Classificação morfofuncional dos dentes de saguis-de-tufo-branco (Callithrix jacchus, Callitrichidae), saguis-de-tufo-preto (C. penicillata) e saguis-de-cara-branca (C. geoffroyi)

Realizou-se um estudo para analisar morfologicamente os dentes do saguis-de-tufo-branco (C. jacchus), saguis-de-tufo-preto (C. penicillata) e saguis-de-cara-branca (C. geoffroyi), para compara-los entre si e com outras espécies já descritas na literatura. Utilizou-se dentes das três espécies para analises macroscópicas, microscópicas e ultraestrutural e os resultados correlacionados com os obtidos com outras espécies citadas na literatura. Chegou-se a conclusão de que: as três espécies apresentaram uma fórmula dentária idêntica, chegando a um total de 32 dentes, expressa na fórmula 2x: incisivos 2/2; caninos 1/1; pré-molares 3/3 e molares 2/2, estes são classificados como diplodontes, anelodontes, bunodontes, e braquiodontes.

Cytogenetic study in natural hybrids of Callithrix (Callitrichidae: Primates) in the Atlantic forest of the state of Rio de Janeiro, Brazil

In the Atlantic forest of Rio de Janeiro, Callithrix aurita (É. Geoffroy in Humboldt, 1812) is a native species vulnerable to extinction and C. jacchus (Linnaeus, 1758) and C. penicillata (É. Geoffroy, 1812) are invasive species. The major threats to the native species are habitat degradation and hybridization, although there are currently no genetic data about natural hybrids available. Previous studies have revealed that species of the Callithrix genus are extremely homogeneous in their karyotypes with the exceptions of the morphology and size of the Y chromosome and its nucleolar organizer region (NOR) banding pattern. Three male marmosets captured in the wild in Guapimirim municipality, Rio de Janeiro, Brazil, considered as possible hybrids between C. aurita and C. jacchus or C. penicillata on the basis of pelage pattern, were cytogenetically studied. Metaphase chromosomes were obtained by using short-term lymphocyte cultures and Ag-NOR staining was performed. The hybrids karyotypes were 2n=46, 14 uni- and 30 bi-armed autosomes, a median size submetacentric X and NOR bearing autosomes, being compatible with that observed for the genus. In the three individuals studied, Y chromosomes were similar to those found for C. aurita, without NORs. The data obtained suggest the involvement of C. aurita in natural hybridization with one of the invasive species. We discuss the possible consequences of this hybridization.

Myocardial stereology in captive Callithrix kuhlii (Callitrichidae, Primates): healthy animals versus animals affected by wasting marmoset syndrome (WMS)

This study comprised 12 hearts of Wied´s black-tufted-ear marmoset, Callithrix kuhlii (Coimbra-Filho 1985), 6 with Wasting Marmoset Syndrome (WMS) and 6 non-affected. Biometry was performed after death. After necropsy, the hearts were weighed, dissected, fixed in 10% formalin solution (pH 7.2), and processed for optical microscopy at 5µm sections stained with Haematoxylin-Eosin. Quantitative analysis was performed by stereological techniques. The statistical differences between the biometrical and stereological parameters were assessed by the Mann-Whitney test. The morphometric results showed that WMS causes a significant reduction in body and cardiac weights, and also in the volume density of vessels in those animals. Further studies are necessary to understand some of the results shown here.

Distribution of collagen types I, III, and IV in gastric tissue of marmosets (Callithrix spp., Callitrichidae: Primates)

Extracellular matrix (ECM) components such as fibrillar collagens play a fundamental role in wound repair and have also been studied in association with the gastric ulcer healing process in gastroenterology. Nevertheless, there have been no studies in the literature to date regarding the description and characterization of ECM components, neither in normal nor in injured gastric tissue of primate species. The objective of this study was to investigate the expression of gastric collagen types I, III, and IV in marmosets (Callithrix sp.). Histological specimens from the stomach of 6 Callithrix jacchus, 12 C. kuhli, and 12 C. geoffroyi were evaluated. The specimens were immunostained with anti-types I and III collagen polyclonal antibodies and anti-type IV collagen monoclonal antibody. Collagen types I and III were detected in the submucosa and lamina propria between the mucosal glands while collagen type IV was detected in the muscularis mucosae, muscular layers, blood vessels, and gastric mucosa between the mucosal glands. It is hoped that these findings can contribute to future studies on the gastric extracellular matrix components in primates and to comparative studies in the area of gastroenterology.

Simian malaria in Brazil

In Brazil simian malaria is widely spread, being frequent in the Amazon region (10% of primates infected) and even more in the forested coastal mountains of the Southeastern and Southern regions (35% and 18% infected, respectively), but absent in the semi-arid Northeast. Only two species of plasmoidia have been found: the quartan-like Plasmodium brasilianum and the tertian-like P. simium, but the possible presence of other species is not excluded. P. brasilianum is found in all enzootic foci, but P. simium was detected only on the coast of the Southeastern and Southern regions, between parallels 20-S and 30-S. Nearly all hosts are monkeys (family Cebidae, 28 species harbouring plasmodia out of 46 examined) and very rarely marmosets or tamarins (family Callitrichidae, I especies out of 16). P. brasilianum was present in all infected species, P. simium in only two. The natural vector in the Southeastern and Southern regions was found to be Anopheles cruzi, but has not been conclusively identified in the Amazon. One natural, accidental human infection due to P. simium was observed. There is no evidence of the relation of the simian to human malaria in the Southeastern and Southern regions, where human malaria was eradicated in spite of the high rates of monkeys infected, but in the Amazon recent serological studies by other workers, revealing high positivity for P. brasilianum/P. malariae antibodies in local indians, would suggest that among them malaria might be regarded as a zoonosis.