Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PRIMATES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1993

Non-human primates used in studies of periodontal disease pathogenesis: a review of the literature.

The inability to examine initiation and progression of periodontal disease and to assess certain therapies in humans has led to a great interest in the use of animal models in periodontal research. Some of the most prominent animals used are non-human primates. This article reviews the characteristics of non-human primate models in periodontal health, in the transition from health to gingivitis to periodontitis, and in experimental gingivitis and periodontitis. Where possible, the results of these studies are compared with results from human studies. Only a few studies have compared in detail the anatomy, physiology, immunology, and tissue interactions in monkeys with those of humans. With the exceptions of differences and variations in size of the dentition, the number of each tooth type as well as larger canines, presence of diastemata between anterior teeth, and an edge-to-edge relationship of the incisors, the dental and periodontal anatomy of non-human primates seem quite similar to that of humans. Clinically healthy gingiva can be established and maintained in non-human primates, and gingivitis as well as periodontitis occur in these animals. It is possible to induce experimental periodontitis by placement of peri-dental silk ligatures or orthodontic elastics as well as by surgical removal of alveolar bone. Although the most appropriate model for studies of periodontal disease pathogenesis in non-human primates appears to involve the application of silk ligatures, some difficulties may occur in establishing periodontal break-down by using this model. Many clinical, histological, microbiological, and immunological characteristics of spontaneous and experimental marginal inflammation in most non-human primates are similar to those in humans. The most significant differences between small non-human primates and humans are the very limited number of lymphocytes and plasma cells in the inflammatory infiltrate of squirrel monkeys (Saimiri sciureus) and marmosets. Therefore, the use of squirrel monkeys and marmosets may not be appropriate in many studies of periodontal disease pathogenesis. The most significant microbial differences between macaque species and humans are a lower proportion of Actinomyces species, the presence of a catalase-producing Prevotella melaninogenica strain, and the high carrier rate for Actinobacillus actinomycetemcomitans in subgingival plaque of macaque species. The significance of these differences is presently unknown. It is concluded that the use of many non-human primate species due to the apparent close anatomic and biologic similarities to humans is appropriate in experimental studies of periodontal disease, provided the use of laboratory animals is requisite and lower species are not applicable.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2000

[Ecology and social organization of African tropical forest primates: aid in understanding retrovirus transmission].

The risk of transmission of primate viruses to humans is great because of their genetic proximity. It is now clear that the HIV group of retroviruses came from primates and that the origin of HIV1 is the chimpanzee subspecies of Central Africa, Pan troglodytes troglodytes. Many African primates are natural hosts of retroviruses and details of the natural history of both hosts and viruses are essential to understand the evolution of the latter. Data on the demography, ecology and behaviour of three species of primates (gorillas, chimpanzees and mandrills), studied in the Lopé Reserve in Central Gabon since 1983, are analysed to identify the factors that allow, or favour, disease transmission within each species, between different species and between primates and humans. The comparison of the relative degree of risk suggests that of the three species, chimpanzees are the most susceptible to exposure to infection both from conspecifics and from other species. With respect to humans, the comparative analysis suggests greater exposure to viruses of mandrills and gorillas than to those of chimpanzees. For primates, major risk factors are: large social groups; bites inflicted in fights; social grooming; and predation on mammals. However, given that contacts between social groups of the same species are rare, the spread of a virus through a population will be slow and uncertain. Hunting wild animals is the behaviour most likely to provide transmission routes for primate viruses into human populations because of the high probability of blood-blood contact. Not only the hunters themselves, but also women who prepare bush meat for cooking and people involved in trade of carcasses are at high risk of transmission of pathogens. Hunting of bush meat is increasing in Central Africa due to the economic recession and the spread of logging into the forests of the interior of the region. To counter the significant risk of transmission of known, as well as new, diseases from primates to humans, urgent measures are needed to attack the root causes of commercial hunting which is not only risk to public health but also a serious threat to biodiversity in the region.

Animals↗
PubMedDate not supplied

Predictive value of primate models for AIDS.

