Klüver-Bucy syndrome in Pick's disease.
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Affective Symptoms↗
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Stabilization and mobility of the head and trunk in wild monkeys during terrestrial and flat-surface walks and gallops.
This study investigated the patterns of rotational mobility (> or =20 degrees ) and stability (< or =20 degrees ) of the head and trunk in wild Indian monkeys during natural locomotion on the ground and on the flat-topped surfaces of walls. Adult hanuman langurs (Semnopithecus entellus) and bonnet macaques (Macaca radiata) of either gender were cine filmed in lateral view. Whole-body horizontal linear displacement, head and trunk pitch displacement relative to space (earth horizontal), and vertical head displacement were measured from the cine films. Head-to-trunk pitch angle was calculated from the head-to-space and trunk-to-space measurements. Locomotor velocities, cycle durations, angular segmental velocities, mean segmental positions and mean peak frequencies of vertical and angular head displacements were then calculated from the displacement data. Yaw rotations were observed qualitatively. During quadrupedal walks by both species, the head was free to rotate in the pitch and yaw planes on a stabilized trunk. By contrast, during quadrupedal gallops by both species, the trunk pitched on a stabilized head. During both gaits in both species, head and trunk pitch rotations were symmetrical about comparable mean positions in both gaits, with mean head position aligning the horizontal semicircular canals near earth horizontal. Head pitch direction countered head vertical displacement direction to varying degrees during walks and only intermittently during gallops, providing evidence that correctional head pitch rotations are not essential for gaze stabilization. Head-to-space pitch velocities were below 350 deg. s(-1), the threshold above which, at least among humans, the vestibulo-ocular reflex (VOR) becomes saturated. Mean peak frequencies of vertical translations and pitch rotations of the head ranged from 1 Hz to 2 Hz, a lower frequency range than that in which inertia is predicted to be the major stabilizer of the head in these species. Some variables, which were common to both walks and gallops in both species, are likely to reflect constraints in sensorimotor control. Other variables, which differed between the two gaits in both species, are likely to reflect kinematic differences, whereas variables that differed between the two species are attributed primarily to morphological and behavioural differences. It is concluded that either the head or the trunk can provide the nervous system with a reference frame for spatial orientation and that the segment providing that reference can change, depending upon the kinematic characteristics of the chosen gait.
Animals↗
Photosensitive and photostable pigments in the retinae of Old World monkeys.
Microspectrophotometric measurements of retinal receptors are reported for eight species of Old World monkey. Although the animals vary greatly in size, colourings and habitat, they all appear to be trichromats and the peak sensitivities of their cones invariably lie near 430, 535 and 565 nm. This consistent pattern contrasts with the results reported earlier for New World monkeys and with the results reported here for Tupaia glis. The trichromacy of frugivorous catarrhine monkeys may have co-evolved with a particular class of coloured fruit. Short-wave cones were rare in all species. The ratio of the numbers of middle-wave and long-wave cones varied between individual animals, but had an overall value close to unity. In the case of all the species examined here, we have recorded a photostable pigment in the inner segments of rods and cones. The latter pigment has a peak sensitivity close to 420 nm and an absorbance spectrum that is narrower than that of a photosensitive visual pigment.
Animals↗
Catarrhine photopigments are optimized for detecting targets against a foliage background.
The colour vision of many primates is trichromatic, whereas that of all other mammals is thought to be dichromatic or monochromatic. Moreover, the triplets of cone pigments in different catarrhines (Old World apes and monkeys) are strikingly similar in their spectral positions. We ask whether the selective advantage of trichromacy lies in an enhanced ability to find edible leaves or fruit. Further, we ask whether any factor in these two search tasks has constrained the particular set of cone spectral sensitivities observed in all catarrhines. We measured the spectral properties of the natural environments of six primate species in Uganda: Pan troglodytes, Cercopithecus mitis, Cercopithecus ascanius, Lophocebus albigena, Colobus guereza and Colobus badius. We concentrated on the fruit and leaves in their diets and the leaves of the trees that make up the background against which these diet items must be found. We plotted these measured stimuli in colour spaces appropriate for each primate species, and found that both frugivory and folivory are facilitated by the extra dimension of colour vision found in catarrhines but lacking in most other mammals. Furthermore, by treating the task of searching for food as a signal-detection task, we show that, of all possible combinations of cone sensitivities, the spectral positions of the actual primate pigments are optimal for finding fruit or young leaves against the background of mature leaves. This is because the variance of the chromaticities of the mature leaves is minimised in one channel of the primate's colour vision, so allowing anything that is not a mature leaf to stand out.
