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Search Results: 1 - 10 of 490852 matches for " Paulo S. D'Andrea "
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Experimental evidence and ecological perspectives for the adaptation of Schistosoma mansoni Sambon, 1907 (Digenea: Schistosomatidae) to a wild host, the water-rat, Nectomys squamipes Brants, 1827 (Rodentia: Sigmodontinae)
D'Andrea, Paulo Sérgio;Fernandes, Fabiano Araujo;Cerqueira, Rui;Rey, Luis;
Memórias do Instituto Oswaldo Cruz , 2002, DOI: 10.1590/S0074-02762002000900003
Abstract: due to the semi aquatic habits and the overlap of the geographical distribution of the water-rat, nectomys spp., with schistosomiasis endemic areas, these wild rodents are very likely to acquire schistosoma mansoni infection in their daily activities. the role of the water-rat in the s. mansoni cycle would be substantiated if one could prove that these rodents acquire the parasite during their own activity time, a completely independent time schedule of human activities. to pursue this goal, we performed two field experiments in the municipality of sumidouro, state of rio de janeiro, brazil, a schistosomiasis endemic area where n. squamipes is found naturally infected. one experiment was devised as a series of observations of activity time of the water-rat. the other experiment was a test of the occurrence of late transmission of s. mansoni to the water-rat. the daily activity pattern showed that the water-rat is active chiefly just after sunset. at both diurnal and late exposition essays the water-rat sentinels got infected by s. mansoni. these findings clarify ecological and behavioral components necessary to the adaptation of s. mansoni to the water-rat as a non human definitive host and the existence of a transmission cycle involving this animals as a reservoir.
Experimental evidence and ecological perspectives for the adaptation of Schistosoma mansoni Sambon, 1907 (Digenea: Schistosomatidae) to a wild host, the water-rat, Nectomys squamipes Brants, 1827 (Rodentia: Sigmodontinae)
D'Andrea Paulo Sérgio,Fernandes Fabiano Araujo,Cerqueira Rui,Rey Luis
Memórias do Instituto Oswaldo Cruz , 2002,
Abstract: Due to the semi aquatic habits and the overlap of the geographical distribution of the water-rat, Nectomys spp., with schistosomiasis endemic areas, these wild rodents are very likely to acquire Schistosoma mansoni infection in their daily activities. The role of the water-rat in the S. mansoni cycle would be substantiated if one could prove that these rodents acquire the parasite during their own activity time, a completely independent time schedule of human activities. To pursue this goal, we performed two field experiments in the municipality of Sumidouro, State of Rio de Janeiro, Brazil, a schistosomiasis endemic area where N. squamipes is found naturally infected. One experiment was devised as a series of observations of activity time of the water-rat. The other experiment was a test of the occurrence of late transmission of S. mansoni to the water-rat. The daily activity pattern showed that the water-rat is active chiefly just after sunset. At both diurnal and late exposition essays the water-rat sentinels got infected by S. mansoni. These findings clarify ecological and behavioral components necessary to the adaptation of S. mansoni to the water-rat as a non human definitive host and the existence of a transmission cycle involving this animals as a reservoir.
Population ecology of small rodents and marsupials in a semi-deciduous tropical forest of the southeast Pantanal, Brazil
Andreazzi, Cecilia S. de;Rademaker, Vitor;Gentile, Rosana;Herrera, Heitor M.;Jansen, Ana M.;D'Andrea, Paulo S.;
Zoologia (Curitiba) , 2011, DOI: 10.1590/S1984-46702011000600009
Abstract: the pantanal is a south american biome characterized by extensive plains and stark environmental seasonality. several habitats are subject to annual flooding, forcing small mammal species to aggregate in dry forest patches, which most likely influences their population dynamics and life history strategies. in order to investigate the seasonal influence on the life history traits of these small mammals, we conducted a 2-year mark-recapture study in the southeastern region of the brazilian pantanal (nhecolandia) and analyzed the population dynamics of the most abundant small mammal species with the jackknife estimator. a trapping effort of 21,560 trap-nights resulted in 615 individuals in 1,171 captures (success = 5.43%). three species of rodents - oecomys mamorae (thomas, 1906), thrichomys pachyurus (wagner, 1845), and clyomys laticeps (thomas, 1841) - and three species of marsupials - gracilinanus agilis (burmeister, 1854), thylamys macrurus (olfers, 1818), and monodelphis domestica (wagner, 1842) - were obtained. the most abundant species was o. mamorae, followed by g. agilis and t. pachyurus. oecomys mamorae was more abundant in the wet season and presented an opportunistic reproductive strategy. gracilianus agilis displayed increased population sizes in the dry season and synchronized, seasonal reproduction during the rainy season. thrichomys pachyurus had a small population size, delayed response to variations in environmental conditions and higher reproductive rates in the dry season. all species revealed different life history strategies (seasonal, opportunistic or delayed response to environmental variations), coinciding with periods of higher resource availability in order to maximize survival.
