3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Exploring patterns of morphological integration in the crania of papio hamadryas ursinus and homo sapiens(2017) Hemingway, JasonMorphological integration is the pattern of correlation or covariation among parts due to genetic, developmental and functional processes, and is essential for the viability of an organism. Integration among processes is not uniform but forms distinct modules allowing for their independent evolvability and is thus central to the study of biological evolution. The incongruence between phylogenies estimated using the genotype and the cranial morphology in both the Papionini primates as well as the Hominidae possibly result from the disregard of character integration. Regarding the degree of morphological integration humans display extremely low levels of integration among the primates, while the baboon possesses extremely high levels. This thesis set out to address three broad aims regarding integration of the baboon and human cranium; namely 1) to study the effect of allometry on measures of integration, and when allometry and sexual dimorphism had been accounted for, 2) to assess the patterning of morphological integration into morphological modules; and finally, 3) to assess differences in the pattern of covariation between the cranial base, cranial vault and facial skeleton in humans and baboons. Although allometric growth is divided into neural and somatic, the findings suggest that the effect of allometry conceals more detailed patterns of morphological integration likely resulting from genetic and developmental processes, and should therefore be accounted for in studies of morphological integration. It is unlikely that allometry among cranial regions constrains evolutionary diversity, but rather offers a path of least resistance. The second aim offered up novel methods of exploring the pattern of morphological covariation using clustering and network methods that supported current hypotheses and proposed that the oral and basicranial regions are comprised of additional modules; however, rigorous scientific scrutiny is required for its support. iv The third aim involved the analysis of integration between the cranial base, cranial vault, and facial skeleton. The results supported the proposal that humans and nonhuman primates share a similar pattern of integration likely reflecting shared developmental processes among the primates, but with key differences probably relating to functional demands. Integration between these three cranial regions primarily involve their relative positioning and proportions. The broad pattern of integration likely reflects the role of the cranium as the supporting framework around the organs and functional capsules, the “real” modules, which accommodate one another epigenetically as they develop. The recognition of both independent modules and their pervasive integration are important and depend primarily on the nature of the investigation.Item The skull and mandible of the South African baboon.(1975) Trevor-Jones, Trevor RubidgeThe skull and mandible of the baboon. This is a morphological study of the skulls and mandibles of 102 specimens from known localities in Southern Africa. A detailed reference book on the anatomy of the baboon is particularly important because of the increasing use of this animal in medical science. The skulls and mandibles of captive animals are referred to but are not included in the comparative study since animals in captivity are subject to dietetic disturbances and other factors not yet fully understood. The cranium of an adult male skull is described in all normae. Comparisons are made with the crania of seven adult male baboons from widely separated known localities. This study shows that two main craniofacial types, with intermediate types, occur among the crania of South African baboons. Type 1. crania have small maxillary ridges, shallow maxillary fossae, ventrally directed zygomatic bones, large ventral orbital apertures, well developed superciliary ridges, high temporal lines and sagittal crests. Type 11. crania have large flared maxillary ridges, deep maxillary fossae, ventrolateral ly directed zygomatic bones, small ventral orbital apertures, large supraorbital tori, low temporal lines and no sagittal crests. This apparent1y supports the specific and subspecific claims of some observers. However, a critical examination of the crania of six adult female baboons from the same troop at Bindura, Rhodesia, shows that similar craniofacial types occur among female baboons. It is possible to associate mandibular types with the craniofacial types in adult male baboons. This is not the case with female baboon mandibles.Item Signal transduction pathways controlling the induction of bone formation by macroporous biomimetic matrices(2015-03-27) Klar, Roland ManfredIn spite of vigorous research efforts to date the induction of bone formation by macroporous coral-derived constructs when implanted heterotopically in the rectus abdominis muscle of the non-human primate Chacma baboon Papio ursinus has not yet been resolved and needs to be assigned. More importantly, the apparent redundancy of molecular signals singly initiating the induction of bone formation in primate species and the heterotopic induction of endochondral bone formation by the mammalian recombinant human transforming growth factor –β3 (rhTGF-β3) isoform have not yet been assigned and need to be mechanistically resolved. Using the rectus abdominis muscle of Papio ursinus the study sought to molecularly determine how coral-derived macroporous constructs and doses of the hTGF-β3 isoform initiate the induction of bone formation. To elucidate the function of osteoclastogenesis and Ca2+, biomimetic coral-derived 7% hydroxyapatite/calcium carbonate (7% HA/CC) devices were supplemented either with 240 μg zoledronate bisphosphonate, an osteoclast binding antagonist, or 500 μg of the calcium channel blocker