Histochemical observations on the taste buds of the marmosets (Callithrix jacchus and Callithrix penicillata).

The epithelial cells in the taste buds of C. jacchus and C. penicillata show a moderate amount of ribonucleic acid an a concentration of a PAS-positive diastase-resistant material at their apical part. These cells are devoid of UDPG-GT, phosphorylases, G-6-PA, alanyl aminopeptidase, leucine aminopeptidase, cholinesterase and MAO; they present a weak reaction of F-1, 6-P Ald, LDH, SDH, MDH, cytochrome oxidase, beta-OHBDH, nonspecific esterase and acid phosphatase and a stronger reaction to ADH, NADPH2-TR, ATPases, alpha-GPDH, alkaline phosphatase, 5-nucleotidase and GDH. Although some enzymes (alkaline phosphatase, 5-nucleotidase and ATPases) have an almost uniform reactivity by the several taste buds, the other ones react with a lesser intensity in the smaller uniform reactivity by the several taste buds, the other ones react with a lesser intensity in the smaller taste buds of the fungiform papillae. As a rule the apical part of the cells shows a stronger enzymatic reactivity. The taste buds of the marmosets are penetrated by acetylcholinesterase positive nerve fibers whereas the autonomic ganglia in the connective tissue contain both-acetyl and butyrylcholinesterase.     

Histochemical studies on the submandibular ganglia of marmosets (Callithrix jacchus and Callithrix penecillata).

The histochemistry of the neural cells was studied in the submandibular ganglia of 5 Callithrix jacchus (3 males and 2 females) and 4 Callithrix penicillata (2 males and 2 females). These cells contain neutral mucopolysaccharides, nucleoproteins and lipidic materia, but are apparently devoid of glycogen. It is impossible to demonstrate in them any reactivity for UDPG-GT, phosphorylases, ATPase at pH 6.3, leucine aminopeptidase and alanyl aminopeptidas. The reaction for the other searched enzymes was as follows: weak (F-1,6-P Ald and cytochrome oxidase), weak to moderate (ADH, 6-P-GDH, ICDH, SDH, MDH, alpha-GPDH and beta-OHBDH), moderate (G-6-PDH, F-1,6-PA, LDH and GDH), moderate to strong (ATPase at pH 7.4, nonspecific esterase and acid phosphatase) and strong (G-6-PA, NADH2,-TR, NADPH2-TR, ATPase at pH 8.5 and 9.4 and alkaline phosphatase).     

Histochemical localization of enzyme activity in the kidneys of male marmosets (Callithrix jacchus and Callithrix penicillata).

The distribution of several hydrolases and oxidoreductases was studied in the renal parenchyma of adult male marmosets (Callithrix jacchus and Callithrix penicillata). The oxidative enzymes showed a high reactivity in the proximal and distal tubules, whereas the hydrolases reacted strongly in the proximal tubules but only weakly or not at all in the thick limb of Henle's loop, distal tubules and collecting ducts. The NAD-dependent enzymes (except alpha-GPDH) showed a stronger reactivity in the proximal tubules, while the NADP-dependent ones were more reactive in the thick limb of Henle's loop and distal convoluted tubules. Two groups of interstitial cells were found in the medulla. A first group inside the outer medulla, showing cells rich in acid phosphatase and nonspecific esterases and a second group, close to the papilla, reactive to a certain number of oxidative enzymes. A different reactivity in cells of the distal convoluted tubules, thick limb of Henle's loops and collecting ducts (dark cells) was seen in the case of some enzymes like nonspecific esterase, alpha-GPDH and SDH.     

Cross-fostering between two species of marmosets (Callithrix jacchus) and Callithrix penicillata)

Cross-fostering technique can be defined as adoption of infants by adults of other species. This phenomenon is poorly investigated because very young animals have few opportunities to interact peacefully with non-conspecific adults, either in captivity or in natural conditions. This study describes the induction of cross-fostering in captivity between white tufted-ear (Callithrix jacchus) and black tufted-ear marmosets (Callithrix penicillata). We conclude that this technique can be very useful for preserving the life of rejected by parents or orphan infants, mainly in the case of species with low reproduction rate in captivity or those threatened by extinction, as well for investigating the environmental effects on the typical behavior of species (courtship, food preference, vocalization patterns, e.g.).     

Histochemical data on the liver of the marmoset (Callithrix jacchus).

