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Dias F.B.S.,French National Center for Scientific Research | Quartier M.,French National Center for Scientific Research | Quartier M.,University of Neuchatel | Mejia G.,Simón Bolívar University of Colombia | And 6 more authors.
Parasites and Vectors | Year: 2014

Background: The rising number of acute cases of Chagas disease in the State of Pará, reported in the past two decades, has been associated, in part, with the ingestion of juice of local palm tree fruits, mainly açaí berry and bacaba. Near the study area, in Santarém, Pará State, an outbreak of Chagas disease has been notified and investigations suggest the consumption of bacaba juice as the main source of infection with T. cruzi. The purpose of this study is to assess the aspects associated to the ecology of Rhodnius robustus in palm trees of three communities of the Tapajós region, in the State of Pará, Brazil. Methods. Palm trees were cut down and dissected to search for triatomines. DNA from triatomines was extracted to investigate natural infection by Trypanosoma cruzi and T. rangeli. For statistical analyzes, data from infestation of palm trees, as well as the rates of natural infection by T. cruzi and T. rangeli were compared by Chi-square test. Triatomine density values were analyzed by the nonparametric Kruskal Wallis test and then comparisons between each pair of variables were made by the Mann-Whitney test assuming a confidence interval of 95%. Results: We dissected 136 palm trees, 60 at the end of the rainy period and 76 at the end of the dry period. Seventy-three of them (53.7%) were infested with triatomines and three species were found, namely: Rhodnius robustus, Rhodnius pictipes and Panstrongylus lignarius. We collected 743 triatomines, and R. robustus was predominant (n = 739). The identification of natural infection of the insects by trypanosomatids revealed that 125 triatomines were infected by T. cruzi, 69 by T. rangeli and 14 presented both parasites, indicating the presence of mixed infection in the same vector. Conclusion: The results suggest that São Tomé is the community with greater density of triatomines and infestation of palm trees; also, it demonstrates the existence of an intense sylvatic cycle in the region, which demands intensive surveillance to prevent human transmission. © 2014 Dias et al.; licensee BioMed Central Ltd.

PubMed | University of Oregon, Northeastern University and Biodome de Montreal
Type: Journal Article | Journal: Developmental dynamics : an official publication of the American Association of Anatomists | Year: 2016

Environmental temperature influences rates of embryonic development, but a detailed staging series for vertebrate embryos developing in the subzero cold of Antarctic waters is not yet available from fertilization to hatching. Given projected warming of the Southern Ocean, it is imperative to establish a baseline to evaluate potential effects of changing climate on fish developmental dynamics.We studied the Bullhead notothen (Notothenia coriiceps), a notothenioid fish inhabiting waters between -1.9 and +2C. In vitro fertilization produced embryos that progressed through cleavage, epiboly, gastrulation, segmentation, organogenesis, and hatching. We compared morphogenesis spatially and temporally to Zebrafish and medaka. Experimental animals hatched after about 6 months to early larval stages. To help understand skeletogenesis, we analyzed late embryos for expression of sox9 and runx2, which regulate chondrogenesis, osteogenesis, and eye development. Results revealed that, despite their prolonged developmental time course, N. coriiceps embryos developed similarly to those of other teleosts with large yolk cells.Our studies set the stage for future molecular analyses of development in these extremophile fish. Results provide a foundation for understanding the impact of ocean warming on embryonic development and larval recruitment of notothenioid fish, which are key factors in the marine trophic system. Developmental Dynamics 245:1066-1080, 2016. 2016 Wiley Periodicals, Inc.

Tremblay S.,University of Quebec at Montréal | Lucotte M.,University of Quebec at Montréal | Reveret J.-P.,University of Quebec at Montréal | Davidson R.,Biodome de Montreal | And 3 more authors.
Agroforestry Systems | Year: 2015

Agroforestry systems are widely recognized as an important way to address numerous environmental challenges in tropical areas. They represent a sustainable alternative form of land-use for small-scale agriculture, responding to the economic development needs of communities and offering a number of ecosystem services. This article presents an evaluation of the short- and medium-term profitability of two experimental agroforestry systems where fruit trees are predominant, which were established in 2009 in the Tapajós region of the Brazilian Amazon, state of Pará. An analysis of net present value (NPV) confirms that the two experimental systems studied recover their total implementation and operating costs within a 20 years time horizon. These results underlie that prices of inputs are stable and farmers have access to markets, credit, and agricultural knowledge. The two experimental systems are compared to plots under traditional slash-and-burn cultivation, and Bragantino system. The results support changes to public policies in order to facilitate alternatives to slash-and-burn cultivation by supporting access to credit, knowledge of alternative agricultural practices, transportation systems, and industries that transform agricultural products. The consideration of ecosystem services should add a supplementary argument in favour of policies that promote agroforestry systems and thus limit the practice of slash-and-burn subsistence agriculture. © 2014, Springer Science+Business Media Dordrecht.

