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Physiology and Biochemistry Graduate Seminar Series

This seminar series allows communication of proposed research or recent results to the P&B graduate group. Participation is compulsory for Physiology & Biochemistry students, and all members of the department are welcome as guests. The talks are held each Thursday at 12:30 on ZOOM.

Contact Jim Staples for further information.

April 8, 2021

Julia Hammer supervised by Dr. Danielle Way: "How will climate change affect the CO2 dynamics of Canada’s boreal forests?"

Abstract: Boreal forests are an important reservoir of terrestrial organic carbon and a key component of the global carbon cycle. Despite this, we have relatively few data on the physiological responses of boreal trees to climate change. My goal is to explore how foliar photosynthesis and respiration in Canadian boreal trees responds to sustained exposure to high temperature and high atmospheric CO2 levels. The results of my project will improve the accuracy of our Earth system models, provide insight on forest productivity in the future and further our understanding of thermal and CO2 acclimation in plants.

 

Tania Naseer supervised by Dr. Brent Sinclair: "Development of RNA Interference in Gryllus veletis"

 

Brynne Duffy supervised by Dr. James Staples: "Hibernation R&R: Reverse Electron Transport and Reactive Oxygen Species in the Thirteen-lined Ground Squirrel"

Abstract: During hibernation, thirteen-lined ground squirrels (TLGS) cycle between torpor and interbout-euthermia (IBE). Due to drastic changes in heart rate, each arousal has been considered similar to an ischemia-reperfusion event. However, TLGS survive dozens of arousals during a hibernation season suggesting resistance to changing oxygen availability and ROS. The nature of this resistance remains unclear. I hypothesize that suppression of mitochondrial metabolism during hibernation protects against oxidative damage. I measured ROS production following anoxia-reoxygenation of torpor and IBE isolated liver mitochondria. I predict lower ROS production during torpor, when metabolism is suppressed and increased ROS production in both IBE and torpor after anoxia-reoxygenation.

 

Spencer Matt supervised by Dr. Sheila Macfie: "Effects of sulfur on cadmium uptake and translocation in soybean (Glycine max)"

Join us for the final seminar session for this term ten minutes before the start of the talk (https://westernuniversity.zoom.us/j/93254662783).


Previous Seminars

March 25, 2021

Alyssa Stephens supervised by Dr. Brent Sinclair: "How does the freeze tolerant spring field cricket (Gryllus veletis) accumulate trehalose?"

Abstract: The spring-field cricket, Gryllus veletis, is freeze tolerant at the 5th instar when exposed to a 6-week cold acclimation of gradually decreasing temperature and photoperiod. During this acclimation, G. veletis accumulate low molecular weight cryoprotectants such as trehalose; however, the mechanism underlying trehalose accumulation is still unknown. The goal of my project is to determine if the trehalose pathway (production, transportation, and consumption) is modified during acclimation to facilitate trehalose accumulation. I will be showing preliminary data on trehalose production and mobilization.


March 18, 2021

Zhujun Qiu supervised by Dr. Frédéric Marsolais: "Evaluation of Bioactive Properties of Peptides Derived From Common Bean (Phaseolus vulgaris L.)"

Abstract: My project has focused on the properties of small bio-active peptides in cooked common bean (Phaseolus vulgaris L.) especially in antioxidant, anti-diabetic and antimicrobial ability. I hypothesised that small peptides (600-1000 Da) have effect for these abilities talked above. I have tested 4 genotypes of common bean for 2 different antioxidant experiments, an anti-diabetic experiment (Dipeptidyl peptidase-IV inhibition experiment) and 2 varieties of bacteria for antimicrobial experiment, found that they were all work for these abilities but significant different in varieties. The further step for my project is to identify these active compounds by LC-MS for anti-diabetic property and provide more data for later person who wants to continue this project.


March 11, 2021

Amalie Hutchinson supervised by Dr. James Staples: "Hibernation is super complex: electron transport system supercomplex formation"

Abstract: Thirteen-lined ground squirrels (TLGS) hibernate during winter months. Hibernation consists of two states: torpor (low metabolic rate (MR)) and interbout euthermia (IBE, high MR). Previous research in the lab has suggested that changes to the electron transport system (ETS) contribute to suppressing metabolism. Each ETS complex can form supercomplexes (SCs) within the inner mitochondrial membrane. SCs are thought to improve ETS efficiency, stability, and decrease ROS production. 2D blue-native SDS PAGE can reveal differences in SC abundance through densitometric analysis. Preliminary results show decreased SC abundance in torpor compared to IBE and summer in the heart and liver of TLGS.