A number of obstacles remain in the search for an animal model for HIV infection and pathogenesis that can serve to predict efficacy in humans. HIV-1 fails to replicate and cause disease except in humans or chimpanzees, thereby limiting our ability to evaluate compounds or vaccines prior to human testing. Despite this limitation, nonhuman primate lentivirus models have been established that recapitulate the modes of infection, disease course, and antiviral immunity that is seen in HIV infection of humans. These models have been utilized to understand key aspects of disease and to evaluate concepts in therapies and vaccine development. By necessity, animal models can only be validated after successful trials in humans and the determination of correlates of protection. Because the only vaccine product tested in phase III trials in humans failed to achieve the desired protective threshold, we are as yet unable to validate any of the currently used nonhuman primate models for vaccine research. In the absence of a validated model, many experts in the field have concluded that prophylactic vaccines and therapeutic concepts should bypass primate models, and rely solely upon the systematic testing of each individual and combined vaccine element in human phase I or I/II trials to determine their relative merits. Indeed, a large effort is underway to expand efforts to test all products as part of an international effort termed "The HIV Vaccine Enterprise", with major contributions from the Bill and Melinda Gates Foundation. This Herculean task could potentially be reduced if it were possible to utilize even partially validated nonhuman primate models as part of the screening efforts. The purpose of this article is to review the data from nonhuman primate models that have contributed to our understanding of lentivirus infection and pathogenesis, and to critically evaluate how well these models have predicted outcomes in humans. Key features of the models developed to date are described and their contributions to HIV pathogenesis, therapeutics, and vaccines, are compared. This analysis shows that many of the models at hand have yielded data on drug action and immune responses to vaccines that are congruent with clinical data. This finding suggests that primate models are valuable as adjunctive testing systems to prioritize future therapeutic and vaccine strategies. Nonhuman primate testing of vaccine approaches in particular has provided valuable information and can significantly enhance and accelerate the evaluation of novel concepts necessary to achieve acceptable levels of efficacy. Because major gaps remain in the quest for fully effective vaccines and therapies, it seems prudent to continue aggressive research programs in the nonhuman primate models.

AIDS Vaccines↗
PubMed1995

Comparative sequence analysis of cytokine genes from human and nonhuman primates.

Two major issues severely limit the studies of human recombinant cytokines/growth factors in nonhuman primates. First, assays and reagents specific for the detection and quantitation of human cytokines do not all function when utilized to detect/quantitate the nonhuman primate cytokines. Second, although most of the human cytokines appear to induce similar, if not identical, biologic function when used with cells from nonhuman primates in vitro or in vivo, they invariably induce Ab responses in vivo, precluding their repeated and/or continued use in vivo. Our laboratory has thus initiated studies to clone, sequence, and prepare recombinant cytokines from nonhuman primates and to define assays and reagents for their detection and quantitation at the nucleic acid and protein level. The data that were derived from such studies show that the nonhuman primate cytokines IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 alpha, IL-12 beta, IL-15, IFN-alpha, IFN-gamma, and TNF-alpha share 93 to 99% homology at the nucleic acid and protein level with the human equivalents. The most prominent differences between human and nonhuman primate cytokine sequences were noted for IL-1 alpha/beta, IL-2, IL-8, IFN-alpha, IFN-gamma, and IL-12 beta. The aligned sequences of cytokines for human and several nonhuman primate species are provided herein, and a phylogenetic analysis of the published sequences of select cytokines from other species, along with those of the nonhuman primates, are described. In addition, comparative analysis of the relative bioactivity of our immunoaffinity-purified recombinant rhesus macaque IL-4, IL-15, and IFN-gamma with commercially available human recombinant cytokines is described herein.

Amino Acid Sequence↗
PubMed1978

The neuroanatomical organization of pathways between the dorsal lateral geniculate nucleus and visual cortex in Old World and New World primates.

