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An assessment of the fertilizing ability of spermatozoa in the epididymis of the marmoset monkey (Callithrix jacchus).

The fertilizing ability of spermatozoa from differ regions of the epididymis of the marmoset monkey, Callithrix jacchus, was assessed by determining their rate of fusion with zonaless hamster ova in vitro. This technique tests for functional competence and was validated using epididymal spermatozoa of the hamster whose fertility have been measured previously by in vivo fertilization experiments. The results suggest that some marmoset spermatozoa first acquire the ability to fertilize in the distal caput and proximal corpus epididymidis although the majority become fertile on reaching the proximal cauda region. Acquisition of fertilizing capacity was associated with a change in the degree and character of sperm motility. However, it is considered that modifications to the sperm plasmalemma which allow capacitation and the acrosome reaction to occur are of primary importance for sperm fertility. The development of sperm fertilizing ability in the marmoset is discussed in relation to that in other primates.

Animals↗

Reproductive efficiency in the common marmoset (Callithrix jacchus): a longitudinal study from ovulation to birth monitored by ultrasonography.

This study examines reproductive efficiency in the common marmoset monkey, Callithrix jacchus, using sequential ultrasound examinations to establish ovulation number, implantation rate, and incidence of prenatal loss. Ultrasound was carried out with a 10 or 7.5 mHz probe in nonsedated animals, daily during the late follicular phase, approximately twice a week until day 20 after ovulation, and at days 35, 56, and 85 of pregnancy to enable visualization of gestation sacs, heartbeats, and fetal heads, respectively. Ovulatory follicles could be seen 3-4 days before ovulation and by day -2, 98% of ovulating follicles were > 2mm diameter, although almost 10% of follicles of this size disappeared without ovulating. Total number of ovulating follicles for 15 females was 45 (mean ovulation rate = 3.0, range 2-4). In the 14 animals that conceived, 41 corpora lutea were identified (mean ovulation rate = 2.9) within 10 days of ovulation. All pregnancies went to term (no abortion occurred) resulting in the birth of 37 neonates (9 triplets, 5 twins) and an average litter size of 2.64. All four losses were confined to the embryonic period (< day 85), two occurring before day 35, one between days 35 and 56, and one between days 56 and 85. In demonstrating that 90% of ovulatory follicles gave rise to live offspring, the results of this study indicate an extremely high reproductive efficiency in the marmoset monkey (when maintained under favorable captive conditions) and a rate of prenatal loss much lower than that reported for other primate species.

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Estimation of gestational ages in the common marmoset (Callithrix jacchus) from published prenatal growth curves.

This report compares estimated gestational ages from published cubic spline curves to gestational ages estimated retrospectively from delivery dates in 28 pregnancies from ten common marmosets (Callithrix jacchus). Both CRL- and BPD-based estimates of gestational age were closely correlated with delivery-based gestational age estimates. Of the three ultrasound machines used, the one with 16 shades of gray and a sequential linear array overestimated gestational age during early pregnancy, based on CRL measures. Measures from the other two machines (64 or 264 shades of gray; linear sector and annular array or electronic phase array) were similar and resulted in a correlation of the two estimates of gestational age of 0.94 and a mean difference between the two estimates of 0.16 days with 80% of CRL-based gestational age estimates being within +/- 5 days of the delivery-based estimate. The reliability of BPD-based estimates of gestational age was strongly related to pregnancy outcome. BPD-based estimates underestimated gestational age in poor outcome pregnancies (i.e., those in which infants died within 7 days of birth) but not in good outcome pregnancies. The combined CRL- and BPD-based estimates on poor outcome pregnancies suggest that there was less growth in BPD in late gestation for those pregnancies that resulted in nonviable offspring. For good outcome pregnancies, the correlation between BPD-based and delivery-based estimates of gestational age was 0.871 and the mean difference between the two estimates was -0.06 days with 83.3% of BPD-based estimates falling within +/- 5 days of delivery-based estimates.

