OBSERVATIONS ON THE DEVELOPMENT OF A POTTO BORN IN CAPTIVITY.
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Functional anatomy of the trunk musculature in the slow loris (Nycticebus coucang).
Lorisid locomotor and postural behaviour exhibits a number of features that distinguish it clearly from other primates. The comparative myological study of the trunk in the slow loris (Nycticebus coucang) and the squirrel monkey (Saimiri sp.) presented here reveals differences that are related to unique aspects of lorisid positional behaviour. While quadrupedal running and leaping requires flexion and extension of the spine, slow climbing quadrupedalism in lorisids depends on spinal lateral flexion and rotation. The contrasting development of the epaxial musculature in the two species dissected reflects these different requirements. Bipedal suspension is a common posture in the lorisids during which rotation and dorsiflexion of the head is made possible by the robustly developed deep, dorsal, cervical musculature. The long lower lever arm in the M. rectus abdominis may play a significant role in the ventroflexion required to regain a quadrupedal stance.
Abdominal Muscles↗
Chromosome painting between human and lorisiform prosimians: evidence for the HSA 7/16 synteny in the primate ancestral karyotype.
Multidirectional chromosome painting with probes derived from flow-sorted chromosomes of humans (Homo sapiens, HSA, 2n = 46) and galagos (Galago moholi, GMO, 2n = 38) allowed us to map evolutionarily conserved chromosomal segments among humans, galagos, and slow lorises (Nycticebus coucang, NCO, 2n = 50). In total, the 22 human autosomal painting probes detected 40 homologous chromosomal segments in the slow loris genome. The genome of the slow loris contains 16 sytenic associations of human homologues. The ancient syntenic associations of human chromosomes such as HSA 3/21, 7/16, 12/22 (twice), and 14/15, reported in most mammalian species, were also present in the slow loris genome. Six associations (HSA 1a/19a, 2a/12a, 6a/14b, 7a/12c, 9/15b, and 10a/19b) were shared by the slow loris and galago. Five associations (HSA 1b/6b, 4a/5a, 11b/15a, 12b/19b, and 15b/16b) were unique to the slow loris. In contrast, 30 homologous chromosome segments were identified in the slow loris genome when using galago chromosome painting probes. The data showed that the karyotypic differences between these two species were mainly due to Robertsonian translocations. Reverse painting, using galago painting probes onto human chromosomes, confirmed most of the chromosome homologies between humans and galagos established previously, and documented the HSA 7/16 association in galagos, which was not reported previously. The presence of the HSA 7/16 association in the slow loris and galago suggests that the 7/16 association is an ancestral synteny for primates. Based on our results and the published homology maps between humans and other primate species, we propose an ancestral karyotype (2n = 60) for lorisiform primates.
Animals↗
Cholinesterases in the tongue of the potto (Perodicticus potto).
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Cytochemistry of the oocyte of Loris tardigradus lydekkerianus (Cabr.) and Macaca mulatta mulatta (Zimmerman).
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Sperm-sperm associations in the loris epididymis.
In a few mammals, the passage of maturing spermatozoa through the epididymis is characterized by development of persistent associations between one or more neighboring cells over the acrosomal region. The converse situation is described here in the loris, Nycticebus coucang, a prosimian primate. Loris spermatozoa released at spermiation enter the caput epididymidis as single cells and then become stacked in rouleaux of 2-8 spermatozoa there, the peri-acrosomal plasmalemma of one being linked by a unique junctional complex to that of its neighbor. However, by the time the cauda is reached, all the spermatozoa have separated again to lie as single cells, which now display major aggregations of ordered material over the concave surface of the acrosome. The functional significance of these unusual sperm surface-related phenomena in the loris epididymis is not clear.
Animals↗
A comparison of the femoral head and neck trabecular architecture of Galago and Perodicticus using micro-computed tomography (microCT).
Innovations in micro-computed tomography (microCT) in the medical field have resulted in the development of techniques that allow the precise quantification of bone density and fabric related parameters of trabecular bone. For the purpose of this study, the technique was applied to a small sample of Perodicticus potto and Galago senegalensis femora to see if differences in loading environment elicit the predicted effects on trabecular structure. While the overall bone volume was approximately three times larger in the potto, there was no significant difference in the apparent volume density in the two taxa. When regional differences in the proximal femur were examined, the cancellous bone of the femoral head of Perodicticus potto and Galago senegalensis, while not differing in volume density, showed differences in trabecular orientation, with the potto having more randomly oriented trabeculae than the bushbaby. This was as hypothesized, given that the bushbaby submits its femora to more stereotypical loading environments than the potto. In the femoral neck, the cancellous bone was not only more randomly oriented, it was also denser in the potto compared with the bushbaby. This suggests that trabecular morphology may be extremely sensitive to certain differences in the loading environment and that this information, combined with information on cortical bone structure and external geometry, will result in a more complete understanding of how bone shape and composition correspond to loading and locomotor patterns. Ultimately, a synthesis of these different lines of evidence may have considerable applications in paleontological studies that attempt to reconstruct bone use from morphology.
