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PubMed2005

Identification of Helicobacter sp. in gastric mucosa from captive marmosets (Callithrix sp.; callitrichidae, primates).

The aim of this study was to identify the presence of Helicobacter sp. in the gastric mucosa of captive marmosets (Callithrix sp.). Histologic specimens from the fundic, corpus, and antral gastric regions of six Callithrix jacchus, 12 C. kuhli, and 12 C. geoffroyi specimens were evaluated. The sections were stained with hematoxylin-eosin (H&E) and the Warthin-Starry silver impregnation method, and immunostained with rabbit anti-H. pylori polyclonal antibody. Helicobacter-like organisms (HLOs) and coccoid forms were present in silver-stained sections from 29 stomachs, whereas immunohistochemistry (IHC) tests revealed bacterial aggregates in 15 stomachs. No statistical difference relative to the presence of Helicobacter sp. was found among the gastric regions or marmoset species. Gastric lesions were found in the groups of marmosets that had positive and negative IHC results, but no correlation between inflammation and Helicobacter sp. infection was established. These findings demonstrate that marmosets are susceptible to naturally-occurring Helicobacter sp. infection, and open the way to the development of comparative studies on Helicobacter sp. infection in humans.

Animals↗

PubMed2006

Cross-genus adoption of a marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus): case report.

We report a case of interspecies adoption of an infant marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus). The marmoset was an infant when it was first observed in the capuchin group on 3 March 2004. Since it first appeared it has been observed informally and frequently. In January 2005 systematic observations were made of the marmoset and a capuchin of similar age. Throughout its period of adoption the marmoset appeared to be socially integrated into the group, benefiting from nurturant behaviors exhibited by two successive adoptive "mothers" and pronounced tolerance from all members of the group. This case highlights the flexibility of both Callithrix and Cebus in accommodating variable social behaviors and other characteristics (including size) of social partners.

Adoption↗

PubMed1992

Gummivory and gut morphology in two sympatric callitrichids (Callithrix emiliae and Saguinus fuscicollis weddelli) from western Brazilian Amazonia.

A comparative analysis of the gastrointestinal tracts of wild-caught marmosets, Callithrix emiliae, and tamarins, Saguinus fuscicollis weddelli, was undertaken in order to evaluate the degree of specialisation for digestion of plant exudates. Compared to S.f. weddelli, C. emiliae exhibits a reduced small intestine and a relatively large, compartmentalised caecum in which gum is probably fermented. The apparent specialisation of the digestive tract in C. emiliae correlates with that of its dentition, which is adapted for gouging the bark of gum-producing plants. A similar degree of specialisation of the caecum is predicted for other marmosets (Callithrix spp. and Cebuella pygmaea).

Animal Feed↗

PubMed1995

Morphology and connections of neurons in area 17 projecting to the extrastriate areas MT and 19DM and to the superior colliculus in the monkey Callithrix jacchus.

Neurons of area 17, the primary visual cortex, project to various anatomically and physiologically different extrastriate areas and subcortical regions. In the present investigation, we addressed the question of whether the efferent neurons in area 17 can contribute to functional diversity between these regions. We approached this question by analyzing the dendritic morphology of neurons in area 17 projecting to area MT, area 19DM, and the superior colliculus in the new world simian primate Callithrix jacchus, because dendritic morphology is an important factor in determining physiological properties of nerve cells. Retrograde transport of fluorochromes injected into the target regions, and intracellular injections of Lucifer yellow in the prelabelled neurons, revealed the following. 1) Morphologically identical large pyramidal cells in layer VI of area 17 project to all three targets. Some of them possess axon collaterals to two or all three targets, suggesting that they provide common information to all three areas. 2) Pyramidal cells in layer IIIc projecting to area MT form a morphologically homogeneous population. 3) Three small to medium-sized pyramidal cell types in layers IIIa-c, spiny stellate cells in layer IIIc, and another large pyramidal cell type in layer VI project to area 19DM. 4) Pyramidal cells in the lower two-thirds of layer V in area 17 project to the superior colliculus. In conclusion, we have shown that in Callithrix one efferent pathway may originate from several cell types. However, with the exception of the large cells in layer VI, efferent cells projecting to area MT, area 19DM, and the superior colliculus were morphologically distinct. This suggests that functional differences between brain regions could arise in part from morphological heterogeneity between and within the efferent cell populations.