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Intestinal cryptococcosis in a common marmoset (Callithrix jacchus).

A five-year-old female common marmoset (Callithrix jacchus) died after a one-month clinical course of nonspecific signs. Pathologic findings were acute diffuse fibrinonecrotizing enteritis and granulomatous endolymphangitis of intestinal and mesenteric lymphatic vessels. Both lesions were associated with a marked proliferation of Mayer's mucicarmine-positive, 4 to 15 microm yeasts that were surrounded by a wide clear halo. The infection was probably acquired by oral route. Other findings included moderate multifocal granulomatous and necrotizing hepatitis and mesangial nephropathy. Although the immunological status of this marmoset was unknown, cryptococcosis might induce primary lethal intestinal infections in callitrichids.

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Comparison between sex and age class on some physiological, thermal, and hematological indices of the cerrado's marmoset (Callithrix penicillata).

There are few papers about physiological indices in Callithrix penicillata, an increasing primate model in biomedicine. We investigated levels of plasmatic cortisol, plasmatic glucose, free fatty acids, blood cells, tympanic temperature, rectal temperature in C. penicllata, under a fast restraint. Measures of body and weight were accomplished. Males and females were not different regarding any measurements. Body measurements indicated differences between adults and juveniles. Adults showed higher hematocrit and a tendency for higher free fatty acids than juveniles. Right tympanic temperature was higher in adults than juveniles. This result suggests a higher reaction metabolism in adults than juveniles under a restraint stress. Due to the short-time of collecting the data, plasmatic cortisol did not influence physiological parameters. Therefore, we suggest that present results could be considered referential values of C. penicillata physiology.

Age Factors↗

The ductus venosus and intrahepatic venous system in Callithrix jacchus jacchus and Macaca fascicularis fetuses.

BACKGROUND: The ductus venosus (DV) and the intrahepatic branches of the portal vein are arranged as parallel vessels. Blood shunting through the DV ensures fetal survival during periods of stress. The availability of a suitable animal model with similar structure and function to the human fetus would greatly improve the understanding of DV function. The anatomical and histological structure of the DV has not been thoroughly investigated in non-human primate species. METHODS: Morphological investigations were performed on eight marmoset (Callithrix jacchus jacchus) at 112.5 +/- 5.5 days gestational age (mean +/- SEM) and four near-term (165 days) cynomolgus (Macaca fascicularis) fetuses. RESULTS: The DV drains into the collectus venosus. An asymmetrical muscular lip forms a contractile element of the isthmic portion of the DV. A spherical 'dividing' eminence was found on the dorsal wall of the venous collector just above the outlet of the DV in marmoset fetuses. CONCLUSIONS: Our findings regarding the structure of the DV in cynomolgus and marmoset fetuses were generally in agreement with previous descriptions of the morpho-histological structure of the DV in human fetuses.

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Acoustic analysis of vocal development in a New World primate, the common marmoset (Callithrix jacchus).

In contrast to humans and songbirds, there is limited evidence of vocal learning in nonhuman primates. While previous studies suggested that primate vocalizations exhibit developmental changes, detailed analyses of the extent and time course of such changes across a species' vocal repertoire remain limited. In a highly vocal primate, the common marmoset (Callithrix jacchus), we studied developmental changes in the acoustic structure of species-specific communication sounds produced in a social setting. We performed detailed acoustic analyses of the spectral and temporal characteristics of marmoset vocalizations during development, comparing differences between genders and twin pairs, as well as with vocalizations from adult marmosets residing in the same colony. Our analyses revealed significant changes in spectral and temporal features as well as variability of particular call types over time. Infant and juvenile vocalizations changed progressively toward the vocalizations produced by adult marmosets. Call types observed early in development that were unique to infants disappeared gradually with age, while vocal exchanges with conspecifics emerged. Our observations clearly indicate that marmoset vocalizations undergo both qualitative and quantitative postnatal changes, establishing the basis for further studies to delineate contributions from maturation of the vocal apparatus and behavioral experience.

