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Full-Text Articles in Biology

Molecular Regulation Of The Salicylic Acid Hormone Pathway In Plants Under Changing Environmental Conditions, Christina A. M. Rossi, Eric J. R. Marchetta, Jong Hum Kim, Christian Castroverde Jan 2023

Molecular Regulation Of The Salicylic Acid Hormone Pathway In Plants Under Changing Environmental Conditions, Christina A. M. Rossi, Eric J. R. Marchetta, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

Salicylic acid (SA) is a central plant hormone mediating immunity, growth, and development. Recently, studies have highlighted the sensitivity of the SA pathway to changing climatic factors and the plant microbiome. Here we summarize organizing principles and themes in the regulation of SA biosynthesis, signaling, and metabolism by changing abiotic/biotic environments, focusing on molecular nodes governing SA pathway vulnerability or resilience. We especially highlight advances in the thermosensitive mechanisms underpinning SA-mediated immunity, including differential regulation of key transcription factors (e.g., CAMTAs, CBP60g, SARD1, bHLH059), selective protein–protein interactions of the SA receptor NPR1, and dynamic phase separation of the recently identified …


Salicylic Acid And N-Hydroxypipecolic Acid At The Fulcrum Of The Plant Immunity-Growth Equilibrium, Alyssa Shields, Vanessa Shivnauth, Christian Danve M. Castroverde Mar 2022

Salicylic Acid And N-Hydroxypipecolic Acid At The Fulcrum Of The Plant Immunity-Growth Equilibrium, Alyssa Shields, Vanessa Shivnauth, Christian Danve M. Castroverde

Biology Faculty Publications

Salicylic acid (SA) and N-hydroxypipecolic acid (NHP) are two central plant immune signals involved in both resistance at local sites of pathogen infection (basal resistance) and at distal uninfected sites after primary infection (systemic acquired resistance). Major discoveries and advances have led to deeper understanding of their biosynthesis and signaling during plant defense responses. In addition to their well-defined roles in immunity, recent research is emerging on their direct mechanistic impacts on plant growth and development. In this review, we will first provide an overview of how SA and NHP regulate local and systemic immune responses in plants. We …


Salicylic Acid: A Key Regulator Of Redox Signalling 1 And Plant Immunity, Mohd Saleem, Qazi Fariddudin, Christian Castroverde Oct 2021

Salicylic Acid: A Key Regulator Of Redox Signalling 1 And Plant Immunity, Mohd Saleem, Qazi Fariddudin, Christian Castroverde

Biology Faculty Publications

In plants, the reactive oxygen species (ROS) formed during normal conditions are essential in regulating several processes, like stomatal physiology, pathogen immunity and developmental signaling. However, biotic and abiotic stresses can cause ROS over-accumulation leading to oxidative stress. Therefore, a suitable equilibrium is vital for redox homeostasis in plants, and there have been major advances in this research arena. Salicylic acid (SA) is known as a chief regulator of ROS; however, the underlying mechanisms remain largely unexplored. SA plays an important role in establishing the hypersensitive response (HR) and systemic acquired resistance (SAR). This is underpinned by a robust and …


Temperature Regulation Of Plant Hormone Signaling During Stress And Development, Christian Castroverde, Damaris Dina Jun 2021

Temperature Regulation Of Plant Hormone Signaling During Stress And Development, Christian Castroverde, Damaris Dina

Biology Faculty Publications

Global climate change has broad-ranging impacts on the natural environment and human civilization. Increasing average temperatures along with more frequent heat waves collectively have negative effects on cultivated crops in agricultural sectors and wild species in natural ecosystems. These aberrantly hot temperatures, together with cold stress, represent major abiotic stresses to plants. Molecular and physiological responses to high and low temperatures are intricately linked to the regulation of important plant hormones. In this review, we shall highlight our current understanding of how changing temperatures regulate plant hormone pathways during immunity, stress responses and development. This article will present an overview …


Investigating The Antitumor Effects Of A Dsrna-Nanoparticle Complex In An In Vitro Ovarian Cancer Model, Aaron Lewis Jan 2021