The histochemistry of the hepatic parenchymal cells was studied in four Callithrix jacchus. A large amount of glycogen was noted throughout the lobules while the UDPG-GT and the phosphorylases were found unevenly distributed by the hepatic strands with different degrees of reactivity. Near the central vein one of the livers showed PAS-positive nuclear corpuscles that were more conspicuous in the hepatic cells with a larger amount of cytoplasmic glycogen and weaker UDPG-GT and phosphorylase reactivities. G-6PA (in a larger amount) and LDH (in a moderate amount) were found evenly distributed in the hepatic strands. F-1-6PA was seen sometimes with a stronger reactivity at the peripheral part of the lobules. The enzymes of the pentose shunt (G-6PDH, 6-PGDH and NADPH-2-TR) reacted strongly and as a rule evenly distributed near the hepatic lobules. Occasionally they reacted more intensely in the row of hepatic cells disposed just around the central vein. Cytochrome oxidase showed a very faint reaction. Cis-aconitase and ICDH were weak or moderate. NADH-2-TR more than SDH more than MDH were seen frequently diffused near the hepatic strands. SDH and MDH in some instances showed a stronger reactivity in the row or group of hepatic cells around the central vein. ATPase at pH 6.3 was negative in the marmoset liver; ATPase at pH 7.4 was mainly found in the wall of the portal area vessels; ATPase at pH 8.5 showed a stronger reactivity in the cytoplasm of the hepatic cells and ATPase at pH 9.4 was more abundant in the bile capillaries. The reactivity of the lipid metabolism enzymes was moderate with regard to alpha-GPDH or negligible with regard to beta-OHBDH. Acid phosphatase showed a stronger reaction, but almost limited to the Kupffer cells. The hepatic cells showed only a moderate amount of RNA. Some enzymes of the protein metabolism, such as GDH and leucine aminopeptidase showed a stronger reactivity while some others, such as alanyl aminopeptidase and MAO, were seen diffused near the hepatic lobules in a small amount. Enzymes of the mucopolysaccharide metabolism were not found at all (beta-glucuronidase) or showed only a weak reactivity, such as xylitol dehydrogenase.     

Post-conflict affiliation in common marmosets (Callithrix jacchus jacchus)

Post-conflict (PC) affiliation has been demonstrated in a number of Old World monkeys and apes, but very little is known about the occurrence of the phenomenon in New World monkeys. This study examined 282 PC interactions after spontaneous conflicts around feeding time in two family groups (N = 12) of captive common marmosets, Callithrix jacchus jacchus. We found an overall corrected conciliatory tendency of 31%. Selective attraction was seen: former opponents met significantly more often in PCs than in matched controls (MCs) (27% and 16%, respectively). There was no difference in the occurrence of PC affiliation between dyads consisting of parent-offspring constellations compared to offspring-offspring constellations. PC affiliative behaviors were seen in the first three minutes following conflict termination, and consisted mainly of proximity, play invitations, and food transfer. Notably, former opponents remained within arm's reach after 17% of conflicts. Affiliation was more likely to follow after conflicts involving play issues. The functional importance of the PC affiliation in marmosets remains to be examined.     

Hematology of common marmosets (Callithrix jacchus)

The hematology of the common marmoset (Callithrix jacchus) was investigated to provide reference values for the normal animal. Red blood cell counts, white blood cell counts, hemoglobins, mean cell volumes and differential white blood cell mean values were determined for Texas A&M colony-born animals and those obtained from the wild. The analyses were completed on 31 animals, three times each, for a total of 93 analyses, which included 16 colony-born and 15 wild-born marmosets. The hematological mean values found for marmosets were similar to those mean values reported for humans. The ranges for the hematology values were much narrower in the colony-born marmosets, and the average white blood cell count was significantly lower in these animals. This indicated that it is possible to produce and maintain a more uniform animal in the colony environment and, consequently, these animals are more suitable than wild-born animals for use as models for human research.     

Lymphocyte populations of Callithrix jacchus marmosets.

A lymphocyte population of common marmosets (Callithrix jacchus) was identified by rosette formation with African green monkey erythrocytes; the rosette-forming cells appeared to be T lymphocytes, as approximately 62% of circulating lymphocytes and 85% of thymus cells formed rosettes with African green monkey erythrocytes. In addition, common marmoset lymphoid cells carrying T-lymphotropic Herpesvirus saimiri or Herpesvirus ateles formed rosettes with African green monkey erythrocytes and treatment of common marmoset circulating lymphocytes with an anti-T cell serum and complement (C′) eliminated rosette-forming cells. Common marmoset T lymphocytes apparently carry a surface receptor for African green monkey erythrocytes, but unlike humans and other closely related nonhuman primates, T lymphocytes of common marmosets fail to form rosettes with sheep erythrocytes.     

Reproduction in captive common marmosets (Callithrix jacchus)

Though sexual maturation may begin at around one year of age, first successful reproduction of the common marmoset (Callithrix jacchus) is likely to be later, and it is generally recommended that animals not be mated before 1.5 years of age. The average gestation period is estimated to be 143 to 144 days. A crown-rump length measurement taken by use of ultrasonography during the linear, rapid, prenatal growth phase (between approx. days 60 and 95) can be compared against standard growth curves to estimate delivery date to within 3 to 4 days, on average. Marmosets produce more young per delivery than does any other anthropoid primate, and have more variation in litter size. Many long-established colonies report that triplets are the most common litter size, and there is documented association between higher maternal body weight and higher ovulation numbers. Higher litter sizes generally do not generate higher numbers of viable young. Marmosets are unusual among primates in having a postpartum ovulation that typically results in conception and successful delivery; reported median inter-birth intervals range from 154 to 162 days. However, pregnancy losses are quite common; one study of a large breeding colony indicated 50 percent loss between conception and term delivery. The average life span for breeding females is around six years; the range of reported average lifetime number of litters for a breeding pair is 3.45 to 4.0. Our purpose is to provide an overview of reproduction in the common marmoset, including basic reproductive life history, lactation and weaning, social housing requirements, and common problems encountered in the captive breeding of this species. A brief comparison between marmoset and tamarin reproduction also will be provided.     

