Biology Seminar Series

 

Welcome to UTM Biology Seminar Series 2022-2023

 

When: Fridays, 12-1pm (unless otherwise indicated)

Where: DV2080 & Live Stream on Zoom (links are posted for each session)

 

Every Friday during the academic year, the Department of Biology hosts an exciting seminar given by a guest speaker. Topics cover every aspect of biology, from whole organisms to molecular biology. Everyone is welcome to attend.

December 2, 2022

http://www.shaunkillen.com/

Fuel and friends: Links between metabolism and social behaviours in fish

Individuals within species show tremendous variation in physiological and behavioural traits. Over the last decade there has been a surge of interest in the ecological and evolutionary importance of this diversity, but the vast majority of this work has been performed on isolated animals. In reality, however, most animals - from insects to mammals - do not live in a vacuum, but instead live within complex social structures. Social influences may override links between traits that exist in solitary animals. Conversely, an individual's standing within a group may be an important factor generating intraspecific variation. In this talk I will review some of our recent work examining the interplay between social behaviours and metabolic traits within various fish species and how such links may be modulated by environmental factors, and relevance for issues associated with fishing-induced selection.

We stream live here: https://utoronto.zoom.us/j/83721128905

November 25, 2022

How do co-circulating viruses interact within mosquitoes? 

West Nile virus is a flavivirus that is amplified in a "bird-Culex mosquito-bird" transmission cycle until it "spills over" into the mammalian population, generally late in the season. A model to predict when human cases of West Nile virus - based on 21 years of mosquito surveillance and viral testing data - will be presented. With global climate change, and the introduction of new mosquito vectors and new viruses, the possibility of more than one virus circulating in the environment increases. Information will be presented on what happens in cell culture and in live mosquitoes when more than one virus is present. The role of superinfection exclusion - when a non-pathogenic insect specific virus is present alongside a medically important virus such as West Nile virus, Zika virus or Mayaro virus - will be presented. 

 

Host: Dr. Rosalind Murray

November 18, 2022

https://tgelmi-candusso.github.io/

The spatial ecology of urban mammals in Toronto

Wildlife is a key part of the urban ecosystem, and while considered pests by many inhabitants, mesopredator mammals play an invaluable role in maintaining a healthy ecological dynamic. The effect of their presence can cascade across multiple trophic levels, as they control small mammal populations and disperse seeds. To better conserve them while managing the negative implications of their presence, we aim to understand how mammals navigate the city and how urban life may affect their species' interactions. In this seminar, we will illustrate how we have been studying urban wildlife in Toronto using both tracking data and camera traps. We will discuss our results on habitat selection, landscape connectivity, and net displacement of urban coyotes, the use of machine learning to accelerate camera trap data identification, and briefly describe the projects that have arisen from our camera trap data, which aim at better understanding mammal ecology in cities. 

We will live stream here: https://utoronto.zoom.us/j/89782522577

November 11, 2022

In Person
We live stream: https://utoronto.zoom.us/j/85766032761

  
Understanding the diurnal and seasonal dynamics of photosynthesis – from the molecular regulation of photosynthetic light conversion to the global carbon fluxes

u.rascher@fz-juelich.de     https://www.fz-juelich.de/en/ibg/ibg-2/forschung/research-groups/shoot-dynamics
Institute of Bio- and Geosciences, IBG-2: Plant Science, Forschungszentrum Jülich, Leo-Brandt-Str, 52425 Jülich, Germany
 
