Biology Seminar Series

PI: Prof. Adriano Senatore

Title: Evolution of iGluR ligand specificity, polyamine regulation, and ion selectivity inferred from a placozoan Epsilon receptor

Abstract: Epsilon ionotropic glutamate receptors (iGluRs) form a distinct sub-family among metazoan receptors, separate from AMPA, Kainate, Delta, and Phi (AKDF), NMDA, and Lambda sub-families. In this study, we investigated the evolutionary and functional characteristics of Epsilon receptors using homologues from the basal invertebrate Trichoplax adhaerens (phylum Placozoa). We constructed a new phylogeny of eukaryotic iGluRs guided by species and a comprehensive phylogeny of placozoan receptors, revealing significant diversification of Epsilon receptors into three conserved subclades, alongside four invariant subclades of AKDF receptors. Functional analysis of the T. adhaerens Epsilon receptor GluE1αA showed strong activation by glycine, alanine, serine, and valine, but not by glutamate. Using structural modeling and mutation experiments, we tested the hypothesis that specific amino acids in the ligand binding domain dictate ligand selectivity. By mutating three amino acids, we altered GluE1αA's selectivity towards glutamate, rendering it sensitive to AMPA and increasing susceptibility to the AMPA/Kainate receptor blocker CNQX. Furthermore, our combined modeling and mutation experiments identified a serine residue in the pore NQR site of GluE1αA, along with a downstream aspartate, as crucial for sensitivity to voltage-dependent polyamine block. This serine residue contrasts with the asparagine and glutamine residues found in AMPA and Kainate receptors, by diminishing both polyamine block and calcium permeation. In summary, our findings highlight conserved molecular determinants regulating polyamine sensitivity between Epsilon and AKDF receptors. Natural variations in NQR residues play significant roles in ion permeation and polyamine regulation, underscoring their importance in receptor function and evolution.

PI: Prof. John Ratcliffe & Prof. Darryl Gwynne

Title: Traffic Noise as a Source of Acoustic Interference in Crickets

Abstract: Female crickets reared in traffic noise have been reported to be faster or slower to locate male song than those reared in silence across species. We reared female Teleogryllus oceanicus in traffic noise and silence, and had adult females locate male song broadcast amidst traffic noise or silence. We recorded activity of two auditory interneurons in a subset of individuals under identical acoustic conditions. Regardless of rearing treatment, crickets were slower to leave their shelter when presented with male song in silence than in traffic noise, while crickets reared in traffic noise were also slower to leave overall. Crickets reared in traffic noise also had higher baseline AN2 activity, but rearing condition did not affect hearing thresholds or auditory response to male song. Our results demonstrate behavioural and auditory effects of long-term exposure to anthropogenic noise. Further, they support the idea that silence itself is a potentially aversive acoustic condition.

Hosted by: Prof. Adriano Senatore

Title: The neuron-free guide to nervous system evolution

Abstract: Neurotransmitters are chemical messengers that facilitate communication between neurons, allowing for the coordination of bodily functions and behaviour. Exploring their evolution helps us uncover the origins of neurons and nervous systems, revealing how they emerged and adapted in early life forms. By examining neurotransmitter systems across diverse species, we can trace the evolutionary steps that eventually led to the development of complex nervous systems. This research provides crucial insights into the foundational mechanisms of neural communication and deepens our understanding of the origins of brain function and behaviour in advanced organisms.

Hosted by: Prof. Ted Erclik

Title: Deterministic and stochastic neural fate determination in the Drosophila Visual System

Research Background: Dr. Desplan has been a Silver Professor at NYU since 1999 where he researches the development and function of the visual system in fruit flies (Drosophila), focusing on color vision. He studied calcium regulation for his Ph.D. at INSERM in Paris and worked on homeodomain proteins as a postdoc at UCSF. At Rockefeller University, he explored the structural and functional aspects of DNA binding domains and insect axis formation. His lab has revealed molecular mechanisms behind the patterning of color-sensing neurons and how color information is processed in the brain, utilizing neural stem cell lineage and patterning genes. Desplan also investigates evolutionary developmental biology using wasps and ants.

