Abstracts (11-20)

11) Gauri Chaggar, Microbiology/ Misha Miazga-Rodriguez & Lisa Stein, 398, Poster Presentation
Abstract Title: The diversity of a novel marker gene for methanotrophs, pxmA, in a methane biofilter system

Methane oxidizing bacteria (MOB) have been applied in methane biofilters (MBF) as a means to reduce the emission of methane biogas from municipal waste. Methane is a major greenhouse gas, over twenty times more potent than carbon dioxide in its global warming potential. MOB are able to utilize methane as a carbon and energy source. The apparent diversity of the MOB contained within the MBF will be surveyed through an examination of the diversity of the novel marker gene pxmA. A component of the pxmABC operon, the pxmA gene codes for a subunit of a theoretical methane monooxygenase enzyme. While the function of the pxmA gene is currently unknown, it has been found present in an assortment of MOB genera in pure culture. To aid in understanding the extent of diversity of this gene, degenerate polymerase chain reaction primer sets have been developed. These primer sets are being optimized for use on the MOB collected from the MBF. The use of clone libraries, restriction fragment length polymorphism (RFLP), and the consequent sequencing of clones, will assist in determining the diversity of the pxmA gene. Experimental research on this gene has been limited to only two publications and environments.

12) Julia Shonfield, Erin Bayne, PhD, poster
Abstract Title: Effects of Industrial Noise on Owls in Northeastern Alberta

Noisy environments can cause problems for animals that rely on vocal communication to defend territories and attract mates. Noise may also impact acoustic predators, such as owls, who use primarily acoustic cues made by prey when hunting at night. For species of owls living in the boreal forest of Northeastern Alberta, chronic noise from industry could reduce their ability to hear and be heard by other owls, as well as acoustic cues from their prey, which could impact their hunting efficiency. The overall goal of this project is to determine what effect industrial noise is having on owls in Northeastern Alberta. To detect owls I will use a new tool in species monitoring, automated recording devices, at noisy and quiet sites, and a combination of human-based and computer-based listening techniques. Part of this project will be looking more specifically at their hunting behaviour. Since small mammals make up the majority of the diet of owls, I am proposing to compare small mammal abundance and prey detection rates at noisy industrial sites and quiet sites. Some preliminary results from data collection in 2013 will be presented as well as future research plans.

13) Teaghan Mayers, Ecology/Case, M.Sc., oral presentation
Abstract Title: Microbial Turf Wars: Characterizing the defense of an algal host by a bacterial symbiont

Emiliania huxleyi is a globally abundant marine micro-alga that intermittently dominates huge tracts of open-ocean. Seasonal increases in light and nutrient availability are insufficient predictors of these blooms and the factors responsible for bloom initiation remain a mystery. This study aims to test the hypothesis that a known symbiont of E. huxleyi, P. gallaeciensis, confers protection against pathogens via the production of a potent antibiotic, tropodithietic acid. Rugeria sp. R11, a known bacterial pathogen of macroalgae, has been isolated from environmental samples of E. huxleyi. Preliminary experiments have shown that R11 is inhibited by P. gallaeciensis in biofilm assays and that R11 is pathogenic to E. huxleyi in co-culture. The protection of E. huxleyi from R11 by P. gallaeciensis is currently being investigated using one, two, and three species co-cultures. Bacterial populations are monitored using plate counts, while algal growth and photosynthetic health are measured using flow cytometry and pulse-amplitude modulated fluorometry. This research will provide insight into the dynamics of E. huxleyi’s symbiosis with P. gallaeciensis and could implicate this relationship in the initiation of E. huxleyi blooms if P. gallaeciensis is important in providing chemical defense against bacterial pathogens.

14) Jacob Gaster, Simon Landhäusser, M.Sc. in Land Reclamation and Remediation, both poster and oral presentation
Abstract Title: Carbon and nutrient dynamics underlying interactions between aspen (Populus tremuloides) and ectomycorrhizal fungi

Restoration of boreal forests is an important component of reclamation following oil sands mining.  In forest restoration, trees, soils and processes connecting them must be considered to create self-sustaining forest ecosystems. Ectomycorrhizal (ECM) fungi are organisms that colonize roots of most boreal tree species and functionally connect soils to host trees.  Trees exude carbon from their roots, which is absorbed by ECM fungi; in exchange, fungi assimilate nutrients from the soil, some of which are transferred to the tree.  This ecological ‘trade’ depends on the supply and demand of both carbon and inorganic nutrients between partners.  Supply and demand is likely modified by ECM fungal community composition, as species differ in carbon demand and nutrient uptake depending on their host species and soil environment.  My research will investigate how the carbon and nutrient status of the host affects ECM fungal species composition. To address this objective, I will compare ECM communities on trembling aspen (Populus tremuloides) seedlings, a widespread early successional species distributed across Canada and commonly used in reclamation, varying in tissue nutrient concentrations and grown in two different reclamation soils (forest floor material and peat mineral mix).