Algorithms↗
Prenatal susceptibility to carcinogenesis by xenobiotic substances including vinyl chloride.
The carcinogenicity of vinyl chloride for experimental animals when administered transplacentally is reviewed in comparison with known transplacental carcinogens, including those that, like vinyl chloride, are dependent on enzyme-mediated metabolic conversion to a reactive intermediate in maternal or fetal tissues. Vinyl chloride is converted by mixed-function oxidases to the reactive metabolite chlorooxirane, the carcinogenicity of which is also reviewed. Vinyl chloride is unequivocally a transplacental carcinogen for the rat. No evidence exists, however, to support the hypothesis that exposure of male rats to vinyl chloride or any other carcinogen confers an increased risk of tumor development on their progeny. Many structural analogs of vinyl chloride, i.e., substituted ethylenes, are also carcinogenic for adult animals, and can with confidence likewise be predicted to be effective transplacental carcinogens.
Animals↗
Human evolution.
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Allergy and Immunology↗
Representation of cone signals in the primate retina.
Vision begins with specialized retinal circuits that encode diverse types of information. For Old World primates, these circuits sample three submosaics formed by cone photoreceptors sensitive to short, middle, and long wavelengths. For spatial acuity, the photon catch between any two cones is compared for discrimination of patterns as fine as the cone mosaic. For color vision, the photon catch between different cone types is compared for discrimination of fine spectral differences on the basis of hue. The retinal circuits for these two tasks differ at the synaptic level to form distinct representations of signals from the cone mosaic.
Animals↗
Two-dimensional spatial structure of receptive fields in monkey striate cortex.
Measurements of the spatial contrast sensitivity function and orientation selectivity of visual neurons in the foveal striate cortex (V1) of primates were interpreted within the context of a model of the two-dimensional spatial structure of their receptive fields. Estimates of the spatial dimensions of the receptive fields along the axis of preferred orientation were derived from the application of the model and were compared with estimates of the smallest spatial subunit in the dimension orthogonal to the preferred orientation. Some measure of agreement was found with corresponding estimates of parameters for psychophysical channels in human foveal vision.
Animals↗
Loss of olfactory receptor genes coincides with the acquisition of full trichromatic vision in primates.
Olfactory receptor (OR) genes constitute the molecular basis for the sense of smell and are encoded by the largest gene family in mammalian genomes. Previous studies suggested that the proportion of pseudogenes in the OR gene family is significantly larger in humans than in other apes and significantly larger in apes than in the mouse. To investigate the process of degeneration of the olfactory repertoire in primates, we estimated the proportion of OR pseudogenes in 19 primate species by surveying randomly chosen subsets of 100 OR genes from each species. We find that apes, Old World monkeys and one New World monkey, the howler monkey, have a significantly higher proportion of OR pseudogenes than do other New World monkeys or the lemur (a prosimian). Strikingly, the howler monkey is also the only New World monkey to possess full trichromatic vision, along with Old World monkeys and apes. Our findings suggest that the deterioration of the olfactory repertoire occurred concomitant with the acquisition of full trichromatic color vision in primates.
Alouatta↗
Pervasive adaptive evolution in primate seminal proteins.
