Publications by authors named "Courtney Gardner"

Following wildfires, partially combusted biomass remains on the forest floor and erosion from the landscape can release dissolved pyrogenic organic matter (dPyOM) to surface waters. Therefore, post-fire alterations to dissolved organic matter (DOM) in aquatic systems may play a vital role in DOM stability and biogeochemical cycles. Dissolved PyOM biodegradation remains poorly understood and is expected to vary with combustion temperature and fuel source.

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Microplastics, fragmented plastic particles with a maximum dimension <5 mm, are an emerging contaminant of concern that can also serve as a vector of other chemical and biological contaminants. Compared to chemical contaminants, the potential of microplastics to adsorb biological microcontaminants such as antibiotic resistance genes, small interference RNAs, and pathogenic viruses is not well understood. Many current microplastic studies are based in the aquatic environment (freshwater, seawater, and wastewater), even though the terrestrial environment is considered both an important sink and source of microplastics.

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Article Synopsis
  • This project investigates the impact of stormwater as a source of toxic tire wear particle (TWP) contaminants on aquatic life, specifically focusing on coho salmon mortality.
  • Researchers analyzed bacterial communities in urban and rural stormwater, finding more diversity in rural areas and discovering that some bacteria can degrade TWP contaminants as their main food source.
  • The study suggests that certain stormwater bacteria could be utilized for improving stormwater quality management due to their ability to break down harmful contaminants.
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Rising global populations have amplified food scarcity across the world and ushered in the development of genetically modified (GM) crops to overcome these challenges. Cultivation of major crops such as corn and soy has favoured GM crops over conventional varieties to meet crop production and resilience needs. Modern GM crops containing small interference RNA molecules and antibiotic resistance genes have become increasingly common in the United States.

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Background: Patent ductus arteriosus (PDA) is associated with significant morbidity and mortality in preterm infants. Cyclooxygenase inhibitors (COX-I) may prevent PDA-related complications. Controversy exists on which COX-I drug is the most effective and has the best safety profile in preterm infants.

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More sustainable approaches to agriculture are urgently needed to protect existing resources and optimize crop yields and to provide food for a growing global human population. More sustainable agricultural practices that utilize plant-microbe relationships across cultivation are urgently needed. The main objectives of this study were to track the prokaryotic and fungal microbiomes associated with key growth stages of developing maize to evaluate the relationships among nitrogen cycling bacteria and major fungal genera including those known to contain arbuscular mycorrhizal fungi and other important taxa.

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Stormwater is a largely uncontrolled source of pollution in rural and urban environments across the United States. Concern regarding the growing diversity and abundance of pollutants in stormwater, as well as their impacts on water quality, has grown significantly over the past several decades. In addition to conventional contaminants like nutrients and heavy metals, stormwater is a well-documented source of many contaminants of emerging concern, which can be toxic to both aquatic and terrestrial organisms and remain a barrier to maintaining high quality water resources.

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Article Synopsis
  • Patent ductus arteriosus (PDA) is a common heart condition in preterm infants, and there's uncertainty about the best treatment, with practices varying across Canadian neonatal intensive care units (NICUs).
  • This study aims to compare the effectiveness of different medications—indomethacin, ibuprofen, and acetaminophen—in treating PDA in extremely preterm infants (born before 29 weeks gestation).
  • The main goal is to assess the failure rate of these treatments, looking at the need for additional medical or surgical intervention, along with other related clinical outcomes.
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Due to the sequence homology between the bacterial 16S rRNA gene and plant chloroplast and mitochondrial DNA, the taxonomic characterization of plant microbiome using amplicon-based high throughput sequencing often results in the overwhelming presence of plant-affiliated reads, preventing the thorough description of plant-associated microbial communities. In this work we developed a PCR blocking primer assay targeting the taxonomically informative V5-V6 region of the 16S rRNA gene in order to reduce plant DNA co-amplification, and increase diversity coverage of associated prokaryotic communities. Evaluation of our assay on the characterization of the prokaryotic endophytic communities of Zea mays, Pinus taeda and Spartina alternifora leaves led to significantly reducing the proportion of plant reads, yielded 20 times more prokaryotic reads and tripled the number of detected OTUs compared to a commonly used V5-V6 PCR protocol.

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Background: People with multiple sclerosis (MS) are at increased risk for cognitive impairment, mental health concerns, and psychosocial issues, which can negatively affect disease outcomes and quality of life. Current MS care guidelines recommend integrated interdisciplinary services to address these concerns; however, issues can be overlooked during routine care. To date, there is inadequate research on how often these issues are identified and addressed during routine MS care.

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The consumption of transgenic crops and their by-products has become increasingly common in the United States. Yet, uncertainty remains regarding the fate and behavior of DNA within food matrices once it exits the digestive track and enters into wastewater treatment plants (WWTPs). Because many transgenic crops have historically contained antibiotic resistance genes as selection markers, understanding the behavior and uptake of these transgenes by environmental microbes is of critical importance.

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Bioremediation is a sustainable treatment strategy which remains challenging to implement especially in heterogeneous environments such as soil and sediment. Herein, we present a novel precision bioremediation framework that integrates amplicon based metagenomic analysis and chemical profiling. We applied this approach to samples obtained at a site contaminated with polycyclic aromatic hydrocarbons (PAHs).

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The use of transgenic crops has become increasingly common in the United States over the last several decades. Increasing evidence suggests that DNA may be protected from enzymatic digestion and acid hydrolysis in the digestive tract, suggesting that crop-derived transgenes may enter into wastewater treatment plants (WWTPs) intact. Given the historical use of antibiotic resistance genes as selection markers in transgenic crop development, it is important to consider the fate of these transgenes.

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Land application accounts for approximately 50% of wastewater solids disposal in the USA. Yet, little is known regarding the ecological impacts of many non-regulated chemicals found in biosolids. In most previous studies aimed at assessing ecological impacts, a model biosolid is generated by spiking high concentrations of the target chemical into a soil or biosolid.

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High concentrations of pesticides enter surface waters following agricultural application, raising environmental and human health concerns. The use of photoreactive nanoparticles has shown promise for contaminant degradation and surface water remediation. However, it remains uncertain how the complexity of natural waters will impact the photodegradation process.

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The increasing occurrence of tetrabromobisphenol A (TBBPA) in the environment is raising questions about its potential environmental health impacts as it has been shown to cause various deleterious effects in humans. The fact that the highest concentrations of TBBPA have been reported in wastewater sludge is concerning as effluent discharge and biosolids land application are likely a route by which TBBPA can be further disbursed to the environment. Our objectives in this study were to evaluate the effect of biochar (BC) and activated carbon (AC) in promoting the biodegradation of TBBPA, and characterize the response of anaerobic sludge microbial communities following amendments.

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The cultivation and consumption of transgenic crops continues to be a widely debated topic, as the potential ecological impacts are not fully understood. In particular, because antibiotic resistance genes (ARGs) have historically been used as selectable markers in the genetic engineering of transgenic crops, it is important to determine if the genetic constructs found in decomposing transgenic crops persist long enough in the environment and if they can be transferred horizontally to indigenous microorganisms. In the present study, we address the question of persistence.

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The NF-kB family of transcription factors regulates important biological functions including cell growth, survival and the immune response. We found that Human Papillomavirus type 16 (HPV-16) E7 and E6/E7 proteins inhibited basal and TNF-alpha-inducible NF-kB activity in human epithelial cells cultured from the cervical transformation zone, the anatomic region where most cervical cancers develop. In contrast, HPV-16 E6 regulated NF-kB in a cell type- and cell growth-dependent manner.

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