Animals↗
The chromosomes of Nycticebus coucang (Boddaert, 1785) (Primates: Prosimii).
The high-quality karyotype of a specimen of Nycticebus coucang is described and illustrated. The X chromosome is found to be indistinguishable from that of the greater galagos, and may represent a synapomorphic trait. The y chromosome is a medium to small submetacentric (3.2% TCL) and constitutes one of the larger Y chromosomes known in primates. N. coucang is found to have multiple NOR-bearing chromosomes in contrast to the single pair found in galagine and catarrhine monkeys. Since a single NOR-bearing pair is often considered ancestral for primates, this new finding may have important implications for the evolution of these cistrons. One of the chromosomal polymorphisms in this specimen is a pericentric inversion, involving a NOR-bearing autosomal pair (no. 6), that alters the position of the active site. Further, homologues 2p differ by a paracentric inversion. These results confirm that lorisiforms are characterized by considerable chromosomal polymorphism.
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Neuronal and synaptic arrangements of the lateral geniculate nucleus in night-active primates.
The lateral geniculate nucleus (LGN) of Aotus trivirgatus and Nycticebus coucang shows two types of neurons at the ultrastructural level: a large thalamo-cortical relay neuron (TCR) and a small neuron of Golgi type II, which is considered to be an interneuron. The interneuron contains small aggregations of synaptic vesicles in the perikaryon adjacent to the cell membrane in synaptic contact to a TCR neuron. Only in the perikaryon of the interneurons can cilia have their origin. After unilateral enucleation, neurofilamentous or dark degenerations of large boutons with round vesicles (type RL) occur in the outer layers of the contralateral LGN and in the inner layers of the ipsilateral LGN. The optic terminals establish synaptic contacts in the glomerulus with dendritic spines of the TCR neurons and with presynaptic dendrites (F2) of interneurons.
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Multiple L1 progenitors in prosimian primates: phylogenetic evidence from ORF1 sequences.
One of the uncertainties regarding the evolution of L1 elements is whether there are numerous progenitor genes. We present phylogenetic evidence from ORF1 sequences of slow loris (Nycticebus coucang) and galago (Galago crassicaudatus) that there were at least two distinct progenitors, active at the same time, in the ancestor of this family of prosimian primates. A maximum parsimony analysis that included representative L1s from human, rabbit, and rodents, along with the prosimian sequences, revealed that one of the galago L1s (Gc11) grouped very strongly with the slow loris sequences. The remaining galago elements formed their own unique and strongly supported clade. An analysis of replacement and silent site changes for each link of the most parsimonious tree indicated that during the descent of the Gc11 sequence approximately two times more synonymous than nonsynonymous substitutions had occurred, implying that the Gc11 founder was functional for some time after the split of galago and slow loris. Strong purifying selection was also evident on the galago branch of the tree. These data indicate that there were two distinct and contemporaneous L1 progenitors in the lorisoid ancestor, evolving under purifying selection, that were retained as functional L1s in the galago lineage (and presumably also in the slow loris). The prosimian ORF1 sequences could be further subdivided into subfamilies. ORF1 sequences from both the galago and slow loris have a premature termination codon near the 3' end, not shared by the other mammalian sequences, that shortens the open reading frame by 288 bp. An analysis of synonymous and nonsynonymous substitutions for the 5' and 3' portions, that included intra- and inter-subfamily comparisons, as well as comparisons among the other mammalian sequences, suggested that this premature stop codon is a prosimian acquisition that has rendered the 3' portion of ORF1 in these primates noncoding.
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A cross-species comparison of neutral lipid composition of milk fat of prosimian primates.
The fatty acid composition of milk fat is known to be affected by dietary and genetic differences, while the milk triacylglycerol structure is believed to be attuned to the needs of the subsequent lipolysis during gastrointestinal passage. The availability of milk samples from eight species of prosimian primates, whose milk triacylglycerol structure had not been analyzed, offered an opportunity to further assess these ideas. The milk samples were collected by manual expression and the lipids extracted with chloroform/methanol (2:1, vol/vol). The lipid classes were resolved by thin-layer chromatography, and the neutral lipids subjected to detailed analyses by capillary gas-liquid chromatography of fatty acids and molecular species of triacylglycerols using nonpolar and polarizable liquid phases. The milk samples were found to differ greatly in total fat content (4-73%) and in the composition of the neutral lipid classes and molecular species. The concentration of triacylglycerols ranged from 88-95%, free fatty acids from 0.5-10%, alkyldiacylglycerols from 0.5-5.0%, and diacylglycerols, monoacylglycerols and free and esterified cholesterol made up the remainder. The fatty acid chain length ranged from C8-C24, with palmitic (16-31%) and oleic (13-40%) acids being the major components in most of the species. In all instances, the molecular association of the fatty acids differed from random distribution by a higher proportion of the monoacid (trioleoyl) and diacid (dipalmitoyloleoyl) glycerols. The phylogenetic influences on neutral milk lipid composition, however, remained unclear, as some of the differences between closely related species were greater than those between more distantly related ones.
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Home range and ranging pattern in the slender loris(Loris tardigradus lydekkerianus).
The home range and ranging pattern of the slender loris (Loris tardigradus lydekkerianus) was studied for 21 months in a scrub jungle in Dindigul, Tamil Nadu, south India. Sixteen individuals were observed for a total of 2261 hours. Home ranges were measured for eight adult individuals and eight juvenile and subadult individuals. Males had significantly larger home ranges than the females, and home range size increased post-weaning. The ranging patterns involved minimal female intrasexual overlap, large male intrasexual overlap and large intersexual range overlap.
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"Venom" of the slow loris: sequence similarity of prosimian skin gland protein and Fel d 1 cat allergen.
Bites inflicted on humans by the slow loris (Nycticebus coucang), a prosimian from Indonesia, are painful and elicit anaphylaxis. Toxins from N. coucang are thought to originate in the brachial organ, a naked, gland-laden area of skin situated on the flexor surface of the arm that is licked during grooming. We isolated a major component of the brachial organ secretions from N. coucang, an approximately 18 kDa protein composed of two 70-90 amino-acid chains linked by one or more disulfide bonds. The N-termini of these peptide chains exhibit nearly 70% sequence similarity (37% identity, chain 1; 54% identity, chain 2) with the two chains of Fel d 1, the major allergen from the domestic cat (Felis catus). The extensive sequence similarity between the brachial organ component of N. coucang and the cat allergen suggests that they exhibit immunogenic cross-reactivity. This work clarifies the chemical nature of the brachial organ exudate and suggests a possible mode of action underlying the noxious effects of slow loris bites.
Amino Acid Sequence↗
Odor familiarity and female preferences for males in a threatened primate, the pygmy loris Nycticebus pygmaeus: applications for genetic management of small populations.
Here we use sexual selection theory to develop a logistically simple, yet effective, method for the manipulation of female reproductive behavior for conservation goals. Mate choice leading to nonrandom mating patterns can exacerbate the loss of genetic diversity in small populations. On theoretical grounds, females should choose high-quality mates. A prediction stemming from chemical communication theory is that competitive males will be better able to saturate an area with scent marks. If this is true, females should mate preferentially with males whose odors they encounter most frequently. We tested this hypothesis with the pygmy loris, Nycticebus pygmaeus, a threatened and poorly studied nocturnal prosimian. For several weeks females were exposed repeatedly to the urine from a particular male, and were then allowed to choose between a male whose odors were familiar and one whose odors were novel. Females showed an unusually strong preference for the familiar-odor male, as indicated by several behavioral measures of mate preference. Conservation managers can use this method as a tool to obtain reproductive pairings that will maximize genetic compatibility and diversity. For example, unsuccessful males may be given the opportunity to reproduce. In captive populations, studbook managers often select pairs in order to optimize outbreeding, but these selected pairings may not coincide with the preferences of the individual animals involved. Although several authors have made theoretical arguments for manipulating mate choice for conservation, this is a novel test of a proximate mechanism that can be manipulated, cultivating applications rather than mere implications.
Animal Communication↗
The medial terminal nucleus of the monkey: evidence for a 'complete' accessory optic system.
The retinal projection to the medial terminal nucleus of the accessory optic system of the monkey was examined in several primate species which had received intraocular injections of [3H]proline or [3H]fucose. These data show that the medial terminal nuclei of the slow loris, marmoset monkey, and squirrel monkey all receive a sparse input from the contralateral retina.
Animals↗
Comparative studies on cortical representation of vision.
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Laminar organization of acetylcholinesterase and cytochrome oxidase in the lateral geniculate nucleus of prosimians.
Hess and Rockland [Hess and Rockland (1983) Brain Res. 289, 322-325] proposed that the distribution of acetylcholinesterase within the lateral geniculate nucleus might correlate with the daily activity patterns shown by primates. In diurnal primates, the magnocellular laminae show a greater acetylcholinesterase reaction product. In nocturnal primates, the parvocellular laminae are more heavily stained. We have examined the laminar distribution of acetylcholinesterase and cytochrome oxidase in the lateral geniculate nucleus of a series of rare prosimian primates. In all prosimians examined, the most dense acetylcholinesterase reaction product is seen in the parvocellular layers of the lateral geniculate nucleus. Heavy cytochrome oxidase activity is seen in both the magnocellular and parvocellular layers, but not the koniocellular layers of the prosimian lateral geniculate nucleus. We have also employed a polyclonal antibody to choline acetyltransferase to examine the laminar organization or cholinergic activity in the Galago (Bushbaby) lateral geniculate nucleus. We report that choline acetyltransferase immunoreactivity does not correlate with acetylcholinesterase activity in the prosimian lateral geniculate nucleus. Although the lateral geniculate nucleus is more immunoreactive than most other thalamic structures and although the intercalated koniocellular laminae demonstrate somewhat lighter choline acetyltransferase immunoreactivity, no great difference in staining intensity is seen between the parvocellular and magnocellular laminae. In addition, we examined the phenotype of known inputs to assess the laminar specificity of cholinergic projections to the bushbaby lateral geniculate nucleus. Layer VI of primary visual cortex, which is known to be a source of acetylcholinesterase in the parvocellular layers, does not contain cholinergic cells, nor does the pretectal nucleus, which projects mainly to the parvocellular layers. The parabigeminal nucleus is cholinergic; however, this nucleus is known to project to the koniocellular layers, along with the non-cholinergic superior colliculus. Finally, the pedunculopontine tegmental nucleus, which provides a strong input to many regions of the thalamus, including the lateral geniculate nucleus, is cholinergic. The laminar organization of its input to the lateral geniculate nucleus is not known. Increased acetylcholinesterase reaction product within the parvocellular layers of the lateral geniculate nucleus is common to all strepsirhine primates. The pattern is also seen in the only two nocturnal haplorhine primates, Tarsius and Aotus (owl monkey). The relation of this increased acetylcholinesterase activity to cholinergic function remains unclear.(ABSTRACT TRUNCATED AT 400 WORDS)
Acetylcholinesterase↗
Locomotor mechanics of the slender loris (Loris tardigradus).
The quadrupedal walking gaits of most primates can be distinguished from those of most other mammals by the presence of diagonal-sequence (DS) footfall patterns and higher peak vertical forces on the hindlimbs compared to the forelimbs. The walking gait of the woolly opossum (Caluromys philander), a highly arboreal marsupial, is also characterized by diagonal-sequence footfalls and relatively low peak forelimb forces. Among primates, three species--Callithrix, Nycticebus, and Loris--have been reported to frequently use lateral-sequence (LS) gaits and experience relatively higher peak vertical forces on the forelimbs. These patterns among primates and other mammals suggest a strong association between footfall patterns and force distribution on the limbs. However, current data for lorises are limited and the frequency of DS vs. LS walking gaits in Loris is still ambiguous. To test the hypothesis that patterns of footfalls and force distribution on the limbs are functionally linked, kinematic and kinetic data were collected simultaneously for three adult slender lorises (Loris tardigradus) walking on a 1.25 cm horizontal pole. All subjects in this study consistently used diagonal-sequence walking gaits and always had higher peak vertical forces on their forelimbs relative to their hindlimbs. These results call into question the hypothesis that a functional link exists between the presence of diagonal-sequence walking gaits and relatively higher peak vertical forces on the hindlimbs. In addition, this study tested models that explain patterns of force distribution based on limb protraction angle or limb compliance. None of the Loris subjects examined showed kinematic patterns that would support current models proposing that weight distribution can be adjusted by actively shifting weight posteriorly or by changing limb stiffness. These data reveal the complexity of adaptations to arboreal locomotion in primates and indicate that diagonal-sequence walking gaits and relatively low forelimb forces could have evolved independently.
Adaptation, Physiological↗