Desplan Lab Website: Desplan Lab – NYU Department of Biology

Hosted by: Prof. Ingo Ensminger

Title: Plant Optics: Bridging plant physiology and remote sensing for phenotyping applications

Abstract: Leaf optics is linked to plant physiology and structure. Because of this relationship, we can leverage remote sensing of leaf optical variation to estimate and assess plant traits and functions.  This talk will highlight examples of applications leveraging remote sensing of leaf optics for assessing plant responses across seasons and stress for phenotyping applications.

** Dr. Wong obtained his PhD from UofT where he was part of the Ensminger Lab! He successfully defended his thesis in 2020.

Research Background: 

Dr. Wong's research takes an interdisciplinary approach leveraging remote sensing and ecophysiology to better understand plant and ecosystem response to environment and climate change. He uses remote sensing techniques across spatial scales (leaf, canopy, drone, and satellite) and temporal scales (short-term stress response [heat, drought, disease], phenology, intra- and inter-annual variation) to advance techniques for ecosystem monitoring and assessment, and for applications in high-throughput phenotyping in forestry and agriculture.

PI: Prof. Cassidy D'Aloia

• Cell and Developmental Biology
• Molecular Biology, Genetics & Genomics
• System and Synthetic Biology

PI: Prof. Rob Ness

Title: Understanding and Improving Heat Tolerance in Photosynthetic Cells Using the Unicellular Green Alga Chlamydomonas reinhardtii

Abstract: High temperature jeopardizes plant growth, reduces crop yields, and hinders biofuel production. This problem will only exacerbate as global warming progresses. Despite this, some of the important mechanisms employed by photosynthetic cells to regulate heat responses remain elusive. To engineer heat-tolerant crops and algae for food and biofuel, it is essential to understand how plant cells respond to and recover from high temperatures. The eukaryotic, unicellular green alga Chlamydomonas reinhardtii is an excellent model organism to study many important cellular processes, especially heat responses, due to several prominent advantages, e.g. haploid genome, fast growth, homogenous heat treatment in liquid cultures, similar photosynthesis as in land plants, and simpler gene families than land plants. A genome-saturating, mapped, indexed mutant library of Chlamydomonas is available, enabling both reverse and forward genetic screens. By using tightly controlled Chlamydomonas cultivation and heat treatment in photobioreactors and quantitative, barcoded phenotyping tools, we investigated how Chlamydomonas responded to moderate and acute high temperatures at systems-wide levels, revealed dynamic heat responses under high tempratures, and identified high-confidence, putative heat tolerance genes (HTGs) at the genome-wide levels. Many of these high-confidence HTGs are highly conserved in land plants. We selected one high-confidence HTG, HTG1, for detailed function analysis. HTG1 transcripts in both Chlamydomonas and Arabidopsis were heat-inducible and the corresponding mutants were heat-sensitive, suggesting the information gained in Chlamydomonas can be transformed into land plants to improve crop thermotolerance and we can accelerate gene function analysis in land plants by using Chlamydomonas.

Research Background: Dr. Zhang's research focuses on photosynthesis, covering plant physiology, algal genomics, and organelle evolution. During her PhD at the University of Wisconsin-Madison, she studied high-temperature effects on Arabidopsis and tobacco. As a postdoc at the Carnegie Institution, she developed tools for Chlamydomonas reinhardtii, identifying photosynthesis-deficient mutants and creating a mutant library. She also researched the photo-acclimation of Paulinella chromatophora. Passionate about abiotic stress responses in photosynthesis, Ru aims to engineer it for better agriculture and biofuels. Outside of research, she enjoys cooking, gardening, and spending time with her two sons, Zoran and Roger, and started her lab at Danforth in 2016.