Plant photosynthesis is maybe one of the best understood biophysical and biochemical biological pathway, which combines photosynthetic light absorption, the usage of the energy in light reactions and the biochemical fixation of atmospheric CO2. Decades of basic and applied research have produced a good mechanistic understanding of the underlying mechanisms and their regulatory properties as well as a large amount of methods to non-invasively quantify the dynamics of photosynthesis. Fluorescence techniques are a widely used approach to directly quantify charge separation at photosystem II and to quantify the efficiency of photosynthetic light reactions non-invasively. Because of the rapid development of optical sensors and cameras, also fluorescence techniques have been greatly refined in the past years and nowadays fluorescence sensors can capture the fluorescence signal from larger distances enabling fluorescence measurements even from aircraft and satellite sensors.
In this seminar I will re-visit our current scientific understanding of the mechanistic link between the fluorescence signal and the functional properties of photosynthetic light reactions. I will give an update on the rapid development of new fluorescence measurement concepts, which include laser-induced fluorescence transients and the retrieval of solar-induced fluorescence from airborne and satellite plattforms. These novel data, which for the first allow to see and monitor the large scale dynamics of photosynthetic efficiency are exemplified with selected case studies, where we combined genetically modified plants with large scale, ecosystem modelling. Finally, I will briefly introduce the FLEX satellite mission concept (FLEX, FLuoresence EXplorer), which is currently implemented by the European Space Agency as Earth Explorer 8 and which will be launched in 2025. FLEX will have a spatial resolution of 300 meters and will provide global maps of solar-induced fluorescence and actual photosynthetic rates, which will allow for the first time to study the spatio-temporal dynamics of vegetation fluorescence and actual photosynthesis.
 
Selected recent publications
Mohammed G.H., Colombo R, Middleton E.M., Rascher U., van der Tol C., Nedbal L., Goulas Y., Pérez-Priego O., Damm A., Meroni M., Joiner J., Cogliati S., Verhoef W., Malenovský Z., Gastellu-Etchegorry J.-P., Miller J.R., Guanter L., Moreno J., Moya I., Berry J.A., Frankenberg C. & Zarco-Tejada P.J. (2019) Remote sensing of solar-induced chlorophyll fluorescence (SIF) in vegetation: 50 years of progress. Remote Sensing of Environment, 231, article no. 111177, doi: 10.1016/j.rse.2019.04.030.
Acebron K., Matsubara S., Jedmowski C., Emin D., Muller O. & Rascher U. (2021) Diurnal dynamics of non-photochemical quenching in Arabidopsis npq mutants assessed by solar-induced fluorescence and reflectance measurements in the field. New Phytologist, 229, 2104-2119, doi: 10.1111/nph.16984.
Porcar-Castell A., Malenovský Z., Magney T., Van Wittenberghe S., Fernández-Marín B., Maignan F., Zhang Y., Maseyk K., Atherton J., Albert L.P., Robson T.M., Zhao F., Garcia-Plazaola J.-I., Ensminger I., Rajewicz P.A., Grebe S., Tikkanen M., Kellner J.R., Ihalainen J.A., Rascher U. & Logan B. (2021) Chlorophyll a fluorescence illuminates a path connecting plant molecular biology to Earth-system science. Nature Plants, 7, 998-1009, doi: 10.1038/s41477-021-00980-4.

     
Host: Dr. Ingo Ensminger

November 4, 2022

Local adaptation at range edges and under anomalous climates

Species’ geographic ranges are limited on the landscape. A major focus of work in the Bontrager lab is identifying which evolutionary and ecological forces interact to shape species’ geographic distributions and limit adaptation. In addition, populations are frequently adapted to their local environments, and my lab works to identify which components of the environment are the most important factors driving local adaptation. To test the effects of gene flow at range edges, we deployed a large common garden experiment at the northern range edge of the wildflower Clarkia pulchella. Our results indicate that gene flow has generally positive effects at this edge and that these effects can be attributed to both heterosis and the movement of alleles from warm climates. We then conducted a quantitative synthesis of transplant experiments to 1) examine how climate change is altering patterns of local adaptation, 2) evaluate the relative importance of temperature and precipitation to local adaptation and 3) examine how the magnitude of local adaptation changes from range centres to range edges. We found that temperature adaptation is a major component of local adaptation, and that as little as two degrees of warming is adequate to disrupt patterns of local adaptation. This work confirms temperature as a critical driver of plant population performance and characterizes general patterns of adaptation across species' ranges. 

Host: Dr. Peter Kotanen

October 28, 2022

The roles of FACT during transcription elongation

Abstract:

In living cells, transcription occurs in the context of chromatin. During transcription elongation, RNA polymerase II therefore must negotiate with a series of nucleosomes that need to be disassembled in order for the polymerase to access the DNA template strand. Because nucleosomes are the hosts of epigenetic information (either as histone post-translational modifications or by the presence of histone variants), however, cells have evolved mechanisms to ensure their proper reassembly in the wake of transcription. Transcription is therefore coupled to a delicate balance of nucleosome disassembly and reassembly, a process that involves several chromatin regulators including histone chaperones FACT and Spt6. In this presentation, I will review our work on the role of FACT in preserving nucleosomes and their modifications, and propose a detailed mechanism for FACT recruitment to genes. I will also present data assessing the role of the high mobility group protein Nhp6 in FACT’s function.

