Lemur
Cheirogaleidae
Lemuridae
Madagascar
Primates
Sympatry
Lorisidae
Natural and experimental oral infection of nonhuman primates by bovine spongiform encephalopathy agents. (1/103)
Experimental lemurs either were infected orally with the agent of bovine spongiform encephalopathy (BSE) or were maintained as uninfected control animals. Immunohistochemical examination for proteinase-resistant protein (prion protein or PrP) was performed on tissues from two infected but still asymptomatic lemurs, killed 5 months after infection, and from three uninfected control lemurs. Control tissues showed no staining, whereas PrP was detected in the infected animals in tonsil, gastrointestinal tract and associated lymphatic tissues, and spleen. In addition, PrP was detected in ventral and dorsal roots of the cervical spinal cord, and within the spinal cord PrP could be traced in nerve tracts as far as the cerebral cortex. Similar patterns of PrP immunoreactivity were seen in two symptomatic and 18 apparently healthy lemurs in three different French primate centers, all of which had been fed diets supplemented with a beef protein product manufactured by a British company that has since ceased to include beef in its veterinary nutritional products. This study of BSE-infected lemurs early in their incubation period extends previous pathogenesis studies of the distribution of infectivity and PrP in natural and experimental scrapie. The similarity of neuropathology and PrP immunostaining patterns in experimentally infected animals to those observed in both symptomatic and asymptomatic animals in primate centers suggests that BSE contamination of zoo animals may have been more widespread than is generally appreciated. (+info)The oestrous cycle of the brown lemur, Lemur fulvus. (2/103)
Examination of vaginal smears and observations of the colour and tumescence of the genitalia and discharge of mucus of 9 brown lemurs indicated that the oestrous cycle lasted for 30 days and that cycles occurred between September and July. The timing of cycles of females housed in visual isolation differed from that of females able to see other lemurs, indicating that the oestrous cycle in this species can be influenced by different housing conditions. (+info)Transposition of SRY into the ancestral pseudoautosomal region creates a new pseudoautosomal boundary in a progenitor of simian primates. (3/103)
We have isolated the prosimian lemur homologues for STS and SRY. FISH unambiguously co-localized STS with SHOX, IL3RA, ANT3 and PRK into the meiotic X-Y pairing region (PAR) of lemurs. In contrast to the close proximity of SRY to the pseudoautosomal boundary (PAB) on the Y chromosome in simian primates, SRY maps distant from the PAR in lemurs. Most interestingly, we were able to determine a DNA sequence divergence of 12.5% between the human and lemur SRY HMG box. This divergence directs to a 52 million year period of separate evolution of human and lemur SRY genes. Phylogenetically, this time period falls in between the times that prosimians and New World monkeys branched from the human lineage. Thus, we conclude that approximately 52 million years ago a transposition of SRY into the ancestral eutherian PAR distal to STS and PRK defined a new PAB in a simian progenitor. By this event, STS and PRK, amongst other genes, were excluded from the X-Y crossover process and thus became susceptible to rearrangements and/or deterioration on the Y chromosome in simian primates. (+info)Amino acid sequences of the alpha and beta chains of adult hemoglobin of the brown lemur, Lemur fulvus fulvus. (4/103)
Globin prepared from hemoglobin of the brown lemur (Lemur fulvus fulvus) was separated into alpha and beta chains by chromatography on a CM 52 column. The S-aminoethylated alpha and beta chains were each digested with trypsin and resulting peptides were isolated. The amino acid sequences of the tryptic peptides were established. The ordering of these peptides in the alpha and beta chains was deduced from the homology of their amino acid sequences with that of human adult hemoglobin. The primary structure of brown lemur hemoglobin thus obtained differs from that of human hemoglobin in 15 amino acids in the alpha chain and 26 in the beta chain. (+info)Remarkable species diversity in Malagasy mouse lemurs (primates, Microcebus). (5/103)
Phylogenetic analysis of mtDNA sequence data confirms the observation that species diversity in the world's smallest living primate (genus Microcebus) has been greatly underestimated. The description of three species new to science, and the resurrection of two others from synonymy, has been justified on morphological grounds and is supported by evidence of reproductive isolation in sympatry. This taxonomic revision doubles the number of recognized mouse lemur species. The molecular data and phylogenetic analyses presented here verify the revision and add a historical framework for understanding mouse lemur species diversity. Phylogenetic analysis revises established hypotheses of ecogeographic constraint for the maintenance of species boundaries in these endemic Malagasy primates. Mouse lemur clades also show conspicuous patterns of regional endemism, thereby emphasizing the threat of local deforestation to Madagascar's unique biodiversity. (+info)Androgen levels and female social dominance in Lemur catta. (6/103)