Evidence of hantavirus infection in wild rodents captured in a rural area of the state of S?o Paulo, Brazil
Lemos, Elba Regina S. de;D'Andrea, Paulo S.;Bonvicino, Cibele R.;Famadas, Kátia M.;Padula, Paula;Cavalcanti, Adauto A.;Schatzmayr, Hermann G.;
Pesquisa Veterinária Brasileira , 2004, DOI: 10.1590/S0100-736X2004000200004
Abstract: hantaviruses are the etiological agents of the hantavirus cardio-pulmonary syndrome, a serious rodent-borne disease in brazil. in order to investigate the occurrence of hantavirus infection in wild rodents, a survey was conducted in three different suburban areas of the municipality of pedreira, state of s?o paulo, brazil. of the 145 wild animals captured belonging to 12 different species identified by morphology and karyological analysis, 107 were rodents of the following species: akodon montensis, bolomys lasiurus, calomys tener, oligoryzomys nigripes, oligoryzomys flavescens, and myocastor coypus. blood samples from these rodents were assayed for the presence of antibodies against hantavirus by igg elisa using andes recombinant nucleocapsid antigen. antibody reactive to andes virus was found in two different species, o. nigripes and o. flavescens. these results indicate a potential risk for hantavirus transmission to humans in this area, where reservoir rodents are present in peridomestic settings.
Maintenance and breeding of Thrichomys (Trouessart, 1880) (Rodentia: Echimyidae) in captivity
Teixeira, Bernardo Rodrigues;Roque, André Luiz R;Barreiros-Gómez, Simone Cristina;Borodin, Pavel Mikhailovitch;Jansen, Ana Maria;D'Andrea, Paulo Sérgio;
Memórias do Instituto Oswaldo Cruz , 2005, DOI: 10.1590/S0074-02762005000600005
Abstract: south american histricognath rodents thrichomys apereoides laurentius and thrichomys pachyurus are natural hosts of trypanosoma cruzi, agent of chagas disease. we established breeding colonies of these species to serve as experimental models in various parasitological studies. both species of thrichomys have all the requirements necessary to become excellent laboratory models: they can be easily maintained in the standard laboratory conditions and breed throughout the year and they do not have any special dietary demands and can be fed by standard food pellets designed for laboratory mice. both species produce precocious offspring that have their eyes and ears open, teeth erupted, fur well developed, and can eat solid food in the first week of life. t. a. laurentius has larger litter sizes and lower body masses at birth and weaning than t. pachyurus. moreover, females of t. a. laurentius reach puberty earlier and with lower body mass than t. pachyurus.
The Role of Historical Barriers in the Diversification Processes in Open Vegetation Formations during the Miocene/Pliocene Using an Ancient Rodent Lineage as a Model
Fabrícia F. Nascimento, Ana Lazar, Albert N. Menezes, Andressa da Matta Durans, Janio C. Moreira, Jorge Salazar-Bravo, Paulo S. DAndrea, Cibele R. Bonvicino
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061924
Abstract: The Neotropics harbors a high diversity of species and several hypotheses have been proposed to account for this pattern. However, while species of forested domains are frequently studied, less is known of species from open vegetation formations occupying, altogether, a larger area than the Amazon Forest. Here we evaluate the role of historical barriers and the riverine hypothesis in the speciation patterns of small mammals by analyzing an ancient rodent lineage (Thrichomys, Hystricomorpha). Phylogenetic and biogeographic analyses were carried out with mitochondrial and nuclear DNA markers to analyze the evolutionary relationships between Thrichomys lineages occurring in dry domains along both banks of the Rio S?o Francisco. This river is one of the longest of South America whose course and water flow have been modified by inland tectonic activities and climate changes. Molecular data showed a higher number of lineages than previously described. The T. inermis species complex with 2n = 26, FN = 48 was observed in both banks of the river showing a paraphyletic arrangement, suggesting that river crossing had occurred, from east to west. A similar pattern was also observed for the T. apereoides complex. Thrichomys speciation occurred in Late Miocene when the river followed a different course. The current geographic distribution of Thrichomys species and their phylogenetic relationships suggested the existence of frequent past connections between both banks in the middle section of the Rio S?o Francisco. The extensive palaeodune region found in this area has been identified as a centre of endemism of several vertebrate species and is likely to be a center of Thrichomys diversification.