Kevin Young supervised by Dr. Chris Guglielmo: "How do Arctic-breeding shorebirds manage rapid phenotypic transitions on a tight schedule?"

Abstract: Arctic-breeding shorebirds are under strict time constraints to commence breeding shortly after arriving to their potentially snow-covered breeding areas. The costs of delayed breeding may include nest failure or the unsuccessful migration of their offspring and ultimately reduced fitness. I aim to evaluate how migratory shorebirds manage their transitions between life-history stages and how a gradient of strategies influences adult and juvenile success. I will use a combination of techniques for studying whole-animal physiology, organ system function, transcriptional control, and space-based tracking in a wild population of migratory shorebirds in the Canadian high-Arctic.


March 4, 2021

Libesha Anparanasan supervised by Drs. Keith Hobson and Jeremy McNeil: "Allocation of larval and adult acquired essential and nonessential fatty acids to flight and reproduction in two adult Lepidoptera: Danaus plexippus and Mythimna unipuncta"

Abstract: Many insect species are migratory, but migration is energetically costly, leading to a trade-off between migration and subsequent reproduction. This trade-off can be managed by differentially allocating specific fatty acids to these life-history processes, thereby reducing overlapping nutritional requirements. How different ecological conditions experienced by individuals affect differential allocation has not been well explored. My goal is to evaluate source and allocation of fatty acids used during flight and egg investment in true armyworm moths and monarch butterflies. I will address allocations under fall and summer conditions in a laboratory setting using gas chromatography and stable isotopic analytical techniques.

Jessica Sinka supervised by Dr. Mark Bernards: "Metabolic Flux Analysis During Wound-Healing in Potato Tubers"

Abstract: In response to wounding, plants form a suberized wound periderm to protect exposed tissues from environmental threats. To monitor wound-induced suberization I am using carbon flux analysis, based on stable isotope labeling, to track metabolism leading to suberin deposition and associated secondary metabolic processes. This presentation will focus on my progress in quantification of labeled carbon found in metabolites downstream of the 13C-labeled D-Glucose, administered to wounded potato tubers, as a precursor. Select primary metabolites (e.g. phosphor-enol-pyruvate, pyruvate, shikimate, phenylalanine) will be used as proxies to measure flux through diverging metabolic pathways leading into the suberin macromolecule.


February 18, 2021

Soren Coulson supervised by Drs. Chris Guglielmo and Jim Staples: "Effects of prolonged flight on mitochondrial function in a migratory songbird"

Abstract: Birds continuously fly for several hours to days during migration. Reactive oxygen species (ROS) formed during flight may damage flight muscle mitochondria. I hypothesize that mitochondrial performance declines with flight. I tested this hypothesis using blackpoll warblers (Setophaga striata) in 3 flight conditions: 1) pre-flight, 2) post-flight and 3) fasted controls. I compared mitochondrial performance among flight conditions using high-resolution fluororespirometry on isolated flight muscle mitochondria to measure O2 consumption and ROS production rates while oxidizing different substrates. In contrast to my hypothesis, I found that substrate oxidation and ROS production are relatively unchanged with flight, indicating no mitochondrial damage

Paul Boersma supervised by Dr. Sheila Macfie: "Silver Nanoparticles: Friend or Foe and the Woe of Symbiosis"

Abstract: My project has focused on the effects of silver nanoparticles (AgNPs) on soybean (Glycine max) growth and symbiosis with Bradyrhizobium japonicum USDA 110. I have shown that AgNPs (30 ± 2.7 and 16 ± 2.5 nm) are taken up by the roots and translocated to shoots. I have also shown that the bacterial symbiont is negatively affected, both in and outside the nodule, and that nodule mass and overall nitrogen fixation decreased with increased AgNP concentrations. Plant growth was inhibited by AgNPs, due to both poor nodule health and other untested factors. Therefore, AgNPs are a contaminant of concern.