15) Julia Wong, Junshu Wang, Randi Guest Microbiology, Tracy Raivio, Ph.D., oral presentation
Abstract Title: Over-expression of nuoF, a component of NADH dehydrogenase I, inhibits the Cpx envelope stress response in Escherichia coli

Bacteria must sense environmental signals in order to adapt and survive. Two-component systems are the most abundant signal transduction proteins in nature but little is known about how sensor proteins sense signals. The Cpx two-component system senses protein misfolding in the Gram-negative envelope via the sensor kinase, CpxA. CpxA transduces the signal to the cytoplasmic response regulator, CpxR, which modulates the transcription of over 100 genes, including cpxP. CpxP inhibits Cpx activation but deletion of cpxP activates the pathway less than two-fold. We sought to find novel inhibitors of the Cpx pathway by over-expressing Cpx-regulated envelope-localized genes in a strain carrying a cpxP-lacZ transcriptional reporter and screening for white colonies on MacConkey agar. Over-expression of nuoF, the electron-binding component of NADH dehydrogenase I, inhibits Cpx activity in a CpxR-dependent manner. Similarly, deletion of nuoF results in two-fold activation of cpxP-lacZ activity. NuoF over-expression generates a novel, cytoplasmic signal sensed by the Cpx system.

16) Robert Patry, Microbiology and Biotechnology/Dr. Christine Szymanski, BIOL499 student, oral presentation
Abstract Title: Cholera toxin influence on Campylobacter jejuni

Campylobacter jejuni is the leading cause of bacterial diarrhea worldwide and infection can lead to the development of Guillain-Barré Syndrome. To avoid immune detection, the bacterium mimics human gangliosides with lipooligosaccharides (LOS) on its surface. In some cases, the host’s immune system sees the LOS structures as foreign and produces antibodies that cross-react with gangliosides present on nerve cells resulting in paralysis. Though C. jejuni has the ability to vary the LOS ganglioside mimics, there are no known selective pressures. Vibrio cholerae secretes cholera toxin (CT) which specifically binds to GM1 ganglioside structures on human cells and can bind to C. jejuni GM1 ganglioside-mimicking LOS. This project examines whether CT can influence C. jejuni LOS variation. Interestingly, experiments show that adding CT to C. jejuni strains expressing GM1-mimicking LOS results in bacterial clearing on agar, while spotting on other strains has no effect. The remaining bacteria were isolated from the clearance zones and compared to untreated bacteria by SDS-PAGE followed by silver staining and Western blotting. The results demonstrated that bacterial cells remaining after CT exposure were unable to bind CT suggesting that C. jejuni may phase vary its LOS structures in the gastrointestinal tract in the presence of CT.

17) Susan Anthony, Dr. A.R. Palmer, M.Sc., oral presentation
Abstract Title: The ultimate insult: nudibranch sequestration of cnidarian nematocysts

Aeolid nudibranchs, such as Hermissenda crassicornis, have a unique way of acquiring their defenses: they steal them from their prey. Whether these sea slugs steal different defenses in the presence of different predators remains an open question. Aeolids will feed on cnidarians (corals and anemones), digest their tissue, but store the cnidae – stinging capsules formed by cnidarians – in specialized sacs at the tips of their dorsal papillae (=cerata). The cerata will therefore have only the specific set of cnidae (of which there are more than 26) that are made by the food they are eating. Another aeolid is reported to switch food in the presence of different predators, presumably to gain the cnidae most useful to defense itself. To test whether this predator mediated prey selection is a feature of aeolids, I replicated the experiment with H. crassiocornis. I compared the cnidae complements (=cnidom) of slugs after exposure to different predators, and found that they did not differ between treatments. I also compared the cnidoms from H. crassicornis collected from different sites around Barkley Sound, BC and found significant differences in the cnidoms among sites, indicating that cnidoms are most likely the result of prey availability, and not predator pressure.