Animals↗

PubMed2004

Comparative analysis of masseter fiber architecture in tree-gouging (Callithrix jacchus) and nongouging (Saguinus oedipus) callitrichids.

Common marmosets (Callithrix jacchus) and cotton-top tamarins (Saguinus oedipus) (Callitrichidae, Primates) share a broadly similar diet of fruits, insects, and tree exudates. Common marmosets, however, differ from tamarins by actively gouging trees with their anterior teeth to elicit tree exudate flow. During tree gouging, marmosets produce relatively large jaw gapes, but do not necessarily produce relatively large bite forces at the anterior teeth. We compared the fiber architecture of the masseter muscle in tree-gouging Callithrix jacchus (n = 10) to nongouging Saguinus oedipus (n = 8) to determine whether the marmoset masseter facilitates producing these large gapes during tree gouging. We predict that the marmoset masseter has relatively longer fibers and, hence, greater potential muscle excursion (i.e., a greater range of motion through increased muscle stretch). Conversely, because of the expected trade-off between excursion and force production in muscle architecture, we predict that the cotton-top tamarin masseter has more pinnate fibers and increased physiological cross-sectional area (PCSA) as compared to common marmosets. Likewise, the S. oedipus masseter is predicted to have a greater proportion of tendon relative to muscle fiber as compared to the common marmoset masseter. Common marmosets have absolutely and relatively longer masseter fibers than cotton-top tamarins. Given that fiber length is directly proportional to muscle excursion and by extension contraction velocity, this result suggests that marmosets have masseters designed for relatively greater stretching and, hence, larger gapes. Conversely, the cotton-top tamarin masseter has a greater angle of pinnation (but not significantly so), larger PCSA, and higher proportion of tendon. The significantly larger PCSA in the tamarin masseter suggests that their masseter has relatively greater force production capabilities as compared to marmosets. Collectively, these results suggest that the fiber architecture of the common marmoset masseter is part of a suite of features of the masticatory apparatus that facilitates the production of relatively large gapes during tree gouging.

Animals↗

PubMed1996

Homologies between human and marmoset (Callithrix jacchus) chromosomes revealed by comparative chromosome painting.

Regions of DNA homology between human and marmoset (Callithrix jacchus) chromosomes have been demonstrated using fluorescence in situ hybridization. All 24 chromosome paints and two centromere repeat sequences from Homo sapiens (HSA) have been annealed to previously G-banded metaphase spreads of Callithrix jacchus. All human paint probes, except Y, successfully hybridized to marmoset chromosomes. Fifteen of them hybridized to one region only, seven to two regions, and paint 1 to three regions. Homologies proposed from previous banding comparisons have been confirmed for HSA 2, 4-6, 10-12, 18, 19, 21 and X and partially confirmed for HSA 1 and 3, but were not in agreement for HSA 14 and 17. Human centromere repeat sequences for X and 18 did not hybridize to marmoset chromosomes. Because, at present, there is the confusion situation of several different numbering systems for marmoset chromosomes, we propose a new simpler nomenclature based on descending order of chromosome size.

Animals↗

PubMed1992

Karyotypic comparison among Cebuella pygmaea, Callithrix jacchus and C. emiliae (Callitrichidae, Primates) and its taxonomic implications.

The karyotype of Cebuella pygmaea (2n = 44) obtained by G-, C-banding, and NOR-staining is described. This species presents a heteromorphic C band in the intersticial region of the short arm of chromosome 2. The data obtained were compared with those previously described for the karyotypes of Callithrix jacchus and Callithrix emiliae. The three species differ in the amount and distribution of non-centromeric constitutive heterochromatin. The importance of the variation in constitutive heterochromatin for the phylogeny of the group is discussed. Comparison of the karyotypes in terms of G-banding patterns showed that C. pygmaea and C. emiliae differ from C. jacchus by a Robertsonian translocation and a paracentric inversion, whereas C. pygmaea and C. emiliae differ from each other by a reciprocal translocation between an acrocentric autosome and the short arm of the submetacentric chromosomes that distinguishes their karyotypes from that of C. jacchus. The possible evolutionary paths followed by the karyotypes of the three species are discussed.

