Wetland- and landscape-level effects on scoter (Melanitta spp.), scaup (Aythya spp.), and macroinvertebrates in wetlands of the Central Mackenzie Valley, Northwest Territories

North American breeding populations of scoters (Melanitta spp.) and scaup (Aythya spp.), which nest predominantly in the rapidly changing boreal forest, were over 20% lower 2005–2014 in the western boreal forest compared to long-term averages (1955–2014), yet habitat needs for these duck species remain poorly documented. The purpose of my research is to predict impacts of ongoing environmental changes on waterfowl food supplies in northern areas and to prioritize key habitats for conservation of these species. At a key waterfowl breeding site in Canada’s boreal forest, I tested three main hypotheses: (i) trophic enrichment – Wetlands located in areas burned by recent wildfires would be characterized by higher nutrient and productivity levels, and unique macroinvertebrate communities, versus those wetlands in unburned areas; (ii) foraging habitat limitation – Variables describing foraging habitat availability would be the best predictors of scoter and scaup occurrence; and (iii) scale dependency – The spatial scales at which landscape variables affected duck occurrence would correspond with home range size. To test my first hypothesis, I measured levels of nitrogen, phosphorous, and chlorophyll-a concentrations, as well as macroinvertebrate community characteristics, in burned and unburned wetlands. Consistent with my predictions, total phosphorous and chlorophyll-a levels were approximately two-fold higher in burned than in unburned wetlands, although this effect was seasonally variable. Conversely, total nitrogen levels were similar in burned and unburned wetlands. For macroinvertebrate community composition, results were not as expected – on average, samples from burned and unburned wetlands contained similar taxa in similar abundances. To test my second and third hypotheses, I applied a multi-scale regression approach, using aerial breeding waterfowl survey data and remotely sensed landscape composition variables on unburned wetlands to evaluate relationships between landscape variables and habitat use. As predicted, wetland size correlated strongly and positively with scoter and scaup occurrence. In contrast, the amount of different land cover types correlated only weakly with occurrence. For scoters, the most important landscape variables were total number and area of waterbodies/km2, while the proportion wetland cover was the most important landscape variable for scaup followed by total waterbody area/km2. However, for both scoter and scaup, some of these relationships were negative, contrary to my predictions. I also found that scoters had a larger average scale of effect than scaup, as expected based on the size of their home ranges. Taken together, these results suggest that wetland ecosystems in the northwestern boreal forest are resilient to, and may even benefit from, moderate to severe fires under current climate conditions. However, fire impacts on aquatic ecosystems are likely to intensify as the climate warms, such that this resilience may not be maintained in coming decades. The results also suggest that scoter and scaup foraging habitat is limited in the study site and that wetland-level conservation for scoter and scaup pairs should be informed primarily by wetland characteristics (e.g., wetland size and amphipod abundance) and less so by landscape composition (e.g., proportion coniferous forest cover) surrounding wetlands. In addition, the findings indicate that future landscape-level predictive modelling for these duck species should include species-specific, scale-optimized variables and should focus on home range selection

Comparative Analysis Of Zebrafish And Planarian Model Systems For Developmental Neurotoxicity Screens Using An 87-Compound Library

There is a clear need to establish and validate new methodologies to more quickly and efficiently screen chemicals for potential toxic effects, particularly on development. The emergence of alternative animal systems for rapid toxicology screens presents valuable opportunities to evaluate how systems complement each other. In this article, we compare a chemical library of 87-compounds in two such systems, developing zebrafish and freshwater planarians, by screening for developmental neurotoxic effects. We show that the systems’ toxicological profiles are complementary to each other, with zebrafish yielding more detailed morphological endpoints and planarians more behavioral endpoints. Overall, zebrafish was more sensitive to this chemical library, yielding 86/87 hits, compared to 50/87 hits in planarians. The difference in sensitivity could not be attributed to molecular weight, Log Kow or the bioconcentration factor. Of the 87 chemicals, 28 had previously been evaluated in mammalian developmental neuro- (DNT), neuro- or developmental toxicity studies. Of the 28, 20 were hits in the planarian, and 27 were hits in zebrafish. Eighteen of the 28 had previously been identified as DNT hits in mammals and were highly associated with activity in zebrafish and planarian behavioral assays in this study. Only 1 chemical (out of 28) was a false negative in both zebrafish and planarian systems. Differences in endpoint coverage and system sensitivity illustrate the value of a dual systems approach to rapidly query a large chemical-bioactivity space and provide weight-of-evidence for prioritization of chemicals for further testing

