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Search Results: 1 - 10 of 523233 matches for " Paulo E. M. Ribolla "
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Knockdown resistance in pyrethroid-resistant horn fly (Diptera: Muscidae) populations in Brazil
Sabatini, Gustavo A.;Ribolla, Paulo E. M.;Barros, Antonio T. M.;Guerrero, Felix D.;Schumaker, Terezinha T. S.;
Revista Brasileira de Parasitologia Veterinária , 2009, DOI: 10.4322/rbpv.01803002
Abstract: to investigate the kdr (knockdown resistance) resistance-associated gene mutation and determine its frequency in pyrethroid-resistant horn fly (haematobia irritans) populations, a total of 1,804 horn flies of 37 different populations from all brazilian regions (north, northeast, central-west, southeast, and south) were molecular screened through polymerase chain reaction (pcr). the kdr gene was not detected in 87.08% of the flies. however, the gene was amplified in 12.92% of the flies, of which 11.70% were resistant heterozygous and 1.22% were resistant homozygous. deviation from hardy-weinberg equilibrium (hwe) was found only in 1 ranch with an excess of heterozygous. when populations were grouped by region, three metapopulations showed significant deviations of hwe (central-west population, south population and southeast population). this indicates that populations are isolated one from another and kdr occurrence seems to be an independent effect probably reflecting the insecticide strategy used by each ranch. although resistance to pyrethroids is disseminated throughout brazil, only 48% of resistant populations had kdr flies, and the frequency of kdr individuals in each of these resistant populations was quite low. but this study shows that, with the apparent exception of the northeast region, the kdr mechanism associated with pyrethroid resistance occurs all over brazil.
Genetic variability in geographical populations of Aedes aegypti (Diptera, Culicidae) in Brazil elucidated by molecular markers
Paduan, Karina dos Santos;Araújo-Júnior, Jo?o P.;Ribolla, Paulo E.M.;
Genetics and Molecular Biology , 2006, DOI: 10.1590/S1415-47572006000200030
Abstract: the tropical mosquito, aedes aegypti is the most important domestic vector of urban yellow fever and dengue. genetic population studies on this vector are important because they may lead to new tools for surveillance. an analysis of genetic structure was conducted among populations of a. aegypti from 11 localities in four demographic regions within six brazilian federal states. markers included 21 random amplified polymorphic dna (rapd) loci. rapd markers were detected among populations and cluster analysis revealed two main groups. we found high genetic polymorphism (hs = 0.224) and high levels of genetic differentiation between populations from different states (gst = 0.430), as well as in populations from cities in the same state (gst = 0.410). these results indicate significant differentiation in a. aegypti populations in brazil. regression analyses of geographic distances and pairwise fst values estimated from rapd markers showed that there is a correlation between genetic structure and geographic localization.
Genetic Structure of Lutzomyia longipalpis Populations in Mato Grosso Do Sul, Brazil, Based on Microsatellite Markers
Mirella F. C. Santos, Paulo E. M. Ribolla, Diego P. Alonso, José D. Andrade-Filho, Aline E. Casaril, Alda M. T. Ferreira, Carlos E. S. Fernandes, Reginaldo P. Brazil, Alessandra G. Oliveira
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074268
Abstract: Background Lutzomyia longipalpis (Diptera: Psychodidae) is the major vector of Leishmania (Leishmania) infantum and thus plays a crucial role in the epidemiology of American visceral leishmaniasis (AVL). This vector is the best studied species of sand fly in the Neotropical region. Many studies claim that this vector is in fact a species complex; however there is still no consensus regarding the number of species that belong into this complex or the geographical distribution of sibling species. The aim of the present study was to analyze the genetic relationships within?Lu. longipalpis?populations in the state of Mato Grosso do Sul (MS), Brazil. Methodology/Principal Findings We collected 30 Lu. longipalpis (15 females and 15 males) from five localities (Campo Grande, Três Lagoas, Aquidauana, Miranda and Bonito) and 30 Lu. Cruzi from Corumbá, totaling 180 sandflies from MS, and 30 Lu. longipalpis from Estrela de Alagoas, state of Alagoas (AL), Northeast Brazil. We show that eight previously described microsatellite loci were sufficient in distinguishing Lu. longipalpis from Lu. Cruzi, which is a closely related species, and in differentiating between Lu. longipalpis collected in MS versus Estrela de Alagoas. Analyses of the genotypes revealed introgression between sympatric Lu. longipalpis and Lu. Cruzi. Conclusions/Significance Our findings support the hypothesis of cryptic species within the Lu. longipalpis complex. Furthermore, our data revealed introgression between Lu. longipalpis and Lu. cruzi. This phenomenon should be further investigated to determine the level and incidence of hybridization between these two species. We also demonstrated that microsatellite markers are a powerful tool for differentiating sand fly populations and species. The present study has elucidated the population structure of Lu. longipalpis in MS and, by extension, the Neotropical Lu. longipalpis complex itself.
