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INTRODUCTION: Its wide karyotypic variation characterizes the genus Ctenomys, and in Brazil, the genus is distributed in the country's southern, Midwest, and northern regions. Recently, populations of Ctenomys have been found in the Midwest and northern Brazil, with two new lineages named C. sp. "xingu" and C. sp. "central." METHODS: This work combines classical cytogenetic and molecular analyses to provide new chromosomal information on the boliviensis group distributed in northern and Midwestern Brazil. This includes the validation of the karyotype of C. bicolor and C. nattereri and the description of the karyotype of C. sp. "xingu" and C. sp. "central." RESULTS: We found three different karyotypes: 2n = 40 for C. bicolor; 2n = 36 for C. nattereri, and specimens from a locality belonging to C. sp. "central"; 2n = 34 for the lineage C. sp. "xingu" and specimens from a locality belonging to C. sp. "central." Furthermore, GTG banding revealed homologous chromosomes between species/lineages and allowed the identification of the rearrangements that occurred, which proved the occurrence of fissions. CONCLUSION: Considering our results on the variation of 2n in the boliviensis group, we found two possibilities: the first, deduced by parsimony, is that 2n = 36 appeared initially, and two fissions produced gave rise to 2n = 40, and an independent fusion gave rise to 2n = 34 from 2n = 36; moreover, the second explanation is that all karyotypes arose independently.
Assuntos
Cariótipo , Roedores , Animais , Brasil , Roedores/genética , Roedores/classificação , Cariotipagem , Masculino , Bandeamento Cromossômico , Feminino , Cromossomos de Mamíferos/genética , FilogeniaRESUMO
BACKGROUND: The role of bats as reservoirs of zoonotic agents, especially pathogenic bacteria such as Bartonella and Coxiella, has been discussed around the world. Recent studies have identified bats as potential hosts of species from the proteobacteria phylum. In Brazil, however, the role of bats in the natural cycle of these agents is poorly investigated and generally neglected. In order to analyze the participation of bats in the epidemiology of diseases caused by Bartonella, Coxiella, Rickettsia, Anaplasma and Ehrlichia, we conducted a descriptive epidemiological study in three biogeographic regions of the Brazilian Atlantic Forest. RESULTS: Tissues of 119 bats captured in preserved areas in the states of Rio de Janeiro, Bahia and Santa Catarina from 2014 to 2015 were submitted to molecular analysis using specific primers. Bartonella spp. was detected in 22 spleen samples (18.5%, 95% CI: 11.9-26.6), whose phylogenetic analysis revealed the generation of at least two independent clusters, suggesting that these may be new unique genotypes of Bartonella species. In addition, four samples (3.4%, 95% CI: 0.9-8.3) were positive for the htpAB gene of C. burnetii [spleen (2), liver (1) and heart (1)]. Rickettsia spp., Anaplasma and Ehrlichia were not identified. This is the first study reporting C. burnetii and Bartonella spp. infections in bats from the Atlantic Forest biome. CONCLUSIONS: These findings shed light on potential host range for these bacteria, which are characterized as important zoonotic pathogens.
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Bartonella/isolamento & purificação , Quirópteros/microbiologia , Coxiella/isolamento & purificação , Animais , Bartonella/genética , Infecções por Bartonella/epidemiologia , Brasil/epidemiologia , Coxiella/genética , DNA Bacteriano , Feminino , Florestas , Bactérias Gram-Negativas , Masculino , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Baço/microbiologia , Zoonoses/epidemiologiaRESUMO
A new species of swamp rat of the genus Scapteromys from the Meridional Plateau of Southern Brazil is described. Morphological, molecular, and karyological analysis support the recognition of the new species, distinct from S. aquaticus and S. tumidus. Scapteromys sp. nov. is significantly smaller than the congeneric taxa considering most of the external and craniometric measurements and the pelage is conspicuously grayer and darker. It can be distinguished from S. tumidus by the laterally extended thenar pad of the manus and the parallel edges of the hamular process of the pterygoid, and from S. aquaticus by a grayer and darker pelage and smaller values of most external and craniometric measurements. Karyological analysis indicated a difference in chromosome numbers across the distributional range: 2n=34 and 2n=36. A total of 11 haplotypes were found along the range of the new species within the biogeographic province of Araucaria angustifolia Forest. Strongly supported substructure was found within the new taxon, resulting in two reciprocally monophyletic clades.