verapamil hydrochloride. Additionally but in separate coralderived bioreactors, 125 μg rhTGF-β3 and/or 125 μg hNoggin were added to answer the question of how TGF-β3 induces bone formation. All devices were then subsequently implanted within heterotopic sites of the rectus abdominis muscle of 6 Papio ursinus and left in vivo for 15, 60 and 90 days. Harvested specimens were subjected to histomorphometrical and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis. Collagen Type IV expression supported by extensive vascularisation was detected and observed respectively in all implants after 15 days in vivo. Importantly the zoledronate treated specimens possessed delayed tissue patterning and morphogenesis,Item Occult hepatits B virus (HBV) infection in the Chacma Baboon (Papio ursinus orientalis)(2011-11-23) Dickens, CarolineMembers of the family Hepadnaviridae have been detected in both avian and mammalian species. They have a very limited host range, and among the nonhuman primates, have been found to occur naturally in chimpanzees, gorillas, gibbons, orang-utans and woolly monkeys. The human hepatitis B virus (HBV) has been shown to infect chimpanzees, Barbary macaques and tree shrews. During the course of a previous study, to determine the susceptibility of baboons (Papio ursinus orientalis) to HBV infection, HBV DNA was detected in the serum of 2 baboons prior to their inoculation with HBV-positive human serum, raising the possibility that baboons are naturally infected with a hepadnavirus. Therefore the aim of this study was to determine the prevalence of HBV in wildcaught baboons and to molecularly and functionally characterise the virus isolated from these baboons. DNA was extracted from the sera of wild-caught baboons and four separate regions of the HBV genome amplified by nested polymerase chain reaction (PCR). Samples were only considered to be positive for HBV if at least three of these regions amplified. DNA was extracted from the liver tissue of one of the HBV DNA-positive baboons using a proteinase K digestion followed by a phenolchloroform extraction and ethanol precipitation. From this extract, the complete HBV genome was amplified by nested PCR of eight overlapping subgenomic fragments, and sequenced. This sequence was analysed phylogenetically using both the PHYLIP and Simmonic software packages. A selective real time PCR using SYBR®-green detection was used to detect covalently closed circular (ccc) DNA. RNA was extracted from the baboon liver tissue using a guanidinium-acidphenol extraction method, reverse transcribed and portions of the HBV genome amplified by nested PCR. Transmissibility of the virus was tested by injecting four experimentally naïve baboons individually with serum from four HBV DNApositive baboons and followed for 26 weeks. HBV was detected in the serum of 5/69 (7,2%) wild-caught baboons by Southern hybridization and in 11/49 (22,4%) adult and 4/20 (20,0%) juvenile wild caught baboons. This gave an overall prevalence of 21,7% in the baboon population surveyed. Serologically, the baboon sera were negative for all markers of HBV infection and alanine aminotransferse (ALT) levels were normal. In the one baboon liver tissue available, HBcAg was detected by immunohistochemical staining in some of the hepatocyte nuclei, but HBsAg was not detected. Phylogenetic analysis of the complete genome of the HBV isolate found it to cluster with subgenotype A2, a surprising result considering that subgenotype A1 predominates in South Africa. However, unlike other subgenotype A2 isolates, the basic core promoter had the G1809T / C1812T double mutation characteristic of subgenotypes A1 and A3 and the precore region had the G1888A mutation unique to subgenotype A1. These mutations in the basic core promoter and precore regions have previously been shown to reduce the expression of the precore and core proteins. Four additional mutations in the polymerase, surface, X and core open reading frames (ORFs) further differentiated the baboon HBV strain form the majority of previously sequenced subgenotype A2 isolates. cccDNA was detected at low levels in the baboon liver tissue. Regions of the precore/core and surface ORFs were amplified off reverse transcribed cDNA. These results demonstrate HBV replication in the baboon liver. Transmission of the virus was shown by the detection of HBV DNA in the sera of the four inoculated baboons at various times throughout the 26 week follow-up period. These baboons also showed transient seroconversion for HBsAg and HBeAg during this period with intermittent fluctuations in ALT levels. Moreover, using DNA extracted from liver tissue obtained at necropsy from one of the injected baboons, the sequence of the HBV surface gene amplified was found to be identical to the sequence of the isolate from inoculum. The finding of subgenotype A2 in the baboon is paradoxical because subgenotypes A1 and A3 as well as genotypes D and E predominate in Africa. The possibility exists that subgenotype A2 is an older strain that has been overtaken by these other strains. There is however a scarcity of subgenotype A2 sequencing data from Africa and a higher circulation of this subgenotype could be uncovered with more extensive molecular epidemiological studies in more remote areas. Alternatively, a recent discovery of alternative compartmentalization of subgenotype A2 infections in the peripheral blood lymphocyte population of individuals from India, where subgenotype A1 also predominates, could explain the lack of detection of this subgenotype in Africa. Occult hepatitis B infection is defined as the presence of HBV DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for HBsAg by currently available assays. The detection of HBV DNA in the baboon liver and serum in the absence of serological markers therefore classifies this infection as occult. To our knowledge, this is the first study to demonstrate a naturally occurring occult HBV infection in non-human primates.