Pathways between the dorsal lateral geniculate nucleus (dLGN) and visual cortex in Old World (Macaca, Papio, Erythrocebus, Cercopithecus) and New World (Saimiri, Cebus) primates were studied after injections of horseradish peroxidase and H3 or S35 amino acids into the dLGN or visual cortex. Trans-synaptic autoradiography was also used to study these pathways after an injection of H3 proline-fucose into one eye. The subsequent autoradiographs of visual cortex showed that Old World primates have separate eye inputs (ocular dominance columns) in the striate cortex, whereas New World monkeys have overlapping or non-separated eye inputs. In both primate groups the geniculocortical input to layer IVA formed a pattern which resembled a honeycomb in tangential sections, unlike the solidly labeled layer IVC. Also common to the two primate groups was a projection from dLGN to layer VI. There was no dLGN projection to any prestriate area in any of the primates. However, after an injection limited to the prestriate cortex of Macaca, light autoradiographic labeling was seen in the interlaminar zones and the magnocellular and S laminae, demonstrating a prestriate-dLGN pathway. Our results indicate that the primate visual system differs significantly from the cat in having no dLGN projection to area 18. There are also signficant differences between primates in the level at which the possibility of binocularity (of an excitatory nature) first occurs in the striate cortex because in the species studied thus far with neuroanatomical methods, Old World primates have ocular dominance columns in layer IV but most New World monkeys lack them.

Animals↗
PubMed1981

The topography of primate retina: a study of the human, bushbaby, and new- and old-world monkeys.

The distribution of ganglion cells has been studied in the retinas of four primates: the prosimian bushbaby, the New-World squirrel monkey, the Old-World crab-eating cynamolgous monkey, and the human. The sizes of ganglion cell somas were also measured at a number of retinal locations and compared with similar measurements in the cat retina to test for the presence in primates of retinal specializations such as the visual streak, and for gradients in retinal structure, such as that between temporal and nasal retina. In all four primates, ganglion cell somas in peripheral retina ranged considerably in diameter (6-16 micrometer in the bushbaby, 8-22 micrometer in the squirrel monkey, 8-23 micrometer in the cynamolgous monkey, 8-26 micrometer in the human). It seems likely that the strong physiological correlates of soma size which have been described among cat retinal ganglion cells and among the relay cells of the macaque lateral geniculate nucleus are generally present in primates. In all four primates, evidence was also obtained of a visual streak specialization; the isodensity lines in ganglion cell density maps were horizontally elongated, and small-bodied ganglion cells were relatively more common in the region of the proposed streak than in other areas of peripheral retina. However, the visual streak seems less well developed than in the cat; among the four primate species examined it was best developed in the bushbaby, at least as assessed by the shape of the isodensity lines. All four primates showed a clear foveal specialization, but this feature seemed least developed in the bushbaby. At the fovea, ganglion cells are smaller in soma size than in peripheral retina; they also seemed more uniform in size, although some distinctly larger cells persist in the human and bushbaby. Soma size measurements also provided evidence of a difference between nasal and temporal areas of peripheral retina comparable to that reported for the cat and other species. Thus the primate retinas examined show features, such as the foveal specialization, which seem unique to them among mammals. They also show features, such as nasal-temporal differences in ganglion cell size, and (though weakly developed) a visual streak, which they have in common with other mammals with widely different phylogenetic histories.

Animals↗
PubMed1996

Theories of visual cortex organization in primates: areas of the third level.

This brief review has a few main points. (1) Early proposals on how extrastriate cortex is subdivided were inconsistent with each other, and differences in interpretation were not resolved. (2) Brodmann's proposal of two ring-like areas, 18 and 19, surrounding primary visual cortex gained great acceptance despite the lack of agreement among different investigators considering the same evidence. (3) The concepts of areas 18 and 19, transposed to signify V2 and V3, have had great impact on recent and even current theories of extrastriate visual cortex organization in primates. (4) Nevertheless, Brodmann's areas 18 and 19, as defined in humans and Old World monkeys, correspond to none of the fields currently proposed for these primates. (5) All or most mammals appear to have a V2, and there is now widespread complete agreement over the extent and organization of this area in all studied primates. V2 is commonly referred to as area 18 because of its correspondence to area 18 as defined by Brodmann is some mammals. Yet, we should recognize that V2 is about half the size of Brodmann's area 18 in Old World monkeys and humans. (6) Current concepts of V3 differ greatly from the ring-like area 19 of Brodmann. We question the validity and usefulness of retaining the concept of V3 in primates. Our proposal for DM and other visual areas along the outer border of V2 seems more consistent, not only with the evidence from New World monkeys, but with evidence from Old World and prosimian primates, and even mammals most closely related to primates (see Kaas and Preuss, 1993). In all of these primates and close relatives of primates, the evidence indicates that more than one field forms the outer border of V2.