Host: Dr. Ho-Sung Rhee

We stream live here: https://utoronto.zoom.us/j/86071064656

October 21, 2022

Title: Cracking the Olfactory Coding using Behavior

Abstract:

Two of the most fundamental questions of sensory neuroscience are: 1) how is stimulus information represented by neuronal activity? and 2) what features of this activity are read out to guide behavior? The first question has been the subject of a large body of work across different sensory modalities. The second question remains a significant challenge, since one needs to establish a causal link between neuronal activity and behavior.

In olfaction, it has been proposed that information about odors is encoded in spatial distribution of receptor activation and the next level mitral/tufted cells, as well as in their relative timing and synchrony. However, the role of different features of neural activity in guiding behavior remains unknown. Using mouse olfaction as a model system, we developed both technological and conceptual approaches to study sensory coding by perturbing neural activity at different levels of information processing during sensory driven behavioral tasks. We performed quantitative behavioral experiments to measure psychophysical limits of the readability of different features of the neural code, and quantify their behavioral relevance. Based on these results, we built a detailed mathematical model of the behavioral relevance of the different features of spatiotemporal neural activity. Our approach can be potentially generalized to other sensory systems.

Host: Dr. Arbora Resulaj

October 7, 2022

In Person POSTER

Algal viruses: friends or foes?

Marine viruses are now viewed as major drivers of biogeochemical cycles and as crucial components that shape microbial food webs. Our main understanding of these viruses stems predominantly from their study in marine habitats, where viruses are entangled in complicated but detrimental co-evolutionary arms race with their algal host. To that end, it is widely accepted that marine viruses can control the abundance of dominant microalgal communities, decide the faith of blooms, and affect the diversity of microorganisms in coastal and oceanic environments. Nevertheless, despite the ecological and societal importance of freshwater environments, our understanding of the role of viruses in freshwater habitats is at its infancy. In this talk I will first present an overview of some of the positive effects that virus infection of cosmopolitan marine microalga such as Emiliania huxleyi have. I will then ask the questions of whether virus infection in freshwater environments is as important as in marine systems, whether virus infection of toxic algae is contributing to the control of harmful algal blooms (HABs), or whether freshwater viruses actually contribute to worsening the effects of HABs.   

Host: Dr. Steven Short

September 30, 2022

In Person POSTER
Wildlife connectivity : teaming up with local people to enhance conservation
Maintaining connectivity among remaining habitat fragments is key to conserve biodiversity in a rapidly changing world. Effective landscape connectivity requires both a strong scientific basis to identify areas of conservation concern, and socio-political considerations to successfully protect these priority areas. I will present case studies from Panama, Australia, and Europe where efforts to maintain/restore connectivity for terrestrial mammals are currently being undertaken. After estimating functional connectivity for a suite of species using a combination of approaches (i.e., movement, occurrence, genetics), and identifying areas that would best facilitate species movement, I outline the different strategies that are being implemented together with local initiatives and Indigenous people to enhance the conservation of wildlife and their habitat

