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PubMedDate not supplied

Experimental schistosomiasis in the common marmoset Callithrix jacchus.

In order to evaluate Callithrix jacchus as an animal model for mansoni schistosomiasis, a group of 10 male animals were once percutaneously exposed to 250 cercariae of the Schistosoma mansoni SLM (São Lourenço da Mata) strain. Animals were periodically bled for measuring serum level of enzymes and proteins and for blood cell counting. When comparing pre-infection to post-infection values, a significant increase was found for alkaline phosphatase at 15 to 120 days p.i., differential counts of eosinophil at 45 and 60 days, and total protein and global eosinophil counts at 120 days. No Schistosoma mansoni eggs were found in stools. Adult worms of small size were recovered from five animals. At day 120, the number of Schistosoma mansoni eggs/g of tissue was 0-289.7 (liver), 0-30.1 (large intestine) and 0-171.4 (small intestine). These findings lead us to classify Callithrix jacchus as a non-permissive host to the SLM strain of Schistosoma mansoni.

Animals↗

PubMedDate not supplied

Experimental infection with Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis in the marmoset, Callithrix penicillata (Primates:Callithricidae).

Fourteen marmosets (Callithrix penicillata) were inoculated intradermally with promastigotes and/or amastigotes of Leishmania (Viannia) braziliensis (L. (V) b.) strains MHOM/BR/83/LTB-300 MHOM/BR/85/LTB-12 MHOM/BR/81/LTB-179 and MHOM/BR/82/LTB-250. The evolution of subsequent lesions was studied for 15 to 75 weeks post-inoculation (PI). All but 3 of the L. (V) b. injected marmosets developed a cutaneous lesion at the point of inoculation after 3 to 9 weeks, characterized by the appearance of subcutaneous nodules containing parasites. Parasites were isolated by culture (Difco Blood Agar) from all 11 positive animals. The maximum size of the lesions was variable and ranged between 37 mm2 to 107 mm2. Ulceration of primary nodules became evident after 3 to 12 weeks in all infected marmosets, but was faster and larger in 5 of the 11 animals. The active lesions persisted in 9 out of 11 Callithrix until the end of the observation period, which varied from 15-75 weeks. In 3 animals spontaneous healing of their lesions (13 to 25 weeks, PI) was observed but with cryptic parasitism. In another 2 infected animals there was regression followed by reactivation of the cutaneous lesions. The appearance of smaller satellite lesions adjacent to primary ones, as well as metastatic lesions to the ear lobes, were documented in 2 animals. Promastigotes of L. (Leishmania) amazonensis (L. (L) a.) MHOM/BR/77/LTB-16 were inoculated in 1 marmoset. This animal remained chronically infected for 6 months and the lesion developed in a similar manner to L. (V) b. infected marmosets. No significant differences in clinical and parasitological behaviour were observed between promastigote or amastigote derived infections of the 2 species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

The mossy fiber terminals in the hippocampal formation of Callithrix jacchus: comparative and evolutionary considerations.

The distribution of mossy fiber terminals in the regio inferior of the hippocampus of Callithrix jacchus was studied by means of Timm's method. The topographic distribution of Timm-positive zones in the hilus, in the suprapyramidal and intrapyramidal areas of the CA3 subfield is described. A Timm-positive reaction in intragranular strips and supragranular zones, the presence of Timm-negative zones in the infragranular border of the fascia dentata were found in this species. A comparison between mossy fiber distribution in Callithrix jacchus and that in human was carried out in an attempt to identify interspecies differences in the mossy fiber system in the hippocampus of primates. The hypothesis of a possible functional relevance of the supra- and intrapyramidal mossy fiber terminals on the control of hippocampal pyramidal neurons is expressed.

Animals↗

PubMed1993

Alteration of circadian period length does not influence the ovarian cycle length in common marmosets, Callithrix j. jacchus (primates).