Animals↗

PubMed1990

Chromosomal evolution in Callithrix emiliae.

We studied the karyotype of specimens of Callithrix emiliae (Callithricidae, Primates) from Rondonia, Brazil. Comparison with the karyotype of Callithrix jacchus showed that, even though these two species show many karyotypic similarities, they differ by a Robertsonian translocation, a paracentric inversion and large-scale addition of heterochromatin. The C. emiliae species appears to be in an active phase of chromosome evolution by the addition of constitutive heterochromatin.

Animals↗

PubMed1999

Normal development of refractive state and ocular component dimensions in the marmoset (Callithrix jacchus).

Refractive state and ocular dimensions were studied longitudinally in nine normal marmosets. Animals were anaesthetised and examined (with some exceptions) at 4, 6, 7, 8, 10, 15, 24 and 39 weeks of age. Cycloplegic retinoscopy showed that hyperopia early in life rapidly diminished. Refraction corrected for the artefact of retinoscopy stabilised by 8 weeks of age, but at a slightly myopic value, rather than at emmetropia. The ocular components continued to change throughout the period studied. Corneal radius, measured by photokeratometry, increased slightly during development. Anterior segment depth and vitreous chamber depth (VCD), measured by A-scan ultrasonography, increased throughout development while lens thickness initially increased and then decreased. Data from the eyes of these normal animals were compared with that from the contralateral eyes of animals which received short periods of monocular deprivation early in life (Troilo, D., & Judge S.J. (1993). Ocular development and visual deprivation myopia in the common marmoset (Callithrix jacchus jacchus). Vision Research, 33, 1311-24); eyes which viewed through no lens or a plano lens (Graham, B. & Judge, S.J. (1999)). The effects of spectacle wear in infancy on eye growth and refractive error in the marmoset (Callithrix jacchus). Vision Research, 39, 189-206), and eyes of normal animals in another colony. There were no significant differences between the first two groups and the normal animals in our colony while age-matched animals from the other colony were slightly but significantly less myopic than our animals.

Animals↗

PubMed2001

Expression of the estradiol-synthesizing 17beta-hydroxysteroid dehydrogenases type 1 and type 7 in the nonhuman primate Callithrix jacchus.

The common marmoset monkey (Callithrix jacchus) was used as a primate model for the study of the expression of the estradiol synthesizing enzymes 17beta-hydroxysteroid dehydrogenase type 1 and type 7 (17HSD1 and 17HSD7). The tissue-specific expression of 17HSD1 and 17HSD7 mRNA in Callithrix jacchus and human as shown by Northern Blot analysis revealed strong similarities between the two species. After cloning of the marmoset-specific coding cDNA sequence of 17HSD7 a similarity of 95% to the known human sequences was found. To elucidate the physiological function of 17HSD7 which is thought to be different to that of the well-known 17HSD1, the regulation of 17HSD7 expression in the corpus luteum was investigated. It was shown to be upregulated during the luteal phase of the reproductive cycle and during early pregnancy, when the primate corpus luteum is most active in estradiol synthesis, whereas 17HSD1 was not detectable in this tissue at any time.

17-Hydroxysteroid Dehydrogenases↗

PubMedDate not supplied

Ocular dominance columns in the adult New World Monkey Callithrix jacchus.

In the marmoset Callithrix jacchus, ocular dominance columns (ODC) have been reported to be present in young animals, but absent in adults (Spatz, 1989). We have studied in juvenile and adult animals the postnatal organization of the retino-geniculo-cortical afferents by means of transneuronal labeling. We show in the present work that ODC are present in the primary visual cortex of Callithrix jacchus, both in the adult and in the juvenile animal. The present work confirms the presence of ODC in the visual cortex of juvenile marmoset before the end of the first postnatal month. In 2-month-old animals, ODC are well demarcated in IVcalpha and IVcbeta. In the adult marmosets, the present data clearly show that the primary visual cortex is also organized with ODC. In horizontal sections, they form a mosaic through the ventral and dorsal calcarine cortex and through the dorso-lateral occipital part of the striate cortex. In frontal sections, their presence is manifest in IVcbeta within the calcarine cortex and they only faintly appear in IVcalpha. These new findings are important since they underline the usefulness of the adult New World Monkeys as a model in visual research.