Investigating The Antitumor Effects Of A Dsrna-Nanoparticle Complex In An In Vitro Ovarian Cancer Model, Aaron Lewis

Theses and Dissertations (Comprehensive)

An estimated 1 in 70 women will be diagnosed with ovarian cancer in their lifetime. Despite advanced detection and treatment methods, it remains a silent killer with an expected survival rate of 50%. A developing method in cancer treatment is the use of compounds that stimulate the immune system to aid in the body's fight against the disease. This project focused on the use of the potent immune stimulant double-stranded RNA (dsRNA), commercially available as polyinosinic:polycytidylic acid, poly(I:C), to induce cytotoxicity in two ovarian cancer cell lines; SKOV-3 and OVCAR-3. Some challenges exist with the delivery of dsRNA due to …


Mechanistic Insights Into Strigolactone Biosynthesis, Signaling And Regulation During Plant Growth And Development, Kaiser Iqbal Wani, Andleeb Zehra, Sadaf Choudhary, M Naeem, M. Masroor A. Khan, Christian Danve Castroverde, Tariq Aftab Oct 2020

Mechanistic Insights Into Strigolactone Biosynthesis, Signaling And Regulation During Plant Growth And Development, Kaiser Iqbal Wani, Andleeb Zehra, Sadaf Choudhary, M Naeem, M. Masroor A. Khan, Christian Danve Castroverde, Tariq Aftab

Biology Faculty Publications

Strigolactones (SLs) constitute a group of carotenoid-derived phytohormones with butenolide moieties. These hormones are involved in various functions, including regulation of secondary growth, shoot branching and hypocotyl elongation, and stimulation of seed germination. SLs also control hyphal branching of arbuscular mycorrhizal (AM) fungi, and mediate responses to both abiotic and biotic cues. Most of these functions stem from the interplay of SLs with other hormones, enabling plants to appropriately respond to changing environmental conditions. This dynamic interplay provides opportunities for phytohormones to modulate and augment one another. In this article, we review our current mechanistic understanding of SL biosynthesis, receptors …


Diversity, Function And Regulation Of Cell Surface And Intracellular Immune Receptors In Solanaceae, Jong Hum Kim, Christian Castroverde Apr 2020

Diversity, Function And Regulation Of Cell Surface And Intracellular Immune Receptors In Solanaceae, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

The first layer of the plant immune system comprises plasma membrane-localized receptor proteins and intracellular receptors of the nucleotide-binding leucine-rich repeat protein superfamily. Together, these immune receptors act as a network of surveillance machines in recognizing extracellular and intracellular pathogen invasion-derived molecules, ranging from conserved structural epitopes to virulence-promoting effectors. Successful pathogen recognition leads to physiological and molecular changes in the host plants, which are critical for counteracting and defending against biotic attack. A breadth of significant insights and conceptual advances have been derived from decades of research in various model plant species regarding the structural complexity, functional diversity and …


Investigation Of Rna Interference (Rnai)-Mediated Gene Silencing In Rainbow Trout, Sarah Au Jan 2020

Investigation Of Rna Interference (Rnai)-Mediated Gene Silencing In Rainbow Trout, Sarah Au

Theses and Dissertations (Comprehensive)

RNA interference (RNAi) was first characterized in plants and invertebrates as an antiviral innate immune response. It is a natural antiviral defence mechanism to degrade viral RNA by virus-induced gene silencing. Studies showed synthetic long double-stranded RNA (dsRNA; >30bp) degraded Caenorhabditis elegans messenger RNA (mRNA) transcripts, resulting in sequence-dependent gene silencing. Currently, there is only limited research on RNAi in fish, particularly the use of long dsRNA to trigger sequence-specific gene silencing. This is because studies have shown long dsRNAs trigger interferon response that could mask gene-specific RNAi effects. This thesis explored long dsRNA-mediated RNAi pathways in rainbow trout cells …


Investigating The Antiviral Effects Of Vig-3 From Rainbow Trout, Shanee Herrington-Krause Jan 2019

Investigating The Antiviral Effects Of Vig-3 From Rainbow Trout, Shanee Herrington-Krause