Acoustics↗

Successful infection of the common marmoset (Callithrix jacchus) with human varicella-zoster virus.

The common marmoset, Callithrix jacchus, can be infected with human varicella-zoster virus (VZV), both wild-type strain KMcC and attenuated vaccine strain Oka/Merck. Infection was accomplished with either whole-cell-associated or cell extract VZV by combined oral-nasal-conjunctival application and was characterized by substantial and persistent anti-VZV antibody responses. The infectivity of VZV for marmosets was destroyed by treatment of inocula with heat or UV light. Diluted inocula with as few as 40 PFU/ml were infectious for marmosets. The lungs were demonstrated to be a major site of viral replication; both the presence of viral antigens and signs of pneumonia were demonstrated in lung tissues. Four serial passages of VZV KMcC were carried out in C. jacchus by a process of in vitro isolation and culturing of VZV from infected lung tissue and reapplication of the cultured isolates to fresh animals. The isolated viruses were identified as VZV both serologically and by restriction endonuclease analyses. The C. jacchus infectivity model should prove useful for determining the efficacy of subunit and live recombinant VZV vaccines as well as for the study of zoster.

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Unusual case of metabolic bone disease in a common marmoset (Callithrix jacchus).

Metabolic bone disease was diagnosed in an 11-month-old female common marmoset (Callithrix jacchus). It was depressed, reluctant to move, and was cachectic and small for its age. Laboratory findings included anaemia, azotaemia and an inverse calcium to phosphorus ratio. The radiological findings showed simultaneous signs of osteomalacia and soft-tissue calcification. There was decreased bone density with lytic areas in the pelvis and femur, and severe bilateral nephrocalcinosis. Postmortem examination revealed marked focal dystrophic calcification of the epi- and myocardium. Calcium and vitamin D3 deficiency (nutritional secondary hyperparathyroidism) was the most likely cause of the osteomalacia.

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Segregation of receptive field properties in the lateral geniculate nucleus of a New-World monkey, the marmoset Callithrix jacchus.

The lateral geniculate nucleus (LGN) in humans and Old-World monkeys is dominated by the representation of the fovea in the parvocellular (PC) layers, and most PC cells in the foveal representation have red-green cone opponent receptive field properties. It is not known whether these features are both unique to trichromatic primates. Here we measured receptive field properties and the visuotopic organization of cells in the LGN of a New-World monkey, the marmoset Callithrix jacchus. The marmoset displays a polymorphism of cone opsins in the medium-long wavelength (ML) range, which allows the LGN of dichromatic ("red-green color blind") and trichromatic individuals to be compared. Furthermore, the koniocellular-interlaminar layers are segregated from the main PC layers in marmoset, allowing the functional role of this subdivision of the LGN to be assessed. We show that the representation of the visual field in the LGN is quantitatively similar in dichromatic and trichromatic marmosets and is similar to that reported for macaque; the vast majority of LGN volume is devoted to the central visual field. ON- and OFF-type responses are partially segregated in the PC layers so that responses are more commonly encountered near the external border of each layer. The red-green (ML) opponent cells in trichromatic animals were all located in the PC layers, and their receptive fields were within 16 degrees of the fovea. The koniocellular zone between the PC and magnocellular layers contained cells that receive excitatory input from short wavelength sensitive cones ("blue- cells") as well as other nonopponent cells. These results suggest that the basic organization of the LGN is common to dichromatic and trichromatic primates and provide further evidence that ML and SWS opponent signals are carried in distinct subdivisions of the retinogeniculocortical pathway.

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The mother's participation in infant carrying in captive groups of Leontopithecus chrysomelas and Callithrix jacchus.