Animals↗
PubMed2003

A novel family of tRNA-derived SINEs in the colugo and two new retrotransposable markers separating dermopterans from primates.

Short interspersed nuclear elements (SINEs) provide a near homoplasy free and copious source of molecular evolutionary markers with precisely defined character polarity. Used as molecular cladistic markers in presence/absence analyses, they represent a powerful complement to phylogenetic reconstructions that are based on sequence comparisons on the level of nucleotide substitutions. Recent sequence comparisons of large data sets incorporating a broad eutherian taxonomic sample have led to considerations of the different primate infraorders to constitute a paraphyletic group. Statistically significant support against the monophyly of primates has been obtained by clustering the flying lemur-also termed colugo-(Cynocephalus, Dermoptera) amidst the primates as the sister group to anthropoid primates (New World monkeys, Old World monkeys, and hominoids). We discovered retrotransposed markers that clearly favor the monophyly of primates, with the markers specific to all extant primates but definitively absent at the orthologous loci in the flying lemur and other non-primates. By screening the colugo genome for phylogenetic informative SINEs, we also recovered a novel family of dermopteran specific SINE elements that we call CYN. This element is probably derived from the isoleucine tRNA and appears in monomeric, dimeric, and trimeric forms. It has no long tRNA unrelated region and no poly(A) linker between the monomeric subunits. The characteristics of the novel CYN-SINE family indicate a relatively recent history. Therefore, this SINE family is not suitable to solve the phylogenetic affiliation between dermopterans and primates. Nevertheless it is a valuable device to reconstruct the evolutionary steps from a functional tRNA to an interspersed SINE element.

Animals↗
PubMed1997

Determinants of primate social organization: comparative evidence and new insights from Malagasy lemurs.

The aim of this review is to summarize newly available information on lemur social systems, to contrast it with the social organization of other primates and to relate it to existing models of primate social evolution. Because of their evolutionary history, the primates of Madagascar constitute a natural experiment in social evolution. During millions of years of isolation, they converged with other primates only in the most fundamental way in the evolution of solitary, pair-living and group-living species, but deviate in several respects within these basic categories of social organization. Solitary lemurs remain poorly studied, but their social organization appears to be broadly similar to that of other solitary primates, even though the unexpected lack of sexual dimorphism may indicate that similar types of social organization can give rise to different mating systems. The determinants of a solitary lifestyle remain elusive. Pair-living lemurs show striking convergences with other monogamous primates in several behavioural traits, but also deviate in that the majority of species are at least partly nocturnal and do not exhibit direct paternal care of dependent young. Group-living lemurs have not evolved single-male groups, male-bonded and multi-level societies, and polyandrous groups may also be lacking. Female philopatry is common, but female bonds are generally weakly developed and eviction of females from natal groups is not unusual. Group-living lemurs also differ from anthropoids in that their groups have even adult sex ratios, smaller average size and may split up on a seasonal basis. Feeding competition, predation risk and reproductive competition can not fully explain these unusual aspects of lemur social organization. It has therefore been suggested that the social consequences of the risk of infanticide and of recent changes in activity may be ultimately responsible for these idiosyncracies of group-living lemurs, an explanation largely supported by the available evidence. Thus, social factors and fundamental life-history traits, in addition to ecological factors, contribute importantly to variation in social systems among lemurs, and possibly other primates. However, neither the diversity of lemur social systems, nor the evolutionary forces and mechanisms operating in these and other primates are yet fully understood.

Animals↗
PubMed1989

A comparative review of the primate motor system.

