RESUMO
The nine-banded armadillo (Dasypus novemcinctus) is the most widespread xenarthran species across the Americas. Recent studies have suggested it is composed of four morphologically and genetically distinct lineages of uncertain taxonomic status. To address this issue, we used a museomic approach to sequence 80 complete mitogenomes and capture 997 nuclear loci for 71 Dasypus individuals sampled across the entire distribution. We carefully cleaned up potential genotyping errors and cross contaminations that could blur species boundaries by mimicking gene flow. Our results unambiguously support four distinct lineages within the D. novemcinctus complex. We found cases of mito-nuclear phylogenetic discordance but only limited contemporary gene flow confined to the margins of the lineage distributions. All available evidence including the restricted gene flow, phylogenetic reconstructions based on both mitogenomes and nuclear loci, and phylogenetic delimitation methods consistently supported the four lineages within D. novemcinctus as four distinct species. Comparable genetic differentiation values to other recognized Dasypus species further reinforced their status as valid species. Considering congruent morphological results from previous studies, we provide an integrative taxonomic view to recognise four species within the D. novemcinctus complex: D. novemcinctus, D. fenestratus, D. mexicanus, and D. guianensis sp. nov., a new species endemic of the Guiana Shield that we describe here. The two available individuals of D. mazzai and D. sabanicola were consistently nested within D. novemcinctus lineage and their status remains to be assessed. The present work offers a case study illustrating the power of museomics to reveal cryptic species diversity within a widely distributed and emblematic species of mammals.
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Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for Ehrlichia and Anaplasma infections in the rainforests of the Amazon biome of French Guiana. Through molecular genetics and metagenomics reconstruction, we observe a high indigenous biodiversity of infections circulating among humans, wildlife, and ticks inhabiting these ecosystems. Molecular typing identifies these infections as highly endemic, with a majority of new strains and putative species specific to French Guiana. They are detected in unusual rainforest wild animals, suggesting they have distinctive sylvatic transmission cycles. They also present potential health hazards, as revealed by the detection of Candidatus Anaplasma sparouinense in human red blood cells and that of a new close relative of the human pathogen Ehrlichia ewingii, Candidatus Ehrlichia cajennense, in the tick species that most frequently bite humans in South America. The genome assembly of three new putative species obtained from human, sloth, and tick metagenomes further reveals the presence of major homologs of Ehrlichia and Anaplasma virulence factors. These observations converge to classify health hazards associated with Ehrlichia and Anaplasma infections in the Amazon biome as distinct from those in the Northern Hemisphere.
Assuntos
Anaplasma , Animais Selvagens , Ehrlichia , Filogenia , Floresta Úmida , Carrapatos , Anaplasma/genética , Anaplasma/isolamento & purificação , Anaplasma/patogenicidade , Anaplasma/classificação , Ehrlichia/genética , Ehrlichia/isolamento & purificação , Ehrlichia/classificação , Humanos , Animais , Carrapatos/microbiologia , Animais Selvagens/microbiologia , Anaplasmose/microbiologia , Anaplasmose/epidemiologia , Anaplasmose/transmissão , Guiana Francesa , Ehrlichiose/microbiologia , Ehrlichiose/epidemiologia , Ehrlichiose/veterinária , Ehrlichiose/transmissão , Metagenômica/métodos , Genoma Bacteriano/genética , RNA Ribossômico 16S/genéticaRESUMO
We investigated a Q fever outbreak that occurred in an isolated area of the Amazon Rain Forest in French Guiana in 2014. Capybara fecal samples were positive for Coxiella burnetii DNA. Being near brush cutters in use was associated with disease development. Capybaras are a putative reservoir for C. burnetii.
