251 research outputs found
Potential of Salvinia biloba Raddi for removing atrazine and carbendazim from aquatic environments
Abstract:
In this exploratory study, naturally occurring Salvinia biloba Raddi specimens were assessed for atrazine and carbendazim
polluted water remediation. Experiments were carried out over 21 days in glass vessels containing deionized water artifcially
contaminated with 0, 5, 10, and 20 mg Lâ1 of atrazine or carbendazim. Atrazine had a pronounced detrimental impact on
S. biloba, as no biomass development was observed in all macrophytes exposed to this herbicide in the entire concentration
range. However, carbendazim-treated plants were able to grow and survive in the polluted medium even when subjected to
the highest concentration of this fungicide (i.e., 20 mg Lâ1). In addition, increased chlorosis and necrosis were also detected
in plants subjected to carbendazim as a result of the high phytotoxicity caused by atrazine. A maximal removal efciency
of~30% was observed for both pesticides at 5 mg Lâ1 and decreased with increasing concentrations of the pollutants. The
spectrum of the FTIR-ATR analysis revealed the existence of various functional groups (e.g., amide, carboxyl, hydroxyl,
phosphate, sulfate) on the plants, which could be related to pesticide biosorption. In addition, at the end of the 21-day
assay, seven carbendazim-resistant bacteria could be isolated from the roots of fungicide-treated plants. Therefore, the use
of autochthonous free-foating S. biloba macrophytes for phytoremediation of aquatic environments contaminated with
carbendazim shows great promise. Still, additional research is required to further elucidate the plant-mediated carbendazim
elimination process and the role of the herbicide-resistant bacteria, and seek alternative species capable of mitigating atrazine
contamination
Experimental evidence of contamination on the dynamics of shrimp populations: susceptibility to spatial isolation
Landscape-scale ecology comprises complex structures where a flow of energy, materials and organisms among ecosystems conditions the dynamics of populations. Several natural and anthropogenic stressors are likely to affect the landscape composition, generally leading to the rupture of ecological connectivity among populations. Although contamination is considered one of the most threatening factors for biodiversity, its impact on spatial dynamics of populations (e.g., distribution, persistence and abundance) from an eco-toxicological perspective is still unknown. In the current study, the potential effect that contamination can exert on the loss of connectivity among populations (chemically fragmented habitats) leading to population isolation was assessed. The estuarine shrimp Palaemon varians was used as model organisms and a novel version of the HeMHAS (Heterogeneous Multi-Habitat Assay System) was used to simulate spatially heterogeneous landscapes. In order to provide more ecological relevance to the study, besides copper as stressor [at low (0.5 ÎŒg/L) and high (25 ÎŒg/L) levels], other two factors were simultaneously tested: fish kairomones (as a predation signal) and food availability. Different scenarios were simulated in the HeMHAS to create heterogeneous landscapes that vary depending on the presence or absence of these stressors. The behavior observed by the population of P. varians clearly showed that the shrimp detected copper and avoided the regions with the highest levels of contamination. However, when fish kairomones were added to previously preferred regions, the behavior of shrimp populations did a radical turn: they escape the predator signals, moving towards contaminated regions, but with a clear preference for less contaminated areas. When faced whether to stay in a clean area with no food or moving through disturbed regions to colonize a clean region with food, shrimpsâ populations crossed the regions, but with a more dynamic transit in the region with kairomones and no copper. These results indicate that contamination might interfere in the spatial dynamics of shrimpsâ populations by: (i) triggering avoidance, (ii) preventing colonization, (iii) isolating populations and (iv) making them more susceptible to local extinction
Experimental evidence of how contamination might modify the shrimpsâ population dynamics and make them susceptible to spatial isolation
Contamination is likely to affect the landscape composition, usually linked to ecological fragmentation, which may impact the distribution, persistence and abundance of species. In the current study, the estuarine shrimp Palaemon varians was exposed to copper (25 and 0.5 ÎŒg/L) simultaneously to predation signal and food to evaluate the organismâs spatial distribution within a spatially heterogeneous landscape. All experimental landscapes were simulated in the Heterogeneous Multi Habitat Assay System (HeMHAS). As results, P. varians detected and avoided copper, however, predation signal shifted the response to preference over regions with conditions previously avoided, even if that meant to increase copper exposure. When confronted to move towards environments with high food availability, lower connectivity occurred among the shrimpsâ populations isolated by contamination and predation risk simultaneously. This indicate that contamination might: (i) trigger avoidance in shrimps, (ii) prevent the colonisation towards foraging areas, (iii) enhance the populationsâ isolation and (iv) make populations more susceptible to local extinction