Primates have evolved separately from other mammals since the late Cretaceous, and during this time the two major extant primate groups, prosimians (lorises, lemurs, and tarsiers) and anthropoids (monkeys, apes, and humans) arose. Concurrently, structures within the central nervous system acquired primate characteristics. Not all of the uniquely primate features have been identified in the brain, but several are well known. The pyramidal system, the best studied motor system, shows a distinct primate pattern in its terminal connections in the spinal cord. Other descending systems are less well known, but primate specializations in the vestibular system and red nucleus have been observed. The primary and secondary motor cortices are topographically separated in primates, suggesting one basis for increased complexity. Given the size of the brain, structures in the basal ganglia are relatively enlarged in primates as compared with other mammals, whereas the cerebellum has the same relative size.

Journal Article↗
PubMed2003

Structure and function of CC-chemokine receptor 5 homologues derived from representative primate species and subspecies of the taxonomic suborders Prosimii and Anthropoidea.

A chemokine receptor from the seven-transmembrane-domain G-protein-coupled receptor superfamily is an essential coreceptor for the cellular entry of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) strains. To investigate nonhuman primate CC-chemokine receptor 5 (CCR5) homologue structure and function, we amplified CCR5 DNA sequences from peripheral blood cells obtained from 24 representative species and subspecies of the primate suborders Prosimii (family Lemuridae) and Anthropoidea (families Cebidae, Callitrichidae, Cercopithecidae, Hylobatidae, and Pongidae) by PCR with primers flanking the coding region of the gene. Full-length CCR5 was inserted into pCDNA3.1, and multiple clones were sequenced to permit discrimination of both alleles. Compared to the human CCR5 sequence, the CCR5 sequences of the Lemuridae, Cebidae, and Cercopithecidae shared 87, 91 to 92, and 96 to 99% amino acid sequence homology, respectively. Amino acid substitutions tended to cluster in the amino and carboxy termini, the first transmembrane domain, and the second extracellular loop, with a pattern of species-specific changes that characterized CCR5 homologues from primates within a given family. At variance with humans, all primate species examined from the suborder Anthropoidea had amino acid substitutions at positions 13 (N to D) and 129 (V to I); the former change is critical for CD4-independent binding of SIV to CCR5. Within the Cebidae, Cercopithecidae, and Pongidae (including humans), CCR5 nucleotide similarities were 95.2 to 97.4, 98.0 to 99.5, and 98.3 to 99.3%, respectively. Despite this low genetic diversity, the phylogeny of the selected primate CCR5 homologue sequences agrees with present primate systematics, apart from some intermingling of species of the Cebidae and Cercopithecidae. Constructed HOS.CD4 cell lines expressing the entire CCR5 homologue protein from each of the Anthropoidea species and subspecies were tested for their ability to support HIV-1 and SIV entry and membrane fusion. Other than that of Cercopithecus pygerythrus, all CCR5 homologues tested were able to support both SIV and HIV-1 entry. Our results suggest that the shared structure and function of primate CCR5 homologue proteins would not impede the movement of primate immunodeficiency viruses between species.

Amino Acid Sequence↗
PubMed1994

Comparison of canine and non-human primate animal models for periodontal regenerative therapy: results following a single administration of PDGF/IGF-I.

Two commonly used animal models for evaluating putative periodontal regenerative therapies are the beagle dog model with natural periodontal disease and the non-human primate with ligature-induced attachment loss. The host response, microbiology, and skeletal rates of remodeling of these two models are summarized. In addition, the results of experiments comparing the healing response to periodontal surgery with and without concurrent use of the combination of platelet-derived growth factor (PDGF) and insulin-like growth factor-I (IGF-I) in these models are presented. At 1 month, PDGF/IGF-I administration resulted in a 64.1% and 51.4% increase in new attachment formation in the non-human primate and canine, respectively, while controls (surgery plus placebo) demonstrated 34.1% and 8.6% increases in new attachment formation in the non-human primate and canine models, respectively. Further, application of PDGF/IGF-I stimulated 21.6% and 65% osseous defect fill in the non-human primate and canine, respectively, while controls demonstrated 8.5% and 14.5% osseous defect fill in the non-human primate and canine, respectively. The osseous response in the canine appears greater than that of the non-human primate, and the new attachment formation was more substantial in the non-human primate than the canine. However, in general these data demonstrate a high degree of consistency in the effects of PDGF/IGF-I in promoting periodontal regeneration. Positive results in these two models--the dog with natural periodontal disease and the non-human primate with ligature-induced attachment loss--justify human clinical trial testing of a putative regenerative therapy.