Assuntos
Coxiella burnetii , Febre Q , Animais , Coxiella burnetii/genética , Surtos de Doenças , Guiana Francesa/epidemiologia , Febre Q/epidemiologia , Floresta Úmida , RoedoresRESUMO
DNA barcoding has become a standard method for species identification in taxonomically complex groups. An important step of the barcoding process is the construction of a library of voucher-based material that was properly identified by independent methods, free of inaccurate identification, and paralogs. We provide here a cytochrome oxidase I (mt-Co1) DNA barcode database for species of the genus Oligoryzomys, based on type material and karyotyped specimens, and anchored on the mitochondrial genome of one species of Oligoryzomys, O. stramineus. To evaluate the taxonomic determination of new COI sequences, we assessed species intra/interspecific genetic distances (barcode gap), performed the General Mixed Yule Coalescent method (GMYC) for lineages' delimitation, and identified diagnostic nucleotides for each species of Oligoryzomys. Phylogenetic analyses of Oligoryzomys were performed on 2 datasets including 14 of the 23 recognized species of this genus: a mt-Co1 only matrix, and a concatenated matrix including mt-Co1, cytochrome b (mt-Cytb), and intron 7 of the nuclear fibrinogen beta chain gene (i7Fgb). We recovered nuclear-mitochondrial translocated (Numts) pseudogenes on our samples and identified several published sequences that are cases of Numts. We analyzed the rate of non-synonymous and synonymous substitution, which were higher in Numts in comparison to mtDNA sequences. GMYC delimitations and DNA barcode gap results highlight the need for further work that integrate molecular, karyotypic, and morphological analyses, as well as additional sampling, to tackle persistent problems in the taxonomy of Oligoryzomys.
Assuntos
Arvicolinae/genética , Núcleo Celular/genética , Código de Barras de DNA Taxonômico , Bases de Dados Genéticas , Genoma Mitocondrial/genética , Dinâmica Mitocondrial/genética , Animais , Especificidade da EspécieRESUMO
Abstract: Postnatal growth and development of the small Neotropical mouse Oecomys rutilus (Sigmodontinae: Cricetidae) were investigated from birth to day 143, in the laboratory. Morphometric measurements at age of 3 days, of both sexes combined, revealed body weight to be 3.4 ± 0.3 g, mean tail length as 27.4 ± 1.1 mm, and mean hind foot length as 9.3 ± 0.7 mm. Body weight was found to increase steadily until at least 69 days, whereas the instantaneous growth rates of other measurements declined earlier: the daily growth of hind foot length declined to a minimum at age of 24 days, and the growth of tail and of ear declined by the age of 33 days. Average litter size for 12 captive births was 2.5, ranging from 2 to 3. The preserved eye crystalline lens was weighted in 23 captive-born animals of known age, allowing a rough estimate of the age of reproduction in wild-caught animals. Based on the inferred relation between eye-lens weight and age, the youngest reproductive (pregnant) wild-caught females had an estimated age of 90 and 95 days.
Resumo: O crescimento pós-natal e o desenvolvimento do pequeno roedor neotropical Oecomys rutilus (Sigmodontinae: Cricetidae) foram investigados desde o nascimento até o dia 143, em laboratório. Mensurações morfométricas na idade de 3 dias, de ambos os sexos combinados, revelaram a massa corporal de 3,4 ± 0,3 g, comprimento médio da cauda de 27,4 ± 1,1 mm, e comprimento médio do pé de 9,3 ± 0,7 mm. A massa do corpo aumentou rapidamente até o dia 69, enquanto as taxas de crescimento instantâneo de outras medidas diminuíram mais cedo: o crescimento diário do pé diminuiu para o mínimo na idade de 24 dias, e os crescimentos da cauda e da orelha diminuíram na idade de 33 dias. O tamanho de prole médio para 12 nascimentos em cativeiro foi de 2,5, variando de 2 a 3. As lentes preservadas do cristalino do olho foram pesadas em 23 animais nascidos em cativeiro de idades conhecidas, permitindo fazer uma estimativa da idade de reprodução em animais capturados na natureza. Baseado na relação inferida entre peso da lente do cristalino e idade, as mais jovens fêmeas (prenhes) capturadas na natureza tiveram uma estimativa de 90 a 95 dias de idade.
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Abstract: Recent field surveys of bats (Chiroptera) in various localities of French Guiana have been accompanied by the collection and preservation of ectoparasites, mainly bat flies (Diptera: Streblidae and Nycteribiidae). Most specimens of ectoparasites was collected haphazardly during the course of bats inventories, but systematic surveys on the whole chiropteran community were realized at five opportunities. Concerning Streblidae, 813 individuals have been examined, which represent 46 species and/or subspecies belonging to 15 genera and 6 taxa for confirmation and/or future description. For Nycteribiidae, 44 individuals of 3 identified species and 2 for confirmation and/or future description. Other ectoparasites have been found (Hemiptera and acarids), which are also listed with details on their bat-host, place and date of collect. For six species of bats in which at least 10 animals were carrying ectoparasites, a brief description of the frequencies of their ectoparasites provides some preliminary characteristics of their infracommunities.