Beliveau A.,University of Quebec at Montréal | Davidson R.,University of Quebec at Montréal | Lucotte M.,University of Quebec at Montréal | Do Canto Lopes L.O.,Federal University of Pará | And 2 more authors.
Journal of Agricultural Science | Year: 2015

Increasing human occupation of the Brazilian Amazon has led to the intensification of deforestation over the last 50 years. The present study is aimed at analysing the impacts of the first year of slash-and-burn cultivation on soil physicochemical properties. Sampling was done in 26 small-scale farms of the Tapajós River basin. In August 2004, soil samples were collected from primary forest plots planned for slash-and-burn cultivation. In September 2005, 1 year after the initial burning and the beginning of cultivation, the same sites were re-sampled. The results indicated that soil fertility after burning was relatively moderate, as the increase of base cations was not particularly marked. Moreover, although an increase of some nutrients (such as exchangeable phosphorus) was observed at soil surface, total carbon and nitrogen (N) pools did not change significantly. Nutrient leaching was also detected through the accumulation of both forms of available nitrogen (NO3 and NH4) as well as potassium in subsoil horizons. In addition, signs of erosion were seen, as a significant increase surface density occurred, coupled with up to 25% fine particle loss at the surface. The present study draws attention to the early impacts of slash-and-burn agriculture on soil properties within a year of cultivation. Furthermore, its regional dimension highlights undisturbed soils natural variability as well as differentiated responses to deforestation according to soil texture. © Cambridge University Press 2014.

Comte I.,University of Quebec at Montréal | Lucotte M.,University of Quebec at Montréal | Davidson R.,Biodome de Montreal | Davidson R.,University of Quebec at Montréal | And 3 more authors.
Water, Air, and Soil Pollution | Year: 2013

Many studies have shown the relationship between fire clearing and mercury contamination of aquatic ecosystems in the Brazilian Amazon. This study aimed at quantifying mercury content in long-time cultivated soils and at assessing the potential of a fire-free alternative clearing technique on mercury retention for long-time cultivated soils compared to traditional slash-and-burn. This case study included five land uses: one crop plot and one pasture plot cleared using slash-and-burn, one crop plot and one pasture plot cleared using chop-and-mulch, and one 40-year-old forest as a control. Low mercury concentrations were recorded in the surface horizon (24.83 to 49.48 ng g-1, 0-5 cm depth). The long-time cultivation (repeated burnings) of these soils triggered large mercury losses in the surface horizon, highlighted by high enrichment factors from surface to deeper horizons. The predominant effect of repeated burnings before the experimental implementation did not let us to distinguish a positive effect of the chop-and-mulch clearing method on soil mercury retention for crops and pastures. Moreover, some processes related to the presence of the mulch may favor mercury retention (Hg volatilization decrease, cationic sites increase), while others may contribute to mercury losses (cationic competition and dislocation, mobilization by the dissolved organic matter). © 2013 Springer Science+Business Media Dordrecht.

Comte I.,University of Quebec at Montréal | Davidson R.,Biodome de Montreal | Davidson R.,University of Quebec at Montréal | Lucotte M.,University of Quebec at Montréal | And 4 more authors.
Agriculture, Ecosystems and Environment | Year: 2012

Over a century, subsistence agriculture has been practiced in the Brazilian Amazon, using slash-and-burn as a traditional land clearing technique. However, fire clearing leads to nutrient losses, and the increasing demographic pressure reduces the duration of the fallow period, threatening the system sustainability. The chop-and-mulch land clearing method, combined or not with legume-enriched fallow, is a promising alternative technique as the retention of organic residues upon land clearance of fallow could promote soil fertility. The aim of this study is to assess the effect of fire-free land preparation on soil physicochemical properties by comparing the effects of traditional slash-and-burn with (i) chop-and mulch with enriched fallow in croplands and (ii) chop-and-mulch without enriched fallow in pastures. The chop-and-mulch of a legume-enriched fallow conserved soil bulk density, and significantly increased nutrient concentrations and organic matter content compared to the burnt cropland and the control forest. In the pastures, the use of chop-and-mulch of a non-enriched fallow had less impact on soil physical and chemical properties, excepted on water retention capacity and total P stock. Land clearing of fallows by chop-and-mulch, especially when enriched with legumes could significantly improve agriculture sustainability in the region and reduce the pressure on primary forests. © 2012 Elsevier B.V..

