A estrutura do fígado de micos-leões de cativeiro (Callithrichidae, Primates): uma abordagem estereológica

Estudos sobre a morfologia e estereologia hepática são relevantes em pesquisa de anatomia e patologia comparada. Estes também facilitam o uso de primatas não-humanos como modelos experimentais em pesquisa básica, fato que tem auxiliado os estudos em medicina humana. Estudos quantitativos de estruturas hepáticas também têm sido mais prevalentes em Primatas do Velho Mundo e outros vertebrados. Foram estudados vinte e três fígados de micos-leões adultos, sendo : 06 Leontopithecus rosalia, 07 Leontopithecus chrysomelas e 10 Leontopithecus chrysopygus, os quais foram dissecados e fixados com formol tamponado a 10%. Para a quantificação estereológica, o fígado foi considerado como consistindo de parênquima (hepatócitos) e estroma (não-hepatócitos). O parâmetro estereológico densidade de volume (Vv) foi determinado por contagem de pontos, utilizando-se do sistema teste M42. As diferenças estereológicas hepáticas entre as três espécies de micos-leões não foram estatisticamente significativas. Portanto, um valor único de V V [hepatócito] e Vv [estroma] podem ser determinados como 96, 2% e 7,4%, respectivamente. Significantemente diferente, os valores encontrados para o V V [hepatócito] em micos-leões foram 0,09 vez maior do que em babuínos, e 0,17 em humanos. Contudo, o Vv [estroma] foi 1,04 vez menor do que o de babuínos e 1,79 vez menor do que o de humanos. As diferenças encontradas entre as proporções estudadas, mesmo que não comprovadas estatisticamente, mostram a necessidade de estudos futuros para correlacionar os aspectos morfo-fisiológicos destes micos.Studies on liver morphology and stereology are relevant to the comparative anatomical and pathological research. They also facilitate the use of nonhuman primates in basic research, which has substantially supported studies in human medicine. Quantitative studies of liver structures have also been more extensive in Old World primates and other vertebrates. Twenty-three livers of adult lion tamarins were studied (06 Leontopithecus rosalia, 07 Leontopithecus chrysomelas, and 10 Leontopithecus chrysopygus), dissected, and fixed in 10% neutral buffered formalin solution. For stereological quantification, the liver was regarded as consisting of parenchyma (hepatocytes) and stroma (nonhepatocytes). The stereologic parameter volume density (Vv) was determined by point counting, using M42 test-system. Hepatic stereological differences among the three species of lion tamarins were not statistically significant. Therefore, the pooled V V [hepatocyte] and Vv [stroma] could be determined as 96.2% and 7.4%, respectively. Significantly different, the values found for V V [hepatocyte] in lion tamarins were 0.09 times greater than those in baboons, and 0.17 in man. However, the Vv [stroma] was 1.04 times smaller than that in baboons and 1.79 times smaller than that in man. The differences found among the rates studied, even if not proven statistically, point out to the need for further studies to correlate the morphological and physiological features of those tamarins

A comparative study of eleven protein systems in tamarins, genus Saguinus (Platyrrhini, Callitrichinae)

The genetic variability of six tamarin taxa, genus Saguinus, was analyzed comparatively using protein data from eleven systems coded by 15 loci. S. fuscicollis weddelli and S. midas midas were the most polymorphic taxa, and S. bicolor the least. The results of the phylogenetic analyses (UPGMA and neighbor-joining) and the genetic distances between taxa were generally consistent with their geographic and probable phylogenetic relationships. Analyses of the S. bicolor and S. midas populations suggested that they represent no more than three subspecies of a single species, S. midas, with the bicolor forms belonging to a single subspecies, S. midas bicolor. If supported by additional studies, this would have important implications for the conservation of the bicolor form, which is endangered with extinction. The genetic similarity of S. fuscicollis and S. mystax was also consistent with their geographical and morphological proximity, although more data from a larger number of taxa will be required before the taxonomic relationships within the genus can be defined.A variabilidade genética de seis taxa de tamarins, gênero Saguinus, foi analisada comparativamente usando-se dados protéicos de onze sistemas codificados por quinze loci. S. fuscicollis weddelli e S. midas midas foram os taxa mais polimórficos, enquanto S. bicolor foi o menos. Os resultados da análise filogenética (UPGMA e neighbor-joining) e as distâncias genéticas entre os taxa foram em geral consistentes com suas relações geográficas e filogenéticas. As análises das populações de S. bicolor e S. midas indicaram que eles podem representar não mais do que três subespécies de uma única espécie, S. midas, com as formas de bicolor pertencendo a uma única subespécie, S. midas bicolor. Se apoiado por estudos adicionais, este fato teria implicações importantes para a conservação da forma de bicolor, que está em perigo de extinção. A similaridade genética de S. fuscicollis e S. mystax foi também consistente com sua proximidade geográfica e morfológica, embora mais dados sobre um número maior de taxa seriam necessários antes de se definirem as relações taxonômicas dentro do gênero

Survey of Plasmodium in the golden-headed lion tamarin (Leontopithecus chrysomelas) living in urban Atlantic forest in Rio de Janeiro, Brazil

