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991.
Maria C Anholeti Rodrigo C Duprat Maria R Figueiredo Maria AC Kaplan Marcelo Guerra Santos Marcelo S Gonzalez Norman A Ratcliffe Denise Feder Selma R Paiva Cicero B Mello 《Memórias do Instituto Oswaldo Cruz》2015,110(5):629-635
Studies evaluated the effects of hexanic extracts from the fruits and flowers
ofClusia fluminensis and the main component of the flower
extract, a purified benzophenone (clusianone), against Aedes
aegypti. The treatment of larvae with the crude fruit or flower extracts
from C. fluminensis did not affect the survival ofAe.
aegypti (50 mg/L), however, the flower extracts significantly delayed
development of Ae. aegypti. In contrast, the clusianone (50 mg/L) isolate from the
flower extract, representing 54.85% of this sample composition, showed a highly
significant inhibition of survival, killing 93.3% of the larvae and completely
blocking development of Ae. aegypti. The results showed, for the first time, high
activity of clusianone against Ae. aegypti that both killed and inhibited mosquito
development. Therefore, clusianone has potential for development as a biopesticide
for controlling insect vectors of tropical diseases. Future work will elucidate the
mode of action of clusianone isolated from C. fluminensis. 相似文献
992.
Louisy Sanches dos Santos Camila Azevedo Antunes Cintia Silva dos Santos José Augusto Adler Pereira Priscila Soares Sabbadini Maria das Gra?as de Luna Vasco Azevedo Raphael Hirata Júnior Andreas Burkovski Lídia Maria Buarque de Oliveira Asad Ana Luíza Mattos-Guaraldi 《Memórias do Instituto Oswaldo Cruz》2015,110(5):662-668
Corynebacterium diphtheriae, the aetiologic agent of diphtheria,
also represents a global medical challenge because of the existence of invasive
strains as causative agents of systemic infections. Although tellurite
(TeO32-) is toxic to most microorganisms, TeO32--resistant
bacteria, including C. diphtheriae, exist in
nature. The presence of TeO32--resistance (TeR)
determinants in pathogenic bacteria might provide selective advantages in the natural
environment. In the present study, we investigated the role of the putative
TeR determinant (CDCE8392_813gene) in the virulence
attributes of diphtheria bacilli. The disruption of CDCE8392_0813 gene expression in
the LDCIC-L1 mutant increased susceptibility to TeO32- and reactive oxygen
species (hydrogen peroxide), but not to other antimicrobial agents. The LDCIC-L1
mutant also showed a decrease in both the lethality of Caenorhabditis elegans
and the survival inside of human epithelial cells compared to wild-type
strain. Conversely, the haemagglutinating activity and adherence to and formation of
biofilms on different abiotic surfaces were not regulated through the CDCE8392_0813
gene. In conclusion, the CDCE8392_813 gene contributes to the TeR and
pathogenic potential of C. diphtheriae. 相似文献
993.
Jefferson José da Silva Santos Tereza Magalh?es José Valter Joaquim Silva Junior Andréa Nazaré Monteiro Rangel da Silva Marli Tenório Cordeiro Laura Helena Vega Gonzales Gil 《Memórias do Instituto Oswaldo Cruz》2015,110(5):677-683
Full-length dengue virus (DENV) cDNA clones are an invaluable tool for many studies,
including those on the development of attenuated or chimeric vaccines and on
host-virus interactions. Furthermore, the importance of low passage DENV infectious
clones should be highlighted, as these may harbour critical and unique
strain-specific viral components from field-circulating isolates. The successful
construction of a functional Brazilian low passage DENV serotype 2 full-length clone
through homologous recombination reported here supports the use of a strategy that
has been shown to be highly useful by our group for the development of flavivirus
infectious clones and replicons. 相似文献
994.
995.
Phylogeny and historical biogeography of the paper wasp genus Polistes (Hymenoptera: Vespidae): implications for the overwintering hypothesis of social evolution 下载免费PDF全文
Bernardo F. Santos Ansel Payne James M. Carpenter 《Cladistics : the international journal of the Willi Hennig Society》2015,31(5):535-549
The phylogeny of the paper wasp genus Polistes is investigated using morphological and behavioural characters, as well as molecular data from six genes (COI, 12S, 16S, 28S, H3, and EF1‐α). The results are used to investigate the following evolutionary hypotheses about the genus: (i) that Polistes first evolved in Southeast Asia, (ii) that dispersal to the New World occurred only once, and (iii) that long‐term monogyny evolved as an adaptation to overwintering in a temperate climate. Optimization of distribution records on the recovered tree does not allow unambiguous reconstruction of the ancestral area of Polistes. While the results indicate that Polistes dispersed into the New World from Asia, South America is recovered as the ancestral area for all New World Polistes: Nearctic species groups evolved multiple times from this South American stock. The final tree topology suggests strongly that the genus first arose in a tropical environment, refuting the idea of monogyny as an overwintering adaptation. 相似文献
996.