Muito tempo sem ver: ExpansĂŁo dos registros de Loxosceles amazonica (Araneae: Sicariidae) para o estado do Amazonas, Brasil
Spiders of the genus Loxosceles, commonly known as brown recluse spiders, can cause serious accidents in humans. Their venom has a powerful proteolytic and hemolytic action. Each year these spiders are the cause of a great number of araneism in Brazil. This work presents new records of Loxosceles amazonica for the municipal districts of Manaus and Iranduba, Amazonas, Brazil.As aranhas do gĂȘnero Loxosceles, conhecidas como aranhas marrons, podem causar sĂ©rios acidentes em humanos. O veneno destas aranhas possui potente ação proteolĂtica e hemolĂtica. A cada ano estas aranhas sĂŁo responsĂĄveis pelo maior nĂșmero de araneĂsmos no Brasil. Este trabalho apresenta novos registros de Loxosceles amazonica para o estado do Amazonas, Brasil
The kSORT Assay to Detect Renal Transplant Patients at High Risk for Acute Rejection: Results of the Multicenter AART Study
Development of noninvasive molecular assays to improve disease diagnosis and patient monitoring is a critical need. In renal transplantation, acute rejection (AR) increases the risk for chronic graft injury and failure. Noninvasive diagnostic assays to improve current late and nonspecific diagnosis of rejection are needed. We sought to develop a test using a simple blood gene expression assay to detect patients at high risk for AR. We developed a novel correlation-based algorithm by step-wise analysis of gene expression data in 558 blood samples from 436 renal transplant patients collected across eight transplant centers in the US, Mexico, and Spain between 5 February 2005 and 15 December 2012 in the Assessment of Acute Rejection in Renal Transplantation (AART) study. Gene expression was assessed by quantitative real-time PCR (QPCR) in one center. A 17-gene setâthe Kidney Solid Organ Response Test (kSORT)âwas selected in 143 samples for AR classification using discriminant analysis (area under the receiver operating characteristic curve [AUC]â=â0.94; 95% CI 0.91â0.98), validated in 124 independent samples (AUCâ=â0.95; 95% CI 0.88â1.0) and evaluated for AR prediction in 191 serial samples, where it predicted AR up to 3 mo prior to detection by the current gold standard (biopsy). A novel reference-based algorithm (using 13 12-gene models) was developed in 100 independent samples to provide a numerical AR risk score, to classify patients as high risk versus low risk for AR. kSORT was able to detect AR in blood independent of age, time post-transplantation, and sample source without additional data normalization; AUCâ=â0.93 (95% CI 0.86â0.99). Further validation of kSORT is planned in prospective clinical observational and interventional trials. The kSORT blood QPCR assay is a noninvasive tool to detect high risk of AR of renal transplants
A Peripheral Blood Diagnostic Test for Acute Rejection in Renal Transplantation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93759/1/j.1600-6143.2012.04253.x.pd
Promised Land? Immigration, Religiosity, and Space in Southern California
This article looks at how immigrants and their supporters appropriate and use religious space and other public spaces for religious and socio-political purposes in Southern California. While the everyday living conditions of many immigrants, particularly the unauthorized Latino immigrants, force unto them an embodied disciplinarity that maintains spatialities of restricted citizenship, the public appropriations of space for and through religious practices allow for them -even if only momentarily -to express an embodied transgression. This practice in public space helps realize spaces of freedom and hope, however ephemerally. Potentially, these rehearsing exercises can help revert internalized disempowering subjectivities and create social empowerment. Negative stereotypes about immigrants held by the larger public can also be challenged through these spatial practices, as the public demonstrations make visible the invisible. We focus on âPosadas Without Bordersâ and âthe New Sanctuary Movement,â considering both the role of progressive civic and religious institutions in supporting immigrants and the agency of the immigrants themselves. The theoretical analysis builds on concepts drawn from a conversation between geography and religious and theological studies. We use a triangulated methodological approach that includes observation and participant observation, content-analysis of multimedia, interviews, and intellectual advocacy for the immigrant movement. The cases discussed here show that progressive religious groups and coalitions can be important allies to progressive planners, geographers, and policy makers in advancing social and environmental justice for the disenfranchised. They also show that the theological underpinnings of such groups share a lot in common with planning epistemologies for the just city
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