317 research outputs found

    Lack of lethal and sublethal effects of Cry1Ac Bt-toxin on larvae of the stingless bee Trigona spinipes

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    Abstract -Stingless bees, particularly Trigona spinipes, are important pollinators in tropical ecosystems and are potentially affected by environmental contaminants. In this study, we tested the possible negative effects on T. spinipes larvae of the ingestion of a diet contaminated with Cry1Ac Bt-toxin. This toxin is expressed in genetically modified cotton plants. A method of rearing stingless bee larvae is described in this paper. The larvae were provided with either pure larval diet, diluted larval diet, or larval diet diluted in a Cry1Ac solution compatible with the lethal pest-exposure level (50 μg/mL). Cry1Ac ingestion did not impair the development of worker larvae, but the diluted diet slightly increased larval mortality. These results indicate that harmful effects on stingless bee larvae due to the ingestion of pollen-expressed Cry1Ac toxin are unlikely under field conditions. Bacillus thuringiensis toxin / transgenic plants / environmental impact / native pollinator / risk assessmen

    Bioinformatics analysis of circulating miRNAs related to cancer following spinal cord injury

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    Patients with spinal cord injury (SCI) have an increased risk of developing esophageal, bladder and hematologic malignancies compared with the normal population. In the present study, we aimed to identify, through in silico analysis, miRNAs and their target genes related to the three most frequent types of cancer in individuals with SCI. In a previous study, we reported a pattern of expression of miRNAs in 17 sedentary SCI males compared with 22 healthy able-bodied males by TaqMan OpenArray. This list of miRNAs deregulated in SCI patients was uploaded to miRWALK2.0 to predict the target genes and pathways of selected miRNAs. We used Cytoscape software to construct the network displaying the miRNAs and their gene targets. Among the down-regulated miRNAs in SCI, 21, 19 and 20 miRNAs were potentially associated with hematological, bladder and esophageal cancer, respectively, and three target genes (TP53, CCND1 and KRAS) were common to all three types of cancer. The three up-regulated miRNAs were potentially targeted by 18, 15 and 10 genes associated with all three types of cancer. Our current bioinformatics analysis suggests the potential influence of several miRNAs on the development of cancer in SCI. In general, these data may provide novel information regarding potential molecular mechanisms involved in the development of cancer among individuals with SCI. Further studies aiming at understanding how miRNAs contribute to the development of the major cancers that affect patients after SCI may help elucidate the role of these molecules in the pathophysiology of the disease.39CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São PauloSem informação2017/23563-

    New insights into the evolution of the Trypanosoma cruzi clade provided by a new trypanosome species tightly linked to Neotropical Pteronotus bats and related to an Australian lineage of trypanosomes

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    Abstract\ud \ud Background\ud Bat trypanosomes are implicated in the evolution of the T. cruzi clade, which harbours most African, European and American trypanosomes from bats and other trypanosomes from African, Australian and American terrestrial mammals, including T. cruzi and T. rangeli, the agents of the American human trypanosomiasis. The diversity of bat trypanosomes globally is still poorly understood, and the common ancestor, geographical origin, and evolution of species within the T. cruzi clade remain largely unresolved.\ud \ud \ud Methods\ud Trypanosome sequences were obtained from cultured parasites and from museum archived liver/blood samples of bats captured from Guatemala (Central America) to the Brazilian Atlantic Coast. Phylogenies were inferred using Small Subunit (SSU) rRNA, glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH), and Spliced Leader (SL) RNA genes.\ud \ud \ud Results\ud Here, we described Trypanosoma wauwau n. sp. from Pteronotus bats (Mormoopidae) placed in the T. cruzi clade, then supporting the bat-seeding hypothesis whereby the common ancestor of this clade likely was a bat trypanosome. T. wauwau was sister to the clade T. spp-Neobats from phyllostomid bats forming an assemblage of trypanosome species exclusively of Noctilionoidea Neotropical bats, which was sister to an Australian clade of trypanosomes from indigenous marsupials and rodents, which possibly evolved from a bat trypanosome. T. wauwau was found in 26.5 % of the Pteronotus bats examined, and phylogeographical analysis evidenced the wide geographical range of this species. To date, this species was not detected in other bats, including those that were sympatric or shared shelters with Pteronotus. T. wauwau did not develop within mammalian cells, and was not infective to Balb/c mice or to triatomine vectors of T. cruzi and T. rangeli.\ud \ud \ud Conclusions\ud \ud Trypanosoma wauwau n. sp. was linked to Pteronotus bats. The positioning of the clade T. wauwau/T.spp-Neobats as the most basal Neotropical bat trypanosomes and closely related to an Australian lineage of trypanosomes provides additional evidence that the T. cruzi clade trypanosomes likely evolved from bats, and were dispersed in bats within and between continents from ancient to unexpectedly recent times.This work was supported by grants from the Brazilian agencies CNPq (PROSUL,\ud PRAFRICA and PROTAX), CAPES (PNIPB and PNPD) and FAPESP. The analysis of\ud bats from Central America, Suriname and Guyana was supported by grant\ud ‘Investissements d’Avenir’ from the Agence Nationale de la Recherche, Canada\ud (ANR-10-LABX-25-01). Archived samples from Brazilian Pteronotus were donated\ud to ACP by VC Tavares, A Césari, PA Rocha, FM Martins, MOG Lopes, CS Bernabé,\ud TG Oliveira, E Gonçalves and M Marcos. We are grateful to many student from\ud USP and researches of other universities for the inestimable help in the\ud fieldworks. We also thanks JA Rosa for the generous contribution with\ud triatomines from the insectary of UNESP-Araraquara, and CE Jared and MM\ud Antoniazzi for the access to electron microscopic facilities of the Institute\ud Butantan, Brazil. Luciana Lima is postdoctoral fellow sponsored by FAPESP, and\ud Oneida Espinosa-Álvarez is recipient of a PhD fellowship from CNPq (PROTAX)

    Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

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    Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis
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