ABSTRACT
The DARC (Duffy antigen receptor for chemokines) gene encodes the DARC protein, which serves multiple roles in the immune system, as a binding site for the malarial parasites Plasmodium vivax and Plasmodium knowlesi, a promiscuous chemokine receptor and a blood group antigen. Variation in DARC may play particularly significant roles in innate immunity, immunotolerance and pathogen entry in callitrichines, such as the black lion tamarin (Leontopithecus chrysopygus). We compared amino acid sequences of DARC in the black lion tamarin (BLT) to non-human Haplorhine primates and Homo sapiens. Consistent with prior studies in other Haplorhines, we observed that the chemokine receptor experiences two opposing selection forces: (1) positive selection on the Plasmodium binding site and (2) purifying selection. We observed also that D21N, F22L, and V25L differentiated BLT from humans at a critical site for P. vivax and P. knowlesi binding. One amino acid residue, F22L, was subject to both positive selection and fixation in New World monkeys, suggesting a beneficial role as an adaptive barrier to Plasmodium entry. Unlike in humans, we observed no variation in DARC among BLTs, suggesting that the protein does not play a role in immunotolerance. In addition, lion tamarins differed from humans at the blood compatibility Fya /Fyb antigen-binding site 44, as well as at the putative destabilizing residues A61, T68, A187, and L215, further supporting a difference in the functional role of DARC in these primates compared with humans. Further research is needed to determine whether changes in the Plasmodium and Fya /Fyb antigen-binding sites disrupt DARC function in callitrichines.
Subject(s)
Disease Susceptibility , Duffy Blood-Group System , Leontopithecus , Animals , Chemokines , Humans , Primates , Receptors, Cell SurfaceABSTRACT
The black lion tamarin, Leontopithecus chrysopygus, is endemic to the Atlantic Forest of the interior of the state of São Paulo in Brazil. Since the discovery of the species, authors have described variations in the pelage of L. chrysopygus, but the nature of this variation has remained unknown. We examined museum specimens and living animals to see if the pelage of L. chrysopygus varies individually, geographically or ontogenetically. We reviewed all known locality records of the species, and concluded that the pelage of L. chrysopygus varies individually and ontogenetically, but not geographically. The extent of the golden chromogenetic fields is larger in younger individuals, and the pelage becomes darker after successive moults. We examined 2 juveniles that presented a pelage similar to adult L. caissara. Geographically, there is a clear break in the phenotypes attributed to L. caissara and L. chrysopygus, precluding clinal variation and corroborating the specific status of the former. The separation between these 2 species is coincident with a tectonic fault known as the 'Guapiara lineament', and may have been caused by a recent activation of this geological formation. We also suggest a historical contact zone between L. chrysopygus and the marmoset Callithrix aurita in the upper Rio Tietê region.
Subject(s)
Geography , Hair/anatomy & histology , Leontopithecus/anatomy & histology , Pigmentation , Age Factors , Animals , Brazil , Female , Leontopithecus/classification , Male , PhylogenyABSTRACT
The critically endangered black-faced lion tamarin, Leontopithecus caissara, has a restricted geographical distribution consisting of small mainland and island populations, each with distinct habitats in coastal southeastern Brazil. Necessary conservation management actions require an assessment of whether differences in habitats are reflected in use of space by the species. We studied two tamarin groups on the mainland at São Paulo state between August 2005 and March 2007, and compared the results with data from Superagui Island. Three home range estimators were used: minimum convex polygon (MCP), Kernel, and the new technique presented dissolved monthly polygons (DMP). These resulted, respectively, in home ranges of 345, 297, and 282 ha for the 12-month duration of the study. Spatial overlap of mainland groups was extensive, whereas temporal overlap was not, a pattern that indicates resource partitioning is an important strategy to avoid intraspecific competition. L. caissara large home ranges seem to be dynamic, with constant incorporation of new areas and abandonment of others through time. The main difference between mainland and island groups is the amount and variety of sleeping sites. A better understanding of the home range sizes, day range lengths, and territorial behavior of this species will aid in developing better management strategies for its protection. Additionally, the presented DMP protocol is a useful improvement over the MCP method as it results in more realistic home range sizes for wildlife species.
Subject(s)
Leontopithecus/physiology , Spatial Behavior , Animals , Brazil , Female , Geography , Male , Seasons , SleepABSTRACT
Poucos são os estudos sobre comunidades de mamíferos de maior porte em remanescentes de Mata Atlântica, apesar do importante papel deste grupo na manutenção da diversidade e de processos biológicos e da sua susceptibilidade à extinção em paisagens fragmentadas. O presente trabalho tem como objetivo o levantamento de espécies de mamíferos de maior porte presentes em um remanescente de Mata Atlântica próxima à cidade de São Paulo. O remanescente estudado é a Reserva Florestal do Morro Grande, com área de 10.870 ha, localizada no município de Cotia, SP. Sete áreas da Reserva foram amostradas utilizando duas metodologias: 1) amostragem em transecto linear e 2) parcelas de areia como armadilhas de pegadas. Outros registros diretos e indiretos da ocorrência de espécies do grupo também foram considerados. Foram observadas dezoito espécies, de sete ordens, classificadas em quatro categorias de dieta, sendo oito onívoras, cinco herbívoras, quatro frugívoras e apenas uma carnívora. O método de amostragem em transecto linear amostrou seis espécies de três ordens e as parcelas de areia registraram sete espécies de cinco ordens. As espécies menores, como o esquilo (Sciurus aestuans), o gambá (Didelphis aurita) e o tapiti (Sylvilagus brasiliense) foram as mais registradas e estavam presentes em quase todas as áreas amostradas. O predomínio de espécies menores e de espécies generalistas é um indício do alto grau de perturbação e do comprometimento da qualidade desta Reserva. Conclui-se que a Reserva Florestal do Morro Grande não é capaz de preservar a integridade da fauna de mamíferos de maior porte.
Large mammals are known to be important for the maintenance of biological processes and diversity and to be highly susceptible to extinction in fragmented landscapes. However, there are few studies focusing on the community of large mammals in Atlantic Forest remnants. This study aims at surveying large mammals in a remnant of Atlantic forest near to São Paulo. The studied area is the Morro Grande Forest Reserve (RFMG), with 10.870 ha, located in the municipality of Cotia, SP. Seven areas inside the RFMG were studied with two methodologies: 1) line transect sampling and 2) sand plots for footprint recording. Others records of mammal species were also considered. Eighteen species of seven orders were found in the Reserve and were classified in four dietary categories being eight omnivorous, five herbivore, four frugivores and just one carnivorous. The line transect sampling recorded six species of three orders and footprint sampling recorded seven species of five orders. The smaller species, as the squirrel (Sciurus aestuans), the opossum (Didelphis aurita) and the brazilian rabbit (Sylvilagus brasiliense), were the most frequently recorded, and they were present in almost all the study's areas. The prevalence of smaller species and, the presence of some generalist species, indicate the high degree of disturbance and the low quality of this Reserve. The Reserva Florestal do Morro Grande do not maintain the integrity of large mammal community.