Alveolar Bone Loss↗
PubMed1983

Selective myocardial cell necrosis in nonhuman primates.

A retrospective study was performed to describe the histologic stages of selective myocardial cell necrosis (SMCN) in nonhuman primates, and to compare the incidence of SMCN in two groups of nonhuman primates. Myocardial tissues taken at the time of autopsy from 50 primates at an experimental center were compared with similar tissues from 50 primates housed in a breeding colony. SMCN was confirmed in 20% of the experimental primates and 30% of the breeding primates, proportions that were not significantly different. The incidence and histologic characteristics of SMCN in nonhuman primates were similar to those described in humans, and resembled the lesion produced in experimental primates by administration of catecholamines of by hypokalemia.

Animals↗
PubMed2004

Parasites and the evolutionary diversification of primate clades.

Coevolutionary interactions such as those between hosts and parasites have been regarded as an underlying cause of evolutionary diversification, but evidence from natural populations is limited. Among primates and other mammalian groups, measures of host diversification rates vary widely among lineages, but comparative studies have not yet identified a reliable explanation for this variation. In this study, we used a comprehensive data set of disease-causing organisms from free-living primates to illustrate how phylogenetic comparative methods can be used to examine mammalian lineage diversity in relation to parasite species richness. Our results provide evidence that the phylogenetic diversity of primate clades is correlated positively with the number of parasite species harbored by each host and that this pattern is largely independent of other host traits that have been shown to influence diversification rates and parasite species richness in primates. We investigated two possible mechanisms that could explain this association, namely that parasites themselves drive host evolutionary diversification through processes linked with sexual selection and that host shifts or host sharing increases parasite species richness among diverse primate clades. Neither parasite species richness nor host diversification is related to measures of sexual selection in primates. Further, we found only partial evidence that more rapidly diversifying host lineages produced increased opportunities for host sharing or host shifting by parasites through mechanisms involving species' geographic range overlap. Thus, our analyses provide evidence for an important link between the evolutionary diversification of primates and the richness of their parasite communities, but other mechanisms, particularly those related to reciprocal selection or coextinction of hosts and parasites, require further investigation.

Animals↗
PubMed2000

Habitat alteration and the conservation of African primates: case study of Kibale National Park, Uganda.

Tropical forests and the animals they support are being threatened by accelerating rates of forest conversion and degradation. In a continually fluctuating sociopolitical world, it is often impossible to protect areas from such conversion until the political environment is suitable to pursue conservation goals, by which time, the forests have often been converted to other uses. This reality suggests a need for inquiry into which primate species can persist after different types of disturbances and how quickly primate communities can recover from disturbance. Here we examine the persistence of primate populations in disturbed habitats by providing a case study of patterns of primate abundance in areas of Kibale National Park (766 km2), Uganda, that have been modified by different types and intensities of human activities, primarily commercial logging and agricultural clearing. Distributional surveys at 24 sites and detailed line-transect censuses at six sites demonstrate that primate populations in Kibale are often high and suggest that patterns of population change associated with disturbance are complex. Analysis of the land use coverage of Kibale reveals that abandoned farms (10.3%) and degraded forest (8.7%) now cover 146 km2. Unfortunately, we do not know what proportion of the farms were established on areas that were forest versus grassland. However, if the areas that are now abandoned farms were all once forested, this means that 79 km2 of forest has been lost. Based on density estimates from nearby sites, this would represent a loss of 52,612 monkeys and 200 chimpanzees. Populations would also have been affected by the degradation of the 66 km2 (8.7%) of forest. These estimates of the potential reductions in the primate populations that could have resulted from forest clearing and degradation illustrate the importance of protecting land. A review of the literature illustrates that the biomass of primates found within Kibale is very high in comparison to other locations and thus illustrates the importance of Kibale to regional conservation.

Agriculture↗
PubMed2005

Primate assemblage structure in Amazonian flooded and unflooded forests.