Callithrix and Leontopithecus exhibit ecological differences that have implications for the patterns of infant care. In C. jacchus, which uses a small home range because it depends mainly on plant exudates, infants can forage independently early in their life. L. chrysomelas, which feeds mainly on fruits and insects, needs larger home ranges and, therefore, its infants have a more extensive period of dependence. Three families of C. jacchus and four families of L. chrysomelas were studied in captivity. The animals were observed starting from the birth of the infants up to their 8th week of age. Our results suggest that the pattern of infant transfer in L. chrysomelas did not follow the one reported for L. rosalia in that transfers from the mother occurred much earlier. L. chrysomelas infants were carried for about 15% of total time during the 8th week of life against less than 1% in C. jacchus in the same week. Infant care seems to be more extensive in L. chrysomelas than in C. jacchus, and the period of exclusive mother carrying in L. chrysomelas is shorter than that observed in L. rosalia.

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Prolactin levels of fathers and helpers related to alloparental care in common marmosets, Callithrix jacchus.

Previous studies have suggested that prolactin may play a role in regulating allocare behaviour in cotton-top tamarins, Saguinus oedipus. In this study, we investigate the prolactin profile of 3 groups of captive common marmosets, Callithrix jacchus. Carrying behaviour in this species was observed after parturition. Prolactin assays of blood samples of both fathers and helpers (sub-adult non-fathers) in 3 family groups were taken for 8 weeks before and after birth of the infants. The after-birth condition was divided into 2 groups: carrying and non-carrying animals. The results suggest a relationship between prolactin levels and allocare behaviour, with carrying behaviour being associated with increased prolactin in both fathers and helpers. This suggests that extra prolactin is produced in response to physical contact, and may be associated with carrying behaviour. Also, prolactin production may be related to learning parental skills in Neotropical primates.

Animals↗

Social influence on induced food preference in common marmosets (Callithrix jacchus).

In this paper, we investigate the role of sociality in changing an induced food preference in captive common marmosets (Callithrix jacchus), in the particular case of interactions between animals with contrasting information. After modifying a food preference by making a preferred food unpalatable for pairs of individuals (labelled as conditioned individuals) we recorded food choice under three experimental conditions: pairs interacting (one conditioned pair with one non-conditioned pair); pairs separated (conditioned and non-conditioned pairs by themselves the day after the social condition); control (conditioned and non-conditioned pairs alone). The main results was that only the conditioned individuals modified their food choice, consuming significantly more of the spontaneously preferred food during the pairs interacting and pairs separated conditions, but not during the control condition.

Aging↗

Differences in aerial and terrestrial visual scanning in captive black tufted-ear marmosets (Callithrix penicillata) exposed to a novel environment.

Aerial and terrestrial visual scanning were investigated in captive black tufted-ear marmosets, Callithrix penicillata, exposed to a novel environment. Naive adult subjects (n=24) were individually exposed to a figure-eight maze during seven 30-min trials, 48 h apart. Habituation to the maze was observed, as indicated by the significant decrease in locomotion. The frequency of aerial scanning, however, remained elevated throughout the 7 trials, while its duration rapidly increased to high levels. Frequency and duration of terrestrial scanning persisted at constant low rates, differing significantly from aerial scanning. Males and females did not differ significantly. The different impact of aerial versus terrestrial predators could have a significant influence on vigilant behaviour in this species. Thus, visual scanning is an important and highly organized antipredation strategy in marmosets.

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Two breeding females within free-living groups may not always indicate polygyny: alternative subordinate female strategies in common marmosets (Callithrix jacchus).

The mating system of callitrichids has been reported to be monogamous, polygynous and polyandrous. In Callithrix jacchus, groups with 2 breeding females and groups with 1 breeding female have been reported. Our purpose was to evaluate the occurrence of occasional reproduction by subordinate females in free-ranging C. jacchus groups characterized as monogamous. Four groups were monitored at a field site of IBAMA-Brazil for between 20 and 72 months. We recorded the birth of 7 sets of twins to subordinate females that had never reproduced before. Sexual activities were recorded opportunistically: dominant females copulated with only the resident male, while subordinates copulated with extra-group males. We suggest these were essentially monogamous groups that occasionally had 2 reproductive females. Between-group copulations seem to be an alternative strategy used by the subordinates. Despite the costs, there would probably be benefits as a result of scanning for vacancies for reproductive positions in neighbouring groups and the establishment of ties with extra-group males that might become a reproductive partner in the future.