Resumo: Pesquisas de campo recentes de morcegos (Chiroptera) em várias localidades da Guiana Francesa foram acompanhadas pela coleta e preservação de ectoparasitas, principalmente moscas ectoparasitas (Diptera: Streblidae e Nycteribiidae). A maioria dos espécimes de ectoparasitos foi coletada aleatoriamente durante o curso dos inventários de morcegos, mas pesquisas sistemáticas em toda a comunidade de quirópteros foram realizadas em cinco oportunidades. Sobre Streblidae, 813 indivíduos foram examinados, dos quais representam 46 espécies e/ou subespécies pertencentes a 15 gêneros e 6 táxons para posterior confirmação específica e/ou descrição. Para Nycterbiidae, 44 indivíduos de 3 espécies e 2 para posterior confirmação específica e/ou descrição. Outros ectoparasitos foram coletados (hemípteros polictenídeos e ácaros), os quais também foram listados com detalhes sobre seus hospedeiros, localidade e data de coleta. Para seis espécies de morcegos com mais de 10 morcegos infestados a descrição da composição de cada infracomunidade encontrada e sua frequência são apresentados.
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The spiny rats, genus Proechimys, have the highest species richness within the Echimyidae family, as well as species with high genetic variability. The genus distribution includes tropical South America and Central America south to Honduras. In this study, we evaluate the phylogeographic histories of Proechimys guyannensis and P. cuvieri using cytochrome b, in a densely sampled area in northeastern Amazon where both species are found in sympatry in different environments. For each species, Bayesian and Maximum Likelihood phylogenetic analysis were congruent and recovered similar clades in the studied area. Bayesian phylogenetic analysis using a relaxed molecular clock showed that these clusters of haplotypes diversified during Pleistocene for both species. Apparently, the large rivers of the region did not act as barriers, as some clades include specimens collected from opposite banks of Oiapoque, Araguari and Jari rivers. Bayesian skyline plot analysis showed recent demographic expansion in both species. The Pleistocene climatic changes in concert with the geologic changes in the Amazon fan probably acted as drivers in the diversification that we detected in these two spiny rats. Proechimys cuvieri and P. guyannensis show genetic structure in the eastern part of the Guiana region. Greater genetic distances observed in P. guyannensis, associated with highly structured groups, suggest that more detailed studies of systematics and ecology should be directed to this species.
Assuntos
Mudança Climática , Citocromos b/genética , Variação Genética , Haplótipos , Filogenia , Roedores/genética , Animais , Brasil , RiosAssuntos
Biodiversidade , Conservação dos Recursos Naturais/legislação & jurisprudência , Política Ambiental/legislação & jurisprudência , Ouro/isolamento & purificação , Mineração , Floresta Úmida , Animais , Conservação dos Recursos Naturais/tendências , Política Ambiental/tendências , Guiana Francesa , ParisRESUMO
In the current context of global change and human-induced biodiversity decline, there is an urgent need for developing sampling approaches able to accurately describe the state of biodiversity. Traditional surveys of vertebrate fauna involve time-consuming and skill-demanding field methods. Recently, the use of DNA derived from invertebrate parasites (leeches and blowflies) was suggested as a new tool for vertebrate diversity assessment. Bloodmeal analyses of arthropod disease vectors have long been performed to describe their feeding behaviour, for epidemiological purposes. On the other hand, this existing expertise has not yet been applied to investigate vertebrate fauna per se. Here, we evaluate the usefulness of hematophagous dipterans as vertebrate samplers. Blood-fed sand flies and mosquitoes were collected in Amazonian forest sites and analysed using high-throughput sequencing of short mitochondrial markers. Bloodmeal identifications highlighted contrasting ecological features and feeding behaviour among dipteran species, which allowed unveiling arboreal and terrestrial mammals of various body size, as well as birds, lizards and amphibians. Additionally, lower vertebrate diversity was found in sites undergoing higher levels of human-induced perturbation. These results suggest that, in addition to providing precious information on disease vector host use, dipteran bloodmeal analyses may represent a useful tool in the study of vertebrate communities. Although further effort is required to validate the approach and consider its application to large-scale studies, this first work opens up promising perspectives for biodiversity monitoring and eco-epidemiology.
