379 research outputs found

    Comparação de tamanhos de quadrats na amostragem do bivalve não-nativo Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae)

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    We aimed to designate which is the best quadrat area to be used in sampling of C. fluminea for determination of their population parameters. The quadrat of 0.0625 m2 showed the best cost efficiency and a lowest sampling effort, being recommended for study of C. fluminea in lentic environments.Nós indicamos qual é a melhor área de quadrat a ser utilizada na amostragem de C. fluminea para determinação de seus parâmetros populacionais. O quadrat de 0,0625 m2 apresentou o melhor custo-benefício e um menor esforço amostral, sendo recomendado para estudo de C. fluminea em ambientes lênticos.Facultad de Ciencias Naturales y Muse

    Description of evandromyia spelunca, a new phlebotomine species of the cortelezzii complex, from a cave in Minas Gerais State, Brazil (Diptera: Psychodidae: Phlebotominae)

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    <p>Abstract</p> <p>Background</p> <p>The cave fauna of the Brazil is poorly documented, and among the insects those live or frequent caves and their adjacent environments phlebotomine sand flies call for special attention because several species are vectors of pathogens among vertebrates hosts. A new species of sand fly from Minas Gerais is described based in females and males collected in a cave of the municipality of Lassance.</p> <p>Results</p> <p>The morphological characters of the new species permit to include in the Evandromyia genus, cortelezzii complex. This complex consists of three species: Evandromyia corumbaensis (Galati, Nunes, Oshiro & Rego, 1989), Evandromyia cortelezzii (Brethes, 1923) and Evandromyia sallesi (Galvao & Coutinho, 1940).</p> <p>Conclusions</p> <p>The new species can be separate from the others of the cortelezzii complex through morphological characters of the male terminalia and female spermathecae.</p

    Critical assessment of enhancement factor measurements in surface-enhanced raman scattering on different substrates

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    The SERS enhancement factor (SERS-EF) is one of the most important parameters that characterizes the ability of a given substrate to enhance the Raman signal for SERS applications. The comparison of SERS intensities and SERS-EF values across different substrates is a common practice to unravel the performance of a given substrate. In this study, it is shown that such a comparison may lack significance if we compare substrates of very distinct nature and optical properties. It is specifically shown that the SERS-EF values for static substrates (e.g. immobilized metallic nanostructures) cannot be compared to those of dynamic ones (e.g. colloidal metal nanoparticle solutions), and that the optical properties for the latter show strong dependence on the metal-molecule interaction dynamics. The most representative experimental results concerning the dynamic substrates have been supported by generalized Mie theory simulations, which are tools used to describe the substrate complexity and the microscopic information not usually taken into account17332129421301CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPES

    Integrative multi-kinase approach for the identification of potent antiplasmodial hits

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    Malaria is a tropical infectious disease that affects over 219 million people worldwide. Due to the constant emergence of parasitic resistance to the current antimalarial drugs, the discovery of new antimalarial drugs is a global health priority. Multi-target drug discovery is a promising and innovative strategy for drug discovery and it is currently regarded as one of the best strategies to face drug resistance. Aiming to identify new multi-target antimalarial drug candidates, we developed an integrative computational approach to select multi-kinase inhibitors for Plasmodium falciparum calcium-dependent protein kinases 1 and 4 (CDPK1 and CDPK4) and protein kinase 6 (PK6). For this purpose, we developed and validated shape-based and machine learning models to prioritize compounds for experimental evaluation. Then, we applied the best models for virtual screening of a large commercial database of drug-like molecules. Ten computational hits were experimentally evaluated against asexual blood stages of both sensitive and multi-drug resistant P. falciparum strains. Among them, LabMol-171, LabMol-172, and LabMol-181 showed potent antiplasmodial activity at nanomolar concentrations (EC50 15 folds. In addition, LabMol-171 and LabMol-181 showed good in vitro inhibition of P. berghei ookinete formation and therefore represent promising transmission-blocking scaffolds. Finally, docking studies with protein kinases CDPK1, CDPK4, and PK6 showed structural insights for further hit-to-lead optimization studies.7CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP405996/2016-0; 400760/2014-2Sem informação2018/05926-2; 2017/02353-9; 2012/16525-2; 2017/18611-7; 2018/07007-4; 2013/13119-6; 2018/24878-9; 2015/20774-

    Proteomic analysis of Chromobacterium violaceum and its adaptability to stress

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    Chromobacterium violaceum (C. violaceum) occurs abundantly in a variety of ecosystems, including ecosystems that place the bacterium under stress. This study assessed the adaptability of C. violaceum by submitting it to nutritional and pH stresses and then analyzing protein expression using bi-dimensional electrophoresis (2-DE) and Maldi mass spectrometry. Chromobacterium violaceum grew best in pH neutral, nutrient-rich medium (reference conditions); however, the total protein mass recovered from stressed bacteria cultures was always higher than the total protein mass recovered from our reference culture. The diversity of proteins expressed (repressed by the number of identifiable 2-DE spots) was seen to be highest in the reference cultures, suggesting that stress reduces the overall range of proteins expressed by C. violaceum. Database comparisons allowed 43 of the 55 spots subjected to Maldi mass spectrometry to be characterized as containing a single identifiable protein. Stress-related expression changes were noted for C. violaceum proteins related to the previously characterized bacterial proteins: DnaK, GroEL-2, Rhs, EF-Tu, EF-P; MCP, homogentisate 1,2-dioxygenase, Arginine deiminase and the ATP synthase β-subunit protein as well as for the ribosomal protein subunits L1, L3, L5 and L6. The ability of C. violaceum to adapt its cellular mechanics to sub-optimal growth and protein production conditions was well illustrated by its regulation of ribosomal protein subunits. With the exception of the ribosomal subunit L3, which plays a role in protein folding and maybe therefore be more useful in stressful conditions, all the other ribosomal subunit proteins were seen to have reduced expression in stressed cultures. Curiously, C. violeaceum cultures were also observed to lose their violet color under stress, which suggests that the violacein pigment biosynthetic pathway is affected by stress. Analysis of the proteomic signatures of stressed C. violaceum indicates that nutrient-starvation and pH stress can cause changes in the expression of the C. violaceum receptors, transporters, and proteins involved with biosynthetic pathways, molecule recycling, energy production. Our findings complement the recent publication of the C. violeaceum genome sequence and could help with the future commercial exploitation of C. violeaceum
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