Daniel J.V.A. dos Santos 《Molecular simulation》2015,41(5-6):455-462
The effect of replacing bis(trifluoromethylsulphonyl)imide ([NTf2]) by hexafluorophosphate ([PF6]) in room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulphonyl)imide ([BMIm][NTf2]) confined between two gold interfaces is herein reported through molecular dynamics simulations using all-atom non-polarisable force-fields. Five systems were studied ranging from pure [BMIm][NTf2] to pure [BMIm][PF6], with [PF6] molar fractions of 0, 0.125, 0.25, 0.375 and 0.5. Special attention was drawn to investigate the impact of the [PF6] anion on the IL, in particular on the first layers of the liquid in close contact with the solid gold surface. 相似文献
997.
998.
999.
High osmolarity glycerol response PtcB phosphatase is important for Aspergillus fumigatus virulence 下载免费PDF全文
Lizziane K. Winkelströter Vinícius Leite Pedro Bom Patrícia Alves de Castro Leandra Naira Zambelli Ramalho Maria Helena S. Goldman Neil Andrew Brown Ranjith Rajendran Gordon Ramage Elodie Bovier Thaila Fernanda dos Reis Marcela Savoldi Daisuke Hagiwara Gustavo H. Goldman 《Molecular microbiology》2015,96(1):42-54
Aspergillus fumigatus is a fungal pathogen that is capable of adapting to different host niches and to avoid host defenses. An enhanced understanding of how, and which, A. fumigatus signal transduction pathways are engaged in the regulation of these processes is essential for the development of improved disease control strategies. Protein phosphatases are central to numerous signal transduction pathways. To comprehend the functions of protein phosphatases in A. fumigatus, 32 phosphatase catalytic subunit encoding genes were identified. We have recognized PtcB as one of the phosphatases involved in the high osmolarity glycerol response (HOG) pathway. The ΔptcB mutant has both increased phosphorylation of the p38 MAPK (SakA) and expression of osmo‐dependent genes. The ΔptcB strain was more sensitive to cell wall damaging agents, had increased chitin and β‐1,3‐glucan, and impaired biofilm formation. The ΔptcB strain was avirulent in a murine model of invasive pulmonary aspergillosis. These results stress the importance of the HOG pathway in the regulation of pathogenicity determinants and virulence in A. fumigatus. 相似文献
1000.
Eliana F. Oliveira Marcelo Gehara Vinícius A. São‐Pedro Xin Chen Edward A. Myers Frank T. Burbrink Daniel O. Mesquita Adrian A. Garda Guarino R. Colli Miguel T. Rodrigues Federico J. Arias Hussam Zaher Rodrigo M. L. Santos Gabriel C. Costa 《Molecular ecology》2015,24(23):5957-5975
Two main hypotheses have been proposed to explain the diversification of the Caatinga biota. The riverine barrier hypothesis (RBH) claims that the São Francisco River (SFR) is a major biogeographic barrier to gene flow. The Pleistocene climatic fluctuation hypothesis (PCH) states that gene flow, geographic genetic structure and demographic signatures on endemic Caatinga taxa were influenced by Quaternary climate fluctuation cycles. Herein, we analyse genetic diversity and structure, phylogeographic history, and diversification of a widespread Caatinga lizard (Cnemidophorus ocellifer) based on large geographical sampling for multiple loci to test the predictions derived from the RBH and PCH. We inferred two well‐delimited lineages (Northeast and Southwest) that have diverged along the Cerrado–Caatinga border during the Mid‐Late Miocene (6–14 Ma) despite the presence of gene flow. We reject both major hypotheses proposed to explain diversification in the Caatinga. Surprisingly, our results revealed a striking complex diversification pattern where the Northeast lineage originated as a founder effect from a few individuals located along the edge of the Southwest lineage that eventually expanded throughout the Caatinga. The Southwest lineage is more diverse, older and associated with the Cerrado–Caatinga boundaries. Finally, we suggest that C. ocellifer from the Caatinga is composed of two distinct species. Our data support speciation in the presence of gene flow and highlight the role of environmental gradients in the diversification process. 相似文献