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Sigmodontinae/classificação , Animais , Brasil , Masculino , Filogenia , Sigmodontinae/anatomia & histologia , Sigmodontinae/genética , ÁrvoresRESUMO
Human Visceral Leishmaniasis is an endemic public health problem in the Amazon. This article analyzed the spatial distribution of this disease and its relationship with socioeconomic, environmental and public health policy variables in four mesoregions of the state of Pará, from 2011 to 2022. This ecological study used secondary data obtained from official Brazilian agencies. Spatial analysis was performed using the Flow, Kernel and Global Moran bivariate techniques expressed in thematic maps. In the mesoregions studied, 2685 cases of the disease were confirmed, with the highest number of cases in Southeast Pará state. The epidemiological profile followed the national pattern of occurrence of the disease, with a higher number of cases in children below school age. Spatial dependence was observed between the prevalence of the disease and socio-economic indicators. The most intense movement of patients was towards the Belém Metropolitan mesoregion. The disease showed an inhomogeneous pattern of distribution of cases, with a direct relationship between areas with cases and deforestation associated with different anthropic activities. There is a socio-environmental production of the disease that goes beyond the border limits of the mesoregions, and its establishment is related to the unsustainable development model implemented in the region.
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Histiotus are vespertilionid bats endemic to South America, easily recognized by its very long ears. During a twelve-month bat inventory in northeastern Brazil, eleven specimens of Histiotus were collected with a unique combination of characters that did not match those of any known species. In this paper, we describe these specimens as a new species. Histiotus sp. nov is distinguished from its congeners by its pale transparent wings and translucent ears, a triangular-shaped ear with a prominent lobe in the inner border connected by a band (~4 mm) across the forehead; its general golden-brownish body color and well-marked bicolor dorsal hairs. Its geographic distribution is unique among vespertilionids, arranged in a northeast-southwest diagonal across South America, includes the Caatinga and Cerrado of Brazil and Chaco of Bolivia. The available data suggest a seasonal reproductive pattern, with births occurring in the mid to late rainy season.
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Quirópteros/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Brasil , Quirópteros/anatomia & histologia , Quirópteros/crescimento & desenvolvimento , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Estações do AnoRESUMO
Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA(3) /DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA (3) /DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.
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Microchiropteran bats sustain very high oxygen consumption rates when active, but they also exhibit drastic daily drops in oxygen consumption when torpid. In addition, bats are also characterized by an extraordinary longevity considering their body mass and high specific metabolic rate when compared to other mammals of related size. Therefore, they consist of a very interesting group regarding the free radical theory of aging. The present study was carried out to measure the antioxidant defenses of several tissues of five South American bat species, attempting to correlate the antioxidant status, ecophysiology and longevity. Superoxide dismutase (SOD) and catalase (CAT) activities in blood, liver and kidney were higher compared to other tissues. The contents of alpha-tocopherol and beta-carotene found in liver, heart, kidneys, and pectoral muscles were one to two orders of magnitude higher than those usually found in rat and mouse liver. Also, these contents in liver were generally inversely related to lipoperoxidation measured as TBARS contents. Blood GSH contents and the activities of SOD and CAT were higher in torpid Sturnira lillium compared to active ones, thus suggesting that the elevation of such antioxidants might be daily modulated to minimize the oxidative stress related to the transition from torpid to active state in bats. The lower ROS generation reported in the literature for other bat species, their high constitutive antioxidant defenses, and the daily energy sparing associated with torpor appear to be closely related to their ecophysiological adaptations and to their extended longevity.
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Envelhecimento/fisiologia , Antioxidantes/metabolismo , Quirópteros/fisiologia , Ecossistema , Longevidade/fisiologia , Animais , Catalase/metabolismo , Rim/enzimologia , Peroxidação de Lipídeos , Fígado/enzimologia , Estresse Oxidativo , América do Sul , Superóxido Dismutase/metabolismo , alfa-Tocoferol/metabolismo , beta Caroteno/metabolismoRESUMO
Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA3/DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA3/DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.
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Animais , Análise Citogenética , Região Organizadora do Nucléolo , Roedores/genética , Brasil , Cariotipagem , FilogeniaRESUMO
Iraras apresentam variações de coloração por toda sua área de distribuição, sendo o objetivo deste estudo contribuir para o conhecimento destas variações. Na Reserva Biológica Estadual do Sassafrás, Santa Catarina, Brasil, foram obtidos 21 registros fotográficos de iraras, abrangendo diferentes colorações de pelagem. Duas classes de coloração foram observadas entre os indivíduos fotografados: corpo escuro com cabeça e pescoço cinzas e corpo, cabeça e pescoço branco-amarelados. A freqüência dos registros não variou significativamente entre as duas classes de coloração, indicando que a coloração de pelagem branco-amarelada é comum para esta população local.
Tayras present color variations along their range of distribution. The objective of this study is to contribute to the understanding of these variations. In the State Biological Reserve of Sassafrás, Santa Catarina, Brazil, 21 photographic records of tayras were obtained, comprising different coat colors. Two coat color classes were observed among photographed individuals: dark body with gray head and neck, and body, head and neck homogeneously white-yellowish. The frequency of records did not varied significantly between the two color classes, indicating that the white-yellowish coloration is common for this local population.