Population dynamics, structure and behavior of Anopheles darlingi in a rural settlement in the Amazon rainforest of Acre, Brazil
Paulo Moutinho, Luis Gil, Rafael Cruz, Paulo Ribolla
Malaria Journal , 2011, DOI: 10.1186/1475-2875-10-174
Abstract: The study area, known as Ramal do Granada, is a rural settlement inside the Amazon basin in the state of Acre. Population variations and density have been analysed by species behaviour, and molecular analysis has been measured by ND4 mitochondrial gene sequencing.The results show higher density in collections near a recent settlement, suggesting that a high level of colonization decreases the vector presence. The biting activity showed higher activity at twilight and major numbers of mosquitos in the remaining hours of the night in months of high density. From a sample of 110 individual mosquitoes, 18 different haplotypes were presented with a diversity index of 0.895, which is higher than that found in other Anopheles studies.An. darlingi depends on forested regions for their larval and adult survival. In months with higher population density, the presence of mosquitoes persisted in the second part of the night, increasing the vector capacity of the species. Despite the intra-population variation in the transition to rainy season, the seasonal distribution of haplotypes shows no change in the structure population of An. darlingi.Malaria is one of the most important tropical diseases in the world. WHO data report a total of 106 malaria-endemic countries and 151 million estimated cases in 2009 [1]. In South America, there are a high number of disease notifications in Brazil, Colombia, Peru, Venezuela, Suriname and Bolivia. These countries have large tracts of Amazon rainforest, South American biome and habitats for many Anopheles species that have high potential to be malaria vectors [2,3].Brazil has the largest number of malaria cases and malaria-related deaths in the Americas, and 15% of its population lives in at-risk areas, which are concentrated in the states of the Amazon Basin, with an average of 500 thousand notifications per year [4]. The strategies and targets for malaria control include diagnosis, disease treatment and prevention by mosquito control. There
Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam
Erika HE Hoffmann, Paulo EM Ribolla, Marcelo U Ferreira
Malaria Journal , 2003, DOI: 10.1186/1475-2875-2-24
Abstract: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed : Polyα, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60.The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country.Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages.Despite its relatively recent expansion in human populations [1], Plasmodium falciparum displays extensive genetic variation in most surface antigens, affecting the development of effective immune responses [2]. Understanding the patterns and mechanisms of DNA sequence variation in major P. falciparum surface antigens is important for predicting the efficacy of immunization strategies [3].The merozoite surface protein-1 (MSP-1) of P. falciparum is a prime malaria vaccine candidate antigen. Its coding sequence may be divided into 17 blocks, according to the levels of inter-allele divergence (Figure 1A). Most variation is dimorphic: sequences may be grouped into one of two allelic families (K1 and MAD20). Block 2 represents an exception to dimorphism, sin
Winter Latitudinal Population Age-Structure of a Migratory Seagull (Larus fuscus) Differs between Its Two Major Migratory Flyways
Paulo A. M. Marques,Paulo E. Jorge
International Journal of Ecology , 2013, DOI: 10.1155/2013/737616
Abstract: The migration is energy-demanding and is expected to greatly affect the distribution of individuals over the species range and condition the choice of migratory routes. We investigated the wintering distributions and migratory flyways use of geographically contiguous populations of Lesser Black-backed Gulls (Larus fuscus) and difference in population winter age structure between migratory flyways. Recoveries of metal ringed pulli from Denmark, Sweden, and Finland were used. The results showed that contiguous populations can have distinct wintering distribution patterns and migratory flyways. More importantly, we found that depending on the place of origin, the population winter distribution may or may not show a latitudinal cline in the age structure. The population migrating via the eastern Atlantic flyway (western flyway) showed a winter age-related latitudinal cline, with adults staying at more northern latitudes than immatures. In contrast, no such pattern was found in the population migrating along the Mediterranean/Black sea flyway (eastern flyway). Interestingly, immatures within the eastern population showed a more dispersed pattern of migratory bearings. Overall, our results enhance the importance of the migration flyway in shaping the age structure of populations in the winter quarters and how it may influence the effect of other factors like sexual maturation. 1. Introduction During migration, geographically distinct populations of the same species can face different challenges when moving between breeding and wintering areas. Ecological barriers, such as the Sahara Desert, or mountain ranges, such as the Alps or the Pyrenees, contribute to the shaping of migratory routes and the patterns of distribution of the species that have to cross them [1, 2]. Thus, in species that are spread over wide geographical ranges, populations from the extremes of the distribution can have different migratory problems to solve and can thus develop distinct migratory behaviours in response to the specific ecological constraints (e.g., different migratory routes or migration timings [3–5]). A longitudinal effect on the wintering distribution of populations has been well documented [6–9]; birds that breed furthest west in the breeding range tend to winter furthest west in the nonbreeding range, while those that breed furthest east also winter furthest east. This pattern represents a general tendency revealed by ringing recovery data for most groups of birds [1, 2]. Similarly, latitudinal effects can also be found within and among populations of the same species
Optimal Control of Finite Dimensional Quantum Systems
Paulo E. M. F. Mendonca
Physics , 2009,
Abstract: This thesis addresses the problem of developing a quantum counter-part of the well established classical theory of control. We dwell on the fundamental fact that quantum states are generally not perfectly distinguishable, and quantum measurements typically introduce noise in the system being measured. Because of these, it is generally not clear whether the central concept of the classical control theory -- that of observing the system and then applying feedback -- is always useful in the quantum setting. We center our investigations around the problem of transforming the state of a quantum system into a given target state, when the system can be prepared in different ways, and the target state depends on the choice of preparation. We call this the "quantum tracking problem" and show how it can be formulated as an optimization problem that can be approached both numerically and analytically. This problem provides a simple route to the characterization of the quantum trade-off between information gain and disturbance, and is seen to have several applications in quantum information.