Abstract Background Communicating the presence of potential zoonotic pathogens such as Plasmodium spp. in wild animals is important for developing both animal and human health policies. Methods The translocation of an exotic and invasive population of Leontopithecus chrysomelas (golden-headed lion tamarins) required the screening of these animals for specific pathogens. This studies objective was to investigate Plasmodium spp. infection in the L. chrysomelas, both to know its prevalence in these animals in the local area and to minimize the risk of pathogens being translocated to the destination site. To investigate Plasmodium spp. infection, blood samples from 268 animals were assessed for the presence of Plasmodium spp. by genus-specific PCR and stained thick and thin blood smears were examined by light microscopy. Data of human malaria infection in the studied region was also assembled from SINAN (Diseases Information System Notification—Ministry of Health of Brazil). Results Results from the PCR and microscopy were all negative and suggested that no L. chrysomelas was infected with Plasmodium spp. Analysis of SINAN data showed that malaria transmission is present among the human population in the studied region. Conclusions This study is the first to provide information on Plasmodium spp. infection in L. chrysomelas. Plasmodium spp. infection of this species is rare or absent though malaria parasites circulate in the region. In addition, there is minimal risk of translocating Plasmodium spp. infected animals to the destination site

Contrasting patterns of RUNX2 repeat variations are associated with palate shape in phyllostomid bats and New World primates

Establishing the genetic basis that underlies craniofacial variability in natural populations is one of the main topics of evolutionary and developmental studies. One of the genes associated with mammal craniofacial variability is RUNX2, and in the present study we investigated the association between craniofacial length and width and RUNX2 across New World bats (Phyllostomidae) and primates (Catarrhini and Platyrrhini). Our results showed contrasting patterns of association between the glutamate/alanine ratios (Q/A ratio) and palate shape in these highly diverse groups. In phyllostomid bats, we found an association between shorter/broader faces and increase of the Q/A ratio. In New World monkeys (NWM) there was a positive correlation of increasing Q/A ratios to more elongated faces. Our findings reinforced the role of the Q/A ratio as a flexible genetic mechanism that would rapidly change the time of skull ossification throughout development. However, we propose a scenario in which the influence of this genetic adjustment system is indirect. The Q/A ratio would not lead to a specific phenotype, but throughout the history of a lineage, would act along with evolutionary constraints, as well as other genes, as a facilitator for adaptive morphological changes.Fil: Ferraz, Tiago. Universidade Federal do Rio Grande do Sul; Brasil. Universidade de Sao Paulo; BrasilFil: Rossoni, Daniela M.. Universidade de Sao Paulo; BrasilFil: Althoff, Sérgio L.. Universidade Regional de Blumenau; BrasilFil: Pissinatti, Alcides. Universidade Federal da Bahia; BrasilFil: Paixão Cortês, Vanessa R.. Centro de Primatologia do Rio de Janeiro; BrasilFil: Bortolini, María Cátira. Universidade Federal do Rio Grande do Sul; BrasilFil: González José, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Marroig, Gabriel. Universidade de Sao Paulo; BrasilFil: Salzano, Francisco M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Gonçalves, Gislene L.. Universidad de Tarapacá de Arica; Chile. Universidade Federal do Rio Grande do Sul; BrasilFil: Hünemeier, Tábita. Universidade de Sao Paulo; Brasi

The gut microbiome of exudivorous marmosets in the wild and captivity

Mammalian captive dietary specialists like folivores are prone to gastrointestinal distress and primate dietary specialists suffer the greatest gut microbiome diversity losses in captivity compared to the wild. Marmosets represent another group of dietary specialists, exudivores that eat plant exudates, but whose microbiome remains relatively less studied. The common occurrence of gastrointestinal distress in captive marmosets prompted us to study the Callithrix gut microbiome composition and predictive function through bacterial 16S ribosomal RNA V4 region sequencing. We sampled 59 wild and captive Callithrix across four species and their hybrids. Host environment had a stronger effect on the gut microbiome than host taxon. Wild Callithrix gut microbiomes were enriched for Bifidobacterium, which process host-indigestible carbohydrates. Captive marmoset guts were enriched for Enterobacteriaceae, a family containing pathogenic bacteria. While gut microbiome function was similar across marmosets, Enterobacteriaceae seem to carry out most functional activities in captive host guts. More diverse bacterial taxa seem to perform gut functions in wild marmosets, with Bifidobacterium being important for carbohydrate metabolism. Captive marmosets showed gut microbiome composition aspects seen in human gastrointestinal diseases. Thus, captivity may perturb the exudivore gut microbiome, which raises implications for captive exudivore welfare and calls for husbandry modifications

The genome of the zoonotic malaria parasite Plasmodium simium reveals adaptations to host switching

BACKGROUND: Plasmodium simium, a malaria parasite of non-human primates (NHP), was recently shown to cause zoonotic infections in humans in Brazil. We sequenced the P. simium genome to investigate its evolutionary history and to identify any genetic adaptions that may underlie the ability of this parasite to switch between host species. RESULTS: Phylogenetic analyses based on whole genome sequences of P. simium from humans and NHPs reveals that P. simium is monophyletic within the broader diversity of South American Plasmodium vivax, suggesting P. simium first infected NHPs as a result of a host switch of P. vivax from humans. The P. simium isolates show the closest relationship to Mexican P. vivax isolates. Analysis of erythrocyte invasion genes reveals differences between P. vivax and P. simium, including large deletions in the Duffy-binding protein 1 (DBP1) and reticulocyte-binding protein 2a genes of P. simium. Analysis of P. simium isolated from NHPs and humans revealed a deletion of 38 amino acids in DBP1 present in all human-derived isolates, whereas NHP isolates were multi-allelic. CONCLUSIONS: Analysis of the P. simium genome confirmed a close phylogenetic relationship between P. simium and P. vivax, and suggests a very recent American origin for P. simium. The presence of the DBP1 deletion in all human-derived isolates tested suggests that this deletion, in combination with other genetic changes in P. simium, may facilitate the invasion of human red blood cells and may explain, at least in part, the basis of the recent zoonotic infections