Assuntos
DNA/sangue , Insetos Vetores/genética , Vertebrados/classificação , Animais , Biodiversidade , Culicidae/genética , Comportamento Alimentar , Guiana Francesa , Psychodidae/genéticaRESUMO
Among mammals, rodents play a key role in the emergence of viral diseases. In French Guiana, with 36 rodent species recorded in various ecosystems (pristine forests, savannas, anthropized environments), some natural habitats today encounter anthropogenic perturbations that induce changes in community structure and population dynamics. These modifications are sometimes associated with the circulation and emergence of viral pathogens. For 10 years, investigations on the circulation of two rodent-borne viruses, Hantavirus and Mammarenavirus, are underway in rodent populations as well as in humans for hantavirus. These investigations identified viruses from both genera in their potential reservoirs and allow describing the most favourable habitats for the reservoirs of hantavirus where the risk of viral emergence may be higher. We suggest to investigate how anthropic perturbations in rodent communities can drive the emergence of viruses that are currently confined to a small scale and search for evidence of infection in the human population.
RESUMO
Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp.
Assuntos
Enteropatias Parasitárias/veterinária , Doenças dos Roedores/parasitologia , Sigmodontinae/parasitologia , Trichostrongyloidea/isolamento & purificação , Tricostrongiloidíase/veterinária , Animais , DNA de Helmintos/genética , Feminino , Florestas , Guiana Francesa , Enteropatias Parasitárias/parasitologia , Intestino Delgado/parasitologia , Masculino , Especificidade da Espécie , Trichostrongyloidea/anatomia & histologia , Trichostrongyloidea/classificação , Trichostrongyloidea/genética , Tricostrongiloidíase/parasitologiaRESUMO
Thirty-seven house mice (Mus musculus, Rodentia) caught in different localities in French Guiana were screened to investigate the presence of lymphocytic choriomeningitis mammarenavirus (LCMV). Two animals trapped in an urban area were found positive, hosting a new strain of LCMV, that we tentatively named LCMV "Comou". The complete sequence was determined using a metagenomic approach. Phylogenetic analyses revealed that this strain is related to genetic lineage I composed of strains inducing severe disease in humans. These results emphasize the need for active surveillance in humans as well as in house mouse populations, which is a rather common rodent in French Guianese cities and settlements.
Assuntos
Coriomeningite Linfocítica/veterinária , Vírus da Coriomeningite Linfocítica/classificação , Vírus da Coriomeningite Linfocítica/isolamento & purificação , Doenças dos Roedores/virologia , Animais , Guiana Francesa , Genoma Viral , Vírus da Coriomeningite Linfocítica/genética , Metagenômica/métodos , Camundongos , FilogeniaRESUMO
BACKGROUND: Myotis albescens occurs from Mexico southward to Uruguay and Argentina. The species is known for all South American countries except French Guiana and Chile. NEW INFORMATION: Based on one specimen recently collected in French Guiana we fill part of the gap in the distribution of the species in South America. Myotis albescens occurs in the Guiana Shield with other four congeners, from which it can be distinguished by external and skull traits. As an aid to future identifications, we provide a key to this assemblage.
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In this study, we quantitatively evaluated the spread of resistance to ß-lactams and of integrons in small rodents and marsupials living at various distances from a point of antibiotic's use. Rectal swabs from 114 animals were collected in Trois-Sauts, an isolated village in French Guiana, and along a 3 km transect heading through the non-anthropized primary forest. Prevalence of ticarcillin-resistant enterobacteria was 36% (41/114). Klebsiella spp., naturally resistant to ticarcillin, were found in 31.1% (23/73) of animals from the village and in an equal ratio of 31.7% (13/41) of animals trapped along the transect. By contrast Escherichia coli with acquired resistance to ticarcillin were found in 13.7% (10/73) of animals from the village and in only 2.4% (1/41) of those from the transect (600 m from the village). There was a huge diversity of E. coli and Klebsiella pneumoniae strains with very unique and infrequent sequence types. The overall prevalence of class 1 integrons carriage was 19.3% (22/114) homogenously distributed between animals from the village and the transect, which suggests a co-selection by a non-antibiotic environmental factor. Our results indicate that the anthropogenic acquired antibiotic resistance did not disseminate in the wild far from the point of selective pressure.