Auclair J.,INRS Institute Armand Frappier | Parent S.,Biodome de Montreal | Villemur R.,INRS Institute Armand Frappier
Microbial Ecology | Year: 2012

Nitrate is a serious problem in closed-circuit public aquariums because its accumulation rapidly becomes toxic to many lifeforms. A moving bed biofilm denitrification reactor was installed at the Montreal Biodome to treat its 3,250-m3 seawater system. Naturally occurring microorganisms from the seawater affluent colonized the reactor carriers to form a denitrifying biofilm. Here, we investigated the functional diversity of this biofilm by retrieving gene sequences related to narG, napA, nirK, nirS, cnorB, and nosZ. A total of 25 sequences related to these genes were retrieved from the biofilm. Among them, the corresponding napA1, nirK1, cnorB9, and nosZ3 sequences were identical to the corresponding genes found in Hyphomicrobium sp. NL23 while the narG1 and narG2 sequences were identical to the two corresponding narG genes found in Methylophaga sp. JAM1. These two bacterial strains were previously isolated from the denitrifying biofilm. To assess the abundance of denitrifiers and nitrate respirers in the biofilm, the gene copy number of all the narG, napA, nirS, and nirK sequences found in biofilm was determined by quantitative PCR. napA1, nirK1, narG1, and narG2, which were all associated with either Methylophaga sp. JAM1 or Hyphomicrobium sp. NL23, were the most abundant genes. The other genes were 10 to 10,000 times less abundant. nirK, cnorB, and nosZ but not napA transcripts from Hyphomicrobium sp. NL23 were detected in the biofilm, and only the narG1 transcripts from Methylophaga sp. JAM1 were detected in the biofilm. Among the 19 other genes, the transcripts of only two genes were detected in the biofilm. Our results show the predominance of Methylophaga sp. JAM1 and Hyphomicrobium sp. NL23 among the denitrifiers detected in the biofilm. The results suggest that Hyphomicrobium sp. NL23 could use the nitrite present in the biofilm generated by nitrate respirers such as Methylophaga sp. JAM1. © 2011 Springer Science+Business Media, LLC.

Fabianek F.,University of Quebec at Montréal | Gagnon D.,University of Quebec at Montréal | Delorme M.,Biodome de Montreal
Ecoscience | Year: 2011

In Quebec, Canada, 5 out of the 8 species of bats are considered potentially threatened or vulnerable. Measuring the impact on bat species of environmental changes brought about by urban development is crucial for bat species conservation. At which spatial scale does a gradient of increasing urbanization have the most significant effect on the distribution and activity of bats? To address this question, 3 sampling points in each of 24 green spaces (of different sizes, degree of naturalness, and presence or not of water) across Montréal Island were sampled over 3 separate nights in June and July 2006. Echolocation calls of bats were recorded with Anabat detectors. Bat activity was determined by species or group of species for each green space. Various habitat factors associated with the urban gradient were acquired using GIS along a range of spatial scales, from local to landscape scales (areas of 0.1 km to 2 km radius around sampling points). Results show that patterns of distribution and bat activity differ according to species. Bats of the Myotis genus and Perimyotis subflavus were found mostly in areas with a high percentage of forest cover and near running water. Eptesicus fuscus and Lasiurus cinereus appeared to be less selective, as they were distributed much more uniformly across the study area. The more local spatial scales (from 0.1 km to 0.5 km radius) seem to have had a predominant influence on habitat requirements of bats, particularly for forest-dwelling species.

Auclair J.,INRS Institute Armand Frappier | Lepine F.,INRS Institute Armand Frappier | Parent S.,Biodome de Montreal | Villemur R.,INRS Institute Armand Frappier
ISME Journal | Year: 2010

Methylophaga spp. are methylotrophs commonly associated with marine environments and have been defined as strict aerobic methylotrophs. They have been shown previously to represent 50-70% of the bacterial population in the biofilm of the methanol-fed denitrification reactor treating a large seawater aquarium at the Montreal Biodome. It was therefore surprising to find such a high concentration of Methylophaga spp. in anoxic conditions. In this study, we showed by cultivation-independent and -dependent approaches that one Methylophaga strain present in the anoxic biofilm is involved in the denitrification process. DNA stable-isotope probing (SIP) experiments in which the biofilm was cultured under denitrifying conditions with 13C- methanol have revealed the enrichment of one particular taxon. By screening a 16S ribosomal RNA gene library derived from a 13C-DNA fraction of the SIP gradients, 62% of the library was composed of one sequence affiliated with the genus Methylophaga. One strain, named JAM1, representing this Methylophaga species was isolated. It grows aerobically but also under denitrifying conditions by reducing nitrate into nitrite. The nitrate-reducing activity was correlated with the presence and the expression of two highly divergent narG genes (narG1 and narG2). narG1 showed a high percentage of identity with the corresponding part of narG found in Thiobacillus denitrificans, which suggests a recent acquisition of narG in strain JAM1 by horizontal gene transfer. This study provides the first direct evidence of the adaptation of a Methylophaga species to an oxygen-limited environment. © 2010 International Society for Microbial Ecology. All rights reserved.

PubMed | University of Quebec at Montréal, University of Brasilia and Biodome de Montreal
Type: Journal Article | Journal: Archives of environmental contamination and toxicology | Year: 2016

In the Tapajs River region of the Brazilian Amazon, mercury (Hg) is a prevalent contaminant in the aquatic ecosystem. Few studies have used comprehensive chronological analyses to examine the combined effects of environmental and anthropogenic factors on Hg accumulation in sediments. Total mercury (THg) content was measured in sediments from eight floodplain lakes and

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