February 11, 2021

Andrew Rabas MSc candidate supervised by Dr. Mark Bernards: "Mitigating Ginseng Replant Disease with Soil Solarization"


February 4, 2021

Carlie Muir PhD candidate supervised by Drs. Sashko Damjanovski and Bryan Neff: "It’s getting hot in here: The effect of elevated rearing temperature on the cardiorespiratory physiology of Atlantic salmon"

January 28, 2021

Indira Queralta MSc candidate supervised by Dr. Mark Bernards: "Role of HXXXD-motif Acyltransferases in Suberin Biosynthesis"

Karina Kaberi  MSc candidate supervised by Dr. Mark Bernards: "The analysis of ginsenosides in ginseng garden soil)"


March 12, 2020

Kevin Young PhD candidate co-supervised by Dr. Chris Guglielmo and Dr. Vezinza: "Do declining fall temperatures restrict fuelling in a High Arctic migrant?"

Zhujun Qiu  MSc candidate co-supervised by Dr. Frédéric Marsolais and Dr. Robert Cumming: "Evaluation of Bioactive Properties of Peptides Derived From Common Bean (Phaseolus vulgaris L.)"

Jackie Lebenzon  PhD candidate supervised by Dr. Brent Sinclair: "A tale of two strategies: The physiological mechanisms underlying diapause and cold tolerance in the Colorado potato beetle"


March 5, 2020

Megan Lambert MSc candidate co-supervised by Dr. Mark Bernard and Dr. Greg Thorn: "Dynamics of the Soil Microbiome in Ginseng Gardens"

Sarah McDonald  MSc candidate supervised by Dr. Danielle Way: "Climate change effects on floral traits and carbon dynamics of cucumber: Potential consequences for a plant-pollinator mutualism"


February 27, 2020

Kurtis Turnbull PhD candidate co-supervised by Dr. Brent Sinclair and Dr. Jeremy McNeil: "Microhabitat selection and modification by a soil-dwelling insect prior to winter dormancy"

David Letwin  MSc candidate supervised by Dr. Vava Grbic: "Analysis of xenobiotic responses of Tetranychus urticae and Tetranychus evansi"


February 20, 2020

Alyssa Stephens MSc candidate supervised by Dr. Brent Sinclair: "How does Gryllus veletis accumulate trehalose?"

Libesha Anparasan  PhD candidate co-supervised by Dr. Keith Hobson and Dr. Jeremy McNeil: "Differential allocation patterns of essential and nonessential fatty acids between migration and reproduction in Lepidoptera"

Yanira Jiménez Padilla PhD candidate supervised by Dr. Brent Sinclair: “Species-specific effects of live yeasts on the chill coma recovery time of Drosophila melanogaster

Vinod Shankar PhD candidate co-supervised by Dr. Natasha Mhatre and Dr. Brent Sinclair: "Flux Analysis during Wound-Healing in a Potato Tuber"

Kumkum Azad MSc candidate supervised by Dr. Danielle Way: “Boreal tree responses to combined elevated CO2 and temperatures”


February 13, 2020

Soren Coulson PhD candidate co-supervised by Dr. Jim Staples and Dr. Chris Guglielmo: "Mitochondrial bioenergetics of migratory flight"

Paul Boersma  MSc candidate supervised by Dr. Sheila Macfie: "The Effects of Silver Nanoparticles on Soybean (Glycine max) Growth and Nodulation"

Jake Hauger PhD candidate supervised by Dr. Danielle Way: “Responses of Mature Boreal Forest Trees to Increased CO2 and Temperature in the Field”

Jessica Sinka MSc candidate supervised by Dr. Mark Bernards: "Flux Analysis during Wound-Healing in a Potato Tuber"

Amalie Hutchinson MSc candidate supervised by Dr. Jim Staples: “Hibernation is Super Complex: Electron Transport System Supercomplex Formation”


February 6, 2020

Josh Frank  PhD candidate co-supervised by Dr. Danielle Way and Dr. Tod Ramsfield: "Complex Effects of Root-Associated Fungi on Poplars Under Elevated Temperature and CO2".


January 30, 2020

Brynne Duffy  MSc candidate from Dr. Jim Staples' lab: "Acclimation capacity of photosynthesis and respiration to temperature and CO2 in dominant boreal tree species"

and

Bridget Murphy  MSc candidate from Danielle Way's lab: "Comparing the effects of extreme warming on tamarack under differing experimental designs"