Seminal fluid proteins show striking effects on reproduction, involving manipulation of female behavior and physiology, mechanisms of sperm competition, and pathogen defense. Strong adaptive pressures are expected for such manifestations of sexual selection and host defense, but the extent of positive selection in seminal fluid proteins from divergent taxa is unknown. We identified adaptive evolution in primate seminal proteins using genomic resources in a tissue-specific study. We found extensive signatures of positive selection when comparing 161 human seminal fluid proteins and 2,858 prostate-expressed genes to those in chimpanzee. Seven of eight outstanding genes yielded statistically significant evidence of positive selection when analyzed in divergent primates. Functional clues were gained through divergent analysis, including several cases of species-specific loss of function in copulatory plug genes, and statistically significant spatial clustering of positively selected sites near the active site of kallikrein 2. This study reveals previously unidentified positive selection in seven primate seminal proteins, and when considered with findings in Drosophila, indicates that extensive positive selection is found in seminal fluid across divergent taxonomic groups.
Animals↗
Heterogeneous genomic molecular clocks in primates.
Using data from primates, we show that molecular clocks in sites that have been part of a CpG dinucleotide in recent past (CpG sites) and non-CpG sites are of markedly different nature, reflecting differences in their molecular origins. Notably, single nucleotide substitutions at non-CpG sites show clear generation-time dependency, indicating that most of these substitutions occur by errors during DNA replication. On the other hand, substitutions at CpG sites occur relatively constantly over time, as expected from their primary origin due to methylation. Therefore, molecular clocks are heterogeneous even within a genome. Furthermore, we propose that varying frequencies of CpG dinucleotides in different genomic regions may have contributed significantly to conflicting earlier results on rate constancy of mammalian molecular clock. Our conclusion that different regions of genomes follow different molecular clocks should be considered when inferring divergence times using molecular data and in phylogenetic analysis.
Animals↗
Serological and structural comparison of immunodeficiency viruses from man, African green monkey, rhesus monkey and sooty mangabey.
We have studied the serological relationship among the human immunodeficiency virus type 1 (HIV-1), and three simian immunodeficiency viruses (SIV). SIVagm was isolated from African green monkeys (Cercopithecus aethiops), and compared with the previously described isolates of SIVmac from a rhesus macaque (Macaca mulatta) and SIVsm from a sooty mangabey (Cercocebus atys). With respect to the glycoproteins, the simian viruses represent a subgroup apparently different from HIV. To classify HIV and SIV isolates further, we compared tryptic peptide maps of the core polypeptides p 18 and p 24 of HIV-2, three HIV-1 and five SIV isolates. Each peptide map was distinguishable, and differences are most prominent between the HIV-1 group and the SIVmac/SIVsm group. HIV-2 is very similar to SIVmac and SIVsm. The three SIVagm isolates form a more heterogeneous group. The p24s of all SIVagms are more similar to the p24s of HIV-1, but with respect to p 18, one isolate is similar to HIV-1, while the two others are more related to SIVmac, SIVsm, and HIV-2.
Cercopithecidae↗
Serum prolactin concentrations in mangabey (Cercocebus atys lunulatus) and patas (Erythrocebus patas) monkeys in response to stress, ketamine, TRH, sulpiride and levodopa.
An homologous radioimmunoassay for human serum prolactin was validated to measure serum prolactin in 10 mangabey and 7 patas monkeys. Mean basal levels of serum prolactin were almost identical in the males of both species and in immature and mature males. However, basal levels were higher in females than in males. Serum prolactin was enhanced by stress, i.v. injection of TRH and intramuscular injection of a potent dopamine antagonist (sulpiride). The rise in serum prolactin observed after i.m. injection of ketamine hydrochloride used as anaesthetic was of small amplitude and short duration. Oral administration of levodopa was followed by a significant fall in serum prolactin. Sexual maturity did not influence the responses to TRH or sulpiride. The mangabeys were more sensitive to sulpiride but less sensitive to levodopa than were the patas monkeys. The variations in serum prolactin levels observed in these monkeys under the influence of stress, TRH, sulpiride and levodopa are similar to those observed in man to the same stimuli, although the experimental conditions were quite different.
Animals↗
Changes in concentrations of serum prolactin, FSH, oestradiol and progesterone and of the sex skin during the menstrual cycle in the mangabey monkey (Cercocebus atys lunulatus).