There is considerable variation in primate species richness across neotropical forest sites, and the richest assemblages are found in western Amazonia. Forest type is an important determinant of the patterns of platyrrhine primate diversity, abundance, and biomass. Here we present data on the assemblage structure of primates in adjacent unflooded (terra firme) and seasonally inundated (várzea and igapó) forests in the lower Purús region of central-western Brazilian Amazonia. A line-transect census of 2,026 km in terra firme, 2,309 km in várzea, and 277 km in igapó was conducted. Twelve primate species were recorded from 2,059 primate group sightings. Although terra firme was found to be consistently more species-rich than várzea, the aggregate primate density in terra firme forest was considerably lower than that in the species-poor várzea. Consequently, the total biomass estimate was much higher in várzea compared to either terra firme or igapó forest. Brown capuchin monkeys (Cebus apella) were the most abundant species in terra firme, but were outnumbered by squirrel monkeys (Saimiri cf. ustus) in the várzea. The results suggest that floodplain forest is a crucial complement to terra firme in terms of primate conservation in Amazonian forests.

Animals↗
PubMed2000

Micro-anatomy of the volar skin and interordinal relationships of primates.

Paleontological and molecular evidence have been employed to suggest that flying lemurs (Dermoptera) and primates form a monophyletic group, in sharp contrast with cranial and postcranial evidence indicating sister group relationships between flying lemurs and bats (Chiroptera). New evidence from the epidermis of the volar pads of primates, tree shrews, flying lemurs, bats, and other mammals was examined and mapped on to various hypotheses of archontan relationships. The micro-anatomy of the skin on the palm and sole of flying lemurs and bats differs fundamentally from that of tree shrews (Scandentia) and primates. The volar skin of flying lemurs and bats lacks the serial arrangement of papillary ridges and grooves ("fingerprints") found in primates, tree shrews, and many other mammals. Moreover, the junction between the epidermis and dermis in flying lemurs and bats is relatively flat and shows little or no development of the internal ridges that occur in primates and tree shrews. When mapped on to a set of cladograms of mammals currently allocated to the superorder Archonta, this new evidence does not support sister group relationships between flying lemurs and primates, regardless of the volar skin morphology that characterized the last common ancestor of Archonta. Micro-anatomical differences that distinguish the volar skin of flying lemurs and bats from that of primates and tree shrews reflect a profound dichotomy in the functional roles fulfilled by the extremities, which could be significant in a phylogenetic context.

Animals↗
PubMed2000

Molecular evolution of cytochrome c oxidase subunit I in primates: is there coevolution between mitochondrial and nuclear genomes?

Phylogenetic analyses carried out on cytochrome c oxidase (COX) subunit I mitochondrial genes from 14 primates representing the major branches of the order and four outgroup nonprimate eutherians revealed that transversions and amino acid replacements (i.e., the more slowly occurring sequence changes) contained lower levels of homoplasy and thus provided more accurate information on cladistic relationships than transitions (i.e., the more rapidly occurring sequence changes). Several amino acids, each with a high likelihood of functionality involving the binding of cytochrome c or interaction with COX VIII, have changed in Anthropoidea, the primate suborder grouping New World monkey, Old World monkey, ape, and human lineages. They are conserved in other mammalian lineages and in nonanthropoid primates. Maximum-likelihood ancestral COX I nucleotide sequences were determined utilizing a near most parsimonious branching arrangement for the primate sequences that was consistent with previously hypothesized primate cladistic relationships based on larger and more diverse data sets. Relative rate tests of COX I mitochondrial sequences showed an elevated nonsynonymous (N) substitution rate for anthropoid-nonanthropoid comparisons. This finding for the largest mitochondrial (mt) DNA-encoded subunit is consistent with previous observations of elevated nonsynonymous substitution/synonymous substitution (S) rates in primates for mt-encoded COX II and for the nuclear-encoded COX IV and COX VIIa-H. Other COX-related proteins, including cytochrome c and cytochrome b, also show elevated amino acid replacement rates or N/S during similar time frames, suggesting that this group of interacting genes is likely to have coevolved during primate evolution.

Amino Acid Sequence↗