Assuntos
Animais Selvagens/microbiologia , Escherichia coli/efeitos dos fármacos , Transferência Genética Horizontal , Klebsiella pneumoniae/efeitos dos fármacos , Resistência beta-Lactâmica , Animais , Antibacterianos/farmacologia , Escherichia coli/isolamento & purificação , Florestas , Guiana Francesa , Klebsiella pneumoniae/isolamento & purificação , Marsupiais/microbiologia , Roedores/microbiologia , Seleção Genética , Ticarcilina/farmacologiaRESUMO
Molecular screening of rodents from French Guiana has detected a new arenavirus, named "Patawa," in two Oecomys species (Muridae, Sigmodontinae). Further investigations are needed to better understand the circulation of this virus in rodent and human populations and its public health impact.
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Infecções por Arenaviridae/epidemiologia , Infecções por Arenaviridae/veterinária , Arenavirus/isolamento & purificação , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/virologia , Animais , Sequência de Bases , Florestas , Guiana Francesa/epidemiologia , Sigmodontinae/virologiaRESUMO
The trichostrongylid nematode Travassostrongylus scheibelorum sp. n. from the Linnaeus' mouse opossum, Marmosa murina (Linnaeus) (type host), and the woolly mouse opossum, Marmosa demerarae (Thomas), from French Guiana is described. The nematodes have a synlophe with ridges frontally oriented from right to left, six dorsal and six ventral, at midbody; seven dorsal and seven ventral posterior to the vulva, and two cuticular thickenings within the lateral spaces; a long dorsal ray and a pointed cuticular flap covering the vulva. This is the 12th species of Travassostrongylus Orloff, 1933, which includes species featuring ridges around the synlophe and a didelphic condition. These traits contrast with those in other genera in the Viannaiidae Neveu-Lemaire, 1934, which feature ventral ridges on the synlophe of adults and a monodelphic condition. Members of the family are chiefly Neotropical and are diagnosed based on the presence of a bursa of the type 2-2-1, 2-1-2 or irregular, and cuticle without ridges on the dorsal side (at least during one stage of their development). Herein, we present a reconstruction of the ancestral states of the didelphic/monodelphic condition and the cuticular ridges that form the synlophe in opossum-dwelling trichostrongyles, namely Travassostrongylus and Viannaia Travassos, 1914. Our investigations suggest they are not reciprocal sister taxa and that the change from didelphy to monodelphy and the loss of dorsal ridges, occurred in the common ancestor of species of Viannaia. These results suggest a synlophe with three ventral ridges is not plesiomorphic in the opossum dwelling trichostrongylids.
Assuntos
Nematoides/anatomia & histologia , Nematoides/classificação , Infecções por Nematoides/veterinária , Gambás , Animais , Feminino , Guiana Francesa/epidemiologia , Masculino , Nematoides/genética , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Filogenia , Especificidade da EspécieRESUMO
A molecular screening of wild-caught rodents was conducted in French Guiana, South America to identify hosts of the hantavirus Maripa described in 2008 in a hantavirus pulmonary syndrome (HPS) case. Over a 9-year period, 418 echimyids and murids were captured. Viral RNA was detected in two sigmodontine rodents, Oligoryzomys fulvescens and Zygodontomys brevicauda, trapped close to the house of a second HPS case that occurred in 2009 and an O. fulvescens close to the fourth HPS case identified in 2013. Sequences from the rodents had 96% and 97% nucleotide identity (fragment of S and M segments, respectively) with the sequence of the first human HPS case. Phylogenetic reconstructions based on the complete sequence of the S segment show that Maripa virus is closely related to Rio Mamore hantavirus. Using environmental descriptors of trapping sites, including vegetation, landscape units, rain, and human disturbance, a maximal entropy-based species distribution model allowed for identification of areas of higher predicted occurrence of the two rodents, where emergence risks of Maripa virus are expected to be higher.