Distinct Leishmania Species Infecting Wild Caviomorph Rodents (Rodentia: Hystricognathi) from Brazil
Renata Cássia-Pires,Mariana C. Boité,Paulo S. D'Andrea,Heitor M. Herrera,Elisa Cupolillo,Ana Maria Jansen,André Luiz R. Roque
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003389
Abstract: Background Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized. Methodology We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents. Principal findings In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting. Conclusions/Significance The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the “tip of the iceberg.”
An ecological field study of the water-rat Nectomys squamipes as a wild reservoir indicator of Schistosoma mansoni transmission in an endemic area
Gentile, Rosana;Costa-Neto, Sócrates F;Gon?alves, Margareth ML;Bonecker, Simone T;Fernandes, Fabiano A;Garcia, Juberlan S;Barreto, Magali G M;Soares, Marisa S;D'Andrea, Paulo S;Peralta, José M;Rey, Luis;
Memórias do Instituto Oswaldo Cruz , 2006, DOI: 10.1590/S0074-02762006000900018
Abstract: small mammals are found naturally infected by schistosoma mansoni, becoming a confounding factor for control programs of schistosomiasis in endemic areas. the aims of this study were: to investigate the infection rates by s. mansoni on the water-rat nectomys squamipes during four years in endemic areas of sumidouro, state of rio de janeiro, using mark-recapture technique; to compare two diagnostic methods for schistosomiasis; and to evaluate the effects of the chemotherapy in the human infected population on the rodent infection rates. the rodent infection rates of s. mansoni increased when rodent population sizes were lower. coprology and serology results presented the same trends along time and were correlated. serology could detect recent infection, including the false negatives in the coprology. the chemotherapy in the humans could not interrupt the rodent infection. rodents can increase the schistosomiaisis transmission where it already exists, they probably maintain the transmission cycle in the nature and can be considered as biological indicators of the transmission sites of this parasite since they are highly susceptible to infection. the water-rats may present different levels of importance in the transmission dynamics of s. mansoni infection cycle for each area, and can be considered important wild-reservoirs of this human disease.
Laccases stabilization with phosphatidylcholine liposomes  [PDF]
Meritxell Martí, Andrea Zille, Artur Cavaco-Paulo, José Luís Parra, Luisa Coderch
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.31010
Abstract: In recent years, there has been an upsurge of interest in enzyme treatment of textile fibres. Enzymes are globular proteins whose catalytic function is due to their three dimensional structure. For this reason, stability strategies make use of compounds that avoid dismantling or distorting protein 3D structures. This study is concerned with the use of microencapsulation techniques to optimize enzyme stabilization. Laccases were embedded in phophatidylcholine liposomes and their encapsulation capacity was assessed. Their enzymatic activity and stability were analyzed, comparing free-enzymes, enzymes in liposomes, and the lipid fraction separated from the aqueous fraction. An increase in their encapsulation efficiency was found at higher lipid/laccase ratios. Relative activity of enzyme-containing vesicles has also been shown to be retained much more than that of free native enzymes. The loss of activity of laccases entrapped in the vesicles in the total stability process is lower than 10% compared with 40% to 60% of loss of free-laccases after heating the samples for 3 days. Laccase stabilization could be of interest to future textile or cosmetic applications because of their potential for environmentally friendly oxidation technologies.
Detection of the first incidence of Akodon paranaensis naturally infected with the Jabora virus strain (Hantavirus) in Brazil
Oliveira, Renata Carvalho de;Guterres, Alexandro;Schrago, Carlos Guerra;Fernandes, Jorlan;Teixeira, Bernardo Rodrigues;Zeccer, Suzana;Bonvicino, Cibele R;D'Andrea, Paulo Sérgio;Lemos, Elba Regina Sampaio de;
Memórias do Instituto Oswaldo Cruz , 2012, DOI: 10.1590/S0074-02762012000300020
Abstract: we characterised hantaviruses circulating in different akodon rodent species collected in midwestern santa catarina (sc), southern brazil, where the jabora hantavirus (jabv) strain was first identified in akodon montensis. genetic and phylogenetic analyses based on a partial s segment indicated that, in sc, akodon paranaensis and a. montensis carried the same type of hantavirus. additionally, we conducted the first genomic characterisation of the complete s segment from the brazilian jabv strain. this is the first report of a. paranaensis infected with the jabv.
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