Due to overpopulation of African elephants in South Africa and the consequent threat to biodiversity, the need for a method of population control has become evident. The potential use of the porcine zona pellucida (pZP) vaccine as a safe and effective means for population control is explored. While potential effects of pZP treatment on social behaviour of African elephants have been investigated, no examination of the influence of pZP vaccination on the endocrine correlates in treated females has been undertaken. The ovarian activity of freeranging, pZP-treated African elephant females was monitored non-invasively for one year duration by measuring faecal progestagen concentrations via enzyme immunoassay. Behavioural observations were recorded for comparison with progestagen concentrations and to determine any behavioural changes surrounding the pZP vaccine darting event. Each elephant under study showed progestagen concentrations rising above baseline at some period during the study indicating luteal functionality. Average progestagen concentrations were 1.61 ± 0.46 ìg/g. Within sampled females, 42.9% exhibited oestrous cycles within the range reported for African elephants, 14.3% had irregular cycles, and 42.9% did not appear to be cycling. Average oestrous cycle duration was 14.72 ± 0.85 weeks. Behavioural oestrous coincided with the onset of the luteal phase and a subsequent rise in progestagen concentrations. Focal sampling to determine activity budgets before and after the darting event revealed no significant change in behavioural activities. In the week following immunization, individual progestagen concentrations decreased significantly from overall average concentrations. Average progestagen concentrations positively correlated with rainfall and with herd dominance. No association between average individual progestagen concentrations or cyclicity status with age, lactation, or parity were detected. Earlier determination of efficacy was made indicating reproductive control was established 22 months post-treatment. Results indicate the presence of ovarian activity amongst pZP-treated female African elephants in two years following initial immunization. Further study should be aimed toward studying the long term effects of pZP vaccination on the reproductive function of female African elephants. / Dissertation (MSc)--University of Pretoria, 2010. / Production Animal Studies / unrestricted

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第19371号 / 人健博第31号 / 新制||人健||3(附属図書館) / 32385 / 新制||人健||3 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 坪山 直生, 教授 市橋 則明, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

No description available.

<p> A stress analysis of porcine aortic valve leaflets in diastole at 80 mm. Hg. in-vitro is presented. Incorporations of local surface geometry, leaflet material inhomogeneity, anisotropy and non-linearity are applied. The stress theory used is a modified form of the thin membrane stress theory for a homogeneous, linearly elastic and orthotropic lamina. Modifications are made so that the linear Hooke's Law equations of stress may be applied to the inhomogeneous, non-linearly elastic and orthotropic thin membrane aortic valve leaflets. </p> <p> Stress calculations are made on the premise that the diastolic valve leaflets at 80 mm. Hg. are in pre-transition (that is, characterized by a small elastic modulus) for the circumferential direction, and in post-transition (that is, characterized by a large elastic modulus) for the radial direction. Circumferential stresses are calculated to be relatively negligible; they are estimated to be less than 1 gm/mm². Radial stresses for the non coronary leaflet lie primarily in the 0 to 20 gm/mm² range. The regions of the largest stress concentrations are in the areas of mutual leaflet coaptation, especially near the Nodes of Aranti. A progressive increase of the radial stresses from the sinus annulus edges toward the coaptation edges of the leaflets is also observed. Based on the one valve reported , it appears that the left coronary leaflet is the highest stressed and the right coronary leaflet is the least stressed. Central leaflet radial stresses for the right coronary leaflet are in the 0 to 10 gm/mm² range, as compared to 0 to 20 gm/mm² for the non coronary and left coronary leaflets. </p> <p> The question as to whether the diastolic strains of the valve leaflets are in pre-transition, transition or post-transition is raised. The resolution of the question is seen to be critical to the validity of the stress analysis. It is also realized that further improvements in the analysis are possible through improvements and refinements to the experimental methods used in obtaining the necessary inputs for the analysis. </p> / Thesis / Master of Engineering (ME)

The effect of culture media and mycotoxin on porcine preimplantation embryonic development has been investigated. In the first experiment, porcine embryonic cleavage rates were similar in NCSU-23 and PZM-3 culture media, while more blastocysts were produced in PZM-3 (P<0.05). BAX and BCL2L1 transcription levels were similar in blastocysts cultured in both media. Cleavage rates were significantly decreased in the presence of cycloheximide (P<0.05), and both á-amanitin and cycloheximide completely inhibited blastocyst formation. In the mycotoxin experiment, porcine embryonic cleavage rates decreased in 10 ìM á-ZEA group, while blastocyst rates decreased in 30 ìM á-ZEA group (P<0.05). Total cell numbers of blastocysts were significantly lower in the 10 µM á-ZEA group (P<0.05). The transcription levels of POU5F1 and BCL2L1 were similar, while that of BAX and the ratio of BAX/BCL2L1 significantly increased in 3 ìM and 10 ìM á-ZEA groups compared to control group.