Assuntos
Anticorpos Antivirais/sangue , Síndrome Pulmonar por Hantavirus/epidemiologia , Orthohantavírus/isolamento & purificação , Doenças dos Roedores/epidemiologia , Animais , Sequência de Bases , DNA Complementar/química , DNA Complementar/genética , Demografia , Reservatórios de Doenças , Guiana Francesa/epidemiologia , Geografia , Orthohantavírus/classificação , Orthohantavírus/genética , Orthohantavírus/imunologia , Síndrome Pulmonar por Hantavirus/virologia , Humanos , Rim/virologia , Pulmão/virologia , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Doenças dos Roedores/virologia , Roedores , Análise de Sequência de DNARESUMO
In industrialized countries Candida albicans is considered the predominant commensal yeast of the human intestine, with approximately 40% prevalence in healthy adults. We discovered a highly original colonization pattern that challenges this current perception by studying in a 4- year interval a cohort of 151 Amerindians living in a remote community (French Guiana), and animals from their environment. The prevalence of C. albicans was persistently low (3% and 7% of yeast carriers). By contrast, Candida krusei and Saccharomyces cerevisiae were detected in over 30% of carriers. We showed that C. krusei and S. cerevisiae carriage was of food or environmental origin, whereas C. albicans carriage was associated with specific risk factors (being female and living in a crowded household). We also showed using whole-genome sequence comparison that C. albicans strains can persist in the intestinal tract of a healthy individual over a 4-year period.
Assuntos
Candida albicans/fisiologia , Intestinos/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Candida albicans/classificação , Candidíase/epidemiologia , Candidíase/microbiologia , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Evolução Molecular , Feminino , Guiana Francesa , Genoma Fúngico , Humanos , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Micoses/epidemiologia , Micoses/microbiologia , Filogenia , Prevalência , Leveduras/classificação , Leveduras/fisiologia , Adulto JovemRESUMO
We undertook a large-scale epidemiological survey of commensal Escherichia coli in Trois-Sauts, an isolated village located in the south of French Guiana where human population exchanges are restricted and source of antibiotics controlled. Stools from 162 Wayampi Amerindians and rectal swabs from 33 human associated and 198 wild animals were collected in the close proximity of the village. The prevalence of E. coli was decreasing from humans (100%) to human associated (64%) and wild (45%) animals. A clear genetic structure between these three E. coli populations was observed with human strains belonging very rarely to B2 phylogroup (3.7%), exhibiting few virulence genes and bacteriocins but being antibiotic resistant whereas wild animal strains were characterized by 46.1% of B2 phylogroup belonging, with very unique and infrequent sequence types, numerous extraintestinal genes and bacteriocins but no antibiotic resistance; the human-associated animal strains being intermediate. Furthermore, an unexpected genetic diversity was observed among the strains, as the housekeeping gene nucleotide diversity per site of the Trois-Sauts's strains was higher than the one of reference strains representative of the known species diversity. The existence of such E. coli structured phylogenetic diversity within various hosts of a single localization has never been reported.
Assuntos
Escherichia coli/isolamento & purificação , Variação Genética , Animais , Animais Selvagens , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , DNA Bacteriano/genética , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/classificação , Escherichia coli/genética , Escherichia coli/patogenicidade , Fezes/microbiologia , Guiana Francesa , Especificidade de Hospedeiro , Humanos , Filogenia , VirulênciaRESUMO
Squirrel monkeys (genus Saimiri) are distributed over a wide area encompassing the Amazon Basin: French Guiana, Suriname, and Guyana, together with Western Panama and Western Costa Rica. The genus Saimiri includes a complex of species and subspecies displaying considerable morphological variation. Taxonomic and systematic studies have identified, in this genus, one to seven species comprising up to 16 subspecies. The phylogenetic relationships between these taxa are poorly understood. Molecular markers have yielded a consistent framework for the systematics of Central and South American Saimiri, identifying four distinct clades: S. oerstedii, S. sciureus, S. boliviensis, and S. ustus. Here, we reconsider the phylogenetic and biogeographic history of Saimiri on the basis of mitochondrial (mtDNA) sequence data, focusing mostly on individuals originating from the Amazon Basin. We studied 32 monkeys with well-defined geographic origins and inferred the phylogenetic relationships between them on the basis of full-length cytochrome b gene nucleotide sequences. The high level of gene diversity observed (0.966) is consistent with the high level of behavioral and morphological variation observed across the geographic range of the genus: 20 mtDNA haplotypes were identified with a maximum divergence of 4.81% between S. b. boliviensis and S. ustus. In addition to confirming the existence of the four clades previously identified on the basis of molecular characters, we suggest several new lineages, including S. s. macrodon, S. s. albigena, S. s. cassiquiarensis, and S. s. collinsi. We also propose new patterns of dispersion and diversification for the genus Saimiri, and discuss the contribution of certain rivers and forest refuges to its structuring.