21 research outputs found

    A Herpetological Survey of the James Bay Area of Québec and Ontario

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    In May-June 2002, as part of a survey of a variety of taxa in the James Bay region of Ontario and Québec, we surveyed the poorly documented herpetofauna of this region. In Ontario we visited sites near Moosonee that FWS had previously surveyed in 1971-1972, and continued ongoing herpetological monitoring around Cochrane. In Québec we surveyed the inland James Bay Road, and roads to four settlements along the coast. American Toad (Anaxyrus americanus), Spring Peeper (Pseudacris crucifer), and Wood Frog (Lithobates sylvaticus) were widespread and abundant throughout. Blue-spotted Salamander (Ambystoma laterale) and Garter Snake (Thamnophis sirtalis) were widespread and common in Québec and at the study site near Cochrane. We obtained the first taped calls and voucher specimen of the Boreal Chorus Frog (Pseudacris maculata) from Québec, and failed to find it at the settlement and airport of Moosonee where it had been present in 1972. A significant range extension was for the Two-lined Salamander (Eurycea bislineata), which we found 200 km north of its previously known range in northwestern Québec. Despite extensive searches, the species was not found north of 52°05'N. The Mink Frog (Lithobates septentrionalis) was widespread and relatively common in Québec, but was sought but not found in Ontario. The Leopard Frog (Lithobates pipiens) was only found at two Québec sites, including one where it was reported in 1974, but it has not been found at any of the Ontario sites where it was found in the 1970's. We present some suggestions for the further study of the herpetofauna of the area, and review evidence for contacts between eastern and western lineages of widespread species.En mai et juin 2002, dans le cadre d'un inventaire faunique dans la région de la baie James, en Ontario et au Québec, nous avons inventorié la faune herpétologique, laquelle est très peu documentée dans cette région. En Ontario nous avons visité des sites près de Moosonee, que l'un de nous (FWS) avait inventorié en 1971-1972, puis nous sommes allés aux environs de Cochrane. Au Québec l'inventaire s'est majoritairement fait le long de la route de la baie James et des routes d'accès aux villages. Le Crapaud d'Amérique (Anaxyrus americanus), la Rainette crucifère (Pseudacris crucifer) et la Grenouille des bois (Lithobates sylvaticus) sont répandus et communs sur toute l'aire d'étude. La Salamandre à points bleus (Ambystoma laterale) et la Couleuvre rayée (Thamnophis sirtalis) sont répandues et communes au Québec et près de Cochrane. Nous avons réalisé les premiers enregistrements de chants et collecté le premier spécimen de Rainette faux-grillon boréale (Pseudacris maculata) pour le Québec, et n'avons pu la retrouver à Moosonee et à son aéroport, où l'espèce avait été recensée en 1972. La seule extension d'aire significative a été faite pour la Salamandre à deux lignes (Eurycea bislineata), trouvée à 200 km au nord de son aire de répartition connue dans le nord-ouest du Québec. Malgré des recherches intensives, elle n'a pas été vue plus au nord que 52°05'N. La Grenouille du Nord (Lithobates septentrionalis), est répandue et relativement commune au Québec mais n'a pu être trouvée en Ontario. La Grenouille léopard (Lithobates pipiens) a seulement été recensée à deux endroits au Québec, incluant un site où l'espèce avait été trouvée en 1974, mais n'a pu être trouvée en Ontario dans les sites où on la retrouvait dans les années '70. Nous présentons quelques suggestions de futures études sur l'herpétofaune de cette région, et discutons des liens entre les formes de l'ouest et celles de l'est pour les espèces répandues

    Genetic determinants of gut microbiota composition and bile acid profiles in mice.

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    The microbial communities that inhabit the distal gut of humans and other mammals exhibit large inter-individual variation. While host genetics is a known factor that influences gut microbiota composition, the mechanisms underlying this variation remain largely unknown. Bile acids (BAs) are hormones that are produced by the host and chemically modified by gut bacteria. BAs serve as environmental cues and nutrients to microbes, but they can also have antibacterial effects. We hypothesized that host genetic variation in BA metabolism and homeostasis influence gut microbiota composition. To address this, we used the Diversity Outbred (DO) stock, a population of genetically distinct mice derived from eight founder strains. We characterized the fecal microbiota composition and plasma and cecal BA profiles from 400 DO mice maintained on a high-fat high-sucrose diet for ~22 weeks. Using quantitative trait locus (QTL) analysis, we identified several genomic regions associated with variations in both bacterial and BA profiles. Notably, we found overlapping QTL for Turicibacter sp. and plasma cholic acid, which mapped to a locus containing the gene for the ileal bile acid transporter, Slc10a2. Mediation analysis and subsequent follow-up validation experiments suggest that differences in Slc10a2 gene expression associated with the different strains influences levels of both traits and revealed novel interactions between Turicibacter and BAs. This work illustrates how systems genetics can be utilized to generate testable hypotheses and provide insight into host-microbe interactions