Impact of Commercial Thinning on Annual Radial Growth and Wood Density in Plantation-Grown Black Spruce

This study examined ring width and density of plantation-grown black spruce 6 yr after commercial thinning (CT). Sample trees were from a 49-yr-old plantation receiving CT at age 43 yr near Kapuskasing, Ontario, Canada. There was a significant and positive effect on annual radial growth for heavy thinning (one of three rows removed) but not for light thinning (one of four rows removed). CT had little effect on wood density. Increased radial growth caused by thinning was mainly from an increase in earlywood width. Latewood proportion was not affected by thinning. With increasing tree diameter from 100-220 mm, ring width increased 0.93-2.19 mm, whereas ring density decreased slightly 523-487 kg/m3. Ring width decreased from 1.31 mm at stump height to 1.13 mm at 2.5-m height and then increased to 1.62 mm at 7.5-m height. From stump height to 7.5 m, ring density decreased steadily from 525-491 kg/m3. The effect of thinning depended on tree diameter and height position. This study suggests CT in black spruce accelerated radial growth but had little effect on wood density. Appropriate thinning intensity may target radial growth increase to trees of certain diameters

Multifunctional surface modifications to capture and expand flowing endothelial colony- forming cells

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Key Issues in the Modes of Action and Effects of Trichloroethylene Metabolites for Liver and Kidney Tumorigenesis

Trichloroethylene (TCE) exposure has been associated with increased risk of liver and kidney cancer in both laboratory animal and epidemiologic studies. The U.S. Environmental Protection Agency 2001 draft TCE risk assessment concluded that it is difficult to determine which TCE metabolites may be responsible for these effects, the key events involved in their modes of action (MOAs), and the relevance of these MOAs to humans. In this article, which is part of a mini-monograph on key issues in the health risk assessment of TCE, we present a review of recently published scientific literature examining the effects of TCE metabolites in the context of the preceding questions. Studies of the TCE metabolites dichloroacetic acid (DCA), trichloroacetic acid (TCA), and chloral hydrate suggest that both DCA and TCA are involved in TCE-induced liver tumorigenesis and that many DCA effects are consistent with conditions that increase the risk of liver cancer in humans. Studies of S-(1,2-dichlorovinyl)-l-cysteine have revealed a number of different possible cell signaling effects that may be related to kidney tumorigenesis at lower concentrations than those leading to cytotoxicity. Recent studies of trichloroethanol exploring an alternative hypothesis for kidney tumorigenesis have failed to establish the formation of formate as a key event for TCE-induced kidney tumors. Overall, although MOAs and key events for TCE-induced liver and kidney tumors have yet to be definitively established, these results support the likelihood that toxicity is due to multiple metabolites through several MOAs, none of which appear to be irrelevant to humans

A General Framework for Interrogation of mRNA Stability Programs Identifies RNA-Binding Proteins that Govern Cancer Transcriptomes

Widespread remodeling of the transcriptome is a signature of cancer; however, little is known about the post-transcriptional regulatory factors, including RNA-binding proteins (RBPs) that regulate mRNA stability, and the extent to which RBPs contribute to cancer-associated pathways. Here, by modeling the global change in gene expression based on the effect of sequence-specific RBPs on mRNA stability, we show that RBP-mediated stability programs are recurrently deregulated in cancerous tissues. Particularly, we uncovered several RBPs that contribute to the abnormal transcriptome of renal cell carcinoma (RCC), including PCBP2, ESRP2, and MBNL2. Modulation of these proteins in cancer cell lines alters the expression of pathways that are central to the disease and highlights RBPs as driving master regulators of RCC transcriptome. This study presents a framework for the screening of RBP activities based on computational modeling of mRNA stability programs in cancer and highlights the role of post-transcriptional gene dysregulation in RCC. Perron et al. develop a computational approach that models the functional activity of RBPs in individual cancer samples by monitoring their associated RNA stability programs. Applying this method to renal cell carcinoma transcriptomes, the authors identify RBPs that enhance cancer-associated pathways including hypoxia and cell cycle

