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31.
Astrid V. Stronen Graham J. Forbes Paul C. Paquet Gloria Goulet Tim Sallows Marco Musiani 《Conservation Genetics》2012,13(2):359-371
The effects of human-caused fragmentation require further study in landscapes where physical dispersal barriers and natural
ecological transitions can be discounted as causes for population genetic structure. We predict that fragmentation can reduce
dispersal across such barrier-free landscapes because dispersal also is limited by a perception of risk. Considerable fragmentation
has occurred in the Riding Mountain National Park (RMNP) region in Manitoba, Canada, during the past 60 years. We examine
data from 13 autosomal microsatellites to determine whether fragmentation is correlated with genetic population structure
in wolves (Canis lupus). Moderate and significant differentiation between RMNP and a genetic cluster identified 30 km farther north (F
ST = 0.053, 95% CI [0.031–0.073]) is consistent with predicted effects of fragmentation. The RMNP population cluster represents
at least seven wolf packs followed weekly by radio tracking during 2003–2006. Distinct mtDNA haplotypes have been identified
in the Park and no successful wolf dispersal from RMNP has been documented in several multi-year tracking studies since 1974.
Tracking data also indicate that some wolves might be reluctant to leave RMNP. Although the influence of behaviour and local
adaptation require investigation, human-caused fragmentation appears to have caused cryptic genetic structure on fine spatiotemporal
scales in a vagile species that is: (1) not influenced by physical movement barriers or historical ecological discontinuities
in our study area, and; (2) able to live relatively close to humans. The Great Plains is now an intensely human-managed landscape.
Detection of cryptic genetic structure could therefore function as an important indicator in conservation management. 相似文献
32.
Implementation of ecosystem-based fisheries management (EBFM) requires a clear conceptual and quantitative framework for assessing how different harvest options can modify benefits to ecosystem and human beneficiaries. We address this social-ecological need for Pacific salmon fisheries, which are economically valuable but intercept much of the annual pulse of nutrient subsidies that salmon provide to terrestrial and aquatic food webs. We used grizzly bears, vectors of salmon nutrients and animals with densities strongly coupled to salmon abundance, as surrogates for "salmon ecosystem" function. Combining salmon biomass and stock-recruitment data with stable isotope analysis, we assess potential tradeoffs between fishery yields and bear population densities for six sockeye salmon stocks in Bristol Bay, Alaska, and British Columbia (BC), Canada. For the coastal stocks, we find that both bear densities and fishery yields would increase substantially if ecosystem allocations of salmon increase from currently applied lower to upper goals and beyond. This aligning of benefits comes at a potential cost, however, with the possibility of forgoing harvests in low productivity years. In contrast, we detect acute tradeoffs between bear densities and fishery yields in interior stocks within the Fraser River, BC, where biomass from other salmon species is low. There, increasing salmon allocations to ecosystems would benefit threatened bear populations at the cost of reduced long-term yields. To resolve this conflict, we propose an EBFM goal that values fisheries and bears (and by extension, the ecosystem) equally. At such targets, ecosystem benefits are unexpectedly large compared with losses in fishery yields. To explore other management options, we generate tradeoff curves that provide stock-specific accounting of the expected loss to fishers and gain to bears as more salmon escape the fishery. Our approach, modified to suit multiple scenarios, provides a generalizable method to resolve conflicts over shared resources in other systems. 相似文献
33.
C. T. Darimont P. C. Paquet T. E. Reimchen V. Crichton 《Diversity & distributions》2005,11(3):235-239
Ranges of species are dynamic and respond to long‐term climate change and contemporary effects such as habitat modification. We report here that moose (Alces alces) have recently colonized coastal temperate rainforests of British Columbia, Canada. Contrary to recent publications, field observations of moose and their sign, combined with their occurrence in wolf (Canis lupus) faeces, suggest that moose are now widespread on the coastal mainland and occur on least three islands. Traditional ecological knowledge (information accumulated by aboriginal peoples about their environment) suggests that colonization occurred during the mid 1900s, concomitant with logging of major watersheds that bisect the Coast Mountain Range. Range expansion by moose may have ecological consequences such as alteration of predator–prey dynamics and transmission of disease to native deer (Odocoileus hemionus). 相似文献
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Sylvie Rocheleau Ruxandra Cimpoia Louise Paquet Iris van Koppen Serge R. Guiot Jalal Hawari Guy Ampleman Sonia Thiboutot Geoffrey I. Sunahara 《Bioremediation Journal》1999,3(3):233-246
The ecotoxicological effects of four bioslurry reactors treating 2,4,6-trinitotoluene (TNT)- and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX)-spiked soil were evaluated. A control bioslurry reactor was used to assess the endogenous toxicity of the bioslurry operation conditions. A battery of ecotoxicity tests was used: Microtox, green algae growth inhibition, bacterial genotoxicity and mutagenicity, and earthworm mortality and growth inhibition. Bioslurry soluble and solid phases were separated by centrifugation in order to identify toxicity and possible toxicants associated with each phase. Microtox toxicity values were initially very high in both bioslurry reactors spiked with TNT, in relation with TNT concentration. Initial toxicity was also detected by algal growth inhibition, earthworm lethality, genotoxicity and mutagenicity tests. An endogenous toxicity was detected in the control bioreactor using the Microtox and the SOS Chromotest. The soluble phase of the control bioslurry was genotoxic, suggesting that some potentially genotoxic agents were induced in the bioslurry samples. At the end of the bioremediation treatment, data showed that toxicity was reduced using all of the bioassays, except for earthworm lethality and growth inhibition tests in both RDX-spiked bioslurries. This study demonstrates the usefulness of a battery of toxicity tests to monitor bioremediation processes. 相似文献
36.