Host: Prof. Helene Wagner

September 23, 2022

September 16, 2022

Zoom POSTER
Advancing eDNA as a Tool for Exploration in Deepwater Environments
Environmental DNA (eDNA) sequencing and quantification complement established tools to assess the biodiversity of vulnerable benthic ecosystems. Offshore, marine eDNA may be transported long distances by complex ocean currents until it dilutes or degrades and is no longer detectable using PCR-based methods. A comprehensive understanding of the impact of marine physicochemical conditions on eDNA persistence has not been established. This gap in knowledge obscures the source location of eDNA from benthic ecosystems. In the mesophotic and deep ocean, below 30 meters depth, temperature, pH and dissolved oxygen concentration vary with depth and location. We conducted eDNA persistence experiments using eDNA derived from a deep-sea coral to determine the degradation rate among the natural combinations of temperature, pH and dissolved oxygen concentration that occur commonly in the deep ocean. The eDNA degradation process was best explained by a model with two phases with different decay rate constants. During the initial phase, eDNA degraded rapidly, and the rate was independent of physicochemical factors. During the second phase, eDNA degraded slowly, and the rate was strongly controlled by temperature and weakly controlled by pH. We did not find evidence that dissolved oxygen concentration from 0.1 mg/L to fully saturated conditions influenced eDNA degradation rate. Based on our results and publications using similar methods, we estimate that marine eDNA can persist at quantifiable concentrations for over 2 weeks at low temperatures (≤ 10 °C) but for a week or less at ≥ 20 °C. We propose a general temperature-dependent model to predict the maximum persistence time of eDNA detectable through single-species eDNA quantification methods. The relationship between temperature and eDNA persistence appears to be independent of the source taxa, however further experiments with other marine invertebrates are necessary. Community-wide sequencing data from eDNA samples at an offshore, mesophotic reef will test predictions regarding the transport extent of eDNA from benthic organisms and the application of eDNA analyses in these habitats. This research is supported by NOAA OER award NA18OAR0110289.

Host: Dr. Cassidy D'Aloia

In Person POSTER    RECORDING
Disease or NAT? RNA control of receptor expression
The LRR-RLK family of cell surface receptors is the largest group of receptor-like kinases in plants. They regulate plant growth, development, and stress responses including immune activation. To optimize these processes and overall plant fitness, their expression and activation are tightly controlled. As a result, many LRR-RLKs show tissue-specific, developmentally regulated, or stress-induced expression patterns. What remains unclear is how the plant achieves this level of expression specificity and inducibility to a wide-range of signals. Our work shows that the LRR-RLKs are significantly associated with regulatory non-coding RNA molecules. The expression of these regulatory RNAs is often tissue-specific and/or stress-induced, suggesting that their activity could explain the regulation of LRR-RLK expression in response to diverse cues. Using several examples, we demonstrate a variety of regulatory effects and mechanisms by which these RNAs control LRR-RLK expression in a tissue-dependent manner. This work provides a novel mechanism for regulation of a variety of plant growth and immune responses mediated by LRR-RLKs. 

Host: Dr. Marcus Dillon

September 9, 2022

Ahmed Hasan – In Person
Ph.D. Candidate, Dept. of Cell and Systems Biology
Ness Lab, aays.github.io
How and why does recombination rate vary?
Recombination rate varies at multiple scales across nature; between species, individuals, and across genomes. Here, I present some work on inferring variation in recombination rate and investigating its causes and consequences across the genome, as well as ongoing work to develop software for fast and efficient detection of recombination in bulk sequencing reads.
Dr. Rosemary Martin - Zoom
McCauley Lab
Hypoxia sensitivity and patterns of winterkill in larval anisopteran communities in temperate ecosystems
The depletion of dissolved oxygen in lakes and ponds as a result of extended ice coverage can lead to large die-offs of fish, a phenomenon known as winterkill. Hypoxic winter conditions act as an environmental filter and can shape fish communities in mid and high latitude ecosystems by selecting against hypoxia sensitive species. Most aquatic invertebrates remain active under ice, but it is generally unknown how periods of winter hypoxia affect activity levels and survival for many taxa. We surveyed larval dragonfly communities in 18 lakes in Michigan and Ontario for a total of 6 years of pre and post winter samples and identified dragonflies Anax junius and Leucorrhinia intacta as winterkill candidates. We experimentally tested relative sensitivity to low oxygen conditions in odonate species. Mortality of A. junius in hypoxic treatments was significantly higher compared with oxic treatments, but not for other dragonflies. Hypoxic conditions may contribute to patterns of overwinter declines in A. junius, a large bodied voracious top predator. Because of A. junius’s apparently higher sensitivity to hypoxia, habitats that become hypoxic in winter could be seasonal refuges from predation for aquatic organisms that are able to tolerate hypoxic conditions. Climate change is decreasing ice coverage duration which could decrease occurrences of hypoxia under ice. Reduced hypoxia could lead to greater numbers of A. junius present in spring communities and consequently increase predation pressure on aquatic invertebrates and other prey species.