Daily blood samples were collected from 6 regularly menstruating mangabey monkeys. Because serum LH could not be measured by a radioimmunoassay for human LH, Day 0 was taken as the day of maximum serum oestradiol concentration. The hormone patterns were very similar to those of other cercopithecids and women. However, the peak of serum progesterone was lower in mangabeys than in women. There was no distinct peak of serum oestradiol during the luteal phase of mangabeys but the average levels were higher than during the early follicular phase, a pattern more similar to that in other non-human primates than in women. Serum prolactin rose by about 50%, 48 h after the serum oestradiol peak, then declined during the mid-luteal phase before rising at the end of the cycle. Changes in the sex skin dimensions followed the same pattern as the serum oestradiol concentrations.
Animals↗
Reproductive exocrine and endocrine profile of female langur monkeys, Presbytis entellus.
In 5 caged langurs menstrual cycle length (for 125 cycles) varied from 18 to 45 days with a mean +/- s.d. of 26.3 +/- 3.6 days. Menstruation lasted for 2 days. A distinct cycle of vaginal smear cells was observed with a maximum cornification on Day 10 coinciding with the serum oestradiol peak. A monophasic pattern of vaginal temperature with a significant nadir on Day 11, 1 day after the oestradiol peak, was observed. Serum sialic acid concentrations directly reflected the oestrogenic activity and showed a significant peak on Day 10, coinciding with the oestradiol peak and was followed by a progesterone rise. Langurs menstruated throughout the year without showing any sign of summer amenorrhoea. We suggest that maximum cornification, vaginal temperature nadir and serum sialic acid peak could be used as markers for prediction and detection of the time of ovulation in langur monkeys.
Animals↗
The use of non-human primates as animal models for the study of hepatitis viruses.
Hepatitis viruses belong to different families and have in common a striking hepatotropism and restrictions for propagation in cell culture. The transmissibility of hepatitis is in great part limited to non-human primates. Enterically transmitted hepatitis viruses (hepatitis A virus and hepatitis E virus) can induce hepatitis in a number of Old World and New World monkey species, while the host range of non-human primates susceptible to hepatitis viruses transmitted by the parenteral route (hepatitis B virus, hepatitis C virus and hepatitis delta virus) is restricted to few species of Old World monkeys, especially the chimpanzee. Experimental studies on non-human primates have provided an invaluable source of information regarding the biology and pathogenesis of these viruses, and represent a still indispensable tool for vaccine and drug testing.
Animals↗
Structure of rhesus monkey relaxin predicted by analysis of the single-copy rhesus monkey relaxin gene.
The gene encoding rhesus monkey relaxin has been investigated. A cDNA library was prepared using corpus luteal RNA from a pregnant rhesus monkey, cDNA clones encoding relaxin were isolated and the nucleotide sequence was determined. The amino acid sequence of rhesus monkey preprorelaxin, predicted from the cDNA, demonstrates that the sequence has not been strongly conserved when compared with that of man, although features characteristic of the relaxin molecule have been maintained. This structural information will allow production of rhesus monkey relaxin, leading to studies investigating the bioactivity of relaxin in a homologous primate system. Southern blot analysis indicated that there is only one relaxin gene in the rhesus monkey and baboon genomes. In this respect these primate genomes are different from the human genome which contains two relaxin genes.
Amino Acid Sequence↗
Independent origin of the growth hormone gene family in New World monkeys and Old World monkeys/hominoids.
The growth hormone (GH) gene family represents an erratic and complex evolutionary pattern, involving many evolutionary events, such as multiple gene duplications, positive selection, the birth-and-death process and gene conversions. In the present study, we cloned and sequenced GH-like genes from three species of New World monkeys (NWM). Phylogenetic analysis strongly suggest monophyly for NWM GH-like genes with respect to those of Old World monkeys (OWM) and hominoids, indicating that independent gene duplications have occurred in NWM GH-like genes. There are three main clusters of genes in putatively functional NWM GH-like genes, according to our gene tree. Comparison of the ratios of nonsynonymous and synonymous substitutions revealed that these three clusters of genes evolved under different kinds of selective pressures. Detailed analysis of the evolution of pseudogenes showed that the evolutionary pattern of this gene family in platyrrhines is in agreement with the so-called birth-and-death process.
Animals↗