994 research outputs found

    Distribution of populations of broad-snouted caiman (Caiman latirostris, Daudin 1802, Alligatoridae) in the São Francisco River basin, Brazil

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    We surveyed populations of the broad-snouted caiman, Caiman latirostris, throughout the São Francisco River basin, from Três Marias reservoir, State of Minas Gerais, to the river delta, at the boarder of Sergipe and Alagoas states. We registered the occurrence of crocodilians in 61% of all surveyed localities (n = 64), in which the presence of C. latirostris was confirmed in 44% of the surveyed sites. Caimans occurred in both lentic and lotic habitats, although there was a preference for small dams, oxbow lakes and wetlands. Despite the hunting pressure and human impact on natural habitats, our results indicate that the populations of C. latirostris in the São Francisco basin are not fragmented

    The C-terminal region of Trypanosoma cruzi MASPs is antigenic and secreted via exovesicles.

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    Trypanosoma cruzi is the etiological agent of Chagas disease, a neglected and emerging tropical disease, endemic to South America and present in non-endemic regions due to human migration. The MASP multigene family is specific to T. cruzi, accounting for 6% of the parasite's genome and plays a key role in immune evasion. A common feature of MASPs is the presence of two conserved regions: an N-terminal region codifying for signal peptide and a C-terminal (C-term) region, which potentially acts as GPI-addition signal peptide. Our aim was the analysis of the presence of an immune response against the MASP C-term region. We found that this region is highly conserved, released via exovesicles (EVs) and has an associated immune response as revealed by epitope affinity mapping, IFA and inhibition of the complement lysis assays. We also demonstrate the presence of a fast IgM response in Balb/c mice infected with T. cruzi. Our results reveal the presence of non-canonical secreted peptides in EVs, which can subsequently be exposed to the immune system with a potential role in evading immune system targets in the parasite

    Effective Dark Matter Model: Relic density, CDMS II, Fermi LAT and LHC

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    The Cryogenic Dark Matter Search recently announced the observation of two signal events with a 77% confidence level. Although statistically inconclusive, it is nevertheless suggestive. In this work we present a model-independent analysis on the implication of a positive signal in dark matter scattering off nuclei. Assuming the interaction between (scalar, fermion or vector) dark matter and the standard model induced by unknown new physics at the scale Λ\Lambda, we examine various dimension-6 tree-level induced operators and constrain them using the current experimental data, e.g. the WMAP data of the relic abundance, CDMS II direct detection of the spin-independent scattering, and indirect detection data (Fermi LAT cosmic gamma-ray), etc. Finally, the LHC reach is also explored

    Geriatric oncology: comparing health related quality of life in head and neck cancer patients

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    Background: Population ageing is increasing the number of people annually diagnosed with cancer worldwide, once most types of tumours are age-dependent. High-quality healthcare in geriatric oncology requires a multimodal approach and should take into account stratified patient outcomes based on factors other than chronological age in order to develop interventions able to optimize oncology care. This study aims to evaluate the Health Related Quality of Life in head and neck cancer patients and compare the scores in geriatric and younger patients. Methods. Two hundred and eighty nine head and neck cancer patients from the Oncology Portuguese Institute participated in the Health Related Quality of Life assessment. Two patient groups were considered: the geriatric ( 65 years old, n = 115) and the younger (45-60 years old, n= 174). The EORTC QLQ-C30 and EORTC QLQ-H&N35 questionnaires were used. Results: Head and neck cancer patients were mostly males, 77.4% within geriatric group and 91.4% among younger patients group. The most frequent tumour locations were similar in both groups: larynx, oral cavity and oropharynx - base of the tongue. At the time of diagnosis, most of younger male patients were at disease stage III/IV (55.9%) whereas the majority of younger female patients were at disease stage I/II (83.4%). The geriatric patient distribution was found to be similar in any of the four disease stages and no gender differences were observed. We found that age (geriatrics scored generally worse), gender (females scored generally worse), and tumour site (larynx tumours denounce more significant problems between age groups) clearly influences Health Related Quality of Life perceptions. Conclusions: Geriatric oncology assessments signalize age-independent indicators that might guide oncologic geriatric care optimization. Decision-making in geriatric oncology must be based on tumour characteristics and chronological age but also on performance status evaluation, co-morbidity, and patient reported outcomes assessment.info:eu-repo/semantics/publishedVersio

    The program for biodiversity research in Brazil: The role of regional networks for biodiversity knowledge, dissemination, and conservation

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    The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes

    Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

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    Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

    Chloroquine Mediated Modulation of Anopheles gambiae Gene Expression

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    Plasmodium development in the mosquito is crucial for malaria transmission and depends on the parasite's interaction with a variety of cell types and specific mosquito factors that have both positive and negative effects on infection. Whereas the defensive response of the mosquito contributes to a decrease in parasite numbers during these stages, some components of the blood meal are known to favor infection, potentiating the risk of increased transmission. The presence of the antimalarial drug chloroquine in the mosquito's blood meal has been associated with an increase in Plasmodium infectivity for the mosquito, which is possibly caused by chloroquine interfering with the capacity of the mosquito to defend against the infection.In this study, we report a detailed survey of the Anopheles gambiae genes that are differentially regulated by the presence of chloroquine in the blood meal, using an A. gambiae cDNA microarray. The effect of chloroquine on transcript abundance was evaluated separately for non-infected and Plasmodium berghei-infected mosquitoes. Chloroquine was found to affect the abundance of transcripts that encode proteins involved in a variety of processes, including immunity, apoptosis, cytoskeleton and the response to oxidative stress. This pattern of differential gene expression may explain the weakened mosquito defense response which accounts for the increased infectivity observed in chloroquine-treated mosquitoes.The results of the present study suggest that chloroquine can interfere with several putative mosquito mechanisms of defense against Plasmodium at the level of gene expression and highlight the need for a better understanding of the impacts of antimalarial agents on parasite transmission
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