii holotype have been used to form the proposed growth series. To assess the strength of this hypothesis requires a rediagnosis of the type material of M. hoffmannii, and assessment of M. lemonnieri and the materials assigned to that taxon. We present the preliminary results of our investigation into the morphology, focusing on overall size, characters of the teeth, and quadrates. M. lemonnieri is smaller than M. hoffmannii; while there is evidence that M. lemonnieri is assignable to Mosasaurus, sharing characters including a dorsally convex maxilla and a nearly quadrilateral quadrate with a short suprastapedial process, there is also evidence to indicate that M. lemonnieri is not a junior synonym of M. hoffmannii. The teeth differ in morphology and number in the two species, and the dentary of M. lemonnieri tapers and extends anteriorly to the first tooth unlike M. hoffmannii. The morphology of these two species supports their continued separation.
69) Wael Elhenawy, Microbiology/biotech.,Feldman MF,PhD,Poster
Abstract Title: Preferential packing of acidic glycosidases and proteases into Bacteroides outer membrane vesicles
Outer membrane vesicles (OMV) are spherical membranous structures released from the outer membrane (OM) of gram negative bacteria. OMV have been proposed to play several different roles during both, pathogenesis and symbiosis. Whether OMV are produced by an active mechanism or by passive disintegration of the OM is a still matter of controversy. Bacteroides fragilis and B. thetaiotaomicron are important members of the human microbiota. In this work, we determined and compared the protein composition of OM and OMV from B. fragilis and B. thetaiotaomicron. SDS-PAGE analysis of both fractions revealed dramatically different protein profiles. Proteomic analysis of OM and OMV in B. fragilis identified more than forty proteins found exclusively in OMV, and more than 30 proteins detectable only in the OM. The OMV-specific proteomes showed a high prevalence of glycosidases and proteases, some of which were shown to be active in vitro. Similar results were obtained for B. thetaiotaomicron. Most of the OMV-exclusive proteins were acidic. Based on these results, we propose that these species posses a machinery devoted to selectively pack acidic proteins into the OMV. These OMV equipped with hydrolytic enzymes could help in securing nutrients for the benefit of the whole bacterial community present in the microbiota, uncovering a novel function for bacterial OMV.
70) Fatima Kamal, Molecular Biology and Genetics/ Dr. Jonathan Dennis, Ph.D, oral presentation
Abstract Title: Burkholderia cepacia complex Phage-Antibiotic Synergy (PAS)
The Burkholderia cepacia complex (BCC) is a group of 18 species of Gram-negative opportunistic pathogens that can cause chronic lung infection in cystic fibrosis (CF) patients. Since BCC bacteria have very high innate antimicrobial resistance, phage therapy is a proposed alternative treatment. Recently, some phages have been observed to show an effect named Phage-Antibiotic Synergy (PAS) wherein phages form larger plaques in the presence of sub-lethal concentrations of certain antibiotics. These reports suggest that certain antibiotics stimulate some bacteria to produce increased number of phages under certain conditions. The aim of this study is to examine PAS in phages that infect Burkolderia cenocepacia strains- C6433 and K56-2. BCC phages KS12 and KS14 were tested for PAS on the two strains respectively. Of the antibiotics tested, the most pronounced PAS effect was observed for meropenem, ciprofloxacin, and tetracycline. Plaque sizes and the corresponding phage titers both show increase with higher antibiotic concentrations. Cells show increased killing with time when treated with phage and antibiotics. The electron micrographs of B. cenocepacia cells show cells to be elongated in the presence of ciprofloxacin, as chains in the presence of meropenem and in groups in the presence of tetracycline. Tetracycline resistant K56-2 cells also demonstrate PAS shown by increased plaque size of KS12 on the mutant hosts in the presence of sub-inhibitory concentration of antibiotics. K56-2-infected G. mellonella larvae demonstrate increased survival when treated with phage KS12 and sub-lethal levels of meropenem over controls without meropenem. These results suggest that BCC phage therapy can be combined with low doses of antibiotics to improve efficacy.