18) Kaitlyn Chow, Microbiology and Biotechnology, Supervisor: Camilla Nesbo, 499, poster
Abstract Title: Investigating biogeographical and evolutionary patterns in Petrotoga spp. using whole genome sequencing

Petrotoga is a genus of anaerobic thermophilic bacteria which to date have only been isolated from petroleum reservoirs, suggesting that they are indigenous. Due to the geographical and temporal separation of petroleum reservoirs, different strains are expected to exhibit genetic divergence consistent with the “island biogeography” model of evolution. We are investigating the evolutionary processes affecting Petrotoga by comparing the genome sequences of thirteen strains isolated world-wide: one isolate each from the Gulf of Mexico, Oklahoma—Texas, Congo, and the North Sea; three from Western Siberia; and six from Alberta. Pan-genome analysis and quartet decomposition indicate that the isolates cluster into four lineages: all Siberian isolates; four Albertan strains plus the North Sea isolate; the two other Albertan strains; and the remaining three strains, including the other North American isolates. Interestingly, the two Albertan isolates that form a lineage are highly divergent from the other strains (92-94% 16S rRNA identity between these two strains and the others, compared to >97% identity among the eleven other isolates). These preliminary results suggest that the physical distance between petroleum reservoirs does act, to some extent, as barrier to gene flow between populations, but geography alone cannot sufficiently explain the clustering patterns we observed

19) Sonya Widen, Molecular Biology and Genetics/Andrew Waskiewicz, MSc, oral presentation please! <widen@ualberta.ca>
Abstract Title: Sfrps modulate Wnt and BMP signaling during embryonic eye development

Sensory systems depend on precise axonal connections to neural processing centers. Axial patterning of neurons within the vertebrate retina establishes appropriate expression of guidance molecules to correctly connect the retina and brain. The dorsal retina is initially specified by the actions of Bone Morphogenetic Protein (BMP) signaling, with such identity subsequently maintained by Wnt signaling. A group of genes known as Secreted frizzled related proteins (sfrp) are known Wnt signaling modulators and have been shown to facilitate Wnt signaling in the developing mouse retina, therefore promoting dorsal retina identity.  Using zebrafish as a model system, we show that Sfrp1a and Sfrp5 work cooperatively to pattern the retina along the dorsal-ventral axis. We also show that Sfrp1a/5 depleted embryos display a reduction in dorsal marker gene expression and a corresponding reduction in BMP and Wnt signaling.  However, we note an unexpected increase in BMP ligand expression in Sfrp1a/5 depleted embryos, a phenotype expected only in embryos with inhibited BMP signaling. Additionally, overexpression of low doses of sfrp5 mRNA causes an increase in dorsal retina marker gene expression. These data implicate sfrps in regulation of ocular BMPs and show the very first evidence of Sfrp facilitation of BMP signaling.

20) Ido Hatam, Microbiology/Lanoil lab, PhD, Oral
Abstract Title: (Sea) Ice Ice Baby; implication of the shift to seasonal ice cover on the bacterial communities of the Arctic sea ice.

Bacterial communities in the Arctic sea ice play an important role in year-round regulation of nutrient and energy dynamics in the Arctic Ocean ecosystem.  These communities are exposed to strong top-to-bottom gradients in many key biotic and a-biotic factors. Furthermore, multiyear ice (MYI) has at least two distinct ice layers, old impermeable ice and new ice, and may also include a third layer of surface melt pond.  In this study, we test whether the structure of the communities varies with depth and whether these changes correspond with layer or gradient in environmental factors. We sampled ice cores from a multi-year floe, off the shore of Northern Ellesmere Island, NU, Canada and sub-sectioned them in 30 cm intervals. The bacterial community structure was characterized using pyrotag sequencing of the 16S rRNA gene.  Bacterial communities could be clustered into three distinct groups: top; middle; and bottom.  These layers correspond to the occurrence of melt pond refrozen ice, two-year old ice, and first-year ice layers, respectively.  These results imply that with the climate-change driven ongoing shift to a MYI-free Arctic Ocean, this ecosystem will lose two distinct bacterial communities, old and melt pond that are not present in seasonal sea ice.