    Taxonomy based on science is necessary for global conservation

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    Peer reviewe

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    Apparent widespread decline of the Boreal Chorus Frog (Pseudacris maculata) in eastern Ottawa

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    The Boreal Chorus Frog (Pseudacris maculata) was once common in the eastern Ottawa area. To assess its current status, we conducted auditory surveys at 184 wetlands in 2011 and 2012. Boreal Chorus Frogs were heard at only five (2.7%) of the surveyed sites. These five sites were spatially aggregated, with only 0.5–7.5 km between any two sites. Sites occupied by Boreal Chorus Frogs in eastern Ottawa were surrounded by significantly greater agricultural cover (at 1.0-, 1.5-, and 2.0-km radii), less forest cover (1.0- and 2.0-km radii), and less wetland cover (1.5- and 2.0-km radii) than occupied sites in western Ottawa. Sites in eastern Ottawa that were apparently unoccupied were surrounded by significantly greater agricultural cover (only at the 2.0-km radius), similar forest cover (all radii), and less wetland cover (all radii) compared with occupied sites in western Ottawa. Boreal Chorus Frog populations are commonly subject to extirpation resulting from stochastic events. The reduced wetland cover in eastern Ottawa may be accompanied by reduced wetland connectivity, making recolonization of wetlands difficult or impossible. Our data do not show whether wetland connectivity has been reduced, but future research should address this important topic

    Apparent widespread decline of the Boreal Chorus Frog (<em>Pseudacris maculata</em>) in eastern Ottawa

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    The Boreal Chorus Frog (Pseudacris maculata) was once common in the eastern Ottawa area. To assess its current status, we conducted auditory surveys at 184 wetlands in 2011 and 2012. Boreal Chorus Frogs were heard at only five (2.7%) of the surveyed sites. These five sites were spatially aggregated, with only 0.5–7.5 km between any two sites. Sites occupied by Boreal Chorus Frogs in eastern Ottawa were surrounded by significantly greater agricultural cover (at 1.0-, 1.5-, and 2.0-km radii), less forest cover (1.0- and 2.0-km radii), and less wetland cover (1.5- and 2.0-km radii) than occupied sites in western Ottawa. Sites in eastern Ottawa that were apparently unoccupied were surrounded by significantly greater agricultural cover (only at the 2.0-km radius), similar forest cover (all radii), and less wetland cover (all radii) compared with occupied sites in western Ottawa. Boreal Chorus Frog populations are commonly subject to extirpation resulting from stochastic events. The reduced wetland cover in eastern Ottawa may be accompanied by reduced wetland connectivity, making recolonization of wetlands difficult or impossible. Our data do not show whether wetland connectivity has been reduced, but future research should address this important topic

    Long-Distance fencepost Sandpipers

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    An Analysis Of Selection On A Colour Polymorphism In The Northern Leopard Frog

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    In this study, we investigated the role of selection in the maintenance of a dorsal colour polymorphism in natural populations of the northern leopard frog, Rana pipiens. We determined genetic structure both spatially and temporally from a suite of putatively neutral molecular markers and tested whether or not the colour locus exhibited patterns of genetic variation that differed from those of the neutral loci. Spatial genetic structure at the colour locus was indistinguishable from structure at neutral loci [95% confidence intervals of FST (neutral) = (0.07, 0.35), FST (colour locus) = 0.114]. In the temporal analysis, we found that the variance among populations in the change in allele frequency at the colour locus (equal to 0.004) lies within the 95% confidence intervals for the variance among populations in changes in allele frequencies at neutral loci. In light of our inability to show evidence for the selective maintenance of the colour polymorphism, we used computer simulations to infer the power of our spatial and temporal techniques to detect selection. The computer simulations showed that although the strength of selection (s) would need to be relatively strong to have been detected by the temporal approach (s = 0.1-0.4, depending on the model tested), the spatial analysis would have detected all but weak selection (s = 0.01-0.04, depending on the model tested). This study illustrates the importance of using a locus comparison approach to detect evidence for selective maintenance before conducting studies to measure the selective mechanisms maintaining a polymorphism. © 2006 The Authors
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