Morphological and behavioural traits which improve agonistic power are subject to intrasexual selection and, at the proximate level, are influenced by circulating androgens. Because intrasexual selection in mammals is more intense among males, they typically dominate females. Female social dominance is therefore unexpected and, indeed, rare. Ring-tailed lemurs (Lemur catta) are sexually monomorphic primates in which all adult females dominate all males. The goal of our study was to test the prediction that female dominance in this species is associated with high androgen levels. Using two captive groups, we collected data on agonistic behaviour and non-invasively assessed their androgen concentrations in faeces and saliva by enzyme immunoassay. We found that adult female L. catta do not have higher androgen levels than males. However, during the mating season there was a twofold increase in both the androgen levels and conflict rates among females. This seasonal increase in their androgen levels was probably not due to a general increase in ovarian hormone production because those females showing the strongest signs of follicular development tended to have low androgen concentrations. At the individual level neither the individual aggression rates nor the proportion of same-sexed individuals dominated were correlated with their androgen levels. We conclude that female dominance in ring-tailed lemurs is neither based on physical superiority nor on high androgen levels and that it is equally important to study male subordination and prenatal brain priming effects for a complete understanding of this phenomenon. (+info)The human vomeronasal organ. Part II: prenatal development. (7/103)
During the 20th century, the human vomeronasal organ (VNO) has been controversial regarding its structure, function, and even identity. Despite reports that provide evidence for its presence throughout prenatal and postnatal ontogeny, some studies and numerous textbooks declare its absence in late fetal and postnatal humans. To that end, the present study was designed to establish firmly whether the human VNO is homologous with that of other mammals and whether it degenerates (partially or completely) or persists throughout prenatal development. Fifty human embryos and fetuses (33 d to 32 wk fertilisation age) and 2 neonates were examined by light microscopy. Four embryonic primates (mouse lemurs) were examined for a comparison of VNO embryogenesis. The presence or absence and structural characteristics of the VNO and supporting tissues are described. The first appearance of the VNO was in the form of bilateral epithelial thickenings of the nasal septum, the vomeronasal primordium. The primordia invaginated between 37 and 43 d of age and formed the tubular VNO. The tubular VNO was located dorsally at a variable distance from, but was always spatially separated from the paraseptal cartilages. The mouse lemurs examined in this study and other reports from the literature indicate that the human VNO resembles that of primates having functional VNOs until just after a tubular VNO is formed. Examination of the VNO and adjacent tissues suggested that the VNO may lose receptor cells and corresponding vomeronasal nerves and become a ciliated, pseudostratified epithelium between approximately 12 and 14 wk of age. Our findings indicate the prenatal human VNO goes through 3 successive stages: early morphogenesis, transformation (of the epithelium), and growth. These observations indicated that (1) all embryonic humans develop a vomeronasal organ which is homologous with the VNOs of other mammals, but which has become displaced and highly variable in relative location during embryogenesis; (2) the human vomeronasal organ does not degenerate prenatally, but very likely loses the functional components of the vomeronasal complex of other mammals; and (3) the remnant of the human VNO persists until birth and beyond. (+info)The existence of the vomeronasal organ in postnatal chimpanzees and evidence for its homology with that of humans. (8/103)
It is currently thought that New World monkeys, prosimians, and humans are the only primates to possess vomeronasal organs (VNOs) as adults. Recent studies of the human VNO suggest that previous investigations on Old World primates may have missed the VNO. We examined nasal septa from the chimpanzee (Pan troglodytes) grossly and histologically for comparison with nasal septa from humans, Old World monkeys (Macaca fascicularis, M. nemistrina) and prosimian primates (Microcebus murinus, Otolemur garnettii). Grossly, chimpanzees had depressions on the nasal septum similar to fossae reported anterior to the VNO openings in humans. Histologically, chimpanzees and humans had bilateral epithelial tubes which were above the superior margin of the paraseptal cartilages (vomeronasal cartilage homologue). The epithelial tubes had a homogeneous ciliated epithelium. These structures were thus positionally and structurally identical to the human VNO and unlike the well-developed prosimian VNOs which were surrounded by vomeronasal cartilage. Macaques had no structures which resembled the VNO of either the prosimians or humans. The results demonstrate that the VNO is present postnatally in the chimpanzee and is almost identical to the human VNO in its anatomical position and histological structure. This in turn suggests that the reported absence of the VNO in at least some adult Old World primates is artifactual, and that further study may provide evidence for its existence in other species. (+info)I'm sorry for any confusion, but the term "Lemur" is not typically used in medical definitions. It is a common name that refers to primates belonging to the infraorder Lemuriformes. They are native to Madagascar and are divided into five families: Cheirogaleidae (dwarf lemurs), Daubentoniidae (aye-aye), Indriidae (indris, sifakas, and avahis), Lepilemuridae (sportive lemurs), and Lemuridae (true lemurs). If you have any questions related to medical terminology or health concerns, I would be happy to help!
