16 research outputs found
No common pesticides detected in snow buntings utilizing a farmland landscape in eastern Québec
Many species of migratory birds are declining worldwide, including throughout North America. Some of the most cited causes of decline are linked to climate change, urbanization, and growth in agriculture. Across eastern Canada, a number of insecticides and herbicides are commonly sprayed before and during the grain growing season to control pests and foliage competitors. During wintering and migration, a declining Arctic-breeding songbird, the snow bunting (Plectrophenax nivalis), utilizes open farmlands of southern Canada; therefore, this could be a period when the species is most exposed to these pesticides. We tested snow bunting tissues (blood and liver) for the 4 pesticides most commonly used in grain agriculture in Canada: atrazine, chlothianidin, imidacloprid, and glyphosate, as well as a glyphosate derivative (aminomethylphosphic acid, AMPA). Although this species is thought to forage in grain fields during autumn through spring, we found no detectable traces of any of the five substances. Wintering buntings may either not be exposed to these pesticides during their presence in agriculture fields or, given the rapid turnover of these pesticides in the blood and tissues, be exposed to doses below detection level in samples
Preclinical and Clinical Development of Plant-Made Virus-Like Particle Vaccine against Avian H5N1 Influenza
The recent swine H1N1 influenza outbreak demonstrated that egg-based vaccine manufacturing has an Achille's heel: its inability to provide a large number of doses quickly. Using a novel manufacturing platform based on transient expression of influenza surface glycoproteins in Nicotiana benthamiana, we have recently demonstrated that a candidate Virus-Like Particle (VLP) vaccine can be generated within 3 weeks of release of sequence information. Herein we report that alum-adjuvanted plant-made VLPs containing the hemagglutinin (HA) protein of H5N1 influenza (A/Indonesia/5/05) can induce cross-reactive antibodies in ferrets. Even low doses of this vaccine prevented pathology and reduced viral loads following heterotypic lethal challenge. We further report on safety and immunogenicity from a Phase I clinical study of the plant-made H5 VLP vaccine in healthy adults 18-60 years of age who received 2 doses 21 days apart of 5, 10 or 20 µg of alum-adjuvanted H5 VLP vaccine or placebo (alum). The vaccine was well tolerated at all doses. Adverse events (AE) were mild-to-moderate and self-limited. Pain at the injection site was the most frequent AE, reported in 70% of vaccinated subjects versus 50% of the placebo recipients. No allergic reactions were reported and the plant-made vaccine did not significantly increase the level of naturally occurring serum antibodies to plant-specific sugar moieties. The immunogenicity of the H5 VLP vaccine was evaluated by Hemagglutination-Inhibition (HI), Single Radial Hemolysis (SRH) and MicroNeutralisation (MN). Results from these three assays were highly correlated and showed similar trends across doses. There was a clear dose-response in all measures of immunogenicity and almost 96% of those in the higher dose groups (2 × 10 or 20 µg) mounted detectable MN responses. Evidence of striking cross-protection in ferrets combined with a good safety profile and promising immunogenicity in humans suggest that plant-based VLP vaccines should be further evaluated for use in pre-pandemic or pandemic situations.ClinicalTrials.gov NCT00984945
High methylmercury in Arctic and subarctic ponds is related to nutrient levels in the warming eastern Canadian Arctic
Permafrost thaw ponds are ubiquitous in the eastern
Canadian Arctic, yet little information exists on their potential as
sources of methylmercury (MeHg) to freshwaters. They are
microbially active and conducive to methylation of inorganic
mercury, and are also affected by Arctic warming. This multiyear
study investigated thaw ponds in a discontinuous permafrost region
in the Subarctic taiga (Kuujjuarapik-Whapmagoostui, QC) and a
continuous permafrost region in the Arctic tundra (Bylot Island,
NU). MeHg concentrations in thaw ponds were well above levels
measured in most freshwater ecosystems in the Canadian Arctic
(>0.1 ng L−1). On Bylot, ice-wedge trough ponds showed
significantly higher MeHg (0.3−2.2 ng L−1) than polygonal
ponds (0.1−0.3 ng L−1) or lakes (<0.1 ng L−1). High MeHg was
measured in the bottom waters of Subarctic thaw ponds near
Kuujjuarapik (0.1−3.1 ng L−1). High water MeHg concentrations in thaw ponds were strongly correlated with variables
associated with high inputs of organic matter (DOC, a320, Fe), nutrients (TP, TN), and microbial activity (dissolved CO2 and
CH4). Thawing permafrost due to Arctic warming will continue to release nutrients and organic carbon into these systems and
increase ponding in some regions, likely stimulating higher water concentrations of MeHg. Greater hydrological connectivity
from permafrost thawing may potentially increase transport of MeHg from thaw ponds to neighboring aquatic ecosystems
No common pesticides detected in snow buntings utilizing a farmland landscape in eastern Québec
Many species of migratory birds are declining worldwide, including throughout North America. Some of the most cited causes of decline are linked to climate change, urbanization, and growth in agriculture. Across eastern Canada, a number of insecticides and herbicides are commonly sprayed before and during the grain growing season to control pests and foliage competitors. During wintering and migration, a declining Arctic-breeding songbird, the snow bunting (Plectrophenax nivalis), utilizes open farmlands of southern Canada; therefore, this could be a period when the species is most exposed to these pesticides. We tested snow bunting tissues (blood and liver) for the 4 pesticides most commonly used in grain agriculture in Canada: atrazine, chlothianidin, imidacloprid, and glyphosate, as well as a glyphosate derivative (aminomethylphosphic acid, AMPA). Although this species is thought to forage in grain fields during autumn through spring, we found no detectable traces of any of the five substances. Wintering buntings may either not be exposed to these pesticides during their presence in agriculture fields or, given the rapid turnover of these pesticides in the blood and tissues, be exposed to doses below detection level in samples