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Analysis of constitutive heterochromatin by fluorochromes and in situ digestion with restriction enzymes in species of the group Callithrix argentata (Callitrichidae, Primates).

The karyotypes of the species belonging to the group Callithrix argentata (Callitrichidae, Platyrrhini) are characterized by large amounts of distal constitutive heterocharomatin (CH). The CH of the species C. argentata, C. humeralifera and C. emiliae was analyzed by banding with the restriction enzymes HinfI, MboI, aluI, RsaI, DdeI, HaeIII and MspI, as well as the fluorochromes CMA3 and DAPI. The results obtained permitted us to classify the CH of these species into three distinct types: 1) distal CH with a homogeneous response to enzymatic action, which was unchanged (HinfI, MboI, AluI, HaeIII), partially digested (DdeI) or fully digested (RsaI), being CMA3+, DAPI-; 2) centromeric CH, generally presenting a reduced band size. The varying extent of reduction, ranging from none to total, and also the variation of fluorochrome staining indicates that there is heterogeneity in this type of CH; 3) CH of the distal portion of the X chromosome of C. argentata and of the Y chromosome was CMA3- and unchanged by the enzymes, except for RsaI, which caused a reduction in size. MspI was the only enzyme unable to induce bands. Sequential C-banding permitted us to perceive banding variations that could not be observed simply by RE banding.

Animals↗

Chromosomal relationships and phylogenetic and clustering analyses on genes Callithrix group argentata (Callitrichidae, Primates).

The karyotypes of three species of marmosets of the Callithrix argentata group (C. argentata, C. humeralifera and C. chrysoleuca) were studied. Comparisons were made among species and with the previously described karyotypes of C. emiliae, C. mauesi (argentata group) and C. jacchus (jacchus group). Two chromosomes rearrangements differentiate the argentata (2n=44) and jacchus (2n=46) groups: fusion or fission and a paracentric invasion. The argentata group is also characterized by the addition of large amounts of distal constitutive heterochromatin (CH) in some chromosomes, while the jacchus group shows mainly centromeric heterochromatin. The five species of the argentata group differ in the amount or location of the distal CH. Interspecific differences were converted to a Basic Data Matrix (BDM), that was submitted to phenetic and cladistic analyses. For cladistic analyses C. jacchus was the outgroup. The results agree with morphological and geographical data.

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Cytoarchitecture of the oculomotor nuclear complex and of the trochlear nucleus in the marmoset (Callithrix jacchus).

The cytoarchitecture of the oculomotor nuclear complex (ONC) and of the trochlear nucleus (TN) was studied in the encephalon of 10 adult marmosets (Callithrix jacchus). All the encephala were fixed with Bouin, embedded in paraffin and submitted to 20-mum serial sections in the transversal, frontal and horizontal directions. The following staining methods were employed: Nissl, Kluver-Barrera, and Pal-Weigert, modified by Erhart [1951]. Morphologically we delimited four cell columns in the ONC of the marmoset, namely lateral, dorsal, anterior, and dorsal central. The lateral and dorsal central columns comparatively correspond, in man, to the somatic portion. The others to the visceral portion. The trochlear nucleus of the marmoset is compact, round in shape and can be divided in to central cellular, dorsoventral and ventrolateral groups. The neurons of both the nuclei, of the multipolar type, predominantly have a round shape but it is also possible to observe oval or triangular neurons. They have a central nucleus, the Nissl substance is not dense and is irregularly disposed. Some differences in the size of neurons can be observed among the columns of the ONC.

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