Biotransformation of 2,4,6-Trinitrotoluene with Phanerochaete chrysosporium in Agitated Cultures at pH 4.5 下载免费PDF全文
Jalal Hawari Annamaria Halasz Sylvie Beaudet Louise Paquet Guy Ampleman Sonia Thiboutot 《Applied microbiology》1999,65(7):2977-2986
The biotransformation of 2,4,6-trinitrotoluene (TNT) (175 μM) by Phanerochaete chrysosporium with molasses and citric acid at pH 4.5 was studied. In less than 2 weeks, TNT disappeared completely, but mineralization (liberated 14CO2) did not exceed 1%. A time study revealed the presence of several intermediates, marked by the initial formation of two monohydroxylaminodinitrotoluenes (2- and 4-HADNT) followed by their successive transformation to several other products, including monoaminodinitrotoluenes (ADNT). A group of nine acylated intermediates were also detected. They included 2-N-acetylamido-4,6-dinitrotoluene and its p isomer, 2-formylamido-4,6-dinitrotoluene and its p isomer (as acylated ADNT), 4-N-acetylamino-2-amino-6-nitrotoluene and 4-N-formylamido-2-amino-6-nitrotoluene (as acetylated DANT), 4-N-acetylhydroxy-2,6-dinitrotoluene and 4-N-acetoxy-2,6-dinitrotoluene (as acetylated HADNT), and finally 4-N-acetylamido-2-hydroxylamino-6-nitrotoluene. Furthermore, a fraction of HADNTs were found to rearrange to their corresponding phenolamines (Bamberger rearrangement), while another group dimerized to azoxytoluenes which in turn transformed to azo compounds and eventually to the corresponding hydrazo derivatives. After 30 days, all of these metabolites, except traces of 4-ADNT and the hydrazo derivatives, disappeared, but mineralization did not exceed 10% even after the incubation period was increased to 120 days. The biotransformation of TNT was accompanied by the appearance of manganese peroxidase (MnP) and lignin-dependent peroxidase (LiP) activities. MnP activity was observed almost immediately after TNT disappearance, which was the period marked by the appearance of the initial metabolites (HADNT and ADNT), whereas the LiP activity was observed after 8 days of incubation, corresponding to the appearance of the acyl derivatives. Both MnP and LiP activities reached their maximum levels (100 and 10 U/liter, respectively) within 10 to 15 days after inoculation. 相似文献
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Marylène Fortin Hélène D'Anjou Marie-ève Higgins Jasmine Gougeon Paméla Aubé Kamel Moktefi Sonia Mouissi Serge Séguin Rosanne Séguin Paolo M Renzi Luc Paquet Nicolay Ferrari 《Respiratory research》2009,10(1):39
Background
Recent development in the field of COPD has focused on strategies aimed at reducing the underlying inflammation through selective inhibition of the phosphodiesterase type IV (PDE4) isoform. Although the anti-inflammatory and bronchodilator activity of selective PDE4 inhibitors has been well documented, their low therapeutic ratio and dose-dependent systemic side effects have limited their clinical utility. This study examined the effect of 2''-deoxy-2''-Fluoro-β-D-Arabinonucleic Acid (FANA)-containing antisense oligonucleotides (AON) targeting the mRNA for the PDE4B/4D and 7A subtypes on lung inflammatory markers, both in vitro and in vivo.Methods
Normal human bronchial epithelial (NHBE) cells were transfected with FANA AON against PDE4B/4D and 7A alone or in combination. mRNA levels for target PDE subtypes, as well as secretion of pro-inflammatory chemokines were then measured following cell stimulation. Mice were treated with combined PDE4B/4D and 7A AON via endo-tracheal delivery, or with roflumilast via oral delivery, and exposed to cigarette smoke for one week. Target mRNA inhibition, as well as influx of inflammatory cells and mediators were measured in lung lavages. A two-week smoke exposure protocol was also used to test the longer term potency of PDE4B/4D and 7A AONs.Results
In NHBE cells, PDE4B/4D and 7A AONs dose-dependently and specifically inhibited expression of their respective target mRNA. When used in combination, PDE4B/4D and 7A AONs significantly abrogated the cytokine-induced secretion of IL-8 and MCP-1 to near baseline levels. In mice treated with combined PDE4B/4D and 7A AONs and exposed to cigarette smoke, significant protection against the smoke-induced recruitment of neutrophils and production of KC and pro-MMP-9 was obtained, which was correlated with inhibition of target mRNA in cells from lung lavages. In this model, PDE AONs exerted more potent and broader anti-inflammatory effects against smoke-induced lung inflammation than roflumilast. Moreover, the protective effect of PDE4B/4D and 7A AON was maintained when a once-weekly treatment schedule was used.Conclusion
These results indicate that inhaled AON against PDE4B/4D and 7A have unique effects on biomarkers that are believed to be important in the pathophysiology of COPD, which supports further development as a potential therapy in this disease. 相似文献40.
Laura V. Croft Nicholas W. Ashton Nicolas Paquet Emma Bolderson Kenneth J. O’Byrne Derek J. Richard 《BMC molecular biology》2017,18(1):13