Aging↗

PubMed2005

The seminiferous epithelium cycle length in the black tufted-ear marmoset (Callithrix penicillata) is similar to humans.

Marmosets are New World small primates phylogenetically close to humans and are commonly used in biomedical research. Although the reproductive biology of the common marmoset Callithrix jacchus is fairly well investigated, there are few data available for testis function for its close relative, Callithrix penicillata. In this regard, the present study was performed to investigate testis structure, spermatogenic cycle length, and spermatogenic and Sertoli cell efficiencies in eight captive C. penicillata. These animals received (3)H-thymidine injections and had their testes perfused-fixed with glutaraldehyde and embedded in plastic at different time periods after (3)H-thymidine injections, for histomorphometric and autoradiographic evaluation. The analysis of the different germ cell associations showed that two or more stages were observed in about 30% of the seminiferous tubule cross sections investigated. The values found for spermatogenic cycle length and for total duration of spermatogenesis in the marmoset C. penicillata, 15.4 and 69.3 days respectively, were very close to those cited in the literature for humans. However, the results observed for Sertoli cell efficiency (number of round spermatids per Sertoli cell; 8:1) and spermatogenic efficiency (daily sperm production per gram of testis; 18.4 million) were substantially higher than those observed for humans. The results found in the present investigation suggest that the black tufted-ear marmoset C. penicillata might represent an alternative and useful experimental model to perform comparative studies regarding the spermatogenic process, particularly in investigations related to the expansion of spermatogonial stem cells and the establishment of spermatogenic waves.

Animals↗

PubMed2005

Investigation of marmoset hybrids (Cebuella pygmaea x Callithrix jacchus) and related Callitrichinae (Platyrrhini) by cross-species chromosome painting and comparative genomic hybridization.

We report on the cytogenetics of twin offspring from an interspecies cross in marmosets (Callitrichinae, Platyrrhini), resulting from a pairing between a female Common marmoset (Callithrix jacchus, 2n = 46) and a male Pygmy marmoset (Cebuella pygmaea, 2n = 44). We analyzed their karyotypes by multi-directional chromosome painting employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. Both hybrid individuals had a karyotype with a diploid chromosome number of 2n = 45. As a complementary tool, interspecies comparative genomic hybridization (iCGH) was performed in order to screen for genomic imbalances between the hybrids and their parental species, and between Callithrix argentata and S. oedipus, respectively. These genomic imbalances were confined to centromeric and telomeric heterochromatin, while euchromatic chromosome regions appeared balanced in all species investigated. When comparing marmosets and tamarins, sequence divergence of centromeric heterochromatin was already clearly noticeable. In the C. argentata and C. pygmaea genomes numerous subtelomeric regions were affected by amplification of different repetitive sequences. Cross-species FISH with a microdissection-derived C. pygmaea repetitive probe revealed species specificity of this repetitive sequence at the molecular cytogenetic level of resolution.

Animals↗

PubMedDate not supplied

Colour discrimination in the black-tufted-ear marmoset (Callithrix penicillata): ecological implications.

The dietary diversity of marmosets is substantial, which may reflect differences in their colour vision. This study examined the colour discrimination ability of a gummivore/insectivore callitrichid, Callithrix penicillata, which inhabits the Brazilian cerrado (bush savanna). A series of ecologically relevant tasks, involving a behavioural paradigm of discrimination learning in semi-natural conditions and the usage of ecologically relevant stimuli, was executed. Three marmosets, 2 males and a female, behaved like human dichromats, showing an impaired performance when orange and green stimuli had to be discriminated. In contrast, 2 females resembled human trichromats, discriminating those kinds of pairs. Our data suggest that Callithrix penicillata presents a polymorphic trichromacy, with dichromatic males and dichromatic or trichromatic females.

Animals↗

PubMed1993

Social organization in a wild population of Callithrix jacchus. I. Group composition and dynamics.

