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Concept: Prosimian

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BACKGROUND: Hematologic and biochemical data are needed to characterize the health status of animal populations over time to determine the habitat quality and captivity conditions. Blood components and the chemical entities that they transport change predominantly with sex and age. The aim of this study was to utilize blood chemistry monitoring to establish the reference levels in a small prosimian primate, the Grey Mouse Lemur (Microcebus murinus). METHOD: In the captive colony, mouse lemurs may live 10-12 years, and three age groups for both males and females were studied: young (1-3 years), middle-aged (4-5 years) and old (6-10 years). Blood biochemical markers were measured using the VetScan Comprehensive Diagnostic Profile. Because many life history traits of this primate are highly dependent on the photoperiod (body mass and reproduction), the effect of season was also assessed. RESULTS: The main effect of age was observed in blood markers of renal functions such as creatinine, which was higher among females. Additionally, blood urea nitrogen significantly increased with age and is potentially linked to chronic renal insufficiency, which has been described in captive mouse lemurs. The results demonstrated significant effects related to season, especially in blood protein levels and glucose rates; these effects were observed regardless of gender or age and were likely due to seasonal variations in food intake, which is very marked in this species. CONCLUSION: These results were highly similar with those obtained in other primate species and can serve as references for future research of the Grey Mouse Lemur.

Concepts: Renal failure, Primate, Lemur, Mouse lemur, Cheirogaleidae, Gray Mouse Lemur, Prosimian

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One of the most disputed issues in primate evolution and thus of our own primate roots, is the phylogenetic position of the Southeast Asian tarsier. While much molecular data indicate a basal place in the primate tree shared with strepsirrhines (prosimian monophyly hypothesis), data also exist supporting either an earlier divergence in primates (tarsier-first hypothesis) or a close relationship with anthropoid primates (Haplorrhini hypothesis). The use of retroposon insertions embedded in the Tarsius genome afforded us the unique opportunity to directly test all three hypotheses via three pairwise genome alignments. From millions of retroposons, we found 104 perfect orthologous insertions in both tarsiers and anthropoids to the exclusion of strepsirrhines, providing conflict-free evidence for the Haplorrhini hypothesis, and none supporting either of the other two positions. Thus, tarsiers are clearly the sister group to anthropoids in the clade Haplorrhini.

Concepts: Primate, Phylogenetics, Tarsier, Strepsirrhini, Haplorrhini, Simian, Prosimian, Primates

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Among environmental factors that may affect on brain function, some nutrients and particularly n-3 polyunsaturated fatty acids (n-3 PUFA) are required for optimal brain development. Their effects on cognitive functions, however, are still unclear, and studies in humans and rodents have yielded contradictory results. We used a non-human primate model, the grey mouse lemur, phylogenetically close to human. The aim of this study was to demonstrate the impact of n-3 PUFA supplementation on cognitive functions, neuronal activity and neurogenesis. Two groups of animals whose diet was supplemented with either fish oil (rich in n-3 PUFA) or olive oil as a control. These two groups were subjected to a visual discrimination task and to a test of anxiety in the open-field. In parallel, cortical activity was measured with telemetric ECoG recordings. Finally, adult neurogenesis was investigated ex vivo by means of immunohistochemistry. Animals supplemented with fish oil exhibited better visual discrimination performance and tended to have lower anxiety levels. Furthermore, supplementation increased the power of alpha, beta and gamma frequency bands in the EEG, which are related to various aspects of memory and decision-making. This study also provides the first evidence of the existence of adult neurogenesis process in a prosimian primate. Notably, lemurs supplemented with n-3 PUFAs for 21 months exhibited a higher number of newly born neurons in brain areas related to memory and emotions, compared to control animals. Altogether, these results point to long-term positive effects of dietary n-3 PUFAs on various functions of the primate brain. Further studies will be needed to determine a formal causal link between behavioral improvement and creation of new neurons.

Concepts: Nutrition, Fatty acids, Essential fatty acid, Omega-3 fatty acid, Primate, Lemur, Mouse lemur, Prosimian

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The current investigation in macaque monkeys utilized long-train intracortical microstimulation to determine the extent of cortex from which movements could be evoked. Not only were movements evoked from motor areas (PMC and M1), but they were also evoked from posterior parietal (5, 7a, 7b) and anterior parietal areas (3b, 1, 2). Large representations of digit movements involving only the index finger (D2) and thumb (D1), were elicited from areas 1, 2, 7b, and M1. Other movements evoked from these regions were similar to ethologically relevant movements that have been described in other primates. These include combined forelimb and mouth movements and full hand grasps. However, many other movements were much more complex and could not be categorized into any of the previously described ethological categories. Movements involving specific digits, which mimic precision grips, are unique to macaques and have not been described in New World or prosimian primates. We propose that these multiple and expanded motor representations of the digits co-evolved with the emergence of the opposable thumb and alterations in grip type in some anthropoid lineages.

Concepts: Cerebrum, Macaque, Primate, Frontal lobe, Parietal lobe, Finger, Thumb, Prosimian

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Non-human primates would be particularly valuable in life sciences and biomedical research area. Gene-modified monkeys with gene overexpression or loss of function have been successfully generated with the rapid advance in gene manipulation technology such as lentivirus infection and programmable nucleases (ZFN, TALEN, CRISPR-Cas9). Here we review the recent development on gene-modified monkey generation by lentivirus and programmable nucleases. Then we discuss three concerns, the long time for sexual maturation, the off target and the mosaicism of founders, which limit the wide application of gene-modified non-human-primates. At last, hotspots and future trend for gene-modified non-human-primates generation are proposed.