The active site of porcine kidney microsomal aminopeptidase was investigated using single, multiple and EDTA inactivation kinetic studies. Good inhibitors invariably contained a zinc-coordinating group such as the mercapto moiety, which proved to be the best ligand for aminopeptidase. Due to the potency of β -mercaptoethylamine, derivatives of this compound were examined for aminopeptidase inhibition. (S)-2-amino-4-methyl-l-pentanethiol (L-leucinthiol) exhibited the largest potency and specificity towards aminopeptidase when compared against carboxypeptidase A and thermolysin, two similar zinc-peptidases. The presence of a zinc-coordination subsite, two hydrophobic pocket subsites and a second amine-binding subsite (distinct from that responsible for substrate recognition) were discerned and the binding modes of amino acid hydroxamates and mercaptoamines compared using Yonetani-Theorell inhibition kinetics. Aminopeptidase does not show virtually any stereoselectivity between L-and D-leucine hydroxamate while greater than a 1,000-fold preference is seen for L-leucinthiol over the D isomer. Also, the amino group of mercaptoamines is crucial to the binding of these inhibitors whereas that of the hydroxamate compounds does not seen to contribute much to their binding. The differences in binding between hydroxamates and mercaptoamines are postulated to be a consequence of the product analogue nature of the former and transition state analogue character of the latter. L-leucine hydroxamate is proposed to bind in a backwards orientation while the D isomer binds in the normal substrate-like position. Similarly, L-leucinthiol is proposed to bind in the same fashion as substrate. Design of future inhibitors should endeavour to: (1) lower the pᵏₐ of the α-amino group, (2) include an extended chain structure capable of binding to additional hydrophobic pockets, (3) incorporate a second amine moiety into the structure to interact with the second amine-binding subsite and (4) replace the mercapto group with a more potent zinc ligand such as the selenol group. / Thesis / Master of Science (MSc)

Influenza A virus (IAV) is a significant problem worldwide, and respiratory disease is further complicated by secondary bacterial infection. The emergence of highly pathogenic strains of IAV in conjunction with the increase of antibiotic-resistant bacteria threatens human health. A large-animal model effective for study of polymicrobial infection comparable to humans must therefore be developed. IAV has been studied extensively in small animals, including mice, rats and ferrets. However, these species frequently require IAV adaptation, reducing the capacity of these models to adequately represent human infection. Furthermore, species commonly used lack likeness to humans in both the presentation of symptoms and in lethality of infection. However, pigs are naturally susceptible to unadapted IAV and are considered to be the 'mixing vessel' for the recent pandemic IAV virus. Pigs are also susceptible to infection with Staphylococcus aureus, the most commonly isolated bacteria from IAV-infected human adults. Therefore, the use of pigs in the study of polymicrobial respiratory infections would be ideal for characterizing a host immune response comparable to humans, as well as for the development of diagnostics and therapeutics. Using this novel model, we determined that pigs are susceptible to Staphylococcus aureus, swine IAV, and polymicrobial infection. Furthermore, we showed that IAV infection predisposes pigs to Staphylococcus aureus pneumonia, and this susceptibility is dependent on day post-IAV infection. / Master of Science

High concentrations of intracellular glutathione enhance the in vitro production of porcine embryos. Six experiments were conducted to study the effects of varying concentrations of different supplements to the in vitro maturation (IVM) medium on in vitro fertilization (IVF) and in vitro culture (IVC), and evaluate subsequent embryo viability. In Exp. 1, 2, 3, and 4, porcine oocytes were matured in either 3.3 mM cysteine, 150 μM cysteamine, 3.3 mM cysteine and 150 μM cystemaine; 1.0 mM glycine, 2.5 mM glycine, 5.0 mM glycine; 1.0 mM L-glutamate, 2.5 mM L-glutamate, 5.0 mM L-glutamate; and 3.3 mM L-α-aminobutyrate, 25 μM β-mercaptoethanol, 3.3 mM cysteine and 25 μM β-mercaptoethanol, or 3.3 mM L-α-aminobutyrate and 25 μM β-mercaptoethanol. After IVM (44 h), concentrations of intracellular glutathione (GSH) were determined using a colorimetric assay based on absorbency. The supplements that elicited significantly (P < 0.05) the greatest increase in GSH concentrations were 3.3 mM cysteine, 1.0 mM L-glutamate, 3.3 mM L-α-aminobutyrate, and 3.3 mM L-α-aminobutyrate with 25 25 μM β-mercaptoethanol. In Exp. 5, oocytes matured with 3.3 mM L-α-aminobutyrate and 25 μM β-mercaptoethanol had a significantly less (P < 0.05) occurrence of polyspermy and greater occurrence of MPN formation during IVF compared to the other treatment groups and a significantly greater percentage (P < 0.05) of embryos reaching the 2 cell developmental stage by 48 h post-IVF and blastocyst stage of development by 144 h post-IVF compared to the other treatment groups. In Exp. 6, treatment had no effect on the time of cell death. The times at which embryo mortality was significantly the greatest (P < 0.05) were located within the middle of IVC. The approximate time of the onset of cell death occurred between 24 to 42 h post-IVF with the greatest occurrence around 36 h. These results suggest that supplementing 3.3 mM L-α-aminobutyrate and 25 μM β-mercaptoethanol into the IVM medium 1) increases intracellular GSH concentrations by the end of IVM, 2) decreases the occurrence of polyspermy during IVF, 3) increases the MPN formation during IVF, and 3) increases embryo development parameters during IVC. Supplementation to the maturation media does not have an effect on cell death during embryo development. The onset of cell death appears to occur between 24 to 42 h post-IVF with the greatest occurrence around 36 h post-IVF. In order to increase the success of in vitro derived porcine embryos and offspring, the basic fundamentals of the system need to be fully understood. / Master of Science