2022-2023 Schedule

Date
 
Speaker
 
Title
 
Host
Sep 9. 2022
   
Ahmed Hasan

 
Dr. Rosemary Martin
 
How and why does recombination rate vary
 
Hypoxia sensitivity and patterns of winterkill in larval anisopteran communities in temperate ecosystems
 
 
Dr. Rob Ness
 
Dr. Shannon McCauley
 
Sep 16, 2022
 
Dr. Adam Mott
UTSC
   
Disease or NAT? RNA control of receptor expression
   
Dr. Marcus Dillon
Sep 23, 2022
 

Dr. Santiago Herrera
Lehigh University
 
Advancing eDNA as a Tool for Exploration in Deepwater Environments
 
Dr. Cassidy D'Aloia
Sep 30, 2022
 
Dr. Ninon Meyer, University of Newcastle
 
Wildlife connectivity : teaming up with local people to enhance conservation
 
Dr. Helene Wagner
Oct 7, 2022
 
Dr. Josef Nissimov, University of Waterloo
 
Algal viruses: friends or foes?
 
Dr. Steven Short
Oct 21, 2022
 
Dr. Dmitry Rinberg,
NYU Grossman School of Medicine
 
Cracking the Olfactory Coding using Behavior
 
Dr. Arbora Resulaj
Oct 28, 2022
 
Dr. Francois Robert,
      IRCM
 
The Roles of FACT during Transcription Elongation
 
Dr. Ho-Sung Rhee
Nov 4, 2022
 
Dr. Megan Bontrager, U of T
 
Local adaptation at range edges and under anomalous climates
 
Dr. Peter Kotanen
Nov 11, 2022
 
Dr. Uwe Rascher, Julich Research Center
 
Understanding the diurnal and seasonal dynamics of photosynthesis – from the molecular regulation of photosynthetic light conversion to the global carbon fluxes
 
Dr. Ingo Ensminger
Nov 18, 2022
 
Dr. Tziana Gelmi Candusso, U of T
 
The spatial ecology of urban mammals in Toronto
 
Dr. Christoph Richter
Nov 25, 2022
 
Dr. Fiona Hunter,
Brock University
 
How do co-circulating viruses interact within mosquitoes? 
 
Dr. Rosalind Murray
Dec 2, 2022
 
Dr. Shaun Killen, University of Glasgow
 
Fuel and friends: Links between metabolism and social behaviours in fish
 
EEB Grad Students
Dec 9, 2022
 
Dongyan Tan, Stony Brook University
 
Histone variants, the diverse building-block of chromatin in transcriptional regulation. Virtual
 
Dr. Mark Currie
Jan 13, 2023

 

Bridget Murphy
Madeleine Oman
 

Modelling the evolution and predictors of mutation rate variation
 
Dr. Ingo Ensminger
Dr. Rob Ness
Jan 20, 2023
 
Anja Groth, University of Copenhagen
 
 
 
CSB Grad Students
Jan 27, 2023
 
Dr. Lynn Adler, UMass Amherst
 
 
 
Dr. Marc Johnson
Feb 3, 2023
 
Dr. Douglas Allan, UBC
 
 
 
Dr. Ted Erclik
Feb 10, 2023
 
Dr. Amy Iler, Northwestern University
 
 
 
Dr. Marc Johnson
Feb 17, 2023
 
Dr. Michelle DiLeo, OMNRF
 
 
 
Dr. Helene Wagner
Mar 3, 2023
 
Dr. Jun Ding, Stanford University
 
 
 
Dr. Baohua Liu
Mar 10, 2023
 
Julia Zeitlinger, Stowers Institute for Medical Research
 
Deciphering the cis-regulatory code by interpretable deep learning
 
Dr. Ho-Sung Rhee
Mar 17, 2023
 
Dr. Ivana Cvijovic, Stanford University
 
 
 
Dr. Alex Nguyen Ba
Mar 24, 2023
 
Dr. Brady Johnson, University of Western Australia
 
 
 
BMC
Mar 31, 2023
 
Dr. Julia Stewart Lowndes
&
Ileana Fenwick
 
 
 
Grad Students
Milena Russo Design

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