918-7 Limitations of Percutaneous Interventions in the Treatment of Bifurcation Lesions Involving the Left Anterior Descending Coronary Artery

Serious complications may occur when intervention is unsuccessful in bifurcation lesions involving the left anterior descending (LAD) and first major diagonal (D), because of the large amount of involved myocardium. To determine this complication rate, we reviewed 82 consecutive cases, over a 3 year period, in which these lesions were attempted. Sixty-six percent of the subjects were male, and 37% had unstable angina. The mean age was 59 and the mean ejection fraction was 56%. Digital calipers were used to measure vessel minimum lumen (MLD) and reference diameters. For the LAD the final MLD was 1.81mm and for the 0 1.32mm. The final percent mean diameter stenoses for the LAD and D were 41% and 45%, respectively. There were no significant differences in the rates of success or complication between groups treated with angioplasty only (N=68) or directional atherectomy (N=14). The in-hospital event-free success rate was 55%. The in-hospital complication rates were:Recurrent Ischemia16%Ventricular Tachycardia2%Myocardial Infarction14%Stroke2%Bypass Surgery12%Death1%Repeat Procedure4%Composite34%ConclusionLAD bifurcation lesion intervention is associated with a high in-hospital complication rate. Since these lesions are not amenable to stent placement or atherectomy with simultaneous protection of both vessels, these cases should be carefully evaluated before intervention, and bypass surgery should be considered as a treatment option

El proyecto genómico del hongo Ophiostoma

The Canadian Ophiostoma Genome Project, which was initiated in 2001, is a collaborative effort between research teams in four different universities. Its general objective is to conduct a large-scale identification and analysis of genes controlling important aspects of the life cycle of Ophiostomatoid fungi. To this end, several expressed sequence tag (EST) libraries were obtained for the Dutch elm disease pathogen Ophiostoma novo-ulmi and the sapstainer O. piceae, following partial, single-pass automated sequencing of complementary DNA clones. The largest EST library, prepared from yeast like cells of O. novo-ulmi grown at 24 °C, contains over 3,400 readable sequences and serves as a general reference library for Ophiostomatoid fungi. Smaller, specific EST libraries were constructed from mycelia of O. novo-ulmi grown at suboptimal temperatures, from perithecia formed in laboratory crosses, as well as from O. piceae grown on different carbon sources. Ongoing bioinformatic searches in public databases have so far identified over 750 Ophiostoma unique ESTs which show significant homology with other fungal genes of known function, although a high proportion of Ophiostoma ESTs are either orphans (no match to any known gene) or show homology to genes of unknown function. In addition to EST analysis, differential expression of selected genes and structural genomics are also being studied.El programa canadiense sobre el genoma de Ophiostoma, iniciado en 2001, es una colaboración entre equipos de investigación de cuatro universidades diferentes. Su objetivo general es el desarrollo de la identificación y análisis a gran escala de los genes que controlan algunos aspectos importantes del ciclo vital de los hongos de Ophiostoma. Con este fin, se ha obtenido diversas bibliotecas de marcadores de secuencias expresadas (bibliotecas EST) para la el patógeno de la grafiosis Ophiostoma novo-ulmi y para el hongo de tinción vascular O. piceae, seguido de una secuenciación automática parcial de un único paso de clones complementarios de ADN. La mayor biblioteca EST, preparada a partir de conidios de O. novo-ulmi cultivadas a 24 ºC, contiene más de 3.400 secuencias legíbles, y sirve como biblioteca de referencia para los hongos de Ophiostoma. Se han desarrollado bibliotecas específicas menores a partir de micelios de O. novo-ulmi cultivados a temperaturas sub-óptimas, a partir de los peritecios formados en cruces realizados en laboratorio, así como a partir de O. piceae cultivado en distintas fuentes de carbón. Las búsquedas bioinformáticas en bases de datos públicas han permitido identificar hasta ahora más de 750 EST exclusivos de Ophiostoma, lo que muestra una significativa homología con otros genes fúngicos de función conocida, aunque una alta proporción de los EST de Ophiostoma son o bien huérfanos (no relacionados con ningún gen conocido), o bien muestran homología con genes cuya función es desconocida. Además del análisis EST, la expresión diferencial de genes seleccionados y la estructura genómica están siendo también estudiadas