Le présent travail a pour objectif de mesurer les effets du sevrage précoce des porcelets sur la taille de portée suivante d'une truie dans le but de tenir compte de cet effet environnemental dans les évaluations génétiques à l'aide d'un modèle animal-BLUP. Les effets de la longueur de lactation et de l'intervalle sevrage-saillie fécondante (ISSF) sur la taille de portée subséquente d'une truie ont d'abord été estimés en utilisant un modèle animal à partir de données provenant de deux troupeaux de sélection de Génétiporc pratiquant simultanément deux types de sevrage : le MMEW (lactation de moins de 14 jours, habituellement pas d'accouplement avant le deuxième œstrus) ou le sevrage conventionnel (truies sevrées après au moins 14 jours de lactation, habituellement accouplement au premier œstrus). Ces effets ont été estimés séparément pour les races Landrace et Yorkshire. Des effets linéaire, quadratique et logarithmique de la longueur de lactation sur la taille de portée suivante ont été examinés. L'effet de l'ISSF sur la taille de portée suivante a été étudié en utilisant une méthode basée sur des variables à seuil et une approche utilisant des polynômes segmentés. Dans le but de valider si les effets du type de sevrage pouvaient être généralisés à un ensemble de troupeaux ayant des techniques d'élevage différentes, les mêmes types d'analyses ont été faits, cette fois-ci en considérant des portées provenant d'une centaine de troupeaux québécois du programme PEG (Programme d'Évaluation Génétique). L'analyse des données de deux troupeaux de Génétiporc a montré des effets importants de la longueur de la lactation et de l'ISSF sur la taille de portée suivante. Ces effets, allant jusqu'à 0,8 porcelet/portée pour la longueur de la lactation et jusqu'à 1 porcelet/portée pour l'ISSF, étaient beaucoup plus prononcés chez les Landrace que chez les Yorkshire. Les effets estimés pour la longueur de la lactation et l'ISSF sur la taille de portée suivante étaient similaires à ceux obtenus dans l'analyse des données de plus de 100 troupeaux québécois. La longueur de la lactation et l'ISSF devraient donc être considérés dans les modèles d'évaluation génétique des tailles de portée des porcs afin d'augmenter la précision des valeurs génétiques prédites par le modèle. La méthode des polynômes segmentés peut être utilisée pour prédire la taille de portée suivante comme une fonction continue de l'ISSF ou pour déduire des facteurs d'ajustement pour corriger la taille de portée pour l'ISSF précédent.

Master of Science / Department of Animal Sciences and Industry / Duane L. Davis / Culturing stem cells is usually done on tissue-culture treated plastic. Over time the cells change their gene expression and start to differentiate. Porcine umbilical cord (PUC) stem cells express the embryonic transcription factors Oct4, Nanog and Sox2 and changes in their expression may be useful for to evaluating culture-induced changes in the cells. We developed an extract of porcine Wharton’s jelly matrix (JMX) that may provide some characteristics of the stem cell niche located in the umbilical cord. Our extract used whole cords and enzyme digestion to simplify preparation of the product. We compare cells cultured on plastic to those grown on thin and thick gels of JMX in four experiments. In Exp 1a and b, growing PUCs on a thick JMX coating for 3(1a) or 4(1b) d increased the number of cells at the end of culture (P < 0.05) with minimal effects on gene expression. In Exp 2 we compared PUCs grown on thin and thick layered JMX with added collagen (+C) and to control cells. The JMX layers caused the cells to adopt a small, round shape and to form clumps or colonies during culture. No differences (P > 0.10) were seen between thin10 +C and control wells for viable and total cell counts but thick layered +C resulted in decreased numbers of viable cells compared to thin + C (P < 0.10) and control wells (P < 0.05). In a follow up experiment (Exp. 3) growing the PUCs mixed within, rather than plating on top of, a thick layer of JMX + C caused marked morphological changes with dense 3-dimensional structures formed. Exp 4 compared JMX allowed to gel for 10 (Thin10 +C) or 60 (Thin60 +C) min before the non-gelled fraction was removed. There were no effects on cell numbers at the end of culture (P > 0.10) but Sox2 expression was increased in Thin60 +C compared to controls on plastic (P < 0.05) and Thin10 +C (P < 0.10). In summary, JMX extracts change cell morphology and in some formats increased cell proliferation and may increase Sox2 expression. Further investigation is needed to fully understand the effects of JMX on PUCs.