Theses and Dissertations (Comprehensive)

Rainbow trout is the most farmed fish in Ontario, and thus is economically important to the province. Despite this, there is a lack of understanding regarding fish innate immunity, specifically with regards to interferon-stimulated genes (ISGs) and their antiviral effector functions. ISGs are the workhorses of the innate antiviral response, operating together to limit each step of virus replication. The Viral Hemorrhagic Septicemia Virus (VHSV) induced gene (Vig)-3 is a newly identified ISG within many fish species and is homologous to ISG-15 in mammals. It is a small ubiquitin-like protein inducible by type I interferon (IFN-I), and is suggested to …


Charecterization Of The Innate Immune Response In The Rat Intervertebral Disc At The Tissue And Cellular Level, Matthew Guerreiro Jan 2018

Charecterization Of The Innate Immune Response In The Rat Intervertebral Disc At The Tissue And Cellular Level, Matthew Guerreiro

Theses and Dissertations (Comprehensive)

Low back pain (LBP) affects up to 80% of the global population at some point during their life. The costs associated with LBP are estimated at $100 billion per year, putting significant strains on our healthcare system. As intervertebral disc (IVD) herniation is one of the major causes of LBP we decided to focus on herniation facilitated inflammatory responses, where damage caused by herniation triggers an innate immune response which likely results in pain, inflammation, and recruitment of specialized innate immune cells like macrophages to the affected area. Since the role of the inflammatory response is relatively uncharacterized in the …


Characterizing Dsrna Production In Virus-Infected Fish Cells, Amal Brek Aloufi Jan 2014

Characterizing Dsrna Production In Virus-Infected Fish Cells, Amal Brek Aloufi

Theses and Dissertations (Comprehensive)

Viral dsRNA is produced by almost all viruses sometime during their replicative cycle. These viral nucleic acids are potent inducers of both innate and adaptive immune responses, and are therefore considered important immuno-modulators. Previous studies have shown that viruses produce dsRNA when replicating in mammalian cells; however, to date no one has demonstrated viral dsRNA production in virus infected fish cells. Therefore, the goal of this study is to investigate dsRNA production by fish viruses in fish cells, verifying production and performing initial characterization of the dsRNA molecules being produced. Three different rainbow trout cell lines were used in this …


A Structure-Function Analysis Of The Arabidopsis Chloroplast Import Protein Attic20, James H. Campbell Jan 2014

A Structure-Function Analysis Of The Arabidopsis Chloroplast Import Protein Attic20, James H. Campbell

Theses and Dissertations (Comprehensive)

Arabidopsis thaliana protein Tic20 (atTic20) is a member of the translocon at the inner envelope membrane of chloroplasts. Evidence to date suggests it is part of the main preprotein conducting aperture in the complex, but its exact role is still debated. To help characterize its role, a protocol optimizing yield and purity of recombinantly expressed atTic20 was developed, and a series of experiments was performed to examine its secondary structure and its ability to interact with chloroplast transit peptides. The attempt to increase protein yield was successful, with growth at 20oC in the auto-inducing media ZYP-5052 showing the …


The Establishment Of A Fibroblastic Cell Line From Yellow Perch (Perca Flavescens) And Its Potential Applications In Toxicology, Katelin W. Spiteri Jan 2014

The Establishment Of A Fibroblastic Cell Line From Yellow Perch (Perca Flavescens) And Its Potential Applications In Toxicology, Katelin W. Spiteri

Theses and Dissertations (Comprehensive)

This thesis describes the establishment, characterization and potential toxicological applications of YPF5, a yellow perch cell line. YPF5 is a fibroblastic cell line derived from the caudal fin of yellow perch. This cell line has been maintained for over 2 years. Cultures have been passaged over 60 times, and successfully cryopreserved and thawed. YPF5 is grown at room temperature in Leibovitz-15 (L-15) media, supplemented with 10% fetal bovine serum and 3% penicillin-streptomycin. The origin of YPF5 has been confirmed as Perca flavescens through “DNA Barcoding” and reaffirmed through Karyotyping (2n = 48) as per literature reported karyology for percidae including …