To investigate the coupling between the circadian system and the regulation of the ovarian cycle in nonhuman primates, the effect of Zeitgeber-induced alterations of the circadian period (23 vs 26 h) on the ovarian cycle length was studied in the long-cycling polyestrous common marmoset, Callithrix j. jacchus. For that purpose, six female marmosets were isolated for approximately 4 months each under artificial lighting regimens of 23 h [light-dark (LD) 11.5:11.5] and of 26 h (LD 13:13; 300:0.03 lx). Samples of "morning urine" were collected in each circadian period and analyzed by radioimmunoassay for their estrone (E1) and estradiol-17 beta (E2) concentrations. Clear ovarian cyclic variations of the creatinine related urinary E1 and E2 concentrations were ascertained in each individual, with the E2 concentrations being 5-10 times higher than the E1 concentrations. In a total of 48 recorded ovarian cycles, the cycle length varied between 16 and 39 days and was 28.3 +/- 4.1 days on average. As measured in circadian periods, the marmosets' ovarian cycle was significantly longer (p < 0.05) under entrainment to LD 11.5:11.5 than under entrainment to LD 13:13. When measured in objective days, however, no difference in cycle length was demonstrated. Hence, in Callithrix, the mechanisms regulating the ovarian cycle length do not seem to be closely coupled to the circadian system, but rather corroborate the more classic hypothesis presuming that in polyestrous mammals different (at most weakly coupled) timing mechanisms or oscillator systems are responsible for the regulation of the circadian and the ovarian cycles.

Animals↗

PubMed2000

Characterization of constitutive heterochromatin of Callithrix geoffroyi (Callitrichidae, Primates) by restriction enzymes and fluorochrome bands.

The neotropical primate genus Callithrix comprises two groups of species, jacchus and argentata, which inhabit distinct geographical regions and manifest different fur coloration and constitutive heterochromatin (CH) markers in their karyotypes. In this investigation the CH of a representative of the jacchus group, Callithrix geoffroyi, was analysed using fluorochromes and restriction enzymes in situ. To clarify the source of the constitutive heterochromatin of both groups, the data obtained in the jacchus group were compared with those published in the argentata group obtained by the same techniques. The C-bands of C. geoffroyi (four specimens, 2n = 46) were centromeric in all chromosomes, and distally located in pairs 6 and 22. The Alu I, Hae III, Hin fI, Rsa I, Dde I, Mbo I, and Msp I restriction endonucleases and CMA3 and DAPI fluorochromes produced different bands, which allowed the characterization of four distinct types of constitutive heterochromatin in the C. geoffroyi genome. Several of these types of heterochromatin were present in the ancestor of the two groups of species, jacchus and argentata, while others originated after their cladogenesis.

Animals↗

PubMed1981

Competition for a desired food in family groups of the common marmoset (Callithrix jacchus) and the cotton-top tamarin (Saguinus oedipus).

Four captive groups of common marmosets (Callithrix jacchus) and three groups of cotton-top tamarins (Saguinus oedipus) were each presented with a desired food and their consumption was monitored. Inequalities in consumption between individuals were found for each group of each species. Generally, adult females consumed most of the desired food, followed by juveniles, and finally adult males. High consumption levels by all individuals during isolated feedings indicated that consumption inequalities within groups were most likely due to competition rather than inter-individual preference differences. Aggressive defense of the food cup was performed most frequently by adult females in both species. In Callithrix jacchus groups, this aggression was most often directed against adult males, but in Saguinus oedipus groups, it was most often directed against juveniles. Modification of the method of food presentation, such that food was more dispersed, lessened, but did not eliminate, inequalities in consumption.

Aggression↗

PubMed1993

Arthritis of the spondyloarthropathy variety in Callithrix jacchus.

Sixty skeletons of Callithrix jacchus were examined to identify spondyloarthropathy. Erosive disease in Callithrix was confirmed as spondyloarthropathy on the basis of diagnostic sacroiliac erosions, syndesmophyte formation, and the nature and distribution of the peripheral joint erosions.

Animals↗

PubMed1995

The weight of the heart in Callithrix Erxleben, 1777.