Zhang Lab Website: Home | Mysite

PI: Prof. Kara Layton

Title: Hot topics in 'cool' adaptations: how Canada's invertebrates survive the winter

Abstract: In Canada's winters, animals must contend with subzero temperatures. Some species migrate, others find warm microhabitats, and yet others just develop the impressive ability to either prevent or survive ice crystal growth at very low temperatures. Our lab studies the ability of boreal forest pest eastern spruce budworm as well as West Coast intertidal invertebrates to survive and thrive in subzero conditions. We work on everything from the biochemistry of ice binding proteins and the biosynthesis of cryoprotectants through to the impacts of winters on population growth and distribution. In a world where winters are changing rapidly, a better understanding of cold and its impacts will help us make better predictions for species ranges in the future. 

Marshall Lab website: Marshall Lab @ UBC
 

PI: Prof. John Ratcliffe

Title: Migration ecophysiology: the influence of heterothermy in migrating bats and birds

Abstract:

Migration has long fascinated biologists and the public alike. Many small-bodied bats and birds make amazing migratory journeys each year, leading to the inevitable question- How do they do it? As a graduate student studying bat migration, there was little bat literature that I could rely on and instead I used migratory birds as a model. I published a review titled “What can birds tell us about the migration physiology of bats?” in which I outlined the many aspects of migration that I hypothesized would be similar in the two groups, and a few key differences. My research quickly made it clear that the ability to use daily torpor to reduce energetic costs during non-flight periods has a dramatic effect on nearly all aspects of bat migration, including body composition, stopover duration, landscape scale movement patterns, and possibly even survival likelihood. We continue to study bat migration, but have also turned the question around, asking “What can bats tell us about the migration physiology of birds?”. Our recent studies of migrating songbirds have documented many species using some degree of heterothermy, indicating that heterothermic migration strategies in birds may be more common than previously appreciated. Although passerine birds don’t use deep torpor as observed in migrating bats, the use of shallow torpor can reduce the rest-phase energy budget by 20 – 40%. Taken together, it is now clear from empirical, theoretical, and evolutionary studies that variation in thermoregulatory strategy is an important factor for understanding the ecology and evolution of migration.

PI: Prof. Rosalind Murray

Title: The genetic and neural basis of female rejection behaviour

Abstract: Female preference usually determines whether or not mating occurs within a species, and can serve as a barrier between species. However, very little is known about the genes and neurons affecting female rejection behaviour. My lab uses genetic and neural tools in Drosophila to identify and characterize the fundamental underlying basis of female receptivity, and have identified individual single nucleotide polymorphisms and single neurons affecting variation in female mate rejection. I will present our exciting recent results.

PI: Prof. Baohua Liu 

Title: Primary cilia, underappreciated signaling sensors in the brain

Research Background: Dr. Guo completed her BS degree in Molecular and Cellular Biology at Jilin University, China. She completed her postdoctoral training with Dr. Eva Anton at the University of North Carolina at Chapel Hill.Dr. Guo's research aims to understand how neural circuits are constructed in development and disease, focusing on the primary cilium, a critical signaling structure in cells. The goal of her research is to uncover key mechanisms involved in neural circuit formation and to enhance understanding of the genetic and environmental factors contributing to neurodevelopmental disorders.

Guo Lab Website: HOME | Guo Lab

PI: Prof. Helene Wagner

Title: Producing wood at least cost to biodiversity and the climate

Abstract: Global wood demand is expected to increase by 50% by 2050, and the footprint of managed forests are expanding to meet this demand. What are the pathways to reducing impacts of wood harvest on global biodiversity and carbon sequestration? I’ll begin by reporting on a long-term study focused on local-scale impacts of intensive wood production on biodiversity. Second, I will present some recent research on how forestry practices in eastern Canada have affected bird populations and carbon storage. Finally, I will discuss some landscape and global-scale options for reducing tradeoffs between wood production with biodiversity conservation.