Concepts: DNA, Human, Primate, Ape, Strepsirrhini, Monkey, Simian, Prosimian

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Play fighting is a commonly reported form of play that involves competitive interactions that generally do not escalate to serious fighting. Although in many species what are competed over are the body targets that are bitten or struck in serious fighting, for many others, the competition can be over other forms of contact, such as sex, social grooming, and predation. In primates, the most detailed studies have been of species such as Old World monkeys, that engage in play fighting that simulates serious fighting, but reports of a number of others, especially among nocturnal prosimians, have noted that play fighting can also involve simulation of sex and grooming. The present study on captive born gray mouse lemurs (Microcebus murinus) provides a quantitative assessment of the relative engagement by juveniles in play fighting involving agonistic and amicable targets. About 80% of play fighting involves competing to groom or mount one another, with a minority involving competing to bite. That these forms of play fighting may be distinct from one another is suggested by the finding that attack on one target does not lead to counterattack on another. The findings are discussed in terms of the evolution and mechanisms underlying play fighting in primates and more widely among animals. (PsycINFO Database Record

Concepts: Competition, Sociology, Primate, Lemur, Strepsirrhini, Mouse lemur, Prosimian, New World monkey

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Integration of the sphenoid and ethmoid bones during early postnatal development is poorly described in the literature. A uniquely prolonged patency of sphenoethmoidal synchondrosis, or prespheno-septal synchondrosis (PSept) has been attributed to humans. However, the sphenoethmoidal junction has not been studied using a comparative primate sample. Here, we examined development of the sphenoethmoidal interface using ontogenetic samples of Old and New World monkeys, strepsirrhine primates (lemurs and lorises), and a comparative sample of other mammals. Specimens ranging from late fetal to one month postnatal age were studied using histology, immunohistochemistry, and micro-computed tomography methods. Our results demonstrate that humans are not unique in anterior cranial base growth at PSept, since it is patent in all newborn primates. We found two distinctions within our sample. First, nearly all primates exhibit an earlier breakdown of the nasal capsule cartilage that abuts the orbitosphenoid when compared to non-primates. This may facilitate earlier postnatal integration of the basicranium and midface and may enhance morphological plasticity in the region. Second, the PSept exhibits a basic dichotomy between strepsirrhines and monkeys. In strepsirrhines, the PSept has proliferating chondrocytes that are primarily oriented in a longitudinal plane, as in other mammals. In contrast, monkeys have a convex anterior end of the presphenoid with a radial boundary of cartilaginous growth at PSept. Our findings suggest that the PSept acts as a “pacemaker” of longitudinal facial growth in mammals with relatively long snouts, but may also contribute to facial height and produce a relatively taller midface in anthropoid primates. This article is protected by copyright. All rights reserved.

Concepts: Childbirth, Primate, Postnatal, Lemur, Strepsirrhini, Simian, Prosimian, New World monkey

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Hypothalamic-pituitary-adrenal (HPA) axis activity under different social settings in non-human primates is understudied.

Concepts: Human, Primate, Hominidae, Ape, Strepsirrhini, Monkey, Simian, Prosimian

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Bony structure of the postorbital region is a key trait distinguishing major clades of primates. Strepsirrhines share a postorbital bar, and anthropoids share a complete postorbital septum. At issue is whether the partial postorbital septum of tarsiers unites living tarsiers more closely with anthropoids than with certain large-eyed Eocene fossils. Previously we reported incomplete postorbital closure in tarsiers at birth. In this article, we document comparative analyses of the postorbital region in a broad range of perinatal primates. Virtual reconstructions of microCT data were used to study three-dimensional structure of the perinatal cranium in these taxa. We also describe and illustrate formation of the tarsier partial postorbital septum through the perinatal period using a growth series of Tarsius syrichta. Our results support the hypothesis that partial postorbital septation in the tarsier is secondary to eye hypertrophy. Based on these observations, we propose a structural hypothesis for phylogenetic differences observed in the primate postorbital region. Specifically, we propose that key postorbital traits, including the frontal spur in strepsirrhines and the posterior lamina of the zygomatic in anthropoids, develop as a result of the spatial relationships of brain, eyes, and teeth. Haplorhines are united by expansion of the anterior cranial fossa and loss of the frontal spur. Anthropoids are further united to the exclusion of tarsiers by expansion of the temporal lobes and associated formation of the posterior lamina of the zygomatic. Mechanical forces related to these spatial relationships may be modulated by deep fascia of the orbit to induce formation of the postorbital septum. Anat Rec, 299:1631-1645, 2016. © 2016 Wiley Periodicals, Inc.

Concepts: Skull, Primate, Tarsier, Strepsirrhini, Haplorrhini, Simian, Prosimian, Philippine Tarsier

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Head immobilisation is often necessary for neuroscientific procedures. A number of Non-invasive Head Immobilisation Systems (NHIS) for monkeys are available, but the need remains for a feasible integrated system combining a broad range of essential features.

Concepts: Human, Primate, Hominidae, Ape, Strepsirrhini, Monkey, Simian, Prosimian