The allometric relationship between the weight of the heart and the body measurements was analyzed in 31 primates of genus Callithrix (C. jacchus and C. penicillata). The data were analyzed after logarithmic transformation using the model: Ln Y = Ln a + (b) Ln X. We compared with the t-test the slopes of the males and females and the slopes of the C. Jacchus and C. penicillata. Positive allometry was found to the weight of the heart in relation to the body weight (except to females of C. penicillata = isometry) and to sitting height in females of C. jacchus and males of C. penicillata. The relationship of the weight of the heart with the sitting height was isometric in males of C. jacchus and negative in females of C. penicillata. We cannot reject the null hypothesis analyzing the differences between the slopes of males and females. Therefore, in these two species of Callithrix we accept the concept of monomorphism.

Animals↗

PubMed1995

Behavior and progesterone levels in Callithrix jacchus females.

In callitrichids, and especially in the Callithrix and Saguinus genera, reproductive suppression maintains the breeding exclusivity of dominant females. It has been suggested that dominance may be inferred from agonistic behavior of females. The purpose of this study was to assess the adequacy of behaviors as indicators of hormonal status in Callithrix jacchus females. Two pairs of twin females were observed for affiliative, agonistic and sexual behaviors for 20 weeks, in four stages of increasingly potential competition for one male. During the same period, blood samples were taken regularly for progesterone determination by ELISA. The two pairs differed markedly as to behaviors and hormonal status: pair 1 showed a well established behavioral dominance and only one ovulating female from the beginning of the observation period; pair 2 showed competition for dominance until the last stage of observation, when one of the females started ovulating. Correlations between behaviors and progesterone levels showed differences between subordinate and dominant females mostly in pair 2. Although limited in number of animals studied, these results suggest that there is a relationship between behavior and hormones in female marmosets, but this relationship may be useful in the identification of the physiological status of females only in groups where the dominance is not well established.

Agonistic Behavior↗

PubMed1978

The retino-geniculo-cortical pathway in Callithrix. I. Intraspecific variations in the lamination pattern of the lateral geniculate nucleus.

Injections of tritiated tracer precursors into one eye revealed a highly variable lamination pattern of the LGN in the marmoset Callithrix. In one specimen, only four cell layers were apparent with some indication of further differentiation. In a second specimen, six almost complete relay layers were found in the occipital portion of the LGN. Three other animals showed stages between these two extremes. The lamination pattern of Callithrix thun represents an intermediate stage between a four-layered LGN suggested as the basic primate pattern, and the advanced six-layered LGN of most other anthropoid monkeys. In addition, bilateral retinal terminations were found consistently in layer 0, and contralateral terminations in a narrow band between the magnocellular and parvocellular portions of the nucleus, and within the interlaminar zone which separates the two magnocellular layers.

Animals↗

PubMed2000

Home range of a Geoffroy's marmoset group, Callithrix geoffroyi (Primates, Callitrichidae) in South-eastern Brazil.

The home range of one group of the Geoffroy's marmoset (Callithrix geoffroyi) was studied in a fragment of the Atlantic Forest in south-eastern Brazil, between February 1993 and January 1994. The total home range was 23.3 ha and the area used in the dry season was significantly larger than that of the wet season. The smallest distance travelled by group was 480 m/day in May and the longest was 1,980 m/day in March, but with no significant differences between seasons. The total home range used for this species agrees with the ecological grouping of the genus Callithrix proposed by Rylands & Faria (1993) and may be associated with the habitat structure, the limit of the fragment and the inexistence of neighbouring groups.

Journal Article↗

PubMed1978

[Transferrin findings in Callithrix jacchus Linné, 1758 (Primates, Platyrrhina)].

This paper deals with the transferrin (Tf) polymorphism in the South American marmoset Callithrix jacchus. The transferrin bands of this species are positioned in the electropherogramme cathodal to the beta1C-globulin (C 3), s. Fig. 1. By means of the combined agarose gel immuno-electrophoresis 7 distinguishable phenotypes have been detected in 166 animals (s. Fig. 2). The formal genetic analysis of 28 matings with 48 youngs (cf. Table 1) leads to the assumption that at least 4 codominant alleles (Tf Cja, Tf Cjb, Tf Cjc, Tf Cjd) are existent at the autosomal Tf-locus in Callithrix jacchus.

