Timing, Magnitude, and Isotopic Composition of Nitrate Leached Under Red Raspberries Over an Unconfined Aquifer With High Annual Recharge

The highly conductive, trans-boundary Abbotsford-Sumas Aquifer (ASA) has a decadal scale history of nitrate contamination linked to high groundwater recharge and intensive agricultural land use including livestock and perennial berry (particularly raspberries) production. This thesis aimed to better understand the controls on nitrate leaching under raspberries over the ASA. To achieve this, the temporal and spatial variability of nitrate leaching under experimental and commercially managed stands were examined using Passive Capillary wick Samplers below the root zone and high-resolution passive diffusion samplers in the shallow groundwater. High seasonal variation was observed when comparing the δ15NNO3 values of leachate nitrate collected under experimental plots receiving either fertilizer (-2.4 to +8.7 ‰) or manure (+1.6 to +9.6 ‰), which, in many cases, precluded a clear distinction between the two treatment nitrate sources. Some of this seasonal variation was attributed to the application of growing season irrigation. Likewise, the unexpectedly high proportion of annual nitrate leaching under commercially managed raspberries during spring and summer (29 and 39%) was attributed to growing season irrigation. Although the irrigation water and fertilizer were placed only along the raspberry rows, approximately 60 % of nitrate leaching occurred under the alley areas between the rows, indicating that improved alley management may be important for managing nitrate leaching losses. Raspberry stand renovation (canes chopped, soil fumigated and tilled, and manure applied before replanting), which typically occurs every 6-10 years in response to decreased crop vigour, resulted in 246 kg-N-ha-1 leached under the commercial stand during the year following manure application and replanting compared to an average of 72 kg-N-ha-1 during later years. Results from this study site suggests that for a 10-year renovation cycle, approximately 23 % of the nitrate loading to groundwater could be attributed to renovation practices. The magnitude and isotopic composition of nitrate leaching were highly spatially and temporally (seasonally and inter-annually) variable. Characterizing this variation is key to targeting and assessing improved management practices for mitigating groundwater nitrate-N. Improved irrigation and alley management, reducing manure applications, and increasing the time between renovations can potentially decrease groundwater nitrate-N concentrations over the long-term

Quantifying Nitrate Leaching under Commercial Red Raspberry Using Passive Capillary Wick Samplers

Groundwater NO–N contamination in the Abbotsford-Sumas Aquifer in British Columbia, Canada, has been attributed primarily to NO–N leaching from red raspberry ( L.); however, direct estimates of NO–N leaching are lacking. This study quantified the magnitude and timing of NO–N leaching under a commercial red raspberry field over 30 mo (October 2010–March 2013) using passive capillary wick samplers installed below the root zone at three row locations (irrigated row, nonirrigated row, and alley) after the critical period of field renovation and replanting. Substantial NO–N leaching (240 kg N ha) during the first year of monitoring was attributed to the effects of field renovation (including autumn chopping and incorporation of raspberry canes and soil fumigation and spring poultry broiler manure application) in the year prior to the initiation of monitoring. Lower NO–N leaching (80 kg N ha) occurred in the second year of monitoring under typical mineral fertilizer management practices. Strong seasonality of NO–N leaching was observed in both years, with ∼48% in autumn, 34% in spring and summer, and 17% in winter. Approximately 60% of the NO–N leaching was attributed to the alleys between raspberry rows, which did not receive mineral fertilizer or irrigation. The high proportion of leaching during spring and summer and from the alleys suggests that growing-season irrigation practices and alley vegetation management, respectively, would be good targets for the development of improved practices. The samplers were effective in quantifying the magnitude and timing of NO–N leaching from a commercial agricultural field and informing the development of improved practices

Spectrum of neurodevelopmental disease associated with the GNAO1 guanosine triphosphate-binding region

Objective To characterize the phenotypic spectrum associated with GNAO1 variants and establish genotype-protein structure-phenotype relationships. Methods We evaluated the phenotypes of 14 patients with GNAO1 variants, analyzed their variants for potential pathogenicity, and mapped them, along with those in the literature, on a three-dimensional structural protein model. Results The 14 patients in our cohort, including one sibling pair, had 13 distinct, heterozygous GNAO1 variants classified as pathogenic or likely pathogenic. We attributed the same variant in two siblings to parental mosaicism. Patients initially presented with seizures beginning in the first 3 months of life (8/14), developmental delay (4/14), hypotonia (1/14), or movement disorder (1/14). All patients had hypotonia and developmental delay ranging from mild to severe. Nine had epilepsy, and nine had movement disorders, including dystonia, ataxia, chorea, and dyskinesia. The 13 GNAO1 variants in our patients are predicted to result in amino acid substitutions or deletions in the GNAO1 guanosine triphosphate (GTP)-binding region, analogous to those in previous publications. Patients with variants affecting amino acids 207-221 had only movement disorder and hypotonia. Patients with variants affecting the C-terminal region had the mildest phenotypes.

Spectrum of neurodevelopmental disease associated with the GNAO1 guanosine triphosphate-binding region

OBJECTIVE: To characterize the phenotypic spectrum associated with GNAO1 variants and establish genotype-protein structure-phenotype relationships. METHODS: We evaluated the phenotypes of 14 patients with GNAO1 variants, analyzed their variants for potential pathogenicity, and mapped them, along with those in the literature, on a three-dimensional structural protein model. RESULTS: The 14 patients in our cohort, including one sibling pair, had 13 distinct, heterozygous GNAO1 variants classified as pathogenic or likely pathogenic. We attributed the same variant in two siblings to parental mosaicism. Patients initially presented with seizures beginning in the first 3 months of life (8/14), developmental delay (4/14), hypotonia (1/14), or movement disorder (1/14). All patients had hypotonia and developmental delay ranging from mild to severe. Nine had epilepsy, and nine had movement disorders, including dystonia, ataxia, chorea, and dyskinesia. The 13 GNAO1 variants in our patients are predicted to result in amino acid substitutions or deletions in the GNAO1 guanosine triphosphate (GTP)-binding region, analogous to those in previous publications. Patients with variants affecting amino acids 207-221 had only movement disorder and hypotonia. Patients with variants affecting the C-terminal region had the mildest phenotypes. SIGNIFICANCE: GNAO1 encephalopathy most frequently presents with seizures beginning in the first 3 months of life. Concurrent movement disorders are also a prominent feature in the spectrum of GNAO1 encephalopathy. All variants affected the GTP-binding domain of GNAO1, highlighting the importance of this region for G-protein signaling and neurodevelopment.status: publishe