Data are presented on group dynamics in a wild population of the common marmoset, Callithrix jacchus, in northeastern Brazil. Three marked and habituated groups were observed, and composition noted, for at least 5 days a month over 12-18 consecutive months. Group sizes ranged from 5 to 15 individuals, and changes in group composition were the result of births, immigrations, and disappearances. No immigrations into the main study groups were observed throughout the study period. None of the three known emigrants was known to join an established or incipient group for up to 10 weeks after their departure. One group contained only breeding individuals and their offspring. Observations of recruitment and loss in the other two groups suggest that they, too, were extended family groups. The group dynamics described in studies of other populations of Callithrix suggest that extended family groups, or at least groups consisting of breeding individuals and their close relatives, may be characteristic of those populations.

Animals↗

PubMed1992

Influence of dexamethasone on the RM 3/1-positive macrophages in the peripheral blood and tissues of a New World monkey (the marmoset Callithrix jacchus).

Subcutaneous injection of the glucocorticoid dexamethasone in the primate Callithrix jacchus increased the proportion of the macrophage subtype RM 3/1 in the blood from a basic level of 16% positive monocytes to about 65%. The elevated numbers of RM 3/1-positive cells were seen 24 and 72 h after application and were independent of the dosages used (50 or 150 micrograms/kg). Oral administration had no effect. CD4-, CD14- and CDw14-antigen expression of monocytes was not influenced by the dexamethasone treatment. In tissues, e.g. spleen, thymus, liver, skin and kidney, RM 3/1-positive macrophages revealed a similar distribution as in human tissues but no differences in glucocorticoid treated to control animals could be observed. These results show that glucocorticoids induce in the monkey Callithrix jacchus a distinct monocyte subtype similarly as in man while other macrophage phenotypes were not influenced.

Animals↗

PubMed1994

Evaluation of possible effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and other congeners on lymphocyte receptors in Callithrix jacchus and man.

Using fluorescence-labeled monoclonal antibodies and flow cytometry (FACScan analysis) we measured surface receptors on peripheral lymphocytes in marmosets (Callithrix jacchus) treated with TCDD in the lower nanogram per kilogram range. Additionally, some polybrominated congeners were studied as well as a 2,3,7,8-substituted dioxin containing chlorine and bromine in the same molecule. Callithrix was found to be very sensitive to the action of TCDD and the other tetrahalogenated congeners; single doses of 10-30 ng/kg body weight reproducibly induced a decrease in the percentage and absolute number of 'memory' helper T cells [CD4+CD29(bright)] and of B cells (CD20+). Subsequently, according to the hypothesis based on the marmoset data, extensive analyses on surface receptors of white blood cells were performed in workers with moderately increased body burdens of TCDD, and for further hypothesis generation > 60 triple-labeling assays were performed with each of the blood samples. No decrease in typical surface receptors (CD4+CD45R0+CD45RA-CD29(bright) or CD20+) was found in the human adult volunteers studied, but a trend toward an increase was noted. It cannot be decided whether this may be a substance-related effect, or results from a confounder (possibly age differences between the groups).

Adult↗

PubMed2004

[Alterations in cholesterol, triglyceride and total phospholipid levels in plasma of Callithrix jacchus (sagüi) reinfected by Schistosoma mansoni].

Little information is available on the lipid changes caused by Schistosoma mansoni reinfection. In this work it was evaluated alteration in the plasma lipids due to one reinfection by Schistosoma mansoni in the non human primate Callithrix jacchus (sagüi). Blood samples from C. jacchus, prior and after 60 days infection and reinfection, were collected by intravenous puncture, anticoagulated with EDTA (1mg/mL) and centrifuged at 2,500 xg, in order to obtain the plasma. Total cholesterol, cholesteryl ester, total phospholipid and triglyceride levels were determined by spectrophotometer methods. The results showed that there are significant reduction in cholesterol total, cholesteryl ester, total phospholipid and triglyceride concentrations in plasma of animals reinfected by Schistosoma mansoni, in comparison to the same animals prior and after one infection. This study showed that a second infection of Callithrix jacchus by Schistosoma mansoni causes plasma lipid alterations, which are more significant than after a single infection.

Animals↗