Alleles↗

PubMed1975

[Observations, analyses and experiments on the use of the hand in Callithrix jacchus Erxleben, 1777. Part II. Fine analysis of prehensive behavior].

The use of the hand of the common marmoset (Callithrix jacchus Erxleben, 1777) was analysed on the basis of observations and experiments conducted on 56 animals of all age. During arboreal locomotion Callithrix jacchus makes use of the hands for support and for grasping to maintain its balance, The palmar region serves as the main means of support, while the findgers in the locomotor grip also contribute to maintaining balance and support. The greater the need for maintaining balance, for example, during vertikal climbing or in movement along the narow branches, the mre complete the djustment of the hand form on the surface and the more complete the alignment of the hand on the branch will be. Additional support is supplied by the longitudinal palm furrow, caused by the radio-ulnar adduction of the hand edges and by the clinging properties of the volar pads...

Age Factors↗

PubMed1996

Comparison of photoreceptor spatial density and ganglion cell morphology in the retina of human, macaque monkey, cat, and the marmoset Callithrix jacchus.

We studied the relationship between the morphology of ganglion cells and the spatial density of photoreceptors in the retina of two Old World primates, human and macaque monkey; the diurnal New World marmoset Callithrix jacchus; and the cat. Ganglion cells in macaque and marmoset were labelled by intracellular injection with Neurobiotin or by DiI diffusion labelling in fixed tissue. Cone photoreceptor densities were measured from the same retinas. Supplemental data for macaque and data for human and cat were taken from published studies. For the primates studied, the central retina is characterised by a constant numerical convergence of cones to ganglion cells. Midget ganglion cells derive their input, via a midget bipolar cell, from a single cone. Parasol cells derive their input from 40-140 cones. Outside the central retina, the convergence increases with eccentricity. The convergence to beta cells in the cat retina is very close to that for parasol cells in primate retina. The convergence of rod photoreceptors to ganglion cells is similar in human, macaque, and marmoset, with parasol cells receiving input from 10-15 times more rods than midget cells. The low convergence of cones to midget cells in human and macaque retinas is associated with distinctive dendritic "clusters" in midget cells' dendritic fields. Convergence in marmoset is higher, and the clusters are absent. We conclude that the complementary changes in photoreceptor density and ganglion cell morphology should be considered when forming linking hypotheses between dendritic field, receptive field, and psychophysical properties of primate vision.

Animals↗

PubMed1996

Morphology of retinal ganglion cells in a new world monkey, the marmoset Callithrix jacchus.

We studied the morphology of retinal ganglion cells in a diurnal New World primate, the marmoset Callithrix jacchus. This species is of interest as a model for primate vision because it has good behavioural visual acuity, and the retina and subcortical visual pathways are very similar to those of Old World monkeys and humans. Ganglion cells were labelled by placing small crystals of the carbocyanin dye DiI into the optic fibre layer, or by intracellular injection of neurobiotin. Two main classes of ganglion cell were labelled. We call these Group A cells and Group B cells: they are respectively homologous to parasol and midget cell classes. Group A and Group B cells show similar patterns of dye coupling, dendritic stratification and dendritic field size as their counterparts in Old World monkeys and humans. A third group of cells, which we call Group C, is morphologically heterogeneous. Examples corresponding to wide-field ganglion cell types described in Old World primates were encountered. One subgroup of C cells has a morphology very similar to that of the small bistratified (blue-on) cell described in macaque retina, suggesting that this functional pathway is common to all primates. As for other New World monkeys, the marmoset shows a sex-linked polymorphism of cone pigment expression, such that all males are dichromats and the majority of females are trichromats. No systematic differences in Group B cells were seen between male and female retinas, suggesting that trichromacy is not accompanied by specific changes in ganglion cell morphology.

Animals↗

PubMed1997

N-methyl-D-aspartate subunit R1 involvement in the postnatal organization of the primary visual cortex of Callithrix jacchus.

