Costa H.C.,Federal University of Minas Gerais |
Resende F.C.,Fundacao Ezequiel Dias |
Teixeira M.,University of Sao Paulo |
Dal Vechio F.,University of Sao Paulo |
Clemente C.A.,Federal University of Minas Gerais
Anais da Academia Brasileira de Ciencias | Year: 2015
A new species of Amphisbaena is described from a semi-deciduous forest in Conceicào do Mato Dentro, southern Espinhaco Range, Minas Gerais, Brazil. The following combined characters can diagnose the new species from all congeners: head round-shaped; two or three precloacal pores sequentially arranged; 190-199 body annuli; 2-3 lateral annuli; 23-25 caudal annuli; autotomy sites on caudal annuli 7-9; 12-14 dorsal segments on midbody annulus; 14-16 ventral segments on midbody annulus; three supralabials; three infralabials; postmalar row present or absent; dorsum light brown, with cream intersegmental sutures; venter cream. To date, the new species is known only from the Espinhaco Range, highlighting the importance of conservation actions for these mountains. © 2015, Academia Brasileira de Ciencias. All rights reserved.
De Souza R.A.,Fundacao Ezequiel Dias |
Diaz N.,University of Oviedo |
Nagem R.A.P.,Federal University of Minas Gerais |
Ferreira R.S.,Federal University of Minas Gerais |
Suarez D.,University of Oviedo
Journal of Computer-Aided Molecular Design | Year: 2016
Snake venom metalloproteinases are important toxins that play fundamental roles during envenomation. They share a structurally similar catalytic domain, but with diverse hemorrhagic capabilities. To understand the structural basis for this difference, we build and compare two dynamical models, one for the hemorrhagic atroxlysin-I from Bothrops atrox and the other for the non-hemorraghic leucurolysin-a from Bothrops leucurus. The analysis of the extended molecular dynamics simulations shows some changes in the local structure, flexibility and surface determinants that can contribute to explain the different hemorrhagic activity of the two enzymes. In agreement with previous results, the long Ω-loop (from residue 149 to 177) has a larger mobility in the hemorrhagic protein. In addition, we find some potentially-relevant differences at the base of the S1′ pocket, what may be interesting for the structure-based design of new anti-venom agents. However, the sharpest differences in the computational models of atroxlysin-I and leucurolysin-a are observed in the surface electrostatic potential around the active site region, suggesting thus that the hemorrhagic versus non-hemorrhagic activity is probably determined by protein surface determinants. © 2015 Springer International Publishing Switzerland.
Caldas S.,Federal University of Ouro Preto |
Caldas I.S.,Federal University of Ouro Preto |
Diniz L.D.F.,Federal University of Ouro Preto |
Lima W.G.D.,Federal University of Ouro Preto |
And 5 more authors.
Acta Tropica | Year: 2012
The lack of an accurate diagnosis has been a serious obstacle to the advancement of the anti-. Trypanosoma cruzi chemotherapy and long-term infection can result in different health risks to human. PCRs are alternative methods, more sensitive than conventional parasitological techniques, which due to their low sensitivities are considered unsuitable for these purposes. The aim of this study was to investigate a sensitive diagnostic strategy to quantify blood and cardiac tissues parasites based on real-time PCR tools during acute and chronic phases of murine Chagas disease, as well as to monitor the evolution of infection in those mice under specific treatment. In parallel, fresh blood examination, immunological analysis and quantification of cardiac inflammation were also performed to confront and improve real-time PCR data. Similar profiles of parasitemia curves were observed in both quantification techniques during the acute phase of the infection. In contrast, parasites could be quantified only by real-time PCR at 60 and 120 days of infection. In cardiac tissue, real-time PCR detected . T. cruzi DNA in 100% of infected mice, and using this tool a significant Pearson correlation between parasite load in peripheral blood and in cardiac tissue during acute and chronic phases was observed. Levels of serum CCL2, CCL5 and nitric oxide were coincident with parasite load but focal and diffuse mononuclear infiltrates was observed, even with significant (. p<. 0.05) reduction of parasitism after 60 days of infection. Later, this methodology was used to monitor the evolution of infection in animals treated with itraconazole (Itz). Itz-treatment induced a reduction of parasite load in both blood and cardiac muscle at the treatment period, but after the end of chemotherapy an increase of parasitism was detected. Interestingly, inflammatory mediators levels and heart inflammation intensity had similar evolution to the parasite load, in the group of animals treated. Taken together, our data show that real-time PCR strategy used was suitable for studies of murine . T. cruzi infection and may prove useful in investigations involving experimental chemotherapy of the disease and the benefits of treatment in relation to parasitism and inflammatory response. © 2012 Elsevier B.V..
Gewehr C.,Institute Ensino E Pesquisa Da Santa Casa Of Belo Horizonte |
Oliveira S.M.,Federal University of Santa Maria |
Rossato M.F.,Federal University of Santa Maria |
Trevisan G.,Federal University of Santa Maria |
And 6 more authors.
PLoS Neglected Tropical Diseases | Year: 2013
Background: The frequency of accidental spider bites in Brazil is growing, and poisoning due to bites from the spider genus Phoneutria nigriventer is the second most frequent source of such accidents. Intense local pain is the major symptom reported after bites of P. nigriventer, although the mechanisms involved are still poorly understood. Therefore, the aim of this study was to identify the mechanisms involved in nociception triggered by the venom of Phoneutria nigriventer (PNV).Methodology/Principal Findings: Twenty microliters of PNV or PBS was injected into the mouse paw (intraplantar, i.pl.). The time spent licking the injected paw was considered indicative of the level of nociception. I.pl. injection of PNV produced spontaneous nociception, which was reduced by arachnid antivenin (ArAv), local anaesthetics, opioids, acetaminophen and dipyrone, but not indomethacin. Boiling or dialysing the venom reduced the nociception induced by the venom. PNV-induced nociception is not dependent on glutamate or histamine receptors or on mast cell degranulation, but it is mediated by the stimulation of sensory fibres that contain serotonin 4 (5-HT4) and vanilloid receptors (TRPV1). We detected a kallikrein-like kinin-generating enzyme activity in tissue treated with PNV, which also contributes to nociception. Inhibition of enzymatic activity or administration of a receptor antagonist for kinin B2 was able to inhibit the nociception induced by PNV. PNV nociception was also reduced by the blockade of tetrodotoxin-sensitive Na+ channels, acid-sensitive ion channels (ASIC) and TRPV1 receptors.Conclusion/Significance:Results suggest that both low- and high-molecular-weight toxins of PNV produce spontaneous nociception through direct or indirect action of kinin B2, TRPV1, 5-HT4 or ASIC receptors and voltage-dependent sodium channels present in sensory neurons but not in mast cells. Understanding the mechanisms involved in nociception caused by PNV are of interest not only for better treating poisoning by P. nigriventer but also appreciating the diversity of targets triggered by PNV toxins. © 2013 Gewehr et al.
Costa H.C.,Federal University of Minas Gerais |
Cotta G.A.,Fundacao Ezequiel Dias |
MacCulloch R.D.,Royal Ontario Museum
Check List | Year: 2015
The snake species Pseudoboa coronata has wide distribution from central Brazil to coastal Venezuela and the Guianas, eastern Bolivia, Colombia, Ecuador, and Peru. In this note, the known distribution range of P. coronata is extended eastward to the border between the states of Bahia and Pernambuco, and southward to Cachoeira Alta, state of Goiás, both in Brazil. Considering the limited biogeographic information for most taxa, reports like this add significant data for future studies on biogeography, taxonomy, and conservation biology. © 2015 Check List and Authors.