Species structure of sand fly (Diptera: Psychodidae) fauna in the Brazilian western Amazon
Gil, Luiz Herman Soares;Araújo, Maisa da Silva;Villalobos, Juan Miguel;Camargo, Luis Marcelo Aranha;Ozaki, Luiz Shozo;Fontes, Cor Jesus Fernandes;Ribolla, Paulo Eduardo Martins;Katsuragawa, Tony Hiroshi;Cruz, Rafael Mesquita;Silva, Alexandre de Almeida e;Silva, Luiz Hildebrando Pereira da;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000700002
Abstract: we surveyed areas of the state of rond?nia in western amazon for phlebotomine, which are potential vectors of leishmaniasis. a total of 5,998 specimens were captured, resulting in the identification of 48 species within the lutzomyia (99.98%) and brumptomyia (0.02%) genera. the predominant species was lutzomyia davisi, followed by lutzomyia umbratilis, lutzomyia llanosmartinsi, lutzomyia c. carrerai, lutzomyia dendrophyla, lutzomyia nevesi and lutzomyia whitmani. all sand flies identified as vectors for cutaneous leishmaniasis in brazil, i.e., lu. davisi, lu. umbratilis, lu. c. carrerai and lu. whitmani, were found in the surveyed areas.
Population structure of the malaria vector Anopheles darlingi in Rond?nia, Brazilian Amazon, based on mitochondrial DNA
Angêlla, Aline F;Gil, Luis HS;Silva, Luis HP da;Ribolla, Paulo EM;
Memórias do Instituto Oswaldo Cruz , 2007, DOI: 10.1590/S0074-02762007000800010
Abstract: anopheles darlingi is the most important brazilian malaria vector, with a widespread distribution in the amazon forest. effective strategies for vector control could be better developed through knowledge of its genetic structure and gene flow among populations, to assess the vector diversity and competence in transmitting plasmodium. the aim of this study was to assess the genetic diversity of an. darlingi collected at four locations in porto velho, by sequencing a fragment of the nd4 mitochondrial gene. from 218 individual mosquitoes, we obtained 20 different haplotypes with a diversity index of 0.756, equivalent to that found in other neotropical anophelines. the analysis did not demonstrate significant population structure. however, haplotype diversity within some populations seems to be over-represented, suggesting the presence of sub-populations, but the presence of highly represented haplotypes complicates this analysis. there was no clear correlation among genetic and geographical distance and there were differences in relation to seasonality, which is important for malarial epidemiology.
Differential Annual Movement Patterns in a Migratory Species: Effects of Experience and Sexual Maturation
Paulo E. Jorge, David Sowter, Paulo A. M. Marques
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022433
Abstract: Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is thus a key factor in understanding migration patterns and differences in distribution ranges. In the present study, we investigated the effects of age on the geographic distribution of a population of Lesser Black-backed Gulls Larus fuscus throughout its annual cycle, by analyzing a dataset of 19,096 records from 10,000 color-ringed gulls. In contrast to previous assumptions, the results showed that gulls were geographically segregated by age throughout the entire annual cycle, rather than showing a geographic age-related cline only in the wintering areas. This asymmetric distribution results from a reduction in the annual range of sexually mature gulls, and the differential distribution of mature and immature individuals (mature birds remained in more northern areas, compared to immature birds, throughout the annual cycle). Furthermore, although immature gulls travelled longer distances than adults, they initiated their fall migration with short movements, in contrast to adults that migrated using longer movements. The effects identified in this study explain the non-homogenous distribution of populations throughout the annual cycle, with wide implications for the development of effective human health policies and/or wildlife management strategies.
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