Blood vitamin values of common marmosets (Callithrix jacchus)

The blood vitamin analyses of the common marmoset (Callithrix jacchus) were determined to provide baseline reference values for the normal animal. Ascorbic acid, riboflavin (erythrocyte glutathione reductase) [ECR], measurement, thiamin (erythrocyte transketolase) measurement and vitamin A (retinol) were determined for Texas A&M colony-born animals and those obtained from the wild. The analyses were completed on the animals, three times each, for a total of 93 analyses, which included 51 colony-born and 60 wild-born marmosets. A mean value of 0.98 mg/dl for ascorbic acid was found for the colony with a range from 0.06 to 4.1 mg/dl. The normal range for the marmosets appeared to be 0.5 to 1.5 mg/dl. The mean activity coefficient (AC) for the marmosets was 1.0 indicating that the animals had adequate riboflavin in the diet. The mean transketolase activities were (ribose remaining ?30.1 IU/L) and (sedoheptulose appearance ?7.9 IU/L). The mean and range for serum vitamin A (retinol) were 20.4 mg/dl and 6.96–57.44 mg/dl, respectively. None of the animals (colony-born or wild-born) exhibited any clinical signs of vitamin deficiencies as a result of being maintained in an indoor-outdoor environment over a three-year period.     

Sexual behavior and extragroup copulations in a wild population of common marmosets (Callithrix jacchus).

Sexual behavior and mating patterns are described for 3 free-ranging groups of common marmosets living in a coastal forest in northeastern Brazil. Each group contained 2 breeding females. Within groups, sexual behavior was generally restricted to breeding females and a single behaviorally dominant male. Of 101 mounts and copulations, 24 involved pairings of individuals from 2 different groups. Extragroup sexual behavior was performed by both breeding and nonbreeding group members, and 65% of all adults mounted or copulated with an extragroup individual at least once. Sexual behavior occurred throughout the female reproductive cycle but was significantly more frequent during an 11-day 'conception period'. Thus, while female marmosets show no physical signs of estrus, both males and females likely do have some information about the timing of ovulation. Mating patterns in this population included both polygyny and monogamy and varied between groups and over time.     

Scent marking and associated behaviour in captive Common marmosets (Callithrix jacchus jacchus) with a description of the histology of scent glands

The histological structure of the scent marking glands of Callithrix jacchus jacchus is described. Frequencies of scent marking were variable and bore no relation to reproductive states. Scent marking was temporally associated with sensory and piloerection behaviours. Possible functions of scent marking in C. J. jacchus are discussed.     

Individual olfactory signatures in common marmosets (Callithrix jacchus)

Individual discrimination is likely a prerequisite for most primate social interactions. Olfactory cues are one set of stimuli used by primates to discriminate between individuals. Despite the importance of these olfactory signatures, there is little published research assessing the existence or function of individually unique odors among primates. This review systematically assesses behavioral and biochemical aspects of individual odors in a New World primate, the common marmoset (Callithrix jacchus). There are three objectives to this review: First, behavioral evidence for odors unique to the individual is evaluated in the context of results demonstrating that marmosets are able to discriminate between the scents from a familiar and a novel individual conspecific in behavioral bioassays under a variety of conditions. Second, biochemical evidence for individual scent signatures is debated with reference to studies examining qualitative and quantitative differences between the chemical compositions of scent-mark pools from adult females. A combined gas chromatography (GC) and mass spectrometry (MS) analysis demonstrated that each female had a unique ratio of highly volatile chemicals in the scent mark that could affect individual discrimination. Finally, the possible adaptive significance of individual odors in marmosets is debated. Individual odors may play a key role in regulating both female intrasexual competition and intersexual communication by providing a basis for the assessment of individual quality.     

Pregnancy diagnosis in the common marmoset (Callithrix jacchus jacchus).

Abdominal palpation of the uterus was carried out on 25 pregnant and 29 non-pregnant marmosets (Callithrix jacchus jacchus). 195 complete 24-hour urine specimens, collected between the first week of gestation and term (21 weeks), were tested with the Sub-Human Primate Tube (SHPT) test. No significant differences between the two methods in their ability to diagnose pregnancy were obtained between the first and 13th week of gestation. The SHPT test was seldom positive after the 13th week of pregnancy, whereas, with one exception, palpation always indicated pregnancy.