It has been demonstrated that the primary visual cortex is highly sensitive to manipulations of the visual environment during a specific, early, postdevelopmental period: the critical period. Pharmacological studies have shown that N-methyl-D-aspartate (NMDA) receptors are involved in the plasticity of the visual cortex just as they are involved in the induction of long-term potentiation (LTP), another activity-dependent form of plasticity. The setting up of synaptic connectivity in the neocortex may rely on LTP-like mechanisms. By using immunohistochemistry techniques, we tested the hypothesis of the role of subunit R1 of NMDA (NMDAR1) receptors in the thalamocortical afferent segregation into ocular-dominance columns in the New World monkey, Callithrix jacchus. We employed early and short (2 weeks) monocular-deprivation periods at different ages of postnatal development (17, 46, 67, 107, and 188 postnatal days). We observed heterogeneous distribution of NMDAR1 in the layer IVC receiving the thalamic inputs if the deprivation was realized between the ages of 46 and 107 days. Layers IVCalpha and IVCbeta were involved differently as a function of the deprivation age. The striped pattern lost its differential intensity with the postnatal age. These results are compared with the ocular-dominance pattern evolution described in other works on this primate. They provide evidence of the NMDAR1 role in the modular organization, within time limits, during the postnatal development of the primary visual cortex.

Aging↗

PubMed1999

Synaptic input to small bistratified (blue-ON) ganglion cells in the retina of a new world monkey, the marmoset Callithrix jacchus.

Small bistratified (blue-ON) ganglion cells in the primate retina are involved in processing short wavelength sensitive cone signals. These ganglion cells stratify in both the ON- and OFF-sublamina of the inner plexiform layer. We investigated the origin of synaptic input to the small bistratified ganglion cell in the retina of a New World primate, the marmoset Callithrix jacchus. Two small bistratified cells from peripheral retina were intracellularly filled with Lucifer Yellow, subsequently photoconverted and processed for electron microscopy. Serial ultrathin sections were cut through portions of each cell, and these were analysed in the electron microscope. The majority of synaptic input (about 84%) to both the inner and outer tier of dendrites was from amacrine cells. Both dendritic tiers also received bipolar cell input. These findings are consistent with predictions from physiological studies that synaptic input to the inner and outer tier of small bistratified cells should be excitatory. However, the tiny fraction of total input supplied from bipolar cells to the outer tier is not consistent with the strong excitatory OFF response in cells of this pathway.

Animals↗

PubMed1997

Cardiac-like musculature of the intrapulmonary venous wall of the long-clawed shrew (Sorex unguiculatus), common tree shrew (Tupaia glis) and common marmoset (Callithrix jacchus).

BACKGROUND: The cardiac-like musculature is distributed not only in the heart wall but also in the intrapulmonary venous wall in a few species of insectivores. It has been suggested that the evolutionary origin of venous cardiac-like musculature may be traceable to a basic stock of certain mammalian lines of descent. So, it is important to clarify whether the musculature may be a common structure in lower mammals from insectivores to primates and to examine the functional significance of the structure. METHODS: The distribution of cardiac-like musculature in the intrapulmonary venous wall of the long-clawed shrew (Sorex unguiculatus), common tree shrew (Tupaia glis), and common marmoset (Callithrix jacchus) was observed by light and electron microscopy. The presence of atrial natriuretic polypeptide (ANP) was examined in the musculature by immunohistochemistry. RESULTS: All three species contained cardiac-like myocytes in the tunica media of intrapulmonary venous wall. In the common tree shrew and the common marmoset, cardiac-like musculature was found in the small intrapulmonary vein of 150-200 microns in diameter, while, in the long-clawed shrew, it was distributed even in the intrapulmonary vein of 30 microns in diameter. Ultrastructure of myocytes was fundamentally similar to that of atrial myocytes in the long-clawed shrew and the common tree shrew. The presence of atrial natriuretic polypeptide (ANP) was also demonstrated by immunohistochemistry in the intrapulmonary venous walls of common tree shrews. CONCLUSIONS: The results indicate that the pulmonary venous cardiac-like musculature occurs in the lower eutherian mammals from insectivores to primitive primates. The musculature is thought to act as a regulatory pump in pulmonary circulation and as an endocrine apparatus of ANP.

Animals↗