Cheirogaleidae is a family of small primates also known as dwarf lemurs or mouse lemurs. They are native to Madagascar and are characterized by their rodent-like appearance and nocturnal behavior. This family includes several genera and species, such as Cheirogaleus, Microcebus, Mirza, and Allocebus. These primates are known for their ability to adapt to various environments, from forests to dry regions, and have a varied diet that includes fruits, insects, and small vertebrates. They are also known for their unique hibernation behavior during the dry season, where they lower their metabolic rate and body temperature to conserve energy.
I'm sorry for any confusion, but "Lemuridae" is not a medical term. It is a taxonomic family that includes lemurs, which are primates native to the island of Madagascar. In animal taxonomy, Lemuridae is part of the infraorder Lemuriformes and superfamily Lemuroidea.
If you have any questions related to medical terminology or healthcare topics, please feel free to ask!
I'm sorry for any confusion, but "Madagascar" is not a medical term. It is actually the fourth-largest island country in the world, located in the Indian Ocean, off the southeastern coast of Africa. If you have any questions about medical terms or concepts, I'd be happy to help answer those!
In a medical or scientific context, "Primates" is a biological order that includes various species of mammals, such as humans, apes, monkeys, and prosimians (like lemurs and lorises). This group is characterized by several distinct features, including:
1. A forward-facing eye position, which provides stereoscopic vision and depth perception.
2. Nails instead of claws on most digits, except for the big toe in some species.
3. A rotating shoulder joint that allows for a wide range of motion in the arms.
4. A complex brain with a well-developed cortex, which is associated with higher cognitive functions like problem-solving and learning.
5. Social structures and behaviors, such as living in groups and exhibiting various forms of communication.
Understanding primates is essential for medical and biological research since many human traits, diseases, and behaviors have their origins within this group.
Sympatry is a term used in biology and ecology, including in the study of human health and disease, to describe the situation where two or more species or populations coexist in the same geographical area and often interact with each other. In medical contexts, sympatry may refer to the co-occurrence of two or more diseases or pathogens within a particular population or geographic region.
For example, in epidemiology, sympatric distribution of infectious diseases can occur when multiple pathogens are transmitted by the same vector or host species, leading to overlapping distributions and potential interactions between the diseases. This can have implications for disease surveillance, control, and prevention efforts.
It is important to note that sympatry should not be confused with symbiosis, which refers to a close and often long-term biological interaction between two different biological organisms, typically involving mutual benefits or cooperation.
Lorisidae is not a medical term, but a taxonomic family in the order Primates. It includes various species of slow lorises, which are small, nocturnal primates found primarily in Southeast Asia. They have a round head, large eyes, and a wet nose, which helps them to have an excellent sense of smell. Slow lorises have a toxic bite, produced by mixing their saliva with the secretions from glands located on their elbows.
While not directly related to medical terminology or healthcare, understanding the classification and characteristics of different animal species can be important in fields such as zoonotic disease research, public health, and wildlife conservation.