Search results for "96"
showing 10 items of 2333 documents
Nuclear rDNA-based molecular clock of the evolution of Triatominae (Hemiptera : Reduviidae), vectors of Chagas disease
2000
The evolutionary history and times of divergence of triatomine bug lineages are estimated from molecular clocks inferred from nucleotide sequences of the small subunit SSU (18S) and the second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA of these reduviids. The 18S rDNA molecular clock rate in Triatominae, and Prosorrhynchan Hemiptera in general, appears to be of 1.8% per 100 million years (my). The ITS-2 molecular clock rate in Triatominae is estimated to be around 0.4-1% per 1 my, indicating that ITS-2 evolves 23-55 times faster than 18S rDNA. Inferred chronological data about the evolution of Triatominae fit well with current hypotheses on their evolutionary histories…
Genetic structure of Triatoma venosa (Hemiptera: Reduviidae): molecular and morphometric evidence.
2006
Triatoma venosa presents a restricted geographical distribution in America and is considered as a secondary vector of Chagas disease in Colombia and Ecuador. A total of 120 adult insects were collected in domestic and peridomestic habitats in an endemic area of the department of Boyaca, Colombia, in order to determine their genetic structure through morphometric and molecular techniques. The head and wings of each specimen were used for the analyses of size, shape, and sexual dimorphism. A significant sexual dimorphism was found, although no differences in size among the studied groups were detected. Differences were found in the analyzed structures except for male heads. DNA was extracted …
A nuclear ribosomal DNA pseudogene in triatomines opens a new research field of fundamental and applied implications in Chagas disease
2015
A pseudogene, designated as "ps(5.8S+ITS-2)", paralogous to the 5.8S gene and internal transcribed spacer (ITS)-2 of the nuclear ribosomal DNA (rDNA), has been recently found in many triatomine species distributed throughout North America, Central America and northern South America. Among characteristics used as criteria for pseudogene verification, secondary structures and free energy are highlighted, showing a lower fit between minimum free energy, partition function and centroid structures, although in given cases the fit only appeared to be slightly lower. The unique characteristics of "ps(5.8S+ITS-2)" as a processed or retrotransposed pseudogenic unit of the ghost type are reviewed, wi…
DNA multigene sequencing of topotypic specimens of the fascioliasis vector Lymnaea diaphana and phylogenetic analysis of the genus Pectinidens (Gastr…
2012
Freshwater lymnaeid snails are crucial in defining transmission and epidemiology of fascioliasis. In South America, human endemic areas are related to high altitudes in Andean regions. The species Lymnaea diaphana has, however, been involved in low altitude areas of Chile, Argentina and Peru where human infection also occurs. Complete nuclear ribosomal DNA 18S, internal transcribed spacer (ITS)-2 and ITS-1 and fragments of mitochondrial DNA 16S and cytochrome c oxidase (cox)1 genes of L. diaphana specimens from its type locality offered 1,848, 495, 520, 424 and 672 bp long sequences. Comparisons with New and Old World Galba/Fossaria, Palaearctic stagnicolines, Nearctic stagnicolines, Old Wo…
TRYPANOSOMES OF SOME FENNOSCANDIAN BIRDS
1994
Linear measurements and derived indices of trypanosomes from species of Fennoscandian birds were compared to those reported form Trypanosoma avium, T. everetti, T. ontarioensis and T. paddae. The trypanosomes encountered in the Fennoscandian birds were identified as T. avium from Tengmalm's owl Aegolius funereus and the pied flycatcher Ficedula hypoleuca, T. everetti from the great tit Parus major and collared flycatcher F. albicollis and T. ontarioensis from the collared flycatcher; T. paddae was not seen.
Value of morphotyping for the characterization of Candida albicans clinical isolates
2005
Until recently, morphotyping, a method evaluating fringe and surface characteristics of streak colonies grown on malt agar, has been recommended as a simple and unexpensive typing method for Candida albicans isolates. The discriminatory power and reproducibility of Hunter's modified scheme of Phongpaichit's morphotyping has been evaluated on 28 C. albicans isolates recovered from the oral cavity of asymptomatic human immunodeficiency virus-positive subjects, and compared to two molecular typing methods: randomly amplified polymorphic DNA (RAPD) fingerprinting, and contour clamped homogeneous electric field (CHEF) electrophoretic karyotyping. Morphological features of streak colonies allowed…
Evolution of coauthorship networks: worldwide scientific production on leishmaniasis.
2013
Introduction Collaboration is one of the defining features of contemporary scientific research, and it is particularly important with regard to neglected diseases that primarily affect developing countries. Methods The present study has identified publications on leishmaniasis in the Medline database from 1945 to 2010, analyzing them according to bibliometric indicators and statistics from social network analysis. Examining aspects such as scientific production, diachronic evolution, and collaboration and configuration of the research groups in the field, we have considered the different types of Leishmania studied and the institutional affiliation and nationality of the authors. Results Se…
Lymnaea cousinni (Gastropoda: Lymnaeidae) as transmitter of fascioliasis
2007
Dear Editor,In the article entitled “First report of Lymnaea cou-sini Jousseaume, 1887 naturally infected with Fasciolahepatica (Linnaeus, 1758) (Trematoda: Digenea) inMachachi, Ecuador” recently published by AngelVillavicencio A and Mauricio Carvalho de Vasconcellosin Memorias do Instituto Oswaldo Cruz (vol. 100, is-sue 7, pages 735-737, November 2005), it is stated thattheir finding in Ecuador represents the first report ofspecimens of this lymnaeid species naturally infectedby the liver fluke. However, it is well known from longago that this species acts as intermediate host of fascio-liasis in Andean countries. In the first half of the lastcentury, Brumpt et al. (1939-1940) already demo…
Urban MEMS based seismic network for post-earthquakes rapid disaster assessment
2014
Abstract. In this paper, we introduce a project for the realization of the first European real-time urban seismic network based on Micro Electro-Mechanical Systems (MEMS) technology. MEMS accelerometers are a highly enabling technology, and nowadays, the sensitivity and the dynamic range of these sensors are such as to allow the recording of earthquakes of moderate magnitude even at a distance of several tens of kilometers. Moreover, thanks to their low cost and smaller size, MEMS accelerometers can be easily installed in urban areas in order to achieve an urban seismic network constituted by high density of observation points. The network is being implemented in the Acireale Municipality (…
Investigating the Effects of Differential Learning on Golfers’ Pitching Performance as a Function of Handicap
2022
Traditionally, golf instruction has been oriented toward imitation of role models, guided by errors that surround a channel of supposedly correct repetition. Recent motor learning approaches relying on the dynamics of living systems suggest the inclusion of additional noise during practice for supporting players’ movement exploration and improving adaptability that in consequence will lead to increased performance. While the effectiveness of this approach has now been demonstrated in many sports, research exploring the effects of differential learning (DL) in golf is scarce, especially when considering different shot distances and players with various handicap levels. Therefore, the p…