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At least 793 records · Page 44Linked to original sources
PubMed2002

Complete genomic sequence of an Epstein-Barr virus-related herpesvirus naturally infecting a new world primate: a defining point in the evolution of oncogenic lymphocryptoviruses.

Callitrichine herpesvirus 3 (CalHV-3) was isolated from a B-cell lymphoma arising spontaneously in the New World primate Callithrix jacchus, the common marmoset. Partial genomic sequence analysis definitively identified CalHV-3 as a member of the Epstein-Barr virus (EBV)-related lymphocryptovirus (LCV) genus and extended the known host range of LCVs beyond humans and Old World nonhuman primates. We have now completed the first genomic sequence of an LCV infecting a New World primate by describing the unique short region, the major internal repeat, and a portion of the unique long region. This portion of the genome contains the putative latent origin of replication and 13 additional open reading frames (ORFs), 5 of which show no homology to any viral or cell genes. One of the novel genes, C5, is a positional homologue for the transformation-essential EBV gene EBNA-2. The marmoset LCV genome is also notable for the absence of viral interleukin-10 and small nonpolyadenylated RNA homologues. Marmoset LCV transcripts encoding putative latent infection nuclear proteins have a common leader sequence that is spliced from the major internal repeat in a manner similar to that of the EBV EBNA-LP, suggesting strong conservation of a common promoter and splicing of these latent infection mRNAs. An EBV LMP2A-like spliced transcript crossing the terminal repeats encodes a unique ORF, C7, with multiple transmembrane domains and tyrosine kinase phosphorylation sites functionally reminiscent of EBV LMP2A. However, the carboxy-terminal location of the candidate phosphotyrosine residues is more reminiscent of the Kaposi's sarcoma-associated herpesvirus K15 gene and provides potential evidence of an evolutionary transition from rhadinoviruses to lymphocryptoviruses. The unusual gene repertoire of the marmoset LCV differentiates ancestral viral genes likely present in an LCV progenitor from viral genes acquired later as primates and LCV coevolved, providing a defining point in the evolution of oncogenic LCVs.

Amino Acid Sequence↗
PubMed2004

Conservation of a stepwise, energy-sensitive pathway involving HP68 for assembly of primate lentivirus capsids in cells.

Previously we have described a stepwise, energy-dependent pathway for human immunodeficiency virus type 1 (HIV-1) capsid assembly in a cell-free system. In this pathway, Gag polypeptides utilize the cellular factor HP68 and assemble into immature capsids by way of assembly intermediates that have defined biochemical characteristics. Here we address whether this pathway is universally conserved among primate lentiviruses and can be observed in mammalian cells. We demonstrate that HIV-2 Gag associates with human HP68 in a cell-free system and that Gag proteins of HIV-2, simian immunodeficiency virus SIVmac239, and SIVagm associate with endogenous HP68 in primate cells, as is seen for HIV-1. Analysis of primate cells expressing lentivirus Gag proteins revealed Gag-containing complexes with the same sedimentation values as seen for previously described HIV-1 assembly intermediates in the cell-free system (10S, 80-150S, and 500S). These complexes fit criteria for assembly intermediates as judged by energy sensitivity, pattern of HP68 association, and the failure of specific complexes to be formed by assembly-incompetent Gag mutants. We also demonstrate that virus-like particles released from cells do not appear to contain HP68, suggesting that HP68 is released from Gag upon completion of capsid assembly in cells, as was observed previously in the cell-free system. Together these findings support a model in which all primate lentivirus capsids assemble by a conserved pathway of HP68-containing, energy-dependent assembly intermediates that have specific biochemical features.

ATP-Binding Cassette Transporters↗
PubMed1996

Site and parameters of microstimulation: evidence for independent effects on the properties of saccades evoked from the primate superior colliculus.

1. Microstimulation is used to investigate how activity in the superior colliculus (SC) contributes to determining the properties of primate saccadic eye movements. The site of collicular stimulation, the duration of the stimulation train, and the frequency of the stimulation train are each varied to examine the relative contributions of the locus, duration, and level of collicular activity to determining saccade amplitude, direction, duration, and velocity. 2. For any given site of stimulation, a relationship between movement amplitude and train duration can be demonstrated. Movement amplitude is a monotonically increasing, but saturating, function of increasing train duration. The size of the largest movement is dictated by the site of stimulation. Within the range over which amplitude can be modulated, movement offset is linked to the offset of the stimulation train. As a result, each decrement or increment in train duration produces a corresponding decrement or increment in movement duration. 3. The peak velocity of an evoked movement is influenced by the frequency of stimulation; a higher frequency of stimulation produces a movement of higher velocity. 4. The effects of train duration and frequency can be traded to produce movements that have comparable amplitudes but different dynamic characteristics; high-velocity movements of short duration and low-velocity movements of long duration can be produced by stimulating with high-frequency, short-duration, and low-frequency, long-duration trains, respectively. Across stimulation frequencies, the amplitude of an evoked movement is best related to the total number of pulses in the stimulation train. 5. Because it is possible to compensate for reduced velocity by increasing the duration of the stimulation train, the same site-specific maximum amplitude can be attained with different frequencies of stimulation. 6. Small, but significant, changes in movement direction occur as a result of varying train duration or train frequency. 7. The latency to movement onset (i.e., interval from stimulation onset to movement onset) depends upon the frequency of stimulation. A higher frequency of stimulation produces a movement of shorter latency. 8. These data demonstrate that both the site of stimulation and the parameters of stimulation contribute to determining the properties of a movement evoked from the primate SC. In doing so, they contradict the results of early microstimulation studies that suggest that the properties of eye movements evoked from the primate SC are determined solely by the site of stimulation. The findings conflict with the traditional view of collicular function that suggests that the collicular motor representation is purely anatomic. Rather, these data support a revised view whereby the locus, duration, and level of collicular activity contribute to determining the properties of a primate saccadic eye movement. According to this view, independent information relating to desired displacement and saccade velocity are extracted from the spatiotemporal profile of collicular activity.

Animals↗
PubMed2004

Rapid evolution and diversification of mammalian alpha-defensins as revealed by comparative analysis of rodent and primate genes.

Mammalian alpha-defensins constitute a family of cysteine-rich, cationic antimicrobial peptides produced by phagocytes and intestinal Paneth cells, playing an important role in innate host defense. Following comprehensive computational searches, here we report the discovery of complete repertoires of the alpha-defensin gene family in the human, chimpanzee, rat, and mouse with new genes identified in each species. The human genome was found to encode a cluster of 10 distinct alpha-defensin genes and pseudogenes expanding 132 kb continuously on chromosome 8p23. Such alpha-defensin loci are also conserved in the syntenic chromosomal regions of chimpanzee, rat, and mouse. Phylogenetic analyses showed formation of two distinct clusters with primate alpha-defensins forming one cluster and rodent enteric alpha-defensins forming the other cluster. Species-specific clustering of genes is evident in nonprimate species but not in the primates. Phylogenetically distinct subsets of alpha-defensins also exist in each species, with most subsets containing multiple members. In addition, natural selection appears to have acted to diversify the functionally active mature defensin region but not signal or prosegment sequences. We concluded that mammalian alpha-defensin genes may have evolved from two separate ancestors originated from beta-defensins. The current repertoires of the alpha-defensin gene family in each species are primarily a result of repeated gene duplication and positive diversifying selection after divergence of mammalian species from each other, except for the primate genes, which were evolved prior to the separation of the primate species. We argue that the presence of multiple, divergent subsets of alpha-defensins in each species may help animals to better cope with different microbial challenges in the ecological niches which they inhabit.

Amino Acid Sequence↗
PubMedDate not supplied

Allocare in a nocturnal primate: data on the spectral tarsier, Tarsius spectrum.

Non-maternal infant care in many of the small-bodied New World primate species has been hypothesized by some researchers to be related to the high infant/adult weight ratio found in these species. The spectral tarsier, Tarsius spectrum, an Old World primate, has one of the highest infant/adult weight ratios of any primate, with infants weighing between 20-33% of adult weight at birth. On the basis of the hypothesized relationship between allocare and the infant/adult weight ratio, it is predicted that the spectral tarsier will also exhibit extensive allocaretaking behaviour. The results of this study indicate that although spectral tarsiers show care by male and female subadults as well as adult males, it is extremely limited compared to the extensive allocaretaking behavior observed in New World primate species such as Aotus and Callicebus. Spectral tarsier subadult females provide substantially more allocare to infants than do subadult males or adult males. Female subadults were observed sharing food, transporting, grooming, playing, alarm calling, baby-sitting and maintaining physical contact with infants more than other age/sex classes. Although the amount of allocare exhibited by adult males and subadult males was much less than that exhibited by female subadults, the data suggest that adult and subadult male spectral tarsiers do play a small part in the care and socialization of the infant. Adult males and subadult males were both observed occasionally engaging in allocaretaking behaviors such as grooming and playing, as well as frequently patrolling and defending the territory's boundaries. The results from this study suggest that although a high infant/adult weight ratio may be a prerequisite for selection to favor extensive allocare, it is not a causal factor. Additional research is needed in order to understand better the selective pressures involved and the costs and benefits of providing allocare to subadults and adult male spectral tarsiers.

Animals↗
PubMed1998

Evolutionary history of lorisiform primates.

We integrate information from the fossil record, morphology, behavior and molecular studies to provide a current overview of lorisoid evolution. Several Eocene prosimians of the northern continents, including both omomyids and adapoids, have been suggested as possible lorisoid ancestors, but these cannot be substantiated as true strepsirhines. A small-bodied primate, Anchomomys, of the middle Eocene of Europe may be the best candidate among putative adapoids for status as a true strepsirhine. Recent finds of Eocene primates in Africa have revealed new prosimian taxa that are also viable contenders for strepsirhine status. Plesiopithecus teras is a Nycticebussized, nocturnal prosimian from the late Eocene, Fayum, Egypt, that shares cranial specializations with lorisoids, but it also retains primitive features (e.g. four premolars) and has unique specializations of the anterior teeth excluding it from direct lorisiform ancestry. Another unnamed Fayum primate resembles modern cheirogaleids in dental structure and body size. Two genera from Oman, Omanodon and Shizarodon, also reveal a mix of similarities to both cheirogaleids and anchomomyin adapoids. Resolving the phylogenetic position of these Africa primates of the early Tertiary will surely require more and better fossils. By the early to middle Miocene, lorisoids were well established in East Africa, and the debate about whether these represent lorisines or galagines is reviewed. Neontological data are used to address the controversial branching sequences among extent lorisid clades. Data from the skin and scent glands, when integrated with other lines of evidence, suggest that Asian and African lorisines share a common lorisine ancestry. The hypothesis of an African clade containing both pottos and galagos to the exclusion of Asian lorisines is less tenable. True galagines are found in the fossil record of Namibia, while true lorisines are known from the Miocene of Asia. The hypothetical branching sequences can be integrated with behavioral and morphological features to develop an adaptive model of lorisoid divergence. By specializing on two different foraging modes early in their radiation, lorisines and galagines subsequently underwent a chain of integrated evolutionary changes eventually having an impact on many components of locomotor behavior, anatomy, physiology, reproduction, life history, and social behavior. Ongoing evolutionary studies of extant galagines are illuminating population phenomena and processes of speciation in an ecological context.

Africa↗
PubMed2004

The link between exposure to dioxin and endometriosis: a critical reappraisal of primate data.

Endometriosis is a common and enigmatic disease affecting women of reproductive age. In 1993, Dr. Sherry Rier and her colleagues reported a serendipitous finding that quickly sent a shock wave through the endometriosis research community. They found that rhesus monkeys exposed daily for 4 years to dioxin developed endometriosis, with incidence and severity related to dose. The study prompted more animal and epidemiologic studies regarding the link between dioxin exposure and endometriosis. Yet, 10 years after the first piece of evidence was reported, the primate data are still equivocal, and the human data supporting the dioxin-endometriosis association are scanty and conflicting. While many reviewers of the subject recognize the need for more data, other reviewers tend to discount negative studies when reviewing positive studies. In this paper, a critical reappraisal of all evidence from human and primate data is presented. While there is evidence suggesting that exposure to dioxin may facilitate the short-term survival of endometrial implants in non-human primates, this evidence is not supported by both human and non-human primate studies evaluating the relationship between dioxin exposure and the development of spontaneous endometriosis. Weighing all converging evidence, it seems that there are no solid, credible data available at this moment to support the hypothesis that dioxin exposure may lead to the development of endometriosis.

Animals↗
PubMed1993

Anatomical distinctions between the two basal ganglia afferent territories in the primate motor thalamus.

In primates, the efferents of the two basal ganglia output structures, medial globus pallidus and substantia nigra pars reticularis, are completely segregated and target different thalamic regions. Despite similarities demonstrated earlier in non-primate species in the functional properties and ultrastructural features of the terminals of the two pathways, the present findings suggest significant differences between thalamic circuits associated with the two systems in primates. The data presented in this report further support the concept on functional and anatomical diversity of the subdivisions of the primate motor thalamus proposed in 1990 by Hinsky.

Afferent Pathways↗
PubMed1980

Interhemispheric striate projections in the prosimian primate, Galago senegalensis.

Previous studies have shown interhemispheric visual connections in primates to be limited to extrastriate cortex. Using the retrograde transport technique of horseradish peroxidase, we show that in the prosimian primate Galago senegalensis both striate and extrastriate cortex contribute a substantial projection to the contralateral hemisphere. Thus, the lack of an interhemispheric projection from area 17 is not a characteristic of primates and may be peculiar to only a few primate species.

Animals↗
PubMed1978

Contribution of vagal pathways to the renal responses to head-out immersion in the nonhuman primate.

Studies were carried out to determine the contribution of cardiopulmonary receptors to the renal responses to head-out water immersion in the nonhuman primate. Immersion to the suprasternal notch was associated with significant increases in central venous pressure, urine flow, and sodium excretion. The increased sodium excretion was due primarily to a significant increase in the percent of the filtered sodium excreted. Deoxycorticosterone acetate (DOCA) and antiduretic hormone (ADH) had no substantial effects on these responses. The finding of a vasopressin-resistant hyposthenuria is consistent with the natriuresis of immersion being due, at least in part, to a decrease in sodium reabsorption proximal to the diluting segment, possibly the proximal tubule. Bilateral cervical vagotomy had no substantial influence on the renal responses to immersion, demonstrating that cardiopulmonary receptors whose axons traverse the vagus nerves are not necessary for the homeostatic adjustments to central hypervolemia in the primate. Since the renal and cardiovascular responses of the primate to immersion are essentially the same as those seen in man, it is probable that vagal pathways also are not necessary in man. However, it is possible that sympathetic afferents are involved in the natriuresis observed in the primate during immersion.

Animals↗
PubMed2003

Varicosities of intraretinal ganglion cell axons in human and nonhuman primates.

PURPOSE: To describe varicosities of intraretinal ganglion cell axons in the nerve fiber layer of human and nonhuman primate retinas. METHODS: Intraretinal ganglion cell axons of seven human donors (1-85 years old) and two nonhuman primates (Macaca mulatta, 15 and 17 years old) were immunohistochemically stained with an antibody of neurofilament on flatmounted retinas and examined with light microscopy. In addition, the axons within the retinal nerve fiber layer were examined with transmission electron microscopy in one human and one nonhuman retina. The variations of diameters of single axons were measured on transverse- and parallel-cut sections, and the frequency distributions of the diameters were statistically evaluated. RESULTS: Varicosities of the intraretinal ganglion cell axons were found throughout the retinas in both nonhuman primate and human eyes of all ages examined. The varicosities were rich in mitochondria and had desmosome- and hemidesmosome-like junctions with other axons and retinal glial cells. Measured on parallel-cut axons, the mean diameter (+/-SD) of varicosities was 2.7 +/- 0.9 micro m, whereas the mean diameter of intervaricosity regions was 0.7 +/- 0.3 micro m. The diameter distribution for transverse-cut axons was also bimodal, but the two peaks were much closer because the peak of the larger-diameter group decreased. CONCLUSIONS: The results demonstrated that intraretinal ganglion cell axons are predominantly varicose fibers in both human and nonhuman primates. Size variations exist within a single axon's diameter and thereby affect the patterns of diameter distribution seen in transverse-cut preparations. The mitochondria-rich varicosities and the presence of intercellular junctions suggest that the varicosities may be functional sites that serve local high-energy demands of unmyelinated fibers and signal transmission.

Adolescent↗
PubMed2005

Iris-derived cells from adult rodents and primates adopt photoreceptor-specific phenotypes.

PURPOSE: The purpose of this study was to investigate the effects of various genes related to photoreceptor development on rodent and primate iris cells and the potential of iris cells as donor cells for retinal transplantation. METHODS: Adult rat and monkey iris tissue were cultured in serum-free medium containing basic fibroblast growth factor. Gene deliveries of Crx, Nrl, NeuroD and some combinations (Crx-Nrl, Crx-NeuroD) were performed with recombinant retrovirus. Immunocytochemistry, Western blot analysis, RT-PCR, and intracellular recording were used to examine the expression of photoreceptor-specific phenotypes in the iris-derived cells after gene transfer, . Coculture of the iris-derived cells with embryonic retinal explant was conducted, to investigate the potential integration of these cells in coculture conditions. RESULTS: Misexpression of Crx induced adult rat iris cells to express several photoreceptor-specific antigens and transcripts, such as rhodopsin, recoverin, cGMP-gated channel, arrestin, interphotoreceptor retinal-binding protein, rhodopsin kinase, and NeuroD. In primates, a combination of Crx and NeuroD was needed to induce monkey iris-derived cells to adopt photoreceptor-specific phenotypes. Furthermore, the photoreceptor-like cells derived from both rat- and primate-iris tissues showed rod photoreceptor-specific electrophysiological response to light stimuli after Crx and Crx-NeuroD gene transfer, respectively. The results further showed that iris-derived cells integrated in the developing host retina in coculture conditions. CONCLUSIONS: Adult iris-derived cultured cells of both rodents and primates expressed photoreceptor-specific phenotypes by inductions of transcription factors. These iris-derived photoreceptor-like cells have electrophysiological characteristics of rod photoreceptors. Furthermore, they can integrate in the developing retina under coculture conditions.

Animals↗
PubMed2000

Mitochondrial uncoupling protein 2 (UCP2) in the nonhuman primate brain and pituitary.

Energy dissipating mechanisms and their regulatory components represent key elements of metabolism and may offer novel targets in the treatment of metabolic disorders, such as obesity and diabetes. Recent studies have shown that a mitochondrial uncoupling protein (UCP2), which uncouples mitochondrial oxidation from phosphorylation, is expressed in the rodent brain by neurons that are known to regulate autonomic, metabolic, and endocrine processes. To help establish the relevance of these rodent data to primate physiology, we now examined UCP2 messenger RNA and peptide expressions in the brain and pituitary gland of nonhuman primates. In situ hybridization histochemistry showed that UCP2 messenger RNA is expressed in the paraventricular, supraoptic, suprachiasmatic, and arcuate nuclei of the primate hypothalamus and also in the anterior lobe of the pituitary gland. Immunocytochemistry revealed abundant UCP2 expression in cell bodies and axonal processes in the aforementioned nuclei as well as in other hypothalamic and brain stem regions and all parts of the pituitary gland. In the hypothalamus, UCP2 was coexpressed with neuropeptide Y, CRH, oxytocin, and vasopressin. In the pituitary, vasopressin and oxytocin-producing axonal processes in the posterior lobe and POMC cells in the intermediate and anterior lobes expressed UCP2. On the other hand, none of the GH-producing cells of the anterior pituitary was found to produce UCP2. The abundance and distribution pattern of UCP2 in the primate brain and pituitary suggest that this protein is evolutionary conserved and may relate to central autonomic, endocrine and metabolic regulation.

Animals↗
PubMed2002

Histopathological study of intrahepatic islets transplanted in the nonhuman primate model using edmonton protocol immunosuppression.

While islet cell transplantation is a promising way to restore insulin independence to patients with type I diabetes mellitus, a detailed histological analysis of the transplanted, intraportal islets has not yet been reported. Rhesus macaques underwent total pancreatectomy, then had allogeneic isolated islets infused into their portal vein, followed by daclizumab, tacrolimus, and sirolimus to prevent islet rejection. Islets were evenly distributed among the liver lobes. Liver sections from a primate given allogeneic islets 5 d earlier did not display any islet capillary formation, whereas intrahepatic islets transplanted 30 and 90 d before euthanasia showed an abundant capillary supply. Localized hepatocellular glycogenosis was observed surrounding the islets in a primate with functioning islets 7 months post transplant. Liver sections from a primate that rejected islets transplanted 2 months prior displayed only islet remnants with prominent local lymphohistiocytic inflammation and an occasional capillary. We conclude that islets develop an abundant vascular supply within 30 d following transplant and because capillaries persist even following rejection, that the vascular cells are likely from the recipient. While transplanted islets were not vascularized early post transplant, the primates remained insulin independent. The long-term consequence of islets in the liver, marked by the glycogenosis, remains unknown and warrants further study.

Animals↗
PubMed1998

Androgen receptor gene expression in the primate ovary: cellular localization, regulation, and functional correlations.

Excess androgens are associated with a characteristic polyfollicular ovarian morphology; however, it is not known to what extent this problem is due to direct androgen action on follicular development vs. interference with gonadotropin release at the level of the pituitary or hypothalamus. To elucidate potential androgen effects on the ovary, we investigated the cellular localization of androgen receptor (AR) messenger ribonucleic acid (mRNA) in rhesus monkey using in situ hybridization. To investigate the regulation of ovarian AR gene expression, we compared the relative abundance of AR transcripts in monkeys during follicular and luteal phases of the menstrual cycle and in monkeys treated with testosterone. To assess potential functional consequences of AR expression in the primate ovary, we compared AR mRNA levels with indexes of follicular cell proliferation and apoptosis in serial sections from individual follicles. AR mRNA expression was most abundant in granulosa cells of healthy preantral and antral follicles in the primate ovary. Theca interna and stromal cells also expressed AR mRNA, but to a lesser degree than granulosa cells. No significant cycle stage effects were noted in AR mRNA levels; however, larger numbers of animals would be necessary to definitively establish a cycle stage effect. AR mRNA level was significantly increased in granulosa cells and was decreased in theca interna and stromal cells of testosterone-treated monkeys. Importantly, granulosa cell AR mRNA abundance was positively correlated with expression of the proliferation-specific antigen Ki-67 (r = 0.91; P < 0.001) and negatively correlated with granulosa cell apoptosis (r = -0.64; P < 0.001). In summary, these data show that primate ovary AR gene expression is most abundant in granulosa cells of healthy growing follicles, where its expression is up-regulated by testosterone. The positive correlation between granulosa AR gene expression and cell proliferation and negative correlation with programmed cell death suggests that androgens stimulate early primate follicle development.

Animals↗
PubMed1995

Posttranscriptional regulation of primate Ldhc mRNA by its AUUUA-like elements.

The Ldhc locus encodes the testis-specific isozyme of lactate dehydrogenase in mammals. In our efforts to understand the regulatory mechanisms involved in expression of Ldhc, we recognized the possibility that this gene could be post-transcriptionally regulated in certain species as the 3'-untranslated region (3'-UTR) of Ldhc in primates, but not rodents, contains a number of AU-rich motifs and is conserved. To determine whether the primate Ldhc mRNA is posttranscriptionally regulated, comparison of baboon and mouse Ldhc mRNA stability was made in a cell-free system. The results indicated that the baboon mRNA is labile, while that of mouse, which does not contain the AU-rich motifs, is highly stable. Consistent with these results, the steady state level of primate Ldhc was found to be 8 to 12 fold lower than that of the mouse. We show that in a transformed murine germ cell line, the human Ldhc mRNA is moderately unstable, and removal of its 3'-UTR leads to stabilization of the mRNA. Mutations disrupting the AU-rich motifs of human Ldhc result in stabilization of the mRNA in vitro. On the basis of these observations, we conclude that stability of the primate Ldhc transcript is regulated by dispersed AU-rich elements found in its 3'-UTR. Because AU-rich motifs similar to these are found in many mRNAs, these findings may have broad implications.

Animals↗
PubMed2003

Insights into the evolution of human bipedalism from experimental studies of humans and other primates.

An understanding of the evolution of human bipedalism can provide valuable insights into the biomechanical and physiological characteristics of locomotion in modern humans. The walking gaits of humans, other bipeds and most quadrupedal mammals can best be described by using an inverted-pendulum model, in which there is minimal change in flexion of the limb joints during stance phase. As a result, it seems logical that the evolution of bipedalism in humans involved a simple transition from a relatively stiff-legged quadrupedalism in a terrestrial ancestor to relatively stiff-legged bipedalism in early humans. However, experimental studies of locomotion in humans and nonhuman primates have shown that the evolution of bipedalism involved a much more complex series of transitions, originating with a relatively compliant form of quadrupedalism. These studies show that relatively compliant walking gaits allow primates to achieve fast walking speeds using long strides, low stride frequencies, relatively low peak vertical forces, and relatively high impact shock attenuation ratios. A relatively compliant, ape-like bipedal walking style is consistent with the anatomy of early hominids and may have been an effective gait for a small biped with relatively small and less stabilized joints, which had not yet completely forsaken arboreal locomotion. Laboratory-based studies of primates also suggest that human bipedalism arose not from a terrestrial ancestor but rather from a climbing, arboreal forerunner. Experimental data, in conjunction with anatomical data on early human ancestors, show clearly that a relatively stiff modern human gait and associated physiological and anatomical adaptations are not primitive retentions from a primate ancestor, but are instead recently acquired characters of our genus.

Adaptation, Biological↗
PubMed1995

Individual differences in macaques' responses to stressors based on social and physiological factors: implications for primate welfare and research outcomes.

Primates are used extensively in a variety of research settings. Federal regulations in the US mandate that caretakers provide for the 'psychological well-being of laboratory primates'. One of the difficulties in implementing this law has been both in the definition of psychological well-being and in the need to deal with each primate species and, in some cases, age or sex class, uniquely. Non-human primates exhibit distinct individual differences in their behavioural and physiological responses to experimental challenges and caretaking procedures. We have been investigating what factors can predict some of these individual differences, and have found that factors both intrinsic and extrinsic are significant. Extrinsic factors found to predict individual differences in response to stressors include the nature and prior experience with the challenge, the presence of familiar peers and availability of social support. Intrinsic factors include cognitive interpretations of the challenge and temperamental differences in reactivity. These studies highlight the importance of understanding the context and individual psychology of macaques in order to provide laboratory environments conducive to their welfare, and in order to understand the impact experimental and caretaking